Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 291959
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
359 PM EDT FRI MAY 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL REESTABLISH ITSELF OFF THE EAST COAST TONIGHT
INTO SATURDAY. A COLD FRONT IS FORECAST TO MOVE ACROSS OUR REGION ON
SUNDAY, THEN STALL ACROSS THE AREA MONDAY INTO TUESDAY, AS A WAVE OF
LOW PRESSURE MOVES ALONG IT. HIGH PRESSURE WILL BUILD TO OUR NORTH
EARLY NEXT WEEK, BEFORE MOVING INTO THE AREA WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AN AREA OF HIGH PRESSURE REMAINS OFF THE EASTERN SEABOARD, WITH AN
UPPER LEVEL RIDGE ALSO EXTENDING OVER THE EAST COAST STATES AND OUT
OVER THE ATLANTIC WATERS. LIGHT WINDS THROUGH THE COURSE OF THE DAY
HAVE GRADUALLY SHIFTED FROM AN EASTERLY DIRECTION TO MORE OF A
SOUTHEAST FLOW, AND SOME RETURN MOISTURE WITH DEWPOINTS SLOWLY
CREEPING UPWARD HAS BEEN OBSERVED OVER THE LAST FEW HOURS. IN
ADDITION, LAPS DATA SHOWS SOME MODEST INSTABILITY MAINLY ACROSS OUR
CENTRAL TO SOUTHERN DELMARVA ZONES, AND THIS IS WHERE WE CONTINUE
SOME LOWER POPS FOR A FEW SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM THROUGH THE REMAINDER OF LATE-DAY AND EARLY THIS
EVENING.

OTHERWISE THEN THROUGH THE OVERNIGHT, THE OTHER MAIN ELEMENT TO
WATCH WILL BE THE POSSIBILITY FOR SOME PATCHY FOG OR PERHAPS A FEW
LOWER CLOUDS TO FORM, MAINLY FROM ALONG THE COAST AND INTO EASTERN
PORTIONS OF OUR FORECAST AREA. WHILE CONFIDENCE IS ONLY MODERATE AT
BEST ON THIS OCCURRING AT THIS TIME, WE DID KEEP A MENTION OF PATCHY
FOG IN THE FORECAST FOR THESE AREAS AS LIGHT SOUTHEAST TO SOUTH
WINDS WILL CONTINUE THROUGH THE NIGHT AND DEWPOINTS RISE INTO THE
60S. OVERNIGHT MINIMUM TEMPERATURES WERE A BLEND OF MET/MAV
GUIDANCE, AND WE ANTICIPATE LOWS IN THE 60S ACROSS THE REGION.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
DURING THE DAYTIME SATURDAY, OUR FORECAST AREA WILL BE ON THE
WESTERN PERIPHERY OF LINGERING OFFSHORE HIGH PRESSURE AND AN UPPER
LEVEL RIDGE. IN ADDITION, A COLD FRONT IS EXPECTED TO BE APPROACHING
SLOWLY FROM AROUND THE EASTERN GREAT LAKES, WITH A LEE-SIDE TROUGH
POSSIBLY DEVELOPING TO THE WEST OF OUR REGION AROUND THE
APPALACHIANS. THESE FACTORS, ALONG WITH SOME INCREASING DAYTIME
INSTABILITY, WILL LIKELY BE ENOUGH FOR SOME ISOLATED TO PERHAPS
SCATTERED SHWRS/TSTORMS TO DEVELOP FROM LATE MORNING THROUGH THE
AFTERNOON. OVERALL, WE FOCUSED HIGHEST POPS ACROSS OUR WESTERN
ZONES. MUGGY CONDITIONS WILL BE FELT ACROSS THE AREA, WITH DEWPOINTS
INTO THE 60S. MAXIMUM TEMPERATURES WERE A BLEND OF MET/MAV GUIDANCE
WITH CONTINUITY, AND WE ANTICIPATE HIGHS TO REACH INTO THE 80S FOR
MOST OF THE REGION, EXCEPT SOME COOLER 70S ALONG THE COAST AND INTO
THE POCONOS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE REGION WILL BE UNDER THE INFLUENCE OF A SOUTHWEST FLOW ALOFT AS
A MID-LEVEL TROUGH TRANSITS THE GREAT LAKES AND NORTHEAST CONUS SUN
THRU WED...WHILE AN ATTENDANT COLD FRONT MOVING INTO THE REGION ON
SUN BECOMES QUASI-STATIONARY OVER THE MID ATLANTIC THRU EARLY NEXT
WEEK...AS THE TROUGH GRADUALLY AMPLIFIES CAUSING THE MID-LEVEL FLOW
TO BECOME PARALLEL TO IT. THE FLOW SHOULD BECOME MORE ZONAL WITH
WEAK RIDGING BY WED-THU...WITH FAIR WX EXPECTED TO RETURN. TEMPS...
W/THE EXCEPTION OF MON AND TUE...SHOULD BE NEAR SEASONABLE NORMALS.

