000
FXUS61 KPHI 280250
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
950 PM EST MON DEC 27 2010
.SYNOPSIS...
THE INTENSE LOW PRESSURE SYSTEM NEAR NOVA SCOTIA THIS EVENING
WILL CONTINUE TO MOVE NORTHEASTWARD. HIGH PRESSURE WILL BUILD TO
THE SOUTH OF THE AREA DURING THE MIDDLE OF THE WEEK, THEN BUILD
NORTHEAST ACROSS OUR AREA BY FRIDAY. THE NEXT LOW PRESSURE SYSTEM
IS FORECAST TO PASS WELL NORTHWEST OF THE AREA ON SATURDAY WITH
ITS ASSOCIATED COLD FRONT PASSING THROUGH THE REGION ON SUNDAY.
ANOTHER SOUTHERN PLAINS HIGH PRESSURE SYSTEM SHOULD THEN MOVE
TOWARD THE AREA ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE CENTER OF THE WINTER STORM THAT AFFECTED OUR REGION WAS
LOCATED OFF NOVA SCOTIA THIS EVENING. THE SYSTEM WILL CONTINUE TO
MOVE TO THE NORTHEAST. AS IT DOES, WIND SPEEDS WILL DECREASE
GRADUALLY. WHILE IT WILL REMAIN BRISK OVERNIGHT, WIND SPEEDS HAVE
FALLEN BELOW THE WIND ADVISORY CRITERION. AS A RESULT, THE WIND
ADVISORY HAS BEEN DISCONTINUED.
THE SKY OVER OUR REGION WAS MAINLY CLEAR AT 930 PM, WITH JUST
SOME STRATOCUMULUS OVER THE POCONOS AND NORTHERN NEW JERSEY.
LITTLE CHANGE IS EXPECTED OVERNIGHT.
TEMPERATURES SHOULD DROP INTO THE TEENS AND LOWER 20S BY
DAYBREAK.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
THE SHORT TERM WILL FEATURE A QUIET WEATHER PERIOD WITH SLOWLY
MODERATING TEMPERATURES. SINCE WE ARE ON THE SUBJECT OF
TEMPERATURES, WE WERE PRETTY CONSERVATIVE WITH MAX TEMPS INTO
THURSDAY SUSPECTING ITS GOING TO BE DIFFICULT TO OBTAIN THE HIGHER
MOS VALUES WITH THE SNOW COVER. THIS IS ESPECIALLY TRUE FROM
MORRIS SOUTHEAST INTO OCEAN COUNTIES WHERE WE WENT WELL BELOW STAT
GUIDANCE. MINS AT NIGHT AT LEAST INITIALLY WILL BE HELD HIGHER BY
THE CONTINUING WIND, BUT BY WEDNESDAY NIGHT, BARRING UNFORECAST
CLOUDS, SHOULD BE PRETTY COLD WITH HIGH PRESSURE PARKED OVER OUR
CWA. WE WENT TOWARD THE LOWER MOS GUIDANCE DATASETS FOR TUE NGT
AND NOT LOWER BECAUSE OF THE POSSIBILITY OF WIND, BUT BELOW ALL
THE GUIDANCE ON WEDNESDAY NIGHT AND CHANCES ARE NOT LOW ENOUGH.
AS FOR THE SENSIBLE WEATHER, THE RETURN FLOW CLOUDINESS SHOULD
DECREASE ON TUESDAY AS PER THE FCST WEAKENING OF THE WAA. THE LAKE
EFFECT FLOW THOUGH WILL BE ONGOING AND WE HAVE ADDED FLURRIES AND
SNOW SHOWERS TO OUR NWRN CWA. WHILE TUESDAY WILL BECOME WINDY
AGAIN, WITH THE STORM NOW HEADING TOWARD NEWFOUNDLAND AND ITS
DEEPENING IN DAYS GONE BY, PEAK WIND GUSTS SHOULD AVERAGE 10 TO 15
MPH LOWER THAN TODAY, WOULD ESTIMATE MOST PEAK WIND GUSTS BETWEEN
30 AND 40 MPH.
THE LAKE EFFECT FLOW IS EXPECTED TO BECOME MORE WESTERLY TUESDAY
NIGHT WHICH SHOULD SHUT OFF THE RESIDUALS FROM REACHING OUR NWRN
CWA. THE WRF-NMM REMAINS MORE BULLISH ABOUT TRAPPED SC THAN THE
GFS N. GOING ON MODEL TENDENCIES WE WENT TWO-THIRDS TOWARD THE
WRF-NMM SOLUTION. AS HIGH PRESSURE MOVES CLOSER TO OUR CWA ON
WEDNESDAY AND CONVECTIVE TEMPS FCST TO BE TOUGHER TO REACH, THE
FORECAST IS FOR A SUNNIER DAY. SOME CIRRUS MIGHT FLY OVER THE
SURFACE RIDGE ON WEDNESDAY NIGHT AND THURSDAY, BUT OTHERWISE
MOSTLY CLEAR/MOSTLY SUNNY SKIES WILL PREVAIL WITH CONSIDERABLY
LIGHTER WINDS BY THEN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
5-WAVE MODEL GUIDANCE SHOWS A LONG-WAVE TROUGH OVER THE INTER-
MOUNTAIN WEST STATES CORRESPONDING TO A WEAK MID-LEVEL RIDGE OVER
THE EAST COAST. THE TROUGH SHOULD BEGIN TO MOVE TOWARDS THE EAST
WHICH IN TURN WILL FLATTEN THE RIDGE OVER THE EAST AS A MORE
ROBUST REX BLOCK TRIES TO SET UP OVER GREENLAND ONCE MORE.
