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Area Forecast Discussion
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000
FXUS61 KPHI 222350
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
650 PM EST SAT NOV 22 2014

.SYNOPSIS...
STRONG HIGH PRESSURE IS EDGING OFFSHORE. LOW PRESSURE DEVELOPING 
OVER THE CENTRAL PLAINS WILL RAPIDLY INTENSIFY AS IT MOVES INTO THE 
GREAT LAKES SUNDAY NIGHT...DRAWING A STRONG WARM FRONT NORTH THROUGH 
OUR AREA. THE LOW WILL BE NEAR JAMES BAY MONDAY EVENING AS IT SENDS 
A COLD FRONT EASTWARD ACROSS THE EASTERN SEABOARD STATES. HIGH 
PRESSURE FOLLOWS LATER TUESDAY. LOW PRESSURE DEVELOPS OFF THE 
CAROLINA'S WEDNESDAY AND MOVES EAST OF NEW ENGLAND ON THANKSGIVING. 
CANADIAN HIGH PRESSURE HEADS SOUTHEAST INTO THE OHIO VALLEY FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
HIGH PRESSURE WILL CONTINUE TO SHIFT OFF THE MID ATLANTIC COAST 
THROUGH TONIGHT. AS THE FLOW BACKS SOME MORE IN COMBINATION WITH A 
SURFACE HIGH SLIDING TO OUR SOUTHEAST, A LARGE AREA OF WAA WILL 
OCCUR THROUGH TONIGHT. THIS IS MORE NOTED TO OUR WEST AND NORTHWEST 
CLOSER TO THE CORE OF A LOW-LEVEL JET. THIS WILL MAINTAIN SOME 
ISENTROPIC LIFT AS THE WARMING CHIPS AWAY AT THE REMAINING COOLER 
AIRMASS AT THE SURFACE. THIS PROCESS IS LEADING TO AN AREA OF 
CLOUDINESS THAT CONTINUES TO SPREAD EAST ACROSS MUCH OF THE CWA.

THE WAA AND ASSOCIATED LIFT WITH THE AFOREMENTIONED SHORT WAVE HAS 
BEEN GENERATING AN AREA OF LIGHT PRECIPITATION FROM CENTRAL NEW 
YORK/PENNSYLVANIA ON NORTHEASTWARD. SOME OF THIS WILL MOVE ACROSS 
OUR REGION THROUGH THIS EVENING IN THE FORM OF SPRINKLES, HOWEVER
WITH THE MAIN LOW- LEVEL JET PASSING TO OUR NORTH ALONG WITH THE
BETTER LIFT THERE, ANY PRECIPITATION SHOULD BE RATHER LIGHT AND
SPOTTY. THE FORECAST SOUNDINGS CONTINUE TO SHOW A RATHER DRY LAYER
IN THE LOWEST LEVELS AND THIS COMBINED WITH WEAK FORCING RESULTS
VERY LIGHT PRECIPITATION. THERE IS LITTLE MODEL SUPPORT TO BRING
IN MEASURABLE PRECIPITATION, AND THE WPC QPF IS PRETTY MUCH DRY.
TEMPERATURES THROUGH THE EVENING IN THE COLDEST SPOTS LOOK JUST
WARM ENOUGH TO PREVENT ANY FROZEN PRECIPITATION. THE SPS THAT WAS
IN EFFECT FOR TONIGHT WILL BE ALLOWED TO EXPIRE.

DID RAISE LOW TEMPERATURES SOME WITH THE LATEST 6;30 PM UPDATE AS
CLOUD COVER HAS KEPT TEMPERATURES UP ACROSS MOST OF THE REGION.
DOWN IN THE SOUTHERN DELMARVA TEMPERATURES ARE RUNNING SEVERAL
DEGREES COOLER OUTSIDE THE CLOUD SHIELD. 

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
AN UPPER-LEVEL TROUGH IS FORECAST TO BE AMPLIFYING DURING SUNDAY 
ACROSS THE PLAINS. THIS WILL ALLOW SOME RIDGING TO DEVELOP 
DOWNSTREAM, RESULTING IN THE SURFACE HIGH TO BECOME ANCHORED 
OFFSHORE. THIS WILL PROVIDE A SOUTHERLY FLOW AND WITH WAA CONTINUING 
AND EVEN STRENGTHENING SOME DURING THE DAY, A WARMER DAY IS 
ANTICIPATED. 

