Skip Navigation Linkswww.nws.noaa.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service Forecast Office   NWS logo - Click to go to the NWS homepage
Philadelphia/Mount Holly banner image
 
 

Area Forecast Discussion
Latest Versions  [Current][-1][-2][-3][-4]



000
FXUS61 KPHI 311551
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1151 AM EDT FRI OCT 31 2014

.SYNOPSIS...
LOW PRESSURE OVER THE GREAT LAKES REGION WILL DIG SOUTHEAST THROUGH 
THE DAY TODAY, EVENTUALLY MERGING WITH AN OFF SHORE LOW TOMORROW. 
THAT STORM MOVES TO THE MARITIMES SUNDAY. HIGH PRESSURE SETTLES INTO 
THE CAROLINAS EARLY NEXT WEEK THEN SLIPS EASTWARD INTO THE CENTRAL 
ATLANTIC NEXT WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
1118 AM ESTF: LOWERED TEMPS SLIGHTLY TODAY (3 DEGREES FROM THE
PRIOR FCST DUE TO CLOUD COVER). NO OTHER CHANGES TO THE 930 AM
FCST ATTM. TEMPS SEVERAL DEGREES BELOW NORMAL. 

THESE TEMPS MAY STILL BE A DEGREE OR TWO TOO WARM.

BASICALLY CONSIDERABLE CLOUDINESS THIS AFTERNOON. SMALL CHC OF
LIGHT SHOWERS DEVELOPING ALONG THE NJ COAST DURING LATE AFTERNOON.

12Z NAM AND 12Z GFS CONTINUE TO ADVERTISE AND MAY INCREASE POPS
FURTHER FOR NJ COAST...FOR DEVELOPMENT LATE TODAY.

FROST-FREEZE: THIS MORNINGS FROST MORE EXTENSIVE THAN ANTICIPATED
IN OUR THURSDAY AFTERNOON FCST (BASICALLY A MODEL BLEND OF GUIDANCE
WHICH WAS TOO WARM BY 2-5 DEGREES). 

THERE WILL BE NO HEADLINES FOR FROST FREEZE UNTIL NEXT SPRINGS
GROWING SEASON BEGINS AS THIS FALLS GROWING SEASON HAS ESSENTIALLY
ENDED IN OUR FORECAST AREA.


TONIGHT...PROBABLY INCREASING POPS AND WIND GUSTS A BIT IN THE
1230 PM ESTF FOR TONIGHT IN NJ.

THE LOW MOVING OUT OF THE GREAT LAKES REGION WILL WEAKEN AND COMBINE 
WITH YET ANOTHER LOW SOUTH OF OUR AREA TONIGHT, WHILE THE INITIAL 
COASTAL LOW STRENGTHENS AND BEGINS MOVING NORTHWARD. AS THIS LOW 
BEGINS DRIFTING NORTHWARD, SEVERAL VORTICITY IMPULSES ALOFT AND 
PLENTY OF LOW LEVEL MOISTURE WILL LIFT NORTHWARD AND SWING ACROSS 
OUR AREA. THIS WILL LEAD TO RAINFALL DEVELOPING TO OUR SOUTH AND 
EAST OVERNIGHT THAT SHOULD SWING ACROSS OUR AREA, GENERALLY AROUND 
OR AFTER MIDNIGHT.

&&

.SHORT TERM /SATURDAY/...
WINDS WILL LIKELY BE THE MAIN STORY ON THE MARINE AND MAYBE
COASTAL REGION.   

CONTINUE TO BE CONCERNED ABOUT THE POTENTIAL FOR NEAR WIND ADVISORY
CONDITIONS ALONG THE COAST. HOWEVER, THERE ARE A FEW THINGS LIMITING
THE WIND. FIRST, THE TIGHTEST SURFACE PRESSURE GRADIENT AND
GREATEST MID LEVEL HEIGHT GRADIENT ARE NOT JUXTAPOSED EITHER
TEMPORALLY OR GEOGRAPHICALLY.

IF THE 12Z GFS IS IDENTICAL TO ITS 06Z PREDECESSOR FOR COASTAL
FLOODING SATURDAY AFTERNOON...WE WILL THEN ISSUE A CF ADVISORY AT
330 PM FOR THE SAT AFTN HIGH TIDE ALONG THE SNJ AND DE ATLC
COASTS. 

