AREA FORECAST DISCUSSION...UPDATED
NWS UPTON NY
1005 AM EST MON FEB 19 2007
.NEAR TERM (THIS AFTERNOON AND TONIGHT)...
TROUGH AXIS EAST OF THE AREA THIS MORNING...AND STRONG COLD AIR
ADVECTION WILL BE SHUTTING DOWN SOON AS RIDGE BUILDS IN QUICKLY. IN
FACT...EXPECT RIDGE AXIS OVER AREA BY THIS EVENING...THEN WARM AIR
ADVECTION PREVAILS ON W/SW RETURN FLOW OVERNIGHT.
HAVE UPDATED GRIDS TO REFLECT LATEST CONDITIONS...AND AFTERNOON HIGH
TEMPS LOOK REASONABLE WITH MAYBE A DEGREE OR TWO CUT WITH THIS
UPDATE.
OTHERWISE...I DO EXPECT WINDS TO GRADUALLY DIMINISH...ALONG WITH
LITTLE CLOUD COVER THIS AFTERNOON (MOSTLY CLEAR SKIES WITH JUST A
BIT OF INSTABILITY STRATO-CU GIVING WAY TO INCREASING CIRRUS LATE IN
THE DAY AHEAD OF RIDGING).
GUSTY NW WINDS WILL QUICKLY DIMINISH THIS EVENING AND THEN BACK TO
THE SW AFTER MIDNIGHT AS SURFACE RIDGE AXIS SLIDES ACROSS THE REGION
AS MENTIONED EARLIER. TEMPS SHOULD INITIALLY RADIATE WELL
TONIGHT...ESPECIALLY EASTERN HALF OF CWA...WITH LIGHT WINDS AND
BEFORE CIRRUS THICKENS. BUT STRENGTHENING RETURN FLOW AND WAA LATE
TONIGHT AND THICKENING CIRRUS SHOULD HAVE TEMPS CLIMBING LATE
TONIGHT...ESPECIALLY CITY/COAST. WILL STAY CLOSE TO MAV NUMBERS TO
ACCOUNT FOR RADIATIONAL COOLING EARLY.
&&
.SHORT TERM (TUESDAY THROUGH WEDNESDAY)...
NEAR ZONAL FLOW BECOMES SLIGHTLY RIDGED ON EAST COAST AS MODELS ARE
COMING INTO BETTER AGREEMENT WITH A NORTHERN STREAM SHORTWAVE
CROSSING THE NORTHERN PLAINS MONDAY NIGHT AND INTO THE NORTHEAST
TUESDAY NIGHT...WHILE SOUTHERN STREAM CUTOFF GETS SHEARED FROM
SOUTHWEST INTO SOUTHERN PLAINS DURING THIS TIME. NAM APPEARS TO BE
OUTLIER WITH LEAVING SOUTHERN STREAM SYSTEM ACROSS THE SW
STATES...LEADING TO A DRIER AND QUICKER SYSTEM FOR TUESDAY NIGHT.
WILL GO WITH LESS PROGRESSIVE AND WETTER ECMWF/CANREG/GFS/UKMET
SOLUTION.
LOW PRESSURE TRACKING THROUGH THE GREAT LAKES MONDAY NIGHT WILL
WEAKEN AS IT TRACKS EAST THROUGH CENTRAL NY AND NEW ENGLAND ON
TUESDAY. SW FLOW AHEAD OF THE SYSTEM WILL PROVIDE ENOUGH THETA-E
ADVECTION AND ISENTROPIC LIFT FOR CLOUDS TO LOWER AND THICKEN AND
SCATTERED SHOWER TO DEVELOP IN THE MORNING.
WITH FORCING WEAK EXPECT ACTIVITY TO BE LIGHT BUT TAPPING ENOUGH
GULF MOISTURE WITH SOUTHERN STREAM WAVE CONTRIBUTION TO HAVE A
WIDESPREAD MEASURABLE EVENT. SREF IN AGREEMENT WITH THIS THINKING
AND OPERATIONAL SUITE...DEPICTING HIGH LIKELY CONFIDENCE FOR AT
LEAST
.05" QPF. SO WILL GO INCREASING CHANCE POPS THROUGH THE LATE
AFTERNOON AND THEN LIKELY TUESDAY NIGHT WITH BEST MOISTURE
CONVERGENCE/LIFT AHEAD OF THE APPROACHING SHORTWAVE AND AS WEAK LOW
PRESSURE AND ASSOCIATED COLD FRONT CROSS THE REGION.
MODELS INITIALLY SUPPORT SNOW/SLEET EARLY TUESDAY...MAINLY ACROSS
NORTHERN SECTIONS...BUT THEN CHANGING TO RAIN FROM S TO N WITH
CONTINUED WAA IN THE AFTERNOON. WAA FLOW RAISES 950 HPA TEMPS TO 2
TO 3 C BY TUESDAY AFTERNOON...WHICH WITH FULL MIXING TO THAT LEVEL
WOULD MEAN MID TO UPPER 40S. BUT WITH CLOUD COVER AND SHOWER
ACTIVITY WILL GO MORE IN THE LOWER TO MID 40 RANGE. A DEGREE OR TWO
BELOW GUIDANCE.
AS COLD FRONT CROSSES THE REGION LATE TUESDAY EVENING...MODEL
SOUNDINGS ARE SHOWING SUFFICIENT COLUMN COOLING ACROSS INTERIOR
LOWER HUDSON VALLEY AND THEN INTERIOR SOUTHERN CONNECTICUT FOR A
CHANGEOVER TO A BRIEF PERIOD OF SNOW BEFORE LIFT/MOISTURE AXIS
SLIDES OFFSHORE. THIS WOULD GENERALLY AMOUNT TO AN INCH OR LESS OF
SNOW ACCUMULATION. COULD EVEN HAVE A FEW WET SNOW FLAKES MIX IN ALL
THE WAY TO THE CITY/COAST...WITH NO ACCUM.
HIGH PRESSURE BUILDS IN FOR WEDNESDAY WITH MOSTLY SUNNY SKIES.
AIRMASS BEHIND COLD FRONT IS OF PAC ORIGIN...AND WITH DOWNSLOPE
COMPONENT TO FLOW TEMPERATURES SHOULD RISE TO NEAR OR SLIGHTLY ABOVE
SEASONABLE (LOW TO MID 40S).
&&
.LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...
HIGH PRESSURE BUILDS INTO THE CWA ON WEDNESDAY NIGHT AND REMAINS IN
PLACE FOR MUCH OF THE LONG TERM PERIOD. WEATHER WILL BE DRY AND HIGH
TEMPERATURES WILL BE IN THE UPPER 30S AND 40S. THE NEXT CHANCE OF
SIGNIFICANT WEATHER COULD COME LATE NEXT WEEKEND INTO EARLY NEXT
WEEK AS A LARGE AREA OF LOW PRESSURE IS EXPECTED TO MOVE ACROSS THE
MIDSECTION OF THE COUNTRY.
&&
.AVIATION...
HIGH PRESSURE IS QUICKLY BUILDING TOWARD TERMINALS THIS MORNING.
LOW PRESSURE WILL APPROACH FROM THE GREAT LAKES TOMORROW. UNLIMITED
VISIBILITY TODAY AND SCATTERED STRATO CUMULUS (RESIDUAL LAKE EFFECT
STREAMERS).
WINDS REMAIN THE IMPACT THIS AFTERNOON WITH A TIGHT PRESSURE
GRADIENT BETWEEN THE DEPARTING LOW AND THE UPSTREAM HIGH. WINDS DO
SUBSIDE THIS AFTERNOON AS THE RIDGE OF THE HIGH PRESSURE REACHES THE
REGION AND THE DIRECTION BACKS TO THE WEST.
THIS FAVORS THE 22`S AT KEWR.
EXPECT LOW LEVEL LIGHT TO MODERATE TURBC FOR THE GA FOLKS - CHECK
FOR AWC AIRMETS. ACARS AND MORNING OFFICE SOUNDING INDICATE 50 KTS
UP A FEW THOUSAND FEET.
OUTLOOK...TOMORROW REMAINS VFR WITH CIGS AROUND 050 WITH SOUTHWEST
(230) FLOW GUSTING INTO THE UPPER 20S IN THE AFTERNOON. CIGS FALL IN
THE AFTERNOON WITH MVFR PERHAPS SOME IFR AS EARLY AS TUESDAY EVENING.
&&
.MARINE...
THE TIGHT PRESSURE GRADIENT BETWEEN THE DEPARTING LOW AND HIGH TO
THE WEST CONTINUES TO PRODUCE GALES FOR ALL WATERS AT THIS TIME.
THE PRESSURE GRADIENT WILL RELAX THIS AFTERNOON AS THE RIDGE OF HIGH
PRESSURE BUILDS IN. SEAS GRADUALLY SUBSIDE INTO THE OVERNIGHT PERIOD.
FREEZING SPRAY CONTINUES UNTIL WINDS RELAX BY EARLY AFTERNOON. LOW
WATER ADVISORY WILL BE AN ISSUE THROUGH THE NEXT LOW TIDE
CYCLE...WHICH IS MID AFTERNOON ACROSS WESTERN OCEAN AND NY HARBOR
ZONES...AND EARLY EVENING FOR WESTERN LI SOUND.
WINDS WILL PICK UP ONCE AGAIN ON TUESDAY (SMALL CRAFT
CONDITIONS)...WITH A RETURN SOUTHWESTERLY FLOW (AROUND THE HIGH) AS
THE HIGH MOVES OFFSHORE WELL TO OUR SOUTH. APPROACHING LOW MOVING
THROUGH THE GREAT LAKES REGION WILL MOVE ACROSS THE REGION TUE
NIGHT...BEFORE WEAK HIGH PRESSURE SETTLES ACROSS THE AREA BY LATE
WED AFTERNOON AND NIGHT. ANOTHER WEAK AREA OF LOW PRESSURE WILL MOVE
ACROSS NEW ENGLAND THU AFTERNOON. HIGH PRESSURE BUILDS IN FROM THE
WEST ON FRIDAY.
&&
.HYDROLOGY...
DRY WEATHER IS THEN EXPECTED UNTIL TUE/TUES NIGHT...WHEN ONE TO TWO
TENTHS QPF AMOUNTS ARE EXPECTED. PART OF THAT MAY BE IN FORM OF SNOW
ACROSS INTERIOR LOWER HUDSON VALLEY AND INTERIOR SOUTHERN CONN.
WITH ICE ON AREA RIVERS AND STREAMS...STAGE LEVELS MAY FLUCTUATE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...LOW WATER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ338-
355.
GALE WARNING UNTIL 6 PM EST THIS AFTERNOON FOR ANZ330-335-338-
350-353-355.
LOW WATER ADVISORY UNTIL 8 PM EST THIS EVENING FOR ANZ335.
&&
$$
NEAR TERM UPDATE/AVIATION/MARINE...PW
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
949 PM EST TUE FEB 20 2007
.UPDATE...
EVE SOUNDINGS INDICATED A LITTLE MORE FAVORABLE LOW LEVEL
HYDROLAPSE FOR DENSE FOG DEVELOPMENT THAN SUGGESTED BY PRE-00Z
TAMDAR DATA. PATCHY DENSE FOG BEING REPORTED ALREADY THIS EVENING
BY AUTOMATED SURFACE OBS AND SPOTTERS. SOME CIRRUS MOVG INTO THE
AREA ATTM BUT SHOULD BE SHORT LIVED AND NOT EXPECTED TO BE
SUFFICIENT TO LIMIT FURTHER RADIATIONAL COOLING. THUS, EXPECT FOG
TO CONT TO LOWER VSBYS AND BECOME MORE WIEDSPREAD OVERNIGHT AS SFC
HIGH MOVES ACROSS THE AREA. OTHER PROBLEM THIS EVENING IS WITH
BLACK ICE. MELTING SNOW WAS RAPIDLY REFREEZING THIS EVENING DUE TO
THE STRONG RADIATIONAL COOLING, ESPECIALLY ON BLACKTOP. THIS WILL
RESULT IN ICY SPOTS ON ROADS/SIDEWALKS OVERNIGHT AND WED MORNING.
DENSE FOG SHOULD ALSO RESULT IN SOME ADDITIONAL GLAZING WITH
GROUND SURFACES ALREADY VERY MOIST AND TEMPERATURES FALLING WELL
BLO FREEZING. THUS, ISSUED A FREEZING FOG ADVISORY OVERNIGHT
UNTIL 15Z WED. NO OTHER SGFNT CHANGES ATTM AS GOING LOWS IN THE
L-M20S LOOK REASONABLE.
&&
.PREV DISCUSSION... /ISSUED 644 PM EST TUE FEB 20 2007/
UPDATE...
UPDATED MAINLY TO FRESHEN WORDING IN ZONES AS SHOWERS HAVE MOVED
EAST OUT OF THE CWA EARLY THIS EVENING. REST OF THE NIGHT SHOULD
BE DRY WITH RADIATIONAL COOLING FOG/STRATUS DVLPG AS SFC HIGH
MOVES ACROSS THE AREA.
PREV DISCUSSION... /ISSUED 630 PM EST TUE FEB 20 2007/
AVIATION...
SKIES HAVE CLEARED OVER NRN INDIANA THIS EVENING IN THE WAKE OF A
WK SHRTWV WHICH MOVED THROUGH THE AREA THIS AFTN. A WK AREA OF
HIGH PRESSURE WILL MOVE ACROSS THE AREA TONIGHT PROVIDING LIGHT
WINDS. SFC DWPTS HAVE NOT LOWERED SIGNIFICANTLY OVER NRN INDIANA THIS
AFTN, AND WITH LIGHT WINDS OVER THE AREA TONIGHT SGFNT DRY
ADVECTION AT THE SFC NOT EXPECTED. HWVR, RECENT NEARBY TAMDAR DATA
WAS INDICATING A NEGATIVE HYDROLAPSE IN THE LOW LEVELS SUGGESTING
THAT THE MOIST LAYER OVER THE AREA IS QUITE SHALLOW. THUS, DIDN`T
CHANGE PREVIOUS FCST DRASTICALLY BUT GIVEN LACK OF DRIER AIR MOVG
IN AT THE SFC THIS AFTN, DID LOWER VSBYS TO 1SM IN BR AT BOTH
TERMINALS OVERNIGHT. INCREASING SWLY GRADIENT AHEAD OF ANOTHER
CDFNT DROPPING SEWD INTO WI/IL SHOULD ALLOW FOG/STRATUS TO MIX OUT
DURING THE DAY WED, HWVR WITH WK FLOW CONTINUING IN THE MORNING
EXPECT IMPROVEMENT WILL BE SLOW.
PREV DISCUSSION... /ISSUED 311 PM EST TUE FEB 20 2007/
SHORT TERM...
SEVERAL FORECAST CHALLENGES FOR THE SHORT TERM PACKAGE. SHORT WAVE
RACING OUT OF ILLINOIS WILL EXIT THE AREA EARLY THIS EVENING. VIS
IMAGES SHOWING CLEARING NEAR THE IN/IL STATE LINE. THIS CLEARING
SHOULD PROGRESS EAST ACROSS THE FORECAST AREA THIS EVENING. HIGH
PRESSURE WILL SETTLE ACROSS THE AREA LEADING TO LIGHT OR CALM WINDS.
THE COMBINATION OF THESE FACTORS WITH MELTING SNOWPACK AND SOME
LIGHT RAINFALL TODAY WILL SET THE STAGE FOR POSSIBLE FOG AND STRATUS
DEVELOPMENT TONIGHT. NAM AND GFS HAVE DIFFERENT IDEAS ON WHAT WILL
OCCUR...WITH THE NAM MORE PESSIMISTIC...SHOWING A STRONG RADIATION
INVERSION DEVELOPING AND STRATUS AND FOG FORMING UNDER IT. GFS DOES
NOT DEVELOP THIS. THE ONLY NEGATIVE FACTOR FOR FOG AND STRATUS IS
THE DRYING OCCURING UPSTREAM THIS AFTERNOON WITH SURFACE DEWPOINTS
DROPPING INTO THE MID AND UPPER 20S. HOWEVER...GIVEN ALL THE OTHER
POSITIVE FACTORS AND STAYING WITH PERSISTENCE AND CONTINUITY OF
PRESENT FORECAST...WILL CONTINUE FOG AND STRATUS FORMATION
OVERNIGHT. HENCE SKIES BECOMING MOSTLY CLEAR THIS EVENING...THEN
MOSTLY CLOUDY AFTER MIDNIGHT WITH STRATUS AND FOG DEVELOPMENT.
SHOULD TAKE SOME TIME TO BURN OFF FOG AND STRATUS WEDNESDAY.
INCREASING FLOW IN THE AFTERNOON SHOULD HELP SCATTER THINGS OUT.
WITH CLEAR SKIES THIS EVENING AND STILL RESIDUAL SNOWPACK...SHOULD
SEE TEMPS DROP QUICKLY THEN LEVEL OUT WHEN FOG FORMS. TEMPS TRICKY
ON WEDNESDAY DEPENDING ON HOW FAST FOG MIXES OUT. AGAIN STAYED WITH
PERSISTENCE FOR NOW WHICH FALLS NEAR THE LOW END OF MOS GUIDANCE.
LONG TERM....
WEDNESDAY THROUGH TUESDAY...
WEATHER PATTERN CONTINUES TO DEAMPLIFY ACROSS THE UNITED STATES. A
FAIRLY STRONG SHORT WAVE SYSTEM WILL PASS NORTH OF THE AREA
WEDNESDAY NIGHT WITH ANOTHER COLD FRONT EXPECTED TO PASS ACROSS THE
AREA. MOISTURE IS LIMITED BEING MOSTLY TRAPPED IN THE LOWEST 5KFT.
MODEL GUIDANCE PUSHES SOME LIFT ACROSS THE AREA AT THE SAME
TIME...BUT WITH LIMITED MOISTURE...ELECTED TO KEEP WEDNESDAY NIGHT
DRY. MINOR CHANGES WERE MADE TO THE LOW TEMPERATURE FORECAST.
ONCE THIS SYSTEM IS PAST...A STRONG MID LEVEL RIDGE OF HIGH PRESSURE
WILL PASS ACROSS THE AREA THURSDAY AND FRIDAY. COLD AIR WILL MOVE
ACROSS THE AREA...BUT ARCTIC AIR MASSES WILL REMAIN WELL NORTH OF
THE WESTERN LOWER GREAT LAKES REGION. MADE MINOR CHANGES TO
TEMPERATURES FORECASTS FOR THURSDAY AND FRIDAY. THIS RIDGE IS BEING
GENERATED BY A STRONG SHORT WAVE TROF DIGGING INTO THE WEST COAST
AREA. THESE TWO SYSTEMS WILL DEVELOP A MAJOR SURFACE LOW PRESSURE
SYSTEM OVER EASTERN COLORADO AND WESTERN KANSAS. BOTH THE ECMWF/GFS
PLACE THE SYSTEM THERE...WITH THE ECMWF MOVING THE LOW FASTER THAN
THE GFS. WITH TIMING UNCERTAINTY HAVE ELECTED TO KEEP THE CURRENT
FORECAST OF RAIN DURING THE DAY SATURDAY AND INTO SUNDAY.
HOWEVER...THERE CHANCES ARE INCREASING THAT THE PRECIPITATION MAY
HOLD OFF INTO SATURDAY AFTERNOON. MINOR CHANGES WERE MADE TO THE
HIGH TEMPERATURE FORECAST FOR SATURDAY...LOWERING THEM IN OUR NORTH.
THE POTENTIAL EXISTS FOR HEAVY RAIN BOTH SATURDAY AND SUNDAY ALONG
WITH AN INCREASED CHANCE OF FLOODING. WITH A MORE PROGRESSIVE ZONAL
FLOW EXPECTED TO CONTINUE ACROSS THE AREA ANOTHER...SHORT WAVE
SYSTEM WILL FOLLOW BRINGING A CHANCE OF SNOW ON MONDAY AND SNOW WITH
RAIN SOUTH ON TUESDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING FOG ADVISORY UNTIL 10 AM EST /9 AM CST/ WEDNESDAY FOR
INZ003>009-012>018-020-022>027-032>034.
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST WEDNESDAY FOR MIZ077>081.
OH...FREEZING FOG ADVISORY UNTIL 10 AM EST WEDNESDAY FOR OHZ001-002-
004-005-015-016-024-025.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM....LAMBERTY
AVIATION/UPDATE...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
644 PM EST TUE FEB 20 2007
.UPDATE...
UPDATED MAINLY TO FRESHEN WORDING IN ZONES AS SHOWERS HAVE MOVED
EAST OUT OF THE CWA EARLY THIS EVENING. REST OF THE NIGHT SHOULD
BE DRY WITH RADIATIONAL COOLING FOG/STRATUS DVLPG AS SFC HIGH
MOVES ACROSS THE AREA.
&&
.PREV DISCUSSION... /ISSUED 630 PM EST TUE FEB 20 2007/
AVIATION...
SKIES HAVE CLEARED OVER NRN INDIANA THIS EVENING IN THE WAKE OF A
WK SHRTWV WHICH MOVED THROUGH THE AREA THIS AFTN. A WK AREA OF
HIGH PRESSURE WILL MOVE ACROSS THE AREA TONIGHT PROVIDING LIGHT
WINDS. SFC DWPTS HAVE NOT LOWERED SIGNIFICANTLY OVER NRN INDIANA THIS
AFTN, AND WITH LIGHT WINDS OVER THE AREA TONIGHT SGFNT DRY
ADVECTION AT THE SFC NOT EXPECTED. HWVR, RECENT NEARBY TAMDAR DATA
WAS INDICATING A NEGATIVE HYDROLAPSE IN THE LOW LEVELS SUGGESTING
THAT THE MOIST LAYER OVER THE AREA IS QUITE SHALLOW. THUS, DIDN`T
CHANGE PREVIOUS FCST DRASTICALLY BUT GIVEN LACK OF DRIER AIR MOVG
IN AT THE SFC THIS AFTN, DID LOWER VSBYS TO 1SM IN BR AT BOTH
TERMINALS OVERNIGHT. INCREASING SWLY GRADIENT AHEAD OF ANOTHER
CDFNT DROPPING SEWD INTO WI/IL SHOULD ALLOW FOG/STRATUS TO MIX OUT
DURING THE DAY WED, HWVR WITH WK FLOW CONTINUING IN THE MORNING
EXPECT IMPROVEMENT WILL BE SLOW.
PREV DISCUSSION... /ISSUED 311 PM EST TUE FEB 20 2007/
SHORT TERM...
SEVERAL FORECAST CHALLENGES FOR THE SHORT TERM PACKAGE. SHORT WAVE
RACING OUT OF ILLINOIS WILL EXIT THE AREA EARLY THIS EVENING. VIS
IMAGES SHOWING CLEARING NEAR THE IN/IL STATE LINE. THIS CLEARING
SHOULD PROGRESS EAST ACROSS THE FORECAST AREA THIS EVENING. HIGH
PRESSURE WILL SETTLE ACROSS THE AREA LEADING TO LIGHT OR CALM WINDS.
THE COMBINATION OF THESE FACTORS WITH MELTING SNOWPACK AND SOME
LIGHT RAINFALL TODAY WILL SET THE STAGE FOR POSSIBLE FOG AND STRATUS
DEVELOPMENT TONIGHT. NAM AND GFS HAVE DIFFERENT IDEAS ON WHAT WILL
OCCUR...WITH THE NAM MORE PESSIMISTIC...SHOWING A STRONG RADIATION
INVERSION DEVELOPING AND STRATUS AND FOG FORMING UNDER IT. GFS DOES
NOT DEVELOP THIS. THE ONLY NEGATIVE FACTOR FOR FOG AND STRATUS IS
THE DRYING OCCURING UPSTREAM THIS AFTERNOON WITH SURFACE DEWPOINTS
DROPPING INTO THE MID AND UPPER 20S. HOWEVER...GIVEN ALL THE OTHER
POSITIVE FACTORS AND STAYING WITH PERSISTENCE AND CONTINUITY OF
PRESENT FORECAST...WILL CONTINUE FOG AND STRATUS FORMATION
OVERNIGHT. HENCE SKIES BECOMING MOSTLY CLEAR THIS EVENING...THEN
MOSTLY CLOUDY AFTER MIDNIGHT WITH STRATUS AND FOG DEVELOPMENT.
SHOULD TAKE SOME TIME TO BURN OFF FOG AND STRATUS WEDNESDAY.
INCREASING FLOW IN THE AFTERNOON SHOULD HELP SCATTER THINGS OUT.
WITH CLEAR SKIES THIS EVENING AND STILL RESIDUAL SNOWPACK...SHOULD
SEE TEMPS DROP QUICKLY THEN LEVEL OUT WHEN FOG FORMS. TEMPS TRICKY
ON WEDNESDAY DEPENDING ON HOW FAST FOG MIXES OUT. AGAIN STAYED WITH
PERSISTENCE FOR NOW WHICH FALLS NEAR THE LOW END OF MOS GUIDANCE.
LONG TERM....
WEDNESDAY THROUGH TUESDAY...
