Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 01/22/07

.SYNOPSIS...A COASTAL EDDY AND MARINE LAYER WILL KEEP LOW CLOUDS OVER THE AREA THROUGH THE NIGHT. STRONG OFFSHORE FLOW DEVELOPS ON SUNDAY WITH CLEAR SKIES THROUGH MONDAY ALONG WITH SOME GUSTY NORTH TO NORTHEAST WINDS BELOW MOUNTAIN PASSES AND CANYONS. OFFSHORE FLOW WEAKENS ON MONDAY BUT FLOW REMAINS WEAK OFFSHORE THROUGH THURSDAY.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES.

EDDY CONTINUES OVER THE COASTAL WATERS BUT HAS MOVED FURTHER SOUTH WAS WAS CENTERED ABOUT 60 NM SOUTHWEST OF SAN CLEMENTE ISLAND. EDDY CONTINUES TO MAINTAIN A FAIRLY EXTENSIVE CLOUD SHIELD OVER THE COASTAL WATERS WITH SOME CLOUDS OVER THE COASTAL AND INLAND AREAS AS WELL. ACARS SOUNDINGS ARE NOT AVAILABLE THIS AFTERNOON BUT BASED ON RECENT PILOT REPORTS...MARINE LAYER DEPTH WAS AROUND 5500 FEET OVER THE AREA.

STRATOCU SHOULD CONTINUE TO FILL IN OVER THE AREA THROUGH THE EVENING AND REMAIN INTO SUNDAY MORNING. A SHORTWAVE TROUGH MOVING SOUTH FROM THE PACIFIC NORTHWEST WILL PASS THROUGH SOUTHERN CALIFORNIA ON SUNDAY. THIS SHORTWAVE WILL BE ANOTHER INSIDE SLIDER WITH LITTLE EFFECT ON THE AREA OTHER THAN TO BRING SOME HIGH CLOUDS. STRONG OFFSHORE FLOW IS EXPECTED TO DEVELOP BEHIND THIS SHORTWAVE BY SUNDAY AFTERNOON. THIS OFFSHORE FLOW WILL HAVE STRONG UPPER SUPPORT BEHIND THE SHORTWAVE TROUGH. EXPECT STRONG GUSTY WINDS TO DEVELOP THROUGH AND BELOW MOUNTAIN PASSES AND CANYONS BY SUNDAY AFTERNOON...ESPECIALLY BELOW THE CAJON PASS AND OVER THE SANTA ANA MOUNTAINS. WILL ISSUE A HIGH WIND WATCH FOR THESE AREAS BEGINNING 18Z SUNDAY AND CONTINUE THROUGH 02Z TUESDAY OR MONDAY EVENING. WILL ALSO ISSUE A WIND ADVISORY FOR ORANGE COUNTY COAST AND THE REMAINING MOUNTAIN AREAS FOR THE SAME PERIOD.

UPPER SUPPORT AND SURFACE GRADIENTS RELAX BY MONDAY EVENING AS THE RIDGE OVER THE EASTERN PACIFIC MOVES OVER THE COAST. WEAK OFFSHORE FLOW WILL CONTINUE OVER THE AREA THROUGH MOST OF THE WEEK BUT UPPER SUPPORT WILL BE LACKING FOR ANY SIGNIFICANT WIND AFTER MONDAY. HOWEVER...OFFSHORE FLOW WILL KEEP THE AREA DRY THROUGH THE PERIOD.

&&

.AVIATION... A COASTAL EDDY WILL CONTINUE THROUGH THE EVE AND BROKEN STRATUS CEILINGS WILL CONTINUE TO FORM IN AREAS NEAR THE COAST AND IN THE COASTAL VALLEYS. CEILINGS WILL BE AROUND 3500 FT THEN LOWER TO AROUND 1500-2000 FEET OVERNIGHT. OFFSHORE FLOW WILL DEVELOP SUN MORNING...CLEARING THE SKIES AND GENERATING STRONG OFFSHORE WINDS. MTN WAVES...TURBULENCE...WIND SHEAR AND ROTORS ARE ALL POSSIBLE IN THE LEE (COASTAL SIDE) OF THE MTN RANGES...ESPECIALLY AROUND ONT.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...

FIRE WEATHER WATCH SUNDAY MORNING THROUGH TUESDAY AFTERNOON FOR THE MOUNTAINS...INLAND VALLEYS AND COASTAL AREAS. SEE LAXRFWSGX.

HIGH WIND WATCH SUNDAY MORNING THROUGH MONDAY EVENING FOR THE INLAND EMPIRE AND SANTA ANA MOUNTAINS. WIND ADVISORY FOR SAME PERIOD FOR ORANGE COUNTY COAST AND REMAINING MOUNTAIN AREAS. SEE LAXNPWSGX.

&&

$$

PUBLIC............HORTON MARINE/AVIATION...MM

.NEAR TERM... 967 HPA SFC LOW NEAR ANTICOSTI ISLAND IN THE GULF OF ST LAWRENCE AS OF 18 UTC IS GRADUALLY FILLING AS 1031 HPA OVER OHIO PRESSES EAST. WINDS HAVE BEEN GENERALLY 20-25KT SUSTAINED GUSTING 30-35 KT TODAY AND ARE JUST BELOW WIND ADVISORY CRITERIA. WITH NO INDICATION THAT WINDS WILL INCREASE OVER CURRENT CONDITIONS NEXT FEW HOURS AND LATEST KEWR ACARS SHOWING LESS THAN 40 KT BELOW 5K FT...WE`LL BE DROPPING THE WIND ADVISORY.

OTHERWISE...WINDS GRADUALLY DECREASE OVERNIGHT, BUT WE DO NOT THEM TO DECOUPLE. THUS, HAVE RAISED MOS TEMPS OVER KFOK.

SKIES TO BECOME CLEAR AS SCT-FEW STRATO-CU DISSIPATE.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/... ONLY SUBTLE DIFFERENCES OVERALL IN NAM AND GFS...SO FOLLOWED A BLEND...THIS IS ALSO SUPPORTED BY THE 9Z SREF ENSEMBLE MEAN FIELDS.

HIGH PRESSURE AT THE SURFACE AND RIDGING ALOFT SHOULD KEEP THINGS DRY SUNDAY AND SUNDAY NIGHT. EVEN THOUGH 850 TEMPERATURES WARM ABOUT 6 DEGREES C FROM TODAY...STRONG SUBSIDENCE INVERSION UNDER SURFACE HIGH/RIDGE ALOFT WILL LIMIT AMOUNT OF MIXING AND ALLOW THE HIGH ON SUNDAY TO BE ONLY ABOUT A CATEGORY WARMER THAN TODAY. WEAK LOW LEVEL WARM ADVECTION AND INCREASING CLOUD COVER SUNDAY NIGHT IN RESPONSE TO THE WARM ADVECTION AND AN AREA OF LOW PRESSURE DEVELOPING NEAR THE CAROLINA COAST AND ONE APPROACHING FROM THE OHIO VALLEY WILL PROMOTE LOWS 4-8 DEGREES WARMER THAN TONIGHT...BUT STILL SLIGHTLY BELOW NORMAL AT MOST LOCATIONS. DO HAVE A SLIGHT CHANCE OF SNOW AFTER MIDNIGHT SUNDAY NIGHT OVER WESTERN 1/2 OF CWA TO REFLECT INCREASING LOW LEVEL ISENTROPIC LIFT THERE. TEMPERATURES FOR BOTH PERIODS ARE CONSISTENT WITH A BLEND OF MET/MAV/FWC MOS.

STRONGEST LOW PRESSURE SYSTEM ENDS UP BEING THE ONE DEVELOPING OFF THE CAROLINA COAST...AND IT AND ITS PRECIPITATION ENDS UP STAYING WELL TO OUR SOUTH MONDAY. DO MAINTAIN SLIGHT CHANCE POPS OVER WESTERN SECTIONS REFLECTING WEAK FORCING (THAT IS FALLING APART AS IT MOVES IN) FROM FADING LOW PRESSURE MOVING THROUGH PENNSYLVANIA TOWARDS NORTHEAST NEW JERSEY MONDAY. ONLY USED A BLEND OF MET/FWC GUIDANCE ON MONDAY FOR HIGHS AS MAV GUIDANCE SHOWED A LARGE RANGE OF TEMPERATURES (FROM 42 AT KTEB TO 29 AT KGON) REFLECTIVE OF A FRONT STALLED ACROSS THE REGION...THIS IS NOT EXPECTED TO BE THE CASE...SO THE GUIDANCE WAS DISCARDED IN THIS TIME FRAME.

INDEPENDENT OF THE LOWS...A FAIRLY POTENT 500 MB AND 700 MB SHORTWAVES WILL CROSS THE REGION MONDAY NIGHT. NAM IS A BIT MORE AGGRESSIVE WITH THESE FEATURES THAN THE GFS...BLEND USED RESULTS IN CHANCE OF SNOW SHOWERS MONDAY EVENING...THEN A SLIGHT CHANCE OF SNOW SHOWERS AFTER MIDNIGHT OVER THE EASTERN 1/2 OF THE CWA. MAV AND MET NUMBERS WERE FAIRLY SIMILAR FOR LOWS MONDAY NIGHT SO FOLLOWED A BLEND THERE.

HIGH PRESSURE RIDGES IN FROM THE WEST TUESDAY AS A THE 85H-5H TROUGH AXIS MOVES ACROSS THE REGION. RESULT WILL BE PARTLY TO MOSTLY CLOUDY SKY CONDITIONS WITH HIGHS SLIGHTLY BELOW NORMAL (BLEND OF MEX AND MEX ENSEMBLE MEAN GUIDANCE).

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... BASED EXTENDED ON 6Z GFS ENSEMBLE MEAN...WHICH WAS FAIRLY WELL SUPPORTED BY THE 6Z DGEX/12Z GFS AND 12Z CANADIAN GLOBAL. HIGH PRESSURE BUILDS IN WEDNESDAY...AND RETREATS TOWARDS THE CANADIAN MARITIME WEDNESDAY NIGHT. IT APPEARS AN AREA OF LOW PRESSURE WILL DEVELOP NEAR THE SOUTHERN MID ATLANTIC COAST THURSDAY MORNING...AND THEN LIFT NORTHEAST AND STRENGTHEN...BEING LOCATED NEAR NOVA SCOTIA BY 12Z FRIDAY...WITH THE LOW PASSING NEAR THE 70W/40N BENCH MARK THURSDAY EVENING AS IT DOES SO. IN RESPONSE TO THIS INTRODUCE A CHANCE OF SNOW WEDNESDAY NIGHT AND CONTINUE IT ON THURSDAY...THEN GO OVER TO A CHANCE OF SNOW SHOWERS THURSDAY NIGHT...WITH A SLIGHT CHANCE OF SNOW SHOWERS ON FRIDAY BEHIND THE SYSTEM. THE LONG TIME FRAME WITH POPS REFLECTS MORE UNCERTAINTY WITH TIMING OF THE SYSTEM...FEEL BEST CHANCE OF SNOW FOR NOW IS DURING THE DAY ON THURSDAY WITH SNOW SHOWERS AS THE SYSTEM PULLS AWAY THURSDAY EVENING. STILL TOO EARLY TO TELL...BUT THE POTENTIAL EXISTS WITH THIS SYSTEM FOR THE 1ST SIGNIFICANT SNOWFALL OF THE WINTER ACROSS AT LEAST PORTIONS OF THE TRI-STATE. TO EARLY TO PUT IN THE HWO OR ISSUE A STATEMENT...BUT WILL CONTINUE TO MONITOR. HIGH PRESSURE BUILDS IN FROM THE WEST FRIDAY INTO SATURDAY WITH A WEAK CLIPPER SYSTEM PASSING TO OUR NORTH ON SATURDAY AS WELL. EXPECT TEMPERATURES TO BE PRIMARILY BELOW NORMAL THROUGH THE PERIOD...CLOSE TO MEX ENSEMBLE MEAN NUMBERS.

&&

.AVIATION... LOW PRESSURE OVER THE GULF OF ST LAWRENCE IN CANADA IS FILLING SLOWLY AS HIGH PRESSURE FROM THE OHIO VALLEY BUILDS IN.

VFR THROUGH SUNDAY.

NW FLOW OF 25G35KT THIS AFTERNOON WILL PERSIST STEADY STATE THOUGH THE EVENING PUSH. WINDS THEN GRADUALLY DIMINISH OVERNIGHT UNDER CLEAR SKIES.

NO IMPACT FOR SUNDAY WITH SKC AND NW FLOW OF OF 10 TO 15 DIMINISHING TO LESS THAN 10 BY AFTERNOON.

BECOMING SMOOTH FOR GA ON SUNDAY AFTERNOON. CIRRUS MOVES FROM WEST IN THE AFTERNOON.

&&

.MARINE... STRONG AND GUSTY NORTHWESTERLY WINDS CONTINUE ACROSS THE FORECAST WATERS THIS EVENING AND INTO THE EARLY PART OF SUNDAY AS STRONG LOW PRESSURE OVER EASTERN CANADA MOVES EAST AND WEAKENS WHILE HIGH PRESSURE BUILDS IN FROM THE WEST. GALE FORCE WINDS WILL REMAIN OVER THE OCEAN WATERS THROUGH MUCH OF THE NIGHT WHILE OVER THE SOUND AND HARBOR WIND GUSTS WILL SUBSIDE TO SMALL CRAFT LATE TONIGHT. SUNDAY SMALL CRAFT WIND GUSTS WILL CONTINUE ON THE WATERS UNTIL LATE MORNING...SUBSIDING RATHER QUICKLY AS THE HIGH BUILDS OVER THE AREA WATERS.

TRANQUIL CONDITIONS WILL BE ON THE WATERS THROUGH WEDNESDAY AS WEAK LOW PRESSURE MOVES SOUTH OF THE WATERS MONDAY INTO MONDAY NIGHT. OTHERWISE HIGH PRESSURE WILL REMAIN OVER THE WATERS UNTIL THURSDAY. THURSDAY...LOW PRESSURE MOVES OUT OF THE GREAT LAKES AND ANOTHER LOW DEVELOPS OFF THE MID ATLANTIC AND MOVES NORTHEAST WHILE DEEPENING.

THE STRONG OFFSHORE WINDS COMBINED WITH LOW ASTRONOMICAL TIDES WERE CAUSING THE POTENTIAL FOR LOW WATER PROBLEM THE THIS AFTERNOON AND THIS EARLY EVENINGS HIGH TIDE CYCLE. TIDES ARE EXPECTED TO BE NEARLY TWO FEET BELOW ON THE OCEAN AND 2 TO 2 1/2 FEET BELOW ON THE SOUND. BY THE TIME OF THE NEXT LOW TIDE CYCLE TONIGHT AND EARLY SUNDAY MORNING...WINDS WILL HAVE SUBSIDED AND THE ASTRONOMICAL LOW TIDE WILL BE HIGHER.

&&

.HYDROLOGY... NO SIGNIFICANT PRECIPITATION IS EXPECTED ACROSS THE REGION UNTIL POSSIBLY NEXT WEDNESDAY NIGHT/THURSDAY...BUT THAT SHOULD FALL MAINLY (IF NOT ENTIRELY AS SNOW)...AND THUS HAVE MINIMAL HYDROLOGICAL IMPACT IN THE SHORT TO MEDIUM RANGE.

&&

.OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...LOW WATER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ338- 350-353-355. SMALL CRAFT ADVISORY FROM 3 AM TO 10 AM EST SUNDAY FOR ANZ330- 335-338-355. GALE WARNING UNTIL 3 AM EST SUNDAY FOR ANZ330-335-338-355. LOW WATER ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ330-335. SMALL CRAFT ADVISORY FROM 6 AM TO 10 AM EST SUNDAY FOR ANZ350- 353. GALE WARNING UNTIL 6 AM EST SUNDAY FOR ANZ350-353.

&&

$$

NEAR TERM/AVIATION...JST SHORT/LONG TERM AND HYDROLOGY...MALOIT MARINE...MET

.NEAR TERM (TODAY)... NO SIGNIFICANT CHANGES TO FORECAST AT THIS TIME. MONITORING LAKE EFFECT SNOW BANDS OVER WESTERN CT. ADDED IN SW- AND CONFINED FLURRIES TO EASTERN SECTIONS. IMPRESSIVE EARLIER MORNING SNOW BAND DROPPED A BAND OF 1/2 TO 1 INCH OF SNOW FROM NE NJ TO SW NASSAU. SEE RR8 PRODUCTS FOR AMOUNTS. CONFIRMED THAT CENTRAL PARK WAS ONLY 0.1"

WINDS PICKING UP AND SOLID ADVISORY CONDITIONS EXPECTED. LOOKING AT LATEST RUC AND ACARS DATA...DO NOT SEE REACHING WIND WARNING (50 KT) LEVELS.

FROM PREVIOUS...OTHERWISE...STRONG LOW PRESSURE CONTINUES TO TRACK NORTHWARD THROUGH THE CANADIAN MARITIMES EARLY THIS MORNING. SYSTEM HAS DEEPENED TO NEAR 965 MB AS PER THE NAM/WRF FCST. THIS LOW WILL COMBINE WITH A 1033 MB HIGH BUILDING INTO THE OHIO VALLEY TO PRODUCE A TIGHT PRESSURE GRADIENT ACROSS THE REGION TODAY. AN ARCTIC COLD FRONT...MOVING INTO NRN NY STATE AS OF 06Z...WILL MOVE SOUTHWARD AND CROSS THE FCST AREA EARLY THIS AFTERNOON. THIS WILL BRING IN A SURGE OF MUCH COLDER AIR...WITH 850 MB TEMPS DROPPING TO AROUND -16C. MAIN FCST PROBLEM TODAY WILL BE STRONG WINDS. SPEEDS WILL BEGIN TO INCREASE THIS MORNING AS THE GRADIENT TIGHTENS AND MIXING INCREASES...THEN WINDS WILL CRANK FURTHER EARLY THIS AFTERNOON THROUGH THIS EVENING AS THE ARCTIC FRONT MOVES THROUGH WITH AN ASSOCIATED INCREASE IN LOW LEVEL WINDS AND STRONG CAA. EXPECTING SUSTAINED WINDS OF 25-35 MPH WITH GUSTS OF 40-50 MPH DURING THIS PERIOD. WIND ADVISORY WILL REMAIN IN EFFECT FOR THE ENTIRE CWA FROM MID MORNING THROUGH THE EVENING.

