Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 242038
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
338 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/...
ANY REMAINING WIND GUSTS SHOULD BEGIN TO TAPER OFF THROUGH THE REST
OF THE AFTERNOON, AND WEAKEN EVERYWHERE AROUND SUNSET. DRY WEATHER
IS EXPECTED OVERNIGHT, EVEN THOUGH A COLD FRONT IS FORECAST TO MOVE
ACROSS THE AREA. ALL GUIDANCE IS INDICATING THE RAIN REMAINING TO
OUR NORTH AND WEST AND DRYING BEFORE IT REACHES OUR AREA. THE DRY
COLD FRONT WILL PROGRESS THROUGH THE AREA OVERNIGHT FROM WEST TO
EAST, WITH THE MAIN EFFECT SOUTHERLY WINDS AND AN INCREASE IN CLOUD
COVER AHEAD OF THE FRONT, WITH PARTIALLY CLEARING SKIES AND WESTERLY
WINDS BEHIND IT.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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 /WEDNESDAY THROUGH MONDAY/...

**WINTER STORM/EVENT OF WET SNOW AT HAND E PA AND NW NJ. WATCHES
 WILL BE EXPANDED TO JUST NW OF THE I-95 INTERSTATE CORRIDOR**

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 210M 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 BE NEAR
OR SLIGHTLY BELOW NORMAL BUT NOT A HARD FREEZE SUBSEQUENT TO THE
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 BY 10 AM WEDNESDAY.

THE WATCH WILL BE EXPANDED SOUTHWARD TO JUST NW OF I-95 IN THE 330 PM.
ANY FURTHER CHANGE AFTER THIS WRITING IS RELATED TO A SUBSTANTIAL
CHANGE IN THE EVENTUAL 12Z ECMWF RECEIPT.

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

WEDNESDAY THROUGH MIDNIGHT WEDNESDAY EVENING...

WEST OF I-95...MAINLY WHERE SOME BANDING AND ASSOCIATED SNOWFALL
RATE ENHANCEMENT 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? FIVE PLUS TOTALS...ESPECIALLY ELEVATIONS WHERE 10
INCHES MAY ACCUMULATE ABOVE 1000 FT (POCONOS AND SUSSEX COUNTY NJ).

I-95 CORRIDOR RAIN MIXING WITH OR CHANGING TO WET SNOW AT TIMES OR
POSSIBLY REMAINING AS SNOW DURING THE AFTERNOON. WHILE QPF IS
GREATER HERE...ACCUMULATION 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 6 INCHES OF WET SNOW WERE TO OCCUR...THE
RISK OF BROKEN TREE LIMBS SHOULD INCREASE CONSIDERABLY BUT ONLY
WHERE 6 INCHES OCCURS. TOTALS UNKNOWN BUT SUSPECT 0.5 TO 4 INCH
AMOUNTS. FINE LINE ON WHERE IT WILL SNOW BUT TOO MUCH INFO ATTM TO
WARRANT A WATCH PER INTERNAL COLLABORATION.

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 THROUGH OUT 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.

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 THE 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 -SHRA 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 /20Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

ALL TAFS HAVE RETURNED TO VFR, AND SHOULD REMAIN SO THROUGH THE
REMAINDER OF THE AFTERNOON INTO THIS EVENING. 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 INSERTED FOR A FEW HOURS BEFORE THE
FRONTAL PASSAGE FROM THE DELAWARE VALLEY TAFS TOWARD THE COASTAL
TAFS, WITH THE LOWEST CONDITIONS EXPECTED CLOSER TO THE COAST.
BEHIND THE FRONT, IMPROVING CONDITIONS ARE EXPECTED AND SHOULD
REMAIN VFR INTO TUESDAY.

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.

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...
THE GALE WARNING HAS BEEN DROPPED AS WINDS HAVE STRUGGLED TO
APPROACH GALE FORCE IN THE SOUTHERLY FLOW. WE WILL CONVERT TO A
SMALL CRAFT ADVISORY, WITH THE BAY ENDING 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.

WEDNESDAY...GALE CONDITIONS POSSIBLE WITH STRONG NORTHERLY OR
NORTHEASTERLY WINDS.

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
SHORT TERM...ROBERTSON
LONG TERM...DRAG/FRANCK
AVIATION...DRAG/FRANCK/ROBERTSON
MARINE...DRAG/FRANCK/ROBERTSON
CLIMATE...STAFF





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