WEATHER PATTERN CONTINUES TO DEAMPLIFY ACROSS THE UNITED STATES. A
FAIRLY STRONG SHORT WAVE SYSTEM WILL PASS NORTH OF THE AREA
WEDNESDAY NIGHT WITH ANOTHER COLD FRONT EXPECTED TO PASS ACROSS THE
AREA. MOISTURE IS LIMITED BEING MOSTLY TRAPPED IN THE LOWEST 5KFT.
MODEL GUIDANCE PUSHES SOME LIFT ACROSS THE AREA AT THE SAME
TIME...BUT WITH LIMITED MOISTURE...ELECTED TO KEEP WEDNESDAY NIGHT
DRY. MINOR CHANGES WERE MADE TO THE LOW TEMPERATURE FORECAST.
ONCE THIS SYSTEM IS PAST...A STRONG MID LEVEL RIDGE OF HIGH PRESSURE
WILL PASS ACROSS THE AREA THURSDAY AND FRIDAY. COLD AIR WILL MOVE
ACROSS THE AREA...BUT ARCTIC AIR MASSES WILL REMAIN WELL NORTH OF
THE WESTERN LOWER GREAT LAKES REGION. MADE MINOR CHANGES TO
TEMPERATURES FORECASTS FOR THURSDAY AND FRIDAY. THIS RIDGE IS BEING
GENERATED BY A STRONG SHORT WAVE TROF DIGGING INTO THE WEST COAST
AREA. THESE TWO SYSTEMS WILL DEVELOP A MAJOR SURFACE LOW PRESSURE
SYSTEM OVER EASTERN COLORADO AND WESTERN KANSAS. BOTH THE ECMWF/GFS
PLACE THE SYSTEM THERE...WITH THE ECMWF MOVING THE LOW FASTER THAN
THE GFS. WITH TIMING UNCERTAINTY HAVE ELECTED TO KEEP THE CURRENT
FORECAST OF RAIN DURING THE DAY SATURDAY AND INTO SUNDAY.
HOWEVER...THERE CHANCES ARE INCREASING THAT THE PRECIPITATION MAY
HOLD OFF INTO SATURDAY AFTERNOON. MINOR CHANGES WERE MADE TO THE
HIGH TEMPERATURE FORECAST FOR SATURDAY...LOWERING THEM IN OUR NORTH.
THE POTENTIAL EXISTS FOR HEAVY RAIN BOTH SATURDAY AND SUNDAY ALONG
WITH AN INCREASED CHANCE OF FLOODING. WITH A MORE PROGRESSIVE ZONAL
FLOW EXPECTED TO CONTINUE ACROSS THE AREA ANOTHER...SHORT WAVE
SYSTEM WILL FOLLOW BRINGING A CHANCE OF SNOW ON MONDAY AND SNOW WITH
RAIN SOUTH ON TUESDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM....LAMBERTY
AVIATION/UPDATE...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
630 PM EST TUE FEB 20 2007
.AVIATION...
SKIES HAVE CLEARED OVER NRN INDIANA THIS EVENING IN THE WAKE OF A
WK SHRTWV WHICH MOVED THROUGH THE AREA THIS AFTN. A WK AREA OF
HIGH PRESSURE WILL MOVE ACROSS THE AREA TONIGHT PROVIDING LIGHT
WINDS. SFC DWPTS HAVE NOT LOWERED SIGNIFICANTLY OVER NRN INDIANA THIS
AFTN, AND WITH LIGHT WINDS OVER THE AREA TONIGHT SGFNT DRY
ADVECTION AT THE SFC NOT EXPECTED. HWVR, RECENT NEARBY TAMDAR DATA
WAS INDICATING A NEGATIVE HYDROLAPSE IN THE LOW LEVELS SUGGESTING
THAT THE MOIST LAYER OVER THE AREA IS QUITE SHALLOW. THUS, DIDN`T
CHANGE PREVIOUS FCST DRASTICALLY BUT GIVEN LACK OF DRIER AIR MOVG
IN AT THE SFC THIS AFTN, DID LOWER VSBYS TO 1SM IN BR AT BOTH
TERMINALS OVERNIGHT. INCREASING SWLY GRADIENT AHEAD OF ANOTHER
CDFNT DROPPING SEWD INTO WI/IL SHOULD ALLOW FOG/STRATUS TO MIX OUT
DURING THE DAY WED, HWVR WITH WK FLOW CONTINUING IN THE MORNING
EXPECT IMPROVEMENT WILL BE SLOW.
&&
.PREV DISCUSSION... /ISSUED 311 PM EST TUE FEB 20 2007/
SHORT TERM...
SEVERAL FORECAST CHALLENGES FOR THE SHORT TERM PACKAGE. SHORT WAVE
RACING OUT OF ILLINOIS WILL EXIT THE AREA EARLY THIS EVENING. VIS
IMAGES SHOWING CLEARING NEAR THE IN/IL STATE LINE. THIS CLEARING
SHOULD PROGRESS EAST ACROSS THE FORECAST AREA THIS EVENING. HIGH
PRESSURE WILL SETTLE ACROSS THE AREA LEADING TO LIGHT OR CALM WINDS.
THE COMBINATION OF THESE FACTORS WITH MELTING SNOWPACK AND SOME
LIGHT RAINFALL TODAY WILL SET THE STAGE FOR POSSIBLE FOG AND STRATUS
DEVELOPMENT TONIGHT. NAM AND GFS HAVE DIFFERENT IDEAS ON WHAT WILL
OCCUR...WITH THE NAM MORE PESSIMISTIC...SHOWING A STRONG RADIATION
INVERSION DEVELOPING AND STRATUS AND FOG FORMING UNDER IT. GFS DOES
NOT DEVELOP THIS. THE ONLY NEGATIVE FACTOR FOR FOG AND STRATUS IS
THE DRYING OCCURING UPSTREAM THIS AFTERNOON WITH SURFACE DEWPOINTS
DROPPING INTO THE MID AND UPPER 20S. HOWEVER...GIVEN ALL THE OTHER
POSITIVE FACTORS AND STAYING WITH PERSISTENCE AND CONTINUITY OF
PRESENT FORECAST...WILL CONTINUE FOG AND STRATUS FORMATION
OVERNIGHT. HENCE SKIES BECOMING MOSTLY CLEAR THIS EVENING...THEN
MOSTLY CLOUDY AFTER MIDNIGHT WITH STRATUS AND FOG DEVELOPMENT.
SHOULD TAKE SOME TIME TO BURN OFF FOG AND STRATUS WEDNESDAY.
INCREASING FLOW IN THE AFTERNOON SHOULD HELP SCATTER THINGS OUT.
WITH CLEAR SKIES THIS EVENING AND STILL RESIDUAL SNOWPACK...SHOULD
SEE TEMPS DROP QUICKLY THEN LEVEL OUT WHEN FOG FORMS. TEMPS TRICKY
ON WEDNESDAY DEPENDING ON HOW FAST FOG MIXES OUT. AGAIN STAYED WITH
PERSISTENCE FOR NOW WHICH FALLS NEAR THE LOW END OF MOS GUIDANCE.
LONG TERM....
WEDNESDAY THROUGH TUESDAY...
WEATHER PATTERN CONTINUES TO DEAMPLIFY ACROSS THE UNITED STATES. A
FAIRLY STRONG SHORT WAVE SYSTEM WILL PASS NORTH OF THE AREA
WEDNESDAY NIGHT WITH ANOTHER COLD FRONT EXPECTED TO PASS ACROSS THE
AREA. MOISTURE IS LIMITED BEING MOSTLY TRAPPED IN THE LOWEST 5KFT.
MODEL GUIDANCE PUSHES SOME LIFT ACROSS THE AREA AT THE SAME
TIME...BUT WITH LIMITED MOISTURE...ELECTED TO KEEP WEDNESDAY NIGHT
DRY. MINOR CHANGES WERE MADE TO THE LOW TEMPERATURE FORECAST.
ONCE THIS SYSTEM IS PAST...A STRONG MID LEVEL RIDGE OF HIGH PRESSURE
WILL PASS ACROSS THE AREA THURSDAY AND FRIDAY. COLD AIR WILL MOVE
ACROSS THE AREA...BUT ARCTIC AIR MASSES WILL REMAIN WELL NORTH OF
THE WESTERN LOWER GREAT LAKES REGION. MADE MINOR CHANGES TO
TEMPERATURES FORECASTS FOR THURSDAY AND FRIDAY. THIS RIDGE IS BEING
GENERATED BY A STRONG SHORT WAVE TROF DIGGING INTO THE WEST COAST
AREA. THESE TWO SYSTEMS WILL DEVELOP A MAJOR SURFACE LOW PRESSURE
SYSTEM OVER EASTERN COLORADO AND WESTERN KANSAS. BOTH THE ECMWF/GFS
PLACE THE SYSTEM THERE...WITH THE ECMWF MOVING THE LOW FASTER THAN
THE GFS. WITH TIMING UNCERTAINTY HAVE ELECTED TO KEEP THE CURRENT
FORECAST OF RAIN DURING THE DAY SATURDAY AND INTO SUNDAY.
HOWEVER...THERE CHANCES ARE INCREASING THAT THE PRECIPITATION MAY
HOLD OFF INTO SATURDAY AFTERNOON. MINOR CHANGES WERE MADE TO THE
HIGH TEMPERATURE FORECAST FOR SATURDAY...LOWERING THEM IN OUR NORTH.
THE POTENTIAL EXISTS FOR HEAVY RAIN BOTH SATURDAY AND SUNDAY ALONG
WITH AN INCREASED CHANCE OF FLOODING. WITH A MORE PROGRESSIVE ZONAL
FLOW EXPECTED TO CONTINUE ACROSS THE AREA ANOTHER...SHORT WAVE
SYSTEM WILL FOLLOW BRINGING A CHANCE OF SNOW ON MONDAY AND SNOW WITH
RAIN SOUTH ON TUESDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM....LAMBERTY
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
250 PM EST MON FEB 19 2007
.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
A BREEZY AFTERNOON ACROSS THE ENTIRE LOWER OHIO VALLEY...AHEAD OF
LOW PRES/COLD FRONT CURRENTLY OVER MIDWEST AND PLAINS STATES. BASED
ON BUFKIT DIAGNOSTICS...EXPECT WIND GUSTS TO 30 OR 35 MPH THROUGH
THE BALANCE OF THE AFTERNOON...WILL CONTINUE MENTIONING IN HWO.
CONSENSUS OF 12Z NAM/GFS/RUC OUTPUT INDICATES THAT WINDS WILL LIKELY
STAY UP TONIGHT ASSOC WITH STRONG LLJ (50-60KTS BETWEEN 800-900MB).
THIS WOULD RESULT IN TEMPS FALLING WITH SUNSET...BUT THEN STEADYING
OUT FOR THE REMAINDER OF THE OVERNIGHT HOURS...EVEN RISING SLIGHTLY
TOWARD 12Z/TUE AS FRONT APPROACHES.
PCPN IS EXPECTED TO DEVELOP INTO THE MORNING HOURS TUESDAY ASSOC
WITH LIFT FROM COLD FRONT AND STRONG UPPER LEVEL JET STREAK. MODELS
HAVE SLOWED DOWN PCPN AS COMPARED TO YESTERDAY`S SOLUTIONS...AND
THERE ARE A NUMBER OF DIFFERENCES IN PRECIP SOLUTIONS TUESDAY IN THE
VARIOUS MODELS...WITH GFS EVEN PRODUCING SOME -SHRA AFTER MIDNIGHT
TONIGHT OVER THE REGION WITHIN STRONG WAA. WILL CONTINUE SLIGHT
CHANCE FOR -SHRA OVERNIGHT GIVEN THIS POSSIBILITY...BUT THE MOST
WIDESPREAD PCPN WILL BE TUESDAY INTO TUESDAY EVENING. GFS PRODUCES A
STREAK OF QPF OVER THE N 1/2 OF THE CWA TUE AFTN...WHILE NAM
PRODUCES THAT SAME FEATURE OVER SRN KY...AND MORE INTO THE EVENING
HOURS.
WILL BLEND THESE SOLUTIONS WHICH YIELDS 70-80% POPS OVER NEARLY THE
WHOLE CWA TUESDAY (MAINLY AFTER 15Z)...WITH PCPN CHANCES DIMINISHING
RAPIDLY FROM NW-SE AFTER 3Z TUES EVENING. AT LEAST A FEW
THUNDERSTORMS ARE EXPECTED OVER SRN KY TUES AFTN/EVE...AS BOTH
NAM/GFS BRING INSTABILITY INTO THE CWA JUST AHEAD OF THE FRONT. NAM
BRINGS A PLUME OF SUB-ZERO 850MB LI`S ACROSS DOWNSTATE KY...WHILE
GFS EVEN HAS SFC-LI ZERO LINE NEAR BWG AT 0Z/WED. THEREFORE WILL
FCST THUNDER CHANCES OVER SRN KY TUES AFTN/EVE...AND MENTION SOME
LOCALIZED GUSTY WINDS GIVEN STRONG DYNAMICS/SHEAR WITH THIS SYSTEM.