THE LONG-TERM BEGINS WITH SURFACE AND MID-LEVEL RIDGING NOSING
INTO THE REGION FROM THE WEST AND SLIDING TO OUR EAST LATE ON
FRIDAY. THIS WILL ALLOW FOR AN UPWARD TREND IN OUR TEMPERATURES ON
FRIDAY AND SATURDAY AS THE RETURN FLOW SETS UP AND 850MB
TEMPERATURES CLIMB TO ABOVE 0F FOR THE FIRST TIME IN QUITE A
WHILE. WE COULD COME CLOSE TO SEEING 50F ACROSS THE METRO AREA ON
NEW YEARS DAY, ALTHOUGH THIS BRIEF RESPITE IS JUST THAT...BRIEF.
LOW PRESSURE SKIRTING BY TO OUR NORTH WILL PUSH THROUGH A COLD
FRONT ON LATE SATURDAY NIGHT SPILLING INTO SUNDAY. WE COULD SEE A
MIX OF RAIN/SNOW ON SATURDAY NIGHT WHICH SHOULD THEN CHANGE OVER
TO ALL RAIN ON SUNDAY. AS THE FRONT GOES THROUGH AND MOVES
OFFSHORE WE WILL ONCE AGAIN EXPERIENCE A BRISK NORTHWEST FLOW AND
TEMPERATURES WILL DROP INTO THE 30S FOR THE REMAINDER OF THE
PERIOD. WINDS WILL PICK UP ONCE AGAIN ON SUNDAY AND MONDAY.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE GRADIENT BETWEEN THE DEPARTING (BUT STILL STRENGTHENING) LOW
PRESSURE SYSTEM AND AN INCOMING HIGH PRESSURE SYSTEM FROM THE
MISSISSIPPI RIVER VALLEY WAS PRODUCING WIND GUSTS OVER 40 KT AT
SEVERAL TAF SITES MONDAY AFTERNOON. MODELS INDICATE A VERY GRADUAL
WEAKENING OF THIS PRESSURE GRADIENT TONIGHT THROUGH TUESDAY, SO
BOTH THE SUSTAINED WINDS AND THE WIND GUSTS SHOULD ALSO GRADUALLY
WEAKEN DURING THIS SAME TIME PERIOD. ALSO, MIXING WILL DECREASE
WHICH WILL DAMPEN THE TRANSPORT OF 925H WINDS DOWN TO THE SURFACE.
SO, GUSTS SHOULD DROP TO 30 KT OR SO BY TUESDAY MORNING. WIND
DIRECTION IS EXPECTED TO REMAIN IN THE 280 TO 330 QUADRANT THROUGH
THE TAF PERIOD.
BLOWING SNOW MAY CONTINUE TO BE AN ISSUE DURING THE EVENING HOURS
BUT THEN SHOULD LESSEN AS THE WINDS VERY SLOWLY WEAKEN.
OUTLOOK...
HIGH PRESSURE WILL BUILD INTO OUR REGION FROM THE WEST AND
DOMINATE OUR WEATHER LATE TUESDAY THROUGH THE FIRST PART OF THE
UPCOMING WEEKEND.
&&
.MARINE...
WIND GUSTS OVER 34 KT ARE EXPECTED THROUGH THE OVERNIGHT HOURS AS
THE PRESSURE GRADIENT IS FORECAST TO RELAX ONLY EVER SO SLOWLY
THROUGH TUESDAY...SO GALE WARNINGS WILL REMAIN IN PLACE. THE ONE
EXCEPTION MAY BE THE UPPER DELAWARE BAY WHERE THE DAMPENING OF
TRANSPORT WINDS MAY REDUCE WIND GUSTS TO JUST BELOW GALE. LATER
SHIFTS CAN EVALUATE THIS SITUATION AND MAKE NECESSARY ADJUSTMENTS.
WAVE HEIGHTS HAVE PEAKED AND ARE EXPECTED TO GRADUALLY LOWER OVER
THE NEXT SEVERAL DAYS.
HIGH PRESSURE WILL PUSH IN FROM THE WEST TUESDAY AND DOMINATE OUR
WEATHER THROUGH THURSDAY...STILL HAVING INFLUENCE FRIDAY. WEST TO
NORTHWEST WINDS WILL CONTINUE TO GUST TO OVER 25 KNOTS THROUGH
TUESDAY, BUT MAY DROP BELOW ADVISORY CRITERIA TUESDAY NIGHT. SUB-
ADVISORY WINDS AND SEAS WERE FORECAST FOR WEDNESDAY THROUGH
FRIDAY.
&&
.TIDES/COASTAL FLOODING...
WITH THE STRONG NORTHWEST FLOW...NEGATIVE TIDAL ANOMALIES CAN BE
EXPECTED OVER THE NEXT DAY OR SO. WHILE THESE NEGATIVE ANOMALIES
ARE NOT EXPECTED TO PRODUCE BLOWOUT TIDE CONDITIONS ATTM...THE
SITUATION WILL BE MONITORED AND APPROPRIATE PRODUCTS ISSUED IF
NEEDED.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 3 PM EST TUESDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...DELISI/GIGI
NEAR TERM...IOVINO
SHORT TERM...GIGI
LONG TERM...HEAVENER
AVIATION...MIKETTA
MARINE...MIKETTA
TIDES/COASTAL FLOODING...MIKETTA
