Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 03/16/07

AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1300 AM EDT WED MAR 14 2007 .MORNING UPDATE... INITIAL SHORTWAVE THAT BROUGHT RAIN EARLIER THIS MORNING ACROSS KENTUCKY HAS MOVED INTO OHIO. IN ITS WAKE...WEAK SUBSIDENCE HAS PRODUCED PARTLY CLOUDY SKIES AND MILD TEMPERATURES. LOCAL SOUNDINGS AND SATELLITE IMAGERY SHOW THAT ALTHOUGH SOME INSTABILITY WILL DEVELOP THIS AFTERNOON...A LACK OF ANY UPPER LEVEL SUPPORT MAY DELAY ANY THUNDERSTORM DEVELOPMENT UNTIL LATE THIS AFTERNOON OR EVENING. HAVE DELAYED LIKELY THUNDERSTORM DEVELOPMENT UNTIL THIS EVENING...AND TRENDED SKIES TOWARDS PARTLY CLOUDY. JSD .SHORT TERM (TODAY AND TONIGHT)... UPPER VORT PRODUCING SCATTERED SHOWERS ACROSS THE LOUISVILLE FORECAST AREA AT 06Z WILL CONTINUE ITS MARCH TO THE NORTHEAST AND WILL TAKE ITS SHOWERS OUT OF OUR AREA EARLY THIS MORNING. WE SHOULD THEN HAVE SEVERAL MOSTLY DRY HOURS FROM MID MORNING INTO EARLY AFTERNOON. UPPER LOW OVER TEXAS WILL CONTINUE TO EDGE SLOWLY EAST...CROSSING TEXAS TODAY AND ENTERING THE LOWER MISSISSIPPI VALLEY TONIGHT. IT WILL SEND ANOTHER SMALL VORT MAX NORTHEAST TODAY...CROSSING CENTRAL KENTUCKY LATE THIS AFTERNOON AND THIS EVENING. THIS FEATURE WILL HELP TO SPARK OFF SHOWERS AND THUNDERSTORMS. IN ADDITION...TONIGHT AN EAST-WEST COLD FRONT WILL DROP SOUTH OUT OF THE MIDWEST AND GREAT LAKES INTO THE OHIO VALLEY. TIMING DIFFERENCES NOTED BY THE DAY SHIFT YESTERDAY CONTINUE...WITH THE NAM12 ABOUT 8 HOURS SLOWER THAN THE GFS. MREF IS ALSO SLOWER THAN THE OPERATIONAL GFS. USING A MREF/SREF BLEND PUTS THE COLD FRONT ALONG OR JUST ON THE INDIANA SIDE OF THE OHIO RIVER BY 12Z THURSDAY MORNING. AS A RESULT WILL LEAN TOWARDS THE WARMER MET NUMBERS FOR LOWS TONIGHT. BETWEEN THE UPPER SYSTEM MOVING OVERHEAD LATER TODAY AND THE COLD FRONT APPROACHING TONIGHT SHOWERS AND THUNDERSTORMS ARE A GOOD BET. THE STORM PREDICTION CENTER HAS PLACED LOCATIONS ALONG AND NORTH OF THE OHIO RIVER IN A SLIGHT RISK FOR SEVERE STORMS. IT APPEARS HOWEVER TO BE A RATHER MARGINAL SET-UP FOR SEVERE WEATHER. LIFTED INDICES AND SHOWALTER INDEX NUMBERS BOTTOMING OUT AROUND -1 OR -2 THIS AFTERNOON WITH TOTAL TOTALS OF 45 TO 50...WEAK CAPE...AND SHALLOW MID-LEVEL LAPSE RATES SUGGEST THUNDERSTORMS ARE A POSSIBILITY BUT THE CHANCE FOR SEVERE SEEMS SMALL. BEST TIME FOR THUNDERSTORMS WILL BE LATE THIS AFTERNOON AS SHEAR PEAKS. CHANCES SHOULD THEN DIMINISH FURTHER ONCE THE SUN SETS. LOW LEVEL JET DOES CRANK UP THIS AFTERNOON AND THE WET BULB ZERO HEIGHT WILL BE AROUND 9000 FEET SO THE STRONGEST STORMS MAY BE ABLE TO PRODUCE SOME GUSTY WINDS AND HAIL. TEMPERATURES TODAY WILL BE TRICKY. LOUISVILLE WAS STILL 70 DEGREES AT 100 AM BEFORE SHOWERS MOVED IN AND DROPPED THE TEMPERATURE TO 63...WITH MIDDLE 60S REPORTED THROUGHOUT THE REST OF THE FORECAST AREA AS WELL. AS OPPOSED TO YESTERDAY...TODAY WILL HAVE COPIOUS AMOUNTS OF CLOUD COVER. HOWEVER A FEW BREAKS WILL BE POSSIBLE BETWEEN THIS MORNING/S AND THIS AFTERNOON/S SHOWERS. WILL ALLOW READINGS TO CLIMB ABOUT TEN DEGREES...INTO THE MIDDLE 70S. 13 .LONG TERM (THURSDAY THROUGH TUESDAY)... THURSDAY THROUGH FRIDAY NIGHT... THIS PERIOD WILL BE THE MAIN FOCUS OF THE EXTENDED FORECAST AS DECENT COLD FRONT WILL DROP SOUTH AND BRING A PERIOD OF SHOWERS AND STORMS TO THE OHIO VALLEY. 00Z GFS AND NAM-WRF RUNS CONTINUE TO HAVE TIMING DIFFERENCES WITH THE ACTUAL FRONTAL PASSAGE. GFS SOLUTIONS CONTINUE TO BE CONSISTENT WITH PREVIOUS RUNS ON A THURSDAY MORNING FRONTAL PASSAGE WHILE THE NAM-WRF IS SOME 12 HOURS LATER. 21Z SREF SOLUTIONS ARE FAIRLY CONSISTENT WITH THE YESTERDAYS 09Z SOLUTION WHICH IS DOWN THE MIDDLE OF BOTH THE OP GFS AND NAM RUNS. THEREFORE WILL CONTINUE TO LEAN THE TOWARD THIS SOLUTION FOR THE FORECAST. USING THE 21Z SREF SOLUTION SFC FRONTAL BOUNDARY LOOKS TO CROSS THROUGH THE AREA DURING THE DAY ON THURSDAY. EXTENSIVE CLOUDINESS AND SCATTERED PRECIPITATION ARE EXPECTED THURSDAY MORNING AND WILL LIKELY LIMIT SFC BASED INSTABILITY. ADDITIONALLY...LAPSE RATES ARE NOT ALL THAT GREAT AS COOLER AIR ALOFT IS DISPLACED FURTHER NW OF THE AREA. LOW-LEVEL FLOW AHEAD OF THE FRONT STILL LOOKS TO BE IN THE AREA OF 35-40 KTS...THEREFORE SOME GUSTY WINDS WILL BE POSSIBLE WITH ANY CONVECTION THAT CAN GET GOING. HOWEVER...OVERALL THREAT OF ORGANIZED SEVERE APPEARS QUITE DIMINISHED AS OF THIS TIME. BEST FORCING WILL BE ALONG SAID FRONTAL BOUNDARY AND BASED ON 21Z SREF HAVE GONE AHEAD AND BUMPED POPS UP TO THE HIGH END OF THE LIKELY CATEGORY. TEMPERATURES FOR THURSDAY WILL BE A CHALLENGE DUE TO CLOUD COVER AND PRECIPITATION. I HAVE LOWERED TEMPS BY A DEGREE OR TWO WITH LOWER 60S ACROSS SOUTHERN INDIANA AND MID TO UPPER 60S ACROSS CENTRAL AND SOUTHERN KENTUCKY. I ANTICIPATE FALLING TEMPERATURES QUICKLY AFTER FRONTAL PASSAGE. LOWS THURSDAY NIGHT WILL DROP INTO THE UPPER 30S ACROSS SOUTHERN INDIANA AND PORTIONS OF NORTH CENTRAL KY. WARMER READINGS WILL BE FURTHER SOUTH ALONG THE KY/TN BORDER WITH MID TO UPPER 40S. FOR FRIDAY...POST FRONTAL PRECIPITATION WILL CONTINUE TO MOVE EAST AND OUT OF THE AREA. WILL MAINTAIN A SMALL CHANCE OF PRECIPITATION FOR FRIDAY MORNING ACROSS THE EASTERN SECTIONS. MOSTLY CLOUDY SKIES ARE EXPECTED THROUGH MUCH OF THE DAY WITH SOME PARTIAL CLEARING POSSIBLE BY LATE AFTERNOON. CLOUDS WILL KEEP TEMPS DOWN WITH HIGHS ONLY WARMING INTO THE UPPER 40S TO AROUND 50. A RETURN TO COLDER TEMPS IS EXPECTED FRIDAY NIGHT WITH OVERNIGHT LOWS DIPPING INTO THE UPPER 20S TO AROUND 30. SATURDAY THROUGH SUNDAY... MODEL CONSENSUS SOLUTION SUGGESTS DRY CONDITIONS THROUGH THIS PORTION OF THE FORECAST PERIOD. OHIO VALLEY TO REMAIN IN GENERAL NORTHWEST FLOW PATTERN. LAST FEW RUNS OF THE GFS HAVE BEEN SUGGESTING THAT WEAK VORT WITHIN THE FLOW MAY TRIGGER SOME LIGHT PRECIPITATION JUST TO OUR NORTHEAST DURING THE DAY ON SATURDAY. A STRONGER SYSTEM MAY DROP DOWN INTO THE REGION BY SUNDAY BRINGING LIGHT PRECIP. THERMAL PROFILES SUPPORT LIQUID PRECIPITATION AT THIS TIME. FOR NOW WILL HOLD OFF ON MAKING MAJOR ADJUSTMENTS TO THE FORECAST PERIOD AND WAIT TO SEE WHAT THE ENSEMBLES RUNS REVEAL. CURRENT FORECAST TEMPS LOOK OK FOR NOW...WITH HIGHS IN THE MID 40S IN THE NORTHEAST SECTIONS TO THE UPPER 40S AND LOWER 50S ACROSS THE SOUTHWEST. TEMPERATURES FOR SUNDAY MAY NEED TO BE TRENDED DOWN SOME AS 00Z GFS RAW NUMBERS SUPPORT COOLER TEMP TRENDS. -MJ SUNDAY NIGHT THROUGH TUESDAY... NO CHANGES MADE FOR THIS PART OF THE FORECAST PERIOD. PREVIOUS DISCUSSION FOLLOWS... BASING THE LAST TWO DAYS OF THE FCST PRIMARILY ON BLEND OF 0Z NCEP ENS MEAN AND ECMWF...WHICH SHOW UPPER TROF LIFTING NE WITH STRONG SW LOW LEVEL FLOW DEVELOPING OVER THE OHIO VALLEY. THIS WILL HELP TEMPS RISE QUICKLY BACK INTO THE 60S (ABOVE NORMAL) FOR MON AND TUES. A SFC FRONT DEPICTED BY BOTH MODEL SOLNS IS EXPECTED TO DROP S INTO THE OHIO VALLEY SOMETIME LATE MONDAY...PROVIDING A CHANCE FOR SHOWERS...SLIGHT CHANCES MONDAY...BETTER CHANCES INTO TUESDAY. THERE COULD BE SOME THUNDER INVOLVED AS WELL BUT AMT OF INSTABILITY THAT CAN DEVELOP IS QUESTIONABLE AT THIS TIME. CS && .AVIATION (12Z TAFS)... 40 KNOT WINDS SHOWING UP ON VWP AT FORT KNOX AT 2000 FEET AT 10Z. RECENT ACARS SOUNDING SHOWING 35 KNOTS AT THAT LEVEL. AS THE WINDS ALOFT DECREASE A BIT AND SURFACE WINDS INCREASE THE LLWS OVER THE REGION EARLY THIS MORNING WILL DIMINISH. WE WILL HAVE SEVERAL DRY HOURS BEFORE THE NEXT UPPER LEVEL DISTURBANCE COMES IN FROM THE SOUTHWEST AND BRINGS ANOTHER ROUND OF SHOWERS WITH IT. EXPECT SHOWERS AND THUNDERSTORMS NEAR THE TAF SITES LATE THIS AFTERNOON INTO EARLY THIS EVENING. THE BEST CHANCE FOR THUNDER WILL BE AFTER 21Z AND THIS IS REFLECTED IN THE TAFS BY INCLUDING A CB CLOUD TYPE. BEST CHANCES FOR SHOWERY WEATHER WILL BE AT SDF AND LEX AS THOSE LOCATIONS ARE INFLUENCED BY BOTH THE UPPER LEVEL DISTURBANCE AND A SURFACE COLD FRONT THAT WILL BE DROPPING SOUTHWARD INTO THE OHIO VALLEY. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION...CORR
NWS LOUISVILLE KY
