619
FXUS61 KPHI 090848
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
348 AM EST TUE FEB 9 2010
SYNOPSIS
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. COMPLEX LOW PRESSURE WILL
APPROACH FROM THE SOUTHWEST THIS AFTERNOON AND CONSOLIDATE AND
INTENSIFY OFF THE NORTHERN MID ATLANTIC COAST BY WEDNESDAY MORNING.
THE LOW WILL LIFT AWAY WEDNESDAY NIGHT AND THURSDAY...AND HIGH
PRESSURE WILL APPROACH FOR THE END OF THE WORK WEEK.
NEAR TERM /THROUGH WEDNESDAY/
HERE/S THE WEATHER HEADLINE SYNOPSIS...THE WINTER STORM WARNING WILL
CONTINUE...AS WILL THE WIND ADVISORY. A BLIZZARD WARNING WILL NOT
BE ISSUED NOW FOR WEDNESDAY (AFTERNOON) AS CONFIDENCE IS NOT HIGH
ENOUGH...BUT ONE MAY BE NEEDED AS THE EVENT UNFOLDS. FOR THE FAR
SOUTHEAST...LIGHT MIXED PRECIPITATION LATER THIS AFTERNOON INTO
THIS EVENING COULD CHANGE TO RAIN...SO A WINTER WEATHER ADVISORY
WAS ISSUED THERE...BUT WITH SNOW EXPECTED TO DEVELOP ON THE BACK
SIDE WEDNESDAY AND REACH WARNING AMOUNTS...A WINTER STORM WARNING
WAS ALSO ISSUED STARTING AT 7 AM (WHICH MAY BE A LITTLE EARLY).
HIGH CLOUDS WILL INCREASE THIS MORNING AND THICKEN AND LOWER THIS
AFTERNOON AS THE DEVELOPING LOW PRESSURE SYSTEM ADVANCES TOWARD
OUR AREA FROM THE SOUTHWEST. MODEL GUIDANCE THIS MORNING HAS BEEN
SOMEWHAT LESS THAN IN GREAT AGREEMENT...ESPECIALLY REGARDING LOW
LEVEL THERMAL PROFILES AND THICKNESSES. HPC FAVORS THE GFS/UKMET
SOLUTION...AS THE NAM SOLUTION WAS THOUGHT TO BE SLIGHTLY TOO FAR
NORTH AND HENCE TOO WARM WITH ITS THERMAL FIELDS. THE ECMWF WAS
MORE IN LINE WITH THE GFS. EVEN SO...WITH THE ONSHORE WINDS KICKING
IN...THE THERMAL FIELDS CLOSER TO THE COAST WERE HEDGED SLIGHTLY
TOWARD THE NAM. THIS MEANT THAT THE WEATHER GRIDS WERE NOT CHANGED
MUCH...AS MIXED PRECIPITATION HAD BEEN MENTIONED IN SOUTHERN NEW
JERSEY AND SOUTHERN DELAWARE. RAIN WAS BROUGHT IN TO THE SOUTHERN
COASTAL AREAS FOR A TIME TONIGHT.
PRECIPITATION IS EXPECTED TO START SOUTH LATER THIS AFTERNOON AND
NORTH THIS EVENING. NO SIGNIFICANT CHANGES WERE MADE TO THE
PHILOSOPHY OF THE PREVIOUS PACKAGE...WITH ONE EXCEPTION. THAT WAS
TO INCREASE QPF AND HENCE SNOW AMOUNTS NORTH AND EAST OF THE
PREVIOUSLY FORECAST MAXIMUM SNOW AREA WHICH WAS OVER NORTHEASTERN
MARYLAND. THIS WAS DUE TO THE TRACK OF THE 850 HPA LOW...WHICH
WOULD SUGGEST A BROAD-ISH BAND ALONG THE I-95 CORRIDOR
NORTHEASTWARD TOWARD NEW YORK CITY. THIS ALSO CORRELATES WELL WITH
HPC/S SOLUTION. 12 TO 16 INCHES WAS FORECAST FOR THE AXIS OF THIS
BAND...WITH AMOUNTS FALLING OFF EITHER SIDE...LOWEST FAR SOUTHEAST
WHERE MIXED PRECIPITATION WILL KEEP AMOUNTS DOWN...PERHAPS TO THE
3 TO 6 INCH...OR 4 TO 8 INCH...RANGE. THESE AMOUNTS WERE DECIDED
UPON BASED ON MODEL QPFS OF ABOUT 10 TO 12 INCHES...AND ADJUSTING
UPWARD MAINLY IN THE HIGHER-BAND AREA FOR RATIO CONSIDERATIONS. A
FEW SPOTS MAY GET UP TO 18 INCHES, SO A GENERAL 10 TO 18 INCH
MENTION WAS MADE IN THE BODY OF THE WARNING PRODUCT MESSAGE.
SNOW TONIGHT IS SOMEWHAT MORE LIKELY FOR THE SOUTHWESTERN PART OF
OUR SERVICE AREA...WITH THE NEXT SURGE DURING WEDNESDAY FURTHER
NORTH AND EAST WITH THE UPPER LOW AND THE WRAP-AROUND ASSOCIATED
WITH THE SURFACE LOW.