INCLUDED SLIGHT CHANCE OF SNOW FLURRIES FOR THE ENTIRE AREA TODAY AS BUFKIT SOUNDINGS INDICATE SOME MOISTURE IN THE SNOW GROWTH REGION... AND ARCTIC FRONTAL PASSAGE COMBINED WITH SOME PVA MAY MANAGE TO SQUEEZE OUT THE FLAKES. TEMPS WILL BE QUITE CHILLY WITH A SMALL DIURNAL RANGE AS THE COLDER AIR WILL BE MOVING IN THIS AFTERNOON. HIGHS WILL RANGE FROM THE UPPER 20S TO LOWER 30S. WENT WITH THE COLDER FWC NUMBERS AS THE MAV APPEARED TO BE TOO WARM FOR THE ARCTIC AIRMASS. SKIES WILL STAY PARTLY CLOUDY THROUGH MUCH OF THE DAY...THEN CLEAR OUT QUICKLY MID-LATE AFTERNOON AS DRIER AIR MOVES IN BEHIND THE FRONT. &&

.SHORT TERM (TONIGHT THROUGH MONDAY)... WINDY CONDITIONS WILL CONTINUE THROUGH THE EVENING WITH WIND ADV STILL POSTED...THEN WINDS DIMINISH AFTER MIDNIGHT AS LOW PRES OVER THE CANADIAN MARITIMES RISES TO ~985MB AND HIGH PRES MOVES INTO THE CENTRAL APPALACHIANS. WINDS WILL STILL REMAIN AT 10 TO 20 MPH WITH GUSTS UP TO 30 MPH LATE TONIGHT. THESE WINDS WILL COMBINE WITH LOW TEMPERATURES RANGING FROM 15-20 IN/AROUND NYC AND 10-15 ELSEWHERE TO PRODUCE LOW WIND CHILL VALUES OF AROUND 5 ABOVE IN AND AROUND NYC... AND AROUND ZERO ELSEWHERE.

HIGH PRES SLOWLY MOVES ACROSS THE AREA ON SUN WITH CLEAR SKIES. NW WINDS WILL KEEP HIGH TEMPS ON SUN NOT MUCH WARMER THAN SAT. DEVELOPING LOW PRES OVER THE SOUTHEAST UNITED STATES WILL DRIFT N TOWARDS THE MID-ATLANTIC...BUT HIGH PRES OVER THE AREA SHOULD SUPPRESS THIS LOW FROM MOVING TOO FAR N. THE HIGH WILL MOVE OFFSHORE SUN NIGHT...THEN A WEAK TROUGH WILL MOVE THROUGH THE REGION ON MON...POSSIBLY PRODUCING SOME LIGHT SNOW SHOWERS. WILL KEEP SLIGHT CHC POPS IN THE FCST.

LOWS SUN NIGHT WILL BE IN THE MID 20S IN/AROUND NYC...LOWER 20S AT COASTAL LOCATIONS...AND IN THE TEENS IN OUTLYING LOCATIONS. HIGHS ON MON WILL BE MILDER WITH HIGHS IN THE MID TO UPPER 30S....RETURNING CLOSER TO THE SEASONAL AVERAGE. &&

.LONG TERM (MONDAY NIGHT THROUGH FRIDAY)... NO CHANGES AT THIS TIME...BUT STILL LOOKING AS SYSTEM FOR LATE THURSDAY.

SRN STREAM SYSTEM SHOULD BE TRACKING WELL OFFSHORE AND TO THE SOUTH OF THE AREA MON NIGHT...WITH NO EFFECT ON THE LOCAL REGION EXPECTED. MODEL GUIDANCE CONTINUES TO BRING A SERIES OF WEAK NRN STREAM SHORTWAVES THROUGH THE BROAD UPPER TROF ACROSS THE NE ON TUE... BUT THESE TYPE OF SYSTEMS TYPICALLY STRUGGLE TO PRODUCE SIGNIFICANT SNOW ACROSS THE FCST AREA AND HAVE KEPT THE FCST DRY. TEMPS WILL REMAIN NEAR TO SLIGHTLY BELOW NORMAL.

A COLD FRONT WILL MOVE INTO THE AREA BY LATE WED/EARLY THU...AND THIS WILL BE THE LEADING EDGE OF A DEEP UPPER LEVEL TROUGH AND POLAR AIRMASS WHICH WILL BRING COLDER AIR TO THE AREA FOR THE 2ND HALF OF THE WEEK. THIS FRONT...ALONG WITH A SERIES OF MID AND UPPER LEVEL DISTURBANCES THAT WILL ROTATE THROUGH THE BASE OF TROUGH...MAY PRODUCE SCATTERED SNOW SHOWERS ACROSS THE AREA. THE CHILLY WX WILL CONTINUE...WITH HIGH TEMPERATURES ONLY IN THE UPPER 20S TO LOWER 30S ON THU AND FRI.

20/00Z MODEL GUIDANCE IS SPLIT ON THE IDEA OF A MAJOR EAST COAST LOW FOR THE LATER PART OF NEXT WEEK. GFS AMPLIFIES THE ERN TROF...PHASES WITH THE SRN STREAM AND DEVELOPS A FULL-SCALE NOREASTER BOMB WHICH TRACKS JUST WEST OF THE 40/70 BENCHMARK ON THU...WHILE THE GFS ENS MEAN SHOWS A SOMEWHAT WEAKER COAST HUGGER. GGEM IS SIMILAR BUT NOT AS STRONG AS THE OPER GFS. UKMET/ECMWF HAVE A DIFFERENT UPPER PATTERN WITH THE 5H CUTOFF REMAINING IN PLACE OVER THE DESERT SW WHICH RESULTS IN A BROADER NE UPPER TROF WITH THE NRN STREAM REMAINING DOMINANT. THIS PREVENTS ANY SIGNIFICANT COASTAL DEVELOPMENT. WITH CONFIDENCE LOW...WILL NOT MAKE ANY CHANGES TO THE EXISTING THU/FRI FCST AT THIS TIME. &&

.AVIATION... DEEPENING LOW PRESSURE OVER THE CANADIAN MARITIMES KEEPS STRONG NORTHWESTERLY FLOW THOUGH THIS EVENING. HIGH PRESSURE AND LIGHT WINDS FOR SUNDAY.

SCT TO BKN STRATO-CUMULUS CLOUDS EXPECTED AT TIMES TODAY WITH SCT SNOW SHOWERS OR FLURRIES MAINLY NORTH AND EAST OF NYC. STRONG WEST TO NORTHWEST WINDS ANTICIPATED TODAY WITH TIGHT PRESSURE GRADIENT AND STRONG COLD AIR ADVECTION PRODUCING STEEP LOW LEVEL LAPSE RATES. THE REASON FOR THIS IS BECAUSE LOCAL AREA REMAINS CAUGHT BETWEEN STRONG LOW PRESSURE OVER THE CANADIAN MARITIMES AND BUILDING HIGH PRESSURE OVER THE CENTRAL PART OF THE COUNTRY. THE HIGHEST GRADIENT IS FORECAST FROM NYC E ACROSS CT AND LONG ISLAND. THE PREVAILING WIND DIR WILL RANGE FROM 290 TO 310 DEGS. SUSTAINED SPEEDS WILL INCREASE THIS MORNING FROM AROUND 15 KTS TO AROUND 20 KTS WITH GUSTS 40 TO 45 KT FROM NYC EAST. WINDS GRADUALLY DIMINISH TONIGHT AS GRADIENT RELAXES SOMEWHAT. &&

.MARINE... NO CHANGES AT THIS TIME...WAS CONSIDERING STORM FORCE WINDS...BUT SOLID GALE CONDITIONS LOOK TO COVER IT. STRONG LOW PRESSURE IN SOUTHEAST CANADA WILL REMAIN NEARLY STATIONARY TODAY...THEN MOVE E AND WEAKEN BY SUN. THE PRESSURE GRADIENT BETWEEN THIS LOW AND HIGH PRESSURE MOVING IN FROM THE WEST ALONG WITH STEEP LOW LEVEL LAPSE RATES OVER RELATIVELY WARM WATER WILL CONTINUE TO PRODUCE GALE FORCE WINDS TODAY AND INTO TONIGHT. THE STRONGEST WINDS ARE EXPECTED TO OCCUR THIS AFTERNOON AND EVENING VIA A REINFORCING SHOT OF CAA...WITH SUSTAINED WINDS 25-35 KT AND GUSTS 40-45 KT. WINDS DIMINISH QUICKLY LATE TONIGHT AND SUNDAY...WITH RAPIDLY IMPROVING CONDITIONS. WINDS DROP TO AROUND 10 KTS BY SUNDAY AFTERNOON...QUITE A DIFFERENCE.

CONDITIONS SHOULD BECOME FAVORABLE FOR SOME LIGHT FREEZING SPRAY ON EASTERN LONG ISLAND SOUND AND OCEAN ZONES LATE TODAY INTO THIS EVENING WITH BORDERLINE WATER TEMPS. SUSTAINED WINDS OVER 25 KT AND SEAS OVER 5 FT ARE EXPECTED. STRONG CAA SHOULD HELP WATER TEMPS DROP TO THE MID 40S ON THE OCEAN AND LOWER 40S ON THE SOUND.

THE STRONG OFFSHORE FLOW COMBINED WITH LOW ASTRONOMICAL LOW TIDES DUE TO THE NEW MOON MAY ALSO RESULT IN LOW WATER PROBLEMS WITH THE LOW TIDE CYCLES TODAY AND TONIGHT. GFS STORM SURGE GUIDANCE CONSISTENT WITH PREVIOUS RUNS AND STILL INDICATES LOW TIDES OF 2.5 TO 3.5 FT MLLW TODAY AND TONIGHT...WITH IMPROVEMENT SUNDAY.

CONDITIONS IMPROVE AS MENTIONED SUNDAY AND REMAIN RELATIVELY TRANQUIL INTO THE EARLY PART OF THE WEEK. &&

.HYDROLOGY... DRY WEATHER EXPECTED THROUGH SUNDAY EVENING. SLIGHT CHC POPS REMAIN IN THE FCST FOR LATE SUN NIGHT AND MON WHEN A WEAK NRN STREAM S/W WILL BE AFFECTING THE AREA. ALSO A REMOTE POSSIBILITY THAT A SRN STREAM LOW MAY MOVE NE ALONG THE COAST...BUT ALMOST ALL MODEL GUIDANCE KEEPS THIS SYSTEM SUPPRESSED WELL OFFSHORE TO THE SOUTH. IN ANY CASE...PRECIP AMOUNTS DURING THIS PERIOD WILL BE LIGHT AT BEST... LIKELY LESS THAN 1/10 OF AN INCH LIQUID EQUIV...AND IT IS MOST LIKELY THAT WE WILL REMAIN DRY. &&

.OKX WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY FROM 9 AM THIS MORNING TO 1 AM EST SUNDAY FOR CTZ005>012. NY...WIND ADVISORY FROM 9 AM THIS MORNING TO 1 AM EST SUNDAY FOR NYZ067>081. NJ...WIND ADVISORY FROM 9 AM THIS MORNING TO 1 AM EST SUNDAY FOR NJZ002>006-011. MARINE...LOW WATER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR ANZ338-350-353-355. GALE WARNING UNTIL 1 AM EST SUNDAY FOR ANZ330-335-338. LOW WATER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM EST SUNDAY FOR ANZ330-335. GALE WARNING UNTIL 3 AM EST SUNDAY FOR ANZ355. GALE WARNING UNTIL 6 AM EST SUNDAY FOR ANZ350-353. &&

$$

UPDATE...TONGUE

.AVIATION...

LAKE EFFECT SNOW SHOWERS HAVE DIMINISHED SUBSTANTIALLY...AND THE AREA IS ON THE CUSP OF STRATUS/STRATO-CU OVER SOUTHWEST LOWER. SO IT APPEARS THE FORECAST OVERNIGHT WILL BE PRETTY MUCH SCATTERED LOWER VFR CEILINGS WILL OCCASIONAL "INTRUSIONS" OF STRATUS FROM THE WEST TO BRING BROKEN CEILINGS CLOSER TO THE MVFR RANGE. THIS SCENARIO WILL CONTINUE INTO SATURDAY MORNING...WITH DIURNAL INSTABILITY PROBABLY LEADING TO AN OVERALL INCREASE IN CLOUDS BY MIDDAY.

&&

.PREV DISCUSSION...ISSUED AT 613 PM

UPDATE...

UPDATED TO HONE IN ON HEAVIER SNOW BANDS THAT WILL BRING POSSIBLE ACCUMULATIONS OF AN INCH OR TWO ALONG I-96/I-94. THIS ACTIVITY IS SURVIVING THE TRIP FROM LAKE MICHIGAN NICELY...AND SHOULD REMAIN LARGELY INTACT UNTIL A SURFACE TROUGH MOVES THROUGH THE AREA BY BETWEEN 8 AND 10 PM. OTHER THAN THIS "CORRIDOR"...ACCUMULATIONS SHOULD REMAIN BELOW AN INCH FOR THE MOST PART...WITH MOST AREAS RECEIVING NO MORE THAN A DUSTING THE REST OF THE EVENING.

PREV DISCUSSION...ISSUED AT 356 PM

SHORT TERM...TONIGHT AND SATURDAY

SCATTERED TO NUMEROUS SNOW SHOWER ACTIVITY TO CONTINUE AT LEAST INTO THE EVENING HOURS AS UPPER LEVEL TROUGH AXIS PUSHES INTO THE CENTRAL GREAT LAKES REGION. WITH THE LACK OF ORGANIZED BANDING (ALTHOUGH THERE IS A HINT OF AN I-94 BAND) AND INVERSION HEIGHTS AROUND 6000 FEET AT THE PRESENT TIME (PER DTW TAMDAR)...ACCUMULATIONS SHOULD BE LESS THAN AN INCH FOR THE MOST PART. WITH SOME SEMBLANCE OF AN I-94 BAND...WASHTENAW COUNTY STANDS TO SEE THE MOST...PROBABLY AN INCH OR SLIGHTLY BETTER.

BOTH 12Z GFS/NAM INDICATING SATURATION AT 850 MB WITH TEMPS FALLING TO -18C BY 6Z SATURDAY. INVERSION HEIGHTS THEN FALL BELOW 5000 FEET LATE TONIGHT. HOWEVER...WITH THE AIRMASS AS COLD AS IT IS...MOISTURE AT 925 MB COULD BE ENOUGH TO PRODUCE A FEW FLURRIES ON SATURDAY. SURFACE RIDGE WILL SLOWLY BUILD INTO SOUTHEAST MICHIGAN DURING SATURDAY AND ARRIVE BY EVENING...WITH CLEARING TAKING PLACE OVER THE CWA. JUST NOT SURE HOW QUICK THE CLEARING WILL OCCUR...AS WE COULD EASILY START THE DAY OUT MOSTLY CLOUDY WITH MOISTURE TRAPPED UNDERNEATH THE INVERSION. OR...WE COULD START OUT WITH A FAIR AMOUNT OF SUN...CU UP LATE MORNING...BEFORE MIXING OUT THE REMAINING LOW LEVEL MOISTURE DURING THE AFTERNOON. EITHER WAY...THE DAY SHOULD AVERAGE OUT TO AT LEAST PARTLY SUNNY. BLENDED THE NEW MAV GUIDANCE AND PREVIOUSLY FORECASTED TEMPS FOR TONIGHT AND TOMORROW.

LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

SATURDAY NIGHT THROUGH MONDAY...

MODELS QUITE SIMILAR. SURFACE RIDGE ON TAP TO PASS THROUGH SATURDAY NIGHT...BEFORE MOVING OFF TO THE EAST SUNDAY. ON ITS HEELS...A BROAD DIFFUSE INVERTED TROUGH TO PROGRESS EAST ACROSS THE AREA SUNDAY THROUGH SUNDAY NIGHT. AT 500 MB...SHORTWAVE RIDGE BUILDING IN SATURDAY NIGHT...BEFORE IT GETS DISPLACED EAST SUNDAY AS A SHORTWAVE TROUGH FROM THE SOUTHWEST SHEARS NORTHEAST INTO THE SOUTHERN LAKES REGION AND CONTINUES EAST SUNDAY NIGHT. MORE MID LEVEL TROUGHINESS APPROACHING MONDAY FROM THE WEST.

850 TO 500 MB MOISTURE RAPIDLY INCREASES SUNDAY AS PER GOOD MODEL CONSENSUS...THEN TREND TOWARD SLIGHT LESSENING SUNDAY NIGHT AND MONDAY. AT 925 MB...DRIER SATURDAY NIGHT IN PRESENCE OF LOW LEVEL RIDGE...MOISTENING BY SUNDAY AFTERNOON AND CONTINUING MOIST THROUGH MONDAY. GFS...NAM...AND LOCAL WRFHEMI ALL SHOW 700 MB THETA E RIDGE NUDGING SOUTHERN LOWER MI SUNDAY.

A FEW UBAR/SEC OF OMEGA ASCENT SEEN SUNDAY AFTERNOON AS PER MODEL CONSENSUS...THOUGH STRONGER GFS CLOSER TO 10 UBAR/SEC ASCENT DESPITE LOWER MOS POPS. 850 TO 500 MB QVECTOR CONVERGENCE QUITE ROBUST SUNDAY AFTERNOON...OTHERWISE LITTLE TO NONE FOR THIS PERIOD. DURING SUNDAY...TOO...MAINLY IN THE AFTERNOON...MODELS ADVERTISE SLIGHT SURFACE WIND CONVERGENCE...MODEST 850 TO 700 MB FRONTOGENESIS AND DEFORMATION...AND PRETTY GOOD 250 MB DIVERGENCE/850 MB CONVERGENCE COUPLING. FINALLY...A FEW UBAR/SEC ASCENT SEEN BY SUNDAY AFTERNOON ON 280K SURFACE...AS CONDENSATION PRESSURE DEFICITS LOWER TO AROUND 10 MB IN MOST AREAS.

AFTER A DRY SATURDAY NIGHT...DYNAMICS AND MOISTURE JUSTIFY LIKELY POPS SUNDAY...WHEN SNOWFALL AMOUNTS FROM AROUND AN INCH TO 2 INCHES ARE ANTICIPATED...WITH HEAVIEST AMOUNTS EXPECTED NEAR THE SOUTHERN BORDER.

AFTER MONDAY...

SURFACE LOW LEVEL CYCLONIC FLOW EXPECTED TO PREVAIL EARLY IN WEEK...AHEAD OF A CLIPPER LIKE SYSTEM ARRIVING MID WEEK. CONSIDERABLE MODEL TIMING VARIATION SEEN WITH THIS MID WEEK SYSTEM AMONG MODELS AND GFS ENSEMBLE MEMBERS. AT ANY RATE...MODELS ARE IN OVERALL AGREEMENT...WITH THE MID WEEK SYSTEM INTRODUCING A FRESH REINFORCEMENT OF ARCTIC AIR BEHIND IT. 12Z MEX TEMPERATURES FOR THURSDAY ARE ABOUT 10 DEGREES F COLDER THAN THE 00Z GUIDANCE... REFLECTING A FASTER PROGRESSION AS PER THE 12Z GFS. HAVE LOWERED TEMPERATURES A FEW DEGREES FOR THURSDAY...BUT THEY MAY NEED EVEN MORE LOWERING IF LATER RUNS CONTINUE THIS TREND.

AT 500 MB...A LOOSELY PHASED HIGH AMPLITUDE SHORTWAVE TROUGH EXPECTED TO SLOWLY ADVANCE EAST ACROSS THE AREA EARLY IN WEEK...WITH COLD NORTHWEST FLOW IN ITS WAKE PERTURBED BY STRONG MID WEEK IMPULSE.