SPC DAY TWO SLIGHT RISK IS JUST ACROSS THE BORDER INTO WRN/CNTRL
TENN.
CS
.LONG TERM (WEDNESDAY THROUGH MONDAY)...
DECENT CONSISTENCY FROM THE LAST FEW DAYS IN THE LONG TERM
PERIOD...THOUGH SOME TIMING DIFFERENCES FOR THE LARGE SYSTEM OVER
THE WEEKEND HAVE NOT CLOSED ANY...ALSO SOME MINOR CHANGES IN THE
MODELS WITH RESPECT TO THE SYSTEMS IN THE NORTHERN STREAM MOVING
WELL NORTH OF THE AREA HAVING SOME INFLUENCE ON THE REGION. WITH
MANY DETAILS STILL BLURRED BY THE MANY DIFFERENT SOLUTIONS...WILL
TRY TO FOCUS THEM BY USING A CONSISTENT GFS MODEL THROUGH THE FRIDAY
TIMEFRAME THEN THE MREF MEAN MAINLY INTO NEXT WEEK...IT HAS SOLID
SUPPORT FROM THE OPERATIONAL ECMWF AND THE UKMET.
WEDNESDAY THROUGH FRIDAY...
WEAK SURFACE HIGH MOVING ACROSS THE OHIO VALLEY WITH FAIRLY ZONAL
FLOW OVER THE CONUS...WITH TROUGH STARTING TO DIG ACROSS THE WEST
COAST WITH INCREASING HEIGHTS OVER THE PLAINS...AND WEAK TROUGHING
ACROSS THE EAST AS SYSTEM EXITS THE NORTHERN GREAT LAKES AND MOVES
INTO THE FAR NE STATES. RIDGING STARTS TO DRIFT EAST AS THE
DEEPENING LOW MOVES ONSHORE. WAA LOOKS TO START TO DEVELOP LATER
FRIDAY AS THE RIDGING MOVES INTO THE OHIO VALLEY. H850 TEMPS LOOK
TO BE STEADY WEDNESDAY AND THURSDAY...AND GRADUALLY WARM FRIDAY.
EACH DAY LOOKS TO BE DRY THROUGHOUT...SO HAVE REMOVED ALL POPS FOR
FRIDAY WITH THE SLOWER MOISTURE RETURN AND SLOWER H500 LOW EJECTING
FROM THE DESERT SW.
SATURDAY AND SUNDAY...
MAIN FOCUS THIS PERIOD FALLS WITHIN THESE TWO DAYS...STRONG STORM
SYSTEM TO DEVELOP OVER THE CENTRAL PLAINS. STRONG WAA AHEAD OF THE
DEEPENING CYCLONE WITH WARM FRONT PUSHING ACROSS THE REGION
SATURDAY...MOST LIKELY IN THE MORNING/EARLY AFTERNOON. SFC LOW LOOKS
TO TRACK FROM NEAR THE PANHANDLE OF OK TO NEAR NW MO/SW IA BY
EVENING AND ON TOWARDS THE ARROWHEAD OF MN BY SUN LATE
AFTERNOON...DEEPENING AS IT PROGRESSES ACROSS THE PLAINS AND UPPER
MS VALLEY. GUSTY SOUTH WINDS LOOK TO REMAIN THROUGH THE DAY SATURDAY
INTO SUNDAY...THE GFS SHOWS GRADIENT WINDS NEARING 20 MPH THROUGH
THE NIGHT. HAVE RAISED TEMPS BOTH SATURDAY FOR HIGHS AND OVERNIGHT
INTO SUNDAY...AS WELL AS RAISING DEWPOINTS WITH RAIN BECOMING
LIKELY. PWATS NEAR 1 TO 1.1 INCHES LATE SATURDAY INTO SUNDAY...WHICH
IS CLOSE TO 3 STD DEVIATIONS ABOVE NORMAL...WITH A LIKELY SQUALL
LINE DEVELOPING IF THE MODEL SOLUTIONS/FORECAST HOLDS...RAINFALL
TOTALS WILL SURPASS .75 TO 1 INCH ACROSS MUCH OF THE FORECAST AREA.
COLD FRONT MOST LIKELY WILL PASS THROUGH THE FORECAST AREA SOMETIME
SUNDAY MORNING OR EARLY AFTERNOON AT THE LATEST...STILL SIGNIFICANT
TIMING DIFFERENCES AMONG THE MODELS.
STRONG LOW LEVEL JET CLOSE TO 60 OR 70 KTS WILL BE PRESENT BY EARLY
SUNDAY...ALONG WITH STRONG UPPER LEVEL JET MAX. SO DYNAMICS ARE
THERE...WILL BE JUST NEEDING SOME INSTABILITY AS MODELS ARE ONLY
HINTING AT THE SLIGHTEST OF CAPES/MARGINAL LIS ALONG A THIN LINE
MOVING ACROSS THE REGION SUNDAY MORNING. THERE IS SOME PRECEDENT FOR
THIS TO CREATE DECENT WINDS...A VERY SIMILAR LOOKING CASE ON 10 NOV
1998. THAT EVENT LOOKED JUST THE SAME WITH SLIGHT INVERTED UPPER
TROUGH WORKING ACROSS THE PLAINS INTO THE UPPER MS VALLEY...DEEP SFC
LOW AND STRONG WAA AHEAD OF THE SYSTEM...SOME CURRENT DIFFERENCES
ARE THAT THE UPPER LEVEL JET AND LOW LEVEL JET MAY BE SLIGHTLY LESS
THAN THE 98 CASE...AND H850 TEMPS REACHED JUST ABOVE 12C IN 98...
CURRENT MODELS SUGGEST ABOUT 10 TO 12C. THE 10 NOV 98 CASE PRODUCED
45 TO 60 KT WINDS ACROSS THE REGION WITH A THIN SQUALL LINE...22
STRONG WIND REPORTS IN KENTUCKY WITH 69 STRONG WIND REPORTS IN
INDIANA. SOMETHING TO CONTINUE TO WATCH THE NEXT FEW DAYS ON HOW
THIS STORM SYSTEM TRENDS.
MONDAY INTO NEXT WEEK...
COOLER AIR PUSHES INTO THE REGION BEHIND THE WEEKEND SYSTEM...WITH
DRAMATIC DROP IN H850 TEMPS FROM 10 TO 12 C TO AROUND -1 OR -2C BY
MONDAY MORNING. STRONG RIDGING ACROSS THE NORTHEAST CONUS AND THE
CANADIAN MARITIMES CREATES A SLIGHT BLOCK TO THE CLOSED LOW TRYING
TO MOVE NORTHEAST. HOLDING IT TEMPORARILY ACROSS THE NORTHERN GREAT
LAKES...BLOCKING RIDGE APPEARS TO BREAK DOWN WITH SE RIDGE BUILDING
AGAIN BY THE MIDDLE OF THE WEEK AND RETURN OF NORMAL TO ABOVE NORMAL
TEMPERATURES LOOKS LIKELY. SOME STRONG SUPPORT FROM THE
INDICES...THE NAO IS TRENDING POSITIVE...THE PNA REMAINS NEGATIVE
AND THE EPO POSITIVE THROUGH THE FIRST FEW DAYS OF MARCH.
SCHOTT
&&
.AVIATION (18Z TAFS)...
GUSTY SOUTHERLY WINDS WILL MAKE FOR A BUMPY RIDE THIS AFTN ACROSS
THE CWA. GUSTS NEARING 20-25KTS AS OF 17Z...AND BASED ON RECENT
NAM/RUC BUFKIT PROFILES EXPECT GUSTS TO 25-28KTS THIS AFTN AT THE
TAF SITES. LOW LEVEL JET FCST TO INCREASE THIS AFTN...LASTING INTO
TONIGHT...IN FACT 1655Z ACARS SOUNDING AT SDF ALREADY SHOWING CLOSE
TO 50KTS AT 3500FT MSL. LLJ WIND SPEEDS OF 40-50KTS LIKELY DOWN TO
2KFT AGL THROUGH TONIGHT. CIGS EXPECTED TO LOWER INTO MVFR CATEGORY
AFTER 6Z TONIGHT AHEAD OF SFC COLD FRONT. GFS IS QUICKER IN
DEVELOPING PRECIP OVERNIGHT...WHILE NAM DELAYS UNTIL AFTER 12Z/TUE.
WILL HOLD OFF MENTIONING PREVAILING -RA UNTIL AFTER 12Z...THOUGH A
FEW LIGHT -SHRA ARE POSSIBLE BETWEEN 9-12Z.
CS
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1210 PM EST MON FEB 19 2007
COR TIMESTAMP
.AVIATION (18Z TAFS)...
GUSTY SOUTHERLY WINDS WILL MAKE FOR A BUMPY RIDE THIS AFTN ACROSS
THE CWA. GUSTS NEARING 20-25KTS AS OF 17Z...AND BASED ON RECENT
NAM/RUC BUFKIT PROFILES EXPECT GUSTS TO 25-28KTS THIS AFTN AT THE
TAF SITES. LOW LEVEL JET FCST TO INCREASE THIS AFTN...LASTING INTO
TONIGHT...IN FACT 1655Z ACARS SOUNDING AT SDF ALREADY SHOWING CLOSE
TO 50KTS AT 3500FT MSL. LLJ WIND SPEEDS OF 40-50KTS LIKELY DOWN TO
2KFT AGL THROUGH TONIGHT. CIGS EXPECTED TO LOWER INTO MVFR CATEGORY
AFTER 6Z TONIGHT AHEAD OF SFC COLD FRONT. GFS IS QUICKER IN
DEVELOPING PRECIP OVERNIGHT...WHILE NAM DELAYS UNTIL AFTER 12Z/TUE.
WILL HOLD OFF MENTIONING PREVAILING -RA UNTIL AFTER 12Z...THOUGH A
FEW LIGHT -SHRA ARE POSSIBLE BETWEEN 9-12Z.
CS
&&
.UPDATE...
PRIMARY WX IMPACT OVER NEXT 6-9 HOURS WILL BE STRONG/GUSTY SOUTHERLY
WINDS DEVELOPING AHEAD OF SFC LOW PRES OVER UPPER MIDWEST. LATEST
BUFKIT DIAGNOSTICS FROM NAM/RUC INDICATE POTENTIAL FOR GUSTS TO NEAR
30 MPH TODAY IN OUR CWA. WILL MENTION THIS IN THE ZFP/HWO. REST OF
FORECAST LOOKS ON TRACK. NOT ENOUGH SNOW LEFT ON THE GROUND TO
REALLY AFFECT TEMPS...WHICH ARE FCST TO WARM TO SLIGHTLY ABOVE
NORMAL VALUES TODAY. MOST LOCATIONS HAVE NOT BEEN THIS WARM SINCE
JANUARY 27TH...23 DAYS AGO.
UPDATED FCST OUT BY 1030 AM EST.
CS
&&
.SHORT TERM (TODAY AND TONIGHT)...
SURFACE HIGH PRESSURE MOVING OFF THE GEORGIA COAST TODAY WILL
PROVIDE US WITH DRY WEATHER AND A GOOD AMOUNT OF SUNSHINE THROUGH
SCATTERED HIGH THIN CLOUDS. REMAINING SNOW COVER IS SHALLOW AND
PATCHY. VISIBLE SATELLITE LOOPS FROM YESTERDAY SHOW SNOWFIELD
DISAPPEARING QUICKLY OVER CENTRAL KENTUCKY WEST OF THE BLUE
GRASS...WITH TEMPERATURES ONLY RISING INTO THE LOWER AND MIDDLE 30S.
WITH GUSTY SOUTHWEST WINDS OF 15 TO 25 MPH AND GOOD SUN TODAY THE
SNOW PACK SHOULD NOT BE A MAJOR HINDRANCE TO RISING TEMPERATURES.
WILL KEEP THE BLUE GRASS AND SOME OF SOUTHERN INDIANA IN THE MIDDLE
40S BUT OTHER AREAS SHOULD SEE LOWER TO MIDDLE 50S.
