Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 290758
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
358 AM EDT WED OCT 29 2014

.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA TODAY, THEN HIGH PRESSURE
WILL BRIEFLY AFFECT THE AREA THURSDAY. AN AREA OF LOW PRESSURE WILL
MOVE OUT OF THE GREAT LAKES REGION AND SOUTH OF THE AREA ON FRIDAY,
BEFORE COMBINING WITH A DEVELOPING AND STRENGTHENING COASTAL LOW
OFFSHORE OF THE MID ATLANTIC COAST SATURDAY. THIS LOW WILL MOVE WELL
NORTHEAST OF THE AREA ON SUNDAY, THEN HIGH PRESSURE IS EXPECTED TO
BUILD BACK ACROSS THE EAST COAST MONDAY, THEN OFFSHORE TUESDAY AHEAD
OF AN APPROACHING FRONTAL SYSTEM.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
OVERNIGHT WATER VAPOR SATELLITE IMAGERY DEPICTS AN UPPER TROUGH TO
OUR WEST OVER THE GREAT LAKES/MIDWEST REGIONS. THIS TROUGH WAS
ASSOCIATED WITH A VERTICALLY-STACKED CYCLONE JUST SOUTH OF JAMES BAY.
AT THE SURFACE, AN APPROACHING COLD FRONT WAS ANALYZED JUST WEST OF
I-81 IN CENTRAL PA AT 07Z. AN ANAFRONTAL STRUCTURE WAS NOTED WITH
THIS FRONT AS PRECIP AND SOUTHWEST FLOW TRAILS THE BOUNDARY.

THE COLD FRONT COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD THRU
EASTERN PA EARLY THIS MORNING AND OFF THE COAST BY EARLY THIS
AFTERNOON. BASED ON LATEST MODEL GUIDANCE AND OBSERVATIONS, THE
TREND WAS TO SLOW DOWN THE ARRIVAL OF THE SHOWERS AS THE SEPARATION
DISTANCE BETWEEN THE FRONT AND POST-FRONTAL LIFT FROM THE MID-LEVEL
TROUGH GROWS. MADE NOTABLE CHANGES TO THE POP/WX GRIDS TO TAKE THE
DELAY INTO ACCOUNT. SHOWERS NOT EXPECTED TO BE WIDESPREAD AND
RAINFALL AMOUNTS WILL BE LIGHT (GENERALLY AROUND ONE-TENTH INCH).
SLIGHTLY HIGHER AMOUNTS POSSIBLE LATE THIS AFTERNOON AS A WEAK
DISTURBANCE TRAILING THE FRONT IS FORECAST TO TRACKS FROM VA TO THE
DELMARVA, LEADING TO AN ENHANCEMENT OF PRECIP OVER THE SOUTHEASTERN
PART OF THE CWA.

MAX TEMPS RANGE FROM THE LOW 60S IN NORTHEASTERN PA/NW NJ TO AROUND
70F NEAR THE COAST. THESE HIGHS WILL OCCUR ALONG AND AHEAD OF THE
FRONT BEFORE TEMPS FALL BEHIND THE FRONT WHEN THE SHOWERS ARRIVE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE COLD FRONT WILL CONTINUE TO MOVE OFF THE EAST COAST TONIGHT. THE
BACK EDGE OF THE LINGERING SHOWERS BEHIND THE BOUNDARY SHOULD BE
SHIFTING THRU THE I-95 CORRIDOR EARLY THIS EVENING AND OFF THE NJ/DE
COAST AROUND MIDNIGHT.

WEST-NORTHWEST WINDS BEHIND THE FRONT WILL ADVECT COLDER AND
EVENTUALLY DRIER AIR INTO THE REGION. SKIES WILL CLEAR NOT TOO LONG
AFTER PRECIP ENDS- DURING THE EVENING ACROSS EASTERN PA AND
NORTHWEST NJ AND OVERNIGHT FOR COASTAL AREAS. THE PRESSURE GRADIENT
WILL BE STRONG ENOUGH FOR A 5-10 MPH WIND TO CONTINUE OVERNIGHT
ESPECIALLY WITH CAA AIDING IN A MIXED NOCTURNAL BOUNDARY LAYER.
THEREFORE, WENT A COUPLE OF DEGREES ABOVE A MAV/MET BLEND FOR MIN
TEMPS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE IS EXPECTED TO BRIEFLY AFFECT THE AREA THURSDAY
INTO THURSDAY NIGHT. DRY WEATHER AND NEAR NORMAL TEMPERATURES ARE
EXPECTED BEFORE A DECLINE IN THE WEATHER FOR THE UPCOMING WEEKEND.

ON FRIDAY, AN AREA OF LOW PRESSURE WILL BE MOVING OUT OF THE
GREAT LAKES REGION, AND IS EXPECTED TO MOVE TO THE SOUTH OF THE
AREA WHILE A COASTAL LOW DEVELOPS AND STRENGTHENS TO OUR SOUTH. WE
DO NOT EXPECT MUCH, IF ANY PRECIPITATION DURING THE DAY AS THE
PRECIPITATION TIED TO THE SYSTEM TO OUR WEST SHOULD REMAIN TO OUR
NORTH AND WEST UNDERNEATH THE MID/UPPER LOW/TROUGH. AS WE GO INTO
FRIDAY NIGHT, THE MID/UPPER LOW WILL SWING TO OUR SOUTH, WHILE THE
SURFACE LOW WILL BEGIN GETTING ABSORBED BY THE COASTAL LOW. THIS
WILL ALLOW SOME LIGHT PRECIPITATION TO FILL IN ACROSS THE AREA AS
THE MAJORITY OF THE MODEL GUIDANCE IS INDICATING. IT LOOKS LIKE
ANY PRECIPITATION THAT STARTS OUT FRIDAY NIGHT SHOULD BE MOSTLY A
COLD RAIN AS MODELS NOW KEEP 925/850 MB TEMPS ABOVE FREEZING,
ALTHOUGH IT IS STILL POSSIBLE FOR A MIXTURE ACROSS THE FAR
NORTHERN AREAS.

THE MID/UPPER TROUGH WILL SWING OFFSHORE OF THE NORTH CAROLINA
COAST SATURDAY, WHICH WILL ALLOW THE SURFACE LOW TO STRENGTHEN AND
WRAP UP MORE. THE GFS KEEPS THE PRECIP CLOSE TO THE SURFACE AND
MID-LEVEL LOW AND MOSTLY OFFSHORE, BUT THE ECMWF AND CANADIAN KEEP
PRECIP ACROSS THE ENTIRE AREA AND EