Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 212002
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
402 PM EDT TUE OCT 21 2014

.SYNOPSIS...
BROAD LOW PRESSURE LOCATED OVER THE CHESAPEAKE BAY REGION THIS
AFTERNOON WILL DRIFT OFF THE COAST TONIGHT. THE LOW IS FORECAST TO
MOVE SLOWLY NORTH AND NORTHEASTWARD REACHING THE WATERS OFF CAPE
COD ON THURSDAY NIGHT AND ARRIVING IN NOVA SCOTIA ON FRIDAY NIGHT.
HIGH PRESSURE IS ANTICIPATED TO BUILD INTO OUR REGION FROM THE
SOUTHWEST FOR FRIDAY INTO SATURDAY. A COLD FRONT APPROACHING FROM
NORTHWEST IS EXPECTED ON SATURDAY NIGHT WITH ANOTHER AREA OF HIGH
PRESSURE FOLLOWING FOR SUNDAY AND FOR THE EARLY PART OF THE NEW
WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
REGIONAL RADAR IS STARTING TO SHOW MORE SCATTERED SHOWERS MOVING
INTO OUR WESTERN ZONES AT THIS TIME. WHAT WAS ONCE A BETTER
DEFINED MCV OUT IN WESTERN PENNSYLVANIA LOOKS TO BE LOSING IT
LUSTER BUT IT SHOULD NOT COMPLETELY WASH OUT AS IT MOVES CLOSER TO
OUR CWA. THE CURRENT AREA OF ACTIVITY IS EXPECTED TO INCREASE
THROUGH THE LATE EVENING HOURS AND BEGIN TO WANE AS IT LOSES
BETTER SUPPORT FROM THE MID-LEVEL TROUGH TO OUR WEST. THE MID-
LEVEL TROUGHING TO OUR WEST DIVES FURTHER SOUTHWARD TO OUR
IMMEDIATE WEST LATE TONIGHT AS MORE AND MORE ENERGY IS TRANSFERRED
TO A COASTAL LOW PRESSURE JUST OFFSHORE OF DELMARVA.

WE CATERED THE POPS WITH LIKELIES ACROSS OUR NORTHERN FRINGE AND
CHANCE ELSEWHERE, EARLY AND THEN BRING IN LIKELY ACROSS OUR
SOUTHERN ZONES LATER TONIGHT WITH THE MOVEMENT OF THE CLOSING MID-
LEVEL LOW AND OVERHEAD ENERGY TRANSFER TO THE COAST.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
GENERALLY SPEAKING THE POOR MANS 500MB ENSEMBLE SHOWS GOOD
AGREEMENT AMONG THE 12Z OPERATIONAL MODELS. ALL SHOW THE TROUGHING
TO OUR WEST CLOSING OFF TONIGHT AS MULTIPLE IMPULSES MOVE THROUGH
ITS BASE OVER THE NEXT COUPLE OF DAYS. AS IT CONTINUES TO CLOSE
OFF A BETTER DEFINED SURFACE LOW TAKES SHAPE JUST OFFSHORE OF THE
DELMARVA/SOUTHERN NEW JERSEY COASTLINE. THE STRONGEST OF THE MID-
LEVEL IMPULSES TONIGHT DIVES INTO THE BASE OF THE TROUGH AS IT AND
IT BEGINS TO CLOSE OFF BUT DEEPENS THE COASTAL LOW PRESSURE. AMPLE
ATLANTIC MOISTURE WILL BE IN PLACE COMBINED WITH GOOD CYCLONIC JET
DYNAMICS AND DIV-Q FIELD TO SEE CATEGORICAL POPS ACROSS A BROAD
PORTION OF OUR EASTERN HALF WITH MODERATE RAINFALL EXPECTED.

TEMPERATURES WILL ONLY BE ALLOWED INTO THE UPPER-50S TO MAYBE THE
LOW-60S IN THE SOUTHERN PLACES. THE PRESSURE GRADIENT TIGHTENS AND
WITH SOME MIXING OCCURRING IN THE AFTERNOON HOURS GUSTS COULD TOP
OUT AROUND 25 WITH A NORTHERLY FLOW...RAW INDEED.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
A MID LEVEL LOW IS FORECAST TO BE LOCATED OFF THE DELMARVA COAST
ON WEDNESDAY EVENING. THE FEATURE WILL LIFT SLOWLY NORTH AND
NORTHEASTWARD PASSING OVER THE WATERS OFF CAPE COD ON FRIDAY
MORNING.

WE CONTINUE TO ANTICIPATE RAIN FOR WEDNESDAY NIGHT. THE RAIN
SHOULD REMAIN FAIRLY LIGHT IN MUCH OF EASTERN PENNSYLVANIA AND
NORTHEASTERN DELAWARE. HOWEVER, MODERATE TO OCCASIONALLY HEAVY
RAIN IS POSSIBLE IN NEW JERSEY AND DELAWARE, CLOSER TO THE MID
LEVEL LOW.

A FAIR AMOUNT OF LINGERING WRAP-AROUND MOISTURE WILL REMAIN OVER
OUR REGION ON THURSDAY. WE ARE ANTICIPATING A CLOUDY AND DAMP DAY
WITH A NORTHWEST WIND AND OCCASIONAL LIGHT RAIN. WE HAVE GONE WITH
THE LOW END OF THE TEMPERATURE GUIDANCE. HIGH TEMPERATURES SHOULD
BE MAINLY IN THE 50S IN OUR FORECAST AREA.

