Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 270543
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1243 AM EST TUE JAN 27 2015

.SYNOPSIS...
DEEP LOW PRESSURE EAST OF NEW JERSEY EARLY THIS MORNING WILL MOVE
NORTHEAST TODAY. THIS HIGH IMPACT SNOWSTORM WILL AFFECT SOUTHERN
NEW ENGLAND AND LONG ISLAND AS WELL AS EXTREME NE PARTS OF NJ.

A HIGH PRESSURE SYSTEM FROM THE WEST IS EXPECTED TO ARRIVE OVER
THE REGION ON WEDNESDAY NIGHT. A CLIPPER TYPE LOW PRESSURE SYSTEM
IS EXPECTED TO FOLLOW WITH ITS COLD FRONT MOVING THROUGH EARLY
FRIDAY. ANOTHER HIGH PRESSURE SYSTEM IS THEN ANTICIPATED FOR
SATURDAY. ANOTHER LOW PRESSURE SYSTEM SHOULD MOVE THROUGH THE
EASTERN UNITED STATES LATE SUNDAY OR EARLY MONDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE EST HAS BEEN ISSUED AT 1230 AM AND HAS INCLUDED SOME LOWERING
OF WSW FLAGS ACROSS PARTS OF THE AREA. SOME OF THE WARNINGS WERE
CONVERTED TO ADVISORIES. THE BLIZZARD WARNING REMAINS AS IT WAS.
SNOWFALL AMOUNTS ACROSS THE BOARD WERE CUT BY A GOOD AMOUNT. A
STRONG BAND OF SNOW IS APPROACHING THE COASTAL NJ AREAS...MOSTLY
NORTH WITH BLIZZARD-LIKE CONDITIONS EXPECTED TO OCCUR THERE OVER
THE NEXT SEVERAL  HOURS. SNOW IN THE WARNING AREAS IS OCCURRING IN
WAVES...BUT A GOOD DEAL OF BLOWING SNOW IS STILL EXPECTED. UPDATED
SNOW TOTALS AND WSW PRODUCT HAVE BEEN ISSUED.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
IT LOOKS LIKE THE SFC LOW WILL REACH ITS DEEPEST POINT SOMETIME
AROUND 12Z TO 15Z TUESDAY MORNING SOMEWHERE SOUTH OF CAPE COD OR
EASTERN LONG ISLAND. SOME WRAP-AROUND BANDS OF HEAVY SNOW WILL
LIKELY BE CONTINUING OVER NRN NJ FOR A WHILE IN THE MORNING BUT WILL
START TO WEAKEN AND/OR MOVE NEWD BY MID-DAY. A FEW MORE INCHES OF
ACCUMULATION ARE EXPECTED IN THE MORNING BUT NOT MUCH ELSE IN THE
AFTERNOON. POPS ON TUES GO FROM CATEGORICAL IN THE MORNING TO NONE
OR SLGT CHC IN THE LATE AFTN...DECREASING FROM SW TO NE AS THE STORM
PULLS AWAY. GUSTY WINDS MAY CAUSE BLOWING SNOW TO CONTINUE EVEN
THOUGH PRECIP HAS ENDED.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE GFS INITIALIZATION LOOKED SLIGHTLY BETTER THAN THE WRF-NMMB. THE
TROF ITSELF LOOKED SLIGHTLY BROADER, NOT AS SHARP, BUT ALREADY WAS
TAKING A SLIGHTLY NEGATIVE TILT. THERMALLY 850MB AND 925MB IT WAS A
MIXTURE OF GFS AND WRF-NMMB.

OVERALL THERE HAS NOT BEEN THAT MUCH OF A CHANGE IN THE LONG TERM
WITH A CLIPPER TYPE SYSTEM FOR THURSDAY NIGHT AND POSSIBLY A
STRONGER SYSTEM LATE SUNDAY INTO MONDAY. IT WILL BE UNSEASONABLY
COLD AND MOST IF NOT ALL OF THE PCPN WILL BE IN THE FORM OF SNOW.

FOR TUESDAY NIGHT EVEN LOOKING AT THE SLOWEST MODELING SOLUTIONS,
THEY BARELY HAVE ANY MEASURABLE IN OUR CWA. THE FASTER CAN
GGEM/UKMET/GFS SNOW IS LONG GONE. WE REMOVED POPS EXCEPT FOR FAR
NERN CWA AND POSSIBLY SOME LAKE EFFECT SNOW SHOWERS MAKING IT INTO
THE POCONOS. WINDS WILL BE DECREASING, BUT WIND CHILL FACTORS WILL
STILL FALL INTO THE SINGLE NUMBERS AND BELOW ZERO NORTHWESTERN
CWA. BECAUSE OF THE FRESH SNOW COVER, WE SIDED WITH THE COLDER
DATASETS, CLOSER TO NAM MOS.