AS IN PREVIOUS FORECAST...CHANCE OF SNOW OR SNOW SHOWERS EACH DAY IS HARD TO DISPUTE IN THIS TYPE OF PATTERN...GIVEN LAKE EFFECT COMBINED WITH SYNOPTIC SCALE BOOST FROM TIME TO TIME.

&&

.DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...GALE WARNING...ALL OPEN WATERS UNTIL 11 AM SATURDAY.

SMALL CRAFT ADVISORY...LHZ422 UNTIL 7 AM SATURDAY.

SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 7 PM SATURDAY.

SMALL CRAFT ADVISORY...LHZ421 UNTIL 11 AM SATURDAY.

LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ460 UNTIL 7 AM SATURDAY.

MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...UNTIL 7 AM SATURDAY.

&&

$$

AVIATION.....DG UPDATE.......DG SHORT TERM...SF LONG TERM....DWD

YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

.UPDATE...HAVE ISSUED A WINTER WEATHER ADVISORY FOR ZONES 9-11 EFFECTIVE THROUGH 11 AM MST MON. ADJUSTED POPS ACCORDINGLY AND LOWERED SOME TEMPS OVERNIGHT. 40

&&

.PREV DISCUSSION...202 PM MST SUN JAN 21 2007... 20Z SFC ANALYSIS SHOWS LOW PRESSURE CENTERED OVER S CENTRAL CO WITH A COLD FRONT DRAPED SW THROUGH NW NM INTO SOUTHERN AZ. 1022MB HIGH PRES AREA IS NOSING DOWN THE LEE OF THE ROCKIES EAST OF DENVER FORCING A COLD FRONT SOUTH INTO NE NM. WV/IR SAT IMAGERY SHOWS AN UPPER LEVEL LOW MOVING SOUTH THRU AZ WITH A SHEARED UPPER TROUGH OVER CENTRAL CO EXTENDING EAST INTO THE UPPER MIDWEST. THE LATEST 400-200MB AIRCRAFT DATA INDICATES A 110-130 KNOT JET OVER EASTERN NV DIVING SOUTH BEHIND THE UPPER LOW. RADAR TRENDS THIS AFTERNOON SHOW SN BREAKING OUT OVER EASTERN AZ AS WELL AS BEHIND THE FRONT OVER SE CO.

12Z MREF H5 HEIGHT PATTERN IN GOOD AGREEMENT WITH 15Z SREF THAT 3-4 SIGMA UPPER LEVEL LOW WILL CONTINUE TO MOVE SOUTH THRU MON AFT TO A POSITION OVER FAR NE SONORA...WITH LITTLE ENSEMBLE SPREAD. 12Z NAM AND GFS SOLNS IN GOOD AGREEMENT WITH THE DETAILS OF THE DEVELOPING WINTER STORM FOR SOUTHWEST CORNER OF NM. SIDED WITH 12Z GFS ON MODEL DETAILS WITH HPC COLLABORATION AND WWD SNOW AMOUNT GRAPHICS. UPPER DIVERGENCE WILL INCREASE OVERNIGHT ACROSS THE WESTERN HALF OF NM AS THE UPPER LOW DIVES SOUTH. THE COLD FRONT OVER SE CO WILL ALSO ADVANCE SOUTHWEST ACROSS THE NE PLAINS INTO THE CENTRAL VALLEYS AFTER DARK. THIS WILL ALLOW A DECENT CANYON WIND TO AFFECT USUAL LOCATIONS ACROSS ABQ AND SET UP A CONVERGENCE ZONE ALONG THE CONTINENTAL DIVIDE OVERNIGHT. PLENTIFUL LOW LEVEL MOISTURE... UPSLOPE FLOW INTO THE WESTERN MTNS AND GILA REGION...MODERATE UPPER DIVERGENCE...ALONG WITH IDEAL DENDRITIC SNOW GROWTH WILL YIELD AVERAGE OF 5-10 INCHES OF SNOW WITH LOCALLY HIGHER AMOUNTS UP TO 15 INCHES ALONG THE CONTINENTAL DIVIDE. HENCE WILL UPGRADE ZONE 8 AND 14 TO WARNING AND BUFFER WITH A SNOW ADV FOR ZONES 15-16-17-26. ABQ SITS IN A UNIQUE LOCATION AS EAST WINDS WILL LIKELY BLOW SNOW BEYOND WEST MESA HOWEVER WEAK OVERTOPPING MAY DEPOSIT SOME SNOW IN THE FOOTHILLS. LEFT SANDIA...MANZANOS...AND ABQ OUT OF THE ADVISORY ATTM. WILL LIKELY SEE A LARGE SNOWFALL GRADIENT OVER EASTERN CIBOLA AND WESTERN SOCORRO COUNTIES.

MODEL SOLNS DIVERGE CONSIDERABLY BEYOND TUESDAY WITH POSITION OF UPPER LOW. GFS TAKES STORM SYSTEM WELL SOUTH INTO CHIHUAHUA WHILE NAM SPINS UPPER LOW ALONG NM/MEXICO BORDER. BOTH MODELS LIFT SYSTEM NORTHWARD THRU NM LATE IN THE WEEK WITH ANOTHER POSSIBLE WINTER STORM. TIMING AND INTENSITY WITH THIS IS SIGNIFICANTLY DIFFERENT FROM MODEL TO MODEL AND RUN TO RUN. LEFT SLIGHT CHANCE POPS IN THE EXTENDED AND KEPT PARTLY-MOSTLY CLOUDY SKIES ACROSS THE SOUTH.

&&

.ABQ WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR THE FOLLOWING ZONES...NMZ008-014.

SNOW ADVISORY UNTIL 5 PM MST MONDAY FOR THE FOLLOWING ZONES... NMZ015>017-026.

WINTER WEATHER ADVISORY UNTIL 11 AM MST MONDAY FOR THE FOLLOWING ZONES...NMZ009>011.

&&

$$

GUYER

.SHORT TERM(TONIGHT-TUE)... THE LAKE EFFECT SNOWS HAVE NEARLY DIMINISHED PER RADAR AND SATELLITE PICTURES. ACARS/TAMDAR SOUNDINGS SHOW THAT THE INVERSION IS UNDER 4000 FT AND THE ANTICYCLONE TO THE WEST IS WINNING OUT. STILL SOME LOWER VSBYS IN THE SNOWBELT PER OBSERVATIONS...BUT AM THINKING THAT CONDITIONS SHOULD RAPIDLY IMPROVE AS THE INVERSION CRASHES AND THE RIDGE CONTINUES TO BUILD EAST. WILL THEREFORE EXPIRE ALL WARNINGS...BUT GO OUT WITH SNOW ENDING WORDING WITH LOCALLY AN ADDITIONAL INCH OR TWO IN THE SNOWBELT. OTHERWISE...THE NEXT WEATHER MAKER WILL BE THE QUICK MOVING SOUTHERN STREAM SYSTEM FORECAST TO MOVE INTO THE AREA SUNDAY. THIS WILL BE A QUICK HITTER...BUT MAY CAUSE A BRIEF PERIOD OF MODERATE SNOW ESPECIALLY ACROSS THE WESTERN AND SOUTHERN 2/3 PART OF THE FORECAST AREA SUNDAY AFTN. LATEST MODEL RUNS ARE IN GOOD AGREEMENT IN THE EVOLUTION OF THE SYSTEM...WITH THE NAM COMING AROUND TO A FASTER SOLN LIKE THE GFS SUGGESTED YESTERDAY. AS THE SYSTEM MOVES OUT OF THE SRN PLAINS TONIGHT...EXPECT THE UPPER LOW TO OPEN UP AND QUICKLY SHEAR OFF TO THE NORTHEAST. THIS WILL CAUSE A WEAK OPEN SFC LOW TO MOVE THRU THE OH VLY LATE SUNDAY INTO SUNDAY NIGHT. CURRENT THINKING IS THAT A SNOW WILL START QUICKLY LATE SUNDAY MORNING OVER THE FINDLAY AREA AND QUICKLY SPREAD EAST TO NE OH/NW PA BY LATE AFTN/EARLY EVENING. ALTHOUGH THE PERIOD OF SNOW WILL BE RELATIVELY SHORT /ON THE ORDER OF 6 HOURS/...THE INTENSITY OF THE SNOW MAY BE MODERATE AT TIMES SUNDAY AFTERNOON AS THERE IS AN INDICATION OF A MODERATE TO STRONG FRONTOGENESIS/FRONTOLYSIS COUPLET WHICH RESEARCH SUGGESTS MAY BE A FAIRLY ACTIVE PART OF THE FRONTAL ZONE. THIS ACTIVE FRONTAL ZONE COMBINED WITH SOME NEGATIVE EPV ABOVE THE AREA OF F-GEN INDICATIVE OF WEAK STATIC STABILITY MAY ALLOW FOR A PERIOD OF LOCALLY 1 INCH PER HOUR SYNOPTIC TYPE SNOW. MODELS SHOW THAT THIS AREA WILL MOVE EAST QUICKLY...BUT NOT BEFORE THE NAM FCSTS A QUICK 1-3 INCHES OF SYNOPTIC SNOW ACROSS MUCH OF THE AREA ESPECIALLY SOUTH AND WEST OF CLE TO CAK LINE SUN AFTN. WITH THIS ACTIVE FRONTAL ZONE...LATER SHIFTS WILL HAVE TO MONITOR FOR SLIGHTLY HIGHER SNOW AMOUNTS...BUT FORTUNATELY THE SPEED OF THE SYSTEM MAY LIMIT AMOUNTS. THE FRONTOGENESIS WEAKENS LATE SUN AFTN INTO SUN NIGHT AS IT MOVES EAST AS THE UPPER JET QUICKLY MOVES EAST. WILL CONTINUE WITH LIKELY POPS ACROSS THE EAST IN THE EVENING. OTHERWISE...A DRY SLOT QUICKLY MOVES INTO THE AREA. MOISTURE IS DEEPER WITH THIS RUN COMPARED TO PREVIOUS RUNS...SO ALHTOUGH THERE IS VERY LITTLE UPWARD MOTION THERE WILL LIKELY BE SOME FLURRIES OR A CHANCE OF LIGHT SNOW ACROSS THE ENTIRE AREA SUN NIGHT. THE CLOUD TOPS ARE ALSO A LITTLE COLDER ESPECIALLY ACROSS THE NORTH...SO FREEZING DRIZZLE SUN NIGHT NOT AS MUCH OF A THREAT. HOWEVER...CLOUD TOPS A LITTLE WARMER ACROSS THE FAR SOUTH SO ICE CRYSTAL FORMATION NOT AS LIKELY. WILL THEREFORE INTRODUCE FREEZING DRIZZLE ACROSS THE FAR SOUTH SUNDAY NIGHT. WILL CONTINUE WITH CHC OF SNOW ON MONDAY ALTHOUGH IT LOOKS LIKE ANY SNOW WILL BE MINIMAL. MAY BE A LITTLE ENHANCEMENT IN THE SNOWBELT BUT 850MB TEMPS ONLY AROUND -10C SO MARGINAL FOR LES. WEAK WARM ADVECTION TUE AHEAD OF THE WED SYSTEM WILL ALLOW FOR A SMALL CHANCE OF SNOW...BUT AGAIN IT DOES NOT LOOK SIGNIFICANT.

WILL GO ON THE COLDER END OF GUIDANCE FOR THE NEXT COUPLE OF DAYS...ESPECIALLY NE DUE TO SNOW COVER.

&&

.LONG TERM(WED-SAT)... THE EXTENDED MODELS CONTINUE TO SHOW A -NAO PATTERN...WHICH USUALLY MEANS COLDER THAN NORMAL TEMPS FOR THE LOWER LAKES AND EASTERN U.S. IN GENERAL. THE 00Z AND 06Z RUNS OF THE GFS SHOWS THIS TO BE TRUE WITH AN ARCTIC EXPRESS TYPE SCENARIO AT 500MB WITH LONGITUDINAL FLOW FROM THE ARCTIC CIRCLE BY THE END OF THE WORK WEEK. THE GFS SHOWS THE COLDEST AIR OF THE YEAR THU INTO FRI WITH LESS THAN -20C AT 850MB. CANADIAN MODEL IN GENERAL AGREEMENT ALTHOUGH NOT AS COLD. ECMWF IS THE OUTLIER SOLN WITH LESS AMPLIFICATION OF THE FLOW ACROSS NOAM. HPC LIKES A 06Z ENSEMBLE MEAN SOLN WHICH TRENDS TOWARD THE OPNL GFS ALTHOUGH NOT AS COLD. WITH THAT IN MIND...THE CLIPPER SYSTEM ON WED WILL SPREAD LIGHT SNOW ACROSS THE ENTIRE REGION. WILL CONTINUE CHANCE POPS FOR LIGHT SNOW WED. THIS WILL OPEN THE DOOR FOR THE DEEP TROUGH TO DIG ACROSS THE LAKES WITH THU AND FRI SEEING PLENTY OF SNOW SHOWERS WITH LAKE EFFECT SNOW CERTAINLY A CONCERN. WILL CONTINUE WITH CHANCE POPS FOR THE ENTIRE AREA WITH SNOW LIKELY IN THE NORTHEAST. IF THE GFS IS TRUE...THE STRONGLY CYCLONIC FLOW WITH A SERIES OF UPPER DISTURBANCES MOVING ACROSS LAKE ERIE MAY ALLOW FOR A SIGNIFICANT LAKE EFFECT EVENT FOR NORTHEAST OHIO THU AND FRI BUT THIS IS CERTAINLY TOO FAR IN ADVANCE TO BE TALKING ABOUT ANY ACCUMULATIONS. OTHERWISE...BY SATURDAY HIGH PRES BUILDS INTO THE AREA. WILL GO WITH A DRY FCST ON SATURDAY. TEMPS WILL REMAIN BELOW NORMAL THRU THE PERIOD. MAY SEE TEMPS STRUGGLE TO GET OUT OF THE TEENS THU AND FRI IF THE GFS IS TRUE. FOR NOW...WILL LOWER TEMPS INTO THE LOWER 20S THU AND FRI.

&&

.AVIATION(18Z-18Z)... ONGOING LES DOWNWIND OF LAKES ERIE HURON AND ST CLAIR GRADUALLY COMING TO AN END HOWEVER STILL SEEING PERIODS OF IFR SNOW AT ERI/YNG AT THE MOMENT WHILE FURTHER WEST...SKIES ARE CLEAR. HIGH PRESSURE TO THE WEST WILL CONTINUE TO BUILD IN THIS AFTERNOON AND WILL GO WITH VFR CONDITIONS WEST OF CLEVELAND THIS AFTERNOON AND EVENING. WILL HAVE SNOW TAPERING OFF IN THE EAST BEFORE 00Z...BRIEF PERIODS OF MVFR SNOW WILL OCCUR THROUGH THE REMAINDER OF THE AFTERNOON THEN GIVE WAY TO VFR CIGS/VSBYS OVERNIGHT. HIGH CLOUDS WILL STREAM IN AFTER MIDNIGHT AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WITH SNOW POSSIBLE AFTER SUNRISE IN THE WEST AND PROBABLY NOT UNTIL AFTER THE END OF THE FORECAST PERIOD FURTHER EAST. &&

.CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE.

&&

$$

SHORT TERM...MRD LONG TERM...MRD AVIATION...LEINS

.SHORT TERM /TODAY THROUGH THURSDAY/...

COUNTY WARNING AREA(CWA) STAYS IN BROAD NORTHWEST FLOW AT 500 MB THROUGH THURSDAY. SHORT WAVE TROFS MOVE THROUGH THE AREA TONIGHT...ON WEDNESDAY AFTERNOON AND EVENING...AND ON THURSDAY MORNING.

MSAS LIFTED INDEX ANALYSIS AND SURFACE OBSERVATIONS SHOW THE LOCATION OF THE WEDGE FROM RIGHT ALONG THE BLUE RIDGE INTO THE EASTERN COUNTIES OF THE CWA. THE WEDGE IS FORECAST TO ERODE BETWEEN BY 18Z TODAY. SURFACE AND LOW LEVEL WINDS BECOMING WEST THIS MORNING. LITTLE OF ANY DRIZZLE LEFT NOW AND TEMPERATURES WEST OF THE BLUE RIDGE AND IN NORTH CAROLINA AND EXTREME SOUTHERN VIRGINIA ARE RISING ABOVE 32 SO ADVISORY WILL BE CANCELLED AT 5AM.

BUT...WITH WEST WIND FOG IN SOUTHEAST WEST VIRGINIA WILL BE SLOW TO DISSIPATE. MAY BE BREAKS IN THE CLOUDS EAST OF THE BLUE RIDGE THIS AFTERNOON. BUT WITHOUT MUCH SUN...WITH ICE/SLEET ON THE GROUND...AND WITH COLD AIR ADVECTION BY THE END OF THE DAY...WARMING WILL BE SLOW. WENT BELOW COLDEST GUIDANCE FOR HIGH TEMPERATURES TODAY.

FOR TONIGHT MODELS ARE SHOWING SOME FRONTOGENESIS AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY WITH THE SHORT WAVE TONIGHT. 850 MB TEMPERATURES DROP BACK WELL BELOW ZERO WITH 850 MB WINDS IN UP TO 45 KNOTS. SHORT WAVE COMBINED WITH LOW LEVEL MOISTURE AND FAVORABLE UPSLOPE WINDS WILL PRODUCE SNOW SHOWERS IN THE WESTERN CWA THROUGH TUESDAY MORNING. AIRMASS DRIES OUT ON TUESDAY WITH LITTLE CLOUDS COVER LEFT BY THE END OF THE DAY.

ON WEDNESDAY AND WEDNESDAY NIGHT THERE IS Q-VECTOR FORCING WITH THE SECOND SHORT WAVE. PLENTY OF MOISTURE MOVES BACK INTO THE AREA SO THE MOUNTAINS WILL AGAIN HAVE A CHANCE OF PRECIPITATION. AT THE SURFACE LOW PRESSURE THAT DEVELOPS IN THE OHIO RIVER VALLEY WILL MOVE INTO THE SOUTHERN APPALACHIANS BY WEDNESDAY AFTERNOON. BEHIND THIS LOW AND ASSOCIATED COLD FRONT ANOTHER SURGE OF COLD AIR MOVES INTO THE REGION.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...

NO CHANGES AT THIS TIME

&&

.AVIATION /10Z-06Z/...

PRECIPITATION AXIS DRIFTING TO THE SOUTHEAST THIS EVENING. THIS WILL DECREASE PRECIPITATION INTENSITIES ACROSS THE AREA. HOWEVER...THETA-E MOISTURE AXIS AND WEAK WAVE ALOFT TO KEEP DRIZZLE IN THE AREA THROUGH 10Z MONDAY. STILL SOME AREAS ALONG AND EAST OF THE BLUE RIDGE WITH TEMPERATURES AT OR BELOW FREEZING...THEREFORE ADDITIONAL GLAZING FROM FREEZING DRIZZLE IS POSSIBLE. OTHER THAN THE LIGHT PRECIPITATION...IFR CEILINGS WILL BE A HAZARD FOR AIRCRAFT THROUGH SUNRISE WITH MOUNTAIN RIDGES OBSCURED. THESE LOW CLOUDS WILL LINGER IN THE AREA UNTIL MID MORNING...THEN CONDITIONS TO SLOWLY IMPROVE TO VFR AS WEST WINDS HELP SCOUR LOW LEVEL MOISTURE IN THE AFTERNOON.