THE LOCATION OF A LOW-LEVEL JET IN COMBINATION OF SOME SHORT WAVE 
ENERGY AND ISENTROPIC LIFT SHOULD KEEP ANY MORNING LIGHT 
PRECIPITATION FOCUSED TO OUR NORTH. MEANWHILE, A WARM FRONT WILL 
CONTINUE TO ORGANIZE TO OUR SOUTH AS LOW PRESSURE CONSOLIDATES IN 
THE VICINITY OF THE TENNESSEE VALLEY BY LATE IN THE DAY. WHILE THERE 
WILL BE SOME CLOUDS AROUND, SOME THINNING SHOULD OCCUR FOR A TIME 
BEFORE AN INCREASE DEVELOPS AGAIN TOWARD EVENING. IT APPEARS THAT 
ANY ORGANIZED LIFT REMAINS AWAY FROM OUR AREA, THEREFORE WE WILL 
CARRY A DRY FORECAST DURING THE DAYLIGHT HOURS.

AS FOR HIGH TEMPERATURES, A GFS/NAM MOS BLEND WAS GENERALLY USED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
**RECORD WARMTH MONDAY FOLLOWED BY A POTENTIAL WINTER STORM/EVENT
 FOR PORTIONS OF OUR AREA WEDNESDAY**

ANOTHER HIGH AMPLITUDE TROUGH NEAR 100W LONGITUDE TO START SUNDAY
NIGHT LIFTS NEWD INTO QUEBEC BY TUESDAY WITH A NEW TROUGH EVOLVING
OVER THE EASTERN USA WEDNESDAY BUT FULL OF UNCERTAINTY REGARDING
THE SHORT WAVE INTERACTIONS - AMPLITUDE AND TRANSLATION SPEEDS. SO
WHILE A MID ATLANTIC COASTAL WINTER EVENT IS FORECAST, IT IS NOT
YET A LOCK DUE TO THE PREVIOUSLY MENTIONED UNCERTAINTY. A GENERAL
CYCLONIC FLOW AT MID LEVELS CONTINUES OVER THE NORTHEAST USA THURSDAY
INTO THE WEEKEND WITH UNCERTAINTY REGARDING THE EMBEDDED SHORT WAVES.
 
TEMPERATURES: CALENDAR DAY AVERAGES HAVE BEEN BELOW NORMAL SINCE THE 
13TH (9 CONSECUTIVE DAYS).  MODELS AGREE ON TEMPS ABOUT 15 TO 20 
DEGREES ABOVE NORMAL MONDAY...MAYBE 5 DEGREES ABOVE NORMAL TUESDAY...
BELOW NORMAL WED-FRI AND 5 TO 10 DEGREES BELOW NORMAL SATURDAY.

FORECAST BASIS: UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS 
FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 12Z/22 NAM/GFS 
MOS FOR THE PERIOD SUNDAY NIGHT-MONDAY NIGHT. THEN THE 12Z/22 GFS
MOS IS APPLIED TUESDAY AND TUESDAY NIGHT. THEREAFTER (WEDNESDAY
ONWARD) THE 1522Z/22 WPC GRIDDED GUIDANCE WHICH AT TIMES IS BLENDED
50 50 WITH THE 12Z/22 GFS MEXMOS. ALL THIS IS EVENTUALLY CHECKED
AGAINST THE 12Z/22 ECMWF TO SEE IF WE'RE IN THE BALLPARK WITH
ECMWF CYCLICALLY PERSISTENT 18Z 2 METER TEMPERATURES. PRECIPITATION
PROBABILITY GUIDANCE IS CHECKED AGAINST THE 09Z/22 SREF 3HRLY POPS
FOR .01 THROUGH 00Z WEDNESDAY AND THEREAFTER THE 12Z/22 GEFS 6HR
POPS FOR 0.05.

THE DAILIES...

SUNDAY NIGHT...WAA WITH PERIODS OF SHOWERY RAINS...MAINLY AFTER
MIDNIGHT AND POSSIBLY HEAVY FOR A TIME. AN ISOLATED SVR TSTM IS
NOT IMPOSSIBLE IN DEL/NJ WITH SWI -1, TT 48, KI 32 AND 60-70KT
WIND AT 850 MB ON THE ECMWF IN THE 3AM-6 AM (08Z-11Z) TIME FRAME. 
12Z NAM HAS SIMILAR ELEVATED INSTABILITY AT 09Z MONDAY. 12Z GFS
LEAST ROBUST OF THE THREE 12Z MODELS MENTIONED. GRIDS HAVE THE CHC
TSTM IN SNJ AND THE DELMARVA EARLY MONDAY MORNING.