628 AM EDT WED MAR 14 2007 .AVIATION (12Z TAFS)... 40 KNOT WINDS SHOWING UP ON VWP AT FORT KNOX AT 2000 FEET AT 10Z. RECENT ACARS SOUNDING SHOWING 35 KNOTS AT THAT LEVEL. AS THE WINDS ALOFT DECREASE A BIT AND SURFACE WINDS INCREASE THE LLWS OVER THE REGION EARLY THIS MORNING WILL DIMINISH. WE WILL HAVE SEVERAL DRY HOURS BEFORE THE NEXT UPPER LEVEL DISTURBANCE COMES IN FROM THE SOUTHWEST AND BRINGS ANOTHER ROUND OF SHOWERS WITH IT. EXPECT SHOWERS AND THUNDERSTORMS NEAR THE TAF SITES LATE THIS AFTERNOON INTO EARLY THIS EVENING. THE BEST CHANCE FOR THUNDER WILL BE AFTER 21Z AND THIS IS REFLECTED IN THE TAFS BY INCLUDING A CB CLOUD TYPE. BEST CHANCES FOR SHOWERY WEATHER WILL BE AT SDF AND LEX AS THOSE LOCATIONS ARE INFLUENCED BY BOTH THE UPPER LEVEL DISTURBANCE AND A SURFACE COLD FRONT THAT WILL BE DROPPING SOUTHWARD INTO THE OHIO VALLEY. 13 .SHORT TERM (TODAY AND TONIGHT)... UPPER VORT PRODUCING SCATTERED SHOWERS ACROSS THE LOUISVILLE FORECAST AREA AT 06Z WILL CONTINUE ITS MARCH TO THE NORTHEAST AND WILL TAKE ITS SHOWERS OUT OF OUR AREA EARLY THIS MORNING. WE SHOULD THEN HAVE SEVERAL MOSTLY DRY HOURS FROM MID MORNING INTO EARLY AFTERNOON. UPPER LOW OVER TEXAS WILL CONTINUE TO EDGE SLOWLY EAST...CROSSING TEXAS TODAY AND ENTERING THE LOWER MISSISSIPPI VALLEY TONIGHT. IT WILL SEND ANOTHER SMALL VORT MAX NORTHEAST TODAY...CROSSING CENTRAL KENTUCKY LATE THIS AFTERNOON AND THIS EVENING. THIS FEATURE WILL HELP TO SPARK OFF SHOWERS AND THUNDERSTORMS. IN ADDITION...TONIGHT AN EAST-WEST COLD FRONT WILL DROP SOUTH OUT OF THE MIDWEST AND GREAT LAKES INTO THE OHIO VALLEY. TIMING DIFFERENCES NOTED BY THE DAY SHIFT YESTERDAY CONTINUE...WITH THE NAM12 ABOUT 8 HOURS SLOWER THAN THE GFS. MREF IS ALSO SLOWER THAN THE OPERATIONAL GFS. USING A MREF/SREF BLEND PUTS THE COLD FRONT ALONG OR JUST ON THE INDIANA SIDE OF THE OHIO RIVER BY 12Z THURSDAY MORNING. AS A RESULT WILL LEAN TOWARDS THE WARMER MET NUMBERS FOR LOWS TONIGHT. BETWEEN THE UPPER SYSTEM MOVING OVERHEAD LATER TODAY AND THE COLD FRONT APPROACHING TONIGHT SHOWERS AND THUNDERSTORMS ARE A GOOD BET. THE STORM PREDICTION CENTER HAS PLACED LOCATIONS ALONG AND NORTH OF THE OHIO RIVER IN A SLIGHT RISK FOR SEVERE STORMS. IT APPEARS HOWEVER TO BE A RATHER MARGINAL SET-UP FOR SEVERE WEATHER. LIFTED INDICES AND SHOWALTER INDEX NUMBERS BOTTOMING OUT AROUND -1 OR -2 THIS AFTERNOON WITH TOTAL TOTALS OF 45 TO 50...WEAK CAPE...AND SHALLOW MID-LEVEL LAPSE RATES SUGGEST THUNDERSTORMS ARE A POSSIBILITY BUT THE CHANCE FOR SEVERE SEEMS SMALL. BEST TIME FOR THUNDERSTORMS WILL BE LATE THIS AFTERNOON AS SHEAR PEAKS. CHANCES SHOULD THEN DIMINISH FURTHER ONCE THE SUN SETS. LOW LEVEL JET DOES CRANK UP THIS AFTERNOON AND THE WET BULB ZERO HEIGHT WILL BE AROUND 9000 FEET SO THE STRONGEST STORMS MAY BE ABLE TO PRODUCE SOME GUSTY WINDS AND HAIL. TEMPERATURES TODAY WILL BE TRICKY. LOUISVILLE WAS STILL 70 DEGREES AT 100 AM BEFORE SHOWERS MOVED IN AND DROPPED THE TEMPERATURE TO 63...WITH MIDDLE 60S REPORTED THROUGHOUT THE REST OF THE FORECAST AREA AS WELL. AS OPPOSED TO YESTERDAY...TODAY WILL HAVE COPIOUS AMOUNTS OF CLOUD COVER. HOWEVER A FEW BREAKS WILL BE POSSIBLE BETWEEN THIS MORNING/S AND THIS AFTERNOON/S SHOWERS. WILL ALLOW READINGS TO CLIMB ABOUT TEN DEGREES...INTO THE MIDDLE 70S. 13 .LONG TERM (THURSDAY THROUGH TUESDAY)... THURSDAY THROUGH FRIDAY NIGHT... THIS PERIOD WILL BE THE MAIN FOCUS OF THE EXTENDED FORECAST AS DECENT COLD FRONT WILL DROP SOUTH AND BRING A PERIOD OF SHOWERS AND STORMS TO THE OHIO VALLEY. 00Z GFS AND NAM-WRF RUNS CONTINUE TO HAVE TIMING DIFFERENCES WITH THE ACTUAL FRONTAL PASSAGE. GFS SOLUTIONS CONTINUE TO BE CONSISTENT WITH PREVIOUS RUNS ON A THURSDAY MORNING FRONTAL PASSAGE WHILE THE NAM-WRF IS SOME 12 HOURS LATER. 21Z SREF SOLUTIONS ARE FAIRLY CONSISTENT WITH THE YESTERDAYS 09Z SOLUTION WHICH IS DOWN THE MIDDLE OF BOTH THE OP GFS AND NAM RUNS. THEREFORE WILL CONTINUE TO LEAN THE TOWARD THIS SOLUTION FOR THE FORECAST. USING THE 21Z SREF SOLUTION SFC FRONTAL BOUNDARY LOOKS TO CROSS THROUGH THE AREA DURING THE DAY ON THURSDAY. EXTENSIVE CLOUDINESS AND SCATTERED PRECIPITATION ARE EXPECTED THURSDAY MORNING AND WILL LIKELY LIMIT SFC BASED INSTABILITY. ADDITIONALLY...LAPSE RATES ARE NOT ALL THAT GREAT AS COOLER AIR ALOFT IS DISPLACED FURTHER NW OF THE AREA. LOW-LEVEL FLOW AHEAD OF THE FRONT STILL LOOKS TO BE IN THE AREA OF 35-40 KTS...THEREFORE SOME GUSTY WINDS WILL BE POSSIBLE WITH ANY CONVECTION THAT CAN GET GOING. HOWEVER...OVERALL THREAT OF ORGANIZED SEVERE APPEARS QUITE DIMINISHED AS OF THIS TIME. BEST FORCING WILL BE ALONG SAID FRONTAL BOUNDARY AND BASED ON 21Z SREF HAVE GONE AHEAD AND BUMPED POPS UP TO THE HIGH END OF THE LIKELY CATEGORY. TEMPERATURES FOR THURSDAY WILL BE A CHALLENGE DUE TO CLOUD COVER AND PRECIPITATION. I HAVE LOWERED TEMPS BY A DEGREE OR TWO WITH LOWER 60S ACROSS SOUTHERN INDIANA AND MID TO UPPER 60S ACROSS CENTRAL AND SOUTHERN KENTUCKY. I ANTICIPATE FALLING TEMPERATURES QUICKLY AFTER FRONTAL PASSAGE. LOWS THURSDAY NIGHT WILL DROP INTO THE UPPER 30S ACROSS SOUTHERN INDIANA AND PORTIONS OF NORTH CENTRAL KY. WARMER READINGS WILL BE FURTHER SOUTH ALONG THE KY/TN BORDER WITH MID TO UPPER 40S. FOR FRIDAY...POST FRONTAL PRECIPITATION WILL CONTINUE TO MOVE EAST AND OUT OF THE AREA. WILL MAINTAIN A SMALL CHANCE OF PRECIPITATION FOR FRIDAY MORNING ACROSS THE EASTERN SECTIONS. MOSTLY CLOUDY SKIES ARE EXPECTED THROUGH MUCH OF THE DAY WITH SOME PARTIAL CLEARING POSSIBLE BY LATE AFTERNOON. CLOUDS WILL KEEP TEMPS DOWN WITH HIGHS ONLY WARMING INTO THE UPPER 40S TO AROUND 50. A RETURN TO COLDER TEMPS IS EXPECTED FRIDAY NIGHT WITH OVERNIGHT LOWS DIPPING INTO THE UPPER 20S TO AROUND 30. SATURDAY THROUGH SUNDAY... MODEL CONSENSUS SOLUTION SUGGESTS DRY CONDITIONS THROUGH THIS PORTION OF THE FORECAST PERIOD. OHIO VALLEY TO REMAIN IN GENERAL NORTHWEST FLOW PATTERN. LAST FEW RUNS OF THE GFS HAVE BEEN SUGGESTING THAT WEAK VORT WITHIN THE FLOW MAY TRIGGER SOME LIGHT PRECIPITATION JUST TO OUR NORTHEAST DURING THE DAY ON SATURDAY. A STRONGER SYSTEM MAY DROP DOWN INTO THE REGION BY SUNDAY BRINGING LIGHT PRECIP. THERMAL PROFILES SUPPORT LIQUID PRECIPITATION AT THIS TIME. FOR NOW WILL HOLD OFF ON MAKING MAJOR ADJUSTMENTS TO THE FORECAST PERIOD AND WAIT TO SEE WHAT THE ENSEMBLES RUNS REVEAL. CURRENT FORECAST TEMPS LOOK OK FOR NOW...WITH HIGHS IN THE MID 40S IN THE NORTHEAST SECTIONS TO THE UPPER 40S AND LOWER 50S ACROSS THE SOUTHWEST. TEMPERATURES FOR SUNDAY MAY NEED TO BE TRENDED DOWN SOME AS 00Z GFS RAW NUMBERS SUPPORT COOLER TEMP TRENDS. -MJ SUNDAY NIGHT THROUGH TUESDAY... NO CHANGES MADE FOR THIS PART OF THE FORECAST PERIOD. PREVIOUS DISCUSSION FOLLOWS... BASING THE LAST TWO DAYS OF THE FCST PRIMARILY ON BLEND OF 0Z NCEP ENS MEAN AND ECMWF...WHICH SHOW UPPER TROF LIFTING NE WITH STRONG SW LOW LEVEL FLOW DEVELOPING OVER THE OHIO VALLEY. THIS WILL HELP TEMPS RISE QUICKLY BACK INTO THE 60S (ABOVE NORMAL) FOR MON AND TUES. A SFC FRONT DEPICTED BY BOTH MODEL SOLNS IS EXPECTED TO DROP S INTO THE OHIO VALLEY SOMETIME LATE MONDAY...PROVIDING A CHANCE FOR SHOWERS...SLIGHT CHANCES MONDAY...BETTER CHANCES INTO TUESDAY. THERE COULD BE SOME THUNDER INVOLVED AS WELL BUT AMT OF INSTABILITY THAT CAN DEVELOP IS QUESTIONABLE AT THIS TIME. CS && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1010 PM EDT THU MAR 16 2007 .SHORT TERM... WATER VAPOR LOOP SHOWS AN UPPER LOW MOVING EAST ACROSS THE GULF COAST AS A VIGOROUS SHORT WAVE DROPS SOUTHEAST ACROSS THE UPPER MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 120-150KT JET FROM THE UPPER MIDWEST NORTHEAST OVER MAINE. A SECOND 110-140KT JET EXTENDED FROM WESTERN CANADA SOUTHEAST ACROSS TH CENTRAL ROCKIES AND INTO THE PLAINS. 19Z SURFACE ANALYSIS PLACED A COLD FRONT SAGGING SOUTH THROUGH NORTHERN VIRGINIA...SOUTHWEST INTO THE PLAINS. A SECOND COLD FRONT WAS SAGGING SOUTH OF THE GREAT LAKES REGION. FIRST CONCERNING THE FLOOD WATCH. STEADY PRECIPITATION HAS SERVED TO SOAK THE GROUND THIS EVENING ACROSS THE REGION...WITH RAINFALL TOTALS THROUGH 00Z RANGING FROM ABOUT A TENTH OF AN INCH ACROSS THE SOUTHEAST FORECAST AREA TO NEAR A HALF INCH ACROSS THE WESTERN FORECAST AREA. NAM/GFS HAVE BEEN IN GOOD AGREEMENT THAT A CORRIDOR OF HEAVIER RAIN DEVELOPS FROM CENTRAL VIRGINIA ALONG THE INTERSTATE 95 CORRIDOR FRIDAY...ASSOCIATED WITH FRONTOGENETIC FORCING AS THE COASTAL SYSTEM DEEPENS OFF THE DELMARVA. HERE...THE 15Z SHORT RANGE ENSEMBLES HAVE A 70 PERCENT PROBABILITY OF OVER AN INCH IN 12 HOURS...AND LOW PROBABILITY OF GREATER THAN TWO INCHES IN 12 HOURS. CREEKS...STREAMS AND URBAN AREAS MAY SEE A RESPONSE FRIDAY AFTERNOON. REGARDING WINTER WEATHER...THERE IS MUCH MORE THAT IS UNKNOWN AT THIS POINT. 12Z/18Z NAM/GFS HAVE DIFFERING TRACKS OF LOWER LEVEL FEATURES DURING THE SHORT TERM...WHICH IS CONTRIBUTING TO SIGNIFICANT DIFFERENCES IN THE LOWER LEVEL THERMODYNAMIC FIELDS. 15Z SHORT RANGE ENSEMBLES INDICATE LITTLE MORE THAN THAT THERE IS A SIGNIFICANT SPREAD IN 850MB TEMPERATURES ACROSS THE REGION...WITH NO CLUSTERING (A CONCERN AT THIS SHORT RANGE TO THE EVENT). USING THE MEAN 15Z SHORT RANGE ENSEMBLE 850MB TEMPERATURES AS A PROXY FOR THE ENTIRE LOW LEVEL THERMAL FIELD...LOW LEVEL THERMODYNAMIC FIELD IS LIKELY TO COOL TO FREEZING FIRST ACROSS THE FAR NORTHWEST FORECAST AREA. DEFORMATION AREA BETWEEN THE TWO SYNOPTIC STREAMS IS DEVELOPING ON SATELLITE AND RADAR ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY. THIS WILL BE AN IMPORTANT SOURCE OF LIFT ACROSS THE NORTHWEST FORECAST AREA AS THE COASTAL SYSTEM DEVELOPS FRIDAY. WITH SNOW REPORTED AT KJST THIS EVENING...AND THE 00Z KPBZ RAOB TO VERIFY...LOW LEVEL THERMAL FIELD APPEARS SUFFICIENTLY COOL TO SUPPORT SNOW VERY CLOSE TO THE NORTHWEST FORECAST AREA AT THIS TIME...AS DEFORMATION AREA APPROACHES BEGINNING EARLY THIS MORNING. FURTHER TO THE SOUTHEAST AND EAST...WITH SUCH SIGNIFICANT VARIANCE REGARDING THE LOWER LEVEL THERMAL STRUCTURE OF THE ATMOSPHERE...AND A LATER ARRIVAL OF FORCING...HELD OFF ON ANY UPGRADES. THE NEXT SHIFT WILL HAVE THE 00Z RAOBS AND MODELS TO GET A BETTER HANDLE ON THINGS. ONE LAST TWIST TO THE FORECAST RESTS IN THE HIGHER TERRAIN OF VIRGINIA...WHERE THERE IS SOME CHANCE OF SEEING FREEZING RAIN OVERNIGHT. GIVEN THE LOW CONFIDENCE OF LOW LEVEL THERMAL FIELDS AND ISOLATED NATURE...OPTED NOT TO INCLUDE IN THE FORECAST...BUT IT CERTAINLY BEARS WATCHING. && .AVIATION... CEILINGS DETERIORATE AS ISENTROPIC LIFT INCREASES OVERNIGHT. N/NE WINDS WILL BECOME GUSTY AGAIN FRIDAY ON THE BACKSIDE OF THE COASTAL STORM...AS PRECIPITATION TENDS TO BECOME MORE FROZEN WITH TIME. && .MARINE... 