&&

.RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE.

&&

$$

SHORT TERM...AMS LONG TERM...AMS AVIATION...RCS

.AVIATION /05Z-24Z/...

PRECIPITATION AXIS DRIFTING TO THE SOUTHEAST THIS EVENING. THIS WILL DECREASE PRECIPITATION INTENSITIES ACROSS THE AREA. HOWEVER...THETA-E MOISTURE AXIS AND WEAK WAVE ALOFT TO KEEP DRIZZLE IN THE AREA THROUGH 10Z MONDAY. STILL SOME AREAS ALONG AND EAST OF THE BLUE RIDGE WITH TEMPERATURES AT OR BELOW FREEZING...THEREFORE ADDITIONAL GLAZING FROM FREEZING DRIZZLE IS POSSIBLE. OTHER THAN THE LIGHT PRECIPITATION...IFR CEILINGS WILL BE A HAZARD FOR AIRCRAFT THROUGH SUNRISE WITH MOUNTAIN RIDGES OBSCURED. THESE LOW CLOUDS WILL LINGER IN THE AREA UNTIL MID MORNING...THEN CONDITIONS TO SLOWLY IMPROVE TO VFR AS WEST WINDS HELP SCOUR LOW LEVEL MOISTURE IN THE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 1210 AM EST MON JAN 22 2007/

UPDATE...

WILL BE UPDATING ZONES TO REMOVE MIDNIGHT WORDING. EXPECT ONLY STEADY TEMPERATURES OR A ONE OR TWO DEGREE RISE OVERNIGHT. NO CHANGES TO THE ADVISORY AT THIS TIME.

PREV DISCUSSION... /ISSUED 853 PM EST SUN JAN 21 2007/

UPDATE...

UPDATED THE WARNINGS AND DROPPED THOSE TO WINTER WX ADVISORY...EXCEPT CLEARED AREAS WHERE TEMPS ARE AT OR ABOVE FREEZING OVERNIGHT. STILL EXPECTING LIGHT ICING FROM -FZRA/FZDZ...ESPECIALLY EAST OF THE BLUE RIDGE TOWARD LYH OVERNIGHT.

SHORT TERM /REST OF TONIGHT/...

WARM AIR HAS MADE INROADS INTO THE TYPICAL NON-WEDGED LOCATIONS...THAT IS BLF-6V3-VJI-TNB. THIS WARM AIR WILL CONTINUE TO WORK ITS WAY INTO SW VA OVERNIGHT...BUT TEMPS FURTHER NORTH AND EAST WILL REMAIN AT OR BELOW FREEZING. LOW PRESSURE MOVING OFF THE NC COAST 12Z MONDAY WILL END ANY MEASURABLE PRECIP WITH LINGERING DRIZZLE IN SE WV. SOUNDINGS SHOW THAT PRECIP SHOULD CHANGE TO MORE OF A DRIZZLE/FREEZING DRIZZLE SCENARIO AFT 06Z...EARLY FOR LOCATIONS FURTHER WEST. MADE TWEAKS TO TEMPS BASED ON CURRENT CONDITIONS AND ADJUSTED TOWARD MAV MOS USING SOME CORRECTION UP OR DOWN BASED ON WHERE THE WEDGE WILL REMAIN.

PREV DISCUSSION... /ISSUED 643 PM EST SUN JAN 21 2007/

AVIATION /00Z-24Z/...

STORM SYSTEM OVER THE SOUTH WILL BEGIN SHIFTING EAST AND OUT OF THE AREA LATE TONIGHT. WINTRY PRECIP WILL HANG AROUND FOR MOST OF THE NIGHT THIS EVENING...ESPECIALLY EAST OF THE BLUE RIDGE TOWARD LYH. CIGS WILL BE THE MAIN AVIATION CONCERN AS THEY LOWER BELOW 1000 FT AT ALL TAF SITES. VLIFR/IFR CONDITIONS WILL DOMINATE THE OVERNIGHT...WITH ROA/LYH/DAN SEEING CIGS IMPROVE AFT 12Z MON. FREEZING PRECIP WILL TAPER TO DRIZZLE BEFORE 12Z. ENOUGH MIXING MONDAY AFTERNOON WILL BRING VFR CONDITIONS TO THE PIEDMONT AND ROA VALLEY...WITH SE WV IMPROVING JUST TO LOW MVFR AT BEST.

PREV DISCUSSION... /ISSUED 306 PM EST SUN JAN 21 2007/

SHORT TERM /TONIGHT/...

UPWARD VERTICAL MOTION FIELDS WILL GRADUALLY WEAKEN EARLY TONIGHT AS WARM AIR ADVECTION AND ASSOCIATED ISENTROPIC LIFT MOVES OFF TO THE NORTH AND EAST...LEAVING BLACKSBURG FORECAST AREA IN MAINLY NEUTRAL ADVECTION ZONE UNTIL LATER TONIGHT WHEN SHORT WAVE TROF PASSES THROUGH AREA AND WEAK COLD AIR ADVECTION BEGINS FROM NORTHWEST TO SOUTHEAST.

LARGE AREA OF FREEZING RAIN...WITH SOME ICE PELLETS PERSISTING ACROSS NORTHERN AREAS...WILL GRADUALLY DIMINISH EARLY TONIGHT...AND TRANSITION OVER TO MORE OF A LIGHT FREEZING DRIZZLE OR DRIZZLE WITH PASSAGE OF WAVE AS MID AND UPPER LEVEL MOISTURE IS LOST...LEAVING SHALLOW MOISTURE POOL TRAPPED BELOW INVERSION LAYER.

LIMITED SURFACE MIXING UNDER COOL WEDGE TOPPED BY WARM ADVECTION WILL RESULT IN LITTLE OR NO TEMPERATURE DECREASE TONIGHT...WITH EVEN A SLOW RISE EXPECTED ACROSS THE NORTHWEST (LATE) WHEN SURFACE MIXING BEGINS IN ASSOCIATION WITH WEAK COOL ADVECTION AND INCREASING PRESSURE GRADIENT BEHIND SURFACE LOW...AND ACROSS THE PIEDMONT WHERE TEMPERATURES ALOFT WILL BE THE WARMEST.

CONSIDERING THE VERY SLUGGISH TEMPERATURE RECOVERY UNDER THE COOL WEDGE...SOME SHELTERED AREAS AND HIGHER RIDGES WILL NOT EXPERIENCE ABOVE FREEZING TEMPERATURES UNTIL LATE TONIGHT...POSSIBLY NOT UNTIL AROUND OR SHORTLY AFTER DAYBREAK. THEREFORE...WILL CONTINUE WITH EXISTING WARNINGS AND ADVISORIES WITH NO SIGNIFICANT CHANGES TEMPORALLY OR SPATIALLY.

LONG TERM /MONDAY THROUGH SUNDAY/...

BY MONDAY MORNING...THE BULK OF THE MOISTURE ASSOCIATED WITH THE EXITING SYSTEM SHOULD HAVE ALSO EXITED THE REGION. WHAT LOOKS TO REMAIN WILL SOME SHALLOW LOW CLOUDS ACROSS THE AREA...ESPECIALLY OVER SE WV AND NEIGHBORING SW VA. ALSO IN THIS AREA...LINGERING PATCHY PRECIPITATION SHOULD CONTINUE THROUGH THE DAY. WITH ANY SATURATED LAYERS BELOW -10 C LACKING...EXPECT THE PRECIPITATION TO BE IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE...DEPENDING UPON THE LOCAL SURFACE TEMPERATURE. DESPITE THE CLOUD COVER...GOOD WARM AIR ADVECTION SHOULD PROVIDE FOR TEMPERATURES REACHING VALUES AT...OR SLIGHTLY ABOVE...SEASONAL NORMALS.

HEADING INTO MID-WEEK...THE OVERALL SYNOPTIC PATTERN WILL BE DOMINATED BY A LOW PRESSURE SYSTEM THAT LOOKS TO PARK ITSELF OVER QUEBEC...ALLOWING FOR A PREDOMINATELY NORTHWEST FLOW AND COLD AIR ADVECTION...INTO THE REGION. THIS PATTERN WILL KEEP RESIDUAL LOW LEVEL MOISTURE BEING LIFTED UPSLOPE ACROSS SE WV...AND WITH COOLING TEMPERATURES IN THE LOW LEVELS...WE SHOULD START TO SEE BETTER POTENTIAL FOR ICE CRYSTAL GROWTH SOMETIME LATE MONDAY EVENING...AND THEN THROUGH THE REST OF MONDAY NIGHT INTO THE DAY ON TUESDAY. LITTLE ACCUMULATION OF SNOW IS EXPECTED.

ALSO AS PART OF THIS OVERALL SYNOPTIC PATTERN WILL BE A CUT-OFF LOW OVER THE THE NORTHERN STATES OF MEXICO AND A PREVAILING SUB-TROPICAL JET PROGRESSING FROM THE WESTERN PORTION OF THE GULF OF MEXICO ACROSS FLORIDA.

THERE HAD BEEN SOME CONCERN FOR THE TIME PERIOD OF WEDNESDAY THROUGH THURSDAY NIGHT OF A SYSTEM MOVING THROUGH THE NORTHERN STREAM BRANCH PHASING WITH...OR COME CLOSE TO PHASING WITH...A SOUTHERN STREAM BRANCH AND PROVIDING FOR A SUBSTANTIAL WINTER SYSTEM FOR THE AREA DURING THE TIME PERIOD. THE TREND TODAY HAS BEEN FOR THESE SYSTEMS TO STAY LESS-PHASED THAN EARLIER RUNS SUGGESTED THEY MIGHT COME CLOSE TO DOING. ACCORDINGLY...THE PREFERRED GUIDANCE FROM HPC HAS LOWERED CHANCES OF PRECIPITATION WEDNESDAY THROUGH THURSDAY NIGHT AS COMPARED TO ITS PREVIOUS SOLUTION. THIS PRECIPITATION WILL PRIMARILY BE IN THE FORM OF SNOW FROM NORTHWEST FLOW UPSLOPE FORCING OVER SE WV AND NEIGHBORING SW VA AND FAR NW NC. ALTHOUGH DURING THE AFTERNOON WEDNESDAY...IT MAY START AS A MIX OF RAIN OR SNOW DEPENDING UPON LOCAL TEMPERATURES. LITTLE IF ANY PRECIPITATION IS EXPECTED EAST OF THE BLUE RIDGE.

AFTER A SMALL BREAK IN THE ACTIVITY FRIDAY AND FRIDAY NIGHT...ANOTHER NORTHWEST FLOW DISTURBANCE WILL BRING A RETURN OF SCATTERED SNOW SHOWERS TO THE MOUNTAINS FOR THE WEEKEND.

AVIATION /20Z-18Z/...

EXPECT TO SEE ALL BLACKSBURG TERMINAL FORECAST POINTS (ROANOKE...LYNCHBURG...DANVILLE...BLUEFIELD...LEWISBURG) TO SEE GRADUAL REDUCTION TO INSTRUMENT FLIGHT RULE RESTRICTIONS IN CEILING..AND PERHAPS VISIBILITY...AS LOWER ATMOSPHERE SATURATES DUE TO PRECIPITATION. WARM AIR ALOFT NOW SUFFICIENTLY DEEP THAT ALL PRECIPITATION HAS CHANGED OVER TO FREEZING RAIN...AND THIS LIKELY TO CONTINUE UNTIL AT LEAST EARLY TONIGHT BEFORE BEST AREA OF LIFT AND MOISTURE MOVES OFF TO THE EAST.

WILL BEGIN TO SEE GRADUAL IMPROVEMENT BACK TO MARGINAL FLIGHT RULE RESTRICTIONS IN CEILING...WITH NO VISIBILITY RESTRICTION...BY OR SHORTLY AFTER DAYBREAK MONDAY AS DOWNSLOPE WINDS BEGIN TO IMPACT AREAS EAST OF THE BLUE RIDGE. FURTHER WEST AT BLUEFIELD AND LEWISBURG...INCREASING UPSLOPE CONDITIONS WILL LIKELY DELAY IMPROVEMENT IN WEATHER UNTIL MID-LATE MORNING.

&&

.RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR VAZ011>020-022>024-032>035-043>047-058-059.

NC...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NCZ002>006.

WV...WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR WVZ043>045.

&&

$$

UPDATE... AVIATION...RCS

.UPDATE... AREAS OF DRIZZLE OR -SHRA ARE CONTINUING OVER THE LMK CWA THIS MORNING BASED ON LOCAL RADARS. ACARS SOUNDINGS AND LATEST RUC INDICATE THAT PTYPE SHOULD REMAIN LIQUID TODAY...WITH ATMOS ABOVE 800MB/-7C REMAINING DRY. WILL INCLUDE AREAS OF DRIZZLE WITH A SLIGHT CHANCE OF RAIN SHOWERS GIVEN COVERAGE OF PRECIP ON RADAR CURRENTLY AND VSBYS NEAR 1SM AT FTK. IT`S CONCEIVABLE THAT WITHIN SPOTS OF HIGHER REFLECTIVITY/DEEPER SATURATION...THERE COULD BE A BRIEF RA/SN SHOWER...SOMETHING TO WATCH TODAY.

INCOMING 12Z NAM IS SHOWING STEEP LOW LEVEL LAPSE RATES CONTINUING INTO THE EVENING HOURS...SO HAVE EXTENDED DRIZZLE/SHRA INTO THE EVENING ACROSS THE CWA. MAY SEE A TRANSITION TO FLURRIES AS LOW LEVELS COOL. TEMPS TODAY WILL BE A CHALLENGE. EXTENSIVE CLOUD COVER AND WEAK COLD ADVECTION SHOULD KEEP READINGS NEARLY STEADY.

UPDATED FCST WILL BE OUT BY 11 AM EST.

CS

&&

.PREV DISCUSSION... /ISSUED 844 AM EST MON JAN 22 2007/

UPDATE... QUICK UPDATE TO ACCOUNT FOR PRECIP DEVELOPING FROM NEAR SDF/FTK OVER INTO SRN INDIANA AND SOUTH TO NEAR BWG. WILL REFER TO THIS AS PATCHY DRIZZLE. PTYPE BASED ON LATEST ACARS/RUC SOUNDINGS SHOULD REMAIN LIQUID (DRIZZLE) AS CRITICAL ICE CRYSTAL LAYER IS DRY. REST OF FCST UNCHANGED AT THIS TIME.

CS

PREV DISCUSSION... /ISSUED 316 AM EST MON JAN 22 2007/

SHORT TERM (TODAY AND TONIGHT)...

SHORT TERM MODELS SHOW VERY LITTLE DISAGREEMENT THRU THE NEXT 24 HRS...WILL LEAN TOWARDS A BLEND OF THE 21Z SREF AND THE 00Z GFS FOR THE FORECAST PERIOD. ONLY SIGNIFICANT FORECAST PROBLEM IS DEALING WITH TEMPS AND CLOUDS.

MODEST POSITIVE TILT TROUGH ACROSS THE WESTERN GREAT LAKES INTO THE PLAINS...WITH CLOSED LOW ACROSS THE GADSDEN PURCHASE REGION OF THE DESERT SOUTHWEST AND WEAK SE CONUS RIDGING. SFC HI PRESSURE SITS JUST TO THE WEST OF THE REGION...PRODUCING WNW WINDS. TROUGH SHIFTS EAST FROM THE PLAINS INTO THE MS VALLEY BY AFTERNOON...BRINGING IN SLIGHTLY COLDER AIR ALOFT AT 850 MB...850 TEMPS DROPPING TO AROUND -8C. TROUGH PUSHES ON THROUGH THE MID OHIO VALLEY DURING THE OVERNIGHT PERIOD...AS SFC RIDGING NUDGES EAST IN THE REGION WITH SLIGHT 850 MB WARMING TOWARDS -4C AS THE TROUGH PUSHES EAST BY 12Z TUES.

TIME SERIES OF BWG/LEX/SDF EACH SHOW SIGNIFICANT INVERSION TRAPPING MOISTURE BELOW 850 MB...WITH SFC TO 850 MB RH AVG AROUND 90-95 PERCENT THROUGH 12Z TUES. ABOVE THE 850 MB LAYER THE ATMS IS MUCH DRIER AND WARMER WITH RH AROUND 15-20 PERCENT THROUGHOUT MUCH OF THE COLUMN...AND TEMPS WARMING IN THE WSW FLOW AROUND 750 TO 700 MB TO 0C. BEFORE COOLING AS THE FLOW WEAKENS OVERNIGHT. SO WILL KEEP THE CLOUDY SKIES THROUGH THE ENTIRE PERIOD...WEAK LIFT SEEN JUST ABOVE THE MOISTURE DURING THE AFTERNOON AND WILL HAVE DRIZZLE IN AROUND NOON THRU 5PM.

THE NGMMOS HAS BEEN VERY INCONSISTENT AND JUMPY THE LAST 3 RUNS SO WILL DISCOUNT...WILL LEAN TOWARDS A BLEND OF THE MET/MAV MOS THIS AFTERNOON. EACH OF THE TWO HAS SHOWED A TREND OF ABOUT 1 DEGREE COOLER FOR THE AFTERNOON HIGHS...EASILY EXPLAINABLE DUE TO THE CLOUDS CREATING LESS HEATING. WILL GO A DEGREE OR TWO WARMER FOR OVERNIGHT LOWS THAN USING A STRAIGHT BLEND OF THE TWO ALSO DUE TO THE CLOUDS.

SCHOTT

LONG-TERM (TUESDAY THROUGH SUNDAY)...

THE LONG TERM PERIOD IS STILL CHARACTERIZED BY THE PERSISTENT MEAN RIDGE ALONG OR A LITTLE WEST OF THE WEST COAST OF THE US AND WESTERN CANADA. EARLY IN THE PERIOD ANOTHER CUTOFF LOW DEVELOPS OVER THE SOUTHWESTERN U.S. INTO NORTHWEST MEXICO THAT COULD IMPACT OUR REGION OVER THE WEEKEND. AT THE SAME TIME...A STRONG SHORT WAVE MOVING INTO NORTHWEST CANADA TO THE SOUTHEAST OF AK...BRIEFLY FLATTENS THE WESTERN CANADA RIDGE AND THEN DIGS SOUTHEAST INTO THE SOUTHERN HUDSON BAY REGION AND IS FOLLOWED BY A SERIES OF OTHER SHORT WAVES THAT PROMISE TO KEEP THIS NORTHERN STREAM AS THE CONTROLLING WEATHER MAKER FOR OUR REGION BEFORE BREAKING DOWN A BIT OVER NEXT WEEKEND.

