FORECAST DISCUSSION
.SYNOPSIS...
HIGH PRESSURE ALOFT WILL BUILD ACROSS THE DESERT SOUTHWEST OVER THE
NEXT SEVERAL DAYS. THIS WILL RESULT IN GRADUALLY WARMER TEMPERATURES
...ALONG WITH MOSTLY CLEAR SKIES THROUGH THE MIDDLE OF NEXT WEEK.
ANOTHER LOW PRESSURE SYSTEM FROM THE GULF OF ALASKA IS EXPECTED TO
BRING A RETURN TO COOLER WEATHER AND A SLIGHT CHANCE OF SHOWERS LATE
THIS COMING WEEK INTO THE WEEKEND.
&&
.SHORT TERM...
TODAY THROUGH TUESDAY...
LATEST SAT IMAGERY SHOWS A SIGNIFICANTLY DRIER AIRMASS IN
PLACE OVER SOUTHEAST CA AND MUCH OF ARIZONA. SURFACE DEW POINTS ARE
IN THE UPPER 30S MOST PLACES...DOWN 10-20 DEG ACROSS THE CWA FROM
THIS TIME YESTERDAY. NORMALLY AFTER A SIGNIFICANT RAIN EVENT LIKE
THE ONE FRI/SAT...FOG WOULD BE A MAJOR CONCERN THE MORNING AFTER
CLEARING. HOWEVER...GIVEN THE DRIER AIRMASS IN PLACE...IN ADDITION
TO THE STRONG SOUTHWESTERLY WINDS SATURDAY (WHICH HELPED DRY THE
SURFACE SOILS)...WIDESPREAD DENSE FOG IS NOT A MAJOR CONCERN THIS
MORNING. HOWEVER...ACROSS THE COOLEST DESERT LOCALES (LA
PAZ...YUMA...AND PORTIONS OF NORTHWESTERN MARICOPA COUNTY) WE COULD
SEE PATCHY FOG AS THE MORNING LOW TEMPS DIP INTO THE MID 30S. PATCHY
FOG IS ALSO EXPECTED ACROSS THE HIGHER TERRAIN TO THE EAST OF THE
VALLEY (ZONE 24) WHERE TEMPS ARE CURRENTLY IN LOW 40S TO UPPER 30S.
BY 8-9 AM...ANY FOG THAT DEVELOPS ACROSS THE CWA SHOULD BURN OFF FOR
A SUNNY/MOSTLY SUNNY DAY WITH NEAR CLIMO AFTERNOON HIGHS (SIMILAR TO
SATURDAY HIGHS).
STARTING MONDAY...HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST...
FOR INCREASING HEIGHTS AND A WARMING TREND. HIGHS ACROSS THE DESERT
FLOORS WILL WARM BACK INTO THE MID TO UPPER 70S BY TUESDAY...UNDER
CONTINUED CLEAR/MOSTLY CLEAR SKIES AND LIGHT WINDS.
&&
.LONG TERM...
TUESDAY NIGHT THROUGH SATURDAY...
HIGH PRESSURE WILL CONTINUE OVER THE SOUTHWEST THROUGH TUESDAY
NIGHT...WHERE THEN A SERIES OF WEATHER SYSTEMS WILL MOVE THROUGH THE
WESTERN CONUS. THE FIRST SYSTEM IS PROGGED TO MOVE ONSHORE THE PAC
NW EARLY WEDNESDAY...THEN THROUGH IDAHO AND INTO THE ROCKIES BY
THURSDAY. THIS FIRST DISTURBANCE WILL SUPPRESS THE HIGH PRESSURE
RIDGE OVER THE SOUTHWESTERN STATES...WITH 500MB HEIGHTS DROPPING
FROM 5888 00 UTC MON (TUE AFTN) TO 5720 BY 00 UTC FRIDAY (THU AFTN).
FCST CALLS FOR A COOLING TREND TO BEGIN MID WEEK...WITH HIGHS
COOLING INTO THE LOW 70S BY THU. MEANWHILE...ANOTHER PAC LOW
PRESSURE SYSTEM WILL DIG SOUTHWARD OFF THE WEST COAST...BEFORE
CLOSING OFF BY THE WEEKEND. WITH THE EXCEPTION OF THE 06 UTC GFS40
OPERATION RUN FROM LAST NIGHT (WHICH BRINGS THE LOW DOWN THE CA
COAST AND NEVER DOES CLOSE IT OFF)...THE MED RANGE MODELS (INCLUDING
THE GFS 500MB ENSEMBLE MEAN) ALL DEPICT A SIMILAR SOLUTION OF A
CUT-OFF LOW SOMEWHERE OFF THE SOUTHERN CA/BAJA COAST THIS WEEKEND.
AHEAD OF THE LOW...WE SHOULD SEE A DECENT INFLUX OF SUBTROPICAL
MOISTURE MOVING NORTHWARD THROUGH THE STATE STARTING FRIDAY...WITH
1000-700 MB MIXING RATIOS OVER THE SOUTH-CENTRAL DESERTS INCREASING
FROM AROUND 2 G/KG TUE TO OVER 6 K/KG BY FRI AFTERNOON. THE MOISTURE
FLUX WILL CONTINUE INTO THE WEEKEND...AHEAD OF THE DEVELOPING CLOSED
LOW. CURRENT FORECAST CALLS FOR A SLIGHT CHANCE FOR SHOWERS
BEGINNING OUT WEST AS EARLY AS THU NIGHT...SPREADING OVER THE ENTIRE
CWA FRIDAY INTO THE WEEKEND. GIVEN THE FINE PERFORMANCE OF THE GFS
WITH THIS PAST RAIN EVENT (NO SARCASM INTENDED...IT PRETTY MUCH
NAILED IT FOR OUR CWA AT 4-5 DAYS OUT)...WE`RE INCLINED TO BUY INTO
THE IDEA OF ANOTHER WET WEEKEND AHEAD.
&&
.AVIATION...
DECEMBER 2 1440 GMT (DECEMBER 2 0740 MST)
WITH THERMAL INVERSIONS ACROSS THE VALLEY THIS MORNING FROM THE
SURFACE UP TO 2 KFT AND ALSO FROM ABOUT 6-10 KFT (PER ACARS
SOUNDINGS)...THERE MAY BE REDUCTIONS TO SLANT-WISE VISIBILITY DUE TO
ELEVATED HAZE AT KPHX/ KIWA THROUGH 18 UTC. VISIBILITY WILL IMPROVE
THIS AFTERNOON AS THE BOUNDARY LAYER MIXES OUT...POSSIBLY
DETERIORATING AGAIN LATE THIS AFTERNOON AROUND SUNSET DUE TO THE LOW
SUN ANGLE.
PREVIOUS DISCUSSION...
WITH LIGHT WINDS AND CLEAR SKIES...BIGGEST AVIATION
CONCERN WILL BE THE POTENTIAL FOR EARLY MORNING FOG. DRY ADVECTION
CONTINUES IN THE LOWER LEVELS SO IT IS NOT REALLY PRACTICAL TO USE
THE UPS METHOD (AFTERNOON CROSSOVER TEMP) TO ASSESS THE LIKELIHOOD
OF FOG. DEWPOINT DEPRESSION AT SKY HARBOR EARLIER THIS MORNING WAS
15 DEG F...SO THE POTENTIAL FOR ANY REDUCTIONS IN VSBY IS WANING
THERE. ELSEWHERE...LATEST RUC PROFILES SUGGEST ENOUGH DECOUPLING
WILL TAKE PLACE JUST BEFORE SUNRISE TO PRODUCE A BRIEF PERIOD OF
MVFR BR AT YUM...BLH AND IPL. OTHERWISE...EXPECT MAINLY CLEAR SKIES
AND LIGHT WINDS THROUGH THE REMAINDER OF THE WEEKEND.
AVIATION DISCUSSION IS NOT UPDATED FOR AMENDED TAFS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT
WEATHER.GOV/PHOENIX
SHORT TERM...WANEK
LONG TERM...WANEK
AVIATION...P ROGERS/HIRSCH
AREA FORECAST DISCUSSION
NWS RENO NV
735 PM PST MON DEC 3 2007
.UPDATE...
WINDS ACROSS THE NORTHERN PORTION OF THE CWA ARE DIMINISHING PER
LATEST MESONET OBS...THEREFORE WILL ALLOW HW.W TO EXPIRE ON SCHEDULE
AT 8 PM PST. HOWEVER GIVEN 700MB WINDS ON THE ORDER OF 60KTS+
THROUGH THE OVERNIGHT HOURS...RIDGE TOPS WILL CONTINUE TO SEE STRONG
GUSTS AS VALLEYS DIMINISH. WILL CONTINUE WI.Y FOR THE RENO/TAHOE
AREA AS NORMALLY WIND PRONE AREAS SUCH AS GALENA CONTINUE TO GUST
NEAR 50 MPH. RECENT AIRCRAFT DATA INDICATE 700MB WINDS BETWEEN RNO
AND SAC OF AROUND 50KTS.
THUS FAR AREAS IN NEAR FORT BIDWELL AND IN LASSEN COUNTY HAVE SEEN
AT LEAST A FEW HUNDREDTHS OF RAIN TONIGHT. REGARDING PRECIP COVERAGE
TONIGHT...WILL EXPAND HIGHER POPS EASTWARD INTO EASTERN LASSEN AND
NRN/CNTRL WASHOE COUNTIES BASED ON RADAR TRENDS AND RUC FCSTS OF
SLIGHT WEAKENING IN POTENTIAL STABILITY BETWEEN 700-500MB ENHANCING
(AT LEAST TEMPORARILY) SPILL-OVER POTENTIAL. POOL OF WEAKENED
STABILITY MAY DROP FAR ENOUGH SOUTH OVERNIGHT TO ALLOW SOME SLIGHT
SPILL-OVER NEAR RENO AREA...BUT DEPTH OF MOISTURE FCST TO THIN BY
THEN. WILL MONITOR AND CONSIDER ADDING SOME LOW CHC POPS TO RENO
AREA LATER.
UPDATED PRODUCTS OUT BY 8 PM PST.
CS
&&
.SHORT TERM...
WINDS MIXED DOWN TO THE VALLEY FLOOR IN THE RENO AREA BETWEEN 10 AND
1030 AM...AND TEMPS JUMPED ABOUT 15 DEGREES DURING THAT TIME. THE
WIND ADVISORIES AND WARNINGS WILL CONTINUE THRU THEIR POSTED VALID
TIMES. GUSTS HAVE MAINLY BEEN BELOW WARNING CRITERIA SO FAR BUT WITH
THE APPROACH OF THE PRECIP BAND BY EARLY EVENING...THE WARNING AREAS
COULD STILL RECEIVE A SHORT PERIOD OF HIGH WINDS AS PRECIP LOADING
ATTEMPTS TO DRIVE SOME DOWNWARD MOMENTUM OF THE 65-75 KT WINDS
EXPECTED AT 700 MB.
PRECIP BAND ASSOCIATED WITH THE TROF PASSAGE WILL ENTER NERN CA THIS
EVENING AND PARTS OF WRN LASSEN COUNTY COULD SEE A DECENT AMOUNT OF
RAIN OF 0.25 TO 0.5 INCH...BUT AS THIS BAND PUSHES SOUTH TOWARD THE
TAHOE BASIN IT LOSES MUCH OF ITS UPPER LEVEL SUPPORT. ON TUESDAY...
SOME LINGERING SHOWERS OR A SMALL BAND OF MAINLY LIGHT RAIN WILL
REACH THE LOWER ELEVATIONS OF WRN NV BY MID-LATE MORNING AND WORK
THEIR WAY SOUTH TO THE MINERAL AND MONO ZONES DURING THE AFTERNOON.
WITH FREEZING LEVELS AT OR ABOVE 12000 FT MSL THRU TUESDAY...PRECIP
WILL BE IN THE FORM OF RAIN AT ALL SIGNIFICANT ELEVATIONS AND
PASSES. TEMPS WILL REMAIN WELL ABOVE NORMAL BUT NOT AS WARM AS TODAY
AS MIXING BECOMES LESS OPTIMAL AND MORE CLOUD COVER WILL BE PRESENT.
MOST AREAS WILL REMAIN DRY TUESDAY NIGHT THROUGH THURSDAY MORNING.
ZONAL FLOW OVER THE REGION WITH WEAK SHORTWAVE BRUSHING ACROSS THE
NWRN US WILL KEEP MID-HIGH LEVEL CLOUDS OVER MOST AREAS...BUT
MEASURABLE PRECIP IS UNLIKELY AS THE GUIDANCE CONSENSUS IS TRACKING
THIS SHORTWAVE FARTHER NORTH THAN PREVIOUS RUNS.
FOR THURSDAY-THURS NIGHT...THE NEXT STORM APPROACHING CA MAY BE THE
FIRST SIGNIFICANT SNOW EVENT OF THE SEASON FOR THE SIERRA...WITH
POSSIBLY SOME MEASURABLE SNOW IN LOWER ELEVATIONS OF WRN NV-ERN CA
AS WELL. THE TRACK OF THIS STORM IS THE BIG UNCERTAINTY AS THIS
SYSTEM COULD POTENTIALLY STAY TOO FAR OFFSHORE TO GET THE BEST
PRECIP TO THE SIERRA. THE 18Z GFS AND THE 12Z ECMWF HAD A MORE
OFFSHORE TRACK IN COMPARISON TO THEIR PREVIOUS RUNS. THE 12Z
CANADIAN AND UKMET FAVORED A MORE INLAND TRACK ACROSS CNTRL-SRN CA.
EVEN WITH THE FARTHER WEST TRACK DEPICTED BY THE 18Z GFS...A DECENT
SNOW COULD STILL OCCUR IN THE SIERRA WITH THIS MODEL RUN PRODUCING
UP TO 2 INCHES OF QPF ALONG THE CREST IN MONO COUNTY AND ABOUT 1
INCH WEST OF TAHOE SO LIKELY POPS WILL BE MAINTAINED IN THESE AREAS
FOR THURS NIGHT. THE PRECIP TYPE IN THE LOWER ELEVATIONS WOULD ALSO
BE HIGHLY DEPENDENT ON THE STORM TRACK...AND WITH GUIDANCE TRENDING
FARTHER WEST AND OFFSHORE...PRECIP IN THE LOWER VALLEYS IS MORE
LIKELY TO BE RAIN WITH SNOW POSSIBLY MIXING IN AT TIMES WHEN HEAVIER
PRECIP BANDS PASS THROUGH. FOR THIS FORECAST...THE PRELIMINARY SNOW
LEVELS WILL RANGE FROM 5000-5500 FT ON THURS NIGHT. MJD
.LONG TERM...FRIDAY THROUGH MONDAY...
THE POTENT UPPER LOW CONTINUES PASSING OVER CENTRAL AND SOUTHERN
CALIFORNIA FRIDAY WITH THE COLD CORE ALOFT BRINGING UNSTABLE
CONDITIONS. THIS WILL HELP BRING CONVECTIVE ENHANCEMENT OF ANY
ORGANIZED PRECIP AND SHOWERS TO ALL OTHER AREAS. THERE IS ALSO THE
POTENTIAL FOR A FEW LIGHTNING STRIKES UNDER THE CORE HOWEVER KEPT
THE MENTION OUT OF THE FORECAST FOR NOW AS BEST LOCATION IS STILL
UNCERTAIN. EVEN IF THE SYSTEM DOES TRACK FURTHER TO THE SOUTH AS
MODELS HAVE BEEN HINTING AT...THE COLD AND UNSTABLE AIRMASS WOULD
STILL BRING NUMEROUS SHOWERS TO AT LEAST THE SRN HALF OF THE
CWA...SO KEPT WITH HIGH POPS THERE.
THE LOW SLOWLY MOVES SOUTH AND EAST OF THE AREA SATURDAY MORNING
WITH ANY LINGERING SHOWERS TAPERING OFF. HIGH PRESSURE BUILDS OVER
THE WEST COAST SUNDAY PUSHING ANY PASSING SHORTWAVES NORTH OF THE
AREA. THE GFS BUILDS THE RIDGE A LITTLE FURTHER TO THE WEST WITH THE
POSSIBILITY FOR SOME INSIDE SLIDER-LIKE SHORTWAVES TO DIG OVER
NEVADA IN NLY FLOW ALOFT. THERE`S NOT MUCH SUPPORT FOR THIS FROM
OTHER MODELS BUT IT IS WORTHY OF SLIGHT CHANCE POPS OVER THE NRN
ZONES SUNDAY NIGHT AND MONDAY. JORDAN
&&
.AVIATION...
STRONG WINDS AND LOW LEVEL WIND SHEAR ARE THE MAIN CONCERN THROUGH
THIS EVENING. SOUTH WINDS WITH GUSTS AROUND 35 KTS HAVE BECOME
FAIRLY WIDESPREAD OVER THE AREA AND WILL CONTINUE THROUGH ABOUT 06Z.
BASED ON RECENT PIREPS AND NAM FORECAST SOUNDINGS...HAVE AMENDED
KRNO TAF TO ADD LLWS. WIND SPEEDS TO NEAR 45KTS POSSIBLE DOWN TO
2KFT AGL THROUGH ABOUT 4Z...THOUGH IT MAY CONTINUE LATER...WILL
MONITOR.
OTHERWISE VFR CONDITIONS WILL CONTINUE THIS EVENING. A BAND OF LOWER
CEILINGS AND SHOWERS WILL TRACK SOUTH DOWN THE SIERRA AND BREAK
APART AS IT DOES SO. THIS BAND OF MOISTURE SHOULD BRING MVFR
CEILINGS AND LIGHT RAIN SHOWERS TO THE KTRK TERMINAL AROUND 12Z BUT
SHOULD FALL APART BEFORE IT REACHES THE KTVL TERMINAL. LITTLE
MOISTURE IS EXPECTED TO GET OVER THE SIERRA CREST WITH LITTLE IMPACT
ON KRNO.
CS/JORDAN
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR NVZ002-003.
LAKE WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR NVZ004.
CA...WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR CAZ072.
&&
$$
HTTP://WEATHER.GOV/RENO
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
232 PM EST SUN DEC 2 2007
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE GREAT LAKES THIS
AFTERNOON AND THEN NEW ENGLAND MONDAY. A SECONDARY LOW WILL
DEVELOP NEAR LONG ISLAND EARLY MONDAY AND THEN COMBINE WITH THE
GREAT LAKES LOW MONDAY NIGHT NEAR CAPE COD. THIS DEEP STORM WILL
THEN SLOWLY EXIT TO THE NORTHEAST MONDAY NIGHT AND TUESDAY. AN
ALBERTA CLIPPER LOW PRESSURE SYSTEM IS THEN FORECAST TO WHIP AROUND
THIS LOW AND PASS OFF THE VIRGINIA COAST WEDNESDAY NIGHT OR
THURSDAY. BEHIND THIS CLIPPER A HIGH PRESSURE SYSTEM WILL BUILD
INTO THE EASTERN PART OF THE UNITED STATES FOR THE END OF THE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE PUBLIC PRODUCTS AND THE WSW HAVE BEEN REISSUED TO CANCEL THE
WINTER STORM ADVISORY FOR EASTERN MONMOUTH AND OCEAN COUNTIES. THE
TEMPERATURES HAVE BEEN SLOW TO RISE THIS AFTERNOON, SO THE
ADVISORY HAS BEEN EXTENDED IN TIME TO 5 PM ACROSS THE PHILADELPHIA
METRO AREA.
PREVIOUS DISCUSSION:
NOW ITS JUST A WAITING GAME FOR TEMPS TO RESPONSE. THE LACK OF
DEEP COLD WEATHER AND AS STRONG AS IT GETS INDIRECT INSOLATION
FROM THE DEC SUN HAS KEPT ROADWAYS MAINLY WET IN THE ADVY AREA. WE
DID GET REPORTS OF SOME ICING IN THE TREES AROUND THE LCL PHL
AREA, SO WE WILL CONT THE ADVY. GIVEN THE SLOWER RESPONSE OF
TEMPS, WE EXTENDED THE ADVY LATER IN THE AFTN IN THE RARITAN BASIN
AREA OF CENTRAL NJ. SNOW ACCUMS ARE GOING TO END CLOSE TO THE
LOWER END OF THE CUR FCST RANGE. WE REMOVED ACCUMS WHERE NO ADTNL
SNOW IS EXPECTED. SORRY WE HAVE NOT SEEN ANY RECENT ACARS DATA.
925MB/850MB TEMPS LOOK ABT 1C TOO COLD VS MDL INIT. MOST RECENT
ACARS FROM PHL ITS NOW ABV FREEZING FROM 750MB TO 850MB.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
MONDAY AND MONDAY NIGHT WILL BE WINDY AND A WIND ADVISORY HAS BEEN
ISSUED FOR GUSTS OF 50 MPH. WINDS AT 925 MB AND AT 850 MB ARE
FORECAST ABOVE 50 KT WITH AN ADIABATIC LAYER BELOW. THIS MEANS WE
WILL BE WELL MIXED AND SOME OF THE STRONGER WINDS FROM ALOFT WILL
MIX DOWN.
ANY PRECIPITATION WILL BE OVER BY DAYBREAK AS COLDER AND DRIER AIR
MOVES IN FROM THE WEST. TEMPERATURES WILL START OUT MILD IN THE
MORNING AND THEN FALL IN THE AFTERNOON. OTHERWISE IT WILL BE
PARTLY CLOUDY. SOME FLURRIES COULD DEVELOP NORTH IN THE AFTERNOON
AND CONTINUE INTO MONDAY NIGHT.
GUIDANCE TEMPS WERE ACCEPTED.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
CANADIAN HIGH PRESSURE WILL KEEP COLD WEATHER IN PLACE TUESDAY. A
CLIPPER SYSTEM COULD BRING SOME SNOW OR SNOW SHOWERS WEDNESDAY OR
WEDNESDAY NIGHT. ANOTHER COLD AREA OF HIGH PRESSURE IS FORECAST
FOR THURSDAY. HOWEVER, THIS TIME THE AIRMASS IF FORECAST TO MODIFY
AND TEMPERATURES TO INCREASE A BIT FRIDAY AND SATURDAY.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
A SOMEWHAT CHALLENGING FORECAST WITH RESPECT TO NOT ONLY
PRECIPITATION TYPE, BUT TO AREAL COVERAGE. LIGHT SNOW CAME IN
FASTER THAN EARLIER ANTICIPATED AND ONCE THE SNOW REACHED THE
SURFACE, THE CEILINGS QUICKLY LOWERED TO IFR AND LIFR, BUT THEN
BOUNCED BACK UP AGAIN WHEN THE SNOW EITHER ENDED OR LIGHTENED UP.
THE SNOW HAS BEEN CONFINED NORTH OF KPHL SO FAR WITH LITTLE GETTING
TO KILG, KMIV AND KACY. OCCASIONAL SNOW WILL CONTINUE FOR AWHILE
THIS MORNING AS THE AIR MASS IS PLENTY COLD. HOWEVER, WARMING WILL
TAKE PLACE ABOVE THE SURFACE ESPECIALLY DURING THE MORNING. THERE
MAY BE A LULL THOUGH FOR MOST LATER THIS MORNING. THE PRECIPITATION
WILL GO TO A MIX AND THEN TRANSITION TO PLAIN RAIN THROUGH THE
AFTERNOON FROM SOUTH TO NORTH. KPHL ALREADY OBSERVED SOME LIGHT
SLEET. KABE SHOULD BE THE LAST TO SEE THE FROZEN PRECIPITATION COME
TO AN END WITH SOME ICING QUITE POSSIBLE. KMIV AND KACY MAY NOT SEE
MUCH IN THE WAY OF FROZEN PRECIPITATION, HOWEVER WE STILL INDICATED
A POSSIBILITY OF A BRIEF PERIOD OF LIGHT SNOW AND SLEET EARLY. AS
DEW POINTS INCREASE, CEILINGS WILL LOWER TO IFR AND EVEN LIFR BY
EVENING. A SECONDARY SURGE OF MOISTURE WILL ARRIVE THIS AFTERNOON
AND REALLY GET GOING THIS EVENING, HOWEVER THIS SHOULD BE PRIMARILY
IN THE FORM OF RAIN FOR ALL THE TERMINALS. GENERALLY LIFR IS
EXPECTED TONIGHT, AND PROBABLY LASTING BEYOND 06Z MONDAY.
THERE MAY BE LOW-LEVEL WIND SHEAR AS NORTHEAST SURFACE WINDS TURN TO
THE SOUTHEAST DURING THE DAY. HOWEVER BETWEEN ABOUT 2000 AND 4000
FEET, THE WINDS ARE MORE FROM THE SOUTHWEST AND ARE FORECAST TO
INCREASE TO NEAR 35 KNOTS. WE MAY INCLUDE LOW-LEVEL WIND SHEAR IN
THE 12Z TAFS AFTER WE EXAMINE MORE DATA AND IF CONFIDENCE INCREASES.
BEYOND 06Z MONDAY...A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA
BRINGING AN END TO THE RAIN ALONG WITH DRYING. HOWEVER, WINDS WILL
BECOME A MAJOR FACTOR WITH GUSTS TO 45 KNOTS CERTAINLY POSSIBLE.
THIS APPEARS TO START AFTER 12Z MONDAY. THE NEXT SYSTEM WILL MOVE
THROUGH WEDNESDAY INTO THURSDAY AND COULD BRING SOME FROZEN
PRECIPITATION TO THE AREA.
&&
.MARINE...
A NORTHEASTERLY WIND HAS DOMINATED THE WATERS SO FAR AND THIS WILL
CONTINUE FOR AWHILE LONGER TODAY. AS A STORM MOVES INTO THE EASTERN
GREAT LAKES THIS AFTERNOON, A WARM FRONT WILL GRADUALLY SLIDE
NORTHWARD. THIS WILL TURN THE WINDS TO THE SOUTHEAST AND SOUTH AND
ALLOW FOR SOME INCREASE IN SPEEDS. AS THE STORM MOVES CLOSER, THE
WINDS ABOVE THE SURFACE WILL INCREASE QUITE A BIT, HOWEVER INITIALLY
A LOW-LEVEL INVERSION AS DEPICTED ON BUFKIT SOUNDINGS SHOULD KEEP
THE STRONGER WINDS FROM REACHING THE SURFACE. EVENTUALLY TONIGHT
THIS INVERSION IS ERODED AND GUSTS COULD REACH UP TO 30 KNOTS. AS A
RESULT, WE ISSUED A SMALL CRAFT ADVISORY STARTING AT 03Z ON THE
OCEAN AND LOWER BAY THEN AT 06Z ON THE UPPER BAY. THE ADVISORY WILL
GO UNTIL 11Z. A STRONG COLD FRONT WILL BLAST THROUGH OUR AREA EARLY
MONDAY AS A NEW STORM DEVELOPS AND INTENSIFIES IN SOUTHERN NEW
ENGLAND. A LOT OF WIND ENERGY IS FORECAST TO MOVE ACROSS OUR AREA ON
MONDAY, AND WITH STRONG CAA MOVING OVER THE MILDER WATER, THIS WILL
CREATE A VERY GOOD SETUP FOR MIXING OF THE STRONGER WINDS JUST ABOVE
THE SURFACE. THEREFORE, WE WENT WITH A GALE WARNING STARTING AT 11Z
ON MONDAY AND CONTINUED IT THROUGH 11Z ON TUESDAY. THIS MAY HAVE TO
BE EXTENDED AS GALE FORCE GUSTS MAY CONTINUE THROUGH A GOOD PART OF
TUESDAY. SOME STORM FORCE GUSTS WILL BE POSSIBLE, ESPECIALLY DURING
MONDAY AFTERNOON, HOWEVER CONFIDENCE IS NOT HIGH REGARDING THIS PLUS
WE ARE MORE THAN 24-HOURS OUT.
