Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 210841
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
441 AM EDT SUN SEP 21 2014

.SYNOPSIS...
LOW PRESSURE OFF THE CAROLINA COAST WILL MOVE NORTHEAST OFF THE
MID-ATLANTIC COAST TODAY WHILE A COLD FRONT APPROACHES FROM THE
WEST. THE FRONT IS EXPECTED TO MOVE THROUGH THE MID-ATLANTIC STATES
TONIGHT. HIGH PRESSURE BUILDING IN FROM THE MIDWEST EARLY IN THE
WEEK WILL PERSIST OVER THE AREA THROUGH THE END OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TWO FEATURES WILL INFLUENCE TODAYS WEATHER ACROSS OUR AREA.

THE FIRST IS THE COASTAL LOW OFF OF THE CAROLINAS MOVING UP THE
EASTERN SEABOARD TODAY. THIS LOW CONTINUES TO LOOK LIKE IT WILL
REMAIN OFFSHORE. HOWEVER, IT IS SENDING SOME SHOWERS UP OUR WAY,
MAINLY ALONG THE COASTAL AREAS. THERE ARE SOME ISOLATED
THUNDERSTORMS EMBEDDED IN THESE SHOWERS SO WE HAVE ADDED THEM INTO
THE FORECAST THROUGH THIS MORNING RIGHT ALONG THE COAST AND OVER THE
WATER. THIS LOW SHOULD BE OFF OF OUR COASTAL WATERS BY THIS
AFTERNOON AND THEN WILL QUICKLY MOVE TO THE NORTHEAST.

THE SECOND FEATURE IS A LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT
LAKES. THIS LOW WILL DRAG A COLD FRONT TOWARDS OUR AREA. HOWEVER,
THIS FEATURE IS A LITTLE SLOWER MOVING AND THE FRONT WILL NOT REACH
OUR WESTERN AREAS UNTIL THIS AFTERNOON/EARLY EVENING. SOME SHOWERS
WILL DEVELOP AHEAD OF THE MAIN FRONT AND THUNDER, IF IT OCCURS,
WOULD BE PRETTY ISOLATED AS CONVECTIVE PARAMETERS DO NOT LOOK ALL
THAT ROBUST TODAY. BEST CHANCES FOR THUNDER WOULD BE TOWARD THIS
AFTERNOON.

TODAY WILL START OFF PRETTY CLOUDY, ESPECIALLY THE FURTHER EAST AND
TOWARDS THE COAST YOU GO. IN ADDITION TO THE CLOUDS, SOME FOG WILL
EXIST AND WITH THE LOWER SUN ANGLE (THINK MORE OF A MARCH SUN ANGLE)
THIS TIME OF YEAR, IT WILL TAKE A BIT LONGER BEFORE WE REALLY START
TO CLEAR OUT. WE DO EXPECT THAT BY LATE MORNING/EARLY AFTERNOON, THE
SUN SHOULD START TO MAKE AN APPEARANCE AND WE WILL CERTAINLY SEE
SURFACE TEMPERATURES RESPOND.

WITH THE WARMER OVERNIGHT TEMPERATURES, WE HAVE A PRETTY GOOD
STARTING POINT TO SEE TEMPS RISE TODAY. EXPECT HIGHS TO REACH INTO
THE UPPER 70S TO LOWER 80S ACROSS THE REGION AS WE HAVE A MORE
SOUTHWESTERLY FLOW DEVELOPING THROUGH THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE COLD FRONT WILL BE THE FEATURE IMPACTING OUR AREA TONIGHT.
THE FRONT WILL MOVE INTO THE AREA THIS EVENING AND THEN SLOWLY
PUSH ITS WAY THROUGH, MAKING ITS WAY OFFSHORE BY LATE TONIGHT OR
EARLY MONDAY.

THE FRONT WILL HAVE SOME SHOWERS ASSOCIATED WITH IT AND MAYBE A FEW
RUMBLES OF THUNDER, ALTHOUGH INSTABILITY DOES NOT LOOK AT ALL
IMPRESSIVE. WITH THE SUN SETTING EARLIER AT THIS TIME OF YEAR, WE
WILL LOSE SOME OF THE OOMPH NEEDED TO HELP PRODUCE THUNDERSTORMS.

THE FRONT MOVES OFFSHORE LATE TONIGHT AND WE WILL SEE A WIND SHIFT
TO THE NORTHWEST OCCUR. COOLER AIR WILL START TO MOVE IN TOWARD
MORNING BUT WILL NOT ARRIVE IN TIME TO IMPACT OVERNIGHT TEMPS.
EXPECT LOWS TO BE IN THE 50S TO LOWER 60S ACROSS THE REGION.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
RATHER BENIGN WEATHER IS EXPECTED THROUGH THE ENTIRE EXTENDED
FORECAST PERIOD OF MONDAY THRU SATURDAY. THE COLD FRONT FORECAST
TO MOVE ACROSS THE AREA TONIGHT SHOULD BE OFF THE MID-ATLANTIC
COAST BY MONDAY MORNING. HIGH PRESSURE BUILDING IN FROM THE WEST
BEHIND THE FRONT ON MON AND TUE IS EXPECTED TO STRENGTHEN OVER NEW
ENGLAND BY WED AND THU...AND THEN SHIFT SLIGHTLY WEST TO THE LOWER
GRTLKS AND MID-ATLANTIC BY FRI/SAT. MEANWHILE AN UPPER TROF OVER
THE ERN US ON MONDAY WILL GIVE WAY TO AN UPPER RIDGE BUILDING OVER
THE REGION BY MID WEEK AND CONTINUING INTO NEXT WEEKEND.