12Z ETA/GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL BE NEAR 20KT THROUGH AT LEAST TONIGHT. 12Z NAM/GFS PROXIMITY FORECAST SOUNDINGS INDICATE ADDITIONAL WIND GUST POTENTIAL OF UP TO 25 KTS OVERNIGHT. && .TIDES... WATER LEVELS ARE A QUARTER TO THREE QUARTERS OF A FOOT BELOW ASTRONOMICAL PREDICTIONS. BOTH THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND NOAA EXTRATROPICAL STORM SURGE MODELS INDICATE NEGATIVE WATER DEPARTURES WILL CONTINUE TO GRADUALLY INCREASE THROUGH FRIDAY. THE LUNAR CYCLE IS WANING TOWARD A NEW MOON (14 PERCENT FULL). && .LWX WATCHES/WARNINGS/ADVISORIES... DC...FLOOD WATCH FROM 8 AM EDT FRIDAY THROUGH FRIDAY EVENING FOR DCZ001. MD...FLOOD WATCH FROM 8 AM EDT FRIDAY THROUGH FRIDAY EVENING FOR MDZ004>007-009>011-013-014-016>018. WINTER STORM WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR MDZ003>006. WINTER STORM WARNING FROM 4 AM TO 10 PM EDT FRIDAY FOR MDZ501- 502. VA...FLOOD WATCH FROM 8 AM EDT FRIDAY THROUGH FRIDAY EVENING FOR VAZ025-026-029-036>042-050>057. WINTER STORM WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR VAZ027-028-030-031-042. WV...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR WVZ050>053-055-502. WINTER STORM WARNING FROM 4 AM TO 10 PM EDT FRIDAY FOR WVZ501- 503-504. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT SATURDAY NIGHT FOR ANZ530>537. && $$ SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1154 PM EDT THU MAR 15 2007 .AVIATION...MID CLOUD COVER EXPECTED TO PERSIST THROUGH THE NIGHT...WITH DRY LOWER LAYERS KEEPING PRECIPITATION AT BAY. LOW LEVEL EASTERLY FLOW OFF LAKE HURON COMBINED WITH 925MB TEMPERATURES AROUND -11C RAISES SOME CONCERN FOR MVFR CEILINGS AT APN/PLN. SURFACE DEW POINTS STILL IN THE SINGLE DIGITS ACROSS NORTHEAST LOWER WHICH IMPLIES CBL STILL TOO DRY TO SUPPORT CLOUD DEVELOPMENT. WILL MAINTAIN TEMPO GROUPS FOR POSSIBILITY OF SC DEVELOPMENT THROUGH MIDDAY OR SO...AT THIS POINT THINK IT IS A LOW PROBABILITY EVENT. JPB && .PREV DISCUSSION... /ISSUED 950 PM EDT THU MAR 15 2007/ UPDATE...WATER VAPOR IMAGERY SHOWING SHORT WAVE TROUGH OVER EASTERN MN...MID/HIGH CLOUDS AHEAD OF THIS FEATURE HAVE OVERSPREAD NORTHERN MI. MAIN AREA OF PRECIPITATION CONCENTRATED JUST AHEAD OF THIS WAVE ACROSS EASTERN MN/FAR NORTHWEST WI...LOWER LAYERS QUITE A BIT DRIER TO THE EAST PER 00Z RAOBS AND AIRCRAFT SOUNDINGS (DEW POINT DEPRESSIONS BELOW 650MB GENERALLY ABOVE 10C). BETTER COMBINATION OF LOW/MID LEVEL MOISTURE AND INSTABILITY ACROSS MN (850-500MB LAPSE RATES AT OR ABOVE MOIST ADIABATIC AT MPX/INL) PROVIDING A LITTLE CONVECTIVE BOOST TO UPSTREAM PRECIPITATION. MID CLOUDS WILL HANG ON THROUGH THE NIGHT...DRY LOW LAYERS WILL ALSO HANG ON AND SHOULD PRECLUDE MUCH IN THE WAY OF PRECIP POTENTIAL. MOSTLY CLOUDY SHOULD COVER IT. JPB /ISSUED 321 PM EDT THU MAR 15 2007/ LATEST RUC ANALYSIS AND VIS/IR/WV IMAGERY SHOW SURFACE HIGH PRESSURE CENTERED OVER CENTRAL ONTARIO AND A LONG COLD FRONT DRAPED FROM THE GULF COAST ACROSS THE CENTRAL APPALACHIANS TO THE NORTHEAST UNITED STATES. LARGE SWATH OF CLOUDS TO THE NORTH OF THIS FRONT DUE TO DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 140KT JET STREAK HAS CLEARED THE CWA TO SOUTHEAST LOWER MICHIGAN. WITH LAKE CLOUDS OVER NORTHEAST LOWER EVAPORATING AS A RESULT OF THE DRY AIR AND MIXING UNDER A MARCH SUN...THE CWA IS ENJOYING A SHORT-LIVED MOSTLY SUNNY SKY ATTM. HOWEVER...MID AND HIGH CLOUDS ASSOCIATED WITH A SHORTWAVE SPINNING OVER THE NORTHERN PLAINS ARE QUICKLY ADVANCING ACROSS THE WESTERN GREAT LAKES. AS THIS WAVE APPROACHES NORTHERN MICHIGAN...LIGHT PRECIP CHANCES ARE THE MAIN FORECAST CONCERN THROUGH TOMORROW. TONIGHT...MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH THE SHORTWAVE OVER THE NORTHERN PLAINS WILL SPREAD OVER THE CWA TONIGHT. HOWEVER...DRY AIR EMANATING FROM HIGH PRESSURE MOVING OVER ONTARIO AND INTO QUEBEC WILL PREVENT MUCH MOISTURE FROM REACHING BELOW ABOUT 700MB. THIS DRY AIR WILL KEEP MOST OF THE CWA PRECIP FREE. THE EXCEPTION MAY BE OVER NORTHEAST LOWER WHERE 1000-850MB WINDS WILL REMAIN OUT OF THE EAST. EVEN THOUGH MODELS PEG INVERSION HEIGHTS AROUND 3KFT...THE LONG FETCH OVER LAKE HURON COMBINED WITH DELTA T/S AROUND 10C MAY MODIFY THE BOUNDARY LAYER ENOUGH TO TRIGGER SOME FLURRIES OVERNIGHT AND EARLY TOMORROW MORNING. OTHER THAN THIS MINOR DETAIL...CLOUDS WILL BE ON THE INCREASE WITH LOWS BOTTOMING OUT MOSTLY IN THE TEENS. TOMORROW...SHORTWAVE WILL MOVE WSW ACROSS THE SOUTHERN GREAT LAKES. THE WEAK SURFACE REFLECTION OF THIS WAVE...HOWEVER...WILL GET ABSORBED INTO THE STRONGER FLOW BETWEEN THE STRONG SURFACE HIGH OVER QUEBEC AND THE DEVELOPING COASTAL LOW OVER THE CAROLINAS. ALTHOUGH PLENTY OF MID-LEVEL MOISTURE WILL BE ACCOMPANYING THIS WAVE...DRY NE/E LOW LEVEL FLOW WILL KEEP A WEDGE OF DRY AIR CENTERED AROUND 850MB WITH DEW POINT DEPRESSIONS UPWARDS OF 20C (12C EASTERN UPPER). THIS DRY WEDGE IS EXPECTED TO PREVENT MOST OF THE PRECIP FALLING OUT OF THE MID-LEVEL CLOUD DECK FROM REACHING THE GROUND. THE EXCEPTION MAY BE OVER NE LOWER WHERE ENE FLOW WITH DELTA T/S AROUND 10C MAY PRODUCE SOME FLURRIES...ESPECIALLY DURING THE MORNING BEFORE MIXING STARTS...AND EASTERN UPPER WHERE MORE MOISTURE WILL RESIDE. TEMPERATURES WILL BE SLIGHTLY WARMER DESPITE THE CLOUD COVER... RANGING FROM NEAR 30 TO THE MIDDLE 30S. MPC RATHER QUIET BUT CHILLY WEEKEND IN STORE FOR NORTHERN MICHIGAN WITH LARGE UPPER LOW WRAPPING UP OVER NEW ENGLAND AND DRY N/NW FLOW ACROSS THE GREAT LAKES. SHORTWAVE TROF OVER THE NORTHERN PLAINS TRIES TO MOVE INTO THE AREA...BUT REALLY JUST FALLS APART AS IT GETS ABSORBED INTO LARGER UPPER SYSTEM OVER NEW ENGLAND. A COLD ST. PATRICKS DAY IN STORE FOR THE AREA...WITH A FEW LIGHT LAKE EFFECT SNOW SHOWERS POSSIBLE IN N/NW FLOW AREAS. MOISTURE IS VERY LIMITED...BUT ENOUGH COLD AIR TO PROBABLY GENERATE SOME FLURRIES OR VERY LIGHT SNOW SHOWERS WEST OF I-75. ON SUNDAY...CLOUDS WILL INCREASE FROM WEST TO EAST AS BROAD ISENTROPIC ASCENT ON THE 310K SURFACE INCREASES IN ADVANCE OF NEXT CLIPPER SYSTEM. THE ATMOSPHERE WILL MOISTEN UP SUNDAY AFTERNOON AND EVENING...WITH LIGHT SNOW LIKELY OVERSPREADING THE AREA. BEST FORCING REMAINS NORTH OF M-32...BUT MOST AREAS SHOULD SEE AT LEAST SOME QPF /AND VERY LIGHT ACCUMS OF SNOW/. CLIPPER MOVES THROUGH THE NORTHERN LAKES ON MONDAY USHERING IN ONE LAST SURGE OF MODIFIED ARCTIC AIR FOR A BRIEF VISIT TO THE GREAT LAKES. GFS IS MOST BULLISH WITH THE COLD AIR...SHOWING 850MB TEMPERATURES FALLING TO -14 TO -18 DEGC MONDAY AFTERNOON. ECMWF DOES NOT BRING THE COLD AIR AS FAR SOUTH...BUT STILL INDICATES 850MB THERMAL TROF SWINGING ACROSS THE AREA. I WILL NOT GET TOO DETAILED WITH THINGS THIS FAR OUT...BUT GFS SOLUTION WOULD RESULT IN N/NW FLOW LAKE EFFECT SNOW SHOWERS MONDAY AFTERNOON/NIGHT AND GUSTY WINDS. COLD AIR BEGINS TO RETREAT ON TUESDAY AS LARGE SURFACE HIGH PRESSURE SLIDES TOWARD THE EAST COAST AND WARMER RETURN FLOW BEGINS. THIS PATTERNS STRENGTHENS AND CONTINUES ON WEDNESDAY...PUSHING HIGHS INTO THE 40S. A BROAD AND INCREASINGLY MOIST SOUTHWEST FLOW WILL DEVELOP ACROSS THE CENTER OF THE COUNTRY INTO THE GREAT LAKES AS WE HEAD TOWARD THE END OF NEXT WEEK...WITH BLOCKING HIGH OVER THE WESTERN ATLANTIC RESULTING IN LITTLE W-E PROGRESSION OF SYSTEMS. SO INCREASING CHANCES OF SHOWERS /TSTMS?/ FOR WEDNESDAY NIGHT THROUGH THE END OF THE WEEK WITH TEMPERATURES ABOVE NORMAL /GENERALLY 45 TO 55. && .APX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH...THROUGH FRIDAY EVENING...MIZ042. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1035 PM EDT THU MAR 15 2007 .UPDATE... MAIN FCST ISSUE OVERNIGHT IS SNOW COVERAGE/AMOUNTS. WATER VAPOR IMAGERY SHOWS A WELL-DEFINED SHORTWAVE DROPPING ESE THRU ERN MN. OVER THE LAST COUPLE OF HRS...VORT MAX HAS REDEVELOPED TO THE S TOWARD KMPX. SHIELD OF SNOW ASSOCIATED WITH SHORTWAVE IS SPREADING THRU FAR NW WI...BUT THERE IS A TREND FOR DECREASING COVERAGE AND INTENSITY OF SNOW WITH TIME PER KDLH RADAR. THIS IS DUE TO VORT REDEVELOPING SOUTHWARD. -SN HAS RECENTLY SLIPPED INTO FAR WRN UPPER MI IN THE VCNTY OF KIWD. OTHERWISE...DRY WEATHER IS PREVAILING ACROSS THE FCST AREA THIS EVENING THOUGH THERE MAY BE SOME LINGERING FLURRIES ON THE KEWEENAW PENINSULA UNDER ERLY FLOW WITH OVERLAKE INSTABILITY JUST SUFFICIENT FOR LES (LATE AFTN TAMDAR SOUNDING FROM KCMX SHOWED -14C AT 891MB). COMPARED TO KCMX SOUNDING...LATE AFTN TAMDAR SOUNDING FROM KSAW SHOWED DRIER AIR ABOVE INVERSION. DWPT DEPRESSIONS WERE 20C FROM AROUND 875MB TO AROUND 825MB. BASED ON RECENT TRENDS OF VORT REDEVELOPING FARTHER S...EXPECT SHIELD OF SNOW SPREADING INTO FAR WRN UPPER MI TO CONTINUE TO WEAKEN AS IT MOVES ESE. SO...FLAVOR OF INHERITED FCST IS ON TRACK WITH HIGHEST POPS EXTENDING THRU ONTONAGON/GOGEBIC COUNTIES AND THEN TRAILING OFF TO THE E TO NO MENTION OF SNOW OVER THE ERN FCST AREA. WOULD EXPECT ACCUMULATIONS OVER THE FAR W (KIWD TOWARD WATERSMEET) TO BE AROUND 1 INCH. PROVIDING THE NRN EDGE OF WEAKENING FORCING DOES NOT FADE COMPLETELY BEFORE REACHING ERN LAKE SUPERIOR...LES (-SHSN/FLURRIES) MAY REDEVELOP INTO THE KEWEENAW UNDER LIGHT ERLY LOW-LEVEL FLOW. AS FOR TEMPS...WILL RAISE MINS A FEW DEGREES IN MANY AREAS AS CLOUD COVER WILL KEEP TEMPS UP...PROBABLY NO LWR THAN 10F IN EVEN THE COLDEST LOCATIONS WEST. HIGHER CLOUD DECKS OVER THE E SHOULD RESULT IN LOWEST TEMPS THERE (5-10F). && .PREV DISCUSSION (ISSUED AT 423 PM EDT)... MAIN FCST CONCERN IS CHC SNOW OF SNOW TONIGHT INTO FRI WITH CLIPPER SYSTEM DIVING DOWN FROM THE NRN PLAINS. TONIGHT...AS THE STRONG SHORTWAVE APPROACHES FROM WRN MN...ALL MODELS SHOW MODERATE TO STRONG Q-VECT CONV SPREADING ACROSS WEST AND CENTRAL UPR MI ALONG WITH STEEP 700-500 MB LAPSE RATES OF 7.5-8C. STEEP ISENTROPIC ASCENT ON THE 280K SFC IS ALSO NOTED AHEAD OF THE SHORTWAVE AND THIS FORCING IS FOCUSED INTO GOGEBIC-ONTONAGON AND IRON COUNTIES LATER THIS EVENING. LOOK FOR THESE STRONG DYNAMICS TO OVERCOME VERY DRY AIR IN PLACE AS NOTED ON 12Z KGRB AND KMPX SNDGS. THUS...WILL KEEP CHC POPS IN MOST WEST AND CENTRAL COUNTIES EXCEPT WILL BUMP UP POPS TO LIKELY OVER GOGEBIC-ONTONAGON AND IRON COUNTIES. EXPECT SOME LOCATIONS IN THESE SW COUNTIES TO RECEIVE 1-2" OF NEW SNOW TONIGHT. EXPECT LES OVER MQT COUNTY TO DIMINISH AS FLOW VEERS FROM NE TO E...ALTHOUGH LIGHT LES WILL LIKELY CONTINUE OVER THE KEWEENAW THROUGH MUCH OF THE NIGHT. FRIDAY...BEST DYNAMICS WITH SHORTWAVE SLIDE E OF AREA ALTHOUGH MID-LVL TROF AND 5H COLD POOL OF -40C TEMPS REMAIN ALONG WITH ASSOC 700-500 MB LAPSE RATES OF 7.5-8C. SO WILL MAINTAIN CHC POPS FOR POSSIBLE FORMATION OF CONVECTIVE SHSN OVER WEST AND CENTRAL COUNTIES WITH A SLIGHT CHC IN THE E. FRI NIGHT INTO SAT...GIVEN WEAK NRLY FLOW CONTINUING...850 MB TEMPS MDL CONSENSUS TEMPS AROUND -13C AND MID LVL TROF AXIS STILL NEARBY OR JUST EAST OF THE AREA...WILL CONTINUE SLIGHT CHC OF LIGHT SNOW SHOWERS OVER NORTH UPPER MI. ALSO THERE IS A POTENTIAL THAT WEAK SHORTWAVES MOVING DOWN IN NW FLOW ON SAT COULD ENHANCE SNOW CHCS. SUN AND TUE...THE 12Z GFS STILL LOOKS TO BE AN FAST OUTLIER WITH THE NEXT STRONG SHORTWAVE APPROACHING THE UPR GREAT LAKES. WILL CONTINUE TO FOLLOW MORE CONISTENT ECMWF AND GLBL CANADIAN MODELS WITH TIMING OF SYSTEM AND ASSOC PCPN. THESE MODELS WOULD SUGGEST THAT LIGHT SNOW COULD MOVE IN LATE SUN INTO WEST AND CENTRAL COUNTIES AND THEN SPREAD E ACROSS THE REST OF THE CWFA SUN NIGHT. AS FRONT APPROACHES AND PCPN WILL TRANSITION TO SHOWERS WITH TEMPS AND THICKNESSES SUGGESTING SNOW SHOWERS ACROSS THE NRN TIER AND A MIX OF RAIN/SNOW SHOWERS SOUTH. GLOBAL CANADIAN 850 MB TEMPS OF -12 TO -13C IMMEDIATELY BEHIND THE FRONT...COULD KEEP SOME LINGERING LES ALONG THE NRN TIER MON NIGHT BEFORE BEFORE HIGH PRES BUILDS IN AND DRIES THINGS OUT FOR TUE. WED AND THU...PATTERN TRANSITION IN WORKS AS DEEP MID-LVL TROF IS FCST TO DEVELOP OVER THE WRN CONUS WITH BROAD RDGG OVER THE ERN CONUS. STRONG WAA BRINGS ON WED AHEAD OF DEVELOPING SFC TROF OVER THE PLAINS. 850 MB TEMPS RISE TO 9/10C BY LATE WED AS ECMWF SHOWS A WARM FRONT MOVES ACROSS THE AREA. THREW IN LOW CHC POPS FOR RAIN ACROSS ENTIRE CWFA ON WED. BELIEVE...THERE COULD BE A LULL IN RAIN CHCS WED NIGHT AS THE WARM FRONT MOVES WELL NORTH OF REGION. AS THE COLD FRONT MOVES IN ON THU PER ECMWF AND GFS...WILL SEE RAIN CHCS RETURN. SHOWALTER DO LOWER IN THE AFTERNOON ALTHOUGH ZERO OR SUBZERO C VALUES STILL LOOK LIKE THEY STAY WELL S INTO WI SO WILL KEEP THUNDER MENTION OUT FOR NOW. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) VOSS (PREV DISCUSSION)
AREA FORECAST DISCUSSION
NWS GAYLORD MI
950 PM EDT THU MAR 15 2007 .UPDATE...WATER VAPOR IMAGERY SHOWING SHORT WAVE TROUGH OVER EASTERN MN...MID/HIGH CLOUDS AHEAD OF THIS FEATURE HAVE OVERSPREAD NORTHERN MI. MAIN AREA OF PRECIPITATION CONCENTRATED JUST AHEAD OF THIS WAVE ACROSS EASTERN MN/FAR NORTHWEST WI...LOWER LAYERS QUITE A BIT DRIER TO THE EAST PER 00Z RAOBS AND AIRCRAFT SOUNDINGS (DEW POINT DEPRESSIONS BELOW 650MB GENERALLY ABOVE 10C). BETTER COMBINATION OF LOW/MID LEVEL MOISTURE AND INSTABILITY ACROSS MN (850-500MB LAPSE RATES AT OR ABOVE MOIST ADIABATIC AT MPX/INL) PROVIDING A LITTLE CONVECTIVE BOOST TO UPSTREAM PRECIPITATION. MID CLOUDS WILL HANG ON THROUGH THE NIGHT...DRY LOW LAYERS WILL ALSO HANG ON AND SHOULD PRECLUDE MUCH IN THE WAY OF PRECIP POTENTIAL. MOSTLY CLOUDY SHOULD COVER IT. JPB && AVIATION...SHORT WAVE TROUGH OVER MN WILL HEAD SOUTHEAST ACROSS WI TONIGHT. THIS FEATURE WILL CONTINUE TO SPREAD MID/HIGH CLOUDS ACROSS NORTHERN MI...DRY LOW LEVEL EASTERLY FLOW EXPECTED TO KEEP PRECIPITATION AT BAY. SOME CONCERN ABOUT MVFR LEVEL CEILINGS AT APN AND PERHAPS PLN DUE TO SC FLOATING IN OFF LAKE HURON WITH 925MB TEMPERATURES AROUND -11C. LOW LEVELS MAY BE TOO DRY TO SUPPORT CLOUD DEVELOPMENT...SURFACE DEW POINTS CURRENTLY BELOW TEMPERATURES AT THE TOP OF THE CBL A DEFINITE NEGATIVE WITH REGARDS TO CONVECTIVE CLOUD DEVELOPMENT. THIS COULD CHANGE WITH A SHIFT IN WINDS FROM NORTHEAST TO EAST AND THUS BRING ABOUT A LONGER OVER-WATER TRAJECTORY...BUT FOR NOW WILL ONLY TEMPO IN MVFR CEILINGS ROUGHLY BETWEEN MIDNIGHT AND NOON AND SEE HOW SURFACE DEW POINTS RESPOND. JPB PREV DISCUSSION... /ISSUED 321 PM EDT THU MAR 15 2007/ LATEST RUC ANALYSIS AND VIS/IR/WV IMAGERY SHOW SURFACE HIGH PRESSURE CENTERED OVER CENTRAL ONTARIO AND A LONG COLD FRONT DRAPED FROM THE GULF COAST ACROSS THE CENTRAL APPALACHIANS TO THE NORTHEAST UNITED STATES. LARGE SWATH OF CLOUDS TO THE NORTH OF THIS FRONT DUE TO DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 140KT JET STREAK HAS CLEARED THE CWA TO SOUTHEAST LOWER MICHIGAN. WITH LAKE CLOUDS OVER NORTHEAST LOWER EVAPORATING AS A RESULT OF THE DRY AIR AND MIXING UNDER A MARCH SUN...THE CWA IS ENJOYING A SHORT-LIVED MOSTLY SUNNY SKY ATTM. HOWEVER...MID AND HIGH CLOUDS ASSOCIATED WITH A SHORTWAVE SPINNING OVER THE NORTHERN PLAINS ARE QUICKLY ADVANCING ACROSS THE WESTERN GREAT LAKES. AS THIS WAVE APPROACHES NORTHERN MICHIGAN...LIGHT PRECIP CHANCES ARE THE MAIN FORECAST CONCERN THROUGH TOMORROW. TONIGHT...MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH THE SHORTWAVE OVER THE NORTHERN PLAINS WILL SPREAD OVER THE CWA TONIGHT. HOWEVER...DRY AIR EMANATING FROM HIGH PRESSURE MOVING OVER ONTARIO AND INTO QUEBEC WILL PREVENT MUCH MOISTURE FROM REACHING BELOW ABOUT 700MB. THIS DRY AIR WILL KEEP MOST OF THE CWA PRECIP FREE. THE EXCEPTION MAY BE OVER NORTHEAST LOWER WHERE 1000-850MB WINDS WILL REMAIN OUT OF THE EAST. EVEN THOUGH MODELS PEG INVERSION HEIGHTS AROUND 3KFT...THE LONG FETCH OVER LAKE HURON COMBINED WITH DELTA T/S AROUND 10C MAY MODIFY THE BOUNDARY LAYER ENOUGH TO TRIGGER SOME FLURRIES OVERNIGHT AND EARLY TOMORROW MORNING. OTHER THAN THIS MINOR DETAIL...CLOUDS WILL BE ON THE INCREASE WITH LOWS BOTTOMING OUT MOSTLY IN THE TEENS. TOMORROW...SHORTWAVE WILL MOVE WSW ACROSS THE SOUTHERN GREAT LAKES. THE WEAK SURFACE REFLECTION OF THIS WAVE...HOWEVER...WILL GET ABSORBED INTO THE STRONGER FLOW BETWEEN THE STRONG SURFACE HIGH OVER QUEBEC AND THE DEVELOPING COASTAL LOW OVER THE CAROLINAS. ALTHOUGH PLENTY OF MID-LEVEL MOISTURE WILL BE ACCOMPANYING THIS WAVE...DRY NE/E LOW LEVEL FLOW WILL KEEP A WEDGE OF DRY AIR CENTERED AROUND 850MB WITH DEW POINT DEPRESSIONS UPWARDS OF 20C (12C EASTERN UPPER). THIS DRY WEDGE IS EXPECTED TO PREVENT MOST OF THE PRECIP FALLING OUT OF THE MID-LEVEL CLOUD DECK FROM REACHING THE GROUND. THE EXCEPTION MAY BE OVER NE LOWER WHERE ENE FLOW WITH DELTA T/S AROUND 10C MAY PRODUCE SOME FLURRIES...ESPECIALLY DURING THE MORNING BEFORE MIXING STARTS...AND EASTERN UPPER WHERE MORE MOISTURE WILL RESIDE. TEMPERATURES WILL BE SLIGHTLY WARMER DESPITE THE CLOUD COVER... RANGING FROM NEAR 30 TO THE MIDDLE 30S. MPC RATHER QUIET BUT CHILLY WEEKEND IN STORE FOR NORTHERN MICHIGAN WITH LARGE UPPER LOW WRAPPING UP OVER NEW ENGLAND AND DRY N/NW FLOW ACROSS THE GREAT LAKES. SHORTWAVE TROF OVER THE NORTHERN PLAINS TRIES TO MOVE INTO THE AREA...BUT REALLY JUST FALLS APART AS IT GETS ABSORBED INTO LARGER UPPER SYSTEM OVER NEW ENGLAND. A COLD ST. PATRICKS DAY IN STORE FOR THE AREA...WITH A FEW LIGHT LAKE EFFECT SNOW SHOWERS POSSIBLE IN N/NW FLOW AREAS. MOISTURE IS VERY LIMITED...BUT ENOUGH COLD AIR TO PROBABLY GENERATE SOME FLURRIES OR VERY LIGHT SNOW SHOWERS WEST OF I-75. ON SUNDAY...CLOUDS WILL INCREASE FROM WEST TO EAST AS BROAD ISENTROPIC ASCENT ON THE 310K SURFACE INCREASES IN ADVANCE OF NEXT CLIPPER SYSTEM. THE ATMOSPHERE WILL MOISTEN UP SUNDAY AFTERNOON AND EVENING...WITH LIGHT SNOW LIKELY OVERSPREADING THE AREA. BEST FORCING REMAINS NORTH OF M-32...BUT MOST AREAS SHOULD SEE AT LEAST SOME QPF /AND VERY LIGHT ACCUMS OF SNOW/. CLIPPER MOVES THROUGH THE NORTHERN LAKES ON MONDAY USHERING IN ONE LAST SURGE OF MODIFIED ARCTIC AIR FOR A BRIEF VISIT TO THE GREAT LAKES. GFS IS MOST BULLISH WITH THE COLD AIR...SHOWING 850MB TEMPERATURES FALLING TO -14 TO -18 DEGC MONDAY AFTERNOON. ECMWF DOES NOT BRING THE COLD AIR AS FAR SOUTH...BUT STILL INDICATES 850MB THERMAL TROF SWINGING ACROSS THE AREA. I WILL NOT GET TOO DETAILED WITH THINGS THIS FAR OUT...BUT GFS SOLUTION WOULD RESULT IN N/NW FLOW LAKE EFFECT SNOW SHOWERS MONDAY AFTERNOON/NIGHT AND GUSTY WINDS. COLD AIR BEGINS TO RETREAT ON TUESDAY AS LARGE SURFACE HIGH PRESSURE SLIDES TOWARD THE EAST COAST AND WARMER RETURN FLOW BEGINS. THIS PATTERNS STRENGTHENS AND CONTINUES ON WEDNESDAY...PUSHING HIGHS INTO THE 40S. A BROAD AND INCREASINGLY MOIST SOUTHWEST FLOW WILL DEVELOP ACROSS THE CENTER OF THE COUNTRY INTO THE GREAT LAKES AS WE HEAD TOWARD THE END OF NEXT WEEK...WITH BLOCKING HIGH OVER THE WESTERN ATLANTIC RESULTING IN LITTLE W-E PROGRESSION OF SYSTEMS. SO INCREASING CHANCES OF SHOWERS /TSTMS?/ FOR WEDNESDAY NIGHT THROUGH THE END OF THE WEEK WITH TEMPERATURES ABOVE NORMAL /GENERALLY 45 TO 55. && .APX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH...THROUGH FRIDAY EVENING...MIZ042. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