OTRW...ITS LOOKING PERIODICALLY RAINY AND CHILLY AND AM LOWER MAX
TEMPS BY 3-4 DEGREES IN THE 1230 PM FCST FOR SATURDAY PER NEW
12Z/31 GFS CONFIRMATION.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE STRONGEST GRADIENT WILL LIKELY BE OVER THE EASTERN HALF OF
THE REGION SATURDAY NIGHT INTO EARLY SUNDAY, HOWEVER AT THIS TIME
THE MID AND UPPER LEVEL TROUGH AXIS SHOULD BE BISECTING THE
REGION. ALSO A MID LEVEL INVERSION WILL LIMIT MIXING. INSTEAD, THE
STRONGEST WINDS LIKELY SUNDAY AFTERNOON INTO EARLY SUNDAY EVENING
WHEN THE TIGHTEST MID AND UPPER LEVEL HEIGHT GRADIENT WILL BE OVER
THE REGION. ALSO, 6 HR PRESSURE RISES THROUGH THIS PERIOD ARE
FORECAST TO BE BETWEEN 2 AND 6 MB, WHILE NOT NEARLY AS IMPRESSIVE
AS THE 10MB PLUS PRESSURE RISES WELL OFF THE COAST THAT THE MODELS
SHOW, IT COULD BE ENOUGH FOR A SMALL COMPONENT OF AN ISALLOBARIC
WIND. HAVING SAID ALL THAT HOWEVER, BASED ON LOCAL HIGH WIND
GUIDANCE WE STILL APPEAR TO BE ON THE LOWER END OF A WIND ADVISORY
THREAT EVEN ALONG THE COAST. THEREFORE, WILL JUST KEEP MENTION IN
THE HWO AT THIS TIME.

TEMPS...IN THE WAKE OF THE COLD FRONT ON SATURDAY, TEMPERATURES BY
SUNDAY SHOULD BE 10 TO 15 DEGREES BELOW NORMAL. THE COLDEST
WEATHER IS EXPECTED SUNDAY NIGHT WITH DECREASING WINDS AND
CLEARING SKIES. STILL EXPECTING THE VAST MAJORITY OF THE REGION TO
BE NEAR OR BELOW FREEZING SUNDAY NIGHT. 

PRECIP...MODELS ARE IN MUCH BETTER AGREEMENT OF THE TIMING OF THE
PRECIP, WHICH WILL MAINLY BE DURING THE DAY SATURDAY, WITH SOME
LINGERING INTO SATURDAY NIGHT. THROUGH THIS PERIOD, ALL OF THE
REGION IS EXPECTED TO BE WELL ABOVE FREEZING, SO PRECIP TYPE IS
EXPECTED TO BE RAIN. FROM THE MODEL SOUNDINGS, THE MELTING LAYER
THROUGH THIS PERIOD IS FORECAST TO BE AT OR ABOVE 4000 FT AGL.
WITH SUCH A DEEP WARM LAYER, EVEN FLURRIES ARE VERY UNLIKELY. 

MONDAY AND TUESDAY...SURFACE HIGH BUILDS NORTHEAST AS THE UPPER
LEVEL RIDGE SLIDES OVER THE REGION. STILL EXPECT A WARMING TREND
THROUGH THIS PERIOD DUE TO BOTH AIR MASS MODIFICATION AND
INCREASING THICKNESSES. HOWEVER, INTERESTINGLY, THE GFS IS NOW
SHOWING A MUCH MORE DRAMATIC WARMING TREND THROUGH THIS PERIOD AS
COMPARED TO YESTERDAYS RUNS, WITH HIGHS IN THE UPPER 60S POSSIBLE
BY TUESDAY.

WEDNESDAY THROUGH FRIDAY...STILL CONSIDERABLE UNCERTAINTY IF THE
COLD FRONT THAT WILL APPROACH FROM THE WEST WILL STALL WEST OF THE
REGION UNTIL LATE THURSDAY WHEN AN UPPER LEVEL TROUGH DIGS SE
TOWARD THE REGION. GIVEN THE UNCERTAINTY AND MODEL DIFFERENCES
HAVE STAYED CLOSE TO THE PREVIOUS FORECAST.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

REST OF TODAY...VFR CIGS DEVELOPING AOA 3500 FT. NORTH TO NORTHEAST
WIND GUSTS INCREASING TO 15-20 KT LATER THIS AFTERNOON.