TONIGHT A WEAKENING COLD FRONT WILL APPROACH FROM THE PLAINS...AND
BY 12Z TUESDAY WILL STRETCH FROM DETROIT TO SAINT LOUIS TO
AMARILLO. A FEW SMALL LIGHT RAIN SHOWERS MAY BREAK OUT AFTER
MIDNIGHT AS MOISTURE INCREASES AHEAD OF THE FRONT...BUT BY FAR THE
MAIN RAIN CHANCES WILL WAIT UNTIL THE DAYLIGHT HOURS TUESDAY.
13
.LONG TERM (TUESDAY-SUNDAY)...
SOUTHERLY FLOW AROUND RETREATING HIGH WILL KEEP GOOD SUPPLY OF
MOISTURE OVER THE AREA AHEAD OF ADVANCING COLD FRONT. SHOWERS THAT
BEGIN OVERNIGHT WILL QUICKLY INCREASE TO BECOME LIKELY OVER MUCH OF
THE AREA BY EARLY AFTERNOON. HIGHEST POPS WILL BE DURING THE
AFTERNOON HOURS. GFS IS INDICATING GOOD LIFT AHEAD OF FRONT. WILL
KEEP PRECIPITATION IN FORM OF RAIN SHOWERS. SPC INDICATED THUNDER
ONLY OVER THE EXTREME SOUTHERN PART OF FORECAST AREA AND WILL LEAVE
ANY MENTION OF THUNDER OUT OF FORECAST.
NAM IS QUICKEST BRINGING FRONT INTO FORECAST AREA FOLLOWED BY
GFS THEN ECMWF...UKMET AND GEM. WILL GO CLOSER TO THE MODEL
CONSENSUS WITH FRONT REACHING OHIO RIVER CLOSE TO 00Z. SHOWERS WILL
DECREASE RAPIDLY BEHIND THE FRONT WITH SHOWERS ENDING ACROSS ENTIRE
AREA BY SHORTLY AFTER 06Z.
TEMPERATURES ON TUESDAY WILL BE SIMILAR TO OR A DEGREE OR SO COOLER
THAN DAY BEFORE WITH CLOUDS AND SCATTERED TO NUMEROUS SHOWERS OVER
THE AREA. CLOUDS WILL DECREASE FROM THE NORTHWEST LATE TUESDAY
NIGHT WITH READINGS REACHING LOWER 30S ACROSS THE NORTH. HOWEVER
PRECIPITATION WILL HAVE ALREADY ENDED BEFORE TEMPERATURES WILL BE
COOL ENOUGH FOR A CHANGEOVER TO SNOW.
HIGH PRESSURE WILL PROVIDE PLENTY OF SUNSHINE WEDNESDAY AND THURSDAY
AND WITH ZONAL FLOW TEMPERATURES WILL STAY ON THE MILD SIDE.
NEXT SYSTEM MOVES IN ON FRIDAY THROUGH MUCH OF THE WEEKEND AND THIS
HAS POTENTIAL FOR THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. WILL
NOT MAKE CHANGES TO LATER PART OF FORECAST FOR NOW.
SCHOLZ
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1210 AM EST MON FEB 19 2007
.AVIATION (18Z TAFS)...
GUSTY SOUTHERLY WINDS WILL MAKE FOR A BUMPY RIDE THIS AFTN ACROSS
THE CWA. GUSTS NEARING 20-25KTS AS OF 17Z...AND BASED ON RECENT
NAM/RUC BUFKIT PROFILES EXPECT GUSTS TO 25-28KTS THIS AFTN AT THE
TAF SITES. LOW LEVEL JET FCST TO INCREASE THIS AFTN...LASTING INTO
TONIGHT...IN FACT 1655Z ACARS SOUNDING AT SDF ALREADY SHOWING CLOSE
TO 50KTS AT 3500FT MSL. LLJ WIND SPEEDS OF 40-50KTS LIKELY DOWN TO
2KFT AGL THROUGH TONIGHT. CIGS EXPECTED TO LOWER INTO MVFR CATEGORY
AFTER 6Z TONIGHT AHEAD OF SFC COLD FRONT. GFS IS QUICKER IN
DEVELOPING PRECIP OVERNIGHT...WHILE NAM DELAYS UNTIL AFTER 12Z/TUE.
WILL HOLD OFF MENTIONING PREVAILING -RA UNTIL AFTER 12Z...THOUGH A
FEW LIGHT -SHRA ARE POSSIBLE BETWEEN 9-12Z.
CS
&&
.UPDATE...
PRIMARY WX IMPACT OVER NEXT 6-9 HOURS WILL BE STRONG/GUSTY SOUTHERLY
WINDS DEVELOPING AHEAD OF SFC LOW PRES OVER UPPER MIDWEST. LATEST
BUFKIT DIAGNOSTICS FROM NAM/RUC INDICATE POTENTIAL FOR GUSTS TO NEAR
30 MPH TODAY IN OUR CWA. WILL MENTION THIS IN THE ZFP/HWO. REST OF
FORECAST LOOKS ON TRACK. NOT ENOUGH SNOW LEFT ON THE GROUND TO
REALLY AFFECT TEMPS...WHICH ARE FCST TO WARM TO SLIGHTLY ABOVE
NORMAL VALUES TODAY. MOST LOCATIONS HAVE NOT BEEN THIS WARM SINCE
JANUARY 27TH...23 DAYS AGO.
UPDATED FCST OUT BY 1030 AM EST.
CS
&&
.SHORT TERM (TODAY AND TONIGHT)...
SURFACE HIGH PRESSURE MOVING OFF THE GEORGIA COAST TODAY WILL
PROVIDE US WITH DRY WEATHER AND A GOOD AMOUNT OF SUNSHINE THROUGH
SCATTERED HIGH THIN CLOUDS. REMAINING SNOW COVER IS SHALLOW AND
PATCHY. VISIBLE SATELLITE LOOPS FROM YESTERDAY SHOW SNOWFIELD
DISAPPEARING QUICKLY OVER CENTRAL KENTUCKY WEST OF THE BLUE
GRASS...WITH TEMPERATURES ONLY RISING INTO THE LOWER AND MIDDLE 30S.
WITH GUSTY SOUTHWEST WINDS OF 15 TO 25 MPH AND GOOD SUN TODAY THE
SNOW PACK SHOULD NOT BE A MAJOR HINDRANCE TO RISING TEMPERATURES.
WILL KEEP THE BLUE GRASS AND SOME OF SOUTHERN INDIANA IN THE MIDDLE
40S BUT OTHER AREAS SHOULD SEE LOWER TO MIDDLE 50S.
TONIGHT A WEAKENING COLD FRONT WILL APPROACH FROM THE PLAINS...AND
BY 12Z TUESDAY WILL STRETCH FROM DETROIT TO SAINT LOUIS TO
AMARILLO. A FEW SMALL LIGHT RAIN SHOWERS MAY BREAK OUT AFTER
MIDNIGHT AS MOISTURE INCREASES AHEAD OF THE FRONT...BUT BY FAR THE
MAIN RAIN CHANCES WILL WAIT UNTIL THE DAYLIGHT HOURS TUESDAY.
13
.LONG TERM (TUESDAY-SUNDAY)...
SOUTHERLY FLOW AROUND RETREATING HIGH WILL KEEP GOOD SUPPLY OF
MOISTURE OVER THE AREA AHEAD OF ADVANCING COLD FRONT. SHOWERS THAT
BEGIN OVERNIGHT WILL QUICKLY INCREASE TO BECOME LIKELY OVER MUCH OF
THE AREA BY EARLY AFTERNOON. HIGHEST POPS WILL BE DURING THE
AFTERNOON HOURS. GFS IS INDICATING GOOD LIFT AHEAD OF FRONT. WILL
KEEP PRECIPITATION IN FORM OF RAIN SHOWERS. SPC INDICATED THUNDER
ONLY OVER THE EXTREME SOUTHERN PART OF FORECAST AREA AND WILL LEAVE
ANY MENTION OF THUNDER OUT OF FORECAST.
NAM IS QUICKEST BRINGING FRONT INTO FORECAST AREA FOLLOWED BY
GFS THEN ECMWF...UKMET AND GEM. WILL GO CLOSER TO THE MODEL
CONSENSUS WITH FRONT REACHING OHIO RIVER CLOSE TO 00Z. SHOWERS WILL
DECREASE RAPIDLY BEHIND THE FRONT WITH SHOWERS ENDING ACROSS ENTIRE
AREA BY SHORTLY AFTER 06Z.
TEMPERATURES ON TUESDAY WILL BE SIMILAR TO OR A DEGREE OR SO COOLER
THAN DAY BEFORE WITH CLOUDS AND SCATTERED TO NUMEROUS SHOWERS OVER
THE AREA. CLOUDS WILL DECREASE FROM THE NORTHWEST LATE TUESDAY
NIGHT WITH READINGS REACHING LOWER 30S ACROSS THE NORTH. HOWEVER
PRECIPITATION WILL HAVE ALREADY ENDED BEFORE TEMPERATURES WILL BE
COOL ENOUGH FOR A CHANGEOVER TO SNOW.
HIGH PRESSURE WILL PROVIDE PLENTY OF SUNSHINE WEDNESDAY AND THURSDAY
AND WITH ZONAL FLOW TEMPERATURES WILL STAY ON THE MILD SIDE.
NEXT SYSTEM MOVES IN ON FRIDAY THROUGH MUCH OF THE WEEKEND AND THIS
HAS POTENTIAL FOR THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. WILL
NOT MAKE CHANGES TO LATER PART OF FORECAST FOR NOW.
SCHOLZ
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
940 PM EST TUE FEB 20 2007
.UPDATE...
DEW POINTS CONTINUE TO CREEP UP WITH ARRIVAL OF RAIN AND WARM
ADVECTION THIS EVENING. COLD FRONTAL PASSAGE WILL BRING WEAK COLD
ADVECTION...ENOUGH TO BRING DEW POINT DEPRESSIONS NEAR ZERO IN SOME
LOCATIONS. CONSIDERING THIS WILL OCCUR ATOP A SNOW/SLEET
PACK...PATCHY OF FOG MAY OCCUR. GFS/ETA/NGM MOS GUIDANCE DOES NOT
SHOW MUCH IN THE WAY OF FOG...WHILE THE UPS FOG TECHNIQUE IS NOT
APPLICABLE GIVEN THE WARM ADVECTION TODAY AND COLD ADVECTION
EXPECTED LATER TONIGHT.
THE 21Z KLWX 6KM WRF-NMM DEPICTS PATCHY FOG DEVELOPING EAST OF THE
MOUNTAINS AFTER MIDNIGHT...WHILE THE 21Z RUC METEOGRAMS DEPICT
VISIBILITIES FALLING TO A MILE FROM KIAD NORTHEAST. ADDED MENTION OF
PATCHY FOG ACROSS THE NORTHERN FORECAST AREA...WHERE DEW POINT
DEPRESSIONS ARE EXPECTED TO BE THE LOWEST...AND MOST OF THE
SNOW/SLEET PACK REMAINS.
NO CHANGES TO THE FORECAST THINKING BELOW.
&&
.SHORT TERM...
WATER VAPOR LOOP SHOWS A SHEARED SHORT WAVE IS MOVING EAST ACROSS
THE LOWER GREAT LAKES. ACARS 400-250MB WIND OBSERVATIONS REVEAL A
POSITIVELY TILTED TROUGH ACROSS THE FOUR CORNERS...WITH A 170-190KT
WESTERLY JET FROM THE PLAINS THROUGH THE CAROLINAS. 20Z SURFACE
ANALYSIS PLACED A COLD FRONT FROM THE EASTERN GREAT LAKES SOUTHWEST
TOP A 1004MB CYCLONE ACROSS SOUTHERN MISSOURI. A WARM FRONT HAD
LIFTED NORTH INTO NEW ENGLAND. A TROUGH WAS LOCATED IN THE LEE OF
THE APPALACHIANS.
HAVE UPDATED THE FORECAST TO INCREASE POPS AS RAIN CROSSES THE
MOUNTAINS. BEST CHANCE FOR MEASURABLE PRECIPITATION IS ACROSS THE
WESTERN AND NORTHERN FORECAST AREA AS DEVELOPING DOWNSLOPE FLOW AND
SHEARING ALOFT SHOULD ACT TO DECREASE PRECIPITATION WITH TIME ACROSS
CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND. TIMING WAS ALSO
ADJUSTED BASED ON FASTER RADAR TRENDS. UPDATED FORECAST IS
CONSISTENT WITH TRENDS INDICATED BY THE 15Z SHORT RANGE ENSEMBLES AS
WELL.
WIND SHIFT WILL OCCUR WITH THE COLD FRONTAL PASSAGE OVERNIGHT FROM
NORTHWEST TO SOUTHEAST ACROSS THE REGION. TIMING OF THE COLD FRONT
AND MEAGER COLD AIR BEHIND THE BOUNDARY SHOULD PREVENT TEMPERATURES
FROM FALLING TOO QUICKLY.
