Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 160932
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
432 AM EST TUE DEC 16 2014

.SYNOPSIS...
LOW PRESSURE IN THE GREAT LAKES WILL PUSH A WARM FRONT NORTH INTO
THE MID ATLANTIC STATES TODAY, WITH SECONDARY LOW PRESSURE DEVELOPING
NEAR LONG ISLAND TUESDAY NIGHT. THE COLD FRONT PASSES OFFSHORE
WEDNESDAY MORNING AS THE LOWS COMBINE AND HEAD FOR THE CANADIAN
MARITIMES THURSDAY. HIGH PRESSURE IN THE GREAT LAKES ASSERTS CONTROL
HERE ON FRIDAY. LOW PRESSURE IN GEORGIA SATURDAY MORNING IS FORECAST
TO INTENSIFY AS IT MOVES NORTHEASTWARD OFF THE MID ATLANTIC COAST
SUNDAY INTO MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS THE VERTICALLY STACKED LOW LIFTS INTO THE GREAT LAKES REGION,
SHOULD SEE A WARM FRONT LIFT THROUGH THE REGION, AND CONSEQUENTLY,
INCREASING MOISTURE AS WELL AS RAIN CHANCES. SINCE THE REGION IS IN
THE WARM SECTOR ALL DAY, PRECIP IS EXPECTED TO BE ALL RAIN. IN
ADDITION, NAM MODEL SOUNDINGS ACROSS SOUTHERN DELMARVA DEPICT MEAGER
ELEVATED INSTABILITY. THEREFORE, A RUMBLE OF THUNDER IS NOT OUT OF
THE QUESTION, BUT SEEMS QUITE UNLIKELY, SO HAVE ONLY MENTIONED RAIN
SHOWERS FOR NOW.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
INITIAL COLD FRONT AND DRY SLOT WILL BE ON OUR DOORSTEP BY 00Z.
SHOULD SEE PRECIP CLEAR OUT QUICKLY ONCE THE DRY SLOT MOVES OVER.
THE ONE EXCEPTION IS IN THE POCONOS, WHICH WILL BE CLOSER TO A
SECOND SHORT WAVE TROUGH PASSAGE LATE TONIGHT, AND WILL ALSO HAVE
ENHANCEMENT WITH OROGRAPHIC LIFT. THEREFORE, THAT REGION COULD SEE
LIGHT PRECIP CONTINUE THROUGH THE OVERNIGHT HOURS. DESPITE AN
INITIAL COLD FRONTAL PASSAGE, TEMPERATURES, EVEN IN THE POCONOS
SHOULD BE HIGH ENOUGH TO SUPPORT RAIN.

MINS WERE A BLEND OF MAV AND MET. HOWEVER, IF THE CLOUDS CLEAR OUT
QUICKER THAN EXPECTED COULD SEE RADIATIONAL COOLING CONTRIBUTE TO
LOWER THAN FORECAST MINS.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
RATHER BENIGN PATTERN SETTING UP FROM THURSDAY THROUGH SATURDAY WITH
ZONAL-ISH FLOW ALOFT TURNING INTO WEAK RIDGING OVER THE WEEKEND. DEEPER
MID-WEST TROUGH LOOKS TO FORM BY EARLY NEXT WEEK WHICH MAY BRING A
SOMEWHAT UNSETTLED PATTERN TO THE REGION. A SYSTEM DOES DEVELOP ALONG
THE TEXAS COAST AND MOVES INTO THE ATLANTIC BY SUNDAY. FROM THIS
POINT ONWARD LOTS OF UNCERTAINTY REMAINS WITH THE TRACK AND
INTENSITY OF THE SYSTEM.

WEDNESDAY...SECONDARY SHORTWAVE ALOFT COULD TOUCH OFF A FEW STRAY
SHOWERS ACROSS THE NORTHERN FRINGE OF THE CWA DURING THE AFTERNOON
HOURS. SOME WEAK MID-LEVEL LAPSE RATES, AS THE SHORTWAVE IS RATHER
ELONGATED ZONALLY, WOULD ADD TO THE CHANCES OF SHOWERS, MOSTLY
LIQUID AT THIS POINT WITH A WARM THERMAL PROFILES. A CHANGEOVER TO
SNOW SHOWERS LOOKS LIKELY BUT THE AMOUNT OF MOISTURE BECOMES AN
ISSUE LATER IN THE EVENING/OVERNIGHT. GUSTY NORTHWEST WINDS
EXPECTED. THERE DOESN`T APPEAR TO BE MUCH ICE LEFT IN THE CLOUDS AT
THIS POINT, AND OUTSIDE ANY SEEDER-FEEDER HELP, WE COULD SEE SPOTTY
FREEZING DRIZZLE OVERNIGHT.