THE MAIN CONCERN DURING THE LONG TERM PORTION OF THE FORECAST IS
THE POTENTIAL FOR CONVECTION ON SUN AND HEAVY RAINFALL EARLY NEXT
WEEK. A COLD FRONT WILL APPROACH SUN AFTN...WITH AN ANAFRONT-TYPE
SETUP...AS THE BULK OF THE PRECIP IS EXPECTED TO THE NORTH AND WEST.
ML CAPE VALUES REACH 2-3 KJ...WHILE THE MOST FAVORABLE BULK SHEAR
IS ALONG AND JUST WEST OF THE FRONT. MODEL SOUNDINGS INDICATE AN
ENVIRONMENT MOST FAVORABLE FOR GUSTY WINDS WITH ANY THUNDERSTORMS
THAT OCCUR. HEAVY RAINFALL IS ALSO POSSIBLE...GIVEN PWATS OF 1.5
INCHES /1-2 STD DEV ABOVE NORMAL/ AS WELL AS SLUGGISH STORM MOTION.

THE FRONT STALLS OVER THE MID ATLANTIC REGION LATE SUN/EARLY MON
AND THIS LEADS TO AN OVERRUNNING REGIME...AS LOW PRES DEVELOPS
ALONG IT DURING THE MON-TUE TIME FRAME. THE MAIN UNCERTAINTY HERE
IS WITH REGARD TO THE PLACEMENT OF THE OVERRUNNING...AS THE MODELS
TREND FURTHER NORTH...GIVEN THE TENDENCY TOWARD A MORE AMPLIFIED
TROUGH. THE POTENTIAL EXISTS FOR 1-2 INCHES OF RAINFALL...WHICH
COULD LEAD TO FLOODING PROBLEMS DUE TO DRY ANTECEDENT CONDITIONS
BUT THERE IS A HIGH AMOUNT OF UNCERTAINTY AT THIS TIME.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND

THROUGH THIS EVENING...VFR CONDITIONS WILL CONTINUE WITH LIGHT
EASTERLY WINDS BECOMING MORE SOUTHEASTERLY, MOSTLY IN THE 5 TO 8
KNOT RANGE.

OVERNIGHT...VFR CONDITIONS TO START, BUT GUIDANCE IS SHOWING THE
POSSIBILITY OF SOME FOG AND/OR LOWER CLOUDS DEVELOPING AFTER 06Z,
ESPECIALLY CLOSE TO THE COAST AND PERHAPS FARTHER INLAND AS WELL.
WHILE CONFIDENCE IN THIS OCCURRING IS SOMEWHAT HIGHER FOR TAF SITES
CLOSER TO THE COAST AND FOR MORE SHELTERED LOCATIONS, WE HAVE
INCLUDED EITHER MVFR VSBYS AND/OR CIGS FOR ALL SITES FOR A FEW HOURS
LEADING UP TO DAYBREAK SATURDAY. SOUTHEAST WINDS WILL BECOME MORE
SOUTHERLY DURING THE OVERNIGHT, MAINLY AT 5 KNOTS OR LESS.

SATURDAY...SOME SUB-VFR CONDITIONS POSSIBLE EARLY, OTHERWISE MAINLY
VFR DURING THE DAYTIME. SOME ISOLATED SHWRS/TSTORMS ARE POSSIBLE,
WHICH MAY LOCALLY REDUCE CIGS/VSBYS FOR A TIME, BUT CONFIDENCE IN
TIMING/COVERAGE WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS. SOUTH-
SOUTHWEST WINDS ARE EXPECTED IN THE 8 TO 10 KNOT RANGE, GUSTING AT
TIMES BETWEEN 15 TO 20 KNOTS.

OUTLOOK...

SAT NIGHT...MVFR POSSIBLE IN LOW CLOUDS AND FOG NEAR THE COAST...ESP
ACY AND MIV.

SUN...MVFR LIKELY IN SHRA AND TSRA DURING THE AFTN AND EVE HOURS...
OTHERWISE VFR.

SUN NIGHT THRU MON NIGHT...MVFR IN SHRA/TSRA...LOW CLOUDS...AND FOG.

TUE...MVFR IN SHRA/TSRA...WITH GRADUAL IMPROVEMENT TO VFR
POSSIBLE.

&&

.MARINE...
SUB-ADVISORY CONDITIONS WILL CONTINUE FOR THE COASTAL WATERS AND FOR
DELAWARE BAY THROUGH TONIGHT, WITH GENERALLY LIGHT SOUTHEAST WINDS
BECOMING MORE SOUTHERLY AS THE NIGHT PROGRESSES. SOME FOG MAY
DEVELOP OVER THE WATERS DURING THE OVERNIGHT AND ADVECT TO THE
COAST, CAUSING LOCALLY REDUCED VISIBILITIES.