WILL HAVE TO MONITOR FOR POSSIBLE FOG FORMATION OVERNIGHT AS
MOISTURE INCREASES ATOP THE SNOW/SLEET PACK.
&&
.AVIATION...
CEILINGS AND VISIBILITIES WILL DETERIORATE MOST LIKELY INTO TO MVFR
FLIGHT CATEGORY THIS EVENING AND EARLY TONIGHT AS AN AREA OF RAIN
MOVES INTO THE REGION. A COLD FRONTAL PASSAGE WILL TAKE PLACE FROM
THE NORTHWEST DURING THE MIDDLE OF THE NIGHT...PROVIDING A WIND
SHIFT TO THE NORTHWEST.
&&
.MARINE...
12Z MET/18Z MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS
DECREASE TO ABOUT 10KT THROUGH THE NIGHT. PROXIMITY 12Z GFS/18Z NAM
BUFKIT FORECAST SOUNDINGS INDICATE A 17-24KT WIND GUST POTENTIAL
NEAR KNHK THROUGH THE NIGHT. ICE COVERAGE HAS DECREASED DUE TO THE
WARMER TEMPERATURES.
&&
.TIDES...
CURRENT TIDAL DEPARTURES ARE A HALF FOOT BELOW ASTRONOMICAL
PREDICTIONS. THE LUNAR CYCLE IS WAXING TOWARD A QUARTER MOON (14
PERCENT FULL). THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND
THE NOAA EXTRATROPICAL STORM SURGE MODEL INDICATE DEPARTURES MAY
INCREASE TO A FOOT BELOW PREDICTED VALUES BY THE MORNING.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR
ANZ534-537.
&&
SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
640 PM EST TUE FEB 20 2007
.SHORT TERM...
WATER VAPOR LOOP SHOWS A SHEARED SHORT WAVE IS MOVING EAST ACROSS
THE LOWER GREAT LAKES. ACARS 400-250MB WIND OBSERVATIONS REVEAL A
POSITIVELY TILTED TROUGH ACROSS THE FOUR CORNERS...WITH A 170-190KT
WESTERLY JET FROM THE PLAINS THROUGH THE CAROLINAS. 20Z SURFACE
ANALYSIS PLACED A COLD FRONT FROM THE EASTERN GREAT LAKES SOUTHWEST
TOP A 1004MB CYCLONE ACROSS SOUTHERN MISSOURI. A WARM FRONT HAD
LIFTED NORTH INTO NEW ENGLAND. A TROUGH WAS LOCATED IN THE LEE OF
THE APPALACHIANS.
HAVE UPDATED THE FORECAST TO INCREASE POPS AS RAIN CROSSES THE
MOUNTAINS. BEST CHANCE FOR MEASURABLE PRECIPITATION IS ACROSS THE
WESTERN AND NORTHERN FORECAST AREA AS DEVELOPING DOWNSLOPE FLOW AND
SHEARING ALOFT SHOULD ACT TO DECREASE PRECIPITATION WITH TIME ACROSS
CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND. TIMING WAS ALSO
ADJUSTED BASED ON FASTER RADAR TRENDS. UPDATED FORECAST IS
CONSISTENT WITH TRENDS INDICATED BY THE 15Z SHORT RANGE ENSEMBLES AS
WELL.
WIND SHIFT WILL OCCUR WITH THE COLD FRONTAL PASSAGE OVERNIGHT FROM
NORTHWEST TO SOUTHEAST ACROSS THE REGION. TIMING OF THE COLD FRONT
AND MEAGER COLD AIR BEHIND THE BOUNDARY SHOULD PREVENT TEMPERATURES
FROM FALLING TOO QUICKLY.
WILL HAVE TO MONITOR FOR POSSIBLE FOG FORMATION OVERNIGHT AS
MOISTURE INCREASES ATOP THE SNOW/SLEET PACK.
&&
.AVIATION...
CEILINGS AND VISIBILITIES WILL DETERIORATE MOST LIKELY INTO TO MVFR
FLIGHT CATEGORY THIS EVENING AND EARLY TONIGHT AS AN AREA OF RAIN
MOVES INTO THE REGION. A COLD FRONTAL PASSAGE WILL TAKE PLACE FROM
THE NORTHWEST DURING THE MIDDLE OF THE NIGHT...PROVIDING A WIND
SHIFT TO THE NORTHWEST.
&&
.MARINE...
12Z MET/18Z MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS
DECREASE TO ABOUT 10KT THROUGH THE NIGHT. PROXIMITY 12Z GFS/18Z NAM
BUFKIT FORECAST SOUNDINGS INDICATE A 17-24KT WIND GUST POTENTIAL
NEAR KNHK THROUGH THE NIGHT. ICE COVERAGE HAS DECREASED DUE TO THE
WARMER TEMPERATURES.
&&
.TIDES...
CURRENT TIDAL DEPARTURES ARE A HALF FOOT BELOW ASTRONOMICAL
PREDICTIONS. THE LUNAR CYCLE IS WAXING TOWARD A QUARTER MOON (14
PERCENT FULL). THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND
THE NOAA EXTRATROPICAL STORM SURGE MODEL INDICATE DEPARTURES MAY
INCREASE TO A FOOT BELOW PREDICTED VALUES BY THE MORNING.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR
ANZ534-537.
&&
SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
415 PM EST MON FEB 19 2007
.DISCUSSION...
.SYNOPSIS...
ZONAL FLOW PRESENT ALOFT SUPPORTS QUICK MOVING SHORTWAVES AND SFC
LOWS TRACKING WEST TO EAST ACROSS SOUTHERN CANADA INTO NORTHERN UPR
GREAT LAKES. AT LEAST THAT IS THE THEME THROUGH MOST OF THE UPCOMING
WEEK. MUCH MORE AMPLIFIED UPR AIR PATTERN DEVELOPS BY NEXT WEEKEND
AS DEEP TROUGH PRESENTLY OVR GULF OF ALASKA (00Z AIRCRAFT REPORT OF
200KT AT H3) DIGS TOWARD FAR SW CONUS FRI AND LIFTS TOWARD THE GREAT
LAKES THIS UPCOMING WEEKEND. EXACT TRACK OF SFC LOW IS STILL IN
QUESTION AND WILL HAVE LARGE IMPACT ON PCPN TYPE...BUT THERE IS
CONSENSUS THAT SYSTEM WILL LEAD TO THE FIRST LARGE SCALE PCPN EVENT
OVR UPR LAKES IN QUITE A WHILE. MORE ON THIS SYSTEM LATER. SHORTWAVE
IN NORTHERN STREAM IS MOVING ACROSS LK SUPERIOR ATTM WITH ASSOCIATED
SFC LOW OVR FAR NORTHERN LK SUPERIOR. DESPITE A FAIRLY LOW PRES OF
29.3 INCHES OR 994MB...NOT MUCH IN WAY OF PCPN TODAY OVR UPR MI.
WIDESPREAD PCPN STAYED WELL TO NORTH OVR MANITOBA AND ONTARIO ALONG
THE WARM FRONT. EVEN A COUPLE OF 1/4SM +SN REPORTS EARLY AFTN JUST
NORTH OF LK SUPERIOR. TO THE SOUTH IN THE WARM SECTOR OVR UPR MI...
DRY AIR BLO H9 AND ABOVE H85 HAS RESULTED IN A PERSISTENT BKN-OVC
STRATUS DECK. A FEW LIGHT LK EFFECT SNOW SHOWERS ARE NOTED CLOSE TO
LK MI WITH THE S/SW WINDS AND LINGERING INSTABILITY. GOOD DISPLAY OF
SUNSHINE ALLOWED TEMPS TO ECLIPSE THE FREEZING MARK AT A FEW SOUTH
CENTRAL UPR MI SITES...INCLUDING 36 DEGREES THUS FAR AT MENOMINEE.
CLOUDS AND PERSISTENT COOLER LOW LEVEL COLD AIR HAS KEPT THE ERN
PORTION OF UPR MI STUCK IN THE LWR 20S.
&&
.SHORT TERM (TONIGHT AND TUESDAY)...
GENERALLY TRANQUIL WX EXPECTED NEXT 24 HRS. LOW PRES PRESSES
STEADILY INTO QUEBEC LATE TONIGHT WITH SLIGHTLY COOLER AIR PUSHING
ACROSS LK SUPERIOR ON W-NW WINDS. GFS/NAM SOUNDINGS AT CMX/STDM4
SHOW INVERSION HEIGHTS NEARING 850MB BY 12Z WITH TEMPS AT INVERSION
TOP AROUND -10C. PRETTY MARGINAL FOR LES. NO HELP FM ANY LARGE SCALE
FORCING EITHER AS THERE IS ONLY Q-VECTOR DIVERGENCE AND DRY AIR
ABOVE 850MB. EXTENSIVE ICE COVERAGE OVR WESTERN LK SUPERIOR PER
MODIS IMAGE FM YDY AFTN SHOULD ALSO INHIBIT LES. IN REALITY...ABOUT
THE ONLY THING GOING FOR LES IS FAIRLY MOIST MIXED LAYER AS UNLIKE
THE LAST MONTH...THIS IS DEFINETELY NOT DRY/ARCTIC AIR ADVECTING
ACROSS THE LAKE. HAVE ONLY FLURRIES OVR NW CWA DUE TO LIMITING
FACTORS BUT DID KEEP SOME SNOW SHOWERS IN GRIDS OVR NORTHEAST
CWA LATE TONIGHT INTO TUE AS NW WINDS ALLOW FOR LONGER OVER WATER
AND LESS ICE COVERED FETCH. MARGINAL SETUP AND POOR SNOW GROWTH
RESULT IN LITTLE IF ANY ACCUM. SHORTWAVE OVR SW SASKATCHEWAN MAKES
RUN AT UPR LAKES LATE TUE. MOISTURE REMAINS LIMITED SO NOT EXPECTING
ANY SYNOPTIC PCPN DESPITE WEAK ISENTROPIC LIFT. IF IT WAS A BIT
COOLER AT H9-H85 LES WOULD LIKELY GET A BOOST OVR NW. BUT SINCE IT
IS ACTUALLY WARM ADVECTING SLIGHTLY DURING THIS PERIOD...WILL
JUST KEEP FLURRIES NORTHWEST AND LIGHT LES IN THE NORTHEAST. CLOUDS
SHOULD REMAIN LOCKED IN EVERYWHERE...AS LOWER LEVEL MOISTURE REMAINS
TRAPPED BLO INVERSION NEAR H85. WARMER GUIDANCE TEMPS PREFERRED
TONIGHT AS LOWER LEVEL COLD AIR ADVECTION IS WEAK AND UPSTREAM TEMPS
IN WAKE OF LOW PRES ARE STILL IN THE 20S/30S. H9 TEMPS CHANGE LITTLE
OVR MAJORITY OF AREA ON TUE SO EXPECT MAX TEMPS TO BE A FEW DEGREES
EITHER SIDE OF READINGS SEEN THIS AFTN.
&&
.LONG TERM...(TUE NIGHT THROUGH MON)
MAIN FCST CONCERNS TURN FROM NEXT CLIPPER SKIMMING THE UPPER GREAT
LAKES TO STORM SYSTEM FCST TO DEVELOP OVER THE CNTRL CONUS.
TUE NIGHT INTO WED...
12Z NAM/GFS PROGS SHOW AN ININITAL WEAK SHRTWV AND
ASSOCIATED 850-700 MB TROF MOVING THROUGH THAT IS NOT EXPECTED TO
PPODUCE ANY MORE THAN FLURRIES. THEN...INCREASING 280K-290K
ISENTROPIC LIFT WILL SPREAD ACRS THE CWA BTWN 06Z-18Z. WITH ONLY
MODERATE LIFT AND SINCE THE 280K LEVEL (900-800 MB LAYER) REMAINS
FAIRLY DRY...POPS WERE TAPERED FROM 40 TO 20 FROM NE TO SW. EXPECT
ANY ACCUMULATONS WILL REMAIN IN THE INCH OR LESS RANGE. WAA SHOULD
PUSH TEMPS WELL INTO THE 30S OVER MOST OF THE CWA WITH READINGS
CLOSE TO 40 POSSIBLE OVER THE SOUTH AND WEST IF ENOUGH SUNSHINE
DEVELOPS...PER 12Z NAM.
WED NIGHT INTO THU...
