Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 201636
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1136 AM EST THU NOV 20 2014

.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE AREA TODAY. HIGH PRESSURE
SYSTEM WILL BUILD INTO THE AREA TONIGHT THROUGH FRIDAY NIGHT. THE
HIGH WILL MOVE OFFSHORE THIS WEEKEND. LOW PRESSURE WILL TRACK OVER
THE GREAT PLAINS AND UPPER MIDWEST SUNDAY INTO MONDAY. MEANWHILE,
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE MID-ATLANTIC STATES
SUNDAY NIGHT FOLLOWED BY A COLD FRONT MOVING THROUGH EARLY NEXT
WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

11:30 AM UPDATE: UPDATING EARLY TO ACCOUNT FOR SLOWER MOVEMENT OF
THE FRONTAL BOUNDARY INTO THE REGION. AS A RESULT, TEMPERATURES
HAVE BEEN ON THE WARMER END OF WHAT OUR FORECASTING TOOLS SHOW US.
RAISED HOURLY AND MAXIMUM TEMPERATURES A FEW DEGREES ACROSS THE
REGION PER LAV AND HOURLY OBS. SOUNDINGS ALSO SHOW SOUTHERN
DELMARVA LOCATIONS HAVE A SHOT AT MID 50`S FOR HIGHS TODAY. WIND
SHIFT TO WESTERLY WITH GUSTS TO 25 MPH IS STILL OCCURRING BUT MAY BE
LAGGING BY A HOUR OR TWO FROM PREVIOUS UPDATE.

STILL EXPECTING A PRECIPITATION FREE DAY WITH THE DRY AIRMASS
CURRENTLY IN PLACE. HOWEVER, ENOUGH MOISTURE IS PRESENT IN THE
MID-LEVELS TO RESULT IN A MOSTLY CLOUDY PERIOD TODAY.


&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
ANOTHER DRY AND COLD NIGHT EXPECTED ACROSS THE AREA. HIGH PRESSURE
WILL BEGIN TO RIDGE IN FROM THE WEST...AND A DECENT PRESSURE
GRADIENT WILL STILL BE ACROSS THE AREA. WEST TO NORTHWEST WINDS WILL
REMAIN SOMEWHAT GUSTY THIS EVENING AND THEN DECREASE OVERNIGHT. LOW
TEMPERATURES WILL FALL INTO THE LOW TO MID 20S ACROSS THE REGION.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE UPPER TROUGH ASSOCIATED WITH THE RECENT COLD STRETCH WILL MOVE
DOWNSTREAM OFF THE EAST COAST LATE IN THE WEEK. MEANWHILE, SURFACE
HIGH PRESSURE CENTERED OVER THE MIDWEST FRIDAY MORNING WILL BUILD
EASTWARD TOWARD THE MID-ATLANTIC REGION FRIDAY AFTERNOON. THE
LOW-LEVEL THERMAL TROUGH WILL RESIDE OVERHEAD ON FRIDAY, RESULTING
IN THE THIRD WINTER-LIKE DAY THIS WEEK WITH AFTERNOON HIGHS ONLY IN
THE 30S. FORECAST 925 MB TEMPS ABOUT 2C WARMER THAN WITH THE RECENT
COLD SHOT ON TUESDAY-WEDNESDAY WHICH WOULD TRANSLATE TO HIGHS IN THE
MID 30S FOR MOST OF THE AREA (5-10F COLDER IN THE MOUNTAINS). THE
FLOW IN THE BOUNDARY LAYER VEERS OUT OF THE NORTHWEST ON FRIDAY,
WHICH COULD SHIFT ANY RESIDUAL SNOW SHOWERS FROM LAKE ERIE FARTHER
SOUTH TOWARD THE POCONOS. ADDED FLURRIES TO THE FORECAST WITH THE
PROSPECTS OF ACCUMULATING SNOW UNLIKELY.

THE SETUP FOR RADIATIONAL COOLING WILL BE BETTER FRIDAY NIGHT THAN
IN PAST NIGHTS WITH THE CENTER OF THE HIGH OVER THE MID ATLANTIC.
FAVORED THE COLDER MOS GUIDANCE FOR TEMPS IN THIS SITUATION.
FORECAST MIN TEMPS ARE IN THE MID TO UPPER TEENS IN THE RURAL AREAS
AND LOW 20S IN THE URBAN AND COASTAL LOCALES.

SURFACE HIGH PRESSURE WILL MOVE OFFSHORE THIS WEEKEND WHILE A RIDGE
BUILDS ALOFT OVER THE EASTERN CONUS. THE COLD AIR WILL RETREAT AS
SOUTHERLY RETURN FLOW DRAWS WARMER AIR UP THE EASTERN SEABOARD.
HIGHS IN THE 30S IN THE HIGHER ELEVATIONS AND 40S IN THE COASTAL
PLAIN WILL STILL BE BELOW NORMAL ON SATURDAY. STRENGTHENING
SOUTHWESTERLY FLOW ALOFT MAY PRODUCE OVERRUNNING PRECIP IN THE
NORTHERN FRINGE OF THE CWA SATURDAY NIGHT. THERE IS SOME CONCERN FOR
LIGHT FREEZING RAIN IN THE SHELTERED VALLEYS OF NORTHWEST
NJ/NORTHEAST PA WITH LOWS NEAR FREEZING, ALTHOUGH UNCERTAINTY IN
THIS HAPPENING IS VERY HIGH.