WITH WARMER AIR CAUSING PRECIPITATION TO MIX AND LIKELY CHANGE TO
RAIN OVER THE FAR SOUTHEASTERN ZONES WHERE THE WINTER STORM WATCH
HAD BEEN CONTINUED...IT WAS DECIDED TO ISSUE AN ADVISORY FOR
NUISANCE PRECIPITATION THIS AFTERNOON AND EVENING AND WAIT UNTIL
THE REAL DEVELOPING SNOW FOR WEDNESDAY FOR THE WINTER STORM
WARNING...WHICH COULD DEPOSIT A GOOD SWIPE ON THE BACK SIDE (OF
THE STORM). THE WATCH THERE IS NO LONGER IN EFFECT.
WINDS WILL INCREASE STRONGLY LATER WEDNESDAY MORNING AND WEDNESDAY
AFTERNOON ESPECIALLY ALONG THE COASTAL ZONES...AND WILL CONTINUE
INTO WEDNESDAY EVENING UNTIL THE STORM STARTS TO PULL AWAY. THE
WIND ADVISORY WAS LEFT INTACT, ALTHOUGH THOUGHT WILL NEED TO BE
GIVE TO EXPANDING OR UPGRADING TO A BLIZZARD WARNING AS THERE IS
A POTENTIAL THAT THE STORM COULD BE STRONGER THAN PRESENTLY
FORECAST.
SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/
THE WINTER STORM EVENT WILL BE ENDING DURING WEDNESDAY NIGHT...
PROBABLY FAIRLY EARLY...WITH MODEL GUIDANCE IN AGREEMENT ON THE
EXIT TIMING OF THE STORM. STRONG WINDS WILL REMAIN BEHIND THE
SYSTEM...AND THE WIND ADVISORY MAY NEED TO BE EXTENDED...BUT THIS
CAN BE REVISITED LATER ON.
DRY BUT WINDY WEATHER EXPECTED FOR THURSDAY FOR SNOW SHOVELING.
MODEL GUIDANCE WAS USED FOR THESE TWO PERIODS...WITH TEMPERATURE
AND WIND GUIDANCE ACCEPTABLE.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
THE CONTINUATION OF A MEAN TROUGH ACROSS EASTERN CANADA AND THE
UNITED STATES WILL KEEP BELOW NORMAL TEMPERATURES ACROSS THE AREA
DURING THE EXTENDED PERIOD. THE GOOD NEWS APPEARS TO BE THAT THE
SOUTHERN STREAM STORM TRACK WILL BE FAR ENOUGH SOUTH TO KEEP
SIGNIFICANT PRECIPITATION ACROSS THE DEEP SOUTH, WHILE ONLY ONE
NORTHERN STREAM SYSTEM WILL AFFECT OUR AREA.
A HIGH OVER THE OHIO VALLEY WILL RIDGE IN AND KEEP DRY AND COLD
WEATHER ACROSS THE AREA THURSDAY NIGHT THROUGH THE WEEKEND. EARLY
NEXT WEEK, A SHORT WAVE ACROSS THE GREAT LAKES AND LOW PRESSURE
MOVING UP THE OHIO VALLEY WILL APPROACH AND COULD POSSIBLY PRODUCE
SOME PRECIPITATION ACROSS THE AREA. I DECIDED TO KEEP THE FORECAST
DRY FOR NOW, WITH CONFIDENCE IN MEASURABLE PRECIPITATION FAIRLY
LOW.
AVIATION /08Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDS ARE FCST THRU LATE AFTN/ERLY EVENING, THEN THINGS GO
SOUTH PRETTY QUICKLY. THIS IS BEGINNING TO SOUND LIKE A BROKEN
RECORD, BUT ANOTHER WINTER STORM IS EXPECTED TO IMPACT THE AREA
LATER THIS AFTN INTO ERLY THURS MORNING. VERY POOR FLYING CONDITIONS
ARE ANTICIPATED. THERE MAY BE SOME LIGHT SNOW LATE IN THE DAY AROUND
21/22Z, BUT WE EXPECT THE MAJORITY OF THE SNOW TO MOVE IN AFTER 00Z
WHICH WILL THEN LOWER CIGS AND VSBYS. EXPECT WIDESPREAD IFR/LIFR
THROUGH AT LEAST WEDNESDAY NIGHT WITH SNOW FALLING HEAVY AT TIMES.
ACRS THE EXTREME SE, MAINLY FOR KACY AND KMIV, THERE COULD BE SOME
MIXED PRECIPITATION OR EVEN PLAIN RAIN AT THE ONSET, BUT THEY ARE
EXPECTED TO GO OVER TO MAINLY OR ALL SNOW OVERNIGHT.
OUTLOOK...
THE AFOREMENTIONED WINTER STORM WILL CONTINUE IN THE EXTENDD PERIOD
WINDS WILL ALSO INCREASE DURING THE DAY ON WEDNESDAY AND COULD GUST
AS HIGH AS 30 KT WEDNESDAY AFTN AND EVENING, MAINLY FROM THE N THEN
NW. HIGH PRESSURE WILL THEN BUILD IN FOR THURSDAY THROUGH THE END
OF THE WEEK, BRINGING A RETURN TO VFR CONDS AND MUCH BETTER FLYING
WX.
