Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 230934
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
534 AM EDT WED JUL 23 2014

.SYNOPSIS...
A COLD FRONT WILL APPROACH OUR AREA FROM THE NORTHWEST TODAY AND
CROSS THE REGION TONIGHT INTO THURSDAY MORNING.  HIGH PRESSURE
WILL BUILD IN BEHIND THE DEPARTING FRONT FOR THE END OF THE WEEK
INTO THE FIRST PART OF THE WEEKEND. THEN, A COMPLEX SYSTEM WILL
AFFECT THE REGION FOR SUNDAY INTO MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FAIR EARLY THIS MORNING...PATCHY IFR FOG/STRATUS HAS FORMED OVER
SOUTHERN DELAWARE WITH SCT CLOUDS DEVELOPING ELSEWHERE NEAR 5000
FT AS THE KI BUILDS WITH A LEADING EDGE OF INSTABILITY ALOFT.

TODAY...LITTLE CHANGE FROM PRIOR FORECASTS. MODEL GUIDANCE STATES
WIDESPREAD LOWER 90S (NEAR 18C 850 MB AND 925MB HOTTEST TEMPS ARE
JUST WEST AND NORTHWEST OF OUR FCST AREA). POCONOS AND IMMEDIATE
ATLC SHORE A BIT COOLER. ECMWF SEEMS TO HOLD BACK SLIGHTLY. THE
FCST TEMPS ISSUED AT 330 AM MAY BE A DEGREE TOO WARM.

HEAT INDEX UPPER 90S....CLOSE TO 100 BUT NO HEAT ADVY ISSUED ATTM.

TSTMS PROBABLY RESTRICTED TO NW NJ AND E CENTRAL AND NE PA AFTER
21Z...POSSIBLY A SECOND CLUSTER CROSSING CHESAPEAKE BAY PER MULTI
MODEL KI CONSENSUS? TT 48+ SWI -2 KI INCREASING TO 38C VCNTY POCS
AND E VA. APPEARS TO BE A SEE TEXT CASE...UNLIKELY SVR THROUGH 00Z
DUE TO LACK OF BULK SHEAR...500MB WINDS UNDER 30 KT AND MLCAPE
CLOSER TO 1600J.

NOTE THAT THERE SHOULD BE CU FIELDS FORMING THIS MORNING OVER NNJ
IN A LEADING EDGE AREA OF KI 33C BUT WITH LITTLE OR NO PRIMARY
FORCING...AM NOT EXPECTING TO YIELD ANY LATE MORNING TSTMS IN NNJ
AS THIS LEADING PATCH OF INSTABILITY SHOVES ENE TO LI BY 18Z.

TODAYS FCST BASIS: NAM TEMPS (50 50 BLEND OF 00Z/23 NAM METMOS AND
THE NAM 2M TEMPS). OTHERWISE...OTHER ELEMENTS A 50 50 BLEND OF
THE 00Z/23 NAM/GFS GUIDANCE IN THIS 330 AM ISSUANCE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
SLOW SEWD PROGRESS OF THE COLD FRONT INTO THE UNSTABLE AIRMASS SHOULD
YIELD BANDS OF TSTMS INTO THE NIGHT BUT NOT NECESSARILY WIDESPREAD.
ONE OR 2 TSTMS COULD BE SVR BUT BULK SHEAR FOR SVR IS MARGINAL AT
WORST AND ONLY THE TT AND SOME CAPE ALLOW FOR MODEST ISOLATED SVR
POTENTIAL.

PWAT 1.8 INCHES OFFERS A CHANCE OF NARROW PATHS OF 2 INCH RAINS
BENEATH THE BIGGEST STORMS.

LIGHTNING STRIKES MIGHT BE THE BIG PROBLEM?

FCST BASIS; 50 50 BLEND OF THE 00Z/23 GFS/NAM GUIDANCE IN THIS 330
AM ISSUANCE EXCEPT MOSTLY NAM METMOS TEMPS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE CDFNT WILL BE EXITING THE AREA ERLY THU, BUT LINGERING SHWRS
AND TSTMS ARE STILL EXPECTED WITH ANY INSTABILITY STILL AROUND.
THE BEST CHCS ARE ERLY. THEN, HIGH PRESSURE WILL BUILD IN FROM THE
W AND DOMINATE THE WX PATN THRU THE ERLY PART OF THE WEEKEND.

DRY WX IS THEN EXPECTED THRU SAT. AS THE HIGH SLOWLY MOVES EWD,
THE FLOW WILL BECOME MORE SLY AND SWLY AND EXPECT A RISE IN TEMPS
AND HUMIDITY BY THE WEEKEND.

