Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 250205
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
905 PM EST MON NOV 24 2014

.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION OVERNIGHT AND STALL JUST
OFFSHORE THROUGH TUESDAY...ALLOWING HIGH PRESSURE TO BRIEFLY MOVE
IN FROM THE SOUTHWEST. LOW PRESSURE WILL DEVELOP ALONG THIS STALLED
FRONT AND AFFECT THE REGION AS A STRONG NOR EASTER ON WEDNESDAY.
HIGH PRESSURE WILL MOVE IN ON THANKSGIVING AND DOMINATE UNTIL A COLD
FRONTAL PASSAGE IN THE SUNDAY AND MONDAY TIME FRAME.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE COLD FRONT CONTINUES TO MOVE TOWARD THE WESTERN PART OF THE
CWA. IT APPEARS THAT IT WILL ARRIVE ACROSS THE WRN AREAS IN AN
HOUR OR SO...THEN TAKE A FEW HOURS TO CROSS THE REST OF THE
REGION. LITTLE IN THE WAY OF CLOUDS OR PCPN IS OCCURING WITH THE
FRONT. A SEPARATE AREA OF CLOUDS AND SOME LIGHT SHOWERS HAS MOVED
NORTHWARD OVER THE DELMARVA AND INTO SRN NJ. I HAVE UPPED THE POPS
AND CLOUD COVER GRIDS IN THESE AREAS WITH THE EVENING UPDATE.
MINOR ADJUSTMENTS TO TEMPS/DEW POINTS AND WINDS.


&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
ONE LAST FAIR WEATHER DAY EXPECTED ON TUESDAY BEFORE THE UPCOMING
STORM IN THE LONG TERM. OVERALL DRY WEATHER WITH MID AND HIGH LEVEL
CLOUDS EXPECTED FOR MOST OF THE DAY. TEMPERATURES WILL BE 10-15
DEGREES COOLER WITH NORTHWEST FLOW ACROSS THE AREA AND LOWERING
THICKNESSES AND 925 MB TEMPERATURES. HIGHS WERE A BLEND OF MIXED 925
MB TEMPS, MAV/MET MOS, AND MOSGUIDE WHICH KEEPS EVERYONE ABOVE
NORMAL, BUT CLOSER THAN MONDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
**WINTER STORM/EVENT OF WET SNOW AT HAND E PA AND NW NJ**

500 MB: THE LEAD SHORT WAVE THAT PRODUCES OUR WINTER STORM WILL
BE MOVING EASTWARD ALONG THE GULF COAST TUESDAY EVENING THEN UP
THE EAST COAST LATE WEDNESDAY TO NEW ENGLAND BY THURSDAY MORNING.
IT PASSES THROUGH NJ AS AN INTENSIFYING 200M 12 HR 500MB HFC NEAR
06Z THURSDAY.

TEMPERATURES: MIN TEMPS WED MORNING WILL BE ABOUT 5 DEGREES ABOVE
NORMAL BUT THE PROBLEM IS THE HIGH TEMPERATURES AFTER DAYBREAK
WEDNESDAY WILL BE 8 TO 12 DEGREES BELOW NORMAL AS WET BULBING
OCCURS IN THE INCREASING NORTHERLY SFC FLOW. LOWS WEDNESDAY NIGHT
WILL BE NEAR OR SLIGHTLY BELOW NORMAL BUT NOT A HARD FREEZE SUBSEQUENT
TO THIS SNOW.

POPS: TUESDAY NIGHT AND WEDNESDAY NIGHT ARE BLENDED 12Z/24 NCEP MOS
THEN THAT BLENDED WITH THE 09Z/24 SREF AND 00Z-12Z ECMWF 6 HR QPF
INDICATIONS OF .10 OR GREATER.

THE STORM...

OUR RECOMMENDATION: TO REACH YOUR HOLIDAY DESTINATION ON TIME WITH
PROBABLY A MINIMUM OF WEATHER RELATED TRAVEL DELAYS...AND ESPECIALLY
TRAVELING WEST OF I-95 INTO NORTHWEST NJ...EASTERN PA...TRAVEL SHOULD
BE COMPLETED AT THE LATEST...BY 10 AM WEDNESDAY.