MONDAY...BECOMING PARTLY SUNNY...WINDY AND WARM (AFTER EARLY
MORNING SHOWERS RACE NE AT 50 KTS (NEAR 60 MPH). RECORD WARMTH
EXPECTED AND SOUTHWEST WIND GUSTS OF 35-40 MPH. BLENDED TRANSPORT
WIND SUPPORTS 40 MPH GUSTS IN THE AFTERNOON...POSSIBLY 45.

MONDAY NIGHT...PARTLY CLOUDY WITH MAYBE A LOW TOPPED SPRINKLE OR
SHOWER ACCOMPANYING THE COLD FRONT PRIOR TO MIDNIGHT.

TUESDAY...PARTLY TO MOSTLY SUNNY (MOSTLY CIRRUS)...BREEZY AND
STILL WITH TEMPS ABOUT 5 DEGREES ABOVE NORMAL. 

WEDNESDAY...A COASTAL STORM IS LIKELY. THE OPERATIONAL ECMWF IS
PRETTY STABLE THESE PAST TWO CYCLES AND HAS BEEN CONSISTENTLY
FURTHEST WEST WITH THIS OPPORTUNITY FOR PCPN THE PAST SEVERAL
DAYS. THE 12Z GFS HAS MOVED WEST WITH THE TRACK. NO LOCK ON THE
TRACK SINCE SHORT WAVE INTERACTIONS SHOW VARIABILITY IN THE
ENSEMBLES. STILL...IT LOOKS AS IF THE BOUNDARY LAYER TEMP IS GOING
TO GOVERN WHERE ITS MOSTLY SNOW. DAYTIME TEMPS 5 TO 10 DEGREES
BELOW NORMAL.

ADVISE ALL WITH TRAVEL PLANS WEDNESDAY AFTERNOON AND NIGHT IN OUR
FORECAST AREA TO CLOSELY MONITOR FUTURE FORECASTS. THIS COULD BECOME
A SNOW STORM FOR PORTIONS OF OUR FORECAST AREA WITH PLOWABLE SNOW
AND NEAR FREEZING TEMPERATURES....ESPECIALLY THE INTERSTATE 95 CORRIDOR.

THAT WOULD MEAN A SIGNIFICANT IMPACT DUE TO HOLIDAY TRAVEL AND ONE
OF THE BUSIEST AIR TRAVEL DAYS OF THE YEAR. 

IF THIS FORECAST REMAINS SIMILAR SUNDAY...BRIEFING PACKAGES WOULD
BEGIN SUNDAY AFTERNOON AROUND 330 PM. 

THURSDAY INTO FRIDAY MORNING...CONSIDERABLE CLOUDINESS WITH A CHANCE
OF SNOW SHOWERS OR FLURRIES AS THE PRIME TROUGH SHIFTS ACROSS THE AREA.

FRIDAY-SATURDAY...WPC GUIDANCE WITH COLDER THAN NORMAL TEMPS AS A
LOW LVL WNW FLOW APPEARS TO PREVAIL WITH CANADIAN HIGH PRESSURE
HEADING ESEWD THROUGH THE OHIO VALLEY TO THE MID ATLANTIC STATES.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

REST OF THIS AFTERNOON...VFR CEILINGS AT OR ABOVE 5,000 FEET FOR 
MOST TERMINALS. A FEW SPRINKLES WILL BE AROUND MAINLY FROM 
NEAR THE KPHL METRO ON NORTH AND WESTWARD. SOUTHWESTERLY WINDS 
AROUND 10 KNOTS WITH SOME LOCAL GUSTS UP TO 20 KNOTS.

TONIGHT...VFR, WITH AREAS OF CEILINGS AT OR ABOVE 5,000 FEET.  
SOUTHWESTERLY WINDS DIMINISHING TO 5 KNOTS OR LESS.

SUNDAY...VFR, WITH CEILINGS AT TIMES ABOVE 5,000 FEET. SOUTHWEST 
WINDS 5-8 KNOTS, BECOMING SOUTHEAST LATE.

