Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 182321
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
621 PM EST THU DEC 18 2014

.SYNOPSIS...
LOW PRESSURE OVER ATLANTIC CANADA WILL TRACK TO THE NORTHEAST.
HIGH PRESSURE OVER THE NORTHERN GREAT LAKES WILL MOVE INTO THE OHIO
VALLEY OVERNIGHT. LOW PRESSURE IS EXPECTED TO FORM OVER THE GULF
STATES FRIDAY NIGHT AND TRACK ACROSS GEORGIA SATURDAY. A COLD
FRONT MAY MOVE THROUGH THE EASTERN SEABOARD ON CHRISTMAS EVE.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
NO BIG CHANGES WILL BE MADE WITH THIS ESTF. IN ADDITION TO THE
STUBBORN STRATOCU, THERE WILL BE SOME MID LEVEL CLOUDINESS
ASSOCIATED WITH A SHORT WAVE PASS ACROSS OUR CWA TONIGHT WHICH
LOWERS THE CONFIDENCE ABOUT MIN TEMPS. SO FAR SO GOOD AS TEMPS AND
DEW POINTS ARE CLOSE TO PREDICTED VALUES.


CYCLONIC FLOW BTWN THE DEPARTING LOW OVR P.E.I. AND HIGH OVER
LAKE SUPERIOR IS CAUSING ABUNDANT LO LVL MOISTURE TO BE BROUGHT
INTO THE NERN U.S. AND W/ THIS CLD CVR ACROSS ERN PA/NJ-AWAY FM
THE SHORE. PRES GRAD IN PLACE IS CAUSING WINDS TO GUST INTO THE
M20S.

1026 SFC HIGH HAS MOVED INTO MI. CUTOFF LOW WL BE MOVG OVR NOVA
SCOTIA TNGT. XPCTG WNWRLY WINDS TO WEAKEN. LOWS TNGT RANGING FM
THE M20S IN THE POCONOS TO THE L30S NEAR WILDWOOD.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
FRIDAY SHOULD BE DOMINATED BY GREAT LAKES HIGH PRESSURE WHICH
SHOULD YIELD PARTY CLOUDY SKIES.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
MID-LEVEL FLOW THE NEXT COUPLE OF DAYS IS RATHER FLAT THOUGH A
CHANGE TO THAT PATTERN APPEARS LIKELY BY THE END OF THE WEEKEND. A
DEEP TROUGH EMERGES ACROSS THE CENTRAL U.S. BY TUESDAY AS MULTIPLE
PACIFIC NORTHWEST WAVES ROUND THE BASE OF THE TROUGH AND ACROSS OUR
REGION...WE ARE HEADING FOR A VERY UNSETTLED PERIOD BY EARLY NEXT
WEEK.

FRIDAY NIGHT - SATURDAY...LOOKS DRY. FRIDAY SHOULD BE DOMINATED BY
GREAT LAKES HIGH PRESSURE WHICH SHOULD YIELD PARTY CLOUDY SKIES.

SATURDAY NIGHT AND SUNDAY...AN INVERTED TROUGH MAY THROW BACK SOME
MOISTURE ACROSS THE  AREA AS A WEAK WAVE OF LOW PRESSURE MOVES WELL
OFFSHORE OF OUR REGION. ONLY HAVE SLIGHT CHANCE POPS ACROSS THE
NORTHEASTERN PORTION OF THE CWA AS THAT LOOKS LIKE THE MOST
FAVORABLE LOCATION FOR THE TONGUE TO MOISTURE TO REACH. GIVEN THE
OVERNIGHT TIMING PRECIP COULD FALL AS RAIN SNOW MIX OR ALL SNOW.

MONDAY - TUESDAY...LOW PRESSURE MOVES OFF THE CAROLINA COAST AND OUT
TO SEA ON TUESDAY. THIS LOW WILL HELP LIFT A WARM FRONT ASSOCIATED
WITH A LARGE AND DEVELOPING LOW PRESSURE SYSTEM OVER THE MIDDLE OF
THE CONUS INTO THE AREA. ONSHORE FLOW AHEAD OF THE SYSTEM AND WARM
AIR MOVING IN WITH THE FRONT WILL ALLOW FOR A WARMING LOW-LEVEL
THERMAL PROFILE SO PRECIP SHOULD BE PRIMARILY LIQUID. MID-RANGE
CHANCE POPS WILL PERSIST MONDAY...MONDAY NIGHT...AND TUESDAY.

WEDNESDAY...STILL WATCHING A LARGE LOW PRESSURE FORM TO OUR WEST AND
TRACK INTO THE GREAT LAKES REGION ON WEDNESDAY. THIS WOULD KEEP OUR
REGION UNDER A WARMING THERMAL PROFILE WITH A LOT OF MOISTURE TO
WORK WITH. WHAT IS INTERESTING WITH THE LATEST MODEL RUNS IS HOW
THEY ARE SEEMINGLY WEAKENING THE PRIMARY LOW AS IT MOVES INTO THE
LAKES ALLOWING FOR ANOTHER, STRONGER, PIECE OF PAC NW ENERGY TO
PRODUCE CYCLOGENESIS ACROSS THE MID-ATLANTIC. IT APPEARS THAT CHRISTMAS
EVE WL BE A DAY W/ MOISTURE, WINDS, AND POSSIBLY CONVECTION. LKLY
POPS ARE IN THE FCST.

THURSDAY...CHRISTMAS DAY - DEEP LAYER ZONAL FLOW WILL FILL IN
ACROSS THE AREA. DRY CONDITIONS XPCTD AS THE COLD FRONT SHOULD BE
E OF THE AREA. A DEEP STACKED LOW WILL BE OVER THE EASTERN GREAT
LAKES. RIGHT NOW "COOL AND BRZY" COULD BE THE WX WORDS FOR THE DAY.

&&

.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

00Z TAFS WILL BE VFR.

TONIGHT...A VFR CIG IS FORECAST. FOR KACY AND KMIV THIS IS MAINLY
DUE TO MID LEVEL CLOUDS. AT THE KPHL AIRPORTS, ITS A COMBINATION
OF A STRATOCU CIG AROUND 4K AND THE MID LEVEL CLOUD DECK. AT KRDG
AND KABE ITS MAINLY A STRATOCU DECK AT AROUND 3500 FEET. THERE
WILL BE MVFR CIGS AT AIRPORTS FARTHER TO THE NORTHWEST AND MIGHT
MAKE IT INTO THESE LATTER TERMINALS. WEST TO NORTHWEST WINDS
SHOULD AVERAGE LESS THAN 10 KNOTS.

FRIDAY...GOING MORE PESSIMISTICALLY WITH VFR CIGS AND EXPECTING A
STRATOCU CIG TO EITHER PERSIST NORTHWEST TO TERMINALS, OR DEVELOP
ELSEWHERE DURING THE DAY. MVFR CIGS POSSIBLE HIER TERRAIN
AIRPORTS. NORTHWEST WINDS SHOULD BE SLIGHTLY LESS THAN TODAY WITH
SUSTAINED SPEEDS AROUND 10 KNOTS AND PEAK GUSTS CLOSER TO 20
KNOTS. LATE IN THE DAY WE ARE PREDICTING THE GUSTS AND VFR CIGS
SHOULD NO LONGER OCCUR.

OUTLOOK...
FRIDAY NIGHT - SATURDAY...VFR. NORTHWEST WINDS VEER TOWARDS THE
NORTH-NORTHEAST BY SATURDAY.

SUNDAY - MONDAY...SUB-VFR POSSIBLE WITH SCATTERED RAIN/SNOW SHOWERS.

TUESDAY...VFR.

&&

.MARINE...
THE SMALL CRAFT ADVISORY NORTHERN WATERS WILL BE EXTENDED DEEPER
INTO THIS EVENING AS MORE FREQUENT GUSTS TO 25 KTS ARE POSSIBLE,
THE REST OF THE SMALL CRAFT ADVISORY WILL BE DROPPED.

GUSTS NEAR OR ABOVE 20 KT WILL BE POSSIBLE THROUGH THE OVERNIGHT
HOURS ELSEWHERE.

OUTLOOK...
FRIDAY...MOSTLY SUB-ADVISORY CONDITIONS ARE EXPECTED. SOME NORTHWEST
WIND GUSTS COULD STILL BE IN THE 20 PLUS KNOT RANGE, THOUGH.
CONFIDENCE: ABOVE AVERAGE.

SATURDAY - SUNDAY...SUB-SCA EXPECTED FOR THE MOST PART. SEAS REMAIN
AROUND 3 TO 4 FEET.  CONFIDENCE: AVERAGE TO SLIGHTLY BELOW AVERAGE.

MONDAY - TUESDAY...SCA CONDITIONS SHOULD PRESENT THEMSELVES LATER
ON MONDAY UNDER A STRENGTHENING EASTERLY FLOW AND BUILDING SEAS.
CONFIDENCE: AVERAGE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ450-
     451.

&&

$$
SYNOPSIS...GIGI/99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...GIGI/99
MARINE...GIGI/99





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