NORMALLY THIS STORM WOULDN`T HAVE GARNERED SO MUCH LEAD TIME ATTENTION
BUT WE RESPONDED TO THE THE HEIGHTENED PUBLIC INTEREST ON WHAT IS
USUALLY THE BUSIEST TRAVEL DAYS OF THE YEAR.

THE WATCH WAS EXPANDED TO JUST NW OF I-95 IN THE 330 PM FORECAST.

ITS POSSIBLE THAT THE SNOW AMOUNTS NEAR AND EAST OF I95 ARE A BIT
TOO LOW AND THAT THE WATCH MIGHT HAVE NEEDED A SLIGHT SEWD EXTENSION
INTO NE MD AND N DE. DEPENDS HOW FAST RAIN CHANGES TO SNOW THERE.


TUESDAY NIGHT...LEFTOVER WARMTH AND IT APPEARS THE LEADING EDGE OF
THE PCPN SHIELD WILL BEGIN AS RAIN MOST OF THE AREA EXCEPT WELL TO
THE NORTHWEST OF I-95 (HIGHER TERRAIN). NO ACCUMULATION ANTICIPATED
BEFORE 7 AM. LIGHT WEST WIND BECOMING N-NE TOWARD MORNING.

WEDNESDAY THROUGH MIDNIGHT WEDNESDAY EVENING...

THE WEDNESDAY AFTERNOON EVENING COMMUTE SHOULD BE PROBLEMATIC...ESPECIALLY
HILLS AND OVER THE KITTATINNY RIDGE IN NW NJ-POCONOS OF NE PA.

WEST OF I-95...MAINLY WHERE SOME BANDING AND ASSOCIATED SNOWFALL RATE
ENHANCEMENT IS EXPECTED ALONG THE SE EDGE OF THE COMMA HEAD (THERMAL
AXIS OF PIVA AND FGEN). ACCUMULATION HERE MAY BE MORE ON THE ORDER
OF 12 TO 1? BANDING COULD RESULT IN ISOLATED GREATER THAN 10 INCH
AMOUNTS IN THE POCONOS AND NORTHERN SUSSEX COUNTY NJ.

I-95 CORRIDOR RAIN MIXING WITH OR CHANGING TO WET SNOW DURING
MIDDAY OR EARLY AFTERNOON THEN REMAINING AS SNOW BEFORE ENDING
DURING WEDNESDAY EVENING. WHILE QPF IS GREATER HERE...SNOWFALL
SHOULD BE NOT BE GREATER THAN 10 TO 1 RATIO. SLOPPY WET SNOW THAT
COULD CLING TO TREES AND WIRES AND OBSCURE ROAD SIGNS DURING THE
AFTERNOON-EVENING IN A 32-33F SURFACE TEMPERATURE ENVIRONMENT. IF
4 TO 6 INCHES OF WET SNOW WERE TO ACCUMULATE ON BRANCHES/WIRES...THE
RISK OF BROKEN TREE LIMBS SHOULD INCREASE CONSIDERABLY. TOTALS UNKNOWN
BUT SUSPECT MAINLY 1 TO 5 INCH AMOUNTS.

ADDED A WATCH TO PHILADELPHIA AT THE LAST MINUTE JUST BEFORE 330
PM DUE TO AUTOMATED PHRASING FROM OUR FORECAST GRIDS.

COAST: RAIN POSSIBLY ENDING AS SNOW WEDNESDAY EVENING. TOTALS NIL TO
2 INCHES? NO ACCUMULATIONS DURING THE DAY AS PER THE WATER TEMPERATURE
STILL IN THE MID 50S, THE ONSHORE FLOW AND PROXIMITY OF THE WARMING
ALOFT NEAR THE SURFACE LOW AND EAST OF THE VORT PATH SHOULD KEEP
THEM WELL ABOVE FREEZING THROUGHOUT THE DAY. THE CAVEAT TO ALL OF
THIS IS THAT THE LOCATION OF THE RAIN/SNOW TRANSITION AND EVEN
SNOW RATIOS IS VERY MUCH DEPENDENT ON THE TEMPERATURE PROFILE.
THERE IS STILL MODEL DISAGREEMENT, SO SNOW AMOUNTS REMAIN UNCERTAIN
FROM I95 EASTWARD REMAIN FAR FROM CERTAIN.