DURING THE WEDNESDAY-THURSDAY TIME FRAME THIS FIRST CLIPPER LIKE SYSTEM BRINGS ANOTHER SURGE OF ARCTIC AIR SOUTHWARD INTO THE REGION. THIS COULD LEAD TO A PERIOD OF SNOW SHOWERS AND/OR FLURRIES FOR A TIME DURING THE ABOVE MENTIONED COUPLE OF DAYS. THIS IS MORE OR LESS IN LINE WITH OUR CURRENT FCST.

OVER THE WEEKEND THE NORTHERN STREAM IS MERGED BY THE REMNANTS OF THE SOUTHWESTERN CUTOFF AND LEADS TO ANOTHER CHC FOR SOME RAIN OR SNOW. THIS COULD BE ANOTHER SIMILAR SCENARIO TO THIS PAST WEEKEND. BOTH THE ECMWF AND GFS SHOW A SIMILAR TREND BUT WITH SOME SIGNIFICANT TIMING DIFFERENCES...THIS WILL HAVE TO BE WATCHED CLOSELY.

ONLY REAL CHANGES TO THE CURRENT FCSTS WERE SOME MINOR TWEAKS WITH THE HOURLY AND MAX AND MIN TEMPS FOR BETTER CONSISTENCY WITH THE SURROUNDING FA`S. --21

&&

.LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. &&

$$

.UPDATE... QUICK UPDATE TO ACCOUNT FOR PRECIP DEVELOPING FROM NEAR SDF/FTK OVER INTO SRN INDIANA AND SOUTH TO NEAR BWG. WILL REFER TO THIS AS PATCHY DRIZZLE. PTYPE BASED ON LATEST ACARS/RUC SOUNDINGS SHOULD REMAIN LIQUID (DRIZZLE) AS CRITICAL ICE CRYSTAL LAYER IS DRY. REST OF FCST UNCHANGED AT THIS TIME.

CS

&&

.PREV DISCUSSION... /ISSUED 316 AM EST MON JAN 22 2007/

SHORT TERM (TODAY AND TONIGHT)...

SHORT TERM MODELS SHOW VERY LITTLE DISAGREEMENT THRU THE NEXT 24 HRS...WILL LEAN TOWARDS A BLEND OF THE 21Z SREF AND THE 00Z GFS FOR THE FORECAST PERIOD. ONLY SIGNIFICANT FORECAST PROBLEM IS DEALING WITH TEMPS AND CLOUDS.

MODEST POSITIVE TILT TROUGH ACROSS THE WESTERN GREAT LAKES INTO THE PLAINS...WITH CLOSED LOW ACROSS THE GADSDEN PURCHASE REGION OF THE DESERT SOUTHWEST AND WEAK SE CONUS RIDGING. SFC HI PRESSURE SITS JUST TO THE WEST OF THE REGION...PRODUCING WNW WINDS. TROUGH SHIFTS EAST FROM THE PLAINS INTO THE MS VALLEY BY AFTERNOON...BRINGING IN SLIGHTLY COLDER AIR ALOFT AT 850 MB...850 TEMPS DROPPING TO AROUND -8C. TROUGH PUSHES ON THROUGH THE MID OHIO VALLEY DURING THE OVERNIGHT PERIOD...AS SFC RIDGING NUDGES EAST IN THE REGION WITH SLIGHT 850 MB WARMING TOWARDS -4C AS THE TROUGH PUSHES EAST BY 12Z TUES.

TIME SERIES OF BWG/LEX/SDF EACH SHOW SIGNIFICANT INVERSION TRAPPING MOISTURE BELOW 850 MB...WITH SFC TO 850 MB RH AVG AROUND 90-95 PERCENT THROUGH 12Z TUES. ABOVE THE 850 MB LAYER THE ATMS IS MUCH DRIER AND WARMER WITH RH AROUND 15-20 PERCENT THROUGHOUT MUCH OF THE COLUMN...AND TEMPS WARMING IN THE WSW FLOW AROUND 750 TO 700 MB TO 0C. BEFORE COOLING AS THE FLOW WEAKENS OVERNIGHT. SO WILL KEEP THE CLOUDY SKIES THROUGH THE ENTIRE PERIOD...WEAK LIFT SEEN JUST ABOVE THE MOISTURE DURING THE AFTERNOON AND WILL HAVE DRIZZLE IN AROUND NOON THRU 5PM.

THE NGMMOS HAS BEEN VERY INCONSISTENT AND JUMPY THE LAST 3 RUNS SO WILL DISCOUNT...WILL LEAN TOWARDS A BLEND OF THE MET/MAV MOS THIS AFTERNOON. EACH OF THE TWO HAS SHOWED A TREND OF ABOUT 1 DEGREE COOLER FOR THE AFTERNOON HIGHS...EASILY EXPLAINABLE DUE TO THE CLOUDS CREATING LESS HEATING. WILL GO A DEGREE OR TWO WARMER FOR OVERNIGHT LOWS THAN USING A STRAIGHT BLEND OF THE TWO ALSO DUE TO THE CLOUDS.

SCHOTT

LONG-TERM (TUESDAY THROUGH SUNDAY)...

THE LONG TERM PERIOD IS STILL CHARACTERIZED BY THE PERSISTENT MEAN RIDGE ALONG OR A LITTLE WEST OF THE WEST COAST OF THE US AND WESTERN CANADA. EARLY IN THE PERIOD ANOTHER CUTOFF LOW DEVELOPS OVER THE SOUTHWESTERN U.S. INTO NORTHWEST MEXICO THAT COULD IMPACT OUR REGION OVER THE WEEKEND. AT THE SAME TIME...A STRONG SHORT WAVE MOVING INTO NORTHWEST CANADA TO THE SOUTHEAST OF AK...BRIEFLY FLATTENS THE WESTERN CANADA RIDGE AND THEN DIGS SOUTHEAST INTO THE SOUTHERN HUDSON BAY REGION AND IS FOLLOWED BY A SERIES OF OTHER SHORT WAVES THAT PROMISE TO KEEP THIS NORTHERN STREAM AS THE CONTROLLING WEATHER MAKER FOR OUR REGION BEFORE BREAKING DOWN A BIT OVER NEXT WEEKEND.

DURING THE WEDNESDAY-THURSDAY TIME FRAME THIS FIRST CLIPPER LIKE SYSTEM BRINGS ANOTHER SURGE OF ARCTIC AIR SOUTHWARD INTO THE REGION. THIS COULD LEAD TO A PERIOD OF SNOW SHOWERS AND/OR FLURRIES FOR A TIME DURING THE ABOVE MENTIONED COUPLE OF DAYS. THIS IS MORE OR LESS IN LINE WITH OUR CURRENT FCST.

OVER THE WEEKEND THE NORTHERN STREAM IS MERGED BY THE REMNANTS OF THE SOUTHWESTERN CUTOFF AND LEADS TO ANOTHER CHC FOR SOME RAIN OR SNOW. THIS COULD BE ANOTHER SIMILAR SCENARIO TO THIS PAST WEEKEND. BOTH THE ECMWF AND GFS SHOW A SIMILAR TREND BUT WITH SOME SIGNIFICANT TIMING DIFFERENCES...THIS WILL HAVE TO BE WATCHED CLOSELY.

ONLY REAL CHANGES TO THE CURRENT FCSTS WERE SOME MINOR TWEAKS WITH THE HOURLY AND MAX AND MIN TEMPS FOR BETTER CONSISTENCY WITH THE SURROUNDING FA`S. --21

&&

.LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. &&

$$

.UPDATE... SURFACE TROUGH CURRENTLY FM SE LK SUPERIOR INTO N LK MICHIGAN. AHEAD OF TROUGH IS SYNOPTIC LIGHT SNOW/FLURRIES. BEHIND TROUGH...WNW WINDS AND MOISTURE TO AROUND H9 WITH TEMPS AT H9 NEAR -10C IS JUST ENOUGH TO SUPPORT LIGHT LK EFFECT SNOW SHOWERS. INCREASED POPS AHEAD OF TROUGH THROUGH EARLY AFTN...THEN DRYING IN THE H9-H8 LAYER AS SEEN ON UPSTREAM RAOBS AND TAMDAR SOUNDINGS SHOULD DIMINISH THE SNOW. WNW WINDS BACKING TO SW WILL EVENTUALLY PUSH MOST LK EFFECT OVR KEWEENAW BY LATE AFTN...WITH A FEW FLURRIES OR DRY WX ELSEWHERE. SOUNDINGS INDICATE SOME POTENTIAL FOR FREEZING DRIZZLE LATE THIS AFTN INTO THE EVENING AS MOIST LAYER IS MOST SHALLOW AND TEMPS AT TOP OF MOIST LAYER ARE BARELY -8C. DEEP MOISTURE IS ALREADY DEPARTING FAR WEST CWA AND THUS FAR NO FREEZING DRIZZLE OR FLURRIES. CURRENTLY...SFC DEWPOINT DEPRESSIONS AROUND 5F SO LOOKS TOO DRY IN LOWEST LAYER FOR THE DRIZZLE. UPSLOPE COMPONENT TO WINDS MAY EVENTUALLY OFFSET THIS LATER TODAY. HOWEVER...12Z GFS AND LOCAL HIGH RES WRF SOUNDINGS ARE EVEN DRIER AND WOULD SUGGEST NO PCPN OCCURS DURING THE EVENING. WILL CONTINUE TO INVESTIGATE DURING THE AFTN...BUT FOR NOW DID NOT MAKE MAJOR CHANGES TO GOING GRIDS.

SHORTWAVE AND SFC TROUGH OVR NORTHERN MANITOBA WILL DROP SE AND ACROSS LK SUPERIOR BY LATE TONIGHT...REACHING N UPR MI BY 12Z TUE. SW/W THEN EVENTUALLY NW FLOW FAVORS KEWEENAW FOR MOST SNOW SHOWERS TONIGHT. CONVERGENCE AND DEEPER MOISTURE TO ENHANCE LK EFFECT SETUP WITH OVERALL MARGINAL INSTABILITY (DLT T/S TO INVERSION TOP AROUND 13C) DOES NOT ARRIVE TIL LATER TONIGHT AND 12Z SOUNDINGS ARE A BIT DRIER WITH THE H9-H8 MOISTURE THAN PREVIOUSLY SHOWN. SO...DELAYED LIKELY POPS ON KEWEENAW TIL MIDNIGHT.

&&

.DISCUSSION (ISSUED AT 515 AM EST)... UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW IN SOUTHERN AZ WITH A CORRESPONDING TROUGH FROM THE DESERT SW TO THE NORTHERN PLAINS AND INTO THE UPPER GREAT LAKES WITH RIDGING IN THE PACIFIC NW AND ALSO ACROSS THE SE.

NAM SHOWING THE 500 MB PATTERN AMPLIFYING WITH THE 500 MB RIDGE BUILDING INTO THE ROCKIES AND THE TROUGH IN THE EAST DEEPENING WITH NW-SE FLOW MAINTAINED ACROSS THE AREA IN THE UPPER LEVELS.

NAM SHOWING SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING ACROSS THE AREA THIS AFTERNOON THROUGH TONIGHT WITH SOME MOISTURE AVAILABLE TONIGHT. NAM SHOWS MOISTURE ON ISENTROPIC SURFACES FROM I280K-I295K MOVING THROUGH WHICH IS IN THE MID LEVELS OF THE ATMOSPHERE...BUT LIFT REMAINS MOSTLY TO THE NORTH OF THE CWA TONIGHT AND THEN MOISTURE MOVES OUT ON TUE TO THE SOUTH OF THE AREA. GFS SHOWS ABOUT THE SAME THING ON ITS I280K-I290K SURFACES WITH LIFT STAYING MOSTLY TO THE NORTH OF THE AREA AND MOISTURE MOVING OUT ON TUE.

FOR TODAY...KEPT A CHANCE OF FLURRIES AND SNOW SHOWERS IN FOR NORTHWEST AND WEST SNOW BELTS...BUT THINGS SHOULD NOT GET OUT OF HAND AS 850 MB TEMPERATURES ARE AROUND -7C OR SO WHICH IS BORDERLINE FOR LAKE EFFECT AND INVERSIONS ARE PRETTY LOW. KEPT IN LOW CHANCE POPS FOR THIS. FOR TEMPERATURES...WENT CLOSE TO ADJMVR FOR HIGHS TODAY AND THINK THERE WILL BE CLOUDS FOR MOST OF THE DAY WITH THE BEST CHANCE FOR SEEING ANY SUNSHINE IN THE EXTREME SOUTH EARLY THIS AFTERNOON BEFORE MID CLOUDS ARRIVE BY LATE AFTERNOON WITH A SHORTWAVE MOVING THROUGH THE AREA FOR TONIGHT.

FEELING IS THAT THE SCENARIO TONIGHT AND TUESDAY MORNING WILL PLAY OUT THIS WAY. THERE WILL BE SOME MID LEVEL MOISTURE...THEN A SMALL DRY LAYER...THEN MOIST LAYER IN THE LOW LEVELS FOR A SEEDER-FEEDER MECHANISM AND WENT LOW CHANCE POPS EVERYWHERE AS THE MID LEVEL MOISTURE SPREADS ACROSS THE CWA. WENT LIKELY POPS IN THE KEWEENAW WITH SOME LAKE ENHANCEMENT THROWN IN THERE WITH 850 MB TEMPERATURES AROUND -10C WITH LAKE SUPERIOR TEMPERATURES AT AROUND 3C OR SO WHICH IS ENOUGH FOR LAKE ENHANCEMENT. WITH WEST WINDS...MADE SENSE TO GO LIKELY POPS THERE. COLDER AIR ARRIVES IN THE AFTERNOON WITH THE NAM BRINGING 850 MB TEMPERATURES DOWN TO -12C AND GFS ALSO COOLS THE TEMPERATURES AND THE WIND SWITCHES TO THE NORTH-NORTHWEST. WENT LIKELY POPS NEAR LAKE SUPERIOR IN THE AFTERNOON TO ACCOUNT FOR THIS AND THINK THERE WILL BE A SFC TROUGH GOING THROUGH THE AREA THAT COULD BRING A BRIEF BURST OF MODERATE TO HEAVY SNOW ALONG IT NEAR THE LAKE SUPERIOR SHORELINE.

FOR TUE NIGHT THROUGH THU...WENT LIKELY POPS ALONG THE LAKE SUPERIOR SHORELINE AS THE WIND BECOMES NNW TO N WHICH WILL ALLOW FOR GOOD LAKE EFFECT. PROBLEM IS THAT DRY AIR IS NOT FAR AWAY AND THERE IS SOME QUESTION AS TO WHICH WAY THE WINDS WILL BLOW. WENT CLOSE TO THE ECWMF AND GFS WHICH KEEPS THE WIND MORE NORTHERLY WHILE THE NAM AND UKMET WANTED TO GO MORE WESTERLY FOR THE WINDS. GFS HAS BEEN ADVERTISING A DECENT LAKE EFFECT EVENT FOR A WHILE AND WENT TOWARDS THAT. CONFIDENCE IN THE WINDS IS LOW THOUGH AND DID NOT FEEL CONFIDENT TO GO WITH ANY HEADLINES YET. THIS WILL CONTINUE TO HAVE TO BE WATCHED AS THERE COULD BE SOME HEADLINES THAT MIGHT BE NEEDED AT TIMES. RIGHT NOW...LOOKS LIKE WED NIGHT WOULD HAVE THE BEST CHANCE FOR HEAVY SNOW WITH STRONG NORTH WINDS. NAM BUFKIT SOUNDINGS SHOWED INVERSION HEIGHTS GETTING UP TO ABOUT 6000 FEET IN A FEW PLACES.

OVERALL...MADE A FEW CHANGES TO THE FORECAST AND BUMPED POPS UP A FEW PLACES. FOR TEMPERATURES...MADE A FEW TWEAKS HERE AND THERE AND COOLED TEMPERATURES A FEW PLACES. WENT CLOSE TO ADJMVR/ADMXR FOR TEMPERATURES.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...NONE

&&

$$

UPDATE...JLA DISCUSSION...MICHELS

.UPDATE... LOW CLOUDS AND FOG PERSISTING LONGER THAN EXPECTED THIS MORNING DUE TO STRONG INVERSION ALOFT. WITH COOLER AIR MOVING IN ALOFT AND SLOW SFC WARMING DURING THE DAY THE INVERSION SHOULD WEAKEN AND THINGS SHUD BEGIN BREAKING OUT DURING THE EARLY AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 641 AM EST MON JAN 22 2007/

AVIATION /12Z-12Z/...

SURFACE WINDS WILL BE WEST TO SOUTHWEST TODAY. THIS WILL HELP RAISE CEILINGS EAST OF THE BLUE RIDGE. CONDIITONS WILL IMPROVE IN THE EAST BY 18Z...WITH SCATTERED CLOUDS IN THE EVENINGS. IN THE WEST THE IMPROVEMENT WILL BE VERY SLOW. THE FOG IS NOT EXPECTED TO LIFT AT BLF UNTIL 15Z...THEN CEILINGS AT BLF AND LWB WILL REMAIN MVFR THROUGH THE REST OF THE FORECAST PERIOD. A COLD FRONT COMES THROUGH TONIGHT WITH STRATOCUMULUS AND SNOW SHOWERS ON THE WESTERN SLOPES OF THE APPALACHIANS. MVFR VISIBILITIES ARE EXPECTED WITH THE SNOW AT BLF AND LWB LATE TONIGHT.

PREV DISCUSSION... /ISSUED 441 AM EST MON JAN 22 2007/

SHORT TERM /TODAY THROUGH THURSDAY/...

COUNTY WARNING AREA(CWA) STAYS IN BROAD NORTHWEST FLOW AT 500 MB THROUGH THURSDAY. SHORT WAVE TROFS MOVE THROUGH THE AREA TONIGHT...ON WEDNESDAY AFTERNOON AND EVENING...AND ON THURSDAY MORNING.

MSAS LIFTED INDEX ANALYSIS AND SURFACE OBSERVATIONS SHOW THE LOCATION OF THE WEDGE FROM RIGHT ALONG THE BLUE RIDGE INTO THE EASTERN COUNTIES OF THE CWA. THE WEDGE IS FORECAST TO ERODE BETWEEN BY 18Z TODAY. SURFACE AND LOW LEVEL WINDS BECOMING WEST THIS MORNING. LITTLE OF ANY DRIZZLE LEFT NOW AND TEMPERATURES WEST OF THE BLUE RIDGE AND IN NORTH CAROLINA AND EXTREME SOUTHERN VIRGINIA ARE RISING ABOVE 32 SO ADVISORY WILL BE CANCELLED AT 5AM.

BUT...WITH WEST WIND FOG IN SOUTHEAST WEST VIRGINIA WILL BE SLOW TO DISSIPATE. MAY BE BREAKS IN THE CLOUDS EAST OF THE BLUE RIDGE THIS AFTERNOON. BUT WITHOUT MUCH SUN...WITH ICE/SLEET ON THE GROUND...AND WITH COLD AIR ADVECTION BY THE END OF THE DAY...WARMING WILL BE SLOW. WENT BELOW COLDEST GUIDANCE FOR HIGH TEMPERATURES TODAY.