MARINE
ANOTHER SIGNIFICANT STORM WILL AFFECT THE COASTAL WATERS LATER TODAY
THROUGH LATE WEDNESDAY. HOWEVER, THINGS WILL START OFF RELATIVELY
QUIET. THEN, AN AREA OF LOW PRESSURE IS EXPECTED TO MOVE INTO THE
OHIO VALLEY AND ANOTHER, STRONGER STORM, WILL DEVELOP NEAR THE NC
CST AND MOVE NWD TO NEAR THE NJ CST AND RAPIDLY INTENSIFY.
THEREFORE, THE WINDS ARE EXPECTED TO INCREASE MARKEDLY ON WEDNESDAY
INTO WEDNESDAY NIGHT AND CONTINUE INTO THURSDAY. WAVES WILL ALSO BE
BUILDING THROUGH THE PD. WE WILL GO WITH GALE WARNINGS OUT OF THE
GATE, BEGINNING AT 11Z WEDNESDAY AND CONTINUING UNTIL 11Z THURSDAY
ON ALL WATERS. WITH THE RAPIDLY INTENSIFYING LOW, IT APPEARS THAT
STORM CRITERIA WILL BE MET AS WELL. FOR NOW, WILL CARRY A STORM
WATCH FROM 18Z WEDNESDAY UNTIL 11Z THURSDAY ON ALL WATERS EXCEPT FOR
UPPER DEL BAY. BOTH WINDS AND WAVES WILL BEGIN TO DIMINISH ON
FRIDAY AND INTO THE WEEKEND, BUT COULD STILL BE CLOSE TO SMALL CRAFT
ADVISORY CRITERIA.
TIDES/COASTAL FLOODING
WITH ANOTHER COASTAL STORM EXPECTED TO IMPACT THE AREA LATE TUESDAY
THROUGH LATE WEDNESDAY, WINDS AND SEAS WILL BE INCREASING WHICH WILL
IN-TURN MAKE TIDES MUCH HIGHER THAN THE ASTRONOMICAL TIDE FORECASTS.
ON TOP OF THE STORM, WE ARE APPROACHING NEW MOON ON SATURDAY, SO
ASTRONOMICAL TIDES ARE QUITE HIGH. NONETHELESS, IT STILL LOOKS LIKE
WITH THE STORM BEGINNING ITS RAPID INTENSIFICATION ON WEDNESDAY
MORNING, WE MAY BE OK FOR THE MORNING HIGH TIDE. THE LOCATION THAT
WILL BE CLOSEST TO REACHING MINOR TIDAL FLOODING ON WEDNESDAY
MORNING IS LEWES, BUT CURRENT FCSTS STILL INDICATE IT WILL BE BELOW
CRITERIA, BUT THIS WILL HAVE TO BE WATCHED. THE WEDNESDAY AFTN HIGH
TIDE IS THE LOWER OF THE TWO HIGH TIDES AND IS NOT EXPECTED TO CAUSE
PROBLEMS. HOWEVER, BY THURSDAY MORNING, MOST, IF NOT ALL OF THE
OCEAN SITES ARE EXPECTED TO BE AOA CRITERIA FOR MINOR TIDAL
FLOODING, BUT IT IS TOO EARLY TO ISSUE ANY HEADLINES ATTM. ALSO,
BASED ON CURRENT FCSTS, NO LOCATION IS EXPECT TO APPROACH MODERATE.
PHI WATCHES/WARNINGS/ADVISORIES
PA...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST
WEDNESDAY NIGHT FOR PAZ054-055-060>062-067>071.
NJ...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NJZ001-007>010-012>022-026-027.
WIND ADVISORY FROM 10 AM WEDNESDAY TO MIDNIGHT EST WEDNESDAY
NIGHT FOR NJZ013-014-020>027.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR NJZ023>025.
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NJZ023>025.
DE...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST
WEDNESDAY NIGHT FOR DEZ001-002.
WIND ADVISORY FROM 10 AM WEDNESDAY TO MIDNIGHT EST WEDNESDAY
NIGHT FOR DEZ002>004.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
WEDNESDAY FOR DEZ003-004.
WINTER STORM WARNING FROM 7 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR DEZ003-004.
MD...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST
WEDNESDAY NIGHT FOR MDZ008-012-015-019-020.
MARINE...STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY
NIGHT FOR ANZ431-450>455.
GALE WARNING FROM 6 AM TO 1 PM EST WEDNESDAY FOR ANZ431-
450>455.
GALE WARNING FROM 6 AM WEDNESDAY TO 6 AM EST THURSDAY FOR
ANZ430.
SYNOPSIS...DELISI /
NEAR TERM... / DELISI
SHORT TERM... / DELISI
LONG TERM...O'HARA
AVIATION...NIERENBERG
MARINE...NIERENBERG
TIDES/COASTAL FLOODING...NIERENBERG
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