THE COAST SHOULD CHANGE TO SNOW OR FLURRIES WEDNESDAY EVENING BEFORE
ENDING WHEN A SLIGHT ACCUMULATION COULD OCCUR.

PRECIPITATION EVERYWHERE MODERATE TO HEAVY FOR A TIME DURING THE
DAY WITH TAIL END SNOW IN EASTERN PA AND NW NJ POSSIBLY STILL
MODERATE DURING THE EVENING.

NORTH TO NORTHEAST WIND GUST 15-25 MPH I95 EASTWARD.

RECORD DAILY SNOWFALL IS FORECAST FOR KABE (VULNERABLE RECORD OF
1.7 INCHES) AND DITTO AT KILG WHERE THE VULNERABLE DAILY RECORD IS
0.1 INCHES.


AFTER MIDNIGHT WEDNESDAY NIGHT...JUST A SMATTERING OF FLURRIES AND
VARIABLE CLOUDINESS WITH LIGHT WIND AND TEMPERATURES NEAR FREEZING.

THURSDAY THROUGH SUNDAY...

* THANKSGIVING DAY WILL BE DRY WITH BELOW NORMAL TEMPERATURES.
* FRIDAY AND SATURDAY WILL FEATURE DRY WEATHER W/UNSEASONABLY
  COOL TEMPERATURES.
* A COLD FRONTAL PASSAGE EXPECTED IN THE SUNDAY-MONDAY PERIOD
  W/TEMPERATURES EXPECTED TO MODERATE TO SEASONABLE LEVELS.

THE MAIN CHALLENGE THURSDAY AND BEYOND WILL BE HOW THE MODELS
RESOLVE A MID-LEVEL SPLIT FLOW REGIME OVER THE EASTERN PACIFIC
AND THE TRANSITION FROM A MERIDIONAL FLOW ACROSS THE CONUS TO A
ZONAL FLOW...AS THE NAO BECOMES POSITIVE AND THE PNA BECOMES
NEGATIVE. WITH THE FLOW BECOMING ZONAL...THE MAIN UNCERTAINTY WILL
BE W/SHORTWAVE ENERGY RIDING ALONG THE US/CANADIAN BORDER OVER THE
WEEKEND...WHERE PREDICTABILITY IS LOW. THERE ARE DIFFERENCES IN
THE AMPLITUDE AND TIMING OF THIS FEATURE...WHICH TRANSLATES INTO
UNCERTAINTY W/THE TIMING OF A COLD FRONT AND TEMPERATURES...ESP
LATE IN THE WEEKEND INTO EARLY NEXT WEEK.

THURSDAY...
FLOW REMAINS CYCLONIC ALOFT WITH X-SECS INDICATING ABUNDANT
MOISTURE IN THE LOW AND MID-LEVELS...SO EXPECTING CONSIDERABLE
CLOUDINESS. LOW-LEVEL FLOW WILL BE OUT OF THE NORTHWEST WITH A
TRAJECTORY OFF THE GREAT LAKES. THE BEST LIFT AND JET DYNAMICS
WILL BE TO THE SOUTHEAST AND THE DOWNSLOPING FLOW SHOULD KEEP
ANY -SHSN CONFINED TO THE HIGHER TERRAIN OF THE FAR NW CWA... NOT
EXPECTING ANY ACCUMULATION. IT WILL BE BRISK WITH MIXING TO 900
HPA SUPPORTING WIND GUSTS TO AROUND 20 KNOTS.

FRIDAY...
STRONG MID-LEVEL HEIGHT RISES SIGNAL THE RETURN TO A MORE
ZONAL FLOW W/SURFACE HIGH-PRESSURE INVOF THE APPALACHIANS.
THE COLUMN WILL DRY OUT ALONG WITH STRONG SUBSIDENCE AND A
SURFACE FLOW OUT OF THE NORTHWEST...SO EXPECTING A DRY DAY.

SATURDAY...
SURFACE RIDGE MOVES OFFSHORE LEADING TO A SOUTHWEST FLOW
ACROSS THE REGION. THE MODELS INDICATE AN OVERRUNNING REGIME
IN ADVANCE OF A WEAK SHORTWAVE OVER THE GREAT LAKES. ATTM...
THE DEEPEST MOISTURE AND BEST DYNAMICS ARE NORTHWEST OF THE
CWA...THEREFORE ANTICIPATING ANOTHER DRY DAY.