SEAS WILL ALSO INCREASE WITHIN THE SOUTHERLY FLOW SETUP TODAY AND
ESPECIALLY TONIGHT, THEN PEAK ON MONDAY AS THE WINDS TURN QUICKLY TO
THE WEST. WITH THE STRONG OFFSHORE FLOW ON MONDAY, THE HIGHEST SEAS
WILL BE FARTHER OFF THE COAST, HOWEVER ROUGH CONDITIONS WILL OCCUR.
THE STRONG OFFSHORE FLOW MAY ALSO CREATE LOWER THAN NORMAL TIDAL
LEVELS, HOWEVER WE NEED ABOUT 2 FEET TO REACH BLOWOUTS AND IT
APPEARS WE WILL NOT REACH THOSE LEVELS ATTM. WE WILL CONTINUE TO
MONITOR THIS THOUGH IN CASE A LOW WATER ADVISORY IS NEED FOR MONDAY.
WINDS WILL GRADUALLY SETTLE DOWN TUESDAY NIGHT AND WEDNESDAY. THE
NEXT SYSTEM WILL BE A CLIPPER TYPE ONE THAT MOVES THROUGH WEDNESDAY
INTO THURSDAY WITH THE POTENTIAL FOR SOME GUSTY WINDS FOR A TIME IN
ITS WAKE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ060>062.
WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR PAZ054-
055-060>062-067>071.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
PAZ067>069.
WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
PAZ070-071.
WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR PAZ054-055.
NJ...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ007-
008.
WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR NJZ001-
007>010-012>027.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NJZ009-
010.
WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
NJZ012-013-015-017>019.
WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR NJZ001.
DE...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR
DEZ001>004.
MD...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR MDZ008-
012-015-019-020.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ431-450>455.
GALE WARNING FROM 6 AM MONDAY TO 6 AM EST TUESDAY FOR ANZ430-
431-450>455.
SMALL CRAFT ADVISORY FROM 1 AM TO 6 AM EST MONDAY FOR ANZ430.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...GIGI/OHARA
SHORT TERM...STAUBER
LONG TERM...STAUBER
AVIATION...GORSE
MARINE...GORSE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
930 AM EST SUN DEC 2 2007
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE GREAT LAKES TODAY
AND THEN NEW ENGLAND MONDAY. A SECONDARY LOW WILL DEVELOP NEAR
LONG ISLAND EARLY MONDAY AND THEN COMBINE WITH THE GREAT LAKES
LOW MONDAY NIGHT NEAR CAPE COD. THIS DEEP STORM WILL THEN SLOWLY
EXIT TO THE NORTHEAST MONDAY NIGHT AND TUESDAY. AN ALBERTA
CLIPPER LOW PRESSURE SYSTEM IS THEN FORECASTTO WHIP AROUND THIS
LOW AND PASS OFF THE VIRGINIA COAST WEDNESDAY NIGHT OR THURSDAY.
BEHIND THIS CLIPPER A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
EASTERN PART OF THE UNITED STATES FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY/...
THIRD TWEAK, WE ENDED THE MENTION OF SNOW ACROSS THE SOUTHERN HALF
OF OUR CWA AS THE WARM AIR HAS MOVED IN ALOFT. NOW ITS JUST A
WAITING GAME FOR TEMPS TO RESPONSE. THE LACK OF DEEP COLD WEATHER
AND AS STRONG AS IT GETS INDIRECT INSOLATION FROM THE DEC SUN HAS
KEPT ROADWAYS MAINLY WET IN THE ADVY AREA. WE DID GET REPORTS OF
SOME ICING IN THE TREES AROUND THE LCL PHL AREA, SO WE WILL CONT THE
ADVY. GIVEN THE SLOWER RESPONSE OF TEMPS, WE EXTENDED THE ADVY LATER
IN THE AFTN IN THE RARITAN BASIN AREA OF CENTRAL NJ. SNOW ACCUMS ARE
GOING TO END CLOSE TO THE LOWER END OF THE CUR FCST RANGE. WE
REMOVED ACCUMS WHERE NO ADTNL SNOW IS EXPECTED. SORRY WE HAVE NOT
SEEN ANY RECENT ACARS DATA. 925MB/850MB TEMPS LOOK ABT 1C TOO COLD
VS MDL INIT. MOST RECENT ACARS FROM PHL ITS NOW ABV FREEZING FROM
750MB TO 850MB.
OVERNIGHT DISCUSSION:
THIS AFTN...THE STEADIER PCPN WILL SPREAD IN FROM THE WEST. WARM
AIR WILL ALSO CONTINUE TO ADVECT IN FROM THE SOUTH. THE WARM AIR
WILL ALLOW TEMPS TO RISE ABOVE FREEZING SLOWLY FROM SOUTH TO
NORTH. IN AREAS WHERE TEMPS ARE BELOW FREEZING, THE PCPN WILL
CHANGE TO FZRA AND SLEET. OTHERWISE, JUST RAIN WILL FALL WHERE
READINGS ARE ABOVE 32.
CONDITIONS WILL CONTINUE TO WARM TONIGHT EVENTUALLY CHANGING ALL
AREAS TO RAIN BY MONDAY MORNING.
SNOWFALL AMOUNTS LOOK LIKE 2 TO 4 INCHES NORTH WITH A PSBL
FREEZING RAIN OF 1/4 TO 1/2 INCH TOO. 5 INCHES COULD FALL LOCALLY.
JUST SOUTH OF THERE 1 TO 2 INCHES MAY FALL. IN THE PHILA METRO
AREA, THE ACCUMULATING SNOW SHOULD BE OVER THIS MORNING.
GFS MOS 3 HRLY TEMPS LOOK REASONABLE AND SEEM TO FCST THE HIGHS
TODAY BEST. TEMPS TONIGHT SHOULD CONTINUE RISING.
&&
.SHORT TERM /6 AM MONDAY THROUGH MONDAY NIGHT/...
MONDAY AND MONDAY NIGHT WILL BE WINDY AND A WIND ADVISORY HAS BEEN
ISSUED FOR GUSTS OF 50 MPH. WINDS AT 925 MB AND AT 850 MB ARE
FORECAST ABOVE 50 KT WITH AN ADIABATIC LAYER BELOW. THIS MEANS WE
WILL BE WELL MIXED AND SOME OF THE STRONGER WINDS FROM ALOFT WILL
MIX DOWN.
ANY PRECIPITATION WILL BE OVER BY DAYBREAK AS COLDER AND DRIER AIR
MOVES IN FROM THE WEST. TEMPERATURES WILL START OUT MILD IN THE
MORINNG AND THEN FALL IN THE AFTERNOON. OTHERWISE IT WILL BE
PARTLY CLOUDY. SOME FLURRIES COULD DEVELOP NORTH IN THE AFTERNOON
AND CONTINUE INTO MONDAY NIGHT.
GUIDANCE TEMPS WERE ACCEPTED.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
CANADIAN HIGH PRESSURE WILL KEEP COLD WEATHER IN PLACE TUESDAY. A
CLIPPER SYSTEM COULD BRING SOME SNOW OR SNOW SHOWERS WEDNESDAY OR
WEDNESDAY NIGHT. ANOTHER COLD AREA OF HIGH PRESSURE IS FORECAST
FOR THURSDAY. HOWEVER, THIS TIME THE AIRMASS IF FORECAST TO MODIFY
AND TEMPERATURES TO INCREASE A BIT FRIDAY AND SATURDAY.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
A SOMEWHAT CHALLENGING FORECAST WITH RESPECT TO NOT ONLY
PRECIPITATION TYPE, BUT TO AREAL COVERAGE. LIGHT SNOW CAME IN
FASTER THAN EARLIER ANTICIPATED AND ONCE THE SNOW REACHED THE
SURFACE, THE CEILINGS QUICKLY LOWERED TO IFR AND LIFR, BUT THEN
BOUNCED BACK UP AGAIN WHEN THE SNOW EITHER ENDED OR LIGHTENED UP.
THE SNOW HAS BEEN CONFINED NORTH OF KPHL SO FAR WITH LITTLE GETTING
TO KILG, KMIV AND KACY. OCCASIONAL SNOW WILL CONTINUE FOR AWHILE
THIS MORNING AS THE AIR MASS IS PLENTY COLD. HOWEVER, WARMING WILL
TAKE PLACE ABOVE THE SURFACE ESPECIALLY DURING THE MORNING. THERE
MAY BE A LULL THOUGH FOR MOST LATER THIS MORNING. THE PRECIPITATION
WILL GO TO A MIX AND THEN TRANSITION TO PLAIN RAIN THROUGH THE
AFTERNOON FROM SOUTH TO NORTH. KPHL ALREADY OBSERVED SOME LIGHT
SLEET. KABE SHOULD BE THE LAST TO SEE THE FROZEN PRECIPITATION COME
TO AN END WITH SOME ICING QUITE POSSIBLE. KMIV AND KACY MAY NOT SEE
MUCH IN THE WAY OF FROZEN PRECIPITATION, HOWEVER WE STILL INDICATED
A POSSIBILITY OF A BRIEF PERIOD OF LIGHT SNOW AND SLEET EARLY. AS
DEW POINTS INCREASE, CEILINGS WILL LOWER TO IFR AND EVEN LIFR BY
EVENING. A SECONDARY SURGE OF MOISTURE WILL ARRIVE THIS AFTERNOON
AND REALLY GET GOING THIS EVENING, HOWEVER THIS SHOULD BE PRIMARILY
IN THE FORM OF RAIN FOR ALL THE TERMINALS. GENERALLY LIFR IS
EXPECTED TONIGHT, AND PROBABLY LASTING BEYOND 06Z MONDAY.
THERE MAY BE LOW-LEVEL WIND SHEAR AS NORTHEAST SURFACE WINDS TURN TO
THE SOUTHEAST DURING THE DAY. HOWEVER BETWEEN ABOUT 2000 AND 4000
FEET, THE WINDS ARE MORE FROM THE SOUTHWEST AND ARE FORECAST TO
INCREASE TO NEAR 35 KNOTS. WE MAY INCLUDE LOW-LEVEL WIND SHEAR IN
THE 12Z TAFS AFTER WE EXAMINE MORE DATA AND IF CONFIDENCE INCREASES.
BEYOND 06Z MONDAY...A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA
BRINGING AN END TO THE RAIN ALONG WITH DRYING. HOWEVER, WINDS WILL
BECOME A MAJOR FACTOR WITH GUSTS TO 45 KNOTS CERTAINLY POSSIBLE.
THIS APPEARS TO START AFTER 12Z MONDAY. THE NEXT SYSTEM WILL MOVE
THROUGH WEDNESDAY INTO THURSDAY AND COULD BRING SOME FROZEN
PRECIPITATION TO THE AREA.
&&
.MARINE...
A NORTHEASTERLY WIND HAS DOMINATED THE WATERS SO FAR AND THIS WILL
CONTINUE FOR AWHILE LONGER TODAY. AS A STORM MOVES INTO THE EASTERN
GREAT LAKES THIS AFTERNOON, A WARM FRONT WILL GRADUALLY SLIDE
NORTHWARD. THIS WILL TURN THE WINDS TO THE SOUTHEAST AND SOUTH AND
ALLOW FOR SOME INCREASE IN SPEEDS. AS THE STORM MOVES CLOSER, THE
WINDS ABOVE THE SURFACE WILL INCREASE QUITE A BIT, HOWEVER INITIALLY
A LOW-LEVEL INVERSION AS DEPICTED ON BUFKIT SOUNDINGS SHOULD KEEP
THE STRONGER WINDS FROM REACHING THE SURFACE. EVENTUALLY TONIGHT
THIS INVERSION IS ERODED AND GUSTS COULD REACH UP TO 30 KNOTS. AS A
RESULT, WE ISSUED A SMALL CRAFT ADVISORY STARTING AT 03Z ON THE
OCEAN AND LOWER BAY THEN AT 06Z ON THE UPPER BAY. THE ADVISORY WILL
GO UNTIL 11Z. A STRONG COLD FRONT WILL BLAST THROUGH OUR AREA EARLY
MONDAY AS A NEW STORM DEVELOPS AND INTENSIFIES IN SOUTHERN NEW
ENGLAND. A LOT OF WIND ENERGY IS FORECAST TO MOVE ACROSS OUR AREA ON
MONDAY, AND WITH STRONG CAA MOVING OVER THE MILDER WATER, THIS WILL
CREATE A VERY GOOD SETUP FOR MIXING OF THE STRONGER WINDS JUST ABOVE
THE SURFACE. THEREFORE, WE WENT WITH A GALE WARNING STARTING AT 11Z
ON MONDAY AND CONTINUED IT THROUGH 11Z ON TUESDAY. THIS MAY HAVE TO
BE EXTENDED AS GALE FORCE GUSTS MAY CONTINUE THROUGH A GOOD PART OF
TUESDAY. SOME STORM FORCE GUSTS WILL BE POSSIBLE, ESPECIALLY DURING
MONDAY AFTERNOON, HOWEVER CONFIDENCE IS NOT HIGH REGARDING THIS PLUS
WE ARE MORE THAN 24-HOURS OUT.
SEAS WILL ALSO INCREASE WITHIN THE SOUTHERLY FLOW SETUP TODAY AND
ESPECIALLY TONIGHT, THEN PEAK ON MONDAY AS THE WINDS TURN QUICKLY TO
THE WEST. WITH THE STRONG OFFSHORE FLOW ON MONDAY, THE HIGHEST SEAS
WILL BE FARTHER OFF THE COAST, HOWEVER ROUGH CONDITIONS WILL OCCUR.
THE STRONG OFFSHORE FLOW MAY ALSO CREATE LOWER THAN NORMAL TIDAL
LEVELS, HOWEVER WE NEED ABOUT 2 FEET TO REACH BLOWOUTS AND IT
APPEARS WE WILL NOT REACH THOSE LEVELS ATTM. WE WILL CONTINUE TO
MONITOR THIS THOUGH IN CASE A LOW WATER ADVISORY IS NEED FOR MONDAY.
WINDS WILL GRADUALLY SETTLE DOWN TUESDAY NIGHT AND WEDNESDAY. THE
NEXT SYSTEM WILL BE A CLIPPER TYPE ONE THAT MOVES THROUGH WEDNESDAY
INTO THURSDAY WITH THE POTENTIAL FOR SOME GUSTY WINDS FOR A TIME IN
ITS WAKE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ060>062.
WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR PAZ054-
055-060>062-067>071.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
PAZ067>069.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
PAZ070-071.
WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR PAZ054-055.
NJ...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ007-
008.
WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR NJZ001-
007>010-012>027.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NJZ009-
010.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NJZ014-017>020.
WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR NJZ001.
WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
NJZ012-013-015.
DE...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR
DEZ001>004.
MD...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR MDZ008-
012-015-019-020.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ431-450>455.
GALE WARNING FROM 6 AM MONDAY TO 6 AM EST TUESDAY FOR ANZ430-
431-450>455.
SMALL CRAFT ADVISORY FROM 1 AM TO 6 AM EST MONDAY FOR ANZ430.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...GIGI/STAUBER
SHORT TERM...STAUBER
LONG TERM...STAUBER
AVIATION...GORSE
MARINE...GORSE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
820 AM EST SUN DEC 2 2007
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE GREAT LAKES TODAY
AND THEN NEW ENGLAND MONDAY. A SECONDARY LOW WILL DEVELOP NEAR
LONG ISLAND EARLY MONDAY AND THEN COMBINE WITH THE GREAT LAKES
LOW MONDAY NIGHT NEAR CAPE COD. THIS DEEP STORM WILL THEN SLOWLY
EXIT TO THE NORTHEAST MONDAY NIGHT AND TUESDAY. AN ALBERTA
CLIPPER LOW PRESSURE SYSTEM IS THEN FORECASTTO WHIP AROUND THIS
LOW AND PASS OFF THE VIRGINIA COAST WEDNESDAY NIGHT OR THURSDAY.
BEHIND THIS CLIPPER A HIGH PRESSURE SYSTEM WILL BUILD INTO THE
EASTERN PART OF THE UNITED STATES FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY/...
FIRST TWEAK OF THE FCST WILL BE TO UP THE SNOWFALL AMOUNTS UP N AS
THIS WAA SHOT HAS DONE WELL. REST OF FCST WILL PRETTY MUCH BE LEFT
AS IS. AS FAR AS ACARS SOUNDINGS GO, PHL IS STILL ALL SNOW, BWI IS
BIG TIME SLEET. THE WRF-NMM HAS TOTALLY MISSED THE ONGOING PCPN IN
SWRN PA/WV.
OVERNIGHT DISCUSSION:
CONTINUING TO FOLLOW CONTINUITY AND MODEL TRENDS, WAA CONTINUES THIS
AFTERNOON WITH ANOTHER AREA OF LIFT AND MOISTURE SPREADING IN FROM
THE WEST AND PROBABLY ASSOCIATED WITH THE DEVELOPING PCPN IN OHIO.
ALL THIS HAPPENS WHILE THERE IS WEAK RIDGING AT 500 MB. THIS RIDGE
WILL HAVE THE EFFECT OF KEEPING HIGH PRESSURE TO THE NORTH AND
THEREBY KEEPING COLD AIR TRAPPED AT THE SFC, MAINLY TO THE N/W OF
PHL. I WILL BE FOLLOWING THE FCST SOUNDINGS AND WITH SOME
CLIMATOLOGY ADDED. THIS MEANS THE COLD AIR WILL TEMPORARILY GET
STUCK OVER THE LEHIGH VALLEY, POCONOS AND NRN NJ. HOWEVER TEMPERATURS
EARLY THIS MORNING WERE QUITE COLD AND WERE AS LOW AS 10 DEGREES IN
FAR NW NJ TO THE LOW 20S JUST N OF PHL TO THE LOW 30S IN DELMARVA.
ON GOOD THING...WITH THE LIGHER PCPN THIS MORNING, SNOW, SLEET AND
FREEZING RAIN ARE IFFY TO THE S OF PHL AND THERE IS NO NEED TO
EXPAND THE WINTER WEATHER ADVISORY DUE TO LACK OF PCPN. IN THE
PHILA AND NEARBY AREAS, THE SNOW THAT FELL EARLY THIS MORNING HAS
MADE ROADS SLIPPERY AND IF ANY ADDITIONAL PCPN DEVELOPS IT COULD
BE IN THE FORM OF FREEZING RAIN, SLEET OR SNOW. THEREFORE THE
WINTER WX ADVISORY PREVIOUSLY ISSUED REMAINS IN EFFECT. AS THE
PCPN BECOMES STEADIER THIS AFTERNOON, TEMPS FROM PHL S/E SHOULD BE
ABOVE 32, BUT AT THE ONSET OF PCPN, SOME AREAS MIGHT STILL BE ARND
FREEZING.
THIS AFTN...THE STEADIER PCPN WILL SPREAD IN FROM THE WEST. WARM
AIR WILL ALSO CONTINUE TO ADVECT IN FROM THE SOUTH. THE WARM AIR
WILL ALLOW TEMPS TO RISE ABOVE FREEZING SLOWLY FROM SOUTH TO
NORTH. IN AREAS WHERE TEMPS ARE BELOW FREEZING, THE PCPN WILL
CHANGE TO FZRA AND SLEET. OTHERWISE, JUST RAIN WILL FALL WHERE
READINGS ARE ABOVE 32.
CONDITIONS WILL CONTINUE TO WARM TONIGHT EVENTUALLY CHANGING ALL
AREAS TO RAIN BY MONDAY MORNING.
SNOWFALL AMOUNTS LOOK LIKE 2 TO 4 INCHES NORTH WITH A PSBL
FREEZING RAIN OF 1/4 TO 1/2 INCH TOO. 5 INCHES COULD FALL LOCALLY.
JUST SOUTH OF THERE 1 TO 2 INCHES MAY FALL. IN THE PHILA METRO
AREA, THE ACCUMULATING SNOW SHOULD BE OVER THIS MORNING.
GFS MOS 3 HRLY TEMPS LOOK REASONABLE AND SEEM TO FCST THE HIGHS
TODAY BEST. TEMPS TONIGHT SHOULD CONTINUE RISING.
&&
.SHORT TERM /6 AM MONDAY THROUGH MONDAY NIGHT/...
MONDAY AND MONDAY NIGHT WILL BE WINDY AND A WIND ADVISORY HAS BEEN
ISSUED FOR GUSTS OF 50 MPH. WINDS AT 925 MB AND AT 850 MB ARE
FORECAST ABOVE 50 KT WITH AN ADIABATIC LAYER BELOW. THIS MEANS WE
WILL BE WELL MIXED AND SOME OF THE STRONGER WINDS FROM ALOFT WILL
MIX DOWN.
ANY PRECIPITATION WILL BE OVER BY DAYBREAK AS COLDER AND DRIER AIR
MOVES IN FROM THE WEST. TEMPERATURES WILL START OUT MILD IN THE
MORINNG AND THEN FALL IN THE AFTERNOON. OTHERWISE IT WILL BE
PARTLY CLOUDY. SOME FLURRIES COULD DEVELOP NORTH IN THE AFTERNOON
AND CONTINUE INTO MONDAY NIGHT.
GUIDANCE TEMPS WERE ACCEPTED.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
CANADIAN HIGH PRESSURE WILL KEEP COLD WEATHER IN PLACE TUESDAY. A
CLIPPER SYSTEM COULD BRING SOME SNOW OR SNOW SHOWERS WEDNESDAY OR
WEDNESDAY NIGHT. ANOTHER COLD AREA OF HIGH PRESSURE IS FORECAST
FOR THURSDAY. HOWEVER, THIS TIME THE AIRMASS IF FORECAST TO MODIFY
AND TEMPERATURES TO INCREASE A BIT FRIDAY AND SATURDAY.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
A SOMEWHAT CHALLENGING FORECAST WITH RESPECT TO NOT ONLY
PRECIPITATION TYPE, BUT TO AREAL COVERAGE. LIGHT SNOW CAME IN
FASTER THAN EARLIER ANTICIPATED AND ONCE THE SNOW REACHED THE
SURFACE, THE CEILINGS QUICKLY LOWERED TO IFR AND LIFR, BUT THEN
BOUNCED BACK UP AGAIN WHEN THE SNOW EITHER ENDED OR LIGHTENED UP.
THE SNOW HAS BEEN CONFINED NORTH OF KPHL SO FAR WITH LITTLE GETTING
TO KILG, KMIV AND KACY. OCCASIONAL SNOW WILL CONTINUE FOR AWHILE
THIS MORNING AS THE AIR MASS IS PLENTY COLD. HOWEVER, WARMING WILL
TAKE PLACE ABOVE THE SURFACE ESPECIALLY DURING THE MORNING. THERE
MAY BE A LULL THOUGH FOR MOST LATER THIS MORNING. THE PRECIPITATION
WILL GO TO A MIX AND THEN TRANSITION TO PLAIN RAIN THROUGH THE
AFTERNOON FROM SOUTH TO NORTH. KPHL ALREADY OBSERVED SOME LIGHT
SLEET. KABE SHOULD BE THE LAST TO SEE THE FROZEN PRECIPITATION COME
TO AN END WITH SOME ICING QUITE POSSIBLE. KMIV AND KACY MAY NOT SEE
MUCH IN THE WAY OF FROZEN PRECIPITATION, HOWEVER WE STILL INDICATED
A POSSIBILITY OF A BRIEF PERIOD OF LIGHT SNOW AND SLEET EARLY. AS
DEW POINTS INCREASE, CEILINGS WILL LOWER TO IFR AND EVEN LIFR BY
EVENING. A SECONDARY SURGE OF MOISTURE WILL ARRIVE THIS AFTERNOON
AND REALLY GET GOING THIS EVENING, HOWEVER THIS SHOULD BE PRIMARILY
IN THE FORM OF RAIN FOR ALL THE TERMINALS. GENERALLY LIFR IS
EXPECTED TONIGHT, AND PROBABLY LASTING BEYOND 06Z MONDAY.
THERE MAY BE LOW-LEVEL WIND SHEAR AS NORTHEAST SURFACE WINDS TURN TO
THE SOUTHEAST DURING THE DAY. HOWEVER BETWEEN ABOUT 2000 AND 4000
FEET, THE WINDS ARE MORE FROM THE SOUTHWEST AND ARE FORECAST TO
INCREASE TO NEAR 35 KNOTS. WE MAY INCLUDE LOW-LEVEL WIND SHEAR IN
THE 12Z TAFS AFTER WE EXAMINE MORE DATA AND IF CONFIDENCE INCREASES.
BEYOND 06Z MONDAY...A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA
BRINGING AN END TO THE RAIN ALONG WITH DRYING. HOWEVER, WINDS WILL
BECOME A MAJOR FACTOR WITH GUSTS TO 45 KNOTS CERTAINLY POSSIBLE.
THIS APPEARS TO START AFTER 12Z MONDAY. THE NEXT SYSTEM WILL MOVE
THROUGH WEDNESDAY INTO THURSDAY AND COULD BRING SOME FROZEN
PRECIPITATION TO THE AREA.
&&
.MARINE...
A NORTHEASTERLY WIND HAS DOMINATED THE WATERS SO FAR AND THIS WILL
CONTINUE FOR AWHILE LONGER TODAY. AS A STORM MOVES INTO THE EASTERN
GREAT LAKES THIS AFTERNOON, A WARM FRONT WILL GRADUALLY SLIDE
NORTHWARD. THIS WILL TURN THE WINDS TO THE SOUTHEAST AND SOUTH AND
ALLOW FOR SOME INCREASE IN SPEEDS. AS THE STORM MOVES CLOSER, THE
WINDS ABOVE THE SURFACE WILL INCREASE QUITE A BIT, HOWEVER INITIALLY
A LOW-LEVEL INVERSION AS DEPICTED ON BUFKIT SOUNDINGS SHOULD KEEP
THE STRONGER WINDS FROM REACHING THE SURFACE. EVENTUALLY TONIGHT
THIS INVERSION IS ERODED AND GUSTS COULD REACH UP TO 30 KNOTS. AS A
RESULT, WE ISSUED A SMALL CRAFT ADVISORY STARTING AT 03Z ON THE
OCEAN AND LOWER BAY THEN AT 06Z ON THE UPPER BAY. THE ADVISORY WILL
GO UNTIL 11Z. A STRONG COLD FRONT WILL BLAST THROUGH OUR AREA EARLY
MONDAY AS A NEW STORM DEVELOPS AND INTENSIFIES IN SOUTHERN NEW
ENGLAND. A LOT OF WIND ENERGY IS FORECAST TO MOVE ACROSS OUR AREA ON
MONDAY, AND WITH STRONG CAA MOVING OVER THE MILDER WATER, THIS WILL
CREATE A VERY GOOD SETUP FOR MIXING OF THE STRONGER WINDS JUST ABOVE
THE SURFACE. THEREFORE, WE WENT WITH A GALE WARNING STARTING AT 11Z
ON MONDAY AND CONTINUED IT THROUGH 11Z ON TUESDAY. THIS MAY HAVE TO
BE EXTENDED AS GALE FORCE GUSTS MAY CONTINUE THROUGH A GOOD PART OF
TUESDAY. SOME STORM FORCE GUSTS WILL BE POSSIBLE, ESPECIALLY DURING
MONDAY AFTERNOON, HOWEVER CONFIDENCE IS NOT HIGH REGARDING THIS PLUS
WE ARE MORE THAN 24-HOURS OUT.
