Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 272156
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
556 PM EDT WED MAY 27 2015

.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST AND A COLD FRONT WILL MOVE
ACROSS THE AREA THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE
REESTABLISHES ITSELF OFF THE EAST COAST FRIDAY INTO SATURDAY. A
COLD FRONT IS FORECAST TO MOVE ACROSS THE AREA SATURDAY NIGHT INTO
SUNDAY. HIGH PRESSURE WILL RETURN TO THE NORTHEAST EARLY NEXT WEEK
WHILE THE FRONT STALLS TO THE SOUTH.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
5:50 PM UPDATE...CANCELLED THE SEVERE THUNDERSTORM WATCH FOR MUCH
OF THE AREA. THIS IS FOR AREAS WEST OF THE CONVECTION AND ALSO
THE DELMARVA. MUCH OF THE COASTAL COUNTIES WERE ALSO DROPPED FROM
THE WATCH DUE TO THE STABILIZING INFLUENCE FROM THE OCEAN.

OTHERWISE, AN AREA OF HIGH PRESSURE REMAINS OFF THE EAST COAST AT
LATE-DAY, WITH AN ASSOCIATED UPPER RIDGE EXTENDING NEAR OUR
REGION AND OUT OVER THE ATLANTIC WATERS. MEANWHILE TO OUR WEST, AN
UPPER TROUGH AND ASSOCIATED SURFACE COLD FRONT EXTEND OVER THE
GREAT LAKES TO MIDWEST STATES. THERE ALSO LOOKS TO BE A LEAD UPPER
SHORTWAVE TROUGH MOVING INTO OUR REGION AS WELL AS A WEAK LEE-SIDE
SURFACE TROUGH ALONG THE APPALACHIANS TO OUR WEST, HELPING TO
CONTRIBUTE SOME ATMOSPHERIC LIFT FOR SCATTERED CONVECTION. LAPS
DATA SHOWED THAT SUFFICIENT DESTABILIZATION OCCURRED, WITH
SURFACE-BASED CAPE VALUES RANGING MOSTLY BETWEEN 1000 TO 1500 J/KG
ACROSS MOST OF THE FORECAST AREA, EXCEPT ALONG THE COAST. IN
ADDITION, MODEST SHEAR EXISTS ALONG WITH AMPLE LOW-LEVEL MOISTURE,
WITH DEW POINTS INTO THE UPPER 60S AND EVEN LOW 70S ACROSS THE
FORECAST AREA.

WITH THESE FACTORS IN MIND, WE WILL CONTINUE TO SEE A BROKEN LINE OF
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY GRADUALLY PROGRESSING
EASTWARD ACROSS THE FORECAST AREA THROUGH THE REST OF LATE-DAY AND
INTO THIS EVENING. ALONG WITH DOWNPOURS, THE MAIN CONCERN WITH ANY
STRONGER TO SEVERE STORMS WOULD BE GUSTY TO LOCALLY DAMAGING
STRAIGHT-LINE WINDS.

A WARM AND MUGGY OVERNIGHT IS EXPECTED, AND WE USED A BLEND OF
MET/MAV GUIDANCE FOR MINIMUM TEMPERATURES. OVERNIGHT LOWS WILL
MAINLY BE IN THE MIDDLE TO UPPER 60S ACROSS THE FORECAST AREA, AND
WITH AMPLE LOW-LEVEL MOISTURE REMAINING ACROSS THE REGION, SOME
PATCHY FOG IS POSSIBLE.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
DURING THE DAYTIME THURSDAY, THE PREVIOUSLY MENTIONED SURFACE COLD
FRONT IS EXPECTED TO APPROACH OUR FORECAST AREA DURING THE MORNING
AND GRADUALLY CROSS THE REGION THROUGH THE AFTERNOON TO EVENING.
SIMILAR TO WEDNESDAY, AN INCREASE IN INSTABILITY IS EXPECTED DURING
THE DAY, AND WITH THE APPROACHING FRONT AND A SHORTWAVE ALOFT ACTING
AS LIFTING MECHANISMS, MORE SCATTERED SHOWER/THUNDERSTORM ACTIVITY
IS ANTICIPATED. WE BEGIN POPS A LITTLE EARLIER IN THE DAY, DURING
THE MORNING, FOR OUR WESTERN ZONES. HIGHEST CHANCE POPS, THOUGH, ARE
FOCUSED INTO THE AFTERNOON, BEFORE DECREASING THEN INTO THE EVENING
AS THE FRONT PASSES BY TO THE EAST. MET/MAV GUIDANCE BLENDED WITH
CONTINUITY YIELDS HIGH TEMPERATURES MOSTLY INTO THE MIDDLE AND UPPER
80S FOR THE REGION.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL BE MOVING ACROSS THE AREA AT THE START OF THE
PERIOD AND COULD HAVE SOME SHOWERS AND TSTMS WITH IT. THE PRECIP
SHOULD BE WINDING DOWN EARLY IN THE PD.