LATE WEEKEND INTO EARLY NEXT WEEK...
THE MODELS INDICATE A SLOW COLD FRONTAL PASSAGE DURING THIS
TIME AS THE SURFACE FRONT BECOMES PARALLEL TO THE MID-LEVEL
FLOW. THIS PRESENTS THE BEST CHANCE OF QPF IN THE LONG TERM
BUT IT SHOULD BE FAIRLY LIGHT AS THERE IS NO GMEX CONNECTION.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

MOSTLY VFR CONDITIONS EXPECTED OVERNIGHT. A COLD FRONT WILL MOVE
THROUGH THE AREA OVERNIGHT. AHEAD OF THE COLD FRONT, MOISTURE MAY
GET TRAPPED IN THE LOW LEVELS, LEADING TO SOME LOWER CIGS AND/OR
VSBYS. A TEMPO GROUP HAS BEEN RETAINED FOR A FEW HOURS BEFORE THE
FRONTAL PASSAGE FOR THE SRN NJ TAF SITES.

GUSTY SOUTHERLY WINDS THIS AFTERNOON WILL BEGIN TO LOSE THEIR GUSTS
AROUND SUNSET, BUT WILL REMAIN A STEADY FLOW THROUGH THE NIGHT.
BEHIND THE FRONTAL BOUNDARY, WINDS WILL SWITCH TO WEST/NORTHWEST AND
REMAIN SO THROUGH TUESDAY. ADDITIONAL GUSTS ARE EXPECTED DURING THE
DAY TUESDAY AROUND 20 KNOTS.

OUTLOOK....

TUESDAY NIGHT...VFR CIGS LOWER TO MVFR CONDITION RAIN SOUTH OF PHL
AFTER 06Z/26. LIGHT WNW WIND BECOMING NNE BY DAWN WEDNESDAY AT 5 TO
15 KT.

WEDNESDAY AND WEDNESDAY EVENING...A COASTAL STORM WILL BRING WIDESPREAD
MVFR VARIABLE IFR CEILINGS. REDUCTIONS IN VISIBILITY DUE TO RAIN ALONG
THE COAST (KACY/KMIV), RAIN SNOW MIX EVENTUALLY CHANGING TO ALL SNOW
IN THE DELAWARE RIVER VALLEY (KTTN KPNE KPHL AND KILG) AND MOSTLY
SNOW KABE AND KRDG. IN ADDITION, EXPECT PERSISTENT NORTHERLY OR
NORTHEASTERLY WINDS DURING THE DAY WITH GUSTS 12-25 KT FROM WEST
TO EAST. PRECIPITATION SHOULD END AS SNOW MOST TAF SITES DURING
THE EVENING AND BY MIDNIGHT BE DIMINISHED TO A FEW FLURRIES EXCEPT
POSSIBLY NO SNOW AT KMIV/KACY.

A PLOWABLE...POSSIBLY SLUSHY SNOW ACCUMULATION IS EXPECTED ON ANY
UNTREATED RUNWAYS-PAVEMENTS AT KRDG AND KABE WEDNESDAY.


THANKSGIVING...CONDITIONS SLOWLY RETURN TO VFR AND WINDS SHIFT TO
WESTERLY OR NORTHWEST. THERE COULD BE BRIEF MVFR CONDITIONS IN
SCATTERED SNOW SHOWERS LATER THURSDAY MAINLY JUST N OF KRDG AND
KABE. WINDS MAY GUST TO 25 KT.

FRIDAY...VFR CONDITIONS EXPECTED.

SATURDAY...VFR CONDITIONS EXPECTED.

&&

.MARINE...
A SMALL CRAFT ADVISORY WILL CONTINUE TONIGHT. THE BAY FLAG WILL
END TUESDAY MORNING, AND THE OCEAN FRONT EXTENDED THROUGH THE DAY
TUESDAY DUE TO ELEVATED SEAS.

OUTLOOK...