FOR TONIGHT MODELS ARE SHOWING SOME FRONTOGENESIS AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY WITH THE SHORT WAVE TONIGHT. 850 MB TEMPERATURES DROP BACK WELL BELOW ZERO WITH 850 MB WINDS IN UP TO 45 KNOTS. SHORT WAVE COMBINED WITH LOW LEVEL MOISTURE AND FAVORABLE UPSLOPE WINDS WILL PRODUCE SNOW SHOWERS IN THE WESTERN CWA THROUGH TUESDAY MORNING. AIRMASS DRIES OUT ON TUESDAY WITH LITTLE CLOUDS COVER LEFT BY THE END OF THE DAY.

ON WEDNESDAY AND WEDNESDAY NIGHT THERE IS Q-VECTOR FORCING WITH THE SECOND SHORT WAVE. PLENTY OF MOISTURE MOVES BACK INTO THE AREA SO THE MOUNTAINS WILL AGAIN HAVE A CHANCE OF PRECIPITATION. AT THE SURFACE LOW PRESSURE THAT DEVELOPS IN THE OHIO RIVER VALLEY WILL MOVE INTO THE SOUTHERN APPALACHIANS BY WEDNESDAY AFTERNOON. BEHIND THIS LOW AND ASSOCIATED COLD FRONT ANOTHER SURGE OF COLD AIR MOVES INTO THE REGION.

LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...

NO CHANGES AT THIS TIME

AVIATION /10Z-06Z/...

PRECIPITATION AXIS DRIFTING TO THE SOUTHEAST THIS EVENING. THIS WILL DECREASE PRECIPITATION INTENSITIES ACROSS THE AREA. HOWEVER...THETA-E MOISTURE AXIS AND WEAK WAVE ALOFT TO KEEP DRIZZLE IN THE AREA THROUGH 10Z MONDAY. STILL SOME AREAS ALONG AND EAST OF THE BLUE RIDGE WITH TEMPERATURES AT OR BELOW FREEZING...THEREFORE ADDITIONAL GLAZING FROM FREEZING DRIZZLE IS POSSIBLE. OTHER THAN THE LIGHT PRECIPITATION...IFR CEILINGS WILL BE A HAZARD FOR AIRCRAFT THROUGH SUNRISE WITH MOUNTAIN RIDGES OBSCURED. THESE LOW CLOUDS WILL LINGER IN THE AREA UNTIL MID MORNING...THEN CONDITIONS TO SLOWLY IMPROVE TO VFR AS WEST WINDS HELP SCOUR LOW LEVEL MOISTURE IN THE AFTERNOON.

&&

.RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. &&

$$

UPDATE... SHORT TERM...JS

.AVIATION /12Z-12Z/...

SURFACE WINDS WILL BE WEST TO SOUTHWEST TODAY. THIS WILL HELP RAISE CEILINGS EAST OF THE BLUE RIDGE. CONDIITONS WILL IMPROVE IN THE EAST BY 18Z...WITH SCATTERED CLOUDS IN THE EVENINGS. IN THE WEST THE IMPROVEMENT WILL BE VERY SLOW. THE FOG IS NOT EXPECTED TO LIFT AT BLF UNTIL 15Z...THEN CEILINGS AT BLF AND LWB WILL REMAIN MVFR THROUGH THE REST OF THE FORECAST PERIOD. A COLD FRONT COMES THROUGH TONIGHT WITH STRATOCUMULUS AND SNOW SHOWERS ON THE WESTERN SLOPES OF THE APPALACHIANS. MVFR VISIBILITIES ARE EXPECTED WITH THE SNOW AT BLF AND LWB LATE TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 441 AM EST MON JAN 22 2007/

SHORT TERM /TODAY THROUGH THURSDAY/...

COUNTY WARNING AREA(CWA) STAYS IN BROAD NORTHWEST FLOW AT 500 MB THROUGH THURSDAY. SHORT WAVE TROFS MOVE THROUGH THE AREA TONIGHT...ON WEDNESDAY AFTERNOON AND EVENING...AND ON THURSDAY MORNING.

MSAS LIFTED INDEX ANALYSIS AND SURFACE OBSERVATIONS SHOW THE LOCATION OF THE WEDGE FROM RIGHT ALONG THE BLUE RIDGE INTO THE EASTERN COUNTIES OF THE CWA. THE WEDGE IS FORECAST TO ERODE BETWEEN BY 18Z TODAY. SURFACE AND LOW LEVEL WINDS BECOMING WEST THIS MORNING. LITTLE OF ANY DRIZZLE LEFT NOW AND TEMPERATURES WEST OF THE BLUE RIDGE AND IN NORTH CAROLINA AND EXTREME SOUTHERN VIRGINIA ARE RISING ABOVE 32 SO ADVISORY WILL BE CANCELLED AT 5AM.

BUT...WITH WEST WIND FOG IN SOUTHEAST WEST VIRGINIA WILL BE SLOW TO DISSIPATE. MAY BE BREAKS IN THE CLOUDS EAST OF THE BLUE RIDGE THIS AFTERNOON. BUT WITHOUT MUCH SUN...WITH ICE/SLEET ON THE GROUND...AND WITH COLD AIR ADVECTION BY THE END OF THE DAY...WARMING WILL BE SLOW. WENT BELOW COLDEST GUIDANCE FOR HIGH TEMPERATURES TODAY.

FOR TONIGHT MODELS ARE SHOWING SOME FRONTOGENESIS AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY WITH THE SHORT WAVE TONIGHT. 850 MB TEMPERATURES DROP BACK WELL BELOW ZERO WITH 850 MB WINDS IN UP TO 45 KNOTS. SHORT WAVE COMBINED WITH LOW LEVEL MOISTURE AND FAVORABLE UPSLOPE WINDS WILL PRODUCE SNOW SHOWERS IN THE WESTERN CWA THROUGH TUESDAY MORNING. AIRMASS DRIES OUT ON TUESDAY WITH LITTLE CLOUDS COVER LEFT BY THE END OF THE DAY.

ON WEDNESDAY AND WEDNESDAY NIGHT THERE IS Q-VECTOR FORCING WITH THE SECOND SHORT WAVE. PLENTY OF MOISTURE MOVES BACK INTO THE AREA SO THE MOUNTAINS WILL AGAIN HAVE A CHANCE OF PRECIPITATION. AT THE SURFACE LOW PRESSURE THAT DEVELOPS IN THE OHIO RIVER VALLEY WILL MOVE INTO THE SOUTHERN APPALACHIANS BY WEDNESDAY AFTERNOON. BEHIND THIS LOW AND ASSOCIATED COLD FRONT ANOTHER SURGE OF COLD AIR MOVES INTO THE REGION.

LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...

NO CHANGES AT THIS TIME

AVIATION /10Z-06Z/...

PRECIPITATION AXIS DRIFTING TO THE SOUTHEAST THIS EVENING. THIS WILL DECREASE PRECIPITATION INTENSITIES ACROSS THE AREA. HOWEVER...THETA-E MOISTURE AXIS AND WEAK WAVE ALOFT TO KEEP DRIZZLE IN THE AREA THROUGH 10Z MONDAY. STILL SOME AREAS ALONG AND EAST OF THE BLUE RIDGE WITH TEMPERATURES AT OR BELOW FREEZING...THEREFORE ADDITIONAL GLAZING FROM FREEZING DRIZZLE IS POSSIBLE. OTHER THAN THE LIGHT PRECIPITATION...IFR CEILINGS WILL BE A HAZARD FOR AIRCRAFT THROUGH SUNRISE WITH MOUNTAIN RIDGES OBSCURED. THESE LOW CLOUDS WILL LINGER IN THE AREA UNTIL MID MORNING...THEN CONDITIONS TO SLOWLY IMPROVE TO VFR AS WEST WINDS HELP SCOUR LOW LEVEL MOISTURE IN THE AFTERNOON.

&&

.RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. &&

$$

AVIATION...AMS

.OVERVIEW...

WINTER IS HERE AND WILL HANG AROUND FOR AWHILE.

.SHORT TERM/TONIGHT THROUGH WEDNESDAY NIGHT/...

PLENTY OF DANK AND DREARY LOOKING CLOUDS AROUND THE REGION WHICH WILL STAY AROUND FOR A COUPLE OF DAYS. NOT MUCH IN THE WAY OF WIND BUT WHEN TEMPERATURES ARE IN THE 20S, DOESN`T TAKE MUCH TO COOL YOU DOWN EVEN MORE. SO WHEN IS THE NEXT TIME FOR PRECIPITATION? THE NORTHERN BRANCH WILL PREVAIL OVER A GOOD PART OF THE WORKWEEK. SOME OF THE COLDEST TEMPERATURES WILL BE WEDNESDAY INTO THURSDAY WITH A -18C AT 80H. JUST UP THE ROAD A SHORT DISTANCE A -26C IS OVER NEW YORK STATE. THE LOW THAT BROUGHT SNOW TO US ON SUNDAY IS OFF THE COAST AND PULLING DOWN SOME COLD AIR, BUT ITS THE NEXT SHORT WAVE OVER JAMES BAY THAT IS GOING TO PUSH SOUTHEAST AND BRING THE REINFORCED COLD. ANY PRECIPITATION LIKELY TO BE IN THE FORM OF LIGHT SNOW OR A PASSING SNOW SHOWER AND THAT COULD OCCUR AT ANY TIME WITH NO ORGANIZED DYNAMICS TO SET ANYTHING OFF EXCEPT OFF THE GREAT LAKES. SO WE`LL CONTINUE TO A NORTHWEST FLOW COLD TEMPERATURES AND MOSTLY CLOUDY SKIES INTO WEDNESDAY NIGHT. MEANWHILE, CLOSED LOW OVER OLD MEXICO WILL REMAIN ANCHORED TO THE SOUTHERN IN THE TAIL END OF THE SOUTHERN BRANCH.

.LONG TERM/THURSDAY THROUGH MONDAY/...

WE CONTINUE IN THE SAME PATTERN FOR THE EXTENDED PERIOD AND IT IS EVEN COLDER THAN THE SHORT TERM. A NICE PIPE LINE OF REINFORCED COLD AIR SETS UP FROM EDMONTON DOWN THROUGH THE MID ATLANTIC COAST. ALTHOUGH COLD, THIS PATTERN WILL NOT SUPPORT THE DEVELOPMENT OF A MAJOR STORM. THE COLDEST DAY THIS WEEK LOOKS LIKE FRIDAY WITH THE NEXT SHOT OF COLD AIR. ABOUT THE THE ONLY THING WE CAN HOPE FOR IN THE WAY OF SNOW IS A CLIPPER OR TWO TO DROP ABOUT 4 TO 5 INCHES IN A FELLED SWOOP OVER OUR SOUTHERN ZONES. OUR EXTENDED PERIOD FOR 27 JAN THROUGH FEB 4 IS FOR BELOW NORMAL TEMPERATURES AND NEAR NORMAL PRECIPITATION. WHAT THIS PATTERN DOES DO IN THE LONG TERM IS SET THE STAGE, WITH THE COLD AIR IN PLACE, FOR A LOW TO DEVELOP OVER THE NORTHERN GULF AND THEN TRACK UP THROUGH THE APPALACHIANS WITH SECONDARY DEVELOPMENT OVER THE CAROLINAS. BUT THAT IS NOT IN THE FORESEEABLE FUTURE OF THE MODELS. JUST ENJOY THE SEASONABLE COLD, STAY WARM AND FOR THOSE HOPING FOR SNOW, IT WILL HAPPEN.

&& .AVIATION... THE MAJORITY OF THE TERMINALS HAVE BEEN STUCK IN THE IFR TO MVFR RANGE, HOWEVER SOME IMPROVEMENT HAS TAKEN PLACE EARLY THIS AFTERNOON AS SOMEWHAT DRIER AIR IS WORKING ITS WAY DOWN. SOME PILOT REPORTS THOUGH INDICATE MODERATE TO SEVERE ICING IN THE KABE VICINITY AT 6,000-8,000 FEET. EARLIER ACARS DATA AT PHILADELPHIA SHOWED A FAIRLY SHALLOW LAYER OF SATURATION AND THE 12Z LWX RAOB INDICATED THE MOISTURE WAS MOSTLY BELOW 5,000 FEET. VISIBLE SATELLITE IMAGERY AND SURFACE OBS SHOW A WEALTH OF CLOUDS ACROSS THE MID ATLANTIC. HOWEVER, SOME BREAKS DEVELOPED IN NORTHERN VIRGINIA. THE MAIN FORECAST CHALLENGE IS THE EXTENT OF ANY LOW-LEVEL DRYING TONIGHT INTO TUESDAY. FORECAST SOUNDINGS INDICATE NOT MUCH MIXING WITHIN THE LOWER PORTION OF THE BOUNDARY LAYER DESPITE AN INCREASING PRESSURE GRADIENT. IT APPEARS THE EXTENT OF THE MOIST LAYER HAS DECREASED THIS AFTERNOON WITH SEVERAL AREAS SEEING CEILINGS COME UP. ORGINALLY THOUGHT MOISTURE WOULD HANG TOUGH, WHICH IT HAS BUT CEILINGS ARE NOW RESPONDING IN THE UPSWING DIRECTION AT MANY LOCATIONS. NOT VERY CONFIDENT THAT THIS WILL HOLD OVERNIGHT, THEREFORE DID NOT WANT TO BE TOO OPTIMISTIC. GENERALLY HELD ONTO IFR TO MVFR CONDITIONS OVERNIGHT AS THERE IS A SHORT WAVE THAT IS FORECAST TO CRUISE ACROSS THE AREA TONIGHT, KEEPING CLOUDS IN PLACE. AREAS THAT SEE CEILINGS LIFTING SOME THIS AFTERNOON, MAY TEND TO LOWER AGAIN TONIGHT WITH THE LOW-LEVEL MOISTURE IN PLACE. THERE IS AN INCREASING PRESSURE GRADIENT OVERNIGHT, HOWEVER SURFACE WINDS MAY NOT RESPOND MUCH. WE IMPROVED THINGS THOUGH TUESDAY MORNING AS BETTER MIXING SHOULD ALLOW SOME DRYING TO TAKE PLACE. THERE COULD BE A FEW SNOW SHOWERS TONIGHT IN THE KABE AND KRDG VICINITY, WITH SOME FLURRIES POSSIBLY DOWN TO A KTTN-KILG LINE AS THE SHORT WAVE MOVES THROUGH. HOWEVER DID NOT CARRY ANY LIGHT PRECIPITATION IN THE 18Z TAFS.

&&

.MARINE... CONDITIONS RATHER TRANQUIL ACROSS THE AREA WATERS TODAY WITH SEAS 2 FEET OR LESS OVER THE COASTAL WATERS AND ABOUT A FOOT ON DELAWARE BAY. WINDS HAVE BEEN ABOUT 10 KNOTS OR LESS SO FAR. LOW PRESSURE WELL OFF THE NORTH CAROLINA COAST THIS AFTERNOON WILL CONTINUE TO MOVE NORTHEASTWARD TONIGHT WELL EAST OF OUR AREA. HOWEVER AS THIS SYSTEM MOVES TO OUR EAST THEN NORTHEAST, THE PRESSURE GRADIENT WILL TIGHTEN UP SOME OVERNIGHT AND DURING THE DAY ON TUESDAY. BUFKIT SOUNDINGS INDICATE GUSTS UP TO 25 KNOTS ARE POSSIBLE STARTING LATE TONIGHT AND CONTINUING INTO TUESDAY EVENING. FOR NOW WE WILL ALLOW FOR GUSTS TO APPROACH 25 KNOTS AND HOLD OFF ON A SMALL CRAFT ADVISORY. SOME WEAK SURFACE RIDGING MOVES IN TUESDAY EVENING, WHICH SHOULD DIMINISH THE WINDS A BIT. A STRONG COLD FRONT IS FORECAST TO APPROACH THE WATERS WEDNESDAY, THEN SWEEP ACROSS EARLY WEDNESDAY EVENING. STRONG CAA COUPLED WITH A TIGHTENING PRESSURE GRADIENT AS LOW PRESSURE DEEPENS NEAR NOVA SCOTIA WILL PRODUCE GUSTY WINDS OVER THE MARINE AREA. BUFKIT PROFILES INDICATE 30-KNOT GUSTS POSSIBLE WEDNESDAY NIGHT AND THURSDAY. AS THE CORE OF THE COLD AIR DROPS DOWN THURSDAY NIGHT AND FRIDAY, PLENTY OF WIND ALOFT COUPLED WITH COLD AIR POURING OVER THE RELATIVELY MILD WATER COULD PRODUCE GALE FORCE GUSTS. FOR THURSDAY NIGHT AND FRIDAY WAVEWATCH INDICATING 7 FOOT SEAS AT BUOY 44009. WITH THE FLOW EXPECTED TO BE OFFSHORE, WE WILL TOP THE SEAS AT ABOUT 5-6 FEET.

&&

.PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. J...NONE. DE...NONE. MD...NONE. MARINE...NONE. &&

$$

OVERVIEW/SHORT/LONG TERM...EBERWINE AVIATION/MARINE...GORSE

.SHORT TERM (TONIGHT-TUESDAY)...

EXTENSIVE LOW CLOUDS OVER THE ENTIRE OHIO VALLEY REGION TODAY. THIS COUPLED WITH WEAK COLD ADVECTION HAS LED TO STEADY OR SLOWLY FALLING TEMPS TODAY...IN THE MID-UPPER 30S MOST PLACES AS OF 19Z. SCT PRECIP ON RADAR...AND BASED ON SPOTTER REPORTS COUPLED WITH ACARS DATA... PTYPE IS A MIX OF -RA/-SN/-PL...BUT INTENSITIES ARE VERY LIGHT. EXPECT THIS TO CONTINUE FOR THE REMAINDER OF THE AFTN HOURS.

FCST SOUNDINGS SHOW LOW LEVEL LAPSE RATES STEEPENING INTO THE EVENING HOURS. THIS ALONG WITH LIFT FROM PASSING UPPER TROF WILL HELP CONTINUE POTENTIAL FOR PRECIP THIS EVENING...WILL WORD AS SLIGHT CHANCE OF -SHRA/-SHSN...HOWEVER AIRMASS ABOVE 800MB (ICE CRYSTAL LEVELS) IS FCST TO REMAIN ON THE DRY SIDE...SO PRECIP AMTS SHOULD BE LIGHT AND WE MAY END UP SEEING MORE OF A PATCHY LIGHT DRIZZLE/FLURRY TYPE DEAL. WILL MENTION ISLTD SLICK SPOTS POSSIBLE IN THE HWO FOR TONIGHT AND EARLY TUESDAY MORNING.

CHANCES FOR PRECIP SHOULD DIMINISH AFTER 6Z AS UPPER WAVE PASSES OFF TO THE EAST...BUT SKIES WILL REMAIN CLOUDY PER NAM/GFS FCST SOUNDINGS. BOTH SHOW CLOUD COVER DIMINISHING TUESDAY AS DRIER AIR ADVECTS IN FROM THE W/SW...WHICH IS OBSERVED IN VISIBLE SATELLITE OVER AR/OK ATTM. HOWEVER THAT MAY BE DELAYED DUE TO VERY STRONG INVERSION SEEN AROUND 850MB. OVERALL WILL TREND TOWARD PARTLY CLOUDY WORDING IN THE AFTN TUESDAY.