A LARGE SCALE TROUGH WILL AMPLIFY OVER THE CENTRAL CONUS SUNDAY INTO
MONDAY, LEAD TO THE DEVELOPMENT OF SURFACE LOW PRESSURE IN THE
SOUTHERN PLAINS. THIS SURFACE LOW IS FORECAST TO TRACK NORTHWARD
INTO THE UPPER MIDWEST BY MONDAY. DOWNSTREAM IMPACTS OF THIS SYSTEM
WILL INCLUDE DEEPENING SOUTHERLY FLOW OVER THE EASTERN CONUS. RAIN
IS FORECAST TO OVERSPREAD THE AREA FROM SOUTH TO NORTH SUNDAY
AFTERNOON INTO SUNDAY NIGHT AS A WARM FRONT MOVES INTO THE AREA.
INCREASED POPS TO 70-80 PERCENT FOR THIS PERIOD WITH THE 00Z
GFS/ECMWF/CMC IN GOOD AGREEMENT WITH TIMING OF PRECIP. WE STILL MAY
SEE A FEW SHOWERS ON MONDAY BUT POPS WERE LOWERED AS THE DRY SLOT
AHEAD OF THE UPSTREAM LOW ADVANCES INTO THE AREA. MONDAY WILL BE THE
WARMEST DAY IN THE PERIOD WITH THE POTENTIAL TO SEE HIGHS WELL INTO
THE 60S.

A COLD FRONT IS FORECAST TO MOVE THROUGH THE REGION SOMETIME EITHER
MONDAY NIGHT OR TUESDAY. WITH THE UPPER TROUGH STILL TO OUR WEST AND
THE FLOW REMAINING SOUTHWESTERLY ACROSS THE EASTERN SEABOARD, THE
CORE OF THE COLD AIR BEHIND THE FRONT SHOULD NOT REACH US BY
MIDWEEK. THEREFORE, TEMPS ARE TRENDING TOWARD NORMAL TUESDAY AND
SLIGHTLY BELOW NORMAL WEDNESDAY.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

VFR CONDITIONS ARE EXPECTED AT THE TERMINALS TODAY AND TONIGHT. THERE
IS SOME MID LEVEL CLOUDINESS WHICH WILL AFFECT THE AREA THIS
MORNING. THIS CLOUDINESS IS ASSOCIATED WITH WEAK WARM AIR ADVECTION
ACROSS THE AREA. THE CLOUDS WILL EXIT TO THE EAST AS A COLD FRONT
CROSSES THE AREA. WINDS...WHICH ARE EITHER VRB OR MOSTLY S/SW OVER
THE AREA EARLY THIS MORNING WILL BECOME WRLY AND A BIT GUSTY LATER
THIS MORNING AND WILL PERSIST INTO THE AFTERNOON. WINDS GUSTS UP TO
20 KTS POSSIBLE.

TONIGHT...VFR WITH MOSTLY CL SKIES AND LIGHT WRLY WINDS.

OUTLOOK...
FRIDAY...NW WINDS WILL GUST TO 20-25 KT. VFR EXPECTED.

FRIDAY NIGHT THROUGH SATURDAY NIGHT...LIGHT SW WINDS DEVELOP. VFR
EXPECTED.

SUNDAY THROUGH MONDAY...MVFR TO POTENTIALLY IFR POSSIBLE, ESPECIALLY
LATE SUNDAY AFTERNOON AND SUNDAY NIGHT AS RAIN MOVES INTO THE AREA.
A FEW SHOWERS MAY LINGER INTO MONDAY BUT CONDITIONS SHOULD IMPROVE
TO VFR BY THE AFTERNOON.

&&

.MARINE...
TOOK THE GALE FLAG DOWN AND RAISED SCA FLAG FOR THE REST OF TODAY
AND INTO FRIDAY. NEAR GALE GUSTS POSSIBLE LATER TODAY AFTER THE
FROPA AND FRIDAY. UPCOMING SHIFT CAN DECIDE ON FUTURE FLAGS.

OUTLOOK...
FRIDAY...HIGH-END SCA CONDITIONS LIKELY FRIDAY MORNING BUT WINDS
RELAX A BIT DURING THE AFTERNOON. STILL CANNOT RULE OUT THE NEED
FOR A GALE WARNING IN THE ATLANTIC WATERS EARLY FRIDAY GIVEN THE
DEEP MIXING PROFILES OVER THE OCEAN.

FRIDAY NIGHT THROUGH SUNDAY...SUB-SCA CONDITIONS, ALTHOUGH WINDS
WILL BE NEAR THRESHOLD FOR A PERIOD SATURDAY NIGHT.

SUNDAY NIGHT AND MONDAY...A STRONG SOUTHERLY JET IS FORECAST TO
DEVELOP JUST OFF THE SURFACE SUNDAY NIGHT. THIS WILL BE ASSOCIATED
WITH A WARM AIRMASS THAT IS MOVING IN, WHICH DOES NOT PROVIDE A
FAVORABLE MIXING SETUP. CURRENTLY ADVERTISING SCA WINDS AND SEAS FOR
THIS PERIOD.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST FRIDAY FOR ANZ430-431-
     450>455.

&&

$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/O`HARA
SHORT TERM...O`HARA
LONG TERM...KLEIN
AVIATION...KLEIN/O`HARA
MARINE...KLEIN/O`HARA






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