TUESDAY NIGHT...DIMINISHING NW TO N WIND WITH WINDS AND SEAS BELOW
SCA CRITERIA. WINDS TURN NE BY DAWN.

WEDNESDAY...GALE CONDITIONS POSSIBLE WITH STRONG NORTHERLY OR
NORTHEASTERLY WINDS. A GALE WATCH HAS BEEN ISSUED FOR MOST OF THE
WATERS....STRONGEST WINDS IN THE ATLANTIC WATERS EAST OF DELAWARE.

WEDNESDAY NIGHT...WINDS WILL SLOWLY DIMINISH TO SCA CRITERIA.

THURSDAY...WINDS ARE EXPECTED TO EVENTUALLY FALL BELOW SCA CRITERIA
BUT ATLANTIC SEAS MAY NOT DROP BELOW 5 FT TIL AT NIGHT.

FRIDAY...POSSIBLE SCA COLD AIR ADVECTION WEST TO NORTHWEST FLOW.

SATURDAY...WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THRESHOLDS.

&&

.CLIMATE...
FOR OUR EIGHT CLIMATE SITES, HERE ARE THE RECORD HIGH TEMPERATURES
FOR NOVEMBER 24TH AND THE MOST RECENT YEAR OF OCCURRENCE.

RECORDS HAVE OCCURRED. DETAILS IN THE RER`S.

RECORD HIGHS 11/24:

ACY:  72  SET IN 1999
PHL:  71  SET IN 1979
ILG:  73  SET IN 1979
ABE:  69  SET IN 1931
TTN:  71  SET IN 1979
GED:  75  SET IN 1992
RDG:  69  SET IN 1979
MPO:  64  SET IN 1931

RECORD HIGHEST TEMP SO LATE IN THE SEASON (NOV 24)...JUST IN CASE WE
REACH THIS VALUE.

ACY: 77 12/7/1997
PHL: 73 12/7/1998 AND LAST OF SEVERAL
ILG: 75 12/4/1998
ABE: 72 12/29/1984 AND LAST OF SEVERAL
TTN: 76 12/7/1998 (LATTER OF TWO)
GED: 77 12/1/1991 (SHORTER POR)
RDG: 77 12/29/1984
MPO: 67 11/29/1990

REGARDING THE MIDWEEK COASTAL STORM BRINGING SNOW TO A LARGE
PORTION OF OUR REGION, WE HAVE INCLUDED DAILY SNOWFALL RECORDS
BELOW FOR OUR FOUR PRIMARY CLIMATE SITES THAT HAVE A LONG-STANDING
UNBROKEN PERIOD OF RECORD (POR) WITH RESPECT TO HISTORICAL
SNOWFALL DATA.

DAILY SNOWFALL RECORDS:

NOVEMBER 26TH:               NOVEMBER 27TH:       PERIOD OF RECORD:

ACY: TRACE 1977,1957,1955    1.2 INCHES 1978            1874

PHL: 6.0 INCHES 1898         6.9 INCHES 1949,1938       1872

ILG: 0.1 INCHES 1950         4.5 INCHES 1978            1894

ABE: 1.7 INCHES 1925         7.0 INCHES 1938            1922

OTHER COOPERATIVE SITE SHORTER HISTORICAL RECORD CAN BE FOUND AT
THE NWS MOUNT HOLLY WEBSITE UNDER NOW DATA.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
     WEDNESDAY NIGHT FOR PAZ054-055.
     WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
     WEDNESDAY NIGHT FOR PAZ060>062-101-103-105.
     WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
     WEDNESDAY NIGHT FOR PAZ070-071-102-104-106.
NJ...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
     WEDNESDAY NIGHT FOR NJZ001-007-008.
     WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
     WEDNESDAY NIGHT FOR NJZ009.
     WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
     WEDNESDAY NIGHT FOR NJZ010-015.
DE...NONE.
MD...NONE.
MARINE...GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING
     FOR ANZ431-450>455.
     SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ430-431.

&&

$$
SYNOPSIS...FRANCK
NEAR TERM...ROBERTSON/PO
SHORT TERM...ROBERTSON
LONG TERM...DRAG/FRANCK
AVIATION...DRAG/FRANCK/ROBERTSON/PO
MARINE...DRAG/FRANCK/ROBERTSON/PO
CLIMATE...





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