THURSDAY - FRIDAY...DRYING TREND CONTINUES WITH ZONAL-ISH FLOW ALOFT
FORMING BY FRIDAY AND NOT MUCH MOISTURE TO WORK WITH. INSTABILITY
ALOFT CONTINUES TO LOOK ROBUST ON THURSDAY AS THE CENTER OF
MID-LEVEL LOW PASSES OVERHEAD SO THERE COULD BE SOME INSTABILITY
SNOW SHOWERS ACROSS THE NORTH. FRIDAY LOOKS DRY. GUSTY NORTHWEST
WINDS BOTH DAYS THOUGH A DECREASE IS EXPECTED LATER ON FRIDAY.

SATURDAY - SUNDAY...ONE LAST DAY, OR AT LEAST HALF DAY, OF
TRANQUILITY ON SATURDAY BEFORE EAST COAST STORM NEARS FROM THE
SOUTH-SOUTHWEST. DEPENDING ON THE QUICKNESS AND POSITION OF THE
NORTHERN STREAM ENERGY, HELPING TO DEVELOP GULF COAST SURFACE
INFLECTION, DICTATES HOW FAST PRECIPITATION OVERSPREADS FROM THE
SOUTH LATER ON SATURDAY. GUIDANCE ACROSS THE BOARD IS STILL SHOWING
MULTIPLE OUTCOMES AND DEPTHS WITH THIS SYSTEM. THE PAST FEW DAYS OF
RUNS THE OP-EC HAS BEEN HOLDING STEADY WITH A CLOSER TO THE COAST
SYSTEM BUT NOW WE ARE STARTING TO SEE MORE OF AN OFFSHORE AND
WEAKENING TREND WITH A MUCH SLOWER NORTHERLY PROGRESSION. THE EC/GEFS
ENSEMBLES TOO HAVE BEGUN TO WAVER A BIT WITH MOST OF THE NOISE ON
THE NORTHEAST SIDE OF THE MODELED LOWS CENTER WHICH MEANS A FARTHER
EASTWARD JOG IS POSSIBLE. IT IS STILL TOO EARLY TO GO INTO TOO MUCH
DEPTH WITH THIS SYSTEM GIVEN THE AMOUNT OF SPREAD THAT WE ARE STILL
SEEING. ONE THING THAT SHOWS AVERAGE CONFIDENCE ARE THE CHANCES FOR
AN EAST STORM TO IMPACT OUR REGION SOMETIME LATER THIS WEEKEND.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

WIDESPREAD MVFR CONDITIONS, BOTH FOR VISIBILITIES AND CEILINGS, ARE
LIKELY AT ALL TAF SITES FOR MOST OF THE DAY TODAY. COULD ALSO SEE
LOCALIZED IFR CONDITIONS, ESPECIALLY DURING THE PEAK TIME OF THE
-SHRA (GENERALLY BETWEEN 20 AND 00Z). AFTER 00Z, SHOULD SEE DRIER
AIR MOVE INTO THE REGION FROM SW TO NE. AS IT DOES SO, SHOULD SEE
LOW CLOUDS ERODE, BUT BR MAY REMAIN LIMITING VISIBILITIES TO LESS
THAN 6SM.

WINDS WILL SHIFT FROM MOSTLY SOUTHERLY THROUGH THE DAY TO MORE
WESTERLY BY THIS EVENING, BUT SHOULD GENERALLY BE NEAR OR BELOW 10KT.

WEDNESDAY...MOSTLY VFR. WEST WINDS 10-15KT WITH GUSTS 20-25KT. COULD
BE SOME LINGERING MVFR ACROSS THE NORTHERN TERMINALS.

THURSDAY...VFR. NORTHWEST WINDS 10-15KT WITH GUSTS 20-25KT.

FRIDAY - SATURDAY...VFR.

&&

.MARINE...
WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. HOWEVER, WINDS ARE
EXPECTED TO INCREASE BEGINNING MID DAY TODAY, AND BY EARLY WEDNESDAY
MORNING, COULD HAVE GUSTS NEAR 20KTS. WIND DIRECTION WILL SHIFT FROM
MOSTLY SOUTHERLY THROUGH THE DAY TODAY TO WESTERLY BY LATE THIS
EVENING.

OUTLOOK...
WEDNESDAY AND THURSDAY...WHILE SEAS ARE EXPECTED TO REMAIN GENERALLY
BELOW SCA LEVELS, NORTHWEST WIND GUSTS SHOULD REACH THE SCA THRESHOLD
OF 25 KNOTS AT TIMES LATE WEDNESDAY AFTERNOON THROUGH
THURSDAY...POSSIBLY 30 KT.  SCA EXPECTED.   CONFIDENCE: ABOVE
AVERAGE.

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...SCA LIKELY AT NIGHT...POSSIBLY A GALE BUT FOR NOW SCA
IS FAVORED FOR A START.  CONFIDENCE: AVERAGE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...DRAG
NEAR TERM...JOHNSON
SHORT TERM...JOHNSON
LONG TERM...HEAVENER
AVIATION...HEAVENER/JOHNSON
MARINE...DRAG/HEAVENER/JOHNSON






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