A QUIETER DAY ON WEDNESDAY WITH HIGH PRESSURE NOSING CLOSER TO OUR
AREA. THE PREDICTED LOW LEVEL MOISTURE DOES NOT LOOK THAT IMPRESSIVE
AND SKIES SHOULD BE MOSTLY SUNNY. EVEN SO, WE LIKELY WILL NOT REACH
THE FREEZING MARK IN THE BULK OF OUR CWA.

WEDNESDAY NIGHT WILL BE A VERY COLD NIGHT. HOW COLD WILL DEPEND UPON
HOW QUICKLY CLOUDINESS STARTS MOVING ACROSS FROM THE NEXT CLIPPER
LIKE SYSTEM. WINDS WILL BE LIGHT REGARDLESS. WE ARE COLDER THAN
ALL OF THE GUIDANCE DATASETS WITH MIN TEMPS AND IN REALITY MAY
NOT BE COLD ENOUGH.

DECREASING SUNSHINE AS THURSDAY PROGRESSES. THERE IS GOOD MODELING
CONSENSUS OF MID LEVEL OMEGA AND QVEC CONVERGENCE WITH THIS SYSTEM
ARRIVING BY 00Z. GIVEN THAT THE WAA PHASE LIKES TO SNEAK IN EARLY,
WE KEPT PCPN CHANCES IN FOR LATE IN THE DAY. PTYPE SHOULD BE
PRIMARILY SNOW. SOME MIXING BASED ON FCST 925MB TEMPS ABOVE ZERO
MIGHT OCCUR FAR SE.

THE BULK OF THE CLIPPER PCPN IS EXPECTED TO OCCUR AT NIGHT. ASSUMING
IT DOES NOT ARRIVE IN TIME FOR THE EVENING COMMUTE, ITS APPEARING TO
BE A BORDERLINE ADVISORY CRITERIA TYPE EVENT SNOW. PCPN SHOULD
END BY FRIDAY MORNING WITH A WINDIER DAY IN WAKE OF THE SYSTEM`S
COLD FRONT.

COLDER WEATHER FOR FRIDAY NIGHT AND SATURDAY AS THE NEXT
ARCTIC/CANADIAN AIR MASS MOVES EASTWARD. WE THEN REPEAT THE PROCESS
LATER IN THE WEEKEND AS THE HIGH PRESSURE SYSTEM MOVES OFFSHORE AND
ANOTHER FRONT APPROACHES THE REGION. ANOTHER LOW PRESSURE SYSTEM IS
FORECAST TO FORM ON THE FRONT. THIS ONE COULD TAP GULFMEX MOISTURE
AND THUS BE A SNOWIER SYSTEM.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

**HIGH IMPACT EVENT, ESPECIALLY TONIGHT AND TUESDAY MORNING**

TONIGHT-EARLY TUESDAY...CONDITIONS VARY FROM SITE TO SITE THIS
EVENING AS SCATTERED AREAS OF LIGHT SNOW CONTINUE TO DEVELOP. AS
THE SNOW SPREADS ACROSS THE AREA OVERNIGHT, CONDITIONS WILL
CONTINUE TO DETERIORATE THROUGH THE NIGHT AND IFR CONDITIONS WILL
BECOME THE NORM AT ALL SITES. A PERIOD OF MODERATE TO AT TIMES
HEAVY SNOW IS EXPECTED TO CONTINUE TO DEVELOP AND SPREAD ACROSS
THE AREA THROUGH THE NIGHT, AND PRODUCE SNOWFALL RATES OF ONE TO
TWO INCHES PER HOUR AT TIMES, ESPECIALLY THROUGH NJ AND THE
DELAWARE VALLEY. IFR TO LIFR CIGS AND VSBYS ARE EXPECTED AS THE
SNOW DEVELOPS AND MOVES ACROSS THE AREA. GUSTY NORTH- NORTHEAST
WINDS WILL CONTINUE, WITH GUSTS TO AROUND 25-30 KNOTS AT TIMES. AREAS
OF BLOWING SNOW ARE EXPECTED.

REST OF TUESDAY...AROUND MIDDAY AND INTO THE AFTERNOON, IMPROVEMENT
TO MVFR CONDITIONS ARE EXPECTED WITH SOME CONTINUED LIGHT SNOW
REMAINING ACROSS THE REGION. BLOWING AND DRIFTING SNOW WILL BE
AN ISSUE, THOUGH, AS WINDS BACK MORE TOWARD THE NORTHWEST WITH
CONTINUED GUSTS INTO THE 25 TO 30 KNOT RANGE. SOME LATE-DAY
IMPROVEMENT TO VFR IS EXPECTED, BUT TIMING IS A LITTLE UNCERTAIN.

OUTLOOK...
TUESDAY NIGHT...VFR. GUSTY NORTHWEST WINDS.

WEDNESDAY AND WEDNESDAY NIGHT...PRIMARILY VFR.

THURSDAY INTO FRIDAY MORNING...VFR TO START THURSDAY THEN LIKELY
BECOMING MVFR OR IFR IN SNOW WITH HIGHEST CONFIDENCE NORTHERN
AIRPORTS AND TERMINALS.

FRIDAY AFTERNOON AND EVENING...VFR WITH GUSTY NORTHWEST WINDS.

FRIDAY OVERNIGHT INTO SATURDAY...PRIMARILY VFR.

&&

.MARINE...
STORM AND GALE WARNINGS HAVE BEEN LEFT AS IS. WINDS ARE FCST TO
INCREASE TONIGHT INTO TUESDAY AS LOW PRESSURE OFF THE MID-ATLANTIC
COAST DEEPENS TO AROUND 975 MB BY 1200Z TOMORROW MORNING. WINDS ARE
EXPECTED TO GUST TO NEAR 50 KT NORTH OF CAPE MAY AND 40 TO 45 KT
SOUTH. SEAS WILL BUILD TO 10 TO 12 FT OR HIGHER TONIGHT  WITH THE NE
FETCH. WINDS AND SEAS WILL GRADUALLY SUBSIDE ON TUESDAY BUT CONDS
WILL REMAIN QUITE ROUGH. ALSO...VSBY WILL BE VERY POOR AT TIME
TONIGHT AND TUESDAY MORNING IN BANDS OF HEAVY SNOW.

OUTLOOK...
TUESDAY NIGHT...WE WILL BE TRANSCENDING FROM GALES INTO SMALL CRAFT
ADVISORY CONDITIONS. FREEZING SPRAY.

WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED WITH
FREEZING SPRAY.

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...NO MARINE HEADLINES ARE
ANTICIPATED. SOME FREEZING SPRAY POSSIBLE WEDNESDAY NIGHT.

FRIDAY AND SATURDAY...A SCA SHOULD EVENTUALLY BE NEEDED FRIDAY AS A
NORTHWEST FLOW OF COLD AIR ADVECTION DEVELOPS BEHIND THE DEPARTING
CLIPPER LOW. WE MIGHT COME CLOSE TO GALE FORCE GUSTS FRIDAY NIGHT.
WINDS SHOULD START DECREASING BELOW SMALL CRAFT ADVISORY LEVELS ON
SATURDAY.

&&

.TIDES/COASTAL FLOODING...
COASTAL FLOOD WARNINGS CONTINUE. STORM SURGE TOTALS WILL PROBABLY
BE LESS THAN EARLIER EXPECTED.

&&

.CLIMATE...
RECORD (VULNERABLE) DAILY SNOW FALL FOR OUR LONG TERM CLIMATE
SITES. TUESDAY 1/27.

ACY 4.0 1946
PHL 4.1 1941
ILG 2.9 2004
ABE 8.0 1897

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
     PAZ054-055-061-062-071-103>106.
NJ...WINTER STORM WARNING UNTIL 3 PM EST THIS AFTERNOON FOR NJZ001-
     007>010-015-019-022-025-027.
     COASTAL FLOOD WARNING UNTIL 7 AM EST THIS MORNING FOR
     NJZ012>014-020>027.
     WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
     NJZ016>018-021-023-024.
     BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR NJZ012>014-
     020-026.
DE...COASTAL FLOOD WARNING UNTIL 7 AM EST THIS MORNING FOR
     DEZ002>004.
MD...NONE.
MARINE...STORM WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ450>453.
     GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ430-431-454-
     455.

&&

$$
SYNOPSIS...DRAG/GIGI

NEAR TERM.../

SHORT TERM...AMC

LONG TERM...GIGI

AVIATION...DRAG/GIGI/KLINE/ROBERTSON

MARINE...AMC/DRAG/GIGI

TIDES/COASTAL FLOODING...

CLIMATE...






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