SEAS WILL ALSO INCREASE WITHIN THE SOUTHERLY FLOW SETUP TODAY AND
ESPECIALLY TONIGHT, THEN PEAK ON MONDAY AS THE WINDS TURN QUICKLY TO
THE WEST. WITH THE STRONG OFFSHORE FLOW ON MONDAY, THE HIGHEST SEAS
WILL BE FARTHER OFF THE COAST, HOWEVER ROUGH CONDITIONS WILL OCCUR.
THE STRONG OFFSHORE FLOW MAY ALSO CREATE LOWER THAN NORMAL TIDAL
LEVELS, HOWEVER WE NEED ABOUT 2 FEET TO REACH BLOWOUTS AND IT
APPEARS WE WILL NOT REACH THOSE LEVELS ATTM. WE WILL CONTINUE TO
MONITOR THIS THOUGH IN CASE A LOW WATER ADVISORY IS NEED FOR MONDAY.
WINDS WILL GRADUALLY SETTLE DOWN TUESDAY NIGHT AND WEDNESDAY. THE
NEXT SYSTEM WILL BE A CLIPPER TYPE ONE THAT MOVES THROUGH WEDNESDAY
INTO THURSDAY WITH THE POTENTIAL FOR SOME GUSTY WINDS FOR A TIME IN
ITS WAKE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
PAZ060>062.
WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR PAZ054-
055-060>062-067>071.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
PAZ067>069.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
PAZ070-071.
WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR PAZ054-055.
NJ...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ007-
008.
WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR NJZ001-
007>010-012>027.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NJZ009-
010.
WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
NJZ012>015-017>020.
WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR NJZ001.
DE...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR
DEZ001>004.
MD...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR MDZ008-
012-015-019-020.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ431-450>455.
GALE WARNING FROM 6 AM MONDAY TO 6 AM EST TUESDAY FOR ANZ430-
431-450>455.
SMALL CRAFT ADVISORY FROM 1 AM TO 6 AM EST MONDAY FOR ANZ430.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...STAUBER
SHORT TERM...STAUBER
LONG TERM...STAUBER
AVIATION...GORSE
MARINE...GORSE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
336 PM EST SUN DEC 2 2007
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)
LARGE PRECIP AREA AHEAD OF ADVANCING COLD FRONT HAS BEEN STRATIFYING
THE PAST SERVERAL HOURS WITH CG LIGHTNING ON THE DECLINE OVER THE
PAST 2 HOURS. THANKS TO THE PERSISTENT CLOUD COVER...CHANCES OF
INTENSIFICATION ARE MINIMAL SO RAIN WITH A FEW EMBEDDED
THUNDERSTORMS IS BEST BET. ONE OF THE TRICKIEST ISSUES IS HOW MUCH
CLEARING WILL OCCUR AFTER THE FROPA AS NORTHWEST WINDS USHER IN MUCH
DRIER AIR. WHILE MODELS ALL DEEP MOISTURE DRYING OUT...BOUNDARY
LAYER REMAINS MOIST THROUGH THE NIGHT...SO AM DOUBTFUL OF MUCH
CLEARING UNTIL MIXING BEGINS AFTER SUNRISE TOMORROW. THIS RESULTS
IN A BATTLE OVER HOW MUCH COLD AIR ADVECTION WILL PLAY IN MIN
TEMPERATURES AS RADIATIONAL COOLING SHOULD BE NIL.
BOTTOM LINE...A WET EVENING WITH A RAPID COOL DOWN IN THE FIRST 2-3
HOURS AFTER FROPA. THOUGH CLOUDS WILL REMAIN...DO NOT EXPECT
ANYTHING BUT LIQUID PRECIP AS COLDER AND MUCH DRIER MOVES IN. NOT
MUCH WARMING TOMORROW WITH HIGHS ONLY IN THE UPPER 30S TO LOWER 40S
BEFORE DROPPING INTO THE 20S MONDAY NIGHT WITH CLEARING SKIES.
.LONG TERM (TUESDAY THROUGH SATURDAY NIGHT)...
TUESDAY THROUGH WEDNESDAY NIGHT...
LONG TERM PERIOD STARTS OUT WITH HIGH PRESSURE CENTERED OVER TX ON
TUES WHICH WILL QUICKLY MOVE SWRD AS THE MIDWEST SITS UNDER A FAST
NW MID LEVEL FLOW. PARTLY CLOUDY TO MOSTLY CLEAR SKIES WILL ALLOW
MIN TEMPS TUES MORNING TO DROP INTO THE MID TO UPPER 20S. AFTER A
CHILLY START TEMPS WILL REBOUND INTO THE 40S WITH CLOUDS ON THE
INCREASE AS A SYSTEM APPROACHES FROM THE NW FOR TUESDAY NIGHT.
MODELS HAVE SPED UP ARRIVAL OF NORTHERN STREAM SHRT/WV AND
ASSOCIATED SFC LOW OVER THE PAST FEW DAYS. 12Z GEM/GFS/ECMWF ALL IN
PRETTY GOOD AGREEMENT WITH TIMING OF THIS SYSTEM WHICH LOOKS TO
IMPACT THE AREA TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. WILL THROW
OUT THE 12Z ETA WHICH WRAPS UP THE SFC LOW TOO MUCH GIVEN FAST NW
FLOW. NOT A WHOLE LOT OF MOISTURE WITH THIS SYSTEM SO EXPECTING
LIGHT PRECIP. AS FAR AS PRECIP TYPE...MODEL SOUNDS AND TIME HEIGHT
CROSS SECTION SUGGEST LIGHT SNOW OR RAIN TUES NIGHT/WED MORNING IN
THE N AND RAIN IN THE S FA. THEN WILL CHANGE ALL TO RAIN WED
AFTERNOON SAVE FOR THE EXTREME NRN FA WHICH COULD SEE RAIN OR SNOW.
AS TEMPS BEGIN TO FALL WED NIGHT...WILL CHANGE ENTIRE FA TO SNOW AS
A DECENT PUNCH OF COLD AIR COMES IN BEHIND THIS CLIPPER.
THURSDAY THROUGH SATURDAY NIGHT...
BEYOND THURS...FORECAST CONFIDENCE IS FAIRLY LOW AS MODELS ARE
HAVING A HARD TIME RESOLVING MID LEVEL ENERGY WHICH TOPPLES WEST
COAST RIDGING EARLY IN THE WEEK CREATING SEVERAL WAVES OF ENERGY
CROSSING THE ERN CONUS BY LATE NEXT WEEK. FIRST SYSTEM LOOKS TO
APPROACH IN THE FRI/SAT TIME RANGE ALTHOUGH GEM/ECMWF/GFS ALL OFFER
VERY DIFFERENT TIMING TO THIS SYSTEM. WILL NOT CHANGE POPS AT THIS
POINT SINCE THEY OFFER A MIDDLE OF THE ROAD SOLN WHICH SEEMS BEST
FOR NOW. DIFFERENCE IN TIMING SEEMS TO COME FROM THE EJECTION OF A
TROUGH OFF OF THE ROCKIES AND ANOTHER OVER CANADA. THEN THE
QUESTION IS WILL THEY PHASE OR NOT AS THEY MOVE EWRD.
AS FOR TEMPS...THESE COULD CHANGE QUITE A BIT AS MODELS RESOLVE
THESE LATE WEEK ENERGY WAVES. WENT MIDDLE OF THE ROAD BETWEEN
GUIDANCE AND RAW MODEL DATA FOR NOW. TEMPS SHOULD WARM NEAR THE END
OF THE PERIOD AHEAD OF NEXT MAJOR SYSTEM WHICH LOOKS TO OCCUR EARLY
NEXT WEEK.
&&
AVIATION (18Z TAFS)...
LARGE AREA OF RAINFALL WELL AHEAD OF APPROACHING COLD FRONT LINGERS
AT LEX AS OF 17Z BUT WILL CONTINUE TO WEAKEN AS IT EXITS TO THE
EAST. SURFACE WINDS ON THE BACK SIDE OF THE SHOWERS FINALLY STARTED
TO GUST INTO 20S AS SLIGHT MIXING BEGINS. EVEN WITH SFC WINDS
GUSTING INTO 20S...LATEST ACARS SOUNDINGS FROM SDF SHOW 50KT WINDS
AT 2500 AGL...SO LLWS WILL CONTINUE TO BE A PROBLEM IN ADVANCE OF
FROPA. LINE OF THUNDERSTORMS FORMING ALONG COLD FRONT WILL BE OF
CONCERN LATER THIS AFTERNOON INTO EARLY EVENING AS FRONT APPROACHES.
BOTTOM LINE...IFR AND MVFR CONDITIONS TO PREVAIL WITH STRONG WINDS
UNTIL FRONT IS WELL PAST.
&&
LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
SHORT TERM...JBS
LONG TERM....AL
AVIATION.....JBS
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1211 PM EST SUN DEC 2 2007
.AVIATION...
LARGE AREA OF RAINFALL WELL AHEAD OF APPROACHING COLD FRONT
LINGERS AT LEX AS OF 17Z BUT WILL CONTINUE TO WEAKEN AS IT EXITS
TO THE EAST. SURFACE WINDS ON THE BACK SIDE OF THE SHOWERS
FINALLY STARTED TO GUST INTO 20S AS SLIGHT MIXING BEGINS. EVEN
WITH SFC WINDS GUSTING INTO 20S...LATEST ACARS SOUNDINGS FROM SDF
SHOW 50KT WINDS AT 2500 AGL...SO LLWS WILL CONTINUE TO BE A
PROBLEM IN ADVANCE OF FROPA. LINE OF THUNDERSTORMS FORMING ALONG
COLD FRONT WILL BE OF CONCERN LATER THIS AFTERNOON INTO EARLY
EVENING AS FRONT APPROACHES. BOTTOM LINE...IFR AND MVFR
CONDITIONS TO PREVAIL WITH STRONG WINDS UNTIL FRONT IS WELL PAST.
JBS
&&
.PREV DISCUSSION... /ISSUED 600 AM EST SUN DEC 2 2007/
SHORT TERM (TODAY AND TONIGHT)...
SCATTERED PRECIPITATION ASSOCIATED WITH SOME WAVE ENERGY AND A WARM
FRONT TO CONTINUE ACROSS THE NORTHERN ZONES FOR THE NEXT SEVERAL
HOURS WITH ONLY A COUPLE HUNDREDTHS LIKELY FROM ANYTHING THAT
REACHES THE GROUND IN A STILL RELATIVELY DRY AIR MASS. WARM FRONT
MOVES OFF TO THE NORTH BY MID MORNING WITH CONTINUED WARMING OF
TEMPS INTO THE LOWER TO MID 60S FOR MOST OF THE AREA WITH MOISTURE
ADVECTION ONGOING THROUGHOUT THE DAY. STRONGER WINDS ALREADY
DEVELOPING ACROSS THE WESTERN ZONES WILL FILTER EAST THROUGHOUT THE
MORNING AND HAVE CONTINUED 15-25 WITH HIGHER GUSTS AS INHERITED.
ANOTHER BATCH OF WAVE ENERGY AHEAD OF A STRONG COLD FRONT TO REACH
THE SOUTHWESTERN ZONES JUST BEFORE NOON WITH RAIN SHOWERS SPREADING
TO THE EAST/NORTHEAST WELL AHEAD OF THE FRONT EARLY THIS AFTERNOON.
A BRIEF BREAK FROM PRECIPITATION IS LIKELY TO OCCUR THIS AFTERNOON
BEFORE THE FRONT FINALLY GETS TO SOUTHERN INDIANA AND CENTRAL
KENTUCKY EARLY THIS EVENING. ONCE THE FRONT DOES REACH THE AREA IT
WILL MOVE THROUGH RATHER QUICKLY...WITH PASSAGE UP TO THE OHIO RIVER
AROUND 7PM AND THROUGH THE FAR EASTERN ZONES BY 10-11PM OR SO. IN
ADDITION TO MORE PRECIPITATION...THUNDERSTORMS STILL A POSSIBILITY
AS VERY STRONG JET AND DECENT MID LEVEL LAPSE RATES MOVE INTO THE
AREA. NOT EXPECTING ANYTHING SEVERE AT THIS TIME...BUT WITH THE
AMOUNT OF WIND POTENTIAL THAT IS ASSOCIATED WITH THE FRONT THE AREA
COULD SEE SOME ISOLATED WINDS OVER 50+ MPH WITH ANY STORMS THAT DO
DEVELOP.
STRONG COLD AIR ADVECTION BEHIND THE FRONT TO HELP DRIVE CONTINUED
WINDY CONDITIONS THROUGH MUCH OF THE TONIGHT PERIOD AND HAVE
INCREASED GUSTS OVERNIGHT. TEMPERATURES WILL FALL RATHER RAPIDLY AS
WELL WITH EARLY EVENING TEMPS IN THE UPPER 50S AND LOWER 60S DROPPING
INTO THE UPPER 20S TO AROUND 30 BY SUNRISE MONDAY.
PRECIPITATION ASSOCIATED WITH THE FRONT TO SHUT OFF WITHIN 3HRS OR SO
OF FRONTAL PASSAGE WITH RAPID STABILIZATION AND DRYING OF THE AIR
MASS BEHIND THE FRONT. SOME LIGHT SHOWERS COULD REMAIN
ESPECIALLY OUT EAST THROUGH MUCH OF THE TONIGHT PERIOD BUT
PRECIPITATION SHOULD COME TO AN END BY AROUND 4AM AT THE LATEST.
SHORTLY AFTER THAT BUFKIT PROFILES BECOME FAVORABLE FOR SOME VERY
LIGHT FROZEN PRECIPITATION...SO IF ANYTHING DOES INDEED LINGER
LONGER THAN CURRENTLY ANTICIPATED THERE COULD BE A FEW FLURRIES OR
SOME VERY LIGHT FREEZING DRIZZLE IN THE EXTREME EASTERN COUNTIES
BEFORE DAWN.
LONG TERM (MONDAY THROUGH SATURDAY)...
MONDAY-TUESDAY...
FRONT WILL BE THROUGH THE AREA AT THE BEGINNING OF THIS TIME PERIOD.
MONDAY SHOULD BE A COLD AND BLUSTERY DAY WITH GUSTS AT TIMES TO
AROUND 25 MPH. OVERALL COLUMN OF AIR WILL BE VERY DRY...EXCEPT FOR
SOME LOW-LEVEL STRATO-CU THAT MAY FILTER INTO THE AREA FROM THE NW.
THESE CLOUDS AND GOOD CAA WILL HELP KEEP HIGH TEMPS LOWER THAN
GUIDANCE MOST LIKELY. HIGHS SHOULD RANGE FROM THE UPPER 30S NORTH TO
LOW/MID 40S SOUTH. MONDAY NIGHT SHOULD BE CLEAR WITH COLD OVERNIGHT
LOWS IN THE LOW TO UPPER 20S.
FAST 500MB FLOW WILL BRING THE NEXT SHORTWAVE/LOW PRESSURE SYSTEM
SCREAMING TOWARD THE CWA LATE TUESDAY. CLOUDS WILL BE ON THE
INCREASE WITH HIGH TEMPS REBOUNDING ABOUT 5 DEGREES. INTRODUCED
TUESDAY NIGHT POPS (LOW CHC N TO SLT CHC S) AS THIS SYSTEM QUICKLY
APPROACHES FROM THE NW. QPF AMOUNTS ARE LOW...BUT GOOD GFS/EURO AND
ENSEMBLE AGREEMENT SUPPORT LIGHT PRECIP MAINLY OVER NRN KY AND
NORTHWARD. LOW TEMPS WILL DROP TO AROUND 30 N TO THE MID 30S S...SO
HAVE A RAIN/SNOW MIX OVER THE SOUTH WITH SNOW OVER THE NORTH.
WEDNESDAY-THURSDAY...
THINK THE MAIN CHANCE OF PRECIP WILL COME WHEN A POTENT CLIPPER
SYSTEM ON THE HEELS OF THE TUESDAY NIGHT SYSTEM APPROACHES THE
REGION WEDNESDAY AFTERNOON-NIGHT. MODELS HAVE BEEN INCREASINGLY
FASTER OVER THE PAST 4 MODEL RUNS...SO BUMPED UP POPS ON WEDNESDAY.
DEPENDING ON TEMPS...THINK PRECIP WOULD BE A LIGHT RAIN/SNOW MIX IN
THE MORNING CHANGING OVER TO LIGHT RAIN IN THE AFTERNOON.
THE MAIN CLIPPER SWEEPS ACROSS THE AREA WED AFTN-NIGHT...AND WITH
PROGGED 850MB TEMPS FROM THE GFS/EURO DROPPING TO -10 CELSIUS...THIS
WILL PROVIDE A GOOD CHANCE OF SNOW ESPECIALLY IF THIS CLIPPER KEEPS
THE SAME TRACK AND INTENSITY. WILL NOT EVEN ATTEMPT SNOW AMOUNTS YET
SINCE A LOT DEPENDS ON THE TRACK OF THIS SYSTEM AND GIVEN THAT
GROUND TEMPS OVER THE PAST WEEK FROM OUR COOP OBSERVERS HAVE RANGED
FROM THE LOW 40S N TO THE LOW 50S S...WHICH IS STILL ON THE WARM
SIDE DESPITE THE COLD AIR TEMPS OF LATE. HOWEVER AS I STATED
YESTERDAY...IT LOOKS LIKE A GOOD SHOT AT SOME ACCUMULATING SNOWS
ESPECIALLY OVER OUR NERN CWA INCLUDING THE NRN BLUEGRASS.
TEMPS ARE TRICKY FOR THURSDAY. I LIKED THE PREVIOUS FORECASTERS
BELOW GUIDANCE HIGHS FOR THURSDAY. TEMPS SHOULD NOT GET OUT OF THE
30S (EXCEPT FOR MAYBE LOCATIONS BY THE TENNESSEE
BORDER)...ESPECIALLY IF ANY SNOW ACCUMULATES.
FRIDAY-SATURDAY...
MADE NO CHANGES TO THIS PERIOD. QUICK AND ACTIVE ZONAL FLOW MOVES
THE SFC HIGH OFF TO THE EAST SWIFTLY...WITH A FAST LEE ROCKIES
SHORTWAVE DEVELOPING EARLY FRIDAY ACROSS THE MID MS VLY REGION. THIS
APPEARS TO BRING A QUICK CHANCE OF PRECIP FRIDAY SOMETIME (WHEN THE
MODELS YESTERDAY SHOWED THIS OCCURRING ON SATURDAY)...WITH ANOTHER
SFC HIGH PRESSURE SETTLING IN BEHIND IT ON SATURDAY.
AVIATION (12Z TAFS)...
SURFACE WINDS AND WIND SHEAR CONTINUE THROUGH MUCH OF THE TAF PERIOD
WITH 40-60KT LOW LEVEL JET JUST OFF THE SURFACE FOR THE FIRST 12
HOURS OF THE TAF PERIOD. SURFACE FLOW IN THE SAME GENERAL DIRECTION
OF THE LOW LEVEL JET...SO SPEED SHEAR THE MAIN CONCERN WITH THESE
STRONG WINDS JUST OFF THE SURFACE. WIND SHIFT AT ALL LEVELS TO THE
NORTHWEST EXPECTED BEHIND A COLD FRONT AFTER 00Z...DIMINISHING THE
LLWS THREAT EVEN THOUGH GUSTY SURFACE WINDS WILL CONTINUING THROUGH
06Z.
RAIN SHOWERS WITH MVFR CEILINGS WILL BE LIKELY AT TIMES THROUGH 06Z
MONDAY AS WELL. ISOLATED TO SCATTERED THUNDERSTORMS WITH ISOLATED
IFR CONDITIONS WILL BE POSSIBLE FROM AROUND 18Z SUNDAY - 03Z MONDAY.
LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
$$
SHORT TERM...MACZKO
LONG TERM....AL
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM...AB
LONG TERM....AB
AVIATION...JBS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
350 PM EST SUN DEC 2 2007
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE FROM THE UPPER MIDWEST
INTO NEW ENGLAND TODAY...WITH A TRAILING COLD FRONT PUSHING OFF
THE EAST COAST BY MONDAY AFTERNOON. A FRONTAL BOUNDARY WILL
CONTINUE TO BE DRAPED ACROSS THE REGION AS A SERIES OF SHORTWAVES
MOVE WEST TO EAST ALONG IT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
EARLY AFTERNOON ANALYSIS SHOWING SFC LOW PRESSURE OVER NORTHERN
MICHIGAN...WITH STRONG COLD FRONT SNAKING BACK INTO MIDDLE MO VLY
AND SOUTHERN PLAINS. CLOSER TO HOME...HIGH PRESSURE WAS OFF THE NE
CONUS COASTLINE.
HOLES IN RADAR ACTIVITY STARTING TO FILL IN ATTM...AS WAA INDUCED
SHRAS PROPAGATE INTO THE REGION. GOING CATEGORICAL POPS N/LKLY
POPS SOUTH STILL LOOKING GOOD....WITH ACTIVITY BECOMING MORE AND
MORE SPARSE AFTER MIDNIGHT WITH MOISTURE TRANSPORT VECTORS SHOWING
DRY AIR INFILTRATING WESTERN CWA AFTER 06-09Z. MAJORITY OF
APPRECIABLE RAINFALL...IF IT CAN BE CALLED THAT...WILL BE OVER THE
NORTHERN HALF OF THE CWA...WITH LIGHTER MORE SPORADIC RNFALL
EXPECTED SOUTH. RAIN ACROSS EVEN THE NORTH WILL LKLY NOT RUN MUCH
MORE THAN A QUARTER TO HALF AN INCH OVER THE AREA TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
DRY AIR QUICKLY MOVES INTO THE REGION AT LOW/MID LVLS BEHIND
FRONTAL PASSAGE TWRDS 12Z MON. WILL KEEP -RA MENTION OVER COASTAL
NE NC/IVOF OXB THROUGH MID AM.
NEXT ISSUE AFTER THE RAIN TAPERS OFF WILL BE THE WIND. HAVE
HOISTED A WIND ADVY FOR THE NORTHERN NECK OF VA AND EASTERN SHORE
COUNTIES. GFS AND BUFR DATA ADVERTISING GOOD MOMENTUM TRANSFER/STRONG
SUBSIDENCE BEYOND FRONT...WITH GUSTS OF 50-60 KT AT 92MB. GIVEN
SUBSIDENCE...FEEL THAT WE SHOULD HAVE NO PROBLEM MIXING AT LEAST
SOME OF THOSE POTENTIALLY DAMAGING GUSTS DOWN TO THE SFC AFTER
SUNRISE...ESP WITH MIDLVL BNDRY PUSHING THRU BY MID-MORNING...WITH
WNDS PERSISTING INTO MONDAY NIGHT BEFORE WNDS FINALLY DECOUPLE BY
TUESDAY WHEN GRADIENT FINALLY RELAXES. WL GO AHEAD AND OUTLOOK THE
COUNTIES IN THE HWO FOR DAMAGING WNDS POTENTIAL.
COOL WEATHER ON TUESDAY WITH NW FLOW ALOFT AND GENLY BENIGN CONDITIONS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ACTIVE PATTERN CONTINUES...AS EYES THEN TURN TO POTENTIAL (LIGHT) PCPN
FROM CLIPPER SYSTEM WED/THU. GFS/ECMWF ADVERTISING AFOREMENTIONED
COLD FRONT LIFTING BACK NORTHWARD OVER THE REGION AS A SHORTWV
RIDES W/E ALONG IT FROM THE OHIO VLY. GFS MODEL SNGS SHOW MID LVLS
SATURATING (H85-50) ABV 90% OVER THE NRN HALF OF THE CWA AS EARLY
AS LGT TUESDAY NIGHT OVER WESTERN CWA...TOWARDS DAWN WED FURTHER
EAST. CAVEAT TO THAT IS THAT GIVEN THE LATEST FORECAST SOUNDINGS
ALONG A LINE FROM AVC-RZZ-NTU AND SOUTHWARD...LOWRD POPS TO SILENT OVER
SOUTHERN THIRD OF CWA.
TRIED NOT TO GET TOO SPECIFIC IN GRIDS WITH TIMING STILL IN DOUBT
GIVEN VAST DIFFERENCES BETWEEN NAM AND GFS/ECMWF ATTM.
(STRONGER/FARTHER N NAM SOLN GENLY DISREGARDED FOR THIS PACKAGE).
AGAINST BETTER JUDGMENT...DECIDED TO TAKE FIRST SHOT AT PTYPES...WITH
THE IDEA THAT IT CAN BE REFINED AS WE GO. IN ANY CASE...SEEMS THAT
TEMPS SHUD BECOME WARM ENOUGH TO BECOME ALL RAIN FOR MOST IF NOT
ENTIRE AKQ CWFA BY MID-MORNING WED. STILL TOO FAR OUT TO GET TO
SPECIFIC ON POSSIBLE SNOW ACCUMS...BUT BEST CHC FOR ANY
APPRECIABLE (LIGHT) SNOWFALL WILL BE OVER NORTHERN THIRD OF THE
CWA. STAY TUNED.
HIGH PRESSURE BUILDS OVER THE REGION THURSDAY WITH CONTINUED
COOLER THAN NORMAL VALUES NOTED AREAWIDE. ANOTHER FRONTAL SYSTEM
LOOKS TO CROSS THE AREA BY THE WEEKEND. FOLLOWING THE LEAD OF THE
ECMWF...HV DECIDED TO KEEP FROPA DRY GIVEN INHERITED DRY FORECAST
RATHER THAN TAKE A FLIER ON MORE MOISTURE LADEN (LATEST 12Z 2-DEC)
GFS SOLN.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
LOW PRESSURE SYSTEM WILL CROSS THE GREAT LAKES OVERNIGHT AND
EARLY MON. COLD FRONT TRAILING S/SW FROM THE LOW WILL APPROACHES THE
REGION TODAY...THEN CROSSES THE AREA LATE TONIGHT AND EARLY ON MON.
MID/UPPER LEVEL CLOUD DECKS DEVELOPED OVER THE SRN SITES THIS
MORNING. ANTICIPATE VFR/HI-END MVFR CIGS DURING THE EVENING AND
OVERNIGHT HOURS...COINCIDING WITH THE AXIS OF MAXIMUM LLVL
MOISTURE AND AREAS OF SHOWERS ALONG/AHEAD OF THE FRONT. OCCASIONAL
MVFR VIS ARE POSSIBLE OVERNIGHT DURING RAIN.
BEHIND THE FRONT...MUCH DRIER AIR AND VFR CONDITIONS BUILD IN
QUICKLY FROM THE WEST AFTER 10Z. GUSTY SURFACE WINDS WILL BECOME
THE PRIMARY WEATHER CONCERN FOR AIRCRAFT ON MON...WITH SUSTAINED
WINDS AT 20-25 KTS AND GUSTS TO ARND 40 KTS...PARTICULARLY IVOF SBY.
HIGH PRESSURE CONTINUES TO BUILD IN MON NIGHT AND
TUE...VFR CONDITIONS CONTINUE WITH DIMINISHING WIND SPEEDS. NEXT
CHANCE FOR REDUCED CIGS/VSBYS WILL BE WED/WED NIGHT WITH AREAS OF
PCPN (POSSIBLY SNOW OR A MIX OVER NRN SITES) ASSOCIATED WITH A
FAST MOVING CLIPPER SYSTEM.
&&
.MARINE...
STRONG GALES CONDS EXPECTED OVR THE WATERS FOR VERY LATE
TONIGHT(EARLY MON MORN) THRU AS LATE AS TUE MORN...AS AN AREA OF
LOW PRES MVS FROM THE GREAT LAKES TOWARD NEW ENGLAND AND DRAGS A
SAGGING CD FRNT THRU THE MID ATLC REGION...WHICH MVS OFFSHORE BY
LATE MON AFTN. ALONG WITH THE HIGHER WINDS JUST AHEAD AND ALONG W/
THE FRONT...EXPECT STRONG CAA POST FROPA...WHICH IS WHY THE GALE
HEADLINES HAV BEEN EXTENDED THRU TUE MORN IN ORDER TO COVER. HV
UPDATED HEADLINES TO DROP SCA AND GO WITH HIGHER PRIORITY HEADLINE
OF GALE WARNING.
MARINE AREA MAY HV A BRIEF BREAK IN THE ACTION LATE TUE INTO EARLY
WED...BEFORE ANOTHER CD FRNT MVS ACROSS THE WATERS BY MID WEEK,
POSSIBLY BRINGING MORE MARINE HEADLINES TO THE WTRS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR
MDZ021>025.
NC...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR NCZ102.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR NCZ102.
VA...WIND ADVISORY FROM 7 AM MONDAY TO 1 AM EST TUESDAY FOR
VAZ075>078-099-100.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ650-652-654-656-658.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR ANZ650-
652-654-656-658.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 8 AM EST MONDAY
FOR ANZ630>632.
GALE WARNING FROM 8 AM MONDAY TO 5 AM EST TUESDAY FOR
ANZ630>633.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 8 AM EST
MONDAY FOR ANZ633.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...MAM
LONG TERM...MAM/CCW
AVIATION...BAJ
MARINE...SMF
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
105 PM EST SUN DEC 2 2007
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE FROM THE UPPER MIDWEST
INTO NEW ENGLAND TODAY...WITH A TRAILING COLD FRONT PUSHING OFF
THE EAST COAST BY MONDAY AFTERNOON. A FRONTAL BOUNDARY WILL
CONTINUE TO BE DRAPED ACROSS THE REGION AS A SERIES OF SHORTWAVES
MOVE WEST TO EAST ALONG IT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE ONLY MINOR ADJUSTMENTS TO T GRIDS FOR THIS
AFTERNOON...ADJUSTING DOWNWARD SLIGHTLY AS PER LATEST TRENDS. HAVE
ADJUSTED POPS TO ALLOW FOR SCT/ISO SHRAS WORDING THIS AFTN (AND
REDUCING TO SILENT POPS OVER NC COUNTIES THRU THIS AFTN. RAIN WL
INCREASE IN AREAL COVG/INTENSITY BY LATE THIS AFTN/ERY
EVENING...PARTICULARLY OVER NORTHERN HALF OF CWA.
NEXT FORECAST CHALLENGE WL BE IN TIMING FRONT ITSELF AND THEN
DIAGNOSING DEGREE OF WNDS MONDAY.
&&
.SHORT TERM /MONDAY/...
FOLLOWING CLOSE TO GFS FOR THIS FCST PACKAGE.
LOOK FOR -RA TO DEVELOP NW/SE LATE THIS AFTN AS H92 MOISTURE
TRANSPORT VECTORS DO NOT INCREASE TILL AROUND 21Z. HIGHEST LVLS OF
MOISTURE TRANSPORT LOOK TO OCCUR OVERNIGHT (00Z-09Z MON) OVER THE
CWA NW/SE. NAM12 H92 Q-VECTORS CONVERGENCE ZONE DVLPS 03-09Z
(NW/SE) OVER THE CWA AND THINK THIS IS THE BEST WINDOW OF WHEN
ACCUMULATING PRECIP WILL OCCUR. CURRENTLY THINK MOST AREAS WILL
SEE AN AVG OF 0.25 INCHES OF RAIN...WITH LOCALLY HIGHER/LOWER AMTS
POSSIBLE. DRY AIR QUICKLY MOVES INTO THE REGION AT LOW/MID LVLS
BEHIND FRONTAL PASS TWRDS 12Z MON. WILL KEEP MENTION OF PRECIP
OVER ERN THIRD THROUGH MID AM.
AFTER FRONTAL PASS BREEZY TO WINDY CONDITIONS WILL DEVELOP. FCST
SNGDS CONTINUE TO SHOW VERY GOOD MOMENTUM TRANSFER OVER NE CWA ON
MON (STRONGER WINDS ALOFT ARE ABLE TO REACH SFC). WILL GENERALLY
SEE WIND GUSTS AROUND 40 MPH OVER THE ERN SHORE (WOULD NOT BE
SURPRISED TO SEE A GUST TO 50 MPH RECORDED). REST OF CWA WILL
GENERALLY SEE GUSTS AROUND 30 MPH THROUGH MON AFTN BEFORE GRADIENT
RELAXES.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
ATTENTION THEN TURNS TO GFS/ECMWF SOLNS TUE EVE/OVRNT AS
AFOREMENTIONED COLD FRONT LIFTS BACK NORTHWARD OVER THE REGION AS A
SHORTWV RIDES W/E ALONG IT FROM THE OHIO VLY. GFS BUFKIT SNGS SHOW
MID LVLS SATURATING (H85-50) ABV 90% OVER THE NRN HALF OF
THE CWA (MAINLY AROUND 03Z TUE). THINK THIS WILL BE A COOLING
SITUATION WHERE NOT ONLY DOES SATURATION QUICKLY DEVELOP AT LOW
LVLS...BUT EVAPORATIVE COOLING WILL DROP TEMPS NEAR THE SFC TO/BLO
THE FRZG MARK. THIS WILL MAKE FOR PRECIP TYPE CHALLENGES TUE NIGHT
AND INTO WED BEFORE TEMPS WARM ENOUGH TO BECOME ALL RAIN. STILL TOO
FAR OUT TO GET TO SPECIFIC ON POSSIBLE SNOW ACCUMS...BUT BEST CHC FOR
SNOW WILL BE OVER NORTHERN THIRD OF THE CWA. MRYLD ERN SHORE MORE
COMPLICATED TUE NIGHT AS ANY ERLY FLOW (MARINE INFLUENCE) MAY ALLOW
FOR A QUICKER TRANSITION TO ALL RAIN...BUT CAN FINE TUNE IN LATER
FCSTS.
WILL CONTINUE WITH POPS OVER NRN THIRD THROUGH THE DAYTIME WED AS
-RA/DZ CONTINUING AS FRONTAL BOUNDARY CONTINUES TO DRAPE OVER THE
REGION.
SECONDARY AND MORE POTENT SHRTWV ASSOCD WITH A CLIPPER SYSTEM WILL
DIVE SOUTHWARD FROM CNTRL CANADA AND MEET UP WITH A SHRTWV (EJECTED
FROM THE PAC NW) OVER THE NRN PLAINS TUE. THIS WILL BRING ANOTHER
ROUND OF PRECIP TYPE CHALLENGES WED NIGHT INTO THU. NO CHANGES
BEYOND 12Z THU THIS FCST PACKAGE.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
LOW PRESSURE SYSTEM WILL CROSS THE GREAT LAKES OVERNIGHT AND
EARLY MON. COLD FRONT TRAILING S/SW FROM THE LOW WILL APPROACHES THE
REGION TODAY...THEN CROSSES THE AREA LATE TONIGHT AND EARLY ON MON.
MID/UPPER LEVEL CLOUD DECKS DEVELOPED OVER THE SRN SITES THIS
MORNING. ANTICIPATE REMAINING VFR CONDITIONS TO GIVE WAY TO MVFR
CIGS DURING THE EVENING AND OVERNIGHT HOURS...COINCIDING WITH THE
AXIS OF MAXIMUM LLVL MOISTURE AND AREAS OF SHOWERS ALONG/AHEAD OF
THE FRONT. OCCASIONAL MVFR VIS ARE POSSIBLE OVERNIGHT DURING RAIN.
BEHIND THE FRONT...MUCH DRIER AIR AND VFR CONDITIONS BUILD IN
QUICKLY FROM THE WEST AFTER 10Z. GUSTY SURFACE WINDS WILL BECOME
THE PRIMARY WEATHER CONCERN FOR AIRCRAFT ON MON...WITH SUSTAINED
WINDS AT 20-25 KTS AND GUSTS TO NEAR 40 KTS...PARTICULARLY FOR
NERN TAF SITES.
HIGH PRESSURE CONTINUES TO BUILD IN MON NIGHT AND
TUE...VFR CONDITIONS CONTINUE WITH DIMINISHING WIND SPEEDS. NEXT
CHANCE FOR REDUCED CIGS/VSBYS WILL BE WED/WED NIGHT WITH AREAS OF
PCPN (POSSIBLY SNOW OR A MIX OVER NRN SITES) ASSOCIATED WITH A
FAST MOVING CLIPPER SYSTEM.
&&
.MARINE...
PRE-COLD FRONTAL SURGE WILL KICK START ANOTHER ROUND OF SMALL CRAFT
ADVISORIES (SCA`S) THIS EVENING AND OVERNIGHT. THEN...AS PER
PREVIOUS FCSTS...EXPECT SOLID GALES TO DEVELOP DURING THE DAYLIGHT
HOURS MON WITH THE STRONG LLVL CAA/NW SURGE BEHIND THE FRONT. EXPECT
THE STRONGEST WINDS (GUSTS NEAR STORM FORCE) AND SEAS OVER THE NRN
CSTL WATERS...GIVEN THE STRONGER PRESSURE GRADIENT NOTED WITH THE
LOW PRESSURE SYSTEM DEEPENING RAPIDLY ALONG THE NEW ENGLAND COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR NCZ102.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR NCZ102.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ650-652-654-656-658.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR ANZ650-
652-654-656-658.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY
FOR ANZ630>632.
GALE WARNING FROM 9 AM TO 8 PM EST MONDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 AM EST
TUESDAY FOR ANZ633.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...CCW
LONG TERM...CCW/MAM
AVIATION...BKH/BAJ
MARINE...BKH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1054 AM EST SUN DEC 2 2007
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE FROM THE UPPER MIDWEST
INTO NEW ENGLAND TODAY...WITH A TRAILING COLD FRONT PUSHING OFF
THE EAST COAST BY MONDAY AFTERNOON. A FRONTAL BOUNDARY WILL
CONTINUE TO BE DRAPED ACROSS THE REGION AS A SERIES OF SHORTWAVES
MOVE WEST TO EAST ALONG IT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE ONLY MINOR ADJUSTMENTS TO T GRIDS FOR THIS
AFTERNOON...ADJUSTING DOWNWARD SLIGHTLY AS PER LATEST TRENDS. HAVE
ADJUSTED POPS TO ALLOW FOR SCT/ISO SHRAS WORDING THIS AFTN (AND
REDUCING TO SILENT POPS OVER NC COUNTIES THRU THIS AFTN. RAIN WL
INCREASE IN AREAL COVG/INTENSITY BY LATE THIS AFTN/ERY
EVENING...PARTICULARLY OVER NORTHERN HALF OF CWA.
NEXT FORECAST CHALLENGE WL BE IN TIMING FRONT ITSELF AND THEN
DIAGNOSING DEGREE OF WNDS MONDAY.
&&
.SHORT TERM /MONDAY/...
FOLLOWING CLOSE TO GFS FOR THIS FCST PACKAGE.
LOOK FOR -RA TO DEVELOP NW/SE LATE THIS AFTN AS H92 MOISTURE
TRANSPORT VECTORS DO NOT INCREASE TILL AROUND 21Z. HIGHEST LVLS OF
MOISTURE TRANSPORT LOOK TO OCCUR OVERNIGHT (00Z-09Z MON) OVER THE
CWA NW/SE. NAM12 H92 Q-VECTORS CONVERGENCE ZONE DVLPS 03-09Z
(NW/SE) OVER THE CWA AND THINK THIS IS THE BEST WINDOW OF WHEN
ACCUMULATING PRECIP WILL OCCUR. CURRENTLY THINK MOST AREAS WILL
SEE AN AVG OF 0.25 INCHES OF RAIN...WITH LOCALLY HIGHER/LOWER AMTS
POSSIBLE. DRY AIR QUICKLY MOVES INTO THE REGION AT LOW/MID LVLS
BEHIND FRONTAL PASS TWRDS 12Z MON. WILL KEEP MENTION OF PRECIP
OVER ERN THIRD THROUGH MID AM.
AFTER FRONTAL PASS BREEZY TO WINDY CONDITIONS WILL DEVELOP. FCST
SNGDS CONTINUE TO SHOW VERY GOOD MOMENTUM TRANSFER OVER NE CWA ON
MON (STRONGER WINDS ALOFT ARE ABLE TO REACH SFC). WILL GENERALLY
SEE WIND GUSTS AROUND 40 MPH OVER THE ERN SHORE (WOULD NOT BE
SURPRISED TO SEE A GUST TO 50 MPH RECORDED). REST OF CWA WILL
GENERALLY SEE GUSTS AROUND 30 MPH THROUGH MON AFTN BEFORE GRADIENT
RELAXES.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ATTENTION THEN TURNS TO GFS/ECMWF SOLNS TUE EVE/OVRNT AS
AFOREMENTIONED COLD FRONT LIFTS BACK NORTHWARD OVER THE REGION AS A
SHORTWV RIDES W/E ALONG IT FROM THE OHIO VLY. GFS BUFKIT SNGS SHOW
MID LVLS SATURATING (H85-50) ABV 90% OVER THE NRN HALF OF
THE CWA (MAINLY AROUND 03Z TUE). THINK THIS WILL BE A COOLING
SITUATION WHERE NOT ONLY DOES SATURATION QUICKLY DEVELOP AT LOW
LVLS...BUT EVAPORATIVE COOLING WILL DROP TEMPS NEAR THE SFC TO/BLO
THE FRZG MARK. THIS WILL MAKE FOR PRECIP TYPE CHALLENGES TUE NIGHT
AND INTO WED BEFORE TEMPS WARM ENOUGH TO BECOME ALL RAIN. STILL TOO
FAR OUT TO GET TO SPECIFIC ON POSSIBLE SNOW ACCUMS...BUT BEST CHC FOR
SNOW WILL BE OVER NORTHERN THIRD OF THE CWA. MRYLD ERN SHORE MORE
COMPLICATED TUE NIGHT AS ANY ERLY FLOW (MARINE INFLUENCE) MAY ALLOW
FOR A QUICKER TRANSITION TO ALL RAIN...BUT CAN FINE TUNE IN LATER
FCSTS.
WILL CONTINUE WITH POPS OVER NRN THIRD THROUGH THE DAYTIME WED AS
-RA/DZ CONTINUING AS FRONTAL BOUNDARY CONTINUES TO DRAPE OVER THE
REGION.
SECONDARY AND MORE POTENT SHRTWV ASSOCD WITH A CLIPPER SYSTEM WILL
DIVE SOUTHWARD FROM CNTRL CANADA AND MEET UP WITH A SHRTWV (EJECTED
FROM THE PAC NW) OVER THE NRN PLAINS TUE. THIS WILL BRING ANOTHER
ROUND OF PRECIP TYPE CHALLENGES WED NIGHT INTO THU. NO CHANGES
BEYOND 12Z THU THIS FCST PACKAGE.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
LOW PRESSURE SYSTEM WILL CONTINUE TO CROSS THE UPPER MIDWEST REGION
TODAY...THEN TRACK THROUGH THE EASTERN GREAT LAKES OVERNIGHT AND
EARLY MON. COLD FRONT TRAILING S/SW FRONT THE LOW WILL APPROACH THE
REGION TODAY...THEN CROSS THE AREA LATE TONIGHT AND EARLY ON MON.
MID/UPPER LEVEL CLOUD DECKS WILL CONTINUE TO BUILD IN THIS MORNING
AND AFTN. ANTICIPATE VFR CONDITIONS TO GIVE WAY TO MVFR CIGS AND
VSBYS DURING THE EVENING AND OVERNIGHT HOURS...COINCIDING WITH THE
AXIS OF MAXIMUM LLVL MOISTURE AND AREAS OF SHOWERS ALONG/AHEAD OF
THE FRONT. PATCHY IFR CONDITIONS ARE ALSO POSSIBLE OVERNIGHT.
BEHIND THE FRONT...MUCH DRIER AIR BUILDS IN QUICKLY FROM THE WEST
DURING THE DAYLIGHT HOURS ON MON. GUSTY SURFACE WINDS WILL BECOME
THE PRIMARY WEATHER CONCERN FOR AIRCRAFT ON MON...WITH SUSTAINED
WINDS AT 20-25 KTS AND GUSTS TO NEAR 40 KTS. HIGH PRESSURE CONTINUES
TO BUILD IN MON NIGHT AND TUE...MAINTAINING THE VFR CONDITIONS ALONG
WITH DIMINISHING WIND SPEEDS. NEXT CHANCE FOR REDUCED CIGS/VSBYS
WILL BE NEXT WED/WED NIGHT WITH AREAS OF PCPN (POSSIBLY SNOW OR A
MIX OVER NRN SITES) ASSOCIATED WITH A FAST MOVING CLIPPER SYSTEM.
&&
.MARINE...
PRE-COLD FRONTAL SURGE WILL KICK START ANOTHER ROUND OF SMALL CRAFT
ADVISORIES (SCA`S) THIS EVENING AND OVERNIGHT. THEN...AS PER
PREVIOUS FCSTS...EXPECT SOLID GALES TO DEVELOP DURING THE DAYLIGHT
HOURS MON WITH THE STRONG LLVL CAA/NW SURGE BEHIND THE FRONT. EXPECT
THE STRONGEST WINDS (GUSTS NEAR STORM FORCE) AND SEAS OVER THE NRN
CSTL WATERS...GIVEN THE STRONGER PRESSURE GRADIENT NOTED WITH THE
LOW PRESSURE SYSTEM DEEPENING RAPIDLY ALONG THE NEW ENGLAND COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR NCZ102.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR NCZ102.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ650-652-654-656-658.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR ANZ650-
652-654-656-658.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY
FOR ANZ630>632.
GALE WARNING FROM 9 AM TO 8 PM EST MONDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 AM EST
TUESDAY FOR ANZ633.
&&
$$
SYNOPSIS...MAM/CCW
NEAR TERM...MAM
SHORT TERM...CCW
LONG TERM...CCW/MAM
AVIATION...BKH
MARINE...BKH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
651 AM EST SUN DEC 2 2007
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE FROM THE UPPER MIDWEST
INTO NEW ENGLAND TODAY...WITH A TRAILING COLD FRONT PUSHING OFF
THE EAST COAST BY MONDAY AFTERNOON. A FRONTAL BOUNDARY WILL
CONTINUE TO BE DRAPED ACROSS THE REGION AS A SERIES OF SHORTWAVES
MOVE WEST TO EAST ALONG IT.
&&
.NEAR TERM /UNTIL 4 PM THIS AFTERNOON/...
DRY CONDITIONS PREVAIL FOR THE MORNING AND INTO ERLY AFTN AHEAD
OF APPROACHING SYSTEM.
&&
.SHORT TERM /4 PM THIS AFTERNOON THROUGH 6 PM MONDAY/...
FOLLOWING CLOSE TO GFS FOR THIS FCST PACKAGE.
LOOK FOR -RA TO DEVELOP NW/SE LATE THIS AFTN AS H92 MOISTURE
TRANSPORT VECTORS DO NOT INCREASE TILL AROUND 21Z. HIGHEST LVLS OF
MOISTURE TRANSPORT LOOK TO OCCUR OVERNIGHT (00Z-09Z MON) OVER THE
CWA NW/SE. NAM12 H92 Q-VECTORS CONVERGENCE ZONE DVLPS 03-09Z
(NW/SE) OVER THE CWA AND THINK THIS IS THE BEST WINDOW OF WHEN
ACCUMULATING PRECIP WILL OCCUR. CURRENTLY THINK MOST AREAS WILL
SEE AN AVG OF 0.25 INCHES OF RAIN...WITH LOCALLY HIGHER/LOWER AMTS
POSSIBLE. DRY AIR QUICKLY MOVES INTO THE REGION AT LOW/MID LVLS
BEHIND FRONTAL PASS TWRDS 12Z MON. WILL KEEP MENTION OF PRECIP
OVER ERN THIRD THROUGH MID AM.
AFTER FRONTAL PASS BREEZY TO WINDY CONDITIONS WILL DEVELOP. FCST
SNGDS CONTINUE TO SHOW VERY GOOD MOMENTUM TRANSFER OVER NE CWA ON
MON (STRONGER WINDS ALOFT ARE ABLE TO REACH SFC). WILL GENERALLY
SEE WIND GUSTS AROUND 40 MPH OVER THE ERN SHORE (WOULD NOT BE
SURPRISED TO SEE A GUST TO 50 MPH RECORDED). REST OF CWA WILL
GENERALLY SEE GUSTS AROUND 30 MPH THROUGH MON AFTN BEFORE GRADIENT
RELAXES.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ATTENTION THEN TURNS TO GFS/ECMWF SOLNS TUE EVE/OVRNT AS
AFOREMENTIONED COLD FRONT LIFTS BACK NORTHWARD OVER THE REGION AS A
SHORTWV RIDES W/E ALONG IT FROM THE OHIO VLY. GFS BUFKIT SNGS SHOW
MID LVLS SATURATING (H85-50) ABV 90% OVER THE NRN HALF OF
THE CWA (MAINLY AROUND 03Z TUE). THINK THIS WILL BE A COOLING
SITUATION WHERE NOT ONLY DOES SATURATION QUICKLY DEVELOP AT LOW
LVLS...BUT EVAPORATIVE COOLING WILL DROP TEMPS NEAR THE SFC TO/BLO
THE FRZG MARK. THIS WILL MAKE FOR PRECIP TYPE CHALLENGES TUE NIGHT
AND INTO WED BEFORE TEMPS WARM ENOUGH TO BECOME ALL RAIN. STILL TOO
FAR OUT TO GET TO SPECIFIC ON POSSIBLE SNOW ACCUMS...BUT BEST CHC FOR
SNOW WILL BE OVER NORTHERN THIRD OF THE CWA. MRYLD ERN SHORE MORE
COMPLICATED TUE NIGHT AS ANY ERLY FLOW (MARINE INFLUENCE) MAY ALLOW
FOR A QUICKER TRANSITION TO ALL RAIN...BUT CAN FINE TUNE IN LATER
FCSTS.
WILL CONTINUE WITH POPS OVER NRN THIRD THROUGH THE DAYTIME WED AS
-RA/DZ CONTINUING AS FRONTAL BOUNDARY CONTINUES TO DRAPE OVER THE
REGION.
SECONDARY AND MORE POTENT SHRTWV ASSOCD WITH A CLIPPER SYSTEM WILL
DIVE SOUTHWARD FROM CNTRL CANADA AND MEET UP WITH A SHRTWV (EJECTED
FROM THE PAC NW) OVER THE NRN PLAINS TUE. THIS WILL BRING ANOTHER
ROUND OF PRECIP TYPE CHALLENGES WED NIGHT INTO THU. NO CHANGES
BEYOND 12Z THU THIS FCST PACKAGE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
LOW PRESSURE SYSTEM WILL CONTINUE TO CROSS THE UPPER MIDWEST REGION
TODAY...THEN TRACK THROUGH THE EASTERN GREAT LAKES OVERNIGHT AND
EARLY MON. COLD FRONT TRAILING S/SW FRONT THE LOW WILL APPROACH THE
REGION TODAY...THEN CROSS THE AREA LATE TONIGHT AND EARLY ON MON.
MID/UPPER LEVEL CLOUD DECKS WILL CONTINUE TO BUILD IN THIS MORNING
AND AFTN. ANTICIPATE VFR CONDITIONS TO GIVE WAY TO MVFR CIGS AND
VSBYS DURING THE EVENING AND OVERNIGHT HOURS...COINCIDING WITH THE
AXIS OF MAXIMUM LLVL MOISTURE AND AREAS OF SHOWERS ALONG/AHEAD OF
THE FRONT. PATCHY IFR CONDITIONS ARE ALSO POSSIBLE OVERNIGHT.
BEHIND THE FRONT...MUCH DRIER AIR BUILDS IN QUICKLY FROM THE WEST
DURING THE DAYLIGHT HOURS ON MON. GUSTY SURFACE WINDS WILL BECOME
THE PRIMARY WEATHER CONCERN FOR AIRCRAFT ON MON...WITH SUSTAINED
WINDS AT 20-25 KTS AND GUSTS TO NEAR 40 KTS. HIGH PRESSURE CONTINUES
TO BUILD IN MON NIGHT AND TUE...MAINTAINING THE VFR CONDITIONS ALONG
WITH DIMINISHING WIND SPEEDS. NEXT CHANCE FOR REDUCED CIGS/VSBYS
WILL BE NEXT WED/WED NIGHT WITH AREAS OF PCPN (POSSIBLY SNOW OR A
MIX OVER NRN SITES) ASSOCIATED WITH A FAST MOVING CLIPPER SYSTEM.
&&
.MARINE...
PRE-COLD FRONTAL SURGE WILL KICK START ANOTHER ROUND OF SMALL CRAFT
ADVISORIES (SCA`S) THIS EVENING AND OVERNIGHT. THEN...AS PER
PREVIOUS FCSTS...EXPECT SOLID GALES TO DEVELOP DURING THE DAYLIGHT
HOURS MON WITH THE STRONG LLVL CAA/NW SURGE BEHIND THE FRONT. EXPECT
THE STRONGEST WINDS (GUSTS NEAR STORM FORCE) AND SEAS OVER THE NRN
CSTL WATERS...GIVEN THE STRONGER PRESSURE GRADIENT NOTED WITH THE
LOW PRESSURE SYSTEM DEEPENING RAPIDLY ALONG THE NEW ENGLAND COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR NCZ102.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR NCZ102.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ650-652-654-656-658.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR ANZ650-
652-654-656-658.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY
FOR ANZ630>632.
GALE WARNING FROM 9 AM TO 8 PM EST MONDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 AM EST
TUESDAY FOR ANZ633.
&&
$$
SYNOPSIS...CCW
NEAR TERM...CCW
SHORT TERM...CCW
LONG TERM...CCW/MAM
AVIATION...BKH
MARINE...BKH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
407 AM EST SUN DEC 2 2007
.SYNOPSIS...
A STRONG AREA OF LOW PRESSURE WILL MOVE FROM THE UPPER MIDWEST
INTO NEW ENGLAND TODAY...WITH A TRAILING COLD FRONT PUSHING OFF
THE EAST COAST BY MONDAY AFTERNOON. A FRONTAL BOUNDARY WILL
CONTINUE TO BE DRAPED ACROSS THE REGION AS A SERIES OF SHORTWAVES
MOVE WEST TO EAST ALONG IT.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
INITIAL BATCH OF PRECIP MOVG OVER MD ERN SHORE EARLY THIS AM (BEFORE
12Z) WITH WARM FRONT LIFTING NORTH AND SOME -PL MAY MIX IN WITH
ANYTHING THAT REACHES THE SFC.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM MONDAY/...
AFTER 12Z...DRY CONDITIONS PREVAIL FOR THE MORNING AND INTO ERLY
AFTN AHEAD OF APPROACHING SYSTEM.
FOLLOWING CLOSE TO GFS FOR THIS FCST PACKAGE.
LOOK FOR -RA TO DEVELOP NW/SE LATE THIS AFTN AS H92 MOISTURE
TRANSPORT VECTORS DO NOT INCREASE TILL AROUND 21Z. HIGHEST LVLS OF
MOISTURE TRANSPORT LOOK TO OCCUR OVERNIGHT (00Z-09Z MON) OVER THE
CWA NW/SE. NAM12 H92 Q-VECTORS CONVERGENCE ZONE DVLPS 03-09Z
(NW/SE) OVER THE CWA AND THINK THIS IS THE BEST WINDOW OF WHEN
ACCUMULATING PRECIP WILL OCCUR. CURRENTLY THINK MOST AREAS WILL
SEE AN AVG OF 0.25 INCHES OF RAIN...WITH LOCALLY HIGHER/LOWER AMTS
POSSIBLE. DRY AIR QUICKLY MOVES INTO THE REGION AT LOW/MID LVLS
BEHIND FRONTAL PASS TWRDS 12Z MON. WILL KEEP MENTION OF PRECIP
OVER ERN THIRD THROUGH MID AM.
AFTER FRONTAL PASS BREEZY TO WINDY CONDITIONS WILL DEVELOP. FCST
SNGDS CONTINUE TO SHOW VERY GOOD MOMENTUM TRANSFER OVER NE CWA ON
MON (STRONGER WINDS ALOFT ARE ABLE TO REACH SFC). WILL GENERALLY
SEE WIND GUSTS AROUND 40 MPH OVER THE ERN SHORE (WOULD NOT BE
SURPRISED TO SEE A GUST TO 50 MPH RECORDED). REST OF CWA WILL
GENERALLY SEE GUSTS AROUND 30 MPH THROUGH MON AFTN BEFORE GRADIENT
RELAXES.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ATTENTION THEN TURNS TO GFS/ECMWF SOLNS TUE EVE/OVRNT AS
AFOREMENTIONED COLD FRONT LIFTS BACK NORTHWARD OVER THE REGION AS A
SHORTWV RIDES W/E ALONG IT FROM THE OHIO VLY. GFS BUFKIT SNGS SHOW
MID LVLS SATURATING (H85-50) ABV 90% OVER THE NRN HALF OF
THE CWA (MAINLY AROUND 03Z TUE). THINK THIS WILL BE A COOLING
SITUATION WHERE NOT ONLY DOES SATURATION QUICKLY DEVELOP AT LOW
LVLS...BUT EVAPORATIVE COOLING WILL DROP TEMPS NEAR THE SFC TO/BLO
THE FRZG MARK. THIS WILL MAKE FOR PRECIP TYPE CHALLENGES TUE NIGHT
AND INTO WED BEFORE TEMPS WARM ENOUGH TO BECOME ALL RAIN. STILL TOO
FAR OUT TO GET TO SPECIFIC ON POSSIBLE SNOW ACCUMS...BUT BEST CHC FOR
SNOW WILL BE OVER NORTHERN THIRD OF THE CWA. MRYLD ERN SHORE MORE
COMPLICATED TUE NIGHT AS ANY ERLY FLOW (MARINE INFLUENCE) MAY ALLOW
FOR A QUICKER TRANSITION TO ALL RAIN...BUT CAN FINE TUNE IN LATER
FCSTS.
WILL CONTINUE WITH POPS OVER NRN THIRD THROUGH THE DAYTIME WED AS
-RA/DZ CONTINUING AS FRONTAL BOUNDARY CONTINUES TO DRAPE OVER THE
REGION.
SECONDARY AND MORE POTENT SHRTWV ASSOCD WITH A CLIPPER SYSTEM WILL
DIVE SOUTHWARD FROM CNTRL CANADA AND MEET UP WITH A SHRTWV (EJECTED
FROM THE PAC NW) OVER THE NRN PLAINS TUE. THIS WILL BRING ANOTHER
ROUND OF PRECIP TYPE CHALLENGES WED NIGHT INTO THU. NO CHANGES
BEYOND 12Z THU THIS FCST PACKAGE.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
LOW PRESSURE SYSTEM WILL CONTINUE TO CROSS THE UPPER MIDWEST REGION
TODAY...THEN TRACK THROUGH THE EASTERN GREAT LAKES OVERNIGHT AND
EARLY MON. COLD FRONT TRAILING S/SW FRONT THE LOW WILL APPROACH THE
REGION TODAY...THEN CROSS THE AREA LATE TONIGHT AND EARLY ON MON.
MID/UPPER LEVEL CLOUD DECKS WILL CONTINUE TO BUILD IN THIS MORNING
AND AFTN. ANTICIPATE VFR CONDITIONS TO GIVE WAY TO MVFR CIGS AND
VSBYS DURING THE EVENING AND OVERNIGHT HOURS...COINCIDING WITH THE
AXIS OF MAXIMUM LLVL MOISTURE AND AREAS OF SHOWERS ALONG/AHEAD OF
THE FRONT. PATCHY IFR CONDITIONS ARE ALSO POSSIBLE OVERNIGHT.
BEHIND THE FRONT...MUCH DRIER AIR BUILDS IN QUICKLY FROM THE WEST
DURING THE DAYLIGHT HOURS ON MON. GUSTY SURFACE WINDS WILL BECOME
THE PRIMARY WEATHER CONCERN FOR AIRCRAFT ON MON...WITH SUSTAINED
WINDS AT 20-25 KTS AND GUSTS TO NEAR 40 KTS. HIGH PRESSURE CONTINUES
TO BUILD IN MON NIGHT AND TUE...MAINTAINING THE VFR CONDITIONS ALONG
WITH DIMINISHING WIND SPEEDS. NEXT CHANCE FOR REDUCED CIGS/VSBYS
WILL BE NEXT WED/WED NIGHT WITH AREAS OF PCPN (POSSIBLY SNOW OR A
MIX OVER NRN SITES) ASSOCIATED WITH A FAST MOVING CLIPPER SYSTEM.
&&
.MARINE...
PRE-COLD FRONTAL SURGE WILL KICK START ANOTHER ROUND OF SMALL CRAFT
ADVISORIES (SCA`S) THIS EVENING AND OVERNIGHT. THEN...AS PER
PREVIOUS FCSTS...EXPECT SOLID GALES TO DEVELOP DURING THE DAYLIGHT
HOURS MON WITH THE STRONG LLVL CAA/NW SURGE BEHIND THE FRONT. EXPECT
THE STRONGEST WINDS (GUSTS NEAR STORM FORCE) AND SEAS OVER THE NRN
CSTL WATERS...GIVEN THE STRONGER PRESSURE GRADIENT NOTED WITH THE
LOW PRESSURE SYSTEM DEEPENING RAPIDLY ALONG THE NEW ENGLAND COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR NCZ102.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR NCZ102.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR ANZ650-652-654-656-658.
GALE WARNING FROM 6 AM MONDAY TO 5 AM EST TUESDAY FOR ANZ650-
652-654-656-658.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY
FOR ANZ630>632.
GALE WARNING FROM 9 AM TO 8 PM EST MONDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 AM EST
TUESDAY FOR ANZ633.
&&
$$
SYNOPSIS...CCW
NEAR TERM...CCW
SHORT TERM...CCW
LONG TERM...CCW/MAM
AVIATION...BKH
MARINE...BKH
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1003 PM EST MON DEC 3 2007
.UPDATE...
MAIN FCST ISSUE OVERNIGHT IS SNOW ACCUMULATIONS AS LES CONTINUES.
SFC HIGH PRES HAS BEEN GRADUALLY BUILDING SE INTO NRN ONTARIO DURING
THE AFTN/EVENING...AND LOW-LEVEL WIND FIELD IS RESPONDING. KMQT VAD
WIND PROFILE HAS SHOWN A 340 MEAN CONVECTIVE BOUNDARY LAYER FLOW
THIS AFTN VEERING TO 360 THIS EVENING. AS A RESULT...KMQT RADAR
IMAGERY SHOWED NNW-SSE ALIGNED WIND PARALLEL LES BANDS SHIFTING W.
BANDS HAVE RECENTLY LOST ORGANIZATION THOUGH DUE TO THE VEERING
WINDS...BUT PROBABLY MORE LIKELY DUE TO THE DIVERGENT WIND FIELD
OVER THE N PART OF THE LAKE NOW (NE WINDS FROM ISLE ROYALE TO THE
KEWEENAW AND N WINDS OVER THE ERN PART OF THE LAKE).
UPDATED FCST EARLIER THIS EVENING TO BUMP UP SNOW ACCUMULATIONS
(LOCALLY UP TO 4 INCHES) OVER THE NCNTRL DUE TO THE VERY HIGH SNOW
TO WATER RATIO WHICH IS LEADING TO QUICK ACCUMULATIONS OF FLUFF
WITHIN LES BANDS. OVER THE ERN PART OF LAKE SUPERIOR...WINDS HAVE
VEERED ABOUT AS MUCH AS THEY WILL TONIGHT PER 00Z RUC. THIS RAISES
SOME CONCERN ABOUT THE NEED FOR AN ADVY FOR MARQUETTE/ALGER COUNTIES
AS BANDS TRY TO REORGANIZE UNDER WHAT WILL BE A PERSISTENT 360 FLOW.
LONG N-S FETCH ACROSS THE LAKE AND THE OBVIOUS FAVORABLE DENDRITIC
SNOW GROWTH TEMPS WITHIN THE CONVECTIVE BOUNDARY LAYER SUPPORT A
POTENTIAL FOR ADVY LEVEL ACCUMULATIONS OF FLUFF. IN ADDITION...LAND
BREEZES WILL ALSO INCREASE THE CONVERGENCE OVER SCNTRL LAKE
SUPERIOR. ON THE OTHER HAND...THE DIRECTIONAL DIVERGENCE OVER THE N
END OF THE LAKE WILL PERSIST AND MAY WORK TO KEEP BANDS FROM
BECOMING WELL ORGANIZED. HAVE THUS DECIDED TO HOLD OFF ON AN
ADVY...BUT WILL MENTION TOTAL NIGHTTIME SNOW ACCUMULATIONS UPWARDS
OF 5 INCHES IN ISOLATED SPOTS. IN ANY EVENT...SNOW WILL CERTAINLY BE
LOW IMPACT GIVEN THE HIGH SNOW TO WATER RATIO. TO THE W...THERE WAS
SOME CONCERN FOR A DOMINANT BAND TO DEVELOP DOWN THE W END OF LAKE
SUPERIOR ALONG THE SHORE OF WRN UPPER MI. 00Z RUN OF THE LOCAL HIGH
RES WRF-ARW HAS BACKED OFF ON THIS IDEA OVERNIGHT...BUT IT DOES
EVENTUALLY DEVELOP A DOMINANT BAND OFF THE KEWEENAW STREAMING TO THE
APOSTLE ISLANDS/BAYFIELD PENINSULA TUE INTO TUE EVENING. SINCE LAND
BREEZE WILL LEAD TO INCREASING CONVERGENCE NEAR THE SHORE...WILL
CONTINUE TO KEEP HIGHER POPS IN ONTONAGON/GOGEBIC COUNTIES ALONG THE
SHORE WITH ACCUMULATIONS OF 1 TO LOCALLY 4 INCHES OVERNIGHT.
&&
.PREV DISCUSSION (ISSUED AT 400 PM EST)...
SYNOPSIS...
20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING
OFF THE WEST COAST...RIDGING FROM ALBERTA/SASKATCHEWAN SOUTHWARD
INTO THE DESERT SW...AND TROUGHING OVER THE GREAT LAKES INTO THE
MID-ATLANTIC. BETWEEN THE GREAT LAKES TROUGH AND WESTERN RIDGE...A
140-160KT JET WAS LOCATED NEAR 200MB FROM SASKATCHEWAN THROUGH
SOUTHERN WISCONSIN. THIS JET HAS BEEN TRANSPORTING MOISTURE FROM THE
PACIFIC...NOTED BY MID/HIGH CLOUDS COVERING MUCH OF THE DAKOTAS INTO
MN AND WI...AND NOW THE FAR WESTERN U.P.. WITH THE DOWNSLOPING FLOW
OFF THE ROCKIES...LOW PRESSURE HAS FORMED IN THE WESTERN DAKOTAS.
WARM ADVECTION AHEAD OF THIS LOW IS HELPING TO PRODUCE SOME LIGHT
SNOW OVER MN INTO CENTRAL WI. CLOSER TO HOME...NW FLOW CONTINUES
ACROSS THE GREAT LAKES AROUND LOW PRESSURE IN WESTERN QUEBEC. 850MB
TEMPS OF -12 TO -16C COMBINED WITH SOME MOISTENING OFF LAKE NIPIGON
HAS HELPED TO KEEP LAKE EFFECT SNOW SHOWERS GOING. HOWEVER...THE
INTENSITY HAS DROPPED SINCE THIS MORNING...NOTED BY THE LOSS OF MOST
REFLECTIVITY VALUES ABOVE 24 DBZ. THIS LOSS IS MOSTLY DUE TO THE
LACK OF LAND-BREEZE CONVERGENCE...WHICH USUALLY HAPPENS DURING THE
DAYTIME...IN ADDITION TO LOWERING INVERSIONS (4000 FT ON THE SAW
TAMDAR SOUNDING). WINDS HAVE ALSO BEEN DIMINISHING WITH THE EXIT OF
THE LOW IN WESTERN QUEBEC...WHICH SHOULD BE REDUCING THE BLOWING
SNOW. LAST ITEM TO NOTE IS A SHRTWV TROUGH OVER THE NINAVUT
REGION...WITH 850MB TEMPS AROUND -23C PER 12Z RAOBS.
SHORT TERM (TONIGHT AND TUESDAY)...
UPPER LEVEL PATTERN IS PROGGED TO REMAIN GENERALLY THE SAME THROUGH
TUESDAY...PARTIALLY BECAUSE THE SHRTWV TROUGH OVER THE NINAVUT AREA
IS SHOWN TO DROP SOUTH TOWARDS LAKE SUPERIOR. THUS...VERY LITTLE IF
ANY WARM AIR ADVECTION IS PLANNED DURING THIS PERIOD...MEANING MORE
LAKE EFFECT SNOW. THE ONLY TIME PERIOD WHERE WARM AIR ADVECTION DOES
BECOME SOME FACTOR IS THIS EVENING INTO THE EARLY MORNING HOURS ON
TUESDAY...WHICH IS WHEN THE MID/HIGH CLOUDS WITH SOME LIGHT SNOW ARE
EXPECTED TO MOVE ACROSS. THE MAIN FORECAST CONCERN IS HOW THE LAKE
EFFECT BANDS WILL TRANSITION THEMSELVES. AT THE SURFACE...A HIGH
PRESSURE RIDGE IS EXPECTED TO REMAIN NEARLY STATIONARY FROM THE
NINAVUT REGION INTO NW ONTARIO...AND EVENTUALLY NUDGING DOWN INTO
EASTERN ONTARIO ON TUESDAY AS THE LOW IN QUEBEC MOVES FARTHER AWAY.
MEANWHILE...THE LOW PRESSURE AREA OVER THE DAKOTAS WILL ALSO REMAIN
NEARLY STATIONARY THROUGH TONIGHT...THEN SENT SE ON TUESDAY AS A
SHRTWV MOVES THROUGH THE UPPER FLOW. THE COMBINATION OF THE HIGH AND
LOW PRESSURE AREA TRACKS MEANS THAT THE WINDS SHOULD TURN MORE NORTH
TO NORTHEASTERLY OVER THE NEXT 24 HOURS. 950MB CONVERGENCE FIELDS
FROM THE 12Z NAM AND OUR LOCAL WRF-ARW RUN SUGGESTS THE POSSIBILITY
OF A FAIRLY STRONG BAND (IN PARTICULAR THE WRF-ARW RUN) DEVELOPING
FROM NORTH CENTRAL LAKE SUPERIOR TO AROUND THE SHORELINE OF
ONTONAGON COUNTY AND SW INTO THE SAXON HARBOR AREA. THE ENHANCEMENT
IS A FUNCTION OF BOTH THE LIGHT WARM ADVECTION SNOW MOVING THROUGH
TONIGHT AND LAND-BREEZES CONVERGING ON THE MAIN NE FLOW DOWN WESTERN
LAKE SUPERIOR. HAVE INCREASED POPS AND AMOUNTS NEAR THE SHORE...BUT
STILL KEPT AMOUNTS BELOW ADVISORY AS UNCERTAINTY EXISTS WITH RESPECT
TO BAND PLACEMENT (NAM OFFSHORE AND THE WRF-ARW ONSHORE). EVENING
AND MID-NIGHT SHIFTS WILL NEED TO MONITOR THE LOCATION AND INTENSITY
OF THIS BAND. FARTHER EAST OVER THE NORTH CENTRAL U.P....950MB
CONVERGENCE SUGGESTS MOSTLY MULTI-PARALLEL BANDS WITH OVERALL WEAK
INTENSITY...DUE TO LACK OF ANY SIGNIFICANT LAND-BREEZES AND
INVERSION HEIGHTS REMAINING STUCK BETWEEN 4000-5000 FT. THUS SNOW
ACCUMULATIONS OF 1 TO 3 INCHES PER 12 HOURS SEEMS REASONABLE...WITH
THE GREATEST AMOUNTS OVER THE UPSLOPE AREAS.
REGARDING TEMPS FOR TONIGHT...HAVE BROUGHT THEM UP A COUPLE OF
DEGREES WITH EXPECTED CLOUD COVER MOVING THROUGH...ALONG WITH SOME
SLIGHT WARMING IN THE FLOW OFF SUPERIOR. TEMPS ON TUESDAY SHOULD BE
SIMILAR TO THOSE EXPERIENCED TODAY GIVEN THAT THE AIRMASS IS
SIMILAR.
LONG TERM (TUESDAY NIGHT THROUGH NEXT MON)...
ON TUE NGT...NAM HAS FINALLY COME ARND TO SCENARIO ADVERTISED BY
GFS/UKMET/CNDN IN SHOWING CLIPPER LO DIGGING SEWD FM IA AT 00Z WED
INTO THE OH VALLEY BY 12Z. TRACK OF THIS SYS SUGS BULK OF SYNOPTIC
SCALE PCPN WL FALL S OF THE FA. BUT WL MAINTAIN CHC POPS...HIEST NR
THE WI BORDER...IN AREA WHERE GFS SHOWS LARGER SCALE H85-5 QVECTOR
CNVGC/ H7 UVV AS WELL AS BAND OF H8-7 FGEN WL IMPACT THE AREA.
OTRW...SUSPECT ARRIVAL OF DEEPER MSTR INTO THE BETTER SN GROWTH LYR
AND RISING INVRN HGT ON CYC SIDE OF SHRTWV/H3 JET SUPPORTING CLIPPER
LO AS SHOWN ON NAM/GFS FCST SDNGS WL TEND TO INTENSIFY ONGOING LES
IN THOSE AREAS FVRD BY NNE FLOW. WL GO WITH LIKELY POPS IN THESE
AREAS. LES CHART SUGS 3-6"/12 HR PSBL FOR EXPECTED INVRN HGT RISING
TO ARND 7K FT AND LK-H85 DELTA-T AOA 20C...BUT SHIFTING WINDS DURING
THE NGT MAY REDUCE TOTAL ACCUMULATION. ANOTHER NEGATIVE INFLUENCE WL
BE THE LARGER SCALE DIFFLUENT NEUTRAL-ACYC LLVL FLOW THAT LIMITS
LLVL CNVGC. EVEN SO...WOULD NOT BE SURPRISED IF A MINIMAL ADVY WL BE
NECESSARY IN THE FVRD LOCATIONS. PREFER THE LOWER GFS MOS GUIDANCE
FOR MIN TEMPS
WL END PCPN SYNOPTIC SCALE PCPN CHCS BY 12Z WED TO ACCOUNT FOR
DEPARTURE OF DYNAMICS ASSOCIATED WITH OH VALLEY CLIPPER AND ARRIVAL
OF MID LVL DRYING/H85-5 QVECTOR DVGC AT THAT TIME. OTRW...NEXT
SHRTWV EMBEDDED WITHIN ARCTIC BRANCH NEAR HUDSON BAY IS FCST TO DIG
SSEWD THRU ONTARIO...CAUSING LLVL FLOW OVER THE CWA TO BACK STEADILY
FM N IN THE MRNG TO WNW IN THE AFTN. AS A RESULT...MOST INTENSE LES
BANDS WL SHIFT TO THE WNW WIND FVRD SN BELTS ACRS THE W AND E OF P53
IN THE AFTN. SHARPENING PRES GRADIENT BTWN ARCTIC HI PRES DIGGING
INTO THE UPR MS VALLEY AND FALLING PRES OVER ONTARIO WL CAUSE WINDS
TO INCRS AS WELL...WITH AREAS OF BLSN DVLPG IN THE SN BELTS MOST
EXPOSED TO THE WNW FLOW. TENDED BLO MOS GUIDANCE FOR TEMPS WITH
INVASION OF RATHER SHALLOW ARCTIC AIR SHOWN ON GFS FCST SDNGS. THIS
VERY DRY LLVL AIR (GFS FCST SDNGS FOR CMX SHOW A MORE PRONOUNCED
INVERTED V) AND SHIFTING WINDS WL TEND TO HOLD LES SN TOTALS DOWN A
BIT...SO DON`T FORSEE THE NEED FOR HEADLINES ATTM.
GFS/UKMET SHOW H85 TEMPS MODERATING A FEW DEGREES WED NGT WITH
PERSISTENT WNW FLOW. IN FACT...THIS WRMG CORRESPONDS TO LOWERING
INVRN HGT UNDER RISING HGTS/DNVA/H85-5 QVECTOR DVGC. THE COMBINATION
OF THESE NEGATIVE DYNAMICS AND INFLUX OF LLVL DRY AIR WL LIKELY
SGNFTLY REDUCE LES AMTS OVER THE NW. AREA OF CONCERN WL BE NR LK SUP
E OF P53...WHERE LONGER FETCH ACRS THE LK AND NOCTURNAL LAND BREEZE
FLOW MAY CONSPIRE TO ENHANCE DOMINANT LES BAND THAT IMPACTS THE
SHORELINE OF ERN ALGER/LUCE COUNTIES. A FUTURE HEADLINE MAY BE
NECESSARY FOR THIS AREA. SHALLOW ARCTIC AIR/HI LLVL STABILITY
WARRANTS FCST LO TEMPS AOB THE LO END OF MOS GUIDANCE.
AS ARCTIC HI PRES CENTER PRESSES INTO THE OH VALLEY AND ANOTHER
SHRTWV APRCHS FM THE W...LLVL FLOW IS FCST TO BACK ON THU. WL SHOW
LES BANDS SHIFTING N TO IMPACT ONLY THE KEWEENAW DURING THE DAY.
OTRW...WL MAINTAIN LO CHC POPS ON THU NGT WITH ARRIVAL OF SHRTWV
DYNAMICS/DEEPER MSTR. CONSIDERING SHALLOW ARCTIC AIR...TENDED BLO
MOS GUIDANCE AGAIN FOR TEMPS.
SOME CHGS IN THE EXTENDED FCST AS PREFERRED 00Z ECMWF SHOWING BLDG
RDG OVER THE SE DOWNSTREAM OF TROFFING OVER THE W AFT PASSAGE OF
LAST CLIPPER SHRTWV ON FRI THRU THE UPR LKS. THE RESULT WL BE MORE
ZONAL FLOW ALF/MODERATION FM THE CHILL THIS WEEK ACRS THE UPR GRT
LKS THIS WEEKEND AS THE COLDEST AIR GETS BOTTLED UP IN CAN CLOSER TO
VORTEX OVER NRN HUDSON BAY. LOOK FOR TEMPS RECOVERING TO AOA NORMAL
BY LATE IN THE WEEKEND. ADDED LO CHC POPS AS NCEP MANUAL GUIDANCE
SHOWS SFC LO STREAKING FM THE PLAINS INTO THE CNTRL GRT LKS OVER THE
WEEKEND. OTRW...EXPECTED HIER TEMPS (ECMWF FCST H85 TEMPS UP TO -5
TO -8C BY 00Z MON) WARRNAT JUST LO CHC POPS FOR LES IN THE WAKE OF
THIS DISTURBANCE.
&&
.AVIATION (FOR THE 00Z TAF ISSUANCE)...
THIS FCST PERIOD AT KCMX/KSAW WILL BE DOMINATED BY LAKE EFFECT -SHSN
UNDER NRLY WINDS. AS IS TYPICAL FOR LAKE EFFECT...VISIBILITIES WILL
FLUCTUATE SIGNIFICANTLY AS BANDS OF -SHSN PASS. WINDS WILL BE LIGHT
(GENERALLY AOB 10KT) THRU THE PERIOD...SO BLSN WILL NOT BE AN ISSUE
TO FURTHER REDUCE VIS. OVERALL...EXPECT VIS TO FLUCTUATE MOSTLY BTWN
MVFR AND IFR THOUGH MVFR WILL MORE FREQUENTLY BE THE RULE. THERE
WILL LIKELY BE SOME PERIODS OF VFR AND POSSIBLY A FEW VERY BRIEF
PERIODS OF LIFR AS WELL. CIGS SHOULD VARY THROUGHOUT THE MVFR RANGE.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
WINDS HAVE DIMINISHED BELOW GALES NOW ON LAKE SUPERIOR THANKS TO THE
CURRENT LOW OVER WESTERN QUEBEC HEADING EASTWARD AND A RIDGE OF HIGH
PRESSURE BUILDING IN FROM NW ONTARIO AND WESTERN WI. HOWEVER...WINDS
ARE GOING TO HAVE A HARD TIME DROPPING MUCH BELOW 20 KNOTS THROUGH
SATURDAY. IN FACT...THERE COULD BE A PERIOD WHERE THE WINDS GET
CLOSE TO GALES WEDNESDAY NIGHT...WHEN HIGH PRESSURE DROPS INTO MN
FROM THE NW TERRITORIES AND TIGHTENTS THE PRESSURE GRADIENT OVER THE
WESTERN GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...ROLFSON
SYNOPSIS/SHORT TERM...AJ
LONG TERM...KC
AVIATION...ROLFSON
MARINE...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
627 PM EST MON DEC 3 2007
UPDATED AVIATION DISCUSSION FOR 00Z TAFS
.SYNOPSIS (ISSUED AT 400 PM EST)...
20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING
OFF THE WEST COAST...RIDGING FROM ALBERTA/SASKATCHEWAN SOUTHWARD
INTO THE DESERT SW...AND TROUGHING OVER THE GREAT LAKES INTO THE
MID-ATLANTIC. BETWEEN THE GREAT LAKES TROUGH AND WESTERN RIDGE...A
140-160KT JET WAS LOCATED NEAR 200MB FROM SASKATCHEWAN THROUGH
SOUTHERN WISCONSIN. THIS JET HAS BEEN TRANSPORTING MOISTURE FROM THE
PACIFIC...NOTED BY MID/HIGH CLOUDS COVERING MUCH OF THE DAKOTAS INTO
MN AND WI...AND NOW THE FAR WESTERN U.P.. WITH THE DOWNSLOPING FLOW
OFF THE ROCKIES...LOW PRESSURE HAS FORMED IN THE WESTERN DAKOTAS.
WARM ADVECTION AHEAD OF THIS LOW IS HELPING TO PRODUCE SOME LIGHT
SNOW OVER MN INTO CENTRAL WI. CLOSER TO HOME...NW FLOW CONTINUES
ACROSS THE GREAT LAKES AROUND LOW PRESSURE IN WESTERN QUEBEC. 850MB
TEMPS OF -12 TO -16C COMBINED WITH SOME MOISTENING OFF LAKE NIPIGON
HAS HELPED TO KEEP LAKE EFFECT SNOW SHOWERS GOING. HOWEVER...THE
INTENSITY HAS DROPPED SINCE THIS MORNING...NOTED BY THE LOSS OF MOST
REFLECTIVITY VALUES ABOVE 24 DBZ. THIS LOSS IS MOSTLY DUE TO THE
LACK OF LAND-BREEZE CONVERGENCE...WHICH USUALLY HAPPENS DURING THE
DAYTIME...IN ADDITION TO LOWERING INVERSIONS (4000 FT ON THE SAW
TAMDAR SOUNDING). WINDS HAVE ALSO BEEN DIMINISHING WITH THE EXIT OF
THE LOW IN WESTERN QUEBEC...WHICH SHOULD BE REDUCING THE BLOWING
SNOW. LAST ITEM TO NOTE IS A SHRTWV TROUGH OVER THE NINAVUT
REGION...WITH 850MB TEMPS AROUND -23C PER 12Z RAOBS.
&&
.SHORT TERM (TONIGHT AND TUESDAY ISSUED AT 400 PM EST)...
UPPER LEVEL PATTERN IS PROGGED TO REMAIN GENERALLY THE SAME THROUGH
TUESDAY...PARTIALLY BECAUSE THE SHRTWV TROUGH OVER THE NINAVUT AREA
IS SHOWN TO DROP SOUTH TOWARDS LAKE SUPERIOR. THUS...VERY LITTLE IF
ANY WARM AIR ADVECTION IS PLANNED DURING THIS PERIOD...MEANING MORE
LAKE EFFECT SNOW. THE ONLY TIME PERIOD WHERE WARM AIR ADVECTION DOES
BECOME SOME FACTOR IS THIS EVENING INTO THE EARLY MORNING HOURS ON
TUESDAY...WHICH IS WHEN THE MID/HIGH CLOUDS WITH SOME LIGHT SNOW ARE
EXPECTED TO MOVE ACROSS. THE MAIN FORECAST CONCERN IS HOW THE LAKE
EFFECT BANDS WILL TRANSITION THEMSELVES. AT THE SURFACE...A HIGH
PRESSURE RIDGE IS EXPECTED TO REMAIN NEARLY STATIONARY FROM THE
NINAVUT REGION INTO NW ONTARIO...AND EVENTUALLY NUDGING DOWN INTO
EASTERN ONTARIO ON TUESDAY AS THE LOW IN QUEBEC MOVES FARTHER AWAY.
MEANWHILE...THE LOW PRESSURE AREA OVER THE DAKOTAS WILL ALSO REMAIN
NEARLY STATIONARY THROUGH TONIGHT...THEN SENT SE ON TUESDAY AS A
SHRTWV MOVES THROUGH THE UPPER FLOW. THE COMBINATION OF THE HIGH AND
LOW PRESSURE AREA TRACKS MEANS THAT THE WINDS SHOULD TURN MORE NORTH
TO NORTHEASTERLY OVER THE NEXT 24 HOURS. 950MB CONVERGENCE FIELDS
FROM THE 12Z NAM AND OUR LOCAL WRF-ARW RUN SUGGESTS THE POSSIBILITY
OF A FAIRLY STRONG BAND (IN PARTICULAR THE WRF-ARW RUN) DEVELOPING
FROM NORTH CENTRAL LAKE SUPERIOR TO AROUND THE SHORELINE OF
ONTONAGON COUNTY AND SW INTO THE SAXON HARBOR AREA. THE ENHANCEMENT
IS A FUNCTION OF BOTH THE LIGHT WARM ADVECTION SNOW MOVING THROUGH
TONIGHT AND LAND-BREEZES CONVERGING ON THE MAIN NE FLOW DOWN WESTERN
LAKE SUPERIOR. HAVE INCREASED POPS AND AMOUNTS NEAR THE SHORE...BUT
STILL KEPT AMOUNTS BELOW ADVISORY AS UNCERTAINTY EXISTS WITH RESPECT
TO BAND PLACEMENT (NAM OFFSHORE AND THE WRF-ARW ONSHORE). EVENING
AND MID-NIGHT SHIFTS WILL NEED TO MONITOR THE LOCATION AND INTENSITY
OF THIS BAND. FARTHER EAST OVER THE NORTH CENTRAL U.P....950MB
CONVERGENCE SUGGESTS MOSTLY MULTI-PARALLEL BANDS WITH OVERALL WEAK
INTENSITY...DUE TO LACK OF ANY SIGNIFICANT LAND-BREEZES AND
INVERSION HEIGHTS REMAINING STUCK BETWEEN 4000-5000 FT. THUS SNOW
ACCUMULATIONS OF 1 TO 3 INCHES PER 12 HOURS SEEMS REASONABLE...WITH
THE GREATEST AMOUNTS OVER THE UPSLOPE AREAS.
REGARDING TEMPS FOR TONIGHT...HAVE BROUGHT THEM UP A COUPLE OF
DEGREES WITH EXPECTED CLOUD COVER MOVING THROUGH...ALONG WITH SOME
SLIGHT WARMING IN THE FLOW OFF SUPERIOR. TEMPS ON TUESDAY SHOULD BE
SIMILAR TO THOSE EXPERIENCED TODAY GIVEN THAT THE AIRMASS IS
SIMILAR.
.LONG TERM (TUESDAY NIGHT THROUGH NEXT MON)...
ON TUE NGT...NAM HAS FINALLY COME ARND TO SCENARIO ADVERTISED BY
GFS/UKMET/CNDN IN SHOWING CLIPPER LO DIGGING SEWD FM IA AT 00Z WED
INTO THE OH VALLEY BY 12Z. TRACK OF THIS SYS SUGS BULK OF SYNOPTIC
SCALE PCPN WL FALL S OF THE FA. BUT WL MAINTAIN CHC POPS...HIEST NR
THE WI BORDER...IN AREA WHERE GFS SHOWS LARGER SCALE H85-5 QVECTOR
CNVGC/ H7 UVV AS WELL AS BAND OF H8-7 FGEN WL IMPACT THE AREA.
OTRW...SUSPECT ARRIVAL OF DEEPER MSTR INTO THE BETTER SN GROWTH LYR
AND RISING INVRN HGT ON CYC SIDE OF SHRTWV/H3 JET SUPPORTING CLIPPER
LO AS SHOWN ON NAM/GFS FCST SDNGS WL TEND TO INTENSIFY ONGOING LES
IN THOSE AREAS FVRD BY NNE FLOW. WL GO WITH LIKELY POPS IN THESE
AREAS. LES CHART SUGS 3-6"/12 HR PSBL FOR EXPECTED INVRN HGT RISING
TO ARND 7K FT AND LK-H85 DELTA-T AOA 20C...BUT SHIFTING WINDS DURING
THE NGT MAY REDUCE TOTAL ACCUMULATION. ANOTHER NEGATIVE INFLUENCE WL
BE THE LARGER SCALE DIFFLUENT NEUTRAL-ACYC LLVL FLOW THAT LIMITS
LLVL CNVGC. EVEN SO...WOULD NOT BE SURPRISED IF A MINIMAL ADVY WL BE
NECESSARY IN THE FVRD LOCATIONS. PREFER THE LOWER GFS MOS GUIDANCE
FOR MIN TEMPS
WL END PCPN SYNOPTIC SCALE PCPN CHCS BY 12Z WED TO ACCOUNT FOR
DEPARTURE OF DYNAMICS ASSOCIATED WITH OH VALLEY CLIPPER AND ARRIVAL
OF MID LVL DRYING/H85-5 QVECTOR DVGC AT THAT TIME. OTRW...NEXT
SHRTWV EMBEDDED WITHIN ARCTIC BRANCH NEAR HUDSON BAY IS FCST TO DIG
SSEWD THRU ONTARIO...CAUSING LLVL FLOW OVER THE CWA TO BACK STEADILY
FM N IN THE MRNG TO WNW IN THE AFTN. AS A RESULT...MOST INTENSE LES
BANDS WL SHIFT TO THE WNW WIND FVRD SN BELTS ACRS THE W AND E OF P53
IN THE AFTN. SHARPENING PRES GRADIENT BTWN ARCTIC HI PRES DIGGING
INTO THE UPR MS VALLEY AND FALLING PRES OVER ONTARIO WL CAUSE WINDS
TO INCRS AS WELL...WITH AREAS OF BLSN DVLPG IN THE SN BELTS MOST
EXPOSED TO THE WNW FLOW. TENDED BLO MOS GUIDANCE FOR TEMPS WITH
INVASION OF RATHER SHALLOW ARCTIC AIR SHOWN ON GFS FCST SDNGS. THIS
VERY DRY LLVL AIR (GFS FCST SDNGS FOR CMX SHOW A MORE PRONOUNCED
INVERTED V) AND SHIFTING WINDS WL TEND TO HOLD LES SN TOTALS DOWN A
BIT...SO DON`T FORSEE THE NEED FOR HEADLINES ATTM.
GFS/UKMET SHOW H85 TEMPS MODERATING A FEW DEGREES WED NGT WITH
PERSISTENT WNW FLOW. IN FACT...THIS WRMG CORRESPONDS TO LOWERING
INVRN HGT UNDER RISING HGTS/DNVA/H85-5 QVECTOR DVGC. THE COMBINATION
OF THESE NEGATIVE DYNAMICS AND INFLUX OF LLVL DRY AIR WL LIKELY
SGNFTLY REDUCE LES AMTS OVER THE NW. AREA OF CONCERN WL BE NR LK SUP
E OF P53...WHERE LONGER FETCH ACRS THE LK AND NOCTURNAL LAND BREEZE
FLOW MAY CONSPIRE TO ENHANCE DOMINANT LES BAND THAT IMPACTS THE
SHORELINE OF ERN ALGER/LUCE COUNTIES. A FUTURE HEADLINE MAY BE
NECESSARY FOR THIS AREA. SHALLOW ARCTIC AIR/HI LLVL STABILITY
WARRANTS FCST LO TEMPS AOB THE LO END OF MOS GUIDANCE.
AS ARCTIC HI PRES CENTER PRESSES INTO THE OH VALLEY AND ANOTHER
SHRTWV APRCHS FM THE W...LLVL FLOW IS FCST TO BACK ON THU. WL SHOW
LES BANDS SHIFTING N TO IMPACT ONLY THE KEWEENAW DURING THE DAY.
OTRW...WL MAINTAIN LO CHC POPS ON THU NGT WITH ARRIVAL OF SHRTWV
DYNAMICS/DEEPER MSTR. CONSIDERING SHALLOW ARCTIC AIR...TENDED BLO
MOS GUIDANCE AGAIN FOR TEMPS.
SOME CHGS IN THE EXTENDED FCST AS PREFERRED 00Z ECMWF SHOWING BLDG
RDG OVER THE SE DOWNSTREAM OF TROFFING OVER THE W AFT PASSAGE OF
LAST CLIPPER SHRTWV ON FRI THRU THE UPR LKS. THE RESULT WL BE MORE
ZONAL FLOW ALF/MODERATION FM THE CHILL THIS WEEK ACRS THE UPR GRT
LKS THIS WEEKEND AS THE COLDEST AIR GETS BOTTLED UP IN CAN CLOSER TO
VORTEX OVER NRN HUDSON BAY. LOOK FOR TEMPS RECOVERING TO AOA NORMAL
BY LATE IN THE WEEKEND. ADDED LO CHC POPS AS NCEP MANUAL GUIDANCE
SHOWS SFC LO STREAKING FM THE PLAINS INTO THE CNTRL GRT LKS OVER THE
WEEKEND. OTRW...EXPECTED HIER TEMPS (ECMWF FCST H85 TEMPS UP TO -5
TO -8C BY 00Z MON) WARRNAT JUST LO CHC POPS FOR LES IN THE WAKE OF
THIS DISTURBANCE.
&&
.AVIATION (FOR THE 00Z TAF ISSUANCE)...
THIS FCST PERIOD AT KCMX/KSAW WILL BE DOMINATED BY LAKE EFFECT -SHSN
UNDER NRLY WINDS. AS IS TYPICAL FOR LAKE EFFECT...VISIBILITIES WILL
FLUCTUATE SIGNIFICANTLY AS BANDS OF -SHSN PASS. WINDS WILL BE LIGHT
(GENERALLY AOB 10KT) THRU THE PERIOD...SO BLSN WILL NOT BE AN ISSUE
TO FURTHER REDUCE VIS. OVERALL...EXPECT VIS TO FLUCTUATE MOSTLY BTWN
MVFR AND IFR THOUGH MVFR WILL MORE FREQUENTLY BE THE RULE. THERE
WILL LIKELY BE SOME PERIODS OF VFR AND POSSIBLY A FEW VERY BRIEF
PERIODS OF LIFR AS WELL. CIGS SHOULD VARY THROUGHOUT THE MVFR RANGE.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
WINDS HAVE DIMINISHED BELOW GALES NOW ON LAKE SUPERIOR THANKS TO THE
CURRENT LOW OVER WESTERN QUEBEC HEADING EASTWARD AND A RIDGE OF HIGH
PRESSURE BUILDING IN FROM NW ONTARIO AND WESTERN WI. HOWEVER...WINDS
ARE GOING TO HAVE A HARD TIME DROPPING MUCH BELOW 20 KNOTS THROUGH
SATURDAY. IN FACT...THERE COULD BE A PERIOD WHERE THE WINDS GET
CLOSE TO GALES WEDNESDAY NIGHT...WHEN HIGH PRESSURE DROPS INTO MN
FROM THE NW TERRITORIES AND TIGHTENTS THE PRESSURE GRADIENT OVER THE
WESTERN GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS/SHORT TERM...AJ
LONG TERM...KC
AVIATION...ROLFSON
MARINE...AJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
400 PM EST MON DEC 3 2007
.SYNOPSIS...20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED TROUGHING OFF THE WEST COAST...RIDGING FROM
ALBERTA/SASKATCHEWAN SOUTHWARD INTO THE DESERT SW...AND TROUGHING
OVER THE GREAT LAKES INTO THE MID-ATLANTIC. BETWEEN THE GREAT LAKES
TROUGH AND WESTERN RIDGE...A 140-160KT JET WAS LOCATED NEAR 200MB
FROM SASKATCHEWAN THROUGH SOUTHERN WISCONSIN. THIS JET HAS BEEN
TRANSPORTING MOISTURE FROM THE PACIFIC...NOTED BY MID/HIGH CLOUDS
COVERING MUCH OF THE DAKOTAS INTO MN AND WI...AND NOW THE FAR
WESTERN U.P.. WITH THE DOWNSLOPING FLOW OFF THE ROCKIES...LOW
PRESSURE HAS FORMED IN THE WESTERN DAKOTAS. WARM ADVECTION AHEAD OF
THIS LOW IS HELPING TO PRODUCE SOME LIGHT SNOW OVER MN INTO CENTRAL
WI. CLOSER TO HOME...NW FLOW CONTINUES ACROSS THE GREAT LAKES AROUND
LOW PRESSURE IN WESTERN QUEBEC. 850MB TEMPS OF -12 TO -16C COMBINED
WITH SOME MOISTENING OFF LAKE NIPIGON HAS HELPED TO KEEP LAKE EFFECT
SNOW SHOWERS GOING. HOWEVER...THE INTENSITY HAS DROPPED SINCE THIS
MORNING...NOTED BY THE LOSS OF MOST REFLECTIVITY VALUES ABOVE 24
DBZ. THIS LOSS IS MOSTLY DUE TO THE LACK OF LAND-BREEZE
CONVERGENCE...WHICH USUALLY HAPPENS DURING THE DAYTIME...IN ADDITION
TO LOWERING INVERSIONS (4000 FT ON THE SAW TAMDAR SOUNDING). WINDS
HAVE ALSO BEEN DIMINISHING WITH THE EXIT OF THE LOW IN WESTERN
QUEBEC...WHICH SHOULD BE REDUCING THE BLOWING SNOW. LAST ITEM TO
NOTE IS A SHRTWV TROUGH OVER THE NINAVUT REGION...WITH 850MB TEMPS
AROUND -23C PER 12Z RAOBS.
&&
.SHORT TERM (TONIGHT AND TUESDAY)...
UPPER LEVEL PATTERN IS PROGGED TO REMAIN GENERALLY THE SAME THROUGH
TUESDAY...PARTIALLY BECAUSE THE SHRTWV TROUGH OVER THE NINAVUT AREA
IS SHOWN TO DROP SOUTH TOWARDS LAKE SUPERIOR. THUS...VERY LITTLE IF
ANY WARM AIR ADVECTION IS PLANNED DURING THIS PERIOD...MEANING MORE
LAKE EFFECT SNOW. THE ONLY TIME PERIOD WHERE WARM AIR ADVECTION DOES
BECOME SOME FACTOR IS THIS EVENING INTO THE EARLY MORNING HOURS ON
TUESDAY...WHICH IS WHEN THE MID/HIGH CLOUDS WITH SOME LIGHT SNOW ARE
EXPECTED TO MOVE ACROSS. THE MAIN FORECAST CONCERN IS HOW THE LAKE
EFFECT BANDS WILL TRANSITION THEMSELVES. AT THE SURFACE...A HIGH
PRESSURE RIDGE IS EXPECTED TO REMAIN NEARLY STATIONARY FROM THE
NINAVUT REGION INTO NW ONTARIO...AND EVENTUALLY NUDGING DOWN INTO
EASTERN ONTARIO ON TUESDAY AS THE LOW IN QUEBEC MOVES FARTHER AWAY.
MEANWHILE...THE LOW PRESSURE AREA OVER THE DAKOTAS WILL ALSO REMAIN
NEARLY STATIONARY THROUGH TONIGHT...THEN SENT SE ON TUESDAY AS A
SHRTWV MOVES THROUGH THE UPPER FLOW. THE COMBINATION OF THE HIGH AND
LOW PRESSURE AREA TRACKS MEANS THAT THE WINDS SHOULD TURN MORE NORTH
TO NORTHEASTERLY OVER THE NEXT 24 HOURS. 950MB CONVERGENCE FIELDS
FROM THE 12Z NAM AND OUR LOCAL WRF-ARW RUN SUGGESTS THE POSSIBILITY
OF A FAIRLY STRONG BAND (IN PARTICULAR THE WRF-ARW RUN) DEVELOPING
FROM NORTH CENTRAL LAKE SUPERIOR TO AROUND THE SHORELINE OF
ONTONAGON COUNTY AND SW INTO THE SAXON HARBOR AREA. THE ENHANCEMENT
IS A FUNCTION OF BOTH THE LIGHT WARM ADVECTION SNOW MOVING THROUGH
TONIGHT AND LAND-BREEZES CONVERGING ON THE MAIN NE FLOW DOWN WESTERN
LAKE SUPERIOR. HAVE INCREASED POPS AND AMOUNTS NEAR THE SHORE...BUT
STILL KEPT AMOUNTS BELOW ADVISORY AS UNCERTAINTY EXISTS WITH RESPECT
TO BAND PLACEMENT (NAM OFFSHORE AND THE WRF-ARW ONSHORE). EVENING
AND MID-NIGHT SHIFTS WILL NEED TO MONITOR THE LOCATION AND INTENSITY
OF THIS BAND. FARTHER EAST OVER THE NORTH CENTRAL U.P....950MB
CONVERGENCE SUGGESTS MOSTLY MULTI-PARALLEL BANDS WITH OVERALL WEAK
INTENSITY...DUE TO LACK OF ANY SIGNIFICANT LAND-BREEZES AND
INVERSION HEIGHTS REMAINING STUCK BETWEEN 4000-5000 FT. THUS SNOW
ACCUMULATIONS OF 1 TO 3 INCHES PER 12 HOURS SEEMS REASONABLE...WITH
THE GREATEST AMOUNTS OVER THE UPSLOPE AREAS.
REGARDING TEMPS FOR TONIGHT...HAVE BROUGHT THEM UP A COUPLE OF
DEGREES WITH EXPECTED CLOUD COVER MOVING THROUGH...ALONG WITH SOME
SLIGHT WARMING IN THE FLOW OFF SUPERIOR. TEMPS ON TUESDAY SHOULD BE
SIMILAR TO THOSE EXPERIENCED TODAY GIVEN THAT THE AIRMASS IS
SIMILAR.
.LONG TERM (TUESDAY NIGHT THROUGH NEXT MON)...
ON TUE NGT...NAM HAS FINALLY COME ARND TO SCENARIO ADVERTISED BY
GFS/UKMET/CNDN IN SHOWING CLIPPER LO DIGGING SEWD FM IA AT 00Z WED
INTO THE OH VALLEY BY 12Z. TRACK OF THIS SYS SUGS BULK OF SYNOPTIC
SCALE PCPN WL FALL S OF THE FA. BUT WL MAINTAIN CHC POPS...HIEST NR
THE WI BORDER...IN AREA WHERE GFS SHOWS LARGER SCALE H85-5 QVECTOR
CNVGC/ H7 UVV AS WELL AS BAND OF H8-7 FGEN WL IMPACT THE AREA.
OTRW...SUSPECT ARRIVAL OF DEEPER MSTR INTO THE BETTER SN GROWTH LYR
AND RISING INVRN HGT ON CYC SIDE OF SHRTWV/H3 JET SUPPORTING CLIPPER
LO AS SHOWN ON NAM/GFS FCST SDNGS WL TEND TO INTENSIFY ONGOING LES
IN THOSE AREAS FVRD BY NNE FLOW. WL GO WITH LIKELY POPS IN THESE
AREAS. LES CHART SUGS 3-6"/12 HR PSBL FOR EXPECTED INVRN HGT RISING
TO ARND 7K FT AND LK-H85 DELTA-T AOA 20C...BUT SHIFTING WINDS DURING
THE NGT MAY REDUCE TOTAL ACCUMULATION. ANOTHER NEGATIVE INFLUENCE WL
BE THE LARGER SCALE DIFFLUENT NEUTRAL-ACYC LLVL FLOW THAT LIMITS
LLVL CNVGC. EVEN SO...WOULD NOT BE SURPRISED IF A MINIMAL ADVY WL BE
NECESSARY IN THE FVRD LOCATIONS. PREFER THE LOWER GFS MOS GUIDANCE
FOR MIN TEMPS
WL END PCPN SYNOPTIC SCALE PCPN CHCS BY 12Z WED TO ACCOUNT FOR
DEPARTURE OF DYNAMICS ASSOCIATED WITH OH VALLEY CLIPPER AND ARRIVAL
OF MID LVL DRYING/H85-5 QVECTOR DVGC AT THAT TIME. OTRW...NEXT
SHRTWV EMBEDDED WITHIN ARCTIC BRANCH NEAR HUDSON BAY IS FCST TO DIG
SSEWD THRU ONTARIO...CAUSING LLVL FLOW OVER THE CWA TO BACK STEADILY
FM N IN THE MRNG TO WNW IN THE AFTN. AS A RESULT...MOST INTENSE LES
BANDS WL SHIFT TO THE WNW WIND FVRD SN BELTS ACRS THE W AND E OF P53
IN THE AFTN. SHARPENING PRES GRADIENT BTWN ARCTIC HI PRES DIGGING
INTO THE UPR MS VALLEY AND FALLING PRES OVER ONTARIO WL CAUSE WINDS
TO INCRS AS WELL...WITH AREAS OF BLSN DVLPG IN THE SN BELTS MOST
EXPOSED TO THE WNW FLOW. TENDED BLO MOS GUIDANCE FOR TEMPS WITH
INVASION OF RATHER SHALLOW ARCTIC AIR SHOWN ON GFS FCST SDNGS. THIS
VERY DRY LLVL AIR (GFS FCST SDNGS FOR CMX SHOW A MORE PRONOUNCED
INVERTED V) AND SHIFTING WINDS WL TEND TO HOLD LES SN TOTALS DOWN A
BIT...SO DON`T FORSEE THE NEED FOR HEADLINES ATTM.
GFS/UKMET SHOW H85 TEMPS MODERATING A FEW DEGREES WED NGT WITH
PERSISTENT WNW FLOW. IN FACT...THIS WRMG CORRESPONDS TO LOWERING
INVRN HGT UNDER RISING HGTS/DNVA/H85-5 QVECTOR DVGC. THE COMBINATION
OF THESE NEGATIVE DYNAMICS AND INFLUX OF LLVL DRY AIR WL LIKELY
SGNFTLY REDUCE LES AMTS OVER THE NW. AREA OF CONCERN WL BE NR LK SUP
E OF P53...WHERE LONGER FETCH ACRS THE LK AND NOCTURNAL LAND BREEZE
FLOW MAY CONSPIRE TO ENHANCE DOMINANT LES BAND THAT IMPACTS THE
SHORELINE OF ERN ALGER/LUCE COUNTIES. A FUTURE HEADLINE MAY BE
NECESSARY FOR THIS AREA. SHALLOW ARCTIC AIR/HI LLVL STABILITY
WARRANTS FCST LO TEMPS AOB THE LO END OF MOS GUIDANCE.