MODERATE 700-500 MB QVECTOR CONV WITH THE
SHRTWV COULD ALSO BRING SOME SNOW SHOWERS OR FLURRIES THROUGH THE
NORTH HALF OF THE AREA IN THE EVENING. COLD AIR FOR LES OVERNIGHT
INTO THU WILL BE MARGINAL WITH 850 MB TEMPS FCST INTO THE -10C TO
-12C RANGE BY 12Z/THU. HOWEVER...WITH CYCLONIC FLOW AND LINGERING
MOISTURE IN THE WAKE OF THE LOW...SOME LES OR LAKE ENHANCED SNOW
WILL STILL BE POSSIBLE. THE BEST CHANCE FOR ANY LIGHT ACCUMULATIONS
WILL BE OVER THE EAST WITH THE LONGER FETCH IN FLOW VEERING FROM WNW
TO NNW. SHARP PRES RISE OF 10-12 MB/6 HRS...PER GFS ALSO POINTS TO
POTENTIAL FOR GALES OVER THE LAKE AND STRONG WINDS FOR EXPOSED
HIGHER TERRAIN(KEWEENAW PENSINULA) AND SHORELINE AREAS.
FRI-MON...
THE GLOBAL MODELS AGREE THAT A SHRTWV EMERGING FROM THE SW
CONUS WILL LEAD TO THE DEVELOPMENT OF A CLOSE MID/UPPER LEVEL LOW
OVER THE PLAINS THAT WILL LIFT TOWARD THE UPPER MS VALLEY AND
EVENTUALLY THE WRN GREAT LAKES. WHILE DIFFERENCES IN THE DETAILS ARE
NOT AS PRONOUNCED AS IN EARLIER RUNS...SIGNFICANT DIFFERENCES
REMAIN. THE FCST WILL TOWARD A COMBINATION OF THE 00Z/12Z/19 ECMWF
IN LINE WITH THE HPC PREFERENCE. THE 12Z/19 GFS HAS TRENDED TOWARD
THIS SOLUTION AND BACKED AWAY FROM THE 06Z/19 FARTHER W SFC LOW
TRACK AND STRONG INFLUX OF WARM AIR BY SUN.
THE INTITIAL WAA SURGE OF MOISTURE WITH 290K-295K ISENTROPIC LIFT
SHOULD BEGIN TO AFFECT SW CWA BY LATE FRI AND SPREAD ACRS THE CWA
THROUGH SAT. THE SECOND AND STRONGER BATCH OF DYNAMICS WILL ARRIVE
TOWARD SUN AS THE MID/UPPER LEVEL LOW NEAR THE AREA. ALTHOUGH THE
12Z GFS MODEL FCST SNDGS SHOW THE TEMP PROFILE BLO 0C...SUPPORTING
SNOW...CANNOT RULE OUT THE POSSIBILITY THAT AN ELEVATED WARM LAYER
AND/OR ENOUGH SFC WARMING WILL MOVE MOVE IN BY SUN FOR FZRZ/RA/PL
CHANCES SUN AS INDICATED IN PREVIOUS RUNS. THE GFS ALSO OFTEN
UNDERPLAYS THE AMOUNT OF WARMING IN SUCH PATTERNS. HOWEVER...IF 12Z
MODEL TRENDS HOLD UP...THE BULD OF RAIN OR MIXED PCPN WOULD LIKELY
OCCUR S OF UPPER MI OR IN THE SRN PORTION OF THE CWA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
JLA(SHORT TERM)
JLB(LONG TERM)
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1058 AM EST MON FEB 19 2007
.UPDATE...12Z SURFACE ANALYSIS THIS MORNING HAS A SURFACE WARM FRONT
STRETCHED ACROSS NORTHERN LAKE HURON...THROUGH EASTERN UPPER
MICHIGAN...AND INTO SOUTHWESTERN ONTARIO. LIGHT SNOWS ASSOCIATED
WITH ISENTROPIC ASCENT ALONG THIS BOUNDARY ARE NOW PUSHING NORTH AND
EAST OF EASTERN UPPER MICHIGAN. A SECONDARY WARM FRONT IS LIFTING
NORTHWARD THROUGH SOUTHEASTERN MINNESOTA...NORTHERN ILLINOIS...BAND
INTO WESTERN INDIANA. VERY LITTLE IN THE WAY OF MOISTURE SEEN WITH
THE SECONDARY WARM FRONT TO THE SOUTH. JUST SOME HIGH TO MID LEVEL
CLOUDINESS. STRONG SOUTHERLY FLOW HAS DEVELOPED ACROSS THE AREA IN
RESPONSE TO THE TIGHTENING GRADIENT ON THE BACK SIDE OF THE SURFACE
RIDGE...NOW LOCATED ACROSS NEW ENGLAND. FORECAST ISSUES THIS
AFTERNOON STILL REVOLVE AROUND DRIZZLE/LIGHT SNOW POTENTIAL. SO FAR
THIS MORNING...CURRENT OBSERVATIONS TO THE WEST ARE NOT VERY
SUPPORTIVE OF ANY DRIZZLE. MATTER OF FACT...SKIES HAVE BEEN CLEARING
OUT ACROSS LOWER MICHIGAN. THE WIDESPREAD LOW CEILINGS DEPICTED BY
THE MODELS OVER THE PAST FEW DAYS ARE NOWHERE TO BE SEEN. THERE ARE
SOME LOWER CEILINGS...MAINLY ACROSS EXTREME NORTHERN WISCONSIN...AND
UPPER MICHIGAN. DULUTH...WHERE LOWER CEILINGS AND REDUCED
VISIBILITIES HAVE BEEN OCCURING...IS CURRENTLY REPORTING NO FREEZING
DRIZZLE OR LIGHT SNOW. MOISTURE DOES NOT APPEAR TO BE DEEP
ENOUGH...AS ACARS SOUNDINGS SHOW MOISTURE ONLY UP TO AROUND 900MB.
MODEL SOUNDINGS GET THE MOISTURE UP TO AROUND 800MB. THUS...MODEL
DATA IS NOT REALLY AGREEING WITH CURRENT OBSERVATIONS.
WITH THIS ALL SAID...WILL REMOVE MENTION OF FREEZING DRIZZLE FOR
THIS AFTERNOON AND TONIGHT ACROSS NORTHERN LOWER MICHIGAN. WILL KEEP
A CHANCE OF LIGHT SNOW IN EASTERN UPPER MICHIGAN TO ACCOUNT FOR
STRONG ISENTROPIC ASCENT AND FORCING WITH A WEAK SHORTWAVE IMPULSE
COMING THROUGH. LOWER LEVEL MOISTURE IS A BIT DEEPER IN THE NORTH AS
WELL...AS SUPPORTED BY THE LOWER CEILINGS ACROSS THE DLH AND MQT
AREAS. TEMPERATURES LOOK ON TRACK WITH THE CURRENT FORECAST...
TOPPING OUT GENERALLY IN THE UPPER 20S TO AROUND 30.
KAS
&&
.PREV DISCUSSION...ISSUED AT 443 AM EST MON FEB 19
DEEP UPPER TROUGH ACROSS THE EASTERN CONUS DURING THE WEEKEND
CONTINUING TO SLIDE TOWARD THE ATLANTIC...WITH A LESS AMPLIFIED
QUICK FLOW EMERGING OVER NOAM. SHORT WAVE MID LEVEL RIDGE BUILDING
ACROSS THE WESTERN GREAT LAKES THIS MORNING WHILE ASSOCIATED SHARP
SFC RIDGE AXIS ALREADY EAST OF THE STATE. UPSTREAM...MID LEVEL SHORT
WAVE NOTED NEAR LAKE WINNIPEG AND ASSOCIATED BROAD SFC LOW CENTERED
OVER THE DAKOTAS. FRONTOGENETIC FORCING WELL AHEAD OF THIS
APPROACHING CLIPPER SYSTEM HAS BEEN RAMPING UP THROUGHOUT THE NIGHT
ACROSS THE WESTERN GREAT LAKES WITH ABUNDANT MID/HIGH CLOUD COVER
NOW ACROSS MICHIGAN AND BAND OF MAINLY MID LEVEL RADAR RETURNS
(TELLTALE RING AROUND THE RADAR LOOK) OVER THE CWA. PER SFC OBS
NOTHING REACHING THE GROUND THUS FAR BUT BEST POSSIBILITIES OF SOME
LIGHT SNOW LOOKING TO BE ACROSS EASTERN UPPER MICHIGAN AND THE TIP
OF THE MITT COUNTIES.
FORECAST CONCERNS IN THE NEAR TERM REVOLVE AROUND SNOW CHANCES WITH
THE WARM ADVECTION FORCING TODAY...AND FREEZING DRIZZLE
POSSIBILITIES LATER IN THE DAY THROUGH TONIGHT.
TODAY AND TONIGHT...AFOREMENTIONED MID LEVEL WAVE AND ASSOCIATED SFC
LOW EXPECTED TO PASS THROUGH NRN MICHIGAN LATE THIS AFTERNOON AND
THIS EVENING...FOLLOWED BY A WEAK COLD FRONT MOVING THROUGH DURING
THE OVERNIGHT HOURS. STRONGEST FORCING WITH THIS SYSTEM LOOKING TO
BE ENTIRELY ON THE FRONT END WITH WARM ADVECTION SURGE MOVING
THROUGH THE REGION FROM NOW THROUGH MID AFTERNOON OR SO. HOWEVER...
GIVEN WEDGE OF DRY AIR BLO 800 MB DURING THIS TIME...NOT EXPECTING
VERY MUCH IN TERMS OF MEASURABLE SNOW. BEST SHOT LOOKING TO REMAIN
OVER THE NRN THIRD OF THE CWA WHERE SLIGHTLY BETTER MOISTURE AND
FORCING WILL COME TOGETHER.
NEXT ISSUE REVOLVES AROUND FREEZING DRIZZLE POSSIBILITIES. WITHIN
THE DEVELOPING STRONG WARM ADVECTION REGIME...NAM/GFS FORECAST
SOUNDINGS AND RH PROGS REMAIN ADAMANT SATURATING THE LOWER LAYERS
BLO 800 MB DURING THE AFTERNOON...PARTICULARLY OVER THE NRN HALF OF
THE CWA... WITH A THERMAL PROFILE WARMER THAN -10C ACROSS MOST OF
NRN LOWER MICHIGAN. FORECAST DATA CERTAINLY HAS A FREEZING DRIZZLE
LOOK ACROSS NRN LOWER MICHIGAN AND WILL MAINTAIN THIS IDEA FOR
NOW...ALTHOUGH LOOKING UPSTREAM NO REAL SIGN OF THIS AS OF YET. A
COLDER PROFILE TO THE NORTH SHOULD KEEP ANY PRECIP THAT FALLS AS
SNOW.
LATE TONIGHT THROUGH TUESDAY NIGHT...CLIPPER SYSTEM EXITS THE REGION
BY EARLY TUESDAY MORNING WITH HIGH PRESSURE...DRIER AND SLIGHTLY
COOLER LOW LEVEL AIR SPREADING INTO THE REGION. STILL JUST COLD
ENOUGH (850 MB TEMPS AROUND -12C) FOR SOME LIGHT SNOW SHOWER
POSSIBILITIES OFF LAKE SUPERIOR INTO THE EVENING BEFORE THE FLOW
BACKS AROUND IN ADVANCE OF YET ANOTHER CLIPPER SYSTEM FOR WEDNESDAY.
WEDNESDAY THROUGH FRIDAY...WITH OVERALL ZONAL FLOW ESTABLISHED
A MILDER STRETCH OF WEATHER LOOKING TO CONTINUE THROUGH THE
WEEK...BEFORE FLOW RE-AMPLIFICATION TAKES SHAPE TOWARD THE WEEKEND
AND POSSIBLY BRINGING A STRONG SRN STREAM STORM UP THROUGH THE GREAT
LAKES FOR THIS WEEKEND. UNTIL THEN...ANOTHER CLIPPER SYSTEM SLATED
TO PASS THROUGH NRN MICHIGAN WEDNESDAY INTO EARLY THURSDAY BRINGING
ANOTHER CHANCE FOR LIGHT SNOW MAINLY TO THE UPPER PENINSULA. HIGH
PRESSURE ESTABLISHES OVER THE REGION LATER THURSDAY THROUGH THE DAY
FRIDAY WITH DRY WEATHER ANTICIPATED. LATEST GFS SOLUTION SUGGESTS
WARM ADVECTION PRECIP (IN ADVANCE OF WEEKEND STORM) MAY DEVELOP INTO
PORTIONS OF LOWER MICHIGAN AS EARLY AS FRIDAY AFTERNOON. BUT THIS
FAR OUT MODELS ARE USUALLY FAST WITH SYSTEMS LIFTING OUT OF THE
PLAINS. STILL QUITE A BIT OF TIME TO REFINE THE DETAILS AND HAVE
MAINTAINED PRECIP CHANCES BEGINNING FRIDAY NIGHT ONWARD.
