Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 311907
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
307 PM EDT FRI OCT 31 2014

.SYNOPSIS...
A SERIES OF LOW PRESSURE AREAS WILL ORGANIZE OFF THE MID ATLANTIC
COAST TONIGHT THROUGH SATURDAY NIGHT...AND FINALLY MOVE NORTHEAST
INTO THE CANADIAN MARITIMES SUNDAY NIGHT. HIGH PRESSURE WILL MOVE
IN FROM THE WEST ON SUNDAY AND CREST OVER THE REGION ON MONDAY. A
WARM FRONT WILL CROSS THE REGION ON TUESDAY FOLLOWED BY A COLD FRONT
ON THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THROUGH THIS AFTERNOON...SPRINKLES MAY DEVELOP MONMOUTH/OCEAN
COUNTIES...AND BECOME HEAVIER SHOWERS TOWARD 6 PM. WE SEE AN OB OF
SPRINKLES AT KWRI BUT UNSURE OF IT.

TONIGHT...STRONG 180 M HFC ASSOCIATED WITH CLOSED LOW ALOFT MOVING
DOWN INTO GA/SC EARLY SATURDAY WILL PERMIT CONSIDERABLE LIFT TO
DEVELOP IN OUR AREA LATE AS VORTICITY ALOFT STRETCHES NORTHWARD.
RAIN MAY BE BRIEFLY HEAVY AFTER MIDNIGHT. BOUNDARY LAYER APPEARS
TOO WARM FOR SNOW AND SLEET IN THE POCONOS.

GUSTY NE WINDS TO 25 MPH DEVELOP MONMOUTH COUNTY COAST AFTER MIDNIGHT.

50 50 BLENDED 12Z NCEP MOS GUIDANCE BUT TRENDED WITH THE SLIGHTLY
WARMER GFS MAV DEWPOINTS.

&&

.SHORT TERM /SATURDAY/...
PLENTY OF CYCLONIC MOIST INFLOW AND RATHER UNSTABLE SHOULD WRING
OUT PRETTY DECENT PERIODS OF RAIN THROUGH THE MIDDAY HOURS. CHILLY.

NOTING LARGE TT OF NEARLY 55C AND SWI -1C AND KI NEAR 29C LOWER PART
OF DELMARVA SATURDAY MORNING. COULD BE ISOLATED THUNDER BUT NOT IN
GRIDS.

TEMPS: LOWERED THE 50 50 BLENDED 12Z NCEP MOS GUIDANCE PER THE
12Z/31 ECMWF AND THE DRIER DEWPOINTS FILTERING SOUTH DURING THE
AFTERNOON.

GUSTY NORTH WINDS 20-30 MPH...MAY GUST 40 MPH NEAREST 2-5 MILES OF
THE COAST BUT NO WIND ADVY ATTM.

&&

.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 /19Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

REST OF TODAY...VFR CIGS OVERSPREADING AOA 3500 FT. SPOTTY MVFR
CIGS IN NJ. NORTH TO NORTHEAST WIND GUSTS INCREASING TO 15 KT LATE
THIS AFTERNOON.

TONIGHT...CIGS LOWER TO MVFR CONDS IN PERIODS OF RAIN/DRIZZLE.
CHANCE OF IFR CONDS IN NJ. N-NE WIND GUSTS 15-20 KT. CHANCE OF A
PERIOD OF HEAVY RAIN AFTER 05Z/01.

SATURDAY...MVFR CEILINGS EXPECTED ACROSS THE REGION. LOCALIZED
IFR CONDITIONS CLOSER TO THE COAST INCLUDING KACY AND KMIV AND
POSSIBLY BACK TO KPHL AND KILG DURING THE MORNING-MIDDAY IN
PERIODS OF HEAVIER 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...
TONIGHT...SCA N-NE WIND CONDITIONS DEVELOP BUT THE HEADLINE IS
SUPERSEDED BY TOMORROWS GALE WARNING.

SATURDAY...GALE CONDITIONS EXPECTED ALL WATERS BY 6PM SATURDAY
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 LATE MORNING EVEN IN DELAWARE BAY.

GALE WATCH UPPER DE BAY CHANGED TO A WARNING AT THE 330 PM ISSUANCE.

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...
A STRONG NORTHEAST FLOW ASSOCIATED WITH THE STRENGTHENING LOW
PRESSURE SYSTEM OFF THE EAST COAST WILL PRODUCE ELEVATED WATER
LEVELS DOWN THE SHORE THROUGH THE WEEKEND. CURRENT GUIDANCE SUGGESTS
MINOR TIDAL FLOODING ALONG BOTH THE NEW JERSEY AND DELAWARE COASTS
FOR SATURDAY AFTERNOON/S HIGH TIDE...AND PERHAPS AGAIN AT THE TIME
OF HIGH TIDE EARLY SUNDAY MORNING. TOTAL WATER LEVELS (ASTRONOMICAL
TIDE PLUS THE POSITIVE ANOMALIES CAUSED BY THE STORM) FROM ATLANTIC
CITY SOUTH THROUGH LEWES DE HAVE A GOOD PROBABILITY OF BEING HIGH
ENOUGH DURING SATURDAY AFTERNOON/S HIGH TIDE TO WARRANT AN ADVISORY
STATEMENT...SO ONE HAS BEEN ISSUED. RIGHT NOW CURRENT GUIDANCE
SUGGESTS THAT WHILE MINOR TIDAL FLOODING IS EXPECTED IN
MIDDLESEX...MONMOUTH...AND OCEAN COUNTIES...TOTAL WATER LEVELS WILL
PEAK JUST SHORT OF ADVISORY LEVEL CRITERIA. THIS COULD BE A CLOSE
CALL, SO RESIDENTS ALONG THE COAST SHOULD KEEP ABREAST OF UPDATED
FORECASTS AND ADVISORIES AS THIS EVENT UNFOLDS.

RIGHT NOW ELEVATED WATER LEVELS ARE ALSO EXPECTED IN THE DELAWARE
BAY, WITH POCKETS OF MINOR TIDAL FLOODING POSSIBLE AT THE TIME OF
HIGH TIDE SATURDAY AFTERNOON AND EVENING UP THROUGH REEDY POINT. NO
FLOODING IS EXPECTED AT THIS TIME IN THE TIDAL PORTIONS OF THE
DELAWARE RIVER...INCLUDING PHILADELPHIA.

NO PROBLEMS ARE CURRENTLY EXPECTED ALONG THE SHORES OF THE
CHESAPEAKE BAY AFFECTING THE MIDDLE AND UPPER PORTIONS OF THE
MARYLAND EASTERN SHORE.
&&

.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...FRANCK/JOHNSON 307
NEAR TERM...DRAG 307
SHORT TERM...DRAG 307
LONG TERM...JOHNSON
AVIATION...DRAG/JOHNSON 307
MARINE...DRAG/JOHNSON 307
TIDES/COASTAL FLOODING...MIKETTA 307






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