Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 170106
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
906 PM EDT TUE SEP 16 2014

.SYNOPSIS...
WEAK HIGH PRESSURE WILL BRIEFLY AFFECT THE AREA OVERNIGHT INTO
WEDNESDAY, BEFORE A WEAK FRONTAL BOUNDARY MOVES ACROSS THE AREA
THURSDAY. HIGH PRESSURE WILL RETURN TO THE NORTHEAST THURSDAY
NIGHT INTO FRIDAY, BEFORE PUSHING OFFSHORE FRIDAY NIGHT. A COLD
FRONT IS EXPECTED TO AFFECT THE AREA LATE SUNDAY INTO EARLY
MONDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
NO BIG CHANGES WITH THIS UPDATE. SEEING SOME TYPICAL RADIATIONAL
FALL NIGHT DISCONTINUITIES WITH PRESENT TEMPS VS FORECASTS WHICH
WILL SETTLE AS WE PROGRESS OVERNIGHT. MIN TEMPS WERE KEPT CLOSE
TO PREVIOUS PROJECTIONS.

TONIGHT...CLEAR WITH A LIGHT NORTHWEST OR NORTH WIND OR CALM AS
HIGH PRESSURE SETTLES OVERHEAD. ATTM NOT EXPECTING FROST. 12Z
GUIDANCE GFS/NAM MOS GUIDANCE LOOKS TOO WARM AND MINS ABOUT THE
SAME OR A COUPLE WARMER THAN EARLY YDY...GENERALLY 40S TO AROUND
50 COUNTRYSIDE AND LOWER TO MID 50S URBAN CENTERS. ISOLATED UPPER
30S POSSIBLE NW NJ/NE PA. TEMPS TONIGHT ARE MAYBE 5 DEGREES BELOW
NORMAL.

PATCHY FOG POSSIBLE LATE PER THE UPS CROSSOVER TOOL.


&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
WEDNESDAY...LOOKS VERY NICE WITH AMPLE SUNSHINE AS WEAK HIGH PRESSURE
OVERHEAD MAINTAINS CONTROL. AFTERNOON SEA BREEZES ALONG THE COAST
OTHERWISE A LIGHT N-NE WIND DURING THE MORNING TRENDS SOUTHERLY
DURING THE AFTERNOON.

TEMPERATURES ARE STILL A COUPLE DEGREES BELOW NORMAL.

50 50 BLENDED 12Z/16 GFS/NAM MOS GUIDANCE FOR THIS PORTION OF THE
FORECAST.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
A MOSTLY DRY FORECAST TO START OUT, WITH A BETTER CHANCE OF RAIN
LATER IN THE WEEKEND.

THE WEAK HIGH PRESSURE WILL GET SQUEEZED OUT OF THE AREA WEDNESDAY
NIGHT, AHEAD OF AN APPROACHING WEAK FRONTAL BOUNDARY TO OUR
NORTHWEST. WITH PW`S BELOW AN INCH, NO PRECIPITATION EXPECTED
OVERNIGHT.

ON THURSDAY, A WEAK FRONTAL BOUNDARY MAY MOVE ACROSS THE AREA DURING
THE DAY; ALTHOUGH IT IS POSSIBLE THE SOUTHERN END OF THE FRONT MAY
WASH OUT BEFORE IT GETS HERE. THE GFS AND NAM ARE TRYING TO SQUEEZE
OUT SOME QPF AS THE SHORT WAVE/VORTICITY IMPULSE ALOFT SLIDES ACROSS
THE AREA DURING THE DAY. THERE IS NOT MUCH MOISTURE, PW`S ONLY
TOUCHING AN INCH AND DEWPOINTS IN THE MID/UPPER 40S TO LOW 50S, SO
IF ANY PRECIPITATION DID OCCUR, MOST PROBABLY WOULD NOT REACH THE
GROUND. SO FOR NOW WE INTRODUCED A CHANCE OF SPRINKLES TO THE
FORECAST.

HIGH PRESSURE IS EXPECTED TO BUILD BACK OVER THE AREA THURSDAY NIGHT
INTO FRIDAY, THEN PUSH OFFSHORE OF NEW ENGLAND FRIDAY NIGHT. WITH PW
VALUES LESS THAN ONE HALF/THREE QUARTERS, WE EXPECT A DRY FORECAST.

WITH HIGH PRESSURE OFFSHORE SATURDAY/SATURDAY NIGHT, RETURN FLOW
DEVELOPS WHICH WILL ALLOW DEWPOINTS TO BEGIN TO INCREASE ACROSS THE
AREA. THERE IS A WEAK SHORT WAVE/VORTICITY IMPULSE SATURDAY, BUT
WITH LIMITED VERTICAL MOISTURE, WE DO NOT EXPECT ANY PRECIPITATION.

ON SUNDAY, A FRONTAL BOUNDARY WILL BE APPROACHING FROM THE WEST. WE
DO NOT EXPECT THE FRONT TO MOVE INTO OUR AREA UNTIL LATER ON SUNDAY,
BEFORE MOVING ACROSS THE AREA SUNDAY NIGHT INTO EARLY MONDAY. THE
LATEST GFS AND ECMWF BOTH START TO DISSIPATE THE PRECIPITATION
BEFORE IT REACHES OUR AREA. HOWEVER, WE WILL STILL CARRY A CHANCE OF
SHOWERS SUNDAY NIGHT INTO EARLY MONDAY.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS

TONIGHT...VFR BECOMING CLEAR. LIGHT N-NW WIND. POSSIBLE SPOTTY
COUNTRYSIDE FOG NEAR SUNRISE AND USED THE UPS CROSSOVER TOOL. SO
FAR NO FOG IN THE TAFS BUT THAT MAY BE ADDED IN LATER VERSIONS.