930 PM CDT THU MAR 15 2007 .UPDATE...FOR MOST PART FORECAST ON TRACK. SIG VORT PRODUCING LINE OF SNOW SHOWERS NOW MOVING THROUGH WEST CENTRAL WI. CONVECTIVE LOOK TO LINE. MID LEVEL LAPSE RATES 7 TO 7.5 OVER WESTERN WI...BEST INSTABILITY TO SHIFT INTO SOUTHERN WI OVERNIGHT. A QUICK ONE INCH OF ACCUMULATION LIKELY WITH LINE ATTM. EVENING SOUNDING OUT OF GRB AND ACARS SOUNDING FROM CWA SHOWS VERY DRY ATMOSPHERE OUT AHEAD OF THIS LINE...NOT BODING WELL FOR MAINTENANCE OF LINE. RETURNS AHEAD OF LINE DRYING UP ON RADARS. SO STAYED DRY/LOW CHANCE EAST WITH AMOUNTS LESS THAN AN INCH EXPECTED OVER CENTRAL ZONES. ADJUSTED TEMPS IN GRIDS WITH MINS JUST ABOUT HIT IN THE EAST. EXPECT LESS DROP THESE ZONES FOR REST OF NIGHT WITH CLOUDS THICKENING. PREVIOUS DISCUSSION .SHORT TERM...TONIGHT THROUGH FRIDAY. SNOW WITH WEAKENING SYSTEM APPROACHING FROM MINNESOTA IS THE MAIN CHALLENGE. THE SYSTEM IS MOVING INTO HIGH PRESSURE AND DRY AIR WITH LITTLE WARM ADVECTION. IT DOES HAVE SOME DECENT UPPER SUPPORT WHICH WILL COMPENSATE FOR THE LIMITATIONS IT HAS. THERE FORE WILL GO WITH LIKELY IN THE WEST AND A CHANCE OF SNOW IN THE EAST. THERE MIGHT BE AN INCH OF SNOW IN THE WESTERN PART OF THE FORECAST AREA. SOME LEFTOVER FLURRIES EXPECTED FRIDAY. .LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY DRY CONDITIONS WILL PREVAIL FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE REGION. HIGH PRESSURE WILL SLIDE ACROSS WISCONSIN ON SATURDAY...THEN EAST OF THE STATE SATURDAY NIGHT. NEXT CLIPPER SYSTEM MOVES TOWARDS THE AREA SUNDAY. MODELS CONTINUE TO SHOW DIFFERENCES IN HANDLING 850MB TEMPERATURES AND HOW IT WILL AFFECT TEMPERATURES IN THE MONDAY AND TUESDAY TIME FRAME. LIKE YESTERDAY...THINK THE GFS IS TOO COLD AND THE ECWMF TOO WARM DURING THIS TIME FRAME. TOOK A COMPROMISE BETWEEN THE TWO MODELS FOR 850MB TEMPERATURES. CURRENT FORECAST TEMPERATURES SEEM TO BE REASONABLE AT THIS TIME. HIGH PRESSURE WILL SLIDE ACROSS WISCONSIN TUESDAY AND TUESDAY NIGHT. OFFICES TO OUR SOUTH HAVE PRECIPITATION IN THE FORECAST... BUT BASED ON UPPER LEVEL PATTERN WILL LEAVE TUESDAY NIGHT DRY AS SYSTEM WILL BE SLOWER TO ARRIVE. DECENT WARM ADVECTION BEGINS ON WEDNESDAY. STEEP MID LEVEL LAPSE RATES OF 6.5 TO 7.5 C/KM AND WEAK IMPULSES MOVING ACROSS THE AREA WILL KEEP THE CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS IN THE FORECAST WEDNESDAY THROUGH THURSDAY. && .AVIATION... && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ KIECKBUSCH/MG WEATHER.GOV/GREENBAY $$ WEATHER.GOV/GREENBAY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
554 AM EDT FRI MAR 16 2007 AVIATION... COOL AND DRY NORTHEAST FLOW WILL BECOME NORTH DURING THE TAF PERIOD. REMOVED SCT050 FROM SBN TAF GIVEN ACARS SOUNDING AT LANSING...WHICH SHOWED VERY DRY LOW LEVELS...ESPECIALLY ABOVE THE BASE OF THE SUBSIDENCE INVERSION. KEPT VFR CONDITIONS THROUGHOUT THE TAF PERIOD AS THE LOW LEVELS REMAIN VERY DRY. && .SHORT TERM... TODAY AND TONIGHT...THE FORECAST AREA WILL REMAIN BETWEEN RIDGING FROM THE UPPER MIDWEST INTO CANADA AND LOW PRESSURE TRACKING NORTHEAST ALONG THE ATLANTIC COAST. VERY DRY AIR HAD ALREADY SPREAD INTO LOWER MICHIGAN...WITH DEW POINTS FROM 5F TO 15F. NORTHEAST WINDS WILL EVENTUALLY BECOME NORTH...BUT KEEP THE COLD AND DRY FLOW OVER THE AREA. TEMPERATURES WILL REMAIN SEVERAL DEGREES BELOW NORMAL. UNDERCUT MAV MOS HIGHS AND WENT WITH THE COLDER NGM/FWC TEMPERATURES. CLOUD COVER A CHALLENGE AS CLOUDS FROM THE LOW PRESSURE SYSTEM TO THE SOUTHEAST HAVE SPREAD OVER THE AREA...AND LOWER CLOUDS SHOULD SPREAD ALL OF THE WAY WEST INTO NW OHIO. THEREFORE...HAVE HIGHEST CLOUD COVER OVER THIS AREA...BUT GENERALLY PARTLY CLOUDY ELSEWHERE. $$ .LONG TERM... SATURDAY THROUGH THURSDAY. AN UPR LVL TROF WILL CARVE ITSELF OUT ACRS THE ERN GREAT LAKES INTO THE MID ATLANTIC REGION ON SATURDAY. OUR FCST AREA WILL BE ON THE BACK SIDE OF THIS SYSTEM...SO ANY PCPN WILL REMAIN WELL TO THE EAST. HOWEVER...CAA WILL CONTINUE TO STREAM INTO THE REGION IN THE LOW LEVELS. 850 MB TEMPS ON BOTH THE 00Z GFS AND 00Z NAM-WRF ARE FCST TO DROP AROUND -10 C TO -11 C. TAKING A DRY ADIABAT FROM THESE VALUES TO THE SFC YIELDS A HIGH AROUND 36 DEGREES. THUS...WILL UNDERCUT MAV MOS GUIDANCE WHICH SEEMS TOO WARM. WITH 850 MB TEMPS AROUND -11 C AND A NORTHERLY FLOW OFF OF LAKE MICHIGAN...THERE WILL LIKELY BE SOME LAKE INDUCED CLOUDS DOWNWIND OF LAKE MICHIGAN. THERE PROBABLY WILL NOT BE ENOUGH DEEP MOISTURE OVERALL TO GENERATE PCPN. THUS...HAVE REMOVED THE CHC OF FLURRIES FROM THE FORECAST ON SATURDAY. OTHERWISE...PARTLY CLOUDY SKIES ARE EXPECTED WITH TEMPS SOME 10 DEGREES BELOW NORMAL FOR MID MARCH. FOR SATURDAY NIGHT...SFC HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE WEST...ALLOWING SKIES TO CLEAR. WITH CLEAR SKIES AND WINDS BECOMING LIGHT OVERNIGHT...GOOD RADIATIONAL COOLING IS ANTICIPATED. OVERNIGHT LOWS WILL DROP INTO THE UPPER TEENS TO LOWER 20S. FOR SUNDAY INTO MONDAY...A FAST MOVING S/WV WILL DIVE OUT OF THE WRN PROVINCES OF CANADA INTO SRN ONTARIO. A COLD FRONT WILL BE ASSOCIATED WITH THIS SYSTEM. OUT AHEAD OF THIS SYSTEM...MODELS CONTINUE TO SHOW WARM...MOIST ASCENT DEVELOPING SUNDAY NIGHT AND CONTINUING INTO MONDAY. SKIES WILL START OUT PARTLY CLOUDY ON SUNDAY WITH CLOUDS THICKENING FROM WEST TO EAST THROUGHOUT THE DAY. AFTER A VERY COLD START...BELIEVE MAV MOS GUIDANCE IS TOO WARM FOR SUNDAYS HIGHS...SO HAVE CUT BACK ON THESE VALUES. HIGHS WILL RANGE FROM THE UPPER 30S TO THE LOWER 40S. PCPN IS FCST TO BREAK OUT ACRS THE AREA SUNDAY NIGHT. MODEL SOUNDINGS INDICATE THAT THE PCPN MAY START OUT AS RAIN...THEN IT WILL BECOME A RAIN/SNOW MIX OR PERHAPS CHANGE TO SNOW FOR A PERIOD ACRS ROUGHLY THE NE TWO THIRDS OF THE FCST AREA. EVENTUALLY...ENOUGH WARM AIR WILL OVERSPREAD THE ENTIRE REGION FOR THE PCPN TO CHANGE TO ALL RAIN BY SUNRISE MONDAY MORNING. ATTM...WILL KEEP A 40 PERCENT CHC OF RAIN OR RAIN/SNOW MIX FOR SUNDAY NIGHT. ON MONDAY...WAA AHEAD OF THE COLD FRONT WILL ALLOW TEMPS TO RISE INTO THE UPPER 40S TO LOWER 50S. THERE WILL BE A LINGERING CHC FOR RAIN. FOR MONDAY NIGHT INTO TUESDAY...THE AFOREMENTIONED COLD FRONT WILL DIVE SOUTHEAST THROUGH THE AREA. SKIES WILL BECOME PARTLY CLOUDY. SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR TUESDAY. FOR THE REMAINDER OF THE EXTENDED...TUESDAY NIGHT THROUGH THURSDAY...THE UPR LVL PATTERN ACRS THE UNITED STATES WILL FEATURE A DIGGING TROF ACRS THE WEST...WITH A DEVELOPING WARM...MOIST SOUTHWEST FLOW ACRS THE CNTRL UNITED STATES INTO THE WESTERN GREAT LAKES. TEMPERATURES WILL MODERATE THROUGH THE PERIOD. SVRL WX DISTURBANCES ARE FCST TO EJECT FROM THE MAIN TROF TOWARD THE GREAT LAKES REGION DURING THE PERIOD. THESE SYSTEMS WILL KEEP A THREAT FOR RAIN THROUGH THE END OF THE EXTENDED PERIOD. $$ .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM EDT SUNDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...SKIPPER LONG TERM....HICKMAN
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