ON FRI, HIGH PRES BUILDS BACK INTO THE REGION, AND DRY CONDS ARE
EXPECTED.

LOW PRES THEN ADVANCES ACRS QUEBEC ON SAT AND ITS ASSOCD CDFNT
WILL APPROACH FROM THE W ON SAT. THERE IS QUITE A BIT OF
UNCERTAINTY AS TO PRECIP CHCS ON SAT. THE GFS IS FASTER WITH THE
FRONT, AND HAS SOME PRECIP, MAINLY N. THE GFS IS SLOWER AND DRIER.
FOR NOW WILL GO WITH LOW POPS. THE GFS HAS CFP SAT NIGHT, WITH THE
ECMWF ON SUN. SHWRS/TSTMS WILL ACCOMPANY FROPA, BUT THERE STILL
REMAIN QUESTIONS AS TO THE TIMING.

THE FRONT THEN STALLS TO THE S OF THE REGION AS HIGH PRES BUILDS
OVER QUEBEC. YESTERDAY, THE MDLS HAD DRIED OUT EARLY NEXT WEEK.
NOW, THEY ARE MAKING IT WETTER. AGAIN, CONFIDENCE IS LOW AS THE
MDLS TRY TO IRON THINGS OUT. LOWERED POPS A BIT YESTERDAY, AND
RAISED THEM A BIT TODAY, BUT DON`T WANT TO MAKE ANY WHOLESALE
CHANGES. ALSO, SOME QUESTIONS REMAIN AS TO AREAL EXTENT AND
PLACEMENT OF THE PRECIP.

BY TUE, THE LOW MOVE NEWD OUT TO SEA AND PRECIP CHCS EITHER MOVE
NWD (GFS) OR DECREASE (ECMWF).

THE FCST IS CONTINGENT ON THE STALLED FRONT AND WHERE IT STALLS,
WHETHER IT WASHES OUT AND IF ANY WAVES DEVELOP UPON IT. THE MDLS
ARE HAVING A DIFFICULT TIME RESOLVING THE FCST EARLY NEXT WEEK AND
AS A RESULT, THE CONFIDENCE IN THIS FCST IS MUCH BELOW AVERAGE.
THERE WILL LIKELY BE SOME PRECIP BEYOND SUN, BUT WHERE, WHEN, AND
TO WHAT EXTENT REMAIN BIG QUESTIONS.

TEMPS LOOK TO START ABV NRML BUT CUD BE BELOW NRML ERLY NEXT WEEK
DEPENDING ON HOW THINGS PLAY OUT.

&&

.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

OVERALL, MAINLY VFR CONDITIONS ARE EXPECTED LATE-DAY AND THIS
EVENING, EXCEPT A PERIOD OF SUB-VFR IS POSSIBLE WITH ANY SCATTERED
SHOWER/TSTORM ACTIVITY. WE HAVE INCLUDED A MENTION OF THIS IN THE
TAFS AS A TEMPO GROUP, 22Z TO 01Z TIMEFRAME IN AND AROUND THE I-
95 CORRIDOR. THEREAFTER, WITH THE LOSS OF DAYTIME HEATING, WE
EXPECT ANY LEFTOVER SHWR/TSTORM ACTIVITY TO WANE AND DISSIPATE AS
IT APPROACHES THE COASTAL PLAIN, AND WITH STORMS UNLIKELY TO REACH
KACY THIS EVENING, NO MENTION WAS INCLUDED IN THE TAF.