REGARDING TEMPS...USED A 50/50 BLEND OF NAM/GFS TEMPS WHICH YIELDED MIDDLE 20S MOST LOCATIONS FOR LOWS TONIGHT...AND UPPER 30S/LOWER 40S FOR HIGHS TUESDAY.

CS

.LONG TERM (TUESDAY NIGHT-MONDAY)...

TUES NIGHT-WED NIGHT...

THIS PERIOD BEGINS WITH THE UPPER FLOW PATTERN MAINLY ZONAL/SLIGHTLY NW. AT THE SFC...LOW PRESSURE AND ASSOCIATED FRONT EXTEND FROM HUDSON BAY SW TO SRN GREAT LAKES. A SHORTWAVE EMBEDDED IN WNW FLOW ALOFT IS LOCATED ACROSS THE NRN PLAINS. AT THIS TIME...THINK THE SFC FRONT FROM THE GREAT LAKES MAY STAY TO OUR NE FOR THE MOST PART...AND ONLY BRING A SLIGHT WIND SHIFT TO THE AREA WED MORNING. HOWEVER TIME-HEIGHT CROSS SECTIONS ACROSS OUR NE FROM THE NAM AND GFS INDICATE DEEPER MOISTURE FROM 06-12Z...EXTENDING INTO THE -5 TO -15 DEGREE C RANGE. THINK THAT ONLY TRACE AMOUNTS OF PRECIP WOULD OCCUR (IN THE FORM OF FLURRIES) SO MAY INSERT THIS INTO THE GRIDS. THINK A BETTER CHANCE RESIDES WITH THE UPPER PLAINS` SHORTWAVE DIVING SEWD ACROSS THE CWA WED NIGHT. THIS MAY HELP SPARK A FEW LIGHT SHOWERS ACROSS THE AREA...WITH THE BEST CHANCE ACROSS THE NERN CWA. THINK SLT CHC SNOW SHOWERS SHOULD DO THE TRICK. ANY PRECIP WOULD BE LIGHT IN NATURE.

THU-FRI...

THIS PERIOD WILL BE MAINLY DRY AS UPPER TROUGH MOVES OFF TO THE NE AND SFC HIGH PRESSURE TRIES TO NOSE IN FROM THE WEST. STILL A NW FLOW ALOFT WILL BE PRESENT ACROSS THE REGION...AND MAY HAVE SOME LINGERING FLURRIES ACROSS OUR NE THU MORN. WOULD BE A MINIMAL SHOT SO WILL NOT INSERT INTO GRIDS AT THIS TIME. MODELS HAVE BEEN TRENDING CLOSER TO THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT MODEL DOWNPLAYING THE SOUTHWARD ADVANCEMENT OF ARCTIC AIR. STILL...THINK TEMPS WILL HAVE A HARD TIME GETTING OUT OF THE 30S FOR THU UNDER THE NW FLOW (ESPECIALLY ACROSS OUR NE). TEMPS SHOULD SLOWLY MODERATE ON FRI...WITH VALUES CLOSER TO NORMAL.

SAT-MON...

THIS PERIOD POSES THE MOST UNCERTAINTY...HOWEVER FORECASTER CONFIDENCE INCREASING DUE TO THE CONSISTENCY WITH THE ECMWF. AT THE BEGINNING OF THIS PERIOD...UPPER FLOW ALOFT IS STILL A WNW FLOW...WITH A CUT-OFF LOW OVER THE SWRN CONUS FINALLY EJECTING INTO THE SRN PLAINS. MODERATING TEMPS CONTINUE WITH SWRLY SFC WINDS AND SLT RIDGING OVERHEAD. A SFC LOW IS LOCATED OVER THE GREAT LAKES REGION SAT MORN...WITH SWWD EXTENDING FRONT. THIS FRONT WILL LIKELY PASS THROUGH THE REGION SATURDAY...WHILE AT THE SAME TIME UPPER LOW EJECTING INTO PLAINS TRAVELS JUST TO OUR SOUTH. A COMBINATION OF THESE POSES A SLT PRECIP THREAT FOR THE AREA...HOWEVER QPF AMOUNTS LOOK VERY LIGHT AT THIS POINT SINCE OUR CWA RESIDES IN THE MIDDLE OF THE TWO NRN AND SRN STREAMS. WILL JUST CARRY SLT CHC POPS...AND WOULD LIKELY START OFF AS LIQUID. SAT NIGHT...PRECIP SHOULD SWITCH TO -SHSN AS TEMPS AT 850MB DROP TO AROUND -12 DEGREES C. UPPER TROUGH BEHIND NRN STREAM FRONT TRIES TO BRING ARCTIC AIR INTO THE REGION...HOWEVER TREND IS TO LIGHTEN THE PUNCH...WITH THE NE CONUS REALLY EXPERIENCING THE WORST OF THE ARCTIC AIR. COULD HAVE A CHC OF FLURRIES WITH THE UPPER TROUGH PASSAGE...BUT GIVEN VERY DRY ATMS WILL NOT INSERT INTO THE GRIDS FOR SUNDAY AT THIS TIME. DESPITE THE MODELS TRENDING TOWARD KEEPING THE COLDEST TEMPS TO OUR NE...ENSEMBLES STILL SHOW TEMPS 1 STD DEV BELOW NORM SUN-MON...SO WILL TREND TOWARD ROUGHLY 3-5 DEGREES BELOW NORMAL FOR THESE DAYS.

AL

&&

.AVIATION (18Z TAFS)...

EXTENSIVE LOW STRATUS WILL BE THE DOMINANT FORECAST PROBLEM FOR AVIATION CONCERNS THE NEXT 24 HRS.

BASED ON OBSERVATIONAL TRENDS AND LATEST RUC/NAM SOUNDINGS... EXPECT SCT AREAS OF DRIZZLE/-SHRA TO CONTINUE THROUGH THE AFTN HOURS. THESE WILL LOCALLY REDUCE CIGS/VSBYS TO AROUND 700FT/1SM RESPECTIVELY. OTHERWISE CIGS WILL REMAIN IN THE MVFR CATEGORY THROUGH 0Z...WITH VSBYS IN THE VFR RANGE. WILL MAINTAIN 6SM -DZ BR AS PREVAILING AT SDF/LEX/BWG.

INTO THIS EVENING LOWER LEVELS COOL SUCH THAT A FEW FLURRIES OR -SHSN MAY BE POSSIBLE HOWEVER COVERAGE IS NOT ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. LOW LEVEL RH FIELDS SUGGEST THAT CIGS MAY LIFT SLIGHTLY FROM LATE AFTN INTO THE EVENING AS DRIER AIR SLIDES ACROSS THE CWA...BUT ONLY TEMPORARILY. NAM FCST SOUNDINGS THEN INDICATE THAT CIGS MAY BECOME QUITE LOW (LIFR) AFTER 6Z (ESPECIALLY AT LEX) WHILE MOS GUIDANCE IS LESS PESSIMISTIC. WILL GO WITH A BLEND OF SOLUTIONS FOR THE TIME BEING.

WITH HIGH PRES MOVING INTO THE REGION FROM THE PLAINS...WINDS WILL GENERALLY BE WESTERLY AND LIGHT...AOB 10KTS THROUGH THE 18Z TAF PERIOD.

CS

&&

.LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE.

&&

$$

.AVIATION (18Z TAFS)... EXTENSIVE LOW STRATUS WILL BE THE DOMINANT FORECAST PROBLEM FOR AVIATION CONCERNS THE NEXT 24 HRS.

BASED ON OBSERVATIONAL TRENDS AND LATEST RUC/NAM SOUNDINGS... EXPECT SCT AREAS OF DRIZZLE/-SHRA TO CONTINUE THROUGH THE AFTN HOURS. THESE WILL LOCALLY REDUCE CIGS/VSBYS TO AROUND 700FT/1SM RESPECTIVELY. OTHERWISE CIGS WILL REMAIN IN THE MVFR CATEGORY THROUGH 0Z...WITH VSBYS IN THE VFR RANGE. WILL MAINTAIN 6SM -DZ BR AS PREVAILING AT SDF/LEX/BWG.

INTO THIS EVENING LOWER LEVELS COOL SUCH THAT A FEW FLURRIES OR -SHSN MAY BE POSSIBLE HOWEVER COVERAGE IS NOT ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. LOW LEVEL RH FIELDS SUGGEST THAT CIGS MAY LIFT SLIGHTLY FROM LATE AFTN INTO THE EVENING AS DRIER AIR SLIDES ACROSS THE CWA...BUT ONLY TEMPORARILY. NAM FCST SOUNDINGS THEN INDICATE THAT CIGS MAY BECOME QUITE LOW (LIFR) AFTER 6Z (ESPECIALLY AT LEX) WHILE MOS GUIDANCE IS LESS PESSIMISTIC. WILL GO WITH A BLEND OF SOLUTIONS FOR THE TIME BEING.

WITH HIGH PRES MOVING INTO THE REGION FROM THE PLAINS...WINDS WILL GENERALLY BE WESTERLY AND LIGHT...AOB 10KTS THROUGH THE 18Z TAF PERIOD.

CS

&&

.PREV DISCUSSION... /ISSUED 1036 AM EST MON JAN 22 2007/

UPDATE... AREAS OF DRIZZLE OR -SHRA ARE CONTINUING OVER THE LMK CWA THIS MORNING BASED ON LOCAL RADARS. ACARS SOUNDINGS AND LATEST RUC INDICATE THAT PTYPE SHOULD REMAIN LIQUID TODAY...WITH ATMOS ABOVE 800MB/-7C REMAINING DRY. WILL INCLUDE AREAS OF DRIZZLE WITH A SLIGHT CHANCE OF RAIN SHOWERS GIVEN COVERAGE OF PRECIP ON RADAR CURRENTLY AND VSBYS NEAR 1SM AT FTK. IT`S CONCEIVABLE THAT WITHIN SPOTS OF HIGHER REFLECTIVITY/DEEPER SATURATION...THERE COULD BE A BRIEF RA/SN SHOWER...SOMETHING TO WATCH TODAY.

INCOMING 12Z NAM IS SHOWING STEEP LOW LEVEL LAPSE RATES CONTINUING INTO THE EVENING HOURS...SO HAVE EXTENDED DRIZZLE/SHRA INTO THE EVENING ACROSS THE CWA. MAY SEE A TRANSITION TO FLURRIES AS LOW LEVELS COOL. TEMPS TODAY WILL BE A CHALLENGE. EXTENSIVE CLOUD COVER AND WEAK COLD ADVECTION SHOULD KEEP READINGS NEARLY STEADY.

UPDATED FCST WILL BE OUT BY 11 AM EST.

CS

PREV DISCUSSION... /ISSUED 844 AM EST MON JAN 22 2007/

UPDATE... QUICK UPDATE TO ACCOUNT FOR PRECIP DEVELOPING FROM NEAR SDF/FTK OVER INTO SRN INDIANA AND SOUTH TO NEAR BWG. WILL REFER TO THIS AS PATCHY DRIZZLE. PTYPE BASED ON LATEST ACARS/RUC SOUNDINGS SHOULD REMAIN LIQUID (DRIZZLE) AS CRITICAL ICE CRYSTAL LAYER IS DRY. REST OF FCST UNCHANGED AT THIS TIME.

CS

&&

PREV DISCUSSION... /ISSUED 316 AM EST MON JAN 22 2007/

SHORT TERM (TODAY AND TONIGHT)...

SHORT TERM MODELS SHOW VERY LITTLE DISAGREEMENT THRU THE NEXT 24 HRS...WILL LEAN TOWARDS A BLEND OF THE 21Z SREF AND THE 00Z GFS FOR THE FORECAST PERIOD. ONLY SIGNIFICANT FORECAST PROBLEM IS DEALING WITH TEMPS AND CLOUDS.

MODEST POSITIVE TILT TROUGH ACROSS THE WESTERN GREAT LAKES INTO THE PLAINS...WITH CLOSED LOW ACROSS THE GADSDEN PURCHASE REGION OF THE DESERT SOUTHWEST AND WEAK SE CONUS RIDGING. SFC HI PRESSURE SITS JUST TO THE WEST OF THE REGION...PRODUCING WNW WINDS. TROUGH SHIFTS EAST FROM THE PLAINS INTO THE MS VALLEY BY AFTERNOON...BRINGING IN SLIGHTLY COLDER AIR ALOFT AT 850 MB...850 TEMPS DROPPING TO AROUND -8C. TROUGH PUSHES ON THROUGH THE MID OHIO VALLEY DURING THE OVERNIGHT PERIOD...AS SFC RIDGING NUDGES EAST IN THE REGION WITH SLIGHT 850 MB WARMING TOWARDS -4C AS THE TROUGH PUSHES EAST BY 12Z TUES.

TIME SERIES OF BWG/LEX/SDF EACH SHOW SIGNIFICANT INVERSION TRAPPING MOISTURE BELOW 850 MB...WITH SFC TO 850 MB RH AVG AROUND 90-95 PERCENT THROUGH 12Z TUES. ABOVE THE 850 MB LAYER THE ATMS IS MUCH DRIER AND WARMER WITH RH AROUND 15-20 PERCENT THROUGHOUT MUCH OF THE COLUMN...AND TEMPS WARMING IN THE WSW FLOW AROUND 750 TO 700 MB TO 0C. BEFORE COOLING AS THE FLOW WEAKENS OVERNIGHT. SO WILL KEEP THE CLOUDY SKIES THROUGH THE ENTIRE PERIOD...WEAK LIFT SEEN JUST ABOVE THE MOISTURE DURING THE AFTERNOON AND WILL HAVE DRIZZLE IN AROUND NOON THRU 5PM.

THE NGMMOS HAS BEEN VERY INCONSISTENT AND JUMPY THE LAST 3 RUNS SO WILL DISCOUNT...WILL LEAN TOWARDS A BLEND OF THE MET/MAV MOS THIS AFTERNOON. EACH OF THE TWO HAS SHOWED A TREND OF ABOUT 1 DEGREE COOLER FOR THE AFTERNOON HIGHS...EASILY EXPLAINABLE DUE TO THE CLOUDS CREATING LESS HEATING. WILL GO A DEGREE OR TWO WARMER FOR OVERNIGHT LOWS THAN USING A STRAIGHT BLEND OF THE TWO ALSO DUE TO THE CLOUDS.

SCHOTT

LONG-TERM (TUESDAY THROUGH SUNDAY)...

THE LONG TERM PERIOD IS STILL CHARACTERIZED BY THE PERSISTENT MEAN RIDGE ALONG OR A LITTLE WEST OF THE WEST COAST OF THE US AND WESTERN CANADA. EARLY IN THE PERIOD ANOTHER CUTOFF LOW DEVELOPS OVER THE SOUTHWESTERN U.S. INTO NORTHWEST MEXICO THAT COULD IMPACT OUR REGION OVER THE WEEKEND. AT THE SAME TIME...A STRONG SHORT WAVE MOVING INTO NORTHWEST CANADA TO THE SOUTHEAST OF AK...BRIEFLY FLATTENS THE WESTERN CANADA RIDGE AND THEN DIGS SOUTHEAST INTO THE SOUTHERN HUDSON BAY REGION AND IS FOLLOWED BY A SERIES OF OTHER SHORT WAVES THAT PROMISE TO KEEP THIS NORTHERN STREAM AS THE CONTROLLING WEATHER MAKER FOR OUR REGION BEFORE BREAKING DOWN A BIT OVER NEXT WEEKEND.

DURING THE WEDNESDAY-THURSDAY TIME FRAME THIS FIRST CLIPPER LIKE SYSTEM BRINGS ANOTHER SURGE OF ARCTIC AIR SOUTHWARD INTO THE REGION. THIS COULD LEAD TO A PERIOD OF SNOW SHOWERS AND/OR FLURRIES FOR A TIME DURING THE ABOVE MENTIONED COUPLE OF DAYS. THIS IS MORE OR LESS IN LINE WITH OUR CURRENT FCST.

OVER THE WEEKEND THE NORTHERN STREAM IS MERGED BY THE REMNANTS OF THE SOUTHWESTERN CUTOFF AND LEADS TO ANOTHER CHC FOR SOME RAIN OR SNOW. THIS COULD BE ANOTHER SIMILAR SCENARIO TO THIS PAST WEEKEND. BOTH THE ECMWF AND GFS SHOW A SIMILAR TREND BUT WITH SOME SIGNIFICANT TIMING DIFFERENCES...THIS WILL HAVE TO BE WATCHED CLOSELY.

ONLY REAL CHANGES TO THE CURRENT FCSTS WERE SOME MINOR TWEAKS WITH THE HOURLY AND MAX AND MIN TEMPS FOR BETTER CONSISTENCY WITH THE SURROUNDING FA`S. --21

&&

.LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. &&

$$

.DISCUSSION... 12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NRN BRANCH NW FLOW ALF OVER THE UPR GRT LKS BTWN RDG OVER THE NRN ROCKIES/SW CAN AND GENERAL TROFFING IN SE CAN. DEEPER MSTR CONFINED TO THE SRN CONUS WITHIN THE SRN BRANCH FLOW THERE. FA CURRENTLY UNDER THE INFLUENCE OF WEAK SFC-H7 RDG NOSING INTO THE UPR GRT LKS. ALTHOUGH THERE HAVE BEEN SOME FLURRIES/-SN ARND IN ASSOCIATION WITH DEPARTING WEAK TROF NOW OVER ERN LK SUP AS WELL AS SOME SFC-H8 MSTR SHOWN ON THE 12Z APX/GRB RAOBS AND 16Z TAMDAR SDNG FM SAW...WHAT LTL SN THAT IS FALLING APPEARS TO BE DIMINISHING/ENDING W-E AS DRIER AIR SHOWN ON THE 12Z INL SDNG PUSHES INTO THE UPR GRT LKS. 12Z PWAT AT INL ONLY 0.16 INCH. NEXT SHRTWV OF CONCERN NOW MOVING INTO CNTRL MANITOBA. PCPN IN ADVANCE OF THIS FEATURE IS QUITE LIMITED BY DRY AIR SHOWN ON THE 12Z INL/BIS/YQD SDNGS DESPITE MODEST ISENTROPIC LIFT/PRES FALLS IN THE SW FLOW AHEAD OF SHRTWV.

MAIN FCST CONCERNS THE NEXT FEW DAYS REVOLVE ARND TIMING/IMPACT OF UPSTREAM SHRTWV DROPPING INTO THE UPR GRT LKS IN NW FLOW ALF.