GRADUAL DRYING IS EXPECTED FROM SOUTHWEST TO NORTHEAST DURING THE
COURSE OF THURSDAY NIGHT AND FRIDAY AS THE MID LEVEL LOW CONTINUES
TO MOVE AWAY FROM OUR REGION. TEMPERATURES SHOULD BEGIN TO EASE
BACK TOWARD NORMAL LEVELS FOR LATE OCTOBER.

A SHORT WAVE ROTATING AROUND THE MID LEVEL LOW IS FORECAST TO
PASS OVERHEAD ON FRIDAY NIGHT. ANOTHER MID LEVEL SHORT WAVE FROM
THE NORTHWEST IS EXPECTED FOR SATURDAY NIGHT ALONG WITH AN
ASSOCIATED SURFACE COLD FRONT. THE COLD FRONT SHOULD HAVE LIMITED
MOISTURE ASSOCIATED WITH IT, SO WE ARE NOT ANTICIPATING ANY
PRECIPITATION AT THAT TIME. TEMPERATURES ARE FORECAST TO BE NEAR
NORMAL OVER THE WEEKEND.

RIDGING AT THE SURFACE AND ALOFT ARE ANTICIPATED FOR MONDAY AND
TUESDAY WITH A MOSTLY CLEAR SKY AND SLIGHTLY ABOVE NORMAL
TEMPERATURES.

&&

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

THIS AFTERNOON - TONIGHT...VFR TO MVFR/IFR. LIGHT WESTERLY FLOW
EXPECTED WITH SHOWERS OVERSPREADING FROM WEST TO EAST BEFORE
SHUTTING OFF LATE THIS EVENING. ISOLATED THUNDER POSSIBLE THROUGH
LATE THIS EVENING BUT NOT CONFIDENT ON PLACEMENT SO LEFT OUT OF
TAFS...BETTER CHANCE FURTHER EAST. START TO SEE MVFR/IFR CIGS AND
VSBYS AS LOW PRESSURE MOVES NEARBY. RAIN EARLY WEDNESDAY MORNING
COULD BE HEAVY AT TIMES AND MAY REDUCE VSBYS INTO THE IFR RANGE.
WINDS VEER TOWARDS THE NORTHEAST AND INCREASE TOWARDS 10 KNOTS.
MEDIUM CONFIDENCE.

WEDNESDAY...MOSTLY MVFR. RAIN WILL PREVAIL A MAJORITY OF THE DAY,
ESPECIALLY FROM PHL EASTWARD. NORTHEAST WINDS AROUND 10 TO 15
KNOTS WITH GUSTS UP TO 25 KNOTS...SLIGHT BACKING TOWARDS THE NORTH
LATE IN THE PERIOD. MEDIUM CONFIDENCE.

OUTLOOK...
WEDNESDAY NIGHT AND THURSDAY...CONDITIONS VARYING BETWEEN VFR AND
MVFR IN PERIODS OF RAIN.

THURSDAY NIGHT...MAINLY VFR WITH A CHANCE OF SHOWERS.

FRIDAY THROUGH SUNDAY...MAINLY VFR.

&&

.MARINE...
TONIGHT...SUB-SCA CONDITIONS EXPECTED TONIGHT. LIGHT SOUTHWEST-
WEST FLOW WITH SHOWERS OVERSPREADING FROM THE WEST AND THEN
SOUTHWEST.

WEDNESDAY...WE UPGRADED TO GALES ACROSS THE LOWER BAY AND
SOUTHERN TWO ZONES STARTING WEDNESDAY AFTERNOON AS LOW PRESSURE
JUST OFFSHORE WRAPS UP. SMALL CRAFT ELSEWHERE THROUGH THE
THURSDAY. NORTHEAST WINDS INCREASE TO 20 TO 25 KNOTS WITH GUSTS
INTO THE MID-30S LIKELY SOUTHWARD AND LOW-30S NORTHWARD. SEAS
INCREASE TO AROUND 5 TO 6 FEET LATE.

OUTLOOK...
WEDNESDAY NIGHT AND THURSDAY...A GALE WARNING IS IN PLACE FOR THE
WATERS OFF DELAWARE AND FOR THE LOWER PART OF DELAWARE BAY. A
SMALL CRAFT ADVISORY IS IN EFFECT FOR OUR REMAINING WATERS. WE ARE
EXPECTING A GUSTY NORTHWEST WIND.

THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY WIND GUSTS OF
25 TO 30 KNOTS ARE POSSIBLE.

SATURDAY THROUGH SUNDAY...NO MARINE HEADLINES ARE ANTICIPATED.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 6 PM EDT THURSDAY
     FOR ANZ450>453.
     GALE WARNING FROM 2 PM WEDNESDAY TO 11 AM EDT THURSDAY FOR
     ANZ431-454-455.
     SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 6 AM EDT THURSDAY
     FOR ANZ430.

&&

$$

SYNOPSIS...IOVINO
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...IOVINO
AVIATION...IOVINO/HEAVENER
MARINE...IOVINO/HEAVENER






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