OUTSIDE OF ANY STRONG WINDS IN TSTORMS, SOUTH-SOUTHWEST WINDS WILL
CONTINUE MOSTLY IN THE 10 TO 15 KNOT RANGE WITH SOME GUSTS NEAR 20
KNOTS POSSIBLE THROUGH THIS EVENING.

OVERNIGHT...ONCE SHWRS DISSIPATE AND END, AMPLE LOW-LEVEL MOISTURE
WILL REMAIN ACROSS THE AREA, AND GUIDANCE INDICATES MOSTLY MVFR
CONDITIONS TO DEVELOP WITH SOME LOWER CLOUDS AND PATCHY FOG. THIS
HAS BEEN INCLUDED IN THE TAFS, STARTING AROUND THE 08Z/09Z
TIMEFRAME. SOUTH-SOUTHWEST WINDS WILL DECREASE TO 5 KNOTS OR LESS.

THURSDAY...ANY LOW CLOUDS/FOG SHOULD LIFT, WITH CONDITIONS IMPROVING
BACK TO VFR BY MID-MORNING. WHILE SOME SCATTERED SHWRS/TSTORMS ARE
POSSIBLE DURING THE DAY WHICH MAY LOCALLY REDUCE CIGS/VSBYS, TIMING
AND COVERAGE OF THESE WAS TOO UNCERTAIN AT THIS TIME TO INCLUDE IN
THE TAFS. SOUTHWEST WINDS WILL GRADUALLY BECOME MORE WESTERLY AND
INCREASE TO AROUND 10 TO 12 KNOTS.

OUTLOOK...
THU NIGHT...GENERALLY VFR. SCT SHRA/TSRA EARLY. MDT CONFIDENCE.

FRI...GENERALLY VFR. ISOLATED SHOWERS/THUNDERSTORMS POSSIBLE FOR
WESTERN TAFS.

FRI NIGHT...VFR EARLY, THEN LOWERING CIGS/VSBYS POSSIBLE
OVERNIGHT. MDT CONFIDENCE.

SAT...IFR/MVFR PSBL EARLY, THEN BECOMING VFR DURING THE DAY.
SCATTERED SHRA/TSRA PSBL WHICH MAY REDUCE CIGS/VSBYS. GUSTY
SOUTH- SOUTHWEST WINDS AROUND 20 KNOTS. LOW TO MDT CONFIDENCE ON
TSRA.

SAT NIGHT-SUN...SUB-VFR CONDITIONS POSSIBLE, ESPECIALLY WITH
SHRA/TSRA. LOW TO MDT CONFIDENCE.

&&

.MARINE...
THROUGH THIS EVENING AND TONIGHT, SOME WIND GUSTS TO AROUND 25 KNOTS
ARE EXPECTED, ALONG WITH SOME WAVE HEIGHTS APPROACHING THE 4 TO 5
FOOT RANGE FOR THE COASTAL WATERS. WE THEREFORE MAINTAIN THE CURRENT
SMALL CRAFT ADVISORY THROUGH 10Z THURSDAY. THEREAFTER, WHILE SOME
WIND GUSTS TO AROUND 20 KNOTS MAY STILL OCCUR FOR THE COASTAL
WATERS, MAINLY SUB-SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED FOR
THE COASTAL WATERS AND FOR DELAWARE BAY THROUGH THURSDAY.

OUTLOOK...
THU-SAT...SUB-SCA CONDS EXPECTED, ALTHOUGH WINDS MAY GUST AROUND
20 KNOTS AT TIMES.

SAT NIGHT...SEAS MAY RETURN TO 5 FEET OR GREATER OVERNIGHT AHEAD
OF AN APPROACHING CDFNT.

SUN...SCA CONDS LIKELY WITH CFP.

&&

.RIP CURRENTS...
BASED ON OFFICE GUIDANCE, WE CONTINUE A MODERATE RISK OF RIP
CURRENTS THROUGH THIS EVENING FOR THE NJ BEACHES UNDER A BREEZY
SOUTH WIND.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...NIERENBERG
NEAR TERM...GORSE/KLINE
SHORT TERM...KLINE
LONG TERM...NIERENBERG
AVIATION...KLINE/NIERENBERG
MARINE...KLINE/NIERENBERG
RIP CURRENTS...



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