TONIGHT...VFR CIGS LOWER TO MVFR CONDS IN PERIODS OF RAIN/DRIZZLE.
CHANCE OF IFR CONDS IN NJ. N-NE WIND GUSTS 15-20 KT.

SATURDAY...MVFR CEILINGS EXPECTED ACROSS THE REGION. LOCALIZED
IFR CONDITIONS CLOSER TO THE COAST INCLUDING KACY AND KMIV IN
PERIODS OF RAIN. GUSTY NORTH WINDS 20 TO 30 KT. 

OUTLOOK...
SATURDAY NIGHT INTO SUNDAY...CONDITIONS WILL SLOWLY IMPROVE FROM
WEST TO EAST. BREEZY NORTHERLY AND NORTHWESTERLY WINDS EXPECTED
ESPECIALLY NEAR THE COAST.

MONDAY THROUGH TUESDAY...VFR CONDITIONS EXPECTED.

&&

.MARINE...
THIS AFTERNOON...NE WIND GUSTS INCREASING TO NEAR 23 KT IN THE
NNJ WATERS AROUND 6 PM EDT WHILE GUSTS REMAIN UNDER 20 KT ELSEWHERE.

TONIGHT...SCA N-NE WIND CONDITIONS DEVELOP BUT THE HEADLINE IS 
SUPERSEDED BY TOMORROWS GALE WARNING.

SATURDAY...GALE CONDITIONS EXPECTED MOST OF THE WATERS WITH VARIOUS
STARTING TIMES. AT THIS TIME IT LOOKS LIKE MARGINAL GALE BEGINS
VICINITY 44065 (NNJ WATERS) NEAR DAYBREAK SATURDAY AND THEN SPREADS
SOUTHWARD DURING THE DAY WITH GUSTS INCREASING 5 KT EVERYWHERE
DURING THE AFTERNOON. WE MAY SEE SPOTTY GALE GUSTS DURING THE
MORNING EVEN IN DELAWARE BAY. A GALE WATCH HAS NOW BEEN ISSUED FOR
UPPER DELAWARE BAY. THAT WATCH WILL PROBABLY BE CONVERTED TO A
GALE WARNING THIS AFTERNOON.

OUTLOOK... 
SATURDAY NIGHT THROUGH SUNDAY NIGHT...GALE CONDITIONS EXPECTED ON
THE ATLANTIC WATERS AND LOWER DELAWARE BAY WITH PEAK GUSTS NEAR 45
KT. SEAS AS HIGH AS 10FT POSSIBLE ON THE ATLANTIC WATERS. ON THE
UPPER DELAWARE BAY...SMALL CRAFT ADVISORY GUSTS EXPECTED PRIMARILY
SATURDAY NIGHT INTO SUNDAY.

MONDAY...CONDITIONS SHOULD FALL BELOW SCA CRITERIA BY MONDAY
AFTERNOON.

TUESDAY...WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA CRITERIA.

&&

.TIDES/COASTAL FLOODING...
COASTAL FLOOD ADVISORY POTENTIAL FOR AT LEAST THE SNJ AND DELAWARE
WATERS SATURDAY AFTERNOON HIGH TIDE. 

AN ONSHORE COMPONENT OF THE BREEZY TO WINDY CONDITIONS ON SATURDAY
WILL LEAD TO ELEVATED WATER LEVELS THIS WEEKEND. MINOR TIDAL
FLOODING MAY OCCUR WITH THE HIGH TIDE CYCLE ON SATURDAY. IT IS
POSSIBLE BUT VERY UNLIKELY TO ALSO OCCUR WITH THE HIGH TIDE CYCLE
ON SATURDAY NIGHT.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 6 AM EDT SATURDAY TO 5 AM EST SUNDAY FOR 
     ANZ450>453.
     GALE WARNING FROM 2 PM EDT SATURDAY TO 5 AM EST SUNDAY FOR 
     ANZ431-454-455.
     GALE WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT 
     FOR ANZ430.

&&

$$
SYNOPSIS...JOHNSON
NEAR TERM...DRAG 1150
SHORT TERM...DRAG/ROBERTSON 1150
LONG TERM...JOHNSON
AVIATION...DRAG/JOHNSON 1150
MARINE...DRAG/JOHNSON 1150
TIDES/COASTAL FLOODING...






National Weather Service
Disclaimer Privacy Policy