Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 222102
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
402 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
CAROLINAS 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 NORTHWESTERN ZONES THROUGH THIS EVENING, 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. SINCE THIS LOOKS LIKE A RATHER
LOW CHC POTENTIAL OF SPOTTY LIGHT FREEZING RAIN AND WITH LOW
CONFIDENCE, WE WILL HOLD OFF ON AN ADVISORY AND GO WITH A SPECIAL
WEATHER STATEMENT ATTM. FARTHER SOUTHEAST FOR A TIME, A FEW
SPRINKLES COULD OCCUR THROUGH ABOUT MID EVENING.

AS FOR LOW TEMPERATURES, WE USED AN EVEN NAM/GFS MOS BLEND AND THEN
MADE SOME MINOR TWEAKS. THESE COULD BE TRICKY GIVEN THE LOW DEW
POINTS. HOWEVER THE COMBINATION OF SOME CLOUDS, A LIGHT SOUTHERLY
WIND AND A MODERATING AIRMASS IS EXPECTED TO RESULT IN TEMPERATURES
NOT AS COLD AS LAST NIGHT. THE LAMP/LAV GUIDANCE WAS USED TO HELP
WITH TEMPERATURE AND DEW POINT TRENDS THROUGH THIS EVENING.

&&

.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 MONDAY-TUESDAY. THEN THE 12Z/22 GFS MOS IS
APPLIED TUESDAY NIGHT AND WEDNESDAY. THEREAFTER (WEDNESDAY NIGHT
ONWARD) THE 1523Z/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 (SEEMS LIKE A RECENT
WARM BIAS IN THOSE EC 2M TEMPS). 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 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 AND 6 AM TIME FRAME. 12Z NAM HAS
SIMILAR ELEVATED INSTABILITY AT 09Z MONDAY. 12Z GFS LEAST ROBUST
OF THE 3 12Z MODELS MENTIONED. GRIDS HAVE THE CHC TSTM IN SNJ AND
THE 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...BREEZY AND STILL WITH TEMPS
ABOUT 5 DEGREES ABOVE NORMAL. (MOSTLY CIRRUS)

WEDNESDAY...A COASTAL STORM IS LIKELY. THE 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
NW FLOW APPEARS TO PREVAIL WITH CANADIAN HIGH PRESSURE HEADING
ESEWD THROUGH THE OHIO VALLEY TO THE MID ATLANTIC STATES.

&&

.AVIATION /20Z SATURDAY 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 20 TO 305 KT RANGE.
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 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 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  402
NEAR TERM...GORSE 402
SHORT TERM...GORSE 402
LONG TERM...DRAG 402
AVIATION...DRAG/GORSE 402
MARINE...DRAG/GORSE 402
CLIMATE...





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