259 AM MDT FRI MAR 16 2007 .DISCUSSION... WELL ABOVE NORMAL TEMPS EXPECTED AGAIN TODAY WEST OF THE CENTRAL MOUNTAIN CHAIN. 08Z SFC ANALYSIS THIS MORNING SHOWS HIGH PRESSURE BUILDING SOUTH DOWN THE HIGH PLAINS BEHIND A COLD FRONT STRETCHING FROM CENTRAL TEXAS WESTWARD INTO THE UPPER GILA REGION. LOW CLOUDS HAVE DEVELOPED ACROSS MUCH OF THE EASTERN PLAINS. LATEST WATER VAPOR LOOP SHOWS A LARGE UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES. 400-250MB AIRCRAFT WIND DATA SHOWS A 120-140 KNOT JET ALONG THE NORTHEAST PERIPHERY OF THE UPPER RIDGE OVER THE NORTHERN ROCKIES. 00Z MREF/03Z SREF IN VERY GOOD AGREEMENT THAT THE UPPER RIDGE WILL BUILD TO THE EAST OVER NM THROUGH SATURDAY MORNING AS THE UPPER JET OVER THE NORTHERN ROCKIES MOVES EAST INTO THE UPPER MIDWEST. THIS WILL KEEP TEMPS 10-20F ABOVE NORMAL ACROSS THE WESTERN HALF OF THE STATE HOWEVER THINK MID LEVEL INVERSIONS BEHIND THE FRONT WILL LIMIT MIXING IN THESE AREAS SO NOT EXPECTING MORE RECORD TEMPS. THE EAST WILL BE MUCH COOLER THAN THURSDAY AS MORNING LOW CLOUDS AND INVERSION INHIBITS STRONG WARMING. HOWEVER LEE TROUGHING BY LATE AFTERNOON WILL STILL BRING TEMPS UP TO SEASONAL NORMALS. AS THE RIDGE FLATTENS SATURDAY AND SUNDAY EXPECT WELL ABOVE NORMAL TEMPS TO CONTINUE STATEWIDE. LEE TROUGHING AND DOWNSLOPE WINDS WILL REBOUND TEMPS INTO THE 80S ONCE AGAIN IN THE EAST WITH NEAR RECORD WARMTH AGAIN TO THE WEST. MODELS THEN INDICATE INCREASING CHANCES FOR PRECIP LATE MONDAY OVER THE NE PLAINS AS A COLD FRONT ATTEMPTS TO SURGE SOUTH FROM EASTERN COLORADO. MEANWHILE WEAK PIECES OF ENERGY WILL MOVE OVER THE STATE AHEAD OF A MORE SUBSTANTIAL UPPER LEVEL DISTURBANCE DEVELOPING OVER SOUTHERN CALIFORNIA TUESDAY. HIGH AND MID LEVEL CLOUDS WILL INCREASE FROM THE WEST WITH A CHANCE FOR SHOWERS STATEWIDE BY WEDNESDAY. 700MB TEMPS BETWEEN -2 AND -4C WILL ALLOW FOR SNOW SHOWERS IN THE HIGHER TERRAIN TUESDAY NIGHT INTO WEDNESDAY. ANOTHER SYSTEM LOOMS QUICKLY ON ITS HEELS FOR THURSDAY HOWEVER THIS ONE LOOKS TO HEAD MORE TO THE SOUTH OVER OLD MEXICO AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 72 33 74 37 / 0 0 0 0 GALLUP.......................... 74 28 77 32 / 0 0 0 0 GRANTS.......................... 75 29 78 33 / 0 0 0 0 GLENWOOD........................ 80 45 82 43 / 0 0 0 0 CHAMA........................... 62 23 65 26 / 0 0 0 0 LOS ALAMOS...................... 65 36 71 37 / 0 0 0 0 RED RIVER....................... 56 20 60 25 / 0 0 0 0 TAOS............................ 66 24 69 29 / 0 0 0 0 SANTA FE........................ 68 37 73 37 / 0 0 0 0 SANTA FE AIRPORT................ 70 36 75 38 / 0 0 0 0 ESPANOLA........................ 74 34 77 36 / 0 0 0 0 ALBUQUERQUE HEIGHTS............. 74 46 78 46 / 0 0 0 0 ALBUQUERQUE VALLEY.............. 78 45 81 44 / 0 0 0 0 ALBUQUERQUE FOOTHILLS........... 71 45 77 45 / 0 0 0 0 ALBUQUERQUE WEST MESA........... 75 46 79 46 / 0 0 0 0 SOCORRO......................... 78 45 82 47 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 65 48 72 44 / 0 0 0 0 MORIARTY/ESTANCIA............... 68 34 76 36 / 0 0 0 0 CARRIZOZO....................... 74 43 79 46 / 0 0 0 0 RUIDOSO......................... 65 45 72 46 / 0 0 0 0 RATON........................... 63 32 75 32 / 0 0 0 0 LAS VEGAS....................... 64 36 73 39 / 0 0 0 0 ROY............................. 62 41 74 42 / 0 0 0 0 CLAYTON......................... 63 40 77 43 / 0 0 0 0 SANTA ROSA...................... 68 38 82 43 / 5 0 0 0 TUCUMCARI....................... 67 42 83 46 / 0 0 0 0 FORT SUMNER..................... 68 41 83 44 / 0 0 0 0 CLOVIS.......................... 66 42 81 44 / 0 0 0 0 PORTALES........................ 67 41 82 43 / 0 0 0 0 ROSWELL......................... 70 44 87 48 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ GUYER
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
415 AM PDT FRI MAR 16 2007 .SYNOPSIS... A SHALLOW MARINE LAYER AND WEAK ONSHORE FLOW WILL BRING AREAS OF DENSE FOG TO INLAND COASTAL AREAS EARLY THIS MORNING. OTHERWISE... SLIGHT STRENGTHENING OF HIGH PRESSURE ALOFT WILL BRING WARMER TEMPERATURES TO INLAND AREAS TODAY. FOR THE WEEKEND THROUGH EARLY NEXT WEEK...HIGH PRESSURE ALOFT WILL WEAKEN AND ONSHORE FLOW WILL STRENGTHEN. THIS WILL BRING A COOLING TREND AND INCREASING MARINE LAYER WITH GUSTY AFTERNOON AND EVENING WINDS IN THE MOUNTAINS AND DESERTS AT TIMES. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TODAY THROUGH SUNDAY)... ACARS SOUNDINGS SHOW A STRONG MARINE INVERSION WITH THE BASE NEAR 1000 FEET...SUFFICIENT FOR STRATUS TO EXTEND INLAND TO THE LOWER COASTAL VALLEYS. COMBINED WITH WEAK ONSHORE FLOW...THERE WILL BE AREAS OF DENSE FOG EARLY THIS MORNING OVER INLAND COASTAL SECTIONS INLAND TO THE LOWER COASTAL VALLEYS. WITH WEAKENING OF ONSHORE GRADIENTS TODAY AND SLIGHT BUILDING OF HIGH PRESSURE ALOFT TODAY... THERE SHOULD BE SOME WARMING FOR INLAND AREAS TODAY...GREATEST IN THE VALLEYS...WHERE HIGHEST TEMPERATURES IN THE INLAND VALLEYS WILL CLIMB BACK ABOVE 90. FOR THE WEEKEND...HIGH PRESSURE ALOFT WILL BEGIN TO WEAKEN AND ONSHORE FLOW STRENGHTEN. THIS WILL BRING A COOLING TREND AND A DEEPENING MARINE LAYER. && .LONG TERM (MONDAY THROUGH THURSDAY)... THE DEEPENING TREND FOR THE MARINE LAYER WILL CONTINUE FOR MONDAY AND TUESDAY WITH STRATUS EXTENDING ONTO THE COASTAL SLOPES BY TUESDAY MORNING. GFS/DGEX/ECMWF MOVE A TROUGH THROUGH SOUTHERN CALIFORNIA THAT AT ITS CURRENT FORECAST INTENSITY WOULD BE SUFFICIENTLY STRONG TO BRING SHOWERS TO SOUTHWEST CALIFORNIA. MODELS BRING A WEAKER...SECONDARY SHORTWAVE THROUGH IN NORTHWEST FLOW LATE WEDNESDAY AND EARLY THURSDAY. PRECIPITATION PROSPECTS WOULD BE LESS FOR THIS SYSTEM...BUT IT WOULD REINFORCE TEMPERATURES BELOW SEASONAL AVERAGES AND BRING GUSTY WINDS TO THE MOUNTAINS AND DESERTS. HIGH PRESSURE SHOULD REBUILD FOR THE NEXT WEEKEND BRINGING FAIR AND WARMER WEATHER. && .AVIATION... 151115Z...MARINE LAYER ABOUT 800 FT WITH MVFR AND LOCAL IFR NEAR THE COAST. EXPECT STRATUS TO CLEAR ABOUT 17Z. EXPECT ABOUT THE SAME TONIGHT. BASES ABOUT 500-700 FT MSL. EAST TO SOUTHEAST WINDS 5-10 KT BELOW 10K FT THROUGH TONIGHT...BECOMING LIGHT WEST SATURDAY MORNING AND AFTERNOON. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...DENSE FOG ADVISORY UNTIL 8 AM PDT THIS MORNING FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO COUNTY VALLEYS. PZ...NONE. && $$ PUBLIC...MARTIN AVIATION/MARINE...WHITLOW NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1120 AM EDT FRI MAR 16 2007 .UPDATE... SNOW SHOWERS HAVE DIMINISHED SIGNIFICANTLY OVER THE LAST FEW HOURS AS LARGE SCALE LIFT FM SHORTWAVE/2D-FRONTOGENESIS HAS SUBSIDED. 10Z-12Z TAMDAR SOUNDINGS FM CENTRAL WI SHOWED MOIST PROFILE TO H6 WHILE 12Z KINL/KGRB SOUNDINGS HAD MOISTURE BLO H9 BUT WERE DRY ABOVE THAT SHALLOW MOIST LAYER. THE MOISTURE IN CENTRAL WISCONSIN IS THE REMNANT OF THE SHORTWAVE/FRONTOGENESIS THAT MOVED INTO THE AREA LAST NIGHT AND PRODUCED LGT SNOW OVR WEST HALF OF CWA. LATEST RUC/NAM INDICATE NARROW SWATH OF THIS DEEPER MOISTURE WILL MAINLY AFFECT EAST CWA THIS AFTN WHILE CONTINUING TO DIMINISH. SCT LK EFFECT CLOUDS ARE ALSO PRESENT INTO NCNTRL UPR MI AS H85 TEMPS MAINTAIN NEAR -13C AND LIGHT NE WINDS FLOW OVR LK SUPERIOR. WEAK LK EFFECT REGIME MAY CONTINUE TO PRODUCE SOME FLURRIES THIS AFTN OVR NCNTRL UPR MI. ALSO...HAVE AN OUTSIDE CHANCE AT DEVELOPMENT OF INSTABILITY SNOW SHOWERS AS THERMAL TROUGH AT H7-H5 (H7 TEMPS -20/H5 TEMPS -40C) ROLL ACROSS. TROUBLE IS THAT MOISTURE WITHIN THIS LAYER WITH STEEPEST LAPSE RATES IS DIMINISHING AND THERE IS NO LARGE SCALE LIFT TO PROVIDE A GOOD TRIGGER. AT A MINIMUM...THE STEEP LAPSE RATES SHOULD CONTINUE TO HELP REINFORCE CUMULUS CLOUDS OVR LAND. LATEST SATELLITE AND LOOK OUT WINDOW SHOWS THIS INDEED IS BEGINNING TO OCCUR. TEMPS AND WINDS LOOKED FINE. NO CHANGES NEEDED. && .PREV DISCUSSION (405 AM EDT)... 00Z RAOBS/LATEST WV IMAGERY SHOWS TROFFING OVER THE GRT LKS DOWNWIND OF RDG ALG THE W COAST. FAIRLY HEALTHY EMBEDDED SHRTWV MOVING INTO NW WI WITHIN THE TROF AND CAUSING SOME -SN OVER THE W HALF EARLY THIS MRNG AS SFC LO TRACKS ACRS SRN WI. ALTHOUGH AIRMASS FARTHER E ACRS UPR MI IS QUITE DRY/STABLE PER THE 00Z GRB/APX RAOBS AND THERE IS ONLY WEAK ISENTROPIC LIFT ON THE 275-280K SFCS (H85-7) TO SATURATE THE DRY AIRMASS SHOWN ON THE 00Z RAOBS...AREA OF SN HAS PUSHED E INTO THE CNTRL ZNS AS OF EARLY THIS MRNG WITH AREA OF H5-7 FGEN. HI PRES RDG TO THE NW OF SHRTWV/CLD MASS IS MOVING TOWARD NW MN... AND SKIES ARE MOCLR IN THIS AREA AS 00Z YPL/ BIS SDNGS RATHER DRY (PWAT 0.07 INCH/0.13 INCH). ANOTHER WEAKER SHRTWV APRNT OVER SASKATCHEWAN DIGGING SE. AN AREA OF ASSOCIATED MID/HI CLD HAS REACHED LK WINNIPEG AS 00Z YQD SDNG SHOWS A RELATIVELY MOIST AIRMASS ABV DRY AIR BLO H85. SOME -SN IS FALLING OVER NCNTRL SASKATCHEWAN WHERE THE LLVLS APRNTLY HAVE MOISTENED. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND SN CHCS ASSOCIATED WITH SHRTWVS NOTED ABV MOVING THRU TROF OVER THE GRT LKS. FOR TDAY...LATEST RUC/NAM SHOW SHRTWV TENDING TO WEAKEN AS IT MOVES TO THE E LATE TNGT INTO EARLY FRI...WITH ANY ISENTROPIC LIFT ON THE 275-280K SFCS ENDING AS THE FLOW BECOMES LGT N AT THOSE LVLS AND DRIER AIR WORKS BACK IN. THE RESULT IS SLOW DRYING SHOWN ON THE 00Z NAM SDNGS...AND MODEL QPF AFT 12Z IS ZERO AS SFC RDG TO THE NW BLDS IN DURING THE AFTN. CONSIDERING DRY AIRMASS IN PLACE TO THE E AND LARGER SCALE PLACEMENT OF CWA IN SUBSIDING LEFT ENTRANCE OF UPR JET AXIS FM LK HURON INTO SRN QUEBEC...WL CARRY ONLY SCT -SHSN/FLURRIES TO APPROXIMATELY P53-ISQ THIS MRNG BEFORE MID LVL FGEN WEAKENS. SINCE NAM/GFS FCST SDNGS SHOW SOME RATHER STEEP LAPSE RATES BLO DVLPG SUBSIDENCE INVRN ARND H75 IN THE AFTN...SOME CONCERN ABOUT INSTABILITY -SHSN DVLPG FARTHER W. HOWEVER...NAM/GFS FCST LLVL DWPTS LOOK TOO HI CONSIDERING OBS OVER NW MN/ADJOINING ONTARIO CLOSE TO INCOMING RDG AXIS. GFS ALSO SHOWS A MUCH LOWER SUBSIDENCE INVRN ARND H85. SO ALTHOUGH THERE MAY BE SOME SC...WL GO DRY PER LO ETA/NGM/GFS MOS POPS EXCEPT FOR SCT FLURRIES OVER THE INTERIOR WHERE SFC HTG MAY PROMOTE GREATEST LLVL DESTABILIZATION. FOR TNGT...SHRTWV NOW OVER SASKATCHEWAN FCST TO SHEAR SEWD INTO THE UPR LKS. GFS/NAM BOTH SHOW DEEPER MSTR REMAINING TO THE N IN ONTARIO WITH FA STILL DOMINATED BY RDG AXIS/LLVL DRIER AIR UNDER GENERAL UPR CNVGC. ALTHOUGH H85 FCST TEMPS ARND -13C WOULD ALLOW SOME LES... LLVL ACYC FLOW/LGT WINDS THAT WOULD DISRUPT ANY BANDING/DRY LLVL AIR UPSTREAM WL GREATLY LIMIT ANY ACTIVITY. CONCERNED SOME VORTICES MIGHT FORM OVER LK SUP WITH LOSS OF DIURNAL HTG...AND RUC13 HINTS AT A WEAK ONE DVLPG OVER SCNTRL LK SUP. OPTED TO MAINTAIN SCHC POPS NEAR LK SUP DURING THE NGT...A BIT HIER OVER THE NCNTRL FM MQT-P53 WHERE H85 FLOW IS A BIT MORE CONFLUENT. CONSIDERING THE LGT WINDS UNDER THE RDG AND EXPECTED CLRG OVER THE INTERIOR...WL TEND TOWARD THE LOWER GFS MOS GUIDANCE FOR FCST LO TEMPS TNGT AWAY FM LK MODERATION. WITH DRY HI PRES RDG REMAINING IN CONTROL UNDER UPR CNVGC ON SAT... EXPECT QUIET DAY. BOTH NAM/GFS FCST SFC DWPTS RISING INTO THE 20S SEEM UNRSNBL...PREFER THE MOS NUMBERS 10 TO AS MUCH AS 15F LOWER THAN FCST BY EXPLICIT MODEL GUIDANCE...ESPECIALLY WITH MIXING TO SUBSIDENCE INVRN AT H85 AS SHOWN ON GFS FCST SDNGS UNDER INCRSG SUN ANGLE. ANY LK EFFECT SN NR LK SUP SHOULD DIMINISH WITH INSOLATION AND SHIFT TO THE ERN ZNS DURING THE AFTN WITH BACKING H85 FLOW TO MORE NW. MIXING TO H85 ON GFS FCST SDNGS SUPPORTS GOING FCST HI TEMPS...SO FEW CHGS MADE. ALTHOUGH THERE MAY BE AN INCRS IN MID/HI CLD LATE ON SAT NGT OVER THE W HALF WITH SOME ISENTROPIC LIFT DVLPG IN ADVANCE OF NEXT CLIPPER LO FCST TO PUSH INTO THE NRN PLAINS BY 12Z SUN...EXPECT A DRY NGT. THE ONLY EXCEPTION WL BE NR LK SUP E OF P53 WHERE CONTD NW FLOW AND H85 TEMPS UNDER -13C WL CAUSE SOME LES. WENT TOWARD LO END OF MOS GUIDANCE OVER THE INTERIOR SCNTRL...WHERE CLD/LK INFLUENCE WL BE MINIMAL. THE LES WL END ON SUN MRNG AS SFC-H85 RDG AXIS PASSES OVHD BY 18Z SUN. OTRW...GOING CHC POPS SPRDG INTO THE W HALF ON SUN AFTN STILL APPEARS ON TRACK WITH SFC LO MOVING INTO NW ONTARIO BY 00Z MON AND FAIRLY SHARP ISENTROPIC LIFT DVLPG ON THE 290K SFC. COORDINATED WITH APX/GRB. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...JLA PREV DISCUSSION...KC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
634 AM CDT FRI MAR 16 2007 ...UPDATED AVIATION DISCUSSION... .DISCUSSION... NORTHWEST FLOW ALOFT PERSISTS ACROSS THE REGION EARLY THIS MORNING A SURFACE HIGH PRESSURE DRIFTS SOUTHEAST INTO THE FORECAST AREA. TODAY LOOKS TO BE DRY...THEREFORE THE MAIN CONCERN IN THE VERY SHORT TERM WILL BE TEMPERATURES. LOOKING AT THE IR SATELLITE THIS MORNING...SOME LOW STRATUS WAS PROGRESSING SOUTHWARD ACROSS IOWA AND SHOWS NO SIGNS OF DISSIPATING. MODELS DO NOT SEEM TO HAVE A GREAT HANDLE ON THIS MOISTURE. THE NAM HINTS AT THIS CLOUD COVER BUT KEEPS IT NORTH AND EAST OF THE AREA. WITHOUT THICK CLOUD COVER...TEMPERATURES ACROSS THE AREA WOULD BE SIMILAR BUT A COUPLE OF DEGREES COOLER THAN YESTERDAY. FOR NOW BANKING ON WESTERN AREAS NOT SEEING AS MUCH CLOUD COVER AND WENT WITH HIGHS GENERALLY IN THE MIDDLE 50S. WITH MORE CLOUDS EXPECTED NORTH AND EAST WENT WITH MIDDLE TO UPPER 40S TOWARD THE KIRKSVILLE AREA. THESE TEMPS MAY NEED TO BE TWEAKED FURTHER BY THE SHORT TERM DESK TODAY IF CLOUD TRENDS CHANGE. FOCUS THEN TURNS TO PRECIPITATION CHANCES LATE TONIGHT INTO SATURDAY. BOTH THE NAM AND GFS SHOW SOME FAIRLY STRONG ISENTROPIC LIFT IN THE 280-290K LAYER DEVELOPING TOWARD DAWN AND QUICKLY SPREADING ACROSS THE FORECAST AREA SATURDAY MORNING. INCREASED POPS BUT KEPT THEM IN THE LOW-END CHANCE RANGE. THE GFS IS WETTER THAN THE NAM...AS IT PRODUCES A BAND OF A TENTH INCH OF LIQUID. HOWEVER...LOOKING AT SOUNDINGS THERE IS A DECENT AMOUNT OF LOW-LEVEL DRY AIR TO OVERCOME. IN ADDITION...THE 21Z RUN OF THE SREF ONLY SHOWED A 20 TO 30 PERCENT CHANCE OF VERY LIGHT PRECIPITATION. KEPT THE PREVIOUS RAIN/SNOW WORDING AS TEMPERATURES WILL BE HOVERING AROUND THE FREEZING MARK AND SOME EVAPORATIVE COOLING IS LIKELY. WITH THE QUICK MOVEMENT OF FORCING AND LACK OF DEEP MOISTURE...NOT EXPECTING ANY SIGNIFICANT ACCUMULATIONS OF WINTRY PRECIP WITH THIS SYSTEM. AFTER THIS SYSTEM PASSES DRY CONDITIONS SHOULD PERSIST AT LEAST THROUGH THE DAY ON SUNDAY BEFORE ANOTHER FRONT APPROACHES THE AREA SUNDAY NIGHT. THIS FRONT WILL LIKELY STALL OUT SOMEWHERE NEAR THE MISSOURI-ARKANSAS BORDER...BEFORE RETURNING NORTHWARD AS A WARM FRONT BY WEDNESDAY. WEAK DISTURBANCES IN THE SOUTHERN STREAM INTERACTING WITH THIS FRONT MAY PRODUCE SEVERAL ROUNDS OF SHOWERS AND POSSIBLY THUNDERSTORMS ACROSS THE AREA. FOR NOW KEPT ONLY CHANCE POPS IN THE GRIDS FOR THE FIRST HALF OF THE UPCOMING WORK WEEK AS TIMING THE DISTURBANCES WILL BE A CHALLENGE. DID NOT CHANGE POPS TO THE END OF THE EXTENDED (WEDNESDAY INTO THURSDAY)...BUT THE GFS IS SHOWING AN ACTIVE PERIOD AS A STRONGER UPPER WAVE PUSHES INTO THE PLAINS. MANY TIMES THE GFS BRINGS THE ENERGY INTO THE PLAINS TOO QUICKLY. AT SOME POINT...POPS WILL LIKELY NEED TO BE RAISED DURING THE MID TO LATE WEEK PERIOD. IN ADDITION...WE`LL HAVE TO KEEP WATCH ON SEVERE WEATHER POTENTIAL AS THERE WILL BE ABUNDANT MOISTURE IN PLACE AS THE SYSTEM PUSHES THROUGH THE REGION. SAW && .AVIATION... TIME TO THROW OUT THE MODELS. NOT A SINGLE PIECE OF SHORT TERM GUIDANCE HAS RESOLVED THE LARGE SWATH STRATUS THAT CONTINUES TO SURGE SOUTHWARD FROM IOWA/ERN NEBRASKA INTO NORTHERN MISSOURI. 11-3.9 MICRON SATELLITE IMAGERY SHOWS THE EXTENT OF THE STRATUS IS QUITE IMPRESSIVE WHILE A RECENT ACARS-EQUIPPED AIRCRAFT DEPARTURE FROM OMAHA SHOWS THAT THIS CLOUD DECK IS PROBABLY LESS THAN 100 FEET THICK WITH A SINGLE LAYER OF SATURATION TRAPPED BENEATH A VERY STEEP AND DRY INVERSION. THUS IT SHOULD BURN OFF RELATIVELY QUICKLY THIS MORNING BUT NOT BEFORE THE TERMINALS EXPERIENCE A PERIOD OF MVFR TO LOCALLY IFR CEILINGS. WILL FIGURE FOR CEILINGS TO SCATTER OUT BEFORE NOONTIME...WITH VFR CONDITIONS PREVAILING BEYOND 18Z. NORTHERLY WINDS WILL CONTINUE TO DIMINISH...AND SHIFT INTO THE EAST WITH THE PASSAGE OF HIGH PRESSURE THIS EVENING. BOOKBINDER && EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1024 AM MDT FRI MAR 16 2007 .UPDATE...MADE THE SE ZONES A LITTLE MORE PESSIMISTIC AS TO THE CLOUD COVER. THEREFORE DECREASED TEMPS A FEW DEGREES AS WELL. MAIN CHANGES FROM ROSWELL TO CLOVIS. CHJ && .PREV DISCUSSION...259 AM MDT FRI MAR 16 2007... WELL ABOVE NORMAL TEMPS EXPECTED AGAIN TODAY WEST OF THE CENTRAL MOUNTAIN CHAIN. 08Z SFC ANALYSIS THIS MORNING SHOWS HIGH PRESSURE BUILDING SOUTH DOWN THE HIGH PLAINS BEHIND A COLD FRONT STRETCHING FROM CENTRAL TEXAS WESTWARD INTO THE UPPER GILA REGION. LOW CLOUDS HAVE DEVELOPED ACROSS MUCH OF THE EASTERN PLAINS. LATEST WATER VAPOR LOOP SHOWS A LARGE UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES. 400-250MB AIRCRAFT WIND DATA SHOWS A 120-140 KNOT JET ALONG THE NORTHEAST PERIPHERY OF THE UPPER RIDGE OVER THE NORTHERN ROCKIES. 00Z MREF/03Z SREF IN VERY GOOD AGREEMENT THAT THE UPPER RIDGE WILL BUILD TO THE EAST OVER NM THROUGH SATURDAY MORNING AS THE UPPER JET OVER THE NORTHERN ROCKIES MOVES EAST INTO THE UPPER MIDWEST. THIS WILL KEEP TEMPS 10-20F ABOVE NORMAL ACROSS THE WESTERN HALF OF THE STATE HOWEVER THINK MID LEVEL INVERSIONS BEHIND THE FRONT WILL LIMIT MIXING IN THESE AREAS SO NOT EXPECTING MORE RECORD TEMPS. THE EAST WILL BE MUCH COOLER THAN THURSDAY AS MORNING LOW CLOUDS AND INVERSION INHIBITS STRONG WARMING. HOWEVER LEE TROUGHING BY LATE AFTERNOON WILL STILL BRING TEMPS UP TO SEASONAL NORMALS. AS THE RIDGE FLATTENS SATURDAY AND SUNDAY EXPECT WELL ABOVE NORMAL TEMPS TO CONTINUE STATEWIDE. LEE TROUGHING AND DOWNSLOPE WINDS WILL REBOUND TEMPS INTO THE 80S ONCE AGAIN IN THE EAST WITH NEAR RECORD WARMTH AGAIN TO THE WEST. MODELS THEN INDICATE INCREASING CHANCES FOR PRECIP LATE MONDAY OVER THE NE PLAINS AS A COLD FRONT ATTEMPTS TO SURGE SOUTH FROM EASTERN COLORADO. MEANWHILE WEAK PIECES OF ENERGY WILL MOVE OVER THE STATE AHEAD OF A MORE SUBSTANTIAL UPPER LEVEL DISTURBANCE DEVELOPING OVER SOUTHERN CALIFORNIA TUESDAY. HIGH AND MID LEVEL CLOUDS WILL INCREASE FROM THE WEST WITH A CHANCE FOR SHOWERS STATEWIDE BY WEDNESDAY. 700MB TEMPS BETWEEN -2 AND -4C WILL ALLOW FOR SNOW SHOWERS IN THE HIGHER TERRAIN TUESDAY NIGHT INTO WEDNESDAY. ANOTHER SYSTEM LOOMS QUICKLY ON ITS HEELS FOR THURSDAY HOWEVER THIS ONE LOOKS TO HEAD MORE TO THE SOUTH OVER OLD MEXICO AT THIS TIME. && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 40