FOR TNGT...GOOD AGREEMENT AMONG NAM/GFS/CNDN MODELS SHOWING SHRTWV NOW OVER MANITOBA REACHING CNTRL UPR MI BY 12Z TUE. GFS SHOWS AREA OF H85-5 QVECTOR CNVGC/DPVA MOVING INTO THE FA OVERNGT WHILE ISENTROPIC LIFT APPEARS TO WEAKEN. CONSIDERING DRY AIR UPSTREAM AND MINIMAL MOS POPS...PREFER THE DRIER LOOK OF THE NAM FCST SDNGS. HAVE OPTED TO CARRY CHC POPS ONLY ACRS THE NRN TIER ON CYC SIDE OF H5 VORT TRACK WITH JUST FLURRIES ALG THE WI BORDER/SCNTRL. HIEST POP TO LIKELY OVER THE KEWEENAW...BUT AOB 50 ELSEWHERE. GIVEN OBSVD LO MIN TEMPS UPSTREAM THIS MRNG AND RELATIVELY DRY AIR...WL TEND TOWARD THE LOWER ETA/NGM MOS GUIDANCE FOR MIN TEMPS.

EXPECT LES TO DVLP ON TUE DOWNWIND OF LK SUP IN FCST NNW FLOW BEHIND SHRTWV AS H85 TEMPS AS LO AS -15C TO -17C ADVECT INTO THE NRN TIER ZNS BY 00Z WED. WL CARRY LIKELY POPS NR LK SUP AND JUST A CHC OF -SHSN/FLURRIES FARTHER INLAND. INCOMING AIRMASS APPEARS TO BE RATHER DRY WITH INVRN LWRG TO ARND H85 DURING THE AFTN UNDER H85-5 QVECTOR DVGC/DNVA/SUBSIDENCE...SO EXPECT SUB ADVY ACCUMULATIONS. EXPECT HI TEMPS RELATIVELY EARLY IN THE DAY BEFORE INFUSION OF COLDER AIR CAUSES TEMPS REMAIN NEARLY STEADY IN THE AFTN. LES MODERATED BY LOW INVRN HGT/DRY AIR/LARGER SCALE ACYC FLOW/LWRG INVRN HGT WL CONTINUE NR LK SUP TUE NGT. OVER THE INTERIOR...EXPECT TEMPS TO FALL BLO MOS GUIDANCE AWAY FM LK MODERATION WITH DIMINISHING WINDS/APRCH OF RDG AXIS/PWAT ARND 0.1 INCH.

NEXT CLIPPER SHRTWV PROGGED TO DIG INTO THE UPR LKS ON WED...WITH FAIRLY VIGOROUS DPVA/H85-5 QVECTOR CNVGC CONTIBUTING TO 12Z-24Z H5 HGT FALLS UP TO 60M. BUT DEEPER MSTR FCST TO REMAIN LOCKED UP WITH SRN BRANCH AND QUITE LIMITED THIS FAR N (GFS FCST PWAT AOB 0.2 INCH). SO THINK ANY SYNOPTIC SN WL BE UNDER AN INCH...WITH THE HIER POPS CLOSE TO LK SUP WHERE OPPORTUNITY FOR ADDITIONAL LK MOISTENING WL BE THERE. ARRIVAL OF H85 TEMPS AOB -20C IN THE WAKE OF THIS SYS WL CRANK UP LES MACHINE WED AFTN/WED NGT...BUT TEMPS MAY BE TOO LO FOR OPTIMUM SN GROWTH/SGFNT ACCUMULATIONS DESPITE RELATIVELY HI POPS IN FVRD AREAS NR LK SUP FOR NNW FLOW.

CYC NNE FLOW IN WAKE OF CLIPPER SHRTWV WL BEGIN TO WEAKEN ON THU UNDER SLOWLY BLDG UPR HGTS/APRCHG ARCTIC HI PRES CENTER. 12Z GFS HAS TRENDED MUCH FASTER THAN PREVIOUS RUNS/OTHER OPS MODELS/00Z GFS REFCST ENSEMBLE MEAN...SO REJECTED ITS SOLN FOR TIMING OF SHRTWV AFT THU. WL MAINTAIN LIKELY POPS NR LK SUP THRU THE DAY PER 12Z ECMWF... THEN DIMINISH POPS THU NGT WITH APRCH OF SFC RDG AXIS. EXPECT A VERY COLD NGT WITH TEMPS BLO MOS GUIDANCE OVER THE WCNTRL INTERIOR WITH LGT WINDS/PCLDY SKIES. UPR RDGING WL DOMINATE ON FRI...AND ANY LINGERING SHSN WL END EARLY OVER THE E AS LLVL FLOW FCST TO TURN TO THE SW AHEAD OF NEXT SHRTWV DROPPING THRU SCNTRL CAN. THIS SYS FCST TO IMPACT THE FA EARLY THIS COMING WEEKEND WITH ONE OF COLDEST AIRMASSES OF THE SEASON FOLLOWING LATER IN THE WEEKEND (ECMWF FCST H85 TEMPS TO -22C...GFS FCST TO -26C). ALTHOUGH THE AIRMASS APPEARS TO BE TOO DRY TO SUPPORT POPS AHEAD OF THE INITIAL COLD FROPA FRI NGT...EXPECT INCRSG POPS ON SAT WITH ARRIVAL OF UPR TROF/FALLING HGTS. LES WL BE AN ISSUE ON SAT NGT INTO SUN NGT AS THE COLDER AIR POURS ACRS LK SUP WITH BLUSTERY NNW WIND. THEN EXPECT A MORE TRANQUIL DAY ON MON WITH SFC RDG MOVING ACRS THE AREA AS HGTS RECOVER IN ADVANCE OF ANOTHER CLIPPER SHRTWV. BUT TIMING OF THIS SYS AS WELL AS POTENTIAL FOR LINGERING LES WARRANT LO CHC POPS THE ENTIRE DAY.

COORDINATED WITH APX/GRB/DLH.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...NONE

&&

$$ KC

.AVIATION /18Z-18Z/... LOWS CLOUDS AND FOG IN THE EAST WILL LIKELY PERSIST THRU MID AFTN. ALTHOUGH FINALLY STARTING TO SEE SOME HIGHER CIGS AND VSBYS AT LYH. VERY DIFFICULT TO KNOW WHEN THINGS WILL BREAK...BUT WILL CONTINUE TO FCST A GRADUAL IMPROVEMENT OVER THE NEXT SEVERAL HOURS AT LYH AND DAN. THINGS WILL REMAIN PRETTY MUCH STATUS QUO AT BLF/LWB/ROA THRU THE AFTN. SNOW SHOWERS INCREASE THIS EVENING IN THE WEST. EXPECT VFR IN THE EAST TNGT AS WEST WINDS BEGIN TO MIX. HOWEVER WILL HAVE TO WATCH DAN/LYH AS MIXING MAY NOT PAN OUT AND THEY COULD FALL INTO A RADIATIONAL FOG SITUATION.

&&

.PREV DISCUSSION... /ISSUED 1241 PM EST MON JAN 22 2007/

UPDATE... JUST ABOUT GIVEN UP ON SEEING SUN THE REST OF THE DAY AS IN SITU DAMMING AND RESULTANT INVERSION ALOFT STILL TOO STRONG FOR LATE JANUARY SUN TO BREAK...ESP WITH HIGH CLOUDS STILL STREAMING OVERHEAD. HAVE LOWERED TEMPS IN THE CENTRAL PIEDMONT WHERE TEMPS STILL NEAR FREEZING.

PREV DISCUSSION... /ISSUED 1005 AM EST MON JAN 22 2007/

UPDATE... LOW CLOUDS AND FOG PERSISTING LONGER THAN EXPECTED THIS MORNING DUE TO STRONG INVERSION ALOFT. WITH COOLER AIR MOVING IN ALOFT AND SLOW SFC WARMING DURING THE DAY THE INVERSION SHOULD WEAKEN AND THINGS SHUD BEGIN BREAKING OUT DURING THE EARLY AFTERNOON.

PREV DISCUSSION... /ISSUED 641 AM EST MON JAN 22 2007/

AVIATION /12Z-12Z/...

SURFACE WINDS WILL BE WEST TO SOUTHWEST TODAY. THIS WILL HELP RAISE CEILINGS EAST OF THE BLUE RIDGE. CONDIITONS WILL IMPROVE IN THE EAST BY 18Z...WITH SCATTERED CLOUDS IN THE EVENINGS. IN THE WEST THE IMPROVEMENT WILL BE VERY SLOW. THE FOG IS NOT EXPECTED TO LIFT AT BLF UNTIL 15Z...THEN CEILINGS AT BLF AND LWB WILL REMAIN MVFR THROUGH THE REST OF THE FORECAST PERIOD. A COLD FRONT COMES THROUGH TONIGHT WITH STRATOCUMULUS AND SNOW SHOWERS ON THE WESTERN SLOPES OF THE APPALACHIANS. MVFR VISIBILITIES ARE EXPECTED WITH THE SNOW AT BLF AND LWB LATE TONIGHT.

PREV DISCUSSION... /ISSUED 441 AM EST MON JAN 22 2007/

SHORT TERM /TODAY THROUGH THURSDAY/...

COUNTY WARNING AREA(CWA) STAYS IN BROAD NORTHWEST FLOW AT 500 MB THROUGH THURSDAY. SHORT WAVE TROFS MOVE THROUGH THE AREA TONIGHT...ON WEDNESDAY AFTERNOON AND EVENING...AND ON THURSDAY MORNING.

MSAS LIFTED INDEX ANALYSIS AND SURFACE OBSERVATIONS SHOW THE LOCATION OF THE WEDGE FROM RIGHT ALONG THE BLUE RIDGE INTO THE EASTERN COUNTIES OF THE CWA. THE WEDGE IS FORECAST TO ERODE BETWEEN BY 18Z TODAY. SURFACE AND LOW LEVEL WINDS BECOMING WEST THIS MORNING. LITTLE OF ANY DRIZZLE LEFT NOW AND TEMPERATURES WEST OF THE BLUE RIDGE AND IN NORTH CAROLINA AND EXTREME SOUTHERN VIRGINIA ARE RISING ABOVE 32 SO ADVISORY WILL BE CANCELLED AT 5AM.

BUT...WITH WEST WIND FOG IN SOUTHEAST WEST VIRGINIA WILL BE SLOW TO DISSIPATE. MAY BE BREAKS IN THE CLOUDS EAST OF THE BLUE RIDGE THIS AFTERNOON. BUT WITHOUT MUCH SUN...WITH ICE/SLEET ON THE GROUND...AND WITH COLD AIR ADVECTION BY THE END OF THE DAY...WARMING WILL BE SLOW. WENT BELOW COLDEST GUIDANCE FOR HIGH TEMPERATURES TODAY.

FOR TONIGHT MODELS ARE SHOWING SOME FRONTOGENESIS AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY WITH THE SHORT WAVE TONIGHT. 850 MB TEMPERATURES DROP BACK WELL BELOW ZERO WITH 850 MB WINDS IN UP TO 45 KNOTS. SHORT WAVE COMBINED WITH LOW LEVEL MOISTURE AND FAVORABLE UPSLOPE WINDS WILL PRODUCE SNOW SHOWERS IN THE WESTERN CWA THROUGH TUESDAY MORNING. AIRMASS DRIES OUT ON TUESDAY WITH LITTLE CLOUDS COVER LEFT BY THE END OF THE DAY.

ON WEDNESDAY AND WEDNESDAY NIGHT THERE IS Q-VECTOR FORCING WITH THE SECOND SHORT WAVE. PLENTY OF MOISTURE MOVES BACK INTO THE AREA SO THE MOUNTAINS WILL AGAIN HAVE A CHANCE OF PRECIPITATION. AT THE SURFACE LOW PRESSURE THAT DEVELOPS IN THE OHIO RIVER VALLEY WILL MOVE INTO THE SOUTHERN APPALACHIANS BY WEDNESDAY AFTERNOON. BEHIND THIS LOW AND ASSOCIATED COLD FRONT ANOTHER SURGE OF COLD AIR MOVES INTO THE REGION.

LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...

NO CHANGES AT THIS TIME

AVIATION /10Z-06Z/...

PRECIPITATION AXIS DRIFTING TO THE SOUTHEAST THIS EVENING. THIS WILL DECREASE PRECIPITATION INTENSITIES ACROSS THE AREA. HOWEVER...THETA-E MOISTURE AXIS AND WEAK WAVE ALOFT TO KEEP DRIZZLE IN THE AREA THROUGH 10Z MONDAY. STILL SOME AREAS ALONG AND EAST OF THE BLUE RIDGE WITH TEMPERATURES AT OR BELOW FREEZING...THEREFORE ADDITIONAL GLAZING FROM FREEZING DRIZZLE IS POSSIBLE. OTHER THAN THE LIGHT PRECIPITATION...IFR CEILINGS WILL BE A HAZARD FOR AIRCRAFT THROUGH SUNRISE WITH MOUNTAIN RIDGES OBSCURED. THESE LOW CLOUDS WILL LINGER IN THE AREA UNTIL MID MORNING...THEN CONDITIONS TO SLOWLY IMPROVE TO VFR AS WEST WINDS HELP SCOUR LOW LEVEL MOISTURE IN THE AFTERNOON.

&&

.RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. &&

$$

AVIATION...JS

.UPDATE... JUST ABOUT GIVEN UP ON SEEING SUN THE REST OF THE DAY AS IN SITU DAMMING AND RESULTANT INVERSION ALOFT STILL TOO STRONG FOR LATE JANUARY SUN TO BREAK...ESP WITH HIGH CLOUDS STILL STREAMING OVERHEAD. HAVE LOWERED TEMPS IN THE CENTRAL PIEDMONT WHERE TEMPS STILL NEAR FREEZING.

&&

.PREV DISCUSSION... /ISSUED 1005 AM EST MON JAN 22 2007/

UPDATE... LOW CLOUDS AND FOG PERSISTING LONGER THAN EXPECTED THIS MORNING DUE TO STRONG INVERSION ALOFT. WITH COOLER AIR MOVING IN ALOFT AND SLOW SFC WARMING DURING THE DAY THE INVERSION SHOULD WEAKEN AND THINGS SHUD BEGIN BREAKING OUT DURING THE EARLY AFTERNOON.

PREV DISCUSSION... /ISSUED 641 AM EST MON JAN 22 2007/

AVIATION /12Z-12Z/...

SURFACE WINDS WILL BE WEST TO SOUTHWEST TODAY. THIS WILL HELP RAISE CEILINGS EAST OF THE BLUE RIDGE. CONDIITONS WILL IMPROVE IN THE EAST BY 18Z...WITH SCATTERED CLOUDS IN THE EVENINGS. IN THE WEST THE IMPROVEMENT WILL BE VERY SLOW. THE FOG IS NOT EXPECTED TO LIFT AT BLF UNTIL 15Z...THEN CEILINGS AT BLF AND LWB WILL REMAIN MVFR THROUGH THE REST OF THE FORECAST PERIOD. A COLD FRONT COMES THROUGH TONIGHT WITH STRATOCUMULUS AND SNOW SHOWERS ON THE WESTERN SLOPES OF THE APPALACHIANS. MVFR VISIBILITIES ARE EXPECTED WITH THE SNOW AT BLF AND LWB LATE TONIGHT.

PREV DISCUSSION... /ISSUED 441 AM EST MON JAN 22 2007/

SHORT TERM /TODAY THROUGH THURSDAY/...

COUNTY WARNING AREA(CWA) STAYS IN BROAD NORTHWEST FLOW AT 500 MB THROUGH THURSDAY. SHORT WAVE TROFS MOVE THROUGH THE AREA TONIGHT...ON WEDNESDAY AFTERNOON AND EVENING...AND ON THURSDAY MORNING.

MSAS LIFTED INDEX ANALYSIS AND SURFACE OBSERVATIONS SHOW THE LOCATION OF THE WEDGE FROM RIGHT ALONG THE BLUE RIDGE INTO THE EASTERN COUNTIES OF THE CWA. THE WEDGE IS FORECAST TO ERODE BETWEEN BY 18Z TODAY. SURFACE AND LOW LEVEL WINDS BECOMING WEST THIS MORNING. LITTLE OF ANY DRIZZLE LEFT NOW AND TEMPERATURES WEST OF THE BLUE RIDGE AND IN NORTH CAROLINA AND EXTREME SOUTHERN VIRGINIA ARE RISING ABOVE 32 SO ADVISORY WILL BE CANCELLED AT 5AM.

BUT...WITH WEST WIND FOG IN SOUTHEAST WEST VIRGINIA WILL BE SLOW TO DISSIPATE. MAY BE BREAKS IN THE CLOUDS EAST OF THE BLUE RIDGE THIS AFTERNOON. BUT WITHOUT MUCH SUN...WITH ICE/SLEET ON THE GROUND...AND WITH COLD AIR ADVECTION BY THE END OF THE DAY...WARMING WILL BE SLOW. WENT BELOW COLDEST GUIDANCE FOR HIGH TEMPERATURES TODAY.

FOR TONIGHT MODELS ARE SHOWING SOME FRONTOGENESIS AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY WITH THE SHORT WAVE TONIGHT. 850 MB TEMPERATURES DROP BACK WELL BELOW ZERO WITH 850 MB WINDS IN UP TO 45 KNOTS. SHORT WAVE COMBINED WITH LOW LEVEL MOISTURE AND FAVORABLE UPSLOPE WINDS WILL PRODUCE SNOW SHOWERS IN THE WESTERN CWA THROUGH TUESDAY MORNING. AIRMASS DRIES OUT ON TUESDAY WITH LITTLE CLOUDS COVER LEFT BY THE END OF THE DAY.

ON WEDNESDAY AND WEDNESDAY NIGHT THERE IS Q-VECTOR FORCING WITH THE SECOND SHORT WAVE. PLENTY OF MOISTURE MOVES BACK INTO THE AREA SO THE MOUNTAINS WILL AGAIN HAVE A CHANCE OF PRECIPITATION. AT THE SURFACE LOW PRESSURE THAT DEVELOPS IN THE OHIO RIVER VALLEY WILL MOVE INTO THE SOUTHERN APPALACHIANS BY WEDNESDAY AFTERNOON. BEHIND THIS LOW AND ASSOCIATED COLD FRONT ANOTHER SURGE OF COLD AIR MOVES INTO THE REGION.

LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...

NO CHANGES AT THIS TIME

AVIATION /10Z-06Z/...

PRECIPITATION AXIS DRIFTING TO THE SOUTHEAST THIS EVENING. THIS WILL DECREASE PRECIPITATION INTENSITIES ACROSS THE AREA. HOWEVER...THETA-E MOISTURE AXIS AND WEAK WAVE ALOFT TO KEEP DRIZZLE IN THE AREA THROUGH 10Z MONDAY. STILL SOME AREAS ALONG AND EAST OF THE BLUE RIDGE WITH TEMPERATURES AT OR BELOW FREEZING...THEREFORE ADDITIONAL GLAZING FROM FREEZING DRIZZLE IS POSSIBLE. OTHER THAN THE LIGHT PRECIPITATION...IFR CEILINGS WILL BE A HAZARD FOR AIRCRAFT THROUGH SUNRISE WITH MOUNTAIN RIDGES OBSCURED. THESE LOW CLOUDS WILL LINGER IN THE AREA UNTIL MID MORNING...THEN CONDITIONS TO SLOWLY IMPROVE TO VFR AS WEST WINDS HELP SCOUR LOW LEVEL MOISTURE IN THE AFTERNOON.

&&

.RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. &&

$$

UPDATE...