Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 201945
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
245 PM EST THU NOV 20 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE WATERS LATER TODAY. A STRONG HIGH
PRESSURE SYSTEM WILL MOVE IN FROM THE WEST ON FRIDAY, CRESTING
OVER THE REGION ON SATURDAY BEFORE MOVING OFFSHORE ON SUNDAY.
MEANWHILE, LOW PRESSURE WILL DEVELOP ACROSS THE INTER-MOUNTAIN
WEST, AND TRACK NORTHEASTWARD TO LAKE MICHIGAN. THIS LOW WILL
BRING A COLD FRONT THROUGH THE REGION EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE COLD FRONT IS MOVING SLOWLY TOWARDS THE REGION AND WILL MOVE
THROUGH THE AREA LATER TODAY.

DUE TO THE SLOWER MOVEMENT OF THE FRONT, WARMER AIR HAS MADE ITS
WAY INTO THE AREA ON THE SOUTHWESTERLY FLOW. TEMPERATURES WERE
ADJUSTED TO BETTER REFLECT CURRENT OBSERVATIONS AND TRENDS.
SHOULD SEE MAX TEMPS INTO THE MID 50S ACROSS SOUTHERN DELMARVA
AND EXTREME SOUTHERN NEW JERSEY, RANGING TO THE LOWER 40S ACROSS
THE NORTHERN PARTS OF THE FORECAST AREA. THE SOUTHERN POCONOS AND
THE AREAS OF HIGHER TERRAIN WILL REMAIN COOLER, IN THE MID 30S TO
NEAR 40.

WINDS WILL GRADUALLY SHIFT TO A MORE WESTERLY DIRECTION BUT WILL
REMAIN GUSTY THROUGH THIS AFTERNOON AND INTO THIS EVENING. SKIES
HAVE LARGELY CLEARED OUT AND SHOULD BE MOSTLY TO PARTLY SUNNY
THROUGH THE REST OF THE AFTERNOON.

&&

.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 /20Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

AREAS OF MID TO HIGH LEVEL CLOUDS AT 5-10,000 FEET HAVE BECOME
MORE SCATTERED THIS AFTERNOON. ONLY SCATTERED MID-LEVEL CLOUDS ARE
EXPECTED THROUGH FRIDAY. HOWEVER, THE MAIN STORY WILL BE GUSTY
WINDS. SPORADIC GUSTS AROUND 25 KNOTS HAVE OCCURRED THIS AFTERNOON
AND WILL CONTINUE GUSTS IN THE TAFS THROUGH 22Z. THE ENVIRONMENT IS
FAVORABLE AGAIN FRIDAY FOR AFTERNOON WIND GUSTS AROUND 25 KNOTS.
THE WIND DIRECTION WILL BE MORE NORTH OF WEST AROUND 300 COMPARED
TO THE SOUTH FO WEST TODAY AROUND 250/260.

OUTLOOK...

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...
SMALL CRAFT ADVISORY IN EFFECT THROUGH FRIDAY. NEAR GALE GUSTS
POSSIBLE LATER TODAY AFTER THE FROPA AND FRIDAY.

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...MEOLA
SHORT TERM...O`HARA
LONG TERM...KLEIN
AVIATION...GAINES/KLEIN/O`HARA
MARINE...KLEIN/O`HARA





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