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1109 AM CDT FRI MAR 16 2007 .UPDATE... TEMPERATURES A REAL HEADACHE TODAY. GOT LOW CLOUDS FROM NE SD INTO WCTNRL MN...WITH A MOVEMENT NORTH INDICATED IN THE PAST 1-2 HOURS TOWARD FARGO. GOT 4-7 INCHES OF FRESH SNOW IN NE ND/FAR NW MN WITH SOLAR...THEN GOT SUN WITH OLD SNOW ON THE GROUND IN AREAS WEST OF FARGO TO LIBSON AND VALLEY CITY. ATTM WILL GO WITH THE PREV FCST TEMPS FOR THE MOST PART...THOUGH DID LOWER A BIT IN WCNTRL MN DUE TO EXTENSIVE CLOUD COVER. WILL KEEP MID 20S IDEA IN THE DVL-GFK- TVF AREA...AS STILL GOT MANY HOURS OF WARMING LEFT AS MAX TEMPS NOT TIL 4-5 PM. AS FOR THE LOW CLOUDS....TAMDAR SOUNDING AT 15Z IN NORTHEAST ND (ABR-MSP FLIGHT) SHOW LOW LEVEL MOISTURE IS VERY SHALLOW AND BELOW THE FLIGHT LEVEL SOUNDING. RATHER DRY ABOVE IT WITH MINIMAL HIGH CLOUDS SO SOME THOUGHTS THAT IT WILL BREAK UP AS THE DAY WEARS ON EVEN THOUGH IT IS ADVECTING NORTHWARD. TAMDAR SOUNDINGS FROM AREAS SOUTH OF BEMIDJI SHOW GREATER DEPT OF MOISTURE UP TO AROUND 925 MB AND THIS AREA AROUND BJI-PKD-DTL-FFM EASTWARD MAY HOLD ON THRU THE AFTN. SOME FLURRIES EARLIER IN THE LOW CLOUD AREA...BUT THEY SEEMED TO BE GONE NOW. && .PREV DISCUSSION... /ISSUED 327 AM CDT FRI MAR 16 2007/ SHORT TERM... MAIN FORECAST CHALLENGES FOR THE FRI-MON TIME PERIOD ARE TEMPS AND PCPN CHANCES STARTING SAT AFTERNOON. MODELS IN PRETTY GOOD AGREEMENT ON THERMAL FIELDS/QPF...BUT MODEL MOS IS NOT GOING TO HANDLE THE NEW SNOW FIELD VERY WELL. WILL LEAN TOWARD THE GFS FOR THIS FORECAST. TODAY...LOW CLOUD DECK STILL HOLDING TOUGH EAST OF A KBWP-KDTL- KBJI LINE. SATELLITE LOOP SHOWS THE BACK EDGE OF THESE CLOUDS SLOWING DOWN...SO NOT SURE IF THEY WILL MAKE IT OUT OF THE FA BY SUNRISE. SFC DEW POINTS ALSO A LOT HIGHER UNDER THESE CLOUDS... SO EVEN IF THEY DO CLEAR OUT...THERE COULD BE SOME FOG YET THIS MORNING. OTHERWISE...WITH WEAK SFC HIGH OVER NORTHEAST ND...WINDS ARE VERY LIGHT AND CLOUDS ARE SCANT. FRESH SNOW ALONG THE HIGHWAY 2 CORRIDOR ALSO QUITE EVIDENT IN THE CURRENT TEMPS. SEEING A HIGH VARIATION IN LOWS...WITH FOREST RIVER AT -18F. THIS LIKELY A BIT ON THE EXTREME END (DOUBTFUL OF THE ACCURACY OF THIS)...BUT THERE ARE OTHER SITES IN THE -8F TO -13F RANGE. BIG QUESTION TODAY IS HOW MUCH TEMP RECOVERY WILL TAKE PLACE OVER THE NEW SNOWPACK. VERY WEAK SFC FLOW WILL CONTINUE THROUGH THE DAY...GIVING NEARLY NIL MIXING. SOME HIGH LEVEL CLOUDS BACK OVER EASTERN MT ARE MOVING THIS WAY. AT MOST...THESE MAY GIVE SOME FILTERED SUN FOR THE KDVL REGION BY LATE AFTERNOON. OVERALL...LOTS OF SUN WILL QUICKLY HELP TO MELT OFF THE SLIPPERY ROADS. HOWEVER...DEEP ENOUGH SNOWPACK WILL LIMIT THE TEMP RISE. CUT BACK HIGHS ALONG THE HIGHWAY 2 CORRIDOR...ESPECIALLY FROM KFSE WEST TO KDVL/CANDO. TONIGHT/SAT...WEAK WARM ADVECTION CONTINUES TONIGHT WITH PRETTY LIGHT SFC WINDS. THE MID/HIGH LEVEL CLOUDS WILL CONTINUE TO SPILL TO THE EAST BUT WILL TAKE THE LONGEST TO REACH THE EASTERN FA. WITH THE MELTING SNOW EXPECTED TODAY AND THE LIGHT WINDS/LEAST AMOUNT OF CLOUDS IN THE NORTHEAST FA...THERE MAY BE SOME FOG. THINK THE CLOUDS MOVING INTO THE WESTERN FA WILL KEEP FOG FROM FORMING...BUT IF THEY ARE DELAYED FROM THE CURRENT FORECAST...FOG COULD DEVELOP FURTHER WEST TOO. WILL LET DAY SHIFT DETERMINE IF THIS IS POSSIBLE. KEPT COOLER MINS TONIGHT ALONG THE HIGHWAY 2 CORRIDOR EAST OF KGFK. SAT LOOKS LIKE A CLOUDY DAY WITH WEAK WARM ADVECTION CONTINUING. ONCE AGAIN LOWERED HIGHS OVER THE FRESH SNOW. WITH NO SUN IT WILL HARDER TO WARM...ESPECIALLY WITH SOUTHEAST WINDS. KEPT LOW PCPN CHANCES IN THE WESTERN FA SAT AFTERNOON. PCPN TYPE STILL A QUESTION IN THE WEST. SUN/MON...MODELS CONTINUE TO SHOW 850MB TEMPS RISING SAT NIGHT... WITH 850MB TEMPS RISING ABOVE ZERO IN THE SOUTHWEST FA BY MORNING. INCREASED PCPN CHANCES SAT NIGHT...ESPECIALLY IN THE VALLEY... ALTHOUGH AMOUNTS DO NOT LOOK VERY ROBUST. PCPN SLIDES EAST DURING THE DAY SUNDAY. LOWERED TEMPS SUNDAY TOO...AS WIND FLOW/MIXING LOOKS WEAK DUE TO THE SOUTHERLY WIND TRAJECTORY. COLD FRONT DROPS DOWN THRU THE FA ON SUN NIGHT. LOOKS DRY FOR THE MOST PART... ALTHOUGH A DECENT VORTICITY MAXIMUM DOES BRUSH THE NORTH/NE FA. KEPT SOME LOW PCPN CHANCES IN THESE AREAS BECAUSE OF THIS. KEPT THE TREND OF LOWERING TEMPS INTO MON AS WELL. LONG TERM... NO CHANGES MADE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PDT FRI MAR 16 2007 .SYNOPSIS... A SHALLOW MARINE LAYER WILL CAUSE AREAS OF COASTAL LOW CLOUDS AND DENSE FOG TONIGHT AND SATURDAY MORNING...EXTENDING LOCALLY INLAND. THERE WILL BE A COOLING TREND WITH AN INCREASING MARINE LAYER THIS WEEKEND AS HIGH PRESSURE WEAKENS AND ONSHORE FLOW INCREASES. WEAK UPPER LEVEL LOW PRESSURE WILL BRING A SLIGHT CHANCE OF LIGHT SHOWERS TUESDAY. LESS CLOUDINESS AND WARMER TOWARD THE END OF NEXT WEEK AS HIGH PRESSURE BUILDS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TONIGHT-MON)... LOW CLOUDS AND DENSE FOG WERE INTO THE COASTAL AREAS AND WRN SAN DIEGO INLAND VALLEYS EARLIER THIS MORNING THEN CLEARED TO THE IMMEDIATE COAST BY LATE MORNING. A FAIRLY SOLID DECK OF STRATUS REMAINS ALONG THE COAST AND OFFSHORE. OTHERWISE...MOSTLY CLEAR. EARLY AFTERNOON ACARS SOUNDINGS INDICATED A STRONG INVERSION BASED BELOW 1000 FT. WEAK OFFSHORE GRADIENTS FROM THE N WITH ABOUT -4 MB SAN-TPH AND ONSHORE TO THE E WITH ABOUT 3 MB SAN-IPL. THE HIGH ALOFT WILL GRADUALLY WEAKEN SAT AND SUN AND A SHORT WAVE TROUGH WILL MOVE THROUGH SUN NIGHT FOLLOWED BY A SHORT WAVE RIDGE MON. THE NET RESULT WILL BE A COOLING TREND...ESPECIALLY INLAND..AND A DEEPENING MARINE LAYER. LOW CLOUDS AND FOG SHOULD REACH FARTHER INLAND SUN MORNING AND INTO THE LOWER COASTAL MOUNTAIN SLOPES BY MON MORNING. HOWEVER...THE MARINE LAYER WILL STILL BE SHALLOW TONIGHT AND SAT MORNING WITH DENSE FOG LIKELY ON THE HIGHER COASTAL TERRAIN AND IN THE WRN INLAND VALLEYS. BREEZY IN THE MOUNTAINS AND DESERTS MON AFTERNOON AND EVENING. && .LONG TERM (TUE-FRI)... AN UPPER TROUGH WILL BRING MORE COOLING TUE WITH A SLIGHT CHANCE OF LIGHT SHOWERS. PARTLY CLOUDY SKIES IN DRIER COOL NW FLOW WED. LOCALLY WINDY TUE AFTERNOON AND NIGHT...MAINLY IN THE MOUNTAINS AND DESERTS. HIGH PRESSURE WILL BRING FAIR WEATHER WITH SOME MARINE LAYER CLOUDS AND WARMING TOWARD THE END OF NEXT WEEK. && .AVIATION... 151930Z...MARINE LAYER REMAINS ABOUT 1000 FEET DEEP BASED ON ACARS SOUNDINGS. STRATUS/FOG HAS PULLED BACK TO THE SHORELINE BUT EXPECT IT TO BEGIN TO PUSH BACK INLAND DURING THE EVENING HOURS WITH COASTAL AND MESA AIRPORTS BECOMING IFR OR LOWER WITH BROKEN TO OVERCAST CONDITIONS DURING THIS PERIOD. BASES SHOULD BE AROUND 500 TO 800 FEET MSL WITH TOPS AROUND 1200 FEET. STRATUS/FOG SHOULD PULL BACK TO THE COAST BY 18Z ON SATURDAY. ABOVE THE MARINE LAYER...VFR CONDITIONS SHOULD CONTINUE THROUGH SATURDAY WITH A MOSTLY CLEAR SKY AND UNRESTRICTED VISIBILITIES. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...DVA AVIATION...HORTON
AREA FORECAST DISCUSSION
NWS MIAMI FL
249 PM EDT FRI MAR 16 2007 .DISCUSSION...CURRENTLY LONG WAVE TROUGH WITH AXIS FROM GREAT LAKES TO WRN GULF OF MEX. A SHORT WAVE MOVING ARND THE BASE OF THE TROUGH AND ACROSS FL PENINSULA HELPING TO DESTABILIZE THE LOCAL ATMOSPHERE WITH GOOD UPR LVL DIV. AMPLE LOW LEVEL MOISTURE AND DIURNAL HEATING PROVIDING ENERGY FOR SHWRS/STORMS THIS AFTERNOON. EXPECT STORMS TO CONTINUE TO DEVELOP OVER INTERIOR SECTIONS THIS AFTERNOON AND THEN MOVE QUICKLY NORTHEAST OVER ERN METRO AREAS. LOW LVL WIND PROFILES FROM ACARS AND DOPPLER RADAR SHOW GOOD VERTICAL DIR/SPEED SHEAR OVER EXTREME SRN PENINSULA INDICATING THE POSSIBILITY OF SOME STORMS BECOMING SEVERE (SUPERCELL TYPE). WL KEEP THAT IN THE FORECAST FOR REST OF THIS AFTERNOON AND EVENING HOURS. A COLD FRONT ACROSS CENTRAL FLORIDA THIS AFTERNOON WILL MOVE QUICKLY SE THIS EVENING AND CLEARING S. FLA JUST AFTER MIDNIGHT. A DRY AIRMASS WILL THEN SPREAD SOUTH AS A SFC HIGH MOVES TO ERN SEA BOARD. THIS WILL KEEP THE LOCAL AREA FREE OF CLOUDS/PRECIP AND COOL THROUGH THE WEEKEND. SUNDAY IS EXPECTED TO BE THE COOLEST DAY WITH MINS RANGING FROM ARND 40 ACROSS NRN INTERIOR TO L/M 50S OVR THE ERN METRO AREAS. THE SFC HIGH WILL THEN MOVE EAST OVER WRN ATLC MAKING THE LOW LVL FLOW TO SHIFT EAST AND BRINGING A RETURN TO MORE SEASONAL WX PATTERN TO S. FL. THIS PATTERN WILL CONTINUE FOR THE REST OF THE EXTENDED PORTION OF THE FORECAST. && .AVIATION...THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS AFTERNOON FOCUSED INTERIOR/ATLANTIC COAST. PLACED TEMPO TSRA IN FOR THE EAST COAST TERMINALS THROUGH 23Z...SINCE THIS TIME PERIOD STANDS THE BEST PROBABILITIES FOR THUNDERSTORMS. WINDS WILL PREVAIL OUT OF THE S-SW BECOMING NW AT AROUND MIDNIGHT AS THE COLD FRONT CLEARS THE AREA OVERNIGHT. && .MARINE...SFC WINDS SHOULD SHIFT TO NORTH RIGHT BEHIND THE FRONT LATE TONIGHT. SEAS IN THE GULF STREAM WILL REACT BY BUILDING UP TO 10 FT BY SATURDAY AFTERNOON AND REMAINING AT THAT HEIGHT THROUGH SUNDAY. WILL MENTION EXERCISE CAUTION FOR THE ATLANTIC WATERS AS WINDS WILL INCREASE FROM THE SW JUST AHEAD OF THE FRONT TONIGHT. && .FIRE WEATHER...RELATIVE HUMIDITIES ARE EXPECTED TO FALL TO BELOW 35 PERCENT ACROSS INTERIOR SECTIONS SAT AFTERNOON AS DRY AIR SPREAD SOUTH ACROSS SOUTH FLORIDA. WL KEEP A FIRE WEATHER WATCH AND LET EVENING/MIDNIGHT CREW DECIDE WHETHER TO ISSUE A RED FLAG WARNING OR NOT. SIMILAR CONDITIONS COULD OCCUR SUNDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 59 72 51 73 / 30 - - 10 FORT LAUDERDALE 60 74 55 73 / 40 10 - 10 MIAMI 61 75 52 75 / 40 10 - 10 NAPLES 61 70 47 72 / 20 - - - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...FIRE WEATHER WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR FLZ063-FLZ066-FLZ067-FLZ068-FLZ069-FLZ070- FLZ071-FLZ072-FLZ073-FLZ074-FLZ075. AM...NONE. GM...NONE. && $$ LONG TERM/SHORT TERM/MARINE/FIRE WEATHER...47/RGH SHORT TERM/AVIATION...57/DG