AS ARCTIC HI PRES CENTER PRESSES INTO THE OH VALLEY AND ANOTHER
SHRTWV APRCHS FM THE W...LLVL FLOW IS FCST TO BACK ON THU. WL SHOW
LES BANDS SHIFTING N TO IMPACT ONLY THE KEWEENAW DURING THE DAY.
OTRW...WL MAINTAIN LO CHC POPS ON THU NGT WITH ARRIVAL OF SHRTWV
DYNAMICS/DEEPER MSTR. CONSIDERING SHALLOW ARCTIC AIR...TENDED BLO
MOS GUIDANCE AGAIN FOR TEMPS.
SOME CHGS IN THE EXTENDED FCST AS PREFERRED 00Z ECMWF SHOWING BLDG
RDG OVER THE SE DOWNSTREAM OF TROFFING OVER THE W AFT PASSAGE OF
LAST CLIPPER SHRTWV ON FRI THRU THE UPR LKS. THE RESULT WL BE MORE
ZONAL FLOW ALF/MODERATION FM THE CHILL THIS WEEK ACRS THE UPR GRT
LKS THIS WEEKEND AS THE COLDEST AIR GETS BOTTLED UP IN CAN CLOSER TO
VORTEX OVER NRN HUDSON BAY. LOOK FOR TEMPS RECOVERING TO AOA NORMAL
BY LATE IN THE WEEKEND. ADDED LO CHC POPS AS NCEP MANUAL GUIDANCE
SHOWS SFC LO STREAKING FM THE PLAINS INTO THE CNTRL GRT LKS OVER THE
WEEKEND. OTRW...EXPECTED HIER TEMPS (ECMWF FCST H85 TEMPS UP TO -5
TO -8C BY 00Z MON) WARRNAT JUST LO CHC POPS FOR LES IN THE WAKE OF
THIS DISTURBANCE.
&&
.AVIATION (FOR THE 18Z TAF ISSUANCE)...
MUCH OF THIS FORECAST IS DOMINATED BY LAKE EFFECT SNOW FOR BOTH TAF
SITES...THOUGH THERE IS AN AREA OF FLURRIES/-SN MOVING ACROSS MN
TOWARDS UPPER MI ASSOCIATED WITH A SYSTEM OVER THE DAKOTAS. CURRENT
NW WINDS CONTINUE TO FAVOR CMX FOR RECEIVING MUCH OF THE LAKE
EFFECT...THOUGH EVEN HERE THE VISIBILITIES SHOULD IMPROVED DUE TO A
COMBINATION OF DIMINISHING WINDS AND THE BANDS THEMSELVES WEAKENING.
VFR CONDITIONS OVERALL EXPECTED AT SAW...POSSIBLY MVFR AT THE START
AS RADAR SHOWS SOME LAKE EFFECT BANDS WITHIN THE VICINITY. AFTER
00Z...SOME OF THE MOISTURE AND -SN OBSERVED OVER NORTHERN MN WILL
MOVE OVER THE TAF SITES. IN ADDITION...THE WINDS ARE PROGGED TO TURN
MORE NORTHERLY OR EVEN NORTHEASTERLY...WHICH GENERALLY FAVORS SAW TO
GET THE HEAVIER LAKE EFFECT. HOWEVER...THERE IS A POSSIBILITY OF A
LAKE EFFECT BAND THAT COULD AFFECT CMX BETWEEN 02-05Z...AND
HIGHLIGHTED THAT WITH A TEMPO OF IFR VISIBILITY. AT SAW...ONLY
BROUGHT VISIBILITIES TO MVFR...BUT WOULD NOT BE SURPRISED IF THEY
DROPPED LOWER...PARTICULARLY IF THE INCOMING -SN IS HEAVIER THEN
FORECAST. MUCH OF THE -SN OVER MN SHOULD MOVE OUT BY 06Z...LEAVING
ONLY LAKE EFFECT TO WORRY ABOUT. WITH WINDS MORE NORTHEAST AT
CMX...HAVE LEFT THE IDEA OF VFR VISIBILITY BUT STILL MAINTAINED AN
MVFR CEILING. SAW WILL BE STUCK UNDER N TO NE FLOW...WHICH FAVORS AT
LEAST HOLDING ON TO MVFR VSBYS AND CEILINGS THROUGH THE PERIOD.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
WINDS HAVE DIMINISHED BELOW GALES NOW ON LAKE SUPERIOR THANKS TO THE
CURRENT LOW OVER WESTERN QUEBEC HEADING EASTWARD AND A RIDGE OF HIGH
PRESSURE BUILDING IN FROM NW ONTARIO AND WESTERN WI. HOWEVER...WINDS
ARE GOING TO HAVE A HARD TIME DROPPING MUCH BELOW 20 KNOTS THROUGH
SATURDAY. IN FACT...THERE COULD BE A PERIOD WHERE THE WINDS GET
CLOSE TO GALES WEDNESDAY NIGHT...WHEN HIGH PRESSURE DROPS INTO MN
FROM THE NW TERRITORIES AND TIGHTENTS THE PRESSURE GRADIENT OVER THE
WESTERN GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW AND BLSN ADVY UNTIL 6PM EST MIZ006-085.
&&
$$
SYNOPSIS/SHORT TERM...AJ
LONG TERM...KC
AVIATION...AJ
MARINE...AJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
932 PM CST SAT DEC 1 2007
.UPDATE...
MAIN FORCING LIFTING FAIRLY RAPIDLY OFF TO THE NE. SOMEWHAT OF A
CIRCULATION INDICATED ON RADAR LOOP LOCATED SE OF MSP AND ANOTHER
OVER NORTH CENTRAL SD. COLDER ICE BEARING CLOUDS MAINLY UP OVER N
MN ATTM...BUT DO EXTEND INTO CENTRAL MN. MORE SIG SNOW STILL OVER
PARTS OF EAST CENTRAL MN INTO WEST CENTRAL WI WHERE NORTH EDGE OF
LAYER THETA E ADVECTION AND BEST MID LEVEL TEMP GRADIENT
COINCIDED. THIS PATTER DOES LIFT NE AFTER MIDNIGHT...BUT THREAT
OF FREEZING DRIZZLE REMAINS WITH MID CLOUDS CLEARING. HAVE HOWEVER...
CLEARED PART OF SW OUT OF WARNING AS COLDER COLUMN MOVES IN...AND
GENERALLY IN SINKING BEHIND WAVE. MAY CLEAR OUT OTHER AREAS BEFORE
MIDNIGHT...IF IMPROVING TREND CONTINUES.
.AVIATION.../00Z TAF ISSUANCE/
TRICKY AVIATION NIGHT WITH FREEZING RAIN AND SLEET BOTH BEING
THREATS. OBS OF BOTH HAVE PLOWED NORTHWARD IN SRN MN AND WRN WI
SINCE 2230Z...AND THIS CORRELATES WELL WITH WARMER CLOUD TOP TEMPS
UNSUPPORTIVE OF SNOW PRODUCTION. THERMAL PROFILES FROM TAMDAR
SOUNDINGS AND DIAGNOSTIC MODELS INDICATING A VERY DEEP WARM LAYER
/-1 TO -4C/ OF 6 TO 9 KFT IN THIS AREA. COLD SURFACE LAYER APPEARS
DEEP ENOUGH FOR SLEET BY CONVENTIONAL RULES...HOWEVER THE WARM
LAYER ALOFT APPEARS TO BE WINNING OUT AND AN INITIAL SURFACE PRE-
WARM FRONT HAS PUSHED INTO SRN MN HELPING ALSO TO ENFORCE LOWER
LEVEL WARM AIR ADVECTION. SO FOR MSP...RNH...AND EAU HAVE GONE
WITH A PRIMARY FREEZING PRECIP...INCLUDING ICE PELLETS...FOR MUCH
OF THE EVE. DEFORMATION AREA CURRENT LEADING TO BANDING SNOW NEAR
AXN TOWARDS STC. EVEN A LIGHTNING STRIKE SEEN NEAR STC AIRPORT
SINCE 23Z. THROUGH THE NEXT COUPLE HOURS THAT IMPLIES CONTINUED
SNOW...WITH SOME VLIFR VISBYS LIKELY. ALL SITES SHOULD SEE A
REDUCTION IN MODERATE TO HEAVY PRECIP BY LATE EVE AS SYNOPTIC
FORCING SHIFTS NORTHEAST. HOWEVER...VISBYS SHOULD REMAIN LOW WITH
A COMBO OF BLOWING SNOW...FREEZING DRIZZLE...AND LOW LEVEL
SATURATION REMAINING IN PLACE. THIS WILL ALSO HELP CIGS TO STAY
LOW...THOUGH MORE IMPROVEMENT IS EXPECTED THAN WITH VISBYS.
TOMORROW...IN THE BACKSIDE CYCLONIC FLOW...THE LOW LEVEL MOISTURE
WILL BE SLOW TO DEPART AND SOME SNOW SHOWERS LOOK LIKE A GOOD
POSSIBILITY IN CTRL MN AND WRN WI.
&&
.PREV DISCUSSION...
/ISSUED 354 PM CST SAT DEC 1 2007/
STRONG WAA CONTINUES OVER THE EASTERN TWO-THIRDS OF THE CWA ATTM
PER RUC/SREF PROGS. BEST SNOWFALL RUNS FROM WEST CENTRAL MN
THROUGH CENTRAL MN TO WEST CENTRAL WI IN DEFORMATION ZONE. AXIS
WILL BE SHIFTING NORTHEAST THIS EVENING AS DRY AIR BEGINS TO PLOW
IN FROM THE SOUTHWEST. STILL CONCERNED ABOUT WEST CENTRAL MN
THROUGH THE EVENING AS THE SHORT WAVE OVER SD/NE MOVES NORTHEAST
ACROSS THE AREA. STRONG LAYER FWF IS DEPICTED ALONG WITH
INSTABILITY ABOVE. SO A FEW MORE INCHES OF SNOW PROGGED. SLEET HAS
DOMINATED OVER FAR SOUTHERN MN THROUGH MUCH OF THE DAY WITH SOME
REPORT OF DEPTHS REACHING 4 INCHES. FREEZING RAIN IS NOW STARTED
TO BE REPORTED HERE AND THERE ACROSS THE FAR SOUTH AS THE NOSE OF
THE WARM LAYER ABOVE 0 DEG C IS LOWERING PER LAPS/RUC PROFILES.
DECISION WAS TO LEAVE THE WARNING IN PLACE WITH VARIOUS PRECIP
TYPES OCCURRING ALONG WITH 20 TO 25 MPH SUSTAINED WINDS. CHANGES
WILL LIKELY BE MADE DURING THE EVENING. SMALL AREA OF DRYING ALOFT
EVIDENT FROM THE TWIN CITIES ON SOUTHWEST TO FAIRMONT WHICH WILL
DIMINISH PRECIPITATION INTENSITY. MORE SUBSTANTIAL DRYING ALOFT
STILL EXPECTED LATER TONIGHT WITH SATURATED LOW LEVEL PROFILES AND
TEMPERATURES RUNNING IN THE SINGLE DIGITS BELOW ZERO. FREEZING
DRIZZLE STILL LOOKING GOOD. SOME SNOW SHOWERS ON SUNDAY AS ANOTHER
SHORT WAVE MOVES ACROSS THE REGION. THE WEEK AHEAD FEATURES A
STRONG CLIPPER MOVING SOUTHEAST ACROSS THE REGION TUESDAY AND
TUESDAY NIGHT. GOOD CONTINUITY FROM DAY TO DAY ON THIS SYSTEM.
RAISED POPS SOME MORE. WITH THE STORM TODAY TAKING A LOT OF OUR
TIME...LATER SHIFTS MAY WANT TO BOOST POPS INTO THE LIKELY
CATEGORY. YET ANOTHER SNOW EVENT SHAPING UP FOR NEXT WEEKEND PER
THE ECMWF WHICH AGREED MORE WITH HPC THINKING OVER THAT OF THE
GFS. THE EVENT NEXT WEEKEND IS ONE FROM THE SOUTHWESTERN U.S. SOME
COLD NIGHTS IN BETWEEN THE VARIOUS SNOW EVENTS DURING THE NEXT
SEVEN DAYS WITH SNOW NOW COVERING THE GROUND. NIGHTS WHERE SKIES
ARE CLEAR TO PARTLY CLOUDY WILL LIKELY FEATURE LOWS IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR ANOKA-BENTON-
CARVER-CHISAGO-DAKOTA-DOUGLAS-GOODHUE-HENNEPIN-ISANTI-
KANABEC-KANDIYOHI-LE SUEUR-MCLEOD-MEEKER-MILLE LACS-
MORRISON-POPE-RAMSEY-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-
STEELE-STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WRIGHT.
WI...WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR BARRON-CHIPPEWA-
DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
RAH/MTF/JPR
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
616 PM CST SAT DEC 1 2007
.DISCUSSION...
STRONG WAA CONTINUES OVER THE EASTERN TWO-THIRDS OF THE CWA ATTM
PER RUC/SREF PROGS. BEST SNOWFALL RUNS FROM WEST CENTRAL MN
THROUGH CENTRAL MN TO WEST CENTRAL WI IN DEFORMATION ZONE. AXIS
WILL BE SHIFTING NORTHEAST THIS EVENING AS DRY AIR BEGINS TO PLOW
IN FROM THE SOUTHWEST. STILL CONCERNED ABOUT WEST CENTRAL MN
THROUGH THE EVENING AS THE SHORT WAVE OVER SD/NE MOVES NORTHEAST
ACROSS THE AREA. STRONG LAYER FWF IS DEPICTED ALONG WITH
INSTABILITY ABOVE. SO A FEW MORE INCHES OF SNOW PROGGED. SLEET HAS
DOMINATED OVER FAR SOUTHERN MN THROUGH MUCH OF THE DAY WITH SOME
REPORT OF DEPTHS REACHING 4 INCHES. FREEZING RAIN IS NOW STARTED
TO BE REPORTED HERE AND THERE ACROSS THE FAR SOUTH AS THE NOSE OF
THE WARM LAYER ABOVE 0 DEG C IS LOWERING PER LAPS/RUC PROFILES.
DECISION WAS TO LEAVE THE WARNING IN PLACE WITH VARIOUS PRECIP
TYPES OCCURRING ALONG WITH 20 TO 25 MPH SUSTAINED WINDS. CHANGES
WILL LIKELY BE MADE DURING THE EVENING. SMALL AREA OF DRYING
ALOFT EVIDENT FROM THE TWIN CITIES ON SOUTHWEST TO FAIRMONT WHICH
WILL DIMINISH PRECIPITATION INTENSITY. MORE SUBSTANTIAL DRYING
ALOFT STILL EXPECTED LATER TONIGHT WITH SATURATED LOW LEVEL
PROFILES AND TEMPERATURES RUNNING IN THE SINGLE DIGITS BELOW ZERO.
FREEZING DRIZZLE STILL LOOKING GOOD. SOME SNOW SHOWERS ON SUNDAY
AS ANOTHER SHORT WAVE MOVES ACROSS THE REGION. THE WEEK AHEAD
FEATURES A STRONG CLIPPER MOVING SOUTHEAST ACROSS THE REGION
TUESDAY AND TUESDAY NIGHT. GOOD CONTINUITY FROM DAY TO DAY ON THIS
SYSTEM. RAISED POPS SOME MORE. WITH THE STORM TODAY TAKING A LOT
OF OUR TIME...LATER SHIFTS MAY WANT TO BOOST POPS INTO THE LIKELY
CATEGORY. YET ANOTHER SNOW EVENT SHAPING UP FOR NEXT WEEKEND PER
THE ECMWF WHICH AGREED MORE WITH HPC THINKING OVER THAT OF THE GFS.
THE EVENT NEXT WEEKEND IS ONE FROM THE SOUTHWESTERN U.S. SOME
COLD NIGHTS IN BETWEEN THE VARIOUS SNOW EVENTS DURING THE NEXT
SEVEN DAYS WITH SNOW NOW COVERING THE GROUND. NIGHTS WHERE SKIES
ARE CLEAR TO PARTLY CLOUDY WILL LIKELY FEATURE LOWS IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO.
&&
.AVIATION.../00Z TAF ISSUANCE/
TRICKY AVIATION NIGHT WITH FREEZING RAIN AND SLEET BOTH BEING
THREATS. OBS OF BOTH HAVE PLOWED NORTHWARD IN SRN MN AND WRN WI
SINCE 2230Z...AND THIS CORRELATES WELL WITH WARMER CLOUD TOP TEMPS
UNSUPPORTIVE OF SNOW PRODUCTION. THERMAL PROFILES FROM TAMDAR
SOUNDINGS AND DIAGNOSTIC MODELS INDICATING A VERY DEEP WARM LAYER
/-1 TO -4C/ OF 6 TO 9 KFT IN THIS AREA. COLD SURFACE LAYER APPEARS
DEEP ENOUGH FOR SLEET BY CONVENTIONAL RULES...HOWEVER THE WARM
LAYER ALOFT APPEARS TO BE WINNING OUT AND AN INITIAL SURFACE PRE-
WARM FRONT HAS PUSHED INTO SRN MN HELPING ALSO TO ENFORCE LOWER
LEVEL WARM AIR ADVECTION. SO FOR MSP...RNH...AND EAU HAVE GONE
WITH A PRIMARY FREEZING PRECIP...INCLUDING ICE PELLETS...FOR MUCH
OF THE EVE. DEFORMATION AREA CURRENT LEADING TO BANDING SNOW NEAR
AXN TOWARDS STC. EVEN A LIGHTNING STRIKE SEEN NEAR STC AIRPORT
SINCE 23Z. THROUGH THE NEXT COUPLE HOURS THAT IMPLIES CONTINUED
SNOW...WITH SOME VLIFR VISBYS LIKELY. ALL SITES SHOULD SEE A
REDUCTION IN MODERATE TO HEAVY PRECIP BY LATE EVE AS SYNOPTIC
FORCING SHIFTS NORTHEAST. HOWEVER...VISBYS SHOULD REMAIN LOW WITH
A COMBO OF BLOWING SNOW...FREEZING DRIZZLE...AND LOW LEVEL
SATURATION REMAINING IN PLACE. THIS WILL ALSO HELP CIGS TO STAY
LOW...THOUGH MORE IMPROVEMENT IS EXPECTED THAN WITH VISBYS.
TOMORROW...IN THE BACKSIDE CYCLONIC FLOW...THE LOW LEVEL MOISTURE
WILL BE SLOW TO DEPART AND SOME SNOW SHOWERS LOOK LIKE A GOOD
POSSIBILITY IN CTRL MN AND WRN WI.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS-
FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE
LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-
SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-
WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR BARRON-CHIPPEWA-
DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.
&&
$$
RAH/MTF
AREA FORECAST DISCUSSION...DELAYED
NWS SEATTLE WA
451 PM PST MON DEC 3 2007
.SYNOPSIS...MOIST...WESTERLY FLOW ALOFT IN THE WAKE OF THE POWERFUL
STORM SYSTEM THAT MOVED THROUGH EARLIER WILL KEEP CONDITIONS
UNSETTLED THROUGH TUESDAY FOR SHOWERY WEATHER. EXPECT A SLOW DRYING
TREND TUESDAY NIGHT THROUGH FRIDAY AS DRY...NORTHERLY FLOW SETS UP
OVER THE REGION. THERE WILL ALSO BE A COOLING TREND THIS WEEK...WITH
TEMPERATURES FALLING BELOW NORMAL AGAIN BY THE END OF THE WEEK.
&&
.SHORT TERM...
INCLEMENT WEATHER WAS KEEPING US VERY BUSY TODAY. THE CDFNT HAS
MOVED ACROSS MUCH OF THE AREA AND WAS OVER THE CASCADES AT THIS
TIME. THE HIGH WINDS ON THE COAST AND OVER THE MOUNTAINS WILL
SUBSIDE THIS EVENING WITH BREEZY OR WINDY CONDITIONS PREVAILING
OVERNIGHT.
MEANWHILE...THE STEADY...HEAVY RAIN HAS ENDED WITH SHOWERS OCCURRING
OVER THE AREA AT THIS TIME. RAINFALL AMOUNTS HAVE BEEN IMPRESSIVE
AND HAVE LED TO FAIRLY WIDESPREAD FLOODING. TO COMPLICATE MATTERS...
THE RAIN FELL ON TOP OF MELTING SNOW IN THE MOUNTAINS THAT
CONTRIBUTED TO MAJOR FLOODING OF SOME RIVERS TODAY. SOME STORM TOTAL
RAINFALL AMOUNTS...8-12 INCHES IN THE OLYMPICS...10.78 INCHES IN
BREMERTON...THE SEATTLE/TACOMA AREA BETWEEN 2.5 AND 5 INCHES...AND
1.5 TO 3 INCHES IN THE CASCADES.
EXPECT SHOWERS TO PERSIST OVERNIGHT THROUGH TUE. THE NEARLY
ZONAL...MOIST FLOW ALOFT WILL CONTAIN EMBEDDED...DIFFICULT TO TIME
AND PINPOINT...IMPULSES THAT WILL KEEP THE WEATHER PATTERN
UNSETTLED. SLOWLY IMPROVING WEATHER WILL OCCUR TUE NIGHT THRU WED AS
DRIER...NLY FLOW ALOFT BECOMES ESTABLISHED OVER THE REGION. HAVE CUT
BACK ON THE POPS FOR THE WED NIGHT THRU FRI TIME FRAME IN
EXPECTATION OF AN UPPER RIDGE OFFSHORE GIVING THE AREA DRY WEATHER.
HOWEVER THIS SITUATION BEARS WATCHING AS AN UPPER TROF COMING DOWN
FROM THE N COMBINED WITH COLD AIR ADVECTION COULD BRING SOME SNOW TO
THE LOWLANDS AGAIN DURING THIS PERIOD. 05
.LONG TERM...GLOBAL MODELS ARE GENERALLY SHOWING REDEVELOPMENT OF
LONG WAVE RIDGING AROUND 140-145W WITH DEEP TROUGHING IN THE DESERT
SW DURING THE FRIDAY THROUGH MONDAY PERIOD. NWLY FLOW ALOFT AND
HIGHER SURFACE PRESSURES OVER BRITISH COLUMBIA WOULD GIVE
TEMPERATURES A FEW DEGREES BELOW NORMAL FOR THIS PERIOD. TIMING OF
INDIVIDUAL FEATURES IS PROBLEMATIC AS MODELS SHOW TIMING
INCONSISTENCIES. SOME SOLUTIONS SHOW SYSTEMS SLIDING ESE ALONG OR
JUST OFF THE COAST...PARTICULARLY SUN THEN AGAIN MON. OTHER
SOLUTIONS ARE A BIT FARTHER EAST WITH THE TRACK OF THE SYSTEMS.
TEMPERATURES IN THE LOWER LEVELS WITH SYSTEMS SLIDING BY TO THE WEST
WOULD RESULT IN PRECIPITATION BEING IN THE FORM OF SNOW AT
TIMES...PARTICULARLY NORTH OF SEATTLE AND DURING THE NIGHT HOURS.
FOR NOW WILL KEEP FRI AND FRI NIGHT DRY THEN BRING CHANCE POPS INTO
THE LOWLANDS WITH LIKELY POPS IN THE MOUNTAINS DURING THE REMAINDER
OF THE PERIOD. ALBRECHT
&&
.AVIATION...A STRONG PACIFIC STORM SYSTEM LOCATED OFFSHORE WILL
CONTINUE TO TRACK NORTHEAST THIS EVENING TOWARD SOUTHWESTERN
BC...RIGHT BETWEEN VANCOUVER ISLAND AND THE QUEEN CHARLOTTES. RADAR
TRENDS SHOW PRECIP COVERAGE AND INTENSITY DECREASING...BUT STILL
EXPECTING SCATTERED SHOWERS ACROSS THE AREA THROUGH THE OVERNIGHT
HOURS. ALOFT...ACARS SOUNDINGS SHOW STRONG SW WINDS WITH 50 TO 70KTS
FROM 5K TO 10K FT. IN GENERAL...WINDS WILL DECREASE IN INTENSITY
LATER THIS EVENING AS THIS SYSTEM TRACKS FURTHER NE TOWARD BC.
.KSEA...EXPECT SCATTERED SHOWERS TO CONTINUE THROUGH THE EVENING AND
INTO THE OVERNIGHT HOURS...BUT OVERALL INTENSITY SHOULD BE
DECREASING. TEMPS ALOFT ARE FAIRLY WARM AND NOT EXPECTING ANY
THUNDER. STRONG WINDS AT THE SURFACE WILL CONTINUE THROUGH AT LEAST
04Z AT 20 TO 30KTS. 33
&&
.MARINE...A VERY STRONG 975 MB SURFACE LOW LOCATED NEAR 47N AND 135W
WILL TRACK NE THIS EVENING TOWARD SW BC RIGHT BETWEEN VANCOUVER
ISLAND AND THE QUEEN CHARLOTTES. THIS SYSTEM WILL CONTINUE TO
PRODUCE GALE FORCE WINDS...ESPECIALLY OVER THE COASTAL WATERS AND
WEST ENTRANCE OF THE STRAIT OF JUAN DE FUCA. FOR THE INLAND
WATERS...WILL CONTINUE WITH GALES BUT EXPECT WINDS WILL WEAKEN DOWN
TO SMALL CRAFT ADVISORY CRITERIA LATER THIS EVENING. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
1. FLOOD WARNINGS...ADVISORIES...AND/OR WATCHES ARE IN EFFECT FOR
WRN WA
2. A HIGH WIND WARNING IS IN EFFECT FOR THE NORTH/CENTRAL
COAST...OLYMPICS...AND WESTERN STRAIT TIL 7 PM TONIGHT
3. A COASTAL FLOOD WARNING IS IN EFFECT FOR THE CENTRAL COAST TIL
4 AM TUE
4. HIGH SURF WARNING IS IN EFFECT FOR THE NORTH COAST UNTIL 4 AM
TUE
5. A WIND ADVISORY IS IN EFFECT FOR THE INTERIOR LOWLANDS UNTIL 7 PM
TONIGHT
6. A COASTAL FLOOD WATCH IS IN EFFECT FOR THE NORTH COAST UNTIL 4 AM
TUE
7. GALE WARNINGS ARE IN EFFECT FOR ALL WATERS
$$
WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION...DELAYED
NWS SEATTLE WA
348 PM PST MON DEC 3 2007
PRODUCT IS DELAYED DUE TO INCLEMENT WEATHER. ESTIMATED TIME OF
ISSUANCE 430 PM PST.
.SYNOPSIS...A POWERFUL STORM SYSTEM HEADING NORTHEAST TOWARD BRITISH
COLUMBIA WILL BRING HEAVY RAINS TO THE AREA ALONG WITH DAMAGING
WINDS TO THE COAST TODAY. THE STEADY RAIN WILL TAPER OFF TO SHOWERS
TONIGHT ONCE THE COLD FRONT MOVES THROUGH. MOIST...ONSHORE FLOW WILL
KEEP THE WEATHER UNSETTLED ON TUESDAY.
&&
.SHORT TERM...
VERY BUSY THIS MORNING WITH FLOODING AND HIGH WINDS. HIGH WINDS
CONTINUED OVER THE COAST AND OLYMPICS THIS MORNING...WITH WINDS
GUSTING AS HIGH AS 93 MPH AT SEKIU EARLIER TODAY. ELSEWHERE WINDS
WERE MUCH LIGHTER...THUS HAD DOWNGRADED THE HIGH WIND WARNING ISSUED
EARLIER FOR THE HOOD CANAL AREA...ADMIRALTY INLET...ERN STRAIT OF
JUAN DE FUCA...AND EVERETT AND VICINITY. FOR THE MOST PART...THE
STRONGEST WINDS WILL BE OVER THE COAST AND OLYMPICS TODAY.
CONCERNING FLOODING...URBAN/SMALL STREAM FLOOD WARNINGS ARE POSTED
FOR THE ENTIRE AREA DUE TO THE HEAVY RAINS. 10-15 OLYMPICS AND SW
PART OF THE CWA WITH LESSER...BUT STILL SIGNIFICANT...AMOUNTS
ELSEWHERE. RAIN...HEAVY AT TIMES...WILL PERSIST BEFORE GRADUALLY
DECREASING LATER TODAY.
.LONG TERM...FROM THE PREV DISCUSSION...GFS SHOWS AN UPPER LEVEL
RIDGE BUILDING W OF B.C. WEDNESDAY...AND SHOWS IT STRONG ENOUGH BY
THURSDAY FOR DRY NW FLOW TO DEVELOP OVER W WA. MAY BE BE POSSIBLE TO
DROP THE SHOWERS AND GO WITH A DRY FORECAST AT LEAST FRIDAY AND
SATURDAY. WILL LEAVE THAT FOR THE DAY SHIFT. KAM
&&
.HYDRO...FROM THE PREV DISCUSSION...HUGE PRECIPITATION AMOUNTS
EXPECTED IN THE MOUNTAINS THROUGH TUESDAY MORNING. ACARS SOUNDINGS
SHOW THE FREEZING LEVEL OVER KSEA HAS GONE UP RAPIDLY IN THE LAST
COUPLE OF HOURS TO NEAR 9000 FEET. SOUTHWEST WINDS IN THE 850-700MB
LAYER RANGE FROM 80-100 KNOTS. THESE WINDS ARE NOT FORECAST TO
DIMINISH UNTIL AFTER 21Z. HEAVIEST PRECIPITATION IN THE NEXT 12
HOURS BUT MOIST WARM SOUTHWESTERLY FLOW ALOFT CONTINUING THROUGH
TUESDAY KEEPING THE PRECIPITATION GOING ESPECIALLY IN THE MOUNTAINS.
WYNOOCHEE DAM HAS RECEIVED 2.50 INCHES OF RAIN BETWEEN 06Z-10Z.
UPDATED QPF FOR OVER 6 INCHES OF RAIN IN THE OLYMPICS FOR THE 30
HOURS AND ANYWHERE FROM 4 TO 6 INCHES IN THE CASCADES. WITH THIS
AMOUNT OF PRECIPITATION ALL MAJOR STEM RIVERS IN WESTERN WASHINGTON
HAVE THE POTENTIAL TO FLOOD WITH MAJOR FLOODING POSSIBLE ON RIVERS
FLOWING OFF THE OLYMPICS. HEAVY PRECIPITATION IN THE LOWLANDS
THROUGH THIS AFTERNOON AS WELL. WILL ADD AN URBAN AND SMALL STREAM
FLOOD WARNING TO THE MIX AS WELL THIS MORNING. FELTON
&&
.AVALANCHE...FROM THE PREV DISCUSSION...EXISTING UNSTABLE SNOWPACK
STRUCTURE AND INCREASING LOADS DUE TO STRONG WINDS...VERY HEAVY SNOW
THEN RAIN...AND WARMING TREND FULLY EXPECTED TO CAUSE THE AVALANCHE
CYCLE TO CONTINUE TODAY. BACK COUNTRY TRAVEL IN AVALANCHE TERRAIN
NOT RECOMMENDED TODAY. PLEASE SEE WWW.NWAC.US FOR DETAILS. FERBER
&&
.AVIATION...A STRONG PACIFIC SYSTEM LOCATED OFFSHORE WILL CONTINUE
TO TRACK NORTHEAST TODAY WITH MODERATE RAINFALL CONTINUING ACROSS
WESTERN WASHINGTON. STRONG SOUTHERLY FLOW AT THE SURFACE WILL
PRODUCE SOME HEAVY SHOWERS ACROSS THE AREA WHICH WILL KNOCK
VISIBILITY AND CEILINGS DOWN TO IFR CONDITIONS. ALOFT...ACARS
SOUNDINGS SHOW STRONG SW WINDS WITH 50-60KTS AT 5K FT AND 10K FT
THIS MORNING...ALTHOUGH MODEL SOUNDINGS SHOW SW WINDS INCREASING TO
NEAR 100KTS AT 5K THIS AFTERNOON AS 150KT JET SLIDES OVER THE AREA.
IN GENERAL...WINDS AND RAIN WILL DECREASE IN INTENSITY LATER THIS
EVENING AS THIS SYSTEM TRACKS FURTHER N INTO BC.
.KSEA...EXPECT MODERATE TO HEAVY SHOWERS TO CONTINUE THROUGH THE
AFTERNOON AND EVENING. STRONG SHOWERS MAY LOWER THE VIS AND CIGS
DOWN TO IFR CONDITIONS. TEMPS ALOFT ARE FAIRLY WARM AND NOT
EXPECTING ANY THUNDER. WINDS AT THE SURFACE WILL PICK UP TO 15 TO
25KTS THIS AFTERNOON...WITH STRONGER WINDS ALOFT TO NEAR 100KT UP AT
5K FT AS JET STREAK MOVES OVER THE AREA. 33
&&
.MARINE...A VERY STRONG 965 MB SURFACE LOW LOCATED NEAR 45N AND 140W
WILL TRACK NE THIS AFTERNOON AND EVENING TOWARD THE QUEEN CHARLOTTE
ISLANDS. THIS SYSTEM PRODUCED VERY STRONG WINDS EARLIER IN THE
MORNING UP TO HURRICANE FORCE...HOWEVER THE WINDS...ALBEIT STILL
STRONG...HAVE DECREASED DOWN TO STORM FORCE. COMBINED SEAS SHOW 30
TO 35 FEET. ACROSS...THE INLAND WATERS...EXPECTING GALE FORCE WINDS
TO DEVELOP THIS AFTERNOON AS THIS SYSTEM TRACKS CLOSER TO THE AREA.
WINDS ARE EXPECTED TO DECREASE LATER THIS EVENING BUT WILL MAINTAIN
AT LEAST SMALL CRAFT ADVISORY CRITERIA. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
1. FLOOD WARNINGS...ADVISORIES...AND/OR WATCHES ARE IN EFFECT FOR
THE AREA
2. A HIGH WIND WARNING REMAINS IN EFFECT FOR THE NORTH/CENTRAL
COAST...OLYMPICS...WESTERN STRAIT OF JUAN DE FUCA...LOWER CHEHALIS
RIVER VALLEY...AND THE NORTH/CENTRAL CASCADES UNTIL 4 PM TODAY
3. A COASTAL FLOOD WARNING REMAINS IN EFFECT FOR THE CENTRAL AND
SOUTH COAST UNTIL 6 PM TONIGHT
4. HIGH SURF WARNING REMAINS IN EFFECT FOR THE COAST UNTIL 10 PM
TONIGHT
5. WIND ADVISORY REMAINS IN EFFECT FOR THE INTERIOR LOWLANDS UNTIL
4 PM TODAY
6. A COASTAL FLOOD WATCH REMAINS IN EFFECT FOR THE NORTH COAST UNTIL
6 PM TONIGHT
7. STORM WARNING IN EFFECT FOR THE COASTAL WATERS AND WESTERN STRAIT
OF JUAN DE FUCA
8. GALE WARNING IN EFFECT FOR THE REMAINING WATERS
$$
WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION...DELAYED
NWS SEATTLE WA
937 AM PST MON DEC 3 2007
PRODUCT IS DELAYED DUE TO INCLEMENT WEATHER. ESTIMATED TIME OF
ISSUANCE 1015 AM PST.
.SYNOPSIS...A VERY STRONG COLD FRONT WILL MOVE ACROSS WESTERN
WASHINGTON TODAY. STRONG WINDS IN MANY AREAS AND HEAVY RAIN WILL
DECREASE AFTER THE COLD FRONT MOVES INLAND THIS EVENING. THE
ASSOCIATED UPPER LEVEL TROUGH WILL KEEP THE RAIN GOING AS IT
APPROACHES THE AREA TONIGHT. SHOWERS WILL DEVELOP LATE TUESDAY
BEHIND THE TROUGH. WEAKER WEST TO NORTHWEST FLOW ALOFT WILL DEVELOP
WEDNESDAY THROUGH NEXT WEEKEND ALLOWING MORE NORMAL WEATHER WITH
WEAK WEATHER SYSTEMS BRUSHING THE AREA.
&&
.SHORT TERM...TIME FOR JUST THE HIGHLIGHTS. A FRONTAL WAVE HAS BEEN
PROCEEDING NORTH ALONG THE COAST AND HAS REACHED CAPE FLATTERY.
HIGHEST WINDS AT KHQM WERE 81 MPH AT 1 AM BEFORE THE OB WAS LOST.
925 MB WINDS FORECAST UP TO 90 KT SO UPDATED THE WIND WARNING TO
INCREASE POSSIBLE GUSTS ALONG THE COAST UP TO 100 MPH. COASTAL WINDS
EXPECTED TO BACK OFF A NOTCH BY 15Z. NAM12 SHOWS A WEAKER SURGE THIS
AFTERNOON SO THE WINDS MAY GO DOWN FOR A WHILE THROUGH LATE MORNING
THEN POP-UP BRIEFLY AND NOT AS STRONG AROUND MIDDAY.
INLAND WINDS...THE MESO LOW OVER THE NE OLYMPICS HAS BEEN SLOW TO
FORM. WINDS HAVE INCREASED BUT HAVEN`T EVEN REACHED ADVISORY
CRITERIA YET. THE HIGH WIND WARNING FOR THE EVERETT-ADMIRALTY INLET
AREA DOESN`T LOOK GOOD AT THIS POINT...AND NEITHER DOES THE WIND
ADVISORY FOR PUGET SOUND SOUTHWARD. NAM12 SHOWS A PEAK IN THE
GRADIENT AROUND THE MESO LOW ABOUT 15Z SO PARTS OF THE AREA MAY
STILL REACH ADVISORY LEVELS. WITH THE WARNINGS/ADVISORIES ALREADY UP
IT WOULD BE FOOLISH TO DROP THEM BEFORE THE PEAK...SO WILL LET
THINGS RIDE. DAY SHIFT WILL PROBABLY HAVE TO DROP THEM LATER THIS
MORNING.
ACARS DATA SHOWS WINDS ALOFT SCREAMING...85 KT AT 850 MB. NOT MUCH
WIND DATA FOR THE MOUNTAINS BUT WITH WINDS ALOFT THAT STRONG...HIGH
WINDS ARE STILL A GOOD BET.
SNOW IN THE PASSES...ACARS DATA ALSO SHOWS THE FREEZING LEVEL UP TO
8000 FEET...SO HEAVY RAIN IS FALLING OVER MOST OF THE CASCADES.
HOWEVER THE PASSES STILL HAVE EAST WINDS...NEAR OR SUB-FREEZING
TEMPERATURES...AND CONTINUING HEAVY PRECIP. ROAD REPORTS SHOW
SNOQUALMIE HAS SWITCHED TO RAIN...BUT IT IS STILL SNOWING HARD AT
STEVENS. WILL EXTEND THE WINTER STORM WARNING UNTIL 4 PM THIS
AFTERNOON JUST TO BE SAFE. STEVENS MAY SWITCH TO RAIN BEFORE
THEN...BUT THEN AGAIN MAYBE NOT. STRONG WINDS ALSO CONTRIBUTE TO THE
WINTER STORM CRITERIA.
MODELS SHOW THE MAIN FRONT PASSING THE COAST AROUND 00Z. POPS REMAIN
HIGH TONIGHT THOUGH. THE HIGHEST QPF SHOULD CONTINUE OVER THE NORTH
INTERIOR UNTIL THE UPPER LEVEL TROUGH AND MAIN SURFACE LOW MOVE EAST
OF THE AREA MIDDAY TUESDAY. MUCH CALMER WEST FLOW WITH JUST SHOWERS
AROUND THE AREA TUESDAY NIGHT/WEDNESDAY. KAM
.LONG TERM...GFS SHOWS AN UPPER LEVEL RIDGE BUILDING W OF B.C.
WEDNESDAY...AND SHOWS IT STRONG ENOUGH BY THURSDAY FOR DRY NW FLOW
TO DEVELOP OVER W WA. MAY BE BE POSSIBLE TO DROP THE SHOWERS AND GO
WITH A DRY FORECAST AT LEAST FRIDAY AND SATURDAY. WILL LEAVE THAT
FOR THE DAY SHIFT. KAM
&&
.HYDRO...HUGE PRECIPITATION AMOUNTS EXPECTED IN THE MOUNTAINS
THROUGH TUESDAY MORNING. ACARS SOUNDINGS SHOW THE FREEZING LEVEL
OVER KSEA HAS GONE UP RAPIDLY IN THE LAST COUPLE OF HOURS TO NEAR
9000 FEET. SOUTHWEST WINDS IN THE 850-700MB LAYER RANGE FROM 80-100
KNOTS. THESE WINDS ARE NOT FORECAST TO DIMINISH UNTIL AFTER 21Z.
HEAVIEST PRECIPITATION IN THE NEXT 12 HOURS BUT MOIST WARM
SOUTHWESTERLY FLOW ALOFT CONTINUING THROUGH TUESDAY KEEPING THE
PRECIPITATION GOING ESPECIALLY IN THE MOUNTAINS. WYNOOCHEE DAM HAS
RECEIVED 2.50 INCHES OF RAIN BETWEEN 06Z-10Z. UPDATED QPF FOR OVER 6
INCHES OF RAIN IN THE OLYMPICS FOR THE 30 HOURS AND ANYWHERE FROM 4
TO 6 INCHES IN THE CASCADES. WITH THIS AMOUNT OF PRECIPITATION ALL
MAJOR STEM RIVERS IN WESTERN WASHINGTON HAVE THE POTENTIAL TO FLOOD
WITH MAJOR FLOODING POSSIBLE ON RIVERS FLOWING OFF THE OLYMPICS.
HEAVY PRECIPITATION IN THE LOWLANDS THROUGH THIS AFTERNOON AS WELL.
WILL ADD AN URBAN AND SMALL STREAM FLOOD WARNING TO THE MIX AS WELL
THIS MORNING. FELTON
&&
.AVALANCHE...EXISTING UNSTABLE SNOWPACK STRUCTURE AND INCREASING
LOADS DUE TO STRONG WINDS...VERY HEAVY SNOW THEN RAIN...AND WARMING
TREND FULLY EXPECTED TO CAUSE THE AVALANCHE CYCLE TO CONTINUE TODAY.
BACK COUNTRY TRAVEL IN AVALANCHE TERRAIN NOT RECOMMENDED TODAY.
PLEASE SEE WWW.NWAC.US FOR DETAILS. FERBER
&&
.AVIATION...ACARS SOUNDING INDICATE STRONG SLY WINDS OF 100+ KNOTS
AT 10K FT...50 KT AT 5K FT...AND 40 KT AT 3K FT. THIS WILL LIKELY
CONTINUE THROUGH 21Z...BEFORE EASING.
A MIX OF MVFR AND IFR CONDITIONS WILL PREVAIL TODAY MON WITH MORE OR
LESS CONTINUOUS RAIN...HEAVY AT TIMES.
AT KSEA...WINDS WILL LIKELY NOT INCREASE AT THE SURFACE AS MUCH AS
WAS PREVIOUSLY EXPECTED. EXPECT S/SE WIND 10 TO 15 KT. STRONG WINDS
ALOFT POSSIBLY CREATING COMPRESSION ISSUES.
MERCER
&&
.MARINE...COASTAL AND BUOY OBSERVATIONS ARE INDICATING GUSTS TO 75
KT THIS MORNING. A HURRICANE FORCE WIND WARNING IS NOW IN EFFECT FOR
THE COASTAL WATERS TODAY. STRONGEST WINDS WILL EASE SOMEWHAT LATER
IN THE MORNING BUT REMAIN QUITE STRONG. GALE WARNINGS WILL BE IN
EFFECT FOR ALL OTHER WATERS...ALTHOUGH IT IS SOMEWHAT UNCERTAIN THAT
THIS WILL MATERIALIZE. IN ADDITION...COMBINED SEAS WILL BUILD CLOSE
TO 40 FT WITH SEVERE BAR CONDITIONS...HIGH SURF...AND POSSIBLE
COASTAL FLOODING.
MERCER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
.HIGH WIND WARNING THROUGH 4 PM FOR THE CENTRAL AND NORTH
COAST...EASTERN AND WESTERN STRAIT AREA...ADMIRALTY INLET AREA...
HOOD CANAL AREA...EVERETT AND VICINITY...LOWER CHEHALIS VALLEY AREA.
.HIGH WIND WATCH THROUGH 4 PM CASCADES AND OLYMPICS.
.WIND ADVISORY ALL OTHER LOWLAND ZONES.
.FLOOD WATCH MOST OF WESTERN WASHINGTON.
.WINTER STORM WARNING FOR THE CASCADE PASSES.
.COASTAL FLOOD WATCH TODAY FOR THE NORTH COAST.
.COASTAL FLOOD WARNING FOR THE CENTRAL COAST.
.HIGH SURF WARNING TODAY FOR THE COAST.
.HURRICANE FORCE WIND WARNING COASTAL WATERS TODAY.
.STORM WARNING WEST ENTRANCE STRAIT OF JUAN DE FUCA.
.GALE WARNING ALL REMAINING WATERS TODAY.
.SMALL CRAFT ADVISORY ROUGH GRAYS HARBOR BAR.
$$
WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION...DELAYED
NWS SEATTLE WA
1128 AM PST MON DEC 3 2007
.SYNOPSIS...A POWERFUL STORM SYSTEM HEADING NORTHEAST TOWARD BRITISH
COLUMBIA WILL BRING HEAVY RAINS TO THE AREA ALONG WITH DAMAGING
WINDS TO THE COAST TODAY. THE STEADY RAIN WILL TAPER OFF TO SHOWERS
TONIGHT ONCE THE COLD FRONT MOVES THROUGH. MOIST...ONSHORE FLOW WILL
KEEP THE WEATHER UNSETTLED ON TUESDAY.
&&
.SHORT TERM...
VERY BUSY THIS MORNING WITH FLOODING AND HIGH WINDS. HIGH WINDS
CONTINUED OVER THE COAST AND OLYMPICS THIS MORNING...WITH WINDS
GUSTING AS HIGH AS 93 MPH AT SEKIU EARLIER TODAY. ELSEWHERE WINDS
WERE MUCH LIGHTER...THUS HAD DOWNGRADED THE HIGH WIND WARNING ISSUED
EARLIER FOR THE HOOD CANAL AREA...ADMIRALTY INLET...ERN STRAIT OF
JUAN DE FUCA...AND EVERETT AND VICINITY. FOR THE MOST PART...THE
STRONGEST WINDS WILL BE OVER THE COAST AND OLYMPICS TODAY.
CONCERNING FLOODING...URBAN/SMALL STREAM FLOOD WARNINGS ARE POSTED
FOR THE ENTIRE AREA DUE TO THE HEAVY RAINS. 10-15 OLYMPICS AND SW
PART OF THE CWA WITH LESSER...BUT STILL SIGNIFICANT...AMOUNTS
ELSEWHERE. RAIN...HEAVY AT TIMES...WILL PERSIST BEFORE GRADUALLY
DECREASING LATER TODAY.
.LONG TERM...FROM THE PREV DISCUSSION...GFS SHOWS AN UPPER LEVEL
RIDGE BUILDING W OF B.C. WEDNESDAY...AND SHOWS IT STRONG ENOUGH BY
THURSDAY FOR DRY NW FLOW TO DEVELOP OVER W WA. MAY BE BE POSSIBLE TO
DROP THE SHOWERS AND GO WITH A DRY FORECAST AT LEAST FRIDAY AND
SATURDAY. WILL LEAVE THAT FOR THE DAY SHIFT. KAM
&&
.HYDRO...FROM THE PREV DISCUSSION...HUGE PRECIPITATION AMOUNTS
EXPECTED IN THE MOUNTAINS THROUGH TUESDAY MORNING. ACARS SOUNDINGS
SHOW THE FREEZING LEVEL OVER KSEA HAS GONE UP RAPIDLY IN THE LAST
COUPLE OF HOURS TO NEAR 9000 FEET. SOUTHWEST WINDS IN THE 850-700MB
LAYER RANGE FROM 80-100 KNOTS. THESE WINDS ARE NOT FORECAST TO
DIMINISH UNTIL AFTER 21Z. HEAVIEST PRECIPITATION IN THE NEXT 12
HOURS BUT MOIST WARM SOUTHWESTERLY FLOW ALOFT CONTINUING THROUGH
TUESDAY KEEPING THE PRECIPITATION GOING ESPECIALLY IN THE MOUNTAINS.
WYNOOCHEE DAM HAS RECEIVED 2.50 INCHES OF RAIN BETWEEN 06Z-10Z.
UPDATED QPF FOR OVER 6 INCHES OF RAIN IN THE OLYMPICS FOR THE 30
HOURS AND ANYWHERE FROM 4 TO 6 INCHES IN THE CASCADES. WITH THIS
AMOUNT OF PRECIPITATION ALL MAJOR STEM RIVERS IN WESTERN WASHINGTON
HAVE THE POTENTIAL TO FLOOD WITH MAJOR FLOODING POSSIBLE ON RIVERS
FLOWING OFF THE OLYMPICS. HEAVY PRECIPITATION IN THE LOWLANDS
THROUGH THIS AFTERNOON AS WELL. WILL ADD AN URBAN AND SMALL STREAM
FLOOD WARNING TO THE MIX AS WELL THIS MORNING. FELTON
&&
.AVALANCHE...FROM THE PREV DISCUSSION...EXISTING UNSTABLE SNOWPACK
STRUCTURE AND INCREASING LOADS DUE TO STRONG WINDS...VERY HEAVY SNOW
THEN RAIN...AND WARMING TREND FULLY EXPECTED TO CAUSE THE AVALANCHE
CYCLE TO CONTINUE TODAY. BACK COUNTRY TRAVEL IN AVALANCHE TERRAIN
NOT RECOMMENDED TODAY. PLEASE SEE WWW.NWAC.US FOR DETAILS. FERBER
&&
.AVIATION...A STRONG PACIFIC SYSTEM LOCATED OFFSHORE WILL CONTINUE
TO TRACK NORTHEAST TODAY WITH MODERATE RAINFALL CONTINUING ACROSS
WESTERN WASHINGTON. STRONG SOUTHERLY FLOW AT THE SURFACE WILL
PRODUCE SOME HEAVY SHOWERS ACROSS THE AREA WHICH WILL KNOCK
VISIBILITY AND CEILINGS DOWN TO IFR CONDITIONS. ALOFT...ACARS
SOUNDINGS SHOW STRONG SW WINDS WITH 50-60KTS AT 5K FT AND 10K FT
THIS MORNING...ALTHOUGH MODEL SOUNDINGS SHOW SW WINDS INCREASING TO
NEAR 100KTS AT 5K THIS AFTERNOON AS 150KT JET SLIDES OVER THE AREA.
IN GENERAL...WINDS AND RAIN WILL DECREASE IN INTENSITY LATER THIS
EVENING AS THIS SYSTEM TRACKS FURTHER N INTO BC.
.KSEA...EXPECT MODERATE TO HEAVY SHOWERS TO CONTINUE THROUGH THE
AFTERNOON AND EVENING. STRONG SHOWERS MAY LOWER THE VIS AND CIGS
DOWN TO IFR CONDITIONS. TEMPS ALOFT ARE FAIRLY WARM AND NOT
EXPECTING ANY THUNDER. WINDS AT THE SURFACE WILL PICK UP TO 15 TO
25KTS THIS AFTERNOON...WITH STRONGER WINDS ALOFT TO NEAR 100KT UP AT
5K FT AS JET STREAK MOVES OVER THE AREA. 33
&&
.MARINE...A VERY STRONG 965 MB SURFACE LOW LOCATED NEAR 45N AND 140W
WILL TRACK NE THIS AFTERNOON AND EVENING TOWARD THE QUEEN CHARLOTTE
ISLANDS. THIS SYSTEM PRODUCED VERY STRONG WINDS EARLIER IN THE
MORNING UP TO HURRICANE FORCE...HOWEVER THE WINDS...ALBEIT STILL
STRONG...HAVE DECREASED DOWN TO STORM FORCE. COMBINED SEAS SHOW 30
TO 35 FEET. ACROSS...THE INLAND WATERS...EXPECTING GALE FORCE WINDS
TO DEVELOP THIS AFTERNOON AS THIS SYSTEM TRACKS CLOSER TO THE AREA.
WINDS ARE EXPECTED TO DECREASE LATER THIS EVENING BUT WILL MAINTAIN
AT LEAST SMALL CRAFT ADVISORY CRITERIA. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
1. FLOOD WARNINGS...ADVISORIES...AND/OR WATCHES ARE IN EFFECT FOR
THE AREA
2. A HIGH WIND WARNING REMAINS IN EFFECT FOR THE NORTH/CENTRAL
COAST...OLYMPICS...WESTERN STRAIT OF JUAN DE FUCA...LOWER CHEHALIS
RIVER VALLEY...AND THE NORTH/CENTRAL CASCADES UNTIL 4 PM TODAY
3. A COASTAL FLOOD WARNING REMAINS IN EFFECT FOR THE CENTRAL AND
SOUTH COAST UNTIL 6 PM TONIGHT
4. HIGH SURF WARNING REMAINS IN EFFECT FOR THE COAST UNTIL 10 PM
TONIGHT
5. WIND ADVISORY REMAINS IN EFFECT FOR THE INTERIOR LOWLANDS UNTIL
4 PM TODAY
6. A COASTAL FLOOD WATCH REMAINS IN EFFECT FOR THE NORTH COAST UNTIL
6 PM TONIGHT
7. STORM WARNING IN EFFECT FOR THE COASTAL WATERS AND WESTERN STRAIT
OF JUAN DE FUCA
8. GALE WARNING IN EFFECT FOR THE REMAINING WATERS
$$
WEATHER.GOV/SEATTLE
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