ADAM
&&
.APX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SEATTLE WA
845 AM PST MON FEB 19 2007
.SYNOPSIS...A PACIFIC WEATHER SYSTEM WILL BRING RAIN TODAY THROUGH
EARLY TUESDAY...AND HEAVY SNOW IN THE MOUNTAINS. THEN COOL MOIST
UNSTABLE AIR WILL PRODUCE UNSETTLED SHOWERY CONDITIONS FOR MUCH OF
THE REST OF THE WEEK.
&&
.SHORT TERM...PRECIPITATION HAS PRETTY MUCH SPREAD ACROSS THE ENTIRE
AREA. THE ONLY AREA WITHOUT ANY RAIN IS THE REGION DOWNWIND OF THE
OLYMPICS WHICH AT THE MOMENT IS THE AREA FROM PORT ANGELES AROUND
THE NORTHEAST PART OF THE PENINSULA AND SOUTH NEARLY TO BREMERTON.
AFTER THE WARM FRONT PASSES BY...THIS AREA WILL ROTATE CLOCKWISE
AROUND THE OLYMPICS AS THE WINDS ALOFT BECOME MORE WESTERLY RATHER
THAN SOUTHWEST. FOR THE REMAINDER OF THE AREA FAIRLY STEADY RAIN
THROUGH TONIGHT...LIGHTER NEAR THE OLYMPIC HOLE AND HEAVIER OUTSIDE
THIS REGION.
THE BIGGER STORY WITH THIS SYSTEM WILL BE THE HEAVY SNOW THAT WILL
FALL OVER THE MOUNTAINS OVER THE NEXT 24 HOURS OR SO. SO FAR THE
MAIN MOUNTAIN GAGES ARE PICKING UP AROUND A HALF INCH OF SNOW PER
HOUR BUT THIS RATE WILL PICK UP LATER TODAY WITH MODERATE TO HEAVY
SNOW CONTINUING THROUGH TONIGHT. THE STEADY PRECIP WILL CONTINUE
UNTIL THE COLD FRONT SAGS SOUTH OF THE AREA TUESDAY. MODELS
CONTINUE TO PUNCH OUT 2-3 INCHES LIQUID FOR THE MOUNTAINS WITH A
COUPLE OF MESOSCALE RUNS INDICATING LOCALLY HIGHER AMOUNTS FOR STORM
TOTALS. THIS LOOKS REASONABLE GIVEN THE PERSISTENT AND FAIRLY
STRONG WESTERLY FLOW...WHICH IS ALSO PLENTY MOIST AND CONDITIONALLY
UNSTABLE.
THUS THE CURRENT WARNING AND FORECAST LOOKS GOOD WITH THE IDEA OF A
SIGNIFICANT SNOWFALL FOR THE MOUNTAINS. STORM TOTAL AMOUNTS WILL
RANGE FROM 2-4 FEET DEPENDING ON LOCATION (MORE NORTH) AND EXPOSURE
(MORE WITH WESTERLY EXPOSURE). CURRENT SNOW LEVELS BASED ON ACARS
DATA STILL SHOWS ABOUT 2500 FEET AND THIS SHOULD ONLY RISE TO AROUND
3000 FEET IN THE CASCADES AND MAYBE TO AROUND 3500 FEET IN THE
OLYMPICS.
THIS HEAVY SNOW COMBINED WITH WINDY CONDITIONS WILL MAKE FOR SOME
NASTY CONDITIONS IN THE MOUNTAINS OVER THE NEXT 24-30 HOURS. THERE
IS ALSO THE INCREASED POTENTIAL FOR AVALANCHES AS THIS WILL BE A
SIGNIFICANT AMOUNT OF SNOW ON TOP OF WHAT BASICALLY AMOUNTS TO A
HARD SLAB OF SNOW/ICE THAT IS ALREADY THERE. FOR MORE ON THIS
PLEASE REFER TO THE AVALANCHE CENTER FORECAST AT HTTP://NWAC.US
AT LEAST WE WILL BE ADDING TO THE SUMMER WATER SNOWPACK. AS OF THE
15TH THE SNOW PACK WAS NEAR NORMAL LEVELS...BUT TRENDING UNDER THE
NORMAL LINE OVERALL. THIS WEEKS SNOWFALL WILL HELP THAT SITUATION.
FORECAST LOOKS GREAT AND AT THIS POINT SEE NO REASON TO FOOL WITH
IT. NO UPDATES PLANNED. CERNIGLIA
.LONG TERM...FROM PREVIOUS DISCUSSION...THE EXTENDED PERIOD BEGINS
WITH THE UPPER LEVEL TROUGH ALONG THE WEST COAST DIGGING FURTHER
SOUTHWARD AND CONDITIONS REMAINING COOL AND UNSETTLED. WEAK UPPER
LEVEL RIDGING MAY LEAD TO A BRIEF MOSTLY DRY DAY ON FRIDAY. THE
EXTENDED MODELS HAVE BEEN PRETTY CONSISTENT OF LATE WITH ANOTHER
SIGNIFICANT FRONT APPROACHING THE COAST LATE FRIDAY INTO SATURDAY.
THE UPCOMING WEEKEND IS LOOKING COOL AND SHOWERY WITH ANOTHER COLD
TROUGH OVER THE REGION. 27
&&
.AVIATION...WARM FRONT WILL MOVE THRU THE AREA BY 21Z THIS AFTN WITH
COLD FRONT PUSHING SE ACROSS THE AREA 12Z-18Z TIME FRAME TUE. LIGHT
TO MODERATE PRECIPITATION WILL CONTINUE FOR MUCH OF THE NEXT 24
HOURS...BUT STRONG WSW FLOW ALOFT WILL INTERACT WITH THE TERRAIN
KEEPING PRECIPITATION LIGHT N OF KSEA. GUSTY S WINDS ON THE COAST
WITH BARRIER JET AND IN THE PUGET SOUND LOWLANDS AS MESOLOW BECOMES
ESTABLISHED NE OF OLYMPICS UNTIL FRONTAL PASSAGE TUE MORNING. CIGS
GENERALLY 010-015 THRU THE PERIOD...BUT LOCALLY LOWER IN HEAVIER
PRECIPITATION.
AT KSEA...STEADY -RA WITH CIGS DROPPING TO BKN015 22Z-00Z THIS AFTN.
LOWEST VIS 06Z-14Z TIME FRAME AHEAD OF INCOMING CDFNT. WIND AT KSEA
19012KT...INCRG TO 19018G25KT 06Z-15Z TIME FRAME...THEN DROPPING OFF
TO 20010KT BEHIND CDFNT. ALBRECHT
$$
.SEW WATCHES/WARNINGS/ADVISORIES...
.GALE WARNING COAST.
.SMALL CRAFT ADVISORY REMAINING WATERS.
.SMALL CRAFT ADVISORY GRAYS HARBOR FOR ROUGH BAR CONDITIONS.
.WINTER STORM WARNING FOR THE OLYMPICS AND THE CASCADES.
$$
WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
400 AM CST MON FEB 19 2007
.SHORT TERM...TODAY THROUGH TUESDAY. STRONG LOW LEVEL JET IS BRINGING
MUCH MILDER AIR NORTHWARD THROUGH THE PLAINS STATES EARLY TODAY.
AIRCRAFT SOUNDINGS FROM MSP/MCI/RFD SHOW AS MUCH AS 55 KNOTS BETWEEN 850
AND 925MB. SURFACE TEMPERATURES HAD CLIMBED INTO THE 30S IN WESTERN IOWA
AND SOUTHWEST MINNESOTA AS OF 330 AM. THE ATMOSPHERE IS QUITE DRY AND
THERE HAS BEEN NO REPORTS OF LIGHT SNOW OR FREEZING DRIZZLE FROM THE
CLOUDS OVER NORTHERN WISCONSIN SO FAR. WILL LEAVE A SLIGHT CHANCE OF
SNOW FLURRIES OR FREEZING DRIZZLE IN THE NORTH AS THE AIR MOISTENS
FURTHER TODAY. TIMING OF LOW CLOUDS IS DIFFICULT...AS LOW LEVELS QUITE
DRY TO OUR SOUTH OVER ILLINOIS. IT MAY TAKE UNTIL THE AFTERNOON OR
EVENING HOURS. TEMPERATURES WILL PROBABLY RISE TO NEAR FREEZING IN THE
SOUTHERN PART OF THE FORECAST AREA WITH UPPER 20S IN THE NORTH. WEAK
COLD ADVECTION ARRIVES LATE TONIGHT AND TUESDAY TO TEMPER THE WARM UP...
WITH HIGH TEMPERATURES CLOSE TO WHAT WE HAVE TODAY.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT SUNDAY.
QUIET PATTERN EXPECTED THROUGH THURSDAY AS HIGH PRESSURE REMAINS
OVER THE AREA. TEMPERATURES SHOULD BE NEAR OR EVEN SLIGHTLY ABOVE
NORMAL. TRENDED DOWNWARD A LITTLE IN THE SKY COVER GRIDS AND MADE
MINOR ADJUSTMENTS TO MATCH UP WITH SURROUNDING OFFICES.
ATTENTION TURNS TO THE UPCOMING STORM THIS WEEKEND WITH A PROLONGED
PERIOD OF PRECIPITATION FRIDAY NIGHT INTO SUNDAY. SYSTEM EJECTING
OUT OF THE PLAINS APPEARS TO BE A LITTLE SLOWER ON THE CANADIAN/ECMWF
THAN THE GFS. WITH CANADIAN HIGH TO THE NORTHEAST...ONSET OF
PRECIPITATION SHOULD BE SOMEWHAT SLOW THAN WHAT THE GFS IS SUGGEST.
AS EXPECTED LAST NIGHT...GFS 850MB TEMPERATURES ARE COOLER THAN LAST
NIGHTS RUN AND LOOKS MORE LIKE THE 00Z ECMWF RUN LAST NIGHT.
WITH EVAPORATIVE COOLING TAKING PLACE...PRECIPITATION SHOULD START
AS SNOW EVERYWHERE THEN BECOME MIXED WITH OR CHANGE OVER TO FREEZING
RAIN OR SLEET. THE 00Z GFS TONIGHT TRENDED FURTHER SOUTH WITH THE
SURFACE LOW AND LOOKED MORE LIKE THE 00Z ECMWF FROM THE LAST NIGHT.
THE 00Z ECMWF TONIGHT SHIFTED THE SURFACE LOW TRACK FURTHER WEST
AND IS NOW WEST OF GREEN BAY ON SUNDAY. WITH THIS MUCH UNCERTAINTY
IN THE SURFACE LOW TRACK AND THE LOW LEVEL THERMAL PROFILE...
CURRENT GRIDS/TEXT PRODUCTS WILL SUFFICE UNTIL WE GET CLOSER TO
THE EVENT.
DID LOOK AT THE 00Z GFS QPF/SNOW FIELDS AND THE GFS BUFKIT SOUNDINGS...
THE GFS QPF TOTALS ARE DOWN RIGHT SCARY. THE GFS WAS GIVING CLOSE TO
TWO INCHES OF QPF AT RHINELANDER...WHICH WOULD POSSIBLY MEAN OVER A
FOOT OF SNOW ALTHOUGH SLEET COULD MIX IN AT TIMES. AT GREEN BAY...
THE GFS BUFKIT SOUNDING INDICATED OVER AN INCH OF FREEZING RAIN AND
SLEET AFTER A PERIOD OF SEVERAL INCHES OF SNOW. SOMETHING TO WATCH
UNTIL THE WRF MODEL CAN CATCH ONTO SYSTEM FOR THE LOW LEVEL THERMAL
AND MOISTURE PROFILES. STAY TUNED!
&&
.AVIATION...ISENTROPIC LIFT ACROSS WESTERN WISCONSIN AND MINNESOTA WILL
GRADUALLY SPREAD MVFR CEILINGS ACROSS THE FORECAST AREA FROM WEST TO
EAST THIS EVENING AND OVERNIGHT. A BRIEF PERIOD OF 5000 TO 6000 FT
CEILINGS CAN BE EXPECTED BEFORE THE LOWER CLOUDS ARRIVE. WINDS SHOULD BE
LIGHT EARLY...BUT THEN INCREASE LATER IN THE NIGHT AS A SURFACE RIDGE
PASSES EAST OF THE AREA AND WINDS SHIFT TO THE SOUTH. CONFIDENCE IN PCPN
FORECAST...BOTH TYPE AND CHANCES...DURING THE LAST 6 TO 9 HOURS OF THE
TAFS IS RELATIVELY LOW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
RDM/ECKBERG
WEATHER.GOV/GREENBAY
|