THEN, BY SUN, AN AREA OF LOW PRESSURE NR THE GRTLKS WILL BE MOVG
EWD. WHILE ITS EXACT TRACK IS STILL A MATTER OF DEBATE BTWN THE
MDLS, THEY DO AGREE THAT THERE WILL BE SOME KIND OF DOUBLE
BARRELED-LOW STRUCTURE BY SUN NIGHT. THERE COULD BE A WK CFP WITH
THE FIRST LOW SUN NIGHT OR MON, THE MAIN CFP WILL BE MON NIGHT OR
TUE WITH THE SECOND LOW. AGAIN, THE DETAILS WILL STILL NEED TO BE
RESOLVED AT THIS TIME SCALE, BUT THE SUN INTO MON TIME FRAME COULD
BE STORMY DEPENDING ON HOW THINGS ULTIMATELY PLAY OUT.

HIGH PRES WILL BUILD IN BEHIND THIS DEPARTING CDFNT FOR TUE. TEMPS
LOOK TO BE AT OR SLIGHTLY ABOVE NRML THRU THE PD, UNTIL THE CFP ON
TUE WHEN TEMPS WILL BE BELOW NRML. EXPECT COMFORTABLE HUMIDITY
ERLY IN THE PD, THEN INCREASING HUMIDITY IN ADVANCE OF THE CFP
ERLY NEXT WEEK.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

EARLY THIS MORNING BEFORE 12Z...PRIMARILY VFR WITH SCT CLOUDS AOA
4000 FT. PATCHY 2 TO 5 MI FOG POSSIBLE IN THE COUNTRYSIDE TAF
LOCATIONS BUT CONFIDENCE IS LESS THAN IT WAS AT THIS TIME YDY.
TEMP-DEWPOINT SPREADS AT 5 AM ARE JUST TOO LARGE FOR FOG.
EXCEPTION SOUTHERN DE TO THE S TIP OF NJ WHERE IFR CIGS HAVE
RECENTLY DEVELOPED. LIGHT S-SW WIND.

TODAY AFTER 12Z...VFR SCT AOA 5000 FT. IFR CIGS MAY GRAZE KMIV
THIS MORNING TIL 13-14Z? OTHERWISE...BRIEFLY BKN CIGS NEAR 5000
FT VCNTY KABE AND KRDG THIS AFTN AND CHC OF A TSTM THERE AFTER 22Z
WITH GUSTY WEST WIND 30-40 KT. OTHERWISE NON TSTM GRADIENT WINDS
SUGGEST SW WIND GUST 17 KT THIS AFTN MOST TAF LOCATIONS.

TONIGHT...VFR CIGS WITH A BETTER CHC OF BRIEF IFR CONDS IN TSTMS.
LIGHT SW WIND SHIFT N TOWARD MORNING WHEN PATCHY IFR ST/FOG MIGHT
FORM IN THE FRONTAL ZONE OR WHERE IT RAINS THIS EVENING. STRONG
GUSTY WEST WIND IN A TSTM POSSIBLE BETWEEN 00Z AND 04Z FOR KTTN
KPNE KPHL AND KILG BUT LESS CONFIDENCE THAN FOR KABE AND KRDG
OUTLINED IN THE PREVIOUS PARAGRAPH.

OUTLOOK...
THU...MVFR AND IFR CONDITIONS AT TIMES IN SHOWERS AND
THUNDERSTORMS, ESPECIALLY EARLY. PATCHY FOG THU MORNING. MODERATE
CONFIDENCE.

THU NIGHT THROUGH SAT...MAINLY VFR UNDER HIGH PRESSURE. HIGH
CONFIDENCE.

SUN...SUB-VFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS.
MODERATE CONFIDENCE.

&&

.MARINE...
NO HEADLINES THROUGH TONIGHT.

MAINLY S-SW WIND G UNDER 20 KT SHIFT TO NORTH TOWARD DAWN THURSDAY.

WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD BE 2 TO 4 FEET. WAVES ON
DELAWARE BAY ARE EXPECTED TO BE 2 FEET OR LESS.

SCATTERED THUNDERSTORMS TONIGHT.

OUTLOOK...
THU THROUGH SAT...NO MARINE HEADLINE EXPECTED WITH HIGH PRES
OVERHEAD.

SUN...INCREASING SEAS AHEAD OF NEXT SYS MAY YIELD SCA, ESPECIALLY
N BY LATER IN THE DAY.

&&

.RIP CURRENTS...
LOW RISK TODAY EVEN IF THE CURRENT 8 SECOND PERIOD INCREASES TO
10 SECONDS FOR A 1.5 TO 2 FT SE SWELL. THE FCST WAS FACTORED WITH
A LATE AFTERNOON STRONGEST SSE WIND TO 15 KT. TO BE SAFEST...SWIM
IN LIFE GUARDED AREAS. THE NO SWIMMING SIGNS MEAN JUST THAT AND
LIKELY WERE POSTED BECAUSE OF SOME SORT OF HIGHLY ADVERSE EVENT AT
THOSE LOCATIONS IN THE PAST.

&&

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

&&

$$
SYNOPSIS...NIERENBERG
NEAR TERM...DRAG  535
SHORT TERM...DRAG
LONG TERM...NIERENBERG
AVIATION...DRAG/NIERENBERG 535
MARINE...DRAG/NIERENBERG
RIP CURRENTS...DRAG 535





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