REDUCED VISIBILITIES IN FOG IS POSSIBLE EARLY SATURDAY FOR THE
WATERS, OTHERWISE SUB-SCA CONDITIONS ARE EXPECTED THROUGH THE
MORNING. MARGINAL SCA CONDITIONS MAY BE REACHED SATURDAY AFTERNOON
AND EVENING, WITH WIND GUSTS APPROACHING 25 KNOTS, ESPECIALLY FOR
THE NORTHERN COASTAL WATERS. HOWEVER, CONFIDENCE WAS NOT HIGH ENOUGH
AT THIS TIME TO ISSUE A SMALL CRAFT ADVISORY. WE WILL ALLOW THE NEXT
SHIFT TO RE-EVALUATE INCOMING DATA.

OUTLOOK...

SAT NIGHT THRU TUE...SCA CONDITIONS POSSIBLE THRU THE ENTIRE
PERIOD...AS A COLD FRONT STALLS OVER THE WATERS ON SUNDAY AND LOW
PRESSURE DEVELOPS ALONG IT EARLY NEXT WEEK. AT THIS TIME...HIGHEST
CONFIDENCE IN SEAS MEETING SCA THRESHOLDS.

&&

.RIP CURRENTS...
NEW WEBLINK, WORKS BEST ON FIREFOX. DISPLAYS THE FCST GRAPHIC ETC.

WWW.WEATHER.GOV/PHI/SURFRIP4

UPGRADED THE RIP CURRENT RISK ALONG THE CENTRAL NJ COAST PER
OBSERVED CONCERN AND SOME DATA INDICATING POTENTIAL FOR MODERATE.

OTHERWISE, LOW RISK CONTINUES THIS AFTERNOON DELAWARE COAST AND THE
FAR NORTHERN AND FAR SOUTHERN NJ COASTS WHERE ONSHORE WINDS ARE
LIGHTER THOUGH A LITTLE CONCERNED ABOUT A 1 FOOT 12 SECOND ESE
SWELL SHOWING UP THAT COULD ELEVATE THE RISK SLIGHTLY THERE TOO.

CHILLY TO SWIM MOST OF CENTRAL AND NNJ BEACHES DESPITE ABOVE NORMAL
TEMPS ON THE LAND WITH WATER TEMPS THERE LOOKING TO BE IN THE UPPER
40S TO LOWER 50S. FURTHER S NEAR LBI...WATER TEMPS MAYBE 55 TO 60,
SNJ S OF KACY 60-65 AND THEN ALONG THE DE ATLC COAST UPPER 50S TO
MID 60S DEPENDING ON LOCATION.

THE OUTLOOK FOR SATURDAY IS LOW ENHANCED...WITH A STRONGER SOUTHERLY
WIND GUSTING TO 20 MPH DURING THE AFTERNOON. MIGHT BE A CLOSE CALL
FOR A MODERATE RISK DEPENDING ON THE SWELL SIZE. FOR NOW KEEPING
IT LOW RISK BUT NOT LOCKED INTO LOW.

&&

.CLIMATE...
MAY 2015...A TOP 5 WARMEST ON RECORD FOR LARGE PORTIONS OF OUR AREA.

ALL OVERNIGHT AND FORECAST INFORMATION CHECKED THROUGH 830 AM
TODAY - FRIDAY MAY 29.

CONSERVATIVE VALUES LISTED BELOW FROM OUR 5 AM SFT AND COOLING THE
NEAR MIDNIGHT SUNDAY NIGHT MAY 31 LOW TEMP DUE TO NLY FLOW CAA SUNDAY
EVENING.

ALLENTOWN WILL PROBABLY AVERAGE VERY CLOSE TO 65.9 OR 6 DEGREES
ABOVE NORMAL. POR BACK TO 1922.  AT LEAST 5TH WARMEST ON RECORD.
1991 67.2
2012 66.1
1944 66.0
2004 65.9


PHILADELPHIA WILL PROBABLY AVERAGE CLOSE TO 69.7 DEGREES OR 5.8
DEGREES ABOVE NORMAL.  SECOND WARMEST ON RECORD.

1991 70.8

NUMBER 3 WOULD BE 69.2 IN 2004.


ATLANTIC CITY MAY 2015 65.9 OR 66.0 OR 4.8 TO 4.9 ABOVE NORMAL
AND PROBABLE #2 OR #3 POR BACK TO 1874

2004 66.9
1991 66.0
2015


WILMINGTON DE SOLID POR BACK TO 1916 LOCKED INTO #4 WARMEST
1896 70.1
1991 69.1
2004 68.2
2015  AROUND 68.0

NO AVAILABLE MONTHLY HISTORICAL DATA FOR KMPO KGED KTTN AND KRDG.

&&

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

&&

$$
SYNOPSIS...FRANCK
NEAR TERM...KLINE
SHORT TERM...KLINE
LONG TERM...FRANCK
AVIATION...FRANCK/KLINE
MARINE...FRANCK/KLINE
RIP CURRENTS...DRAG
CLIMATE...DRAG



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