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Area Forecast Discussion
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000
FXUS61 KPHI 181804
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
104 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 /THROUGH TONIGHT/...
UPDATE...

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. HIGH TEMPS U30S/L40S - NEAR NRML FOR MID DEC.

WINDS DCRS TNGT. LOWS TNGT RANGING FM THE M20S IN THE POCONOS TO
THE L30S NEAR WILDWOOD.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
ONE LAST SHORT WAVE TROUGH ON THE BACK SIDE OF THE DEPARTING UPPER 
LEVEL LOW WILL APPROACH THE REGION OVER NIGHT, BUT WITH CONTINUED 
DRY AIR ADVECTION IN THE BOUNDARY LAYER, DO NOT EXPECT ANY 
PRECIPITATION, ONLY INCREASING MID AND UPPER LEVEL CLOUDS ACROSS THE 
NORTHERN HALF OF THE REGION. WITH THE SURFACE HIGH SLIDING CLOSER TO 
THE REGION, EXPECT BOUNDARY LAYER WINDS TO DECOUPLE SOON AFTER 
SUNSET. THIS COULD SET UP PRIME RADIATIONAL COOLING CONDITIONS OVER 
THE SOUTHERN HALF OF THE REGION IF PREVIOUSLY MENTIONED MID AND 
UPPER LEVEL CLOUDS STAY CONFINED TO THE NORTH. FOR NOW HOWEVER, HAVE 
GENERALLY STAYED CLOSE TO THE GUIDANCE WHICH IS NEAR NORMALS.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...

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 - SATURDAY...BOTH DAYS LOOK DRY. FRIDAY SHOULD BE DOMINATED 
BY GREAT LAKES HIGH PRESSURE WHICH SHOULD YIELD PARTY CLOUDY SKIES. 
THE PAST COUPLE OF DAYS SATURDAY LOOKED TO BE THE TRANSITION DAY 
INTO THE STORMIER PATTERN BUT WITH THE ONCE EAST COAST STORM BEGAN 
TO TREND WEAKER AND WEAKER WE LOOK TO BE DRIER AND DRIER. THERE IS 
SOME NORTHERN STREAM ENERGY TO CONTEND WITH LATE SATURDAY NIGHT THAT 
COULD TOUCH OFF A FEW SHOWERS AS IT PASSES THROUGH BUT THESE SHOULD 
BE OF LITTLE CONSEQUENCE.

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. IF THIS EASTWARD TREND 
AND CYCLOGENESIS CONTINUES WE COULD BE SINGING A DIFFERENT TUNE OVER 
THE NEXT SEVERAL DAYS. NONE-THE-LESS, LOTS OF MOISTURE, WINDS, AND 
POSSIBLY CONVECTION, ARE LOOKING BETTER AND BETTER...WE CONTINUE THE 
LIKELY POPS THIS FAR IN ADVANCE.

THURSDAY...DEEP LAYER ZONAL FLOW WILL FILL IN ACROSS THE AREA AND 
DRY CONDITIONS WILL PERSIST AS THE COLD FRONT WILL BE THROUGH THE 
AREA AND THE DEEP STACKED LOW WILL REMAIN PARKED OVER THE EASTERN 
GREAT LAKES. 

&&

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

TODAY..."LOW VFR" AT SITES AWAY FM THE SHORE: BKN-OVC 3500-4500 FT.
NW WIND GUSTS 22-30 KT WL BEGIN TO SUBSIDE ARND SUNDOWN.

TONIGHT...VFR WITH SC SLOWLY DIMINISHING THOUGH SC MAY HOLD ON MUCH
OF THE NIGHT NEAR AND JUST N OF KABE/KRDG DUE TO A DEVELOPING INVERSION
NEAR 5000 FT. THERE WILL BE A PERIOD OF MID AND HIGH CLOUDS RACING
EWD BASICALLY NEAR AND SOUTH OF KLNS-KMJX NEAR 06Z/19. GUSTY NW
WINDS SUBSIDE SOMEWHAT...FEW GUSTS 15-20 KT.

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

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

&&

.MARINE...
A SMALL CRAFT ADVISORY CONTINUES OVER THE ATLANTIC COASTAL WATERS
THROUGH LATE THIS AFTERNOON. NORTHWESTERLY WINDS OF 15 TO 25 KT,
WITH OCCASIONAL GUSTS TO 30 KT CAN BE EXPECTED. WINDS SHOULD BEGIN
TO DIMINISH LATE THIS AFTERNOON. HOWEVER, GUSTS NEAR OR ABOVE 20
KT WILL BE POSSIBLE THROUGH THE OVERNIGHT HOURS.

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

&&

.EQUIPMENT...IT IS BLVD THAT TECHNICIANS HV FIXED PROBLEMS W/ THE
DIX 88D AND IT WL BE BACK IN SVC TDA.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR 
     ANZ450>455.

&&

$$
UPDATE...WOODY!/CEB





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