WEDNESDAY...VFR. LIGHT N-NE WIND UNDER 10 KT BECOMES S OR SW LATE
IN THE DAY EXCEPT SE ALONG THE COASTS.

OUTLOOK...
WEDNESDAY NIGHT-FRIDAY...MOSTLY VFR, EXCEPT POSSIBLY SOME FOG
OVERNIGHT THURSDAY/FRIDAY MORNING.

FRIDAY NIGHT...LOWER CIGS AND/OR VSBYS MAY DEVELOP OVERNIGHT WITHIN
A PERSISTENT EASTERLY FLOW.

SATURDAY-SUNDAY...MOSTLY VFR DURING THE DAY. LOWER CIGS/VSBYS WITH
STRATUS/FOG DEVELOPMENT OVERNIGHT SATURDAY/SUNDAY MORNING. A COLD
FRONT APPROACHES SUNDAY NIGHT WITH RAIN AND LOWER CONDITIONS.

&&

.MARINE...
WINDS WILL TURN NW BEHIND DEPARTING COASTAL SNJ WEAK LOW PRESSURE
THIS AFTERNOON. NW WINDS COULD GUST UP TO 20 KT BUT WILL REMAIN
BELOW SMALL CRAFT ADVISORY CRITERIA. SEAS-SWELLS COULD BUILD 3 OR
4 FT TONIGHT, BUT WILL REMAIN BELOW ADVISORY CRITERIA.

FEELING SOME SUBTLE SWELL FROM DISTANT EDOUARD AT THIS TIME...14
SECOND 1 FT.

THE PRIMARY SWELL FROM EDOUARD IS STILL EAST OF 70W AND STRUGGLING
TO EDGE WESTWARD. 44066 - TEXAS TOWER BUOY 75 NM EAST OF THE NJ
COAST HAS HAD A STEADY STATE 2 FT SWELL THE PAST 24 HOURS.

WEDNESDAY...ATTM HAVE NO PLANS FOR AN SCA AND CAPPED SEAS AT 4 FT
TONIGHT AND 5 FT TOMORROW AND MY CONFIDENCE IN 5 FT SEAS TOMORROW
IS BELOW AVG. SAME PHILOSOPHY AS WRITTEN SINCE LATE YDY...A PROBABLE
HIGH BIAS IN THE GFS WW SWELL GUIDANCE FOR OUR AREA AS EDOUARD
TURNS NNE WELL E OF 70W TAKING ITS ENVELOPE OF HIGH SWELLS WITH
IT. WE`LL KNOW IF WE ARE CORRECT ON THIS THINKING AROUND 01Z/17-
TONIGHT WHEN SWELLS SHOULD BE INCREASING AT 44009 AND 44065
ACCORDING THE GFS WW FCST. THE HURRICANE MODEL IS FCSTG SEAS A
FOOT LESS THAN THE GFS.

THERE IS A CHANCE OF A NE WIND 15-20 KT AT THE ENTRANCE TO DE BAY
TOMORROW MORNING ADDING A 2 FT WW TO WHATEVER SWELL IS OUT THERE.
THAT COULD MEAN 5 FOOTERS FOR S SHORT TIME DURING THE MORNING
AROUND 10-17Z. ATTM...NO SCA BUT WILL BE REVIEWED.

IF 6 FOOT SWELLS MAKES IT TO 44066 LATE TONIGHT THEN WE WILL
PROBABLY NEED AN SCA FOR A PTN OF OUR WATERS ON WEDNESDAY.

THERE IS VERY LITTLE DATA TO CHECK OUT THERE BETWEEN EDOUARD AND
44066.

OUTLOOK...
WEDNESDAY NIGHT-THURSDAY...WINDS ARE FORECAST TO REMAIN BELOW SMALL
CRAFT ADVISORY LEVELS. HOWEVER, QUESTIONS REMAINS ON SEAS. IF
SEAS BUILD WEDNESDAY, THEY COULD LAST INTO THE EARLY PART OF
THURSDAY.

THURSDAY NIGHT-FRIDAY...WINDS MAY INCREASE CLOSE TO SMALL CRAFT
ADVISORY LEVELS BEHIND A WEAK FRONTAL BOUNDARY AS HIGH PRESSURE
BEGINS TO BUILD IN. SEAS MAY ALSO BEGIN TO BUILD FRIDAY AS AN
EASTERLY FETCH BUILDS ACROSS THE WATERS.

FRIDAY NIGHT-SATURDAY... SEAS MAY REMAIN ABOVE SMALL CRAFT LEVELS
WITHIN THE PROLONGED EASTERLY FLOW LATER FRIDAY INTO SATURDAY.

SATURDAY NIGHT INTO SUNDAY...CONDITIONS EXPECTED TO DROP BELOW
ADVISORY LEVELS, BUT WINDS MAY GUST NEAR 20 KNOTS. A COLD FRONT
APPROACHES SUNDAY NIGHT WITH RAIN AND INCREASING WINDS.

&&

.RIP CURRENTS...
GIVEN THAT SWELLS ARE EITHER LATE IN ARRIVING OR ARE VERIFYING
LOWER THAN WAVE WATCH PROJECTIONS, WE HAVE STARTED OUR RIP CURRENT
OUTLOOK FOR WEDNESDAY AS MODERATE. THE ENHANCED RIP CURRENT RISK
MAY POSSIBLY CONTINUE INTO THURSDAY.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...ROBERTSON
NEAR TERM...GIGI/DRAG
SHORT TERM...DRAG
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON
MARINE...DRAG/ROBERTSON
RIP CURRENTS...GIGI/DRAG





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