THE 12Z ECMWF SHOWED AN UPPER LOW DEVELOPING OVER THE MID-ATLANTIC
BY THE LATTER PART OF THE WEEK. HWVR THIS SOLN SEEMS TO BE OUT OF
LINE WITH OTHER MODELS INCLUDING THE EURO ENSEMBLE...ACCORDING TO
WPC...AND NOW THE NEW 00Z ECMWF SHOWS MORE OF A WEAKNESS IN THE
UPPER RIDGE RATHER THAN A CLOSED LOW. STILL...WITH EASTERLY/ONSHORE
FLOW AROUND THE NEW ENGLAND HIGH PRES...HAVE ACCEPTED WPC POPS
OVER DELMARVA AND SRN NJ FOR THU AND THU NIGHT...BUT WITH A SMALL
DOWNWARD ADJUSTMENT.

LOW-LEVEL COLD ADVECTION WILL BE IN PLACE FOR MON AND TUE BUT SHOULD
BECOME NEUTRAL BY MID-WEEK...WITH A WARMING TREND BY WEEKS END.


&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

TODAY...MVFR/IFR CONDITIONS WILL CONTINUE THROUGH LATE THIS MORNING.
SKIES SHOULD START TO CLEAR OUT AND CONDITIONS WILL IMPROVE TO VFR
BETWEEN 14-16Z ACROSS THE TERMINALS. WINDS WILL BE OUT OF THE
SOUTHWEST AROUND 10 KNOTS OR LESS. A MORE EASTERLY FLOW IS LIKELY
ALONG THE COAST AND AT KACY THROUGH EARLY THIS AFTERNOON. SOME
SHOWERS ASSOCIATED WITH A COASTAL LOW PRESSURE SYSTEM CONTINUE TO
MOVE NORTHWARD ALONG THE COAST. IT LOOKS LIKE THESE SHOWERS WILL
REMAIN MOSTLY OFFSHORE BUT MAY BRIEFLY IMPACT KACY THROUGH THIS
MORNING.

TONIGHT...A COLD FRONT WILL CROSS THE REGION TONIGHT. WINDS WILL
SHIFT FROM THE SOUTHWEST TO THE NORTHWEST BEHIND THE FRONTAL
PASSAGE.

THERE IS A CHANCE FOR SOME SCATTERED SHOWERS AHEAD OF AND ALONG THE
COLD FRONT. BEST CHANCES ARE LATER THIS AFTERNOON THROUGH THIS
EVENING.

OUTLOOK...
MONDAY...NW WIND GUSTS AROUND 20 KT ARE POSSIBLE MONDAY IN
ASSOCIATION WITH HIGH PRESSURE BUILDING IN BEHIND A COLD FRONT.
SOME STRATO-CU MAY DEVELOP IN THIS SETUP, WHICH COULD MAY RESULT
IN A PERIOD MVFR CIGS, MOST LIKELY FOR RDG/ABE TERMINALS.

MONDAY NIGHT THROUGH THURSDAY...VFR AND LIGHT WINDS EXPECTED.

&&

.MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH NOON TODAY FOR OUR
OCEAN FRONT.

SEAS WILL START TO SUBSIDE THIS AFTERNOON BEFORE STARTING TO RAMP UP
AGAIN AS LOW PRESSURE PASSES TO THE EAST OF OUR AREA WATERS. THERE
LOOKS TO BE A PERIOD OF SUB-ADVISORY CONDITIONS AND THROUGH THIS
AFTERNOON INTO THIS EVENING. WILL HOLD OFF ON EXTENDING THE SMALL
CRAFT ADVISORY AT THIS TIME.

SHOWERS WITH EMBEDDED THUNDERSTORMS, ASSOCIATED WITH THE LOW
PRESSURE SYSTEM TO OUR SOUTH, WILL CONTINUE TO MOVE THROUGH THE
WATERS THIS MORNING. EXPECT THEM TO GRADUALLY MOVE NORTH AND EAST AS
THE LOW MAKES ITS WAY UP THE MIDDLE ATLANTIC COAST.

OUTLOOK...
MONDAY AND MONDAY NIGHT...A COLD FRONT WILL MOVE THRU THE WATERS
EARLY MONDAY MORNING RESULTING IN A WIND SHIFT FROM SW TO NW. POST-
FRONTAL NW WINDS OF 15-20 KT GENERALLY EXPECTED BUT CANNOT RULE
OUT LOCALLY STRONGER GUSTS ON MONDAY INTO MONDAY NIGHT. WITH THE
NW FLOW SEAS COULD BUILD UP TO 5 FEET WELL OFFSHORE. HOWEVER THIS
IS NOT CERTAIN AND WITH SCA CURRENTLY IN EFFECT AND A LULL
EXPECTED THIS AFTN/EVE...WILL NOT ISSUE ANOTHER SCA AT THIS TIME.

TUESDAY THROUGH THURSDAY...SUB-SCA CONDITIONS EXPECTED FOR TUE AND
WED BUT INCREASING EAST FLOW BY THU COULD BUILD SEAS TO NEAR 5 FEET...
ESPECIALLY CAPE MAY AND SOUTH.

&&


.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ450>455.

&&

$$
SYNOPSIS...AMC
NEAR TERM...MEOLA
SHORT TERM...MEOLA
LONG TERM...AMC
AVIATION...AMC/MEOLA
MARINE...AMC/MEOLA





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