OUTLOOK...
LATER SUNDAY NIGHT THROUGH 12Z MON...VERY POOR FLYING CONDS WITH
MVFR EXPECTED AND IFR PSBL IF NOT PROBABLE IN PERIODS OF SHOWERY
RAINS. RAIN COULD BE HVY AT TIMES WITH A POSSIBLE TSTM AFTER 06Z/24
SUNDAY NIGHT. E TO SE WIND COULD GUST IN THE 25 TO 30 KT RANGE
TOWARD 09Z MONDAY. LLWS POTENTIAL AT KACY NEAR 09Z MONDAY. HIGH
CONFIDENCE.

MONDAY AND MONDAY NIGHT...IMPROVING TO VFR SCT-BKN AOA 3500 FT 
(AFTER ANY LINGERING SHOWERS RAPIDLY DEPART NEWD BY 14Z). SW WIND
GUST 30-38 KT. CFP/SHIFT MON EVE WITH A POSSIBLE BRIEF SHOWER OR
SPRINKLE...ESPECIALLY E PA. MDT CONFIDENCE.

WEDNESDAY...MUCH UNCERTAINTY DEPENDING ON THE TRACK OF A COASTAL 
LOW. COULD BE VFR IF LOW IS FAR ENOUGH EAST OR MVFR/IFR IN RAIN/SNOW 
AND WIND IF LOW IS FAR ENOUGH W. AS IT STANDS WITH TODAYS MODEL AND
NCEP COLLABORATED GUIDANCE...PLAN ON PRECIPITATION CHANGING TO SOME
SNOW AND A PERIOD OF IFR CONDITIONS. CONFIDENCE LOW TO MODERATE.

THURSDAY...VFR CIGS WITH A POSSIBLE BRIEF PERIOD OF MVFR CONDS IN
SCT SNOW SHOWERS OR FLURRIES.

&&

.MARINE...
A SOUTHWESTERLY FLOW WILL OCCUR THROUGH SUNDAY AS STRONG HIGH 
PRESSURE SHIFTS OFFSHORE AND INTO THE WESTERN ATLANTIC. AS THIS 
OCCURS, THE PRESSURE GRADIENT IS FORECAST TO TIGHTEN SOME THROUGH 
MUCH OF TONIGHT. A LOW-LEVEL JET IS FORECAST TO TRACK MAINLY TO OUR 
NORTH, HOWEVER THE 925 MB WINDS INCREASE TO NEAR 30 KNOTS TONIGHT. 
THE FORECAST SOUNDINGS INDICATE SOME MIXING OCCURS, ALTHOUGH SURFACE 
GUSTS MAY BE MARGINAL. THE SOUTHWESTERLY FLOW SHOULD ALSO BUILD THE 
SEAS, HOWEVER THE STRONGEST WINDS AND HIGHEST SEAS MAY SETUP TO OUR 
NORTHEAST. SINCE THERE IS STILL POTENTIAL, WE WILL MAINTAIN THE 
SMALL CRAFT ADVISORY THROUGH 11Z SUNDAY FOR ALL BUT THE DELAWARE 
BAY. THE CONDITIONS SHOULD GENERALLY BE BELOW ADVISORY CRITERIA 
SUNDAY.

OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY...GALE WATCH HAS BEEN ISSUED WITH 
STRONGEST INFLOW SE WINDS OF POTENTIAL 35-40 KT GUSTS NEAR DAWN
MONDAY. WINDS SHIFT SW IN THE WARM SECTOR AND MAY GUST 35 KT ALONG
THE COAST WHERE NEAR RECORD WARMTH PREVAILS.

BLENDED 12Z/22 NAM/GFS TRANSPORT WIND SUPPORTS GALE GUSTS 06Z MONDAY-
02Z TUESDAY. FOR NOW THE GALE WATCH ENDS AT 22Z MONDAY.

MONDAY NIGHT INTO TUESDAY....A COLD FRONTAL PASSAGE AND SCA CONDS AS SEAS 
AND WIND EVENTUALLY SUBSIDE LATE TUESDAY.

WEDNESDAY-THURSDAY...PLAN ON SCA CONDITIONS REDEVELOPING AS A COASTAL
LOW DEVELOPS. SMALL POTENTIAL FOR A GALE LATE WEDNESDAY.

&&

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

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

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY AFTERNOON FOR 
     ANZ430-431-450>455.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...DRAG
NEAR TERM...GAINES/GORSE
SHORT TERM...GORSE
LONG TERM...DRAG
AVIATION...DRAG/GORSE
MARINE...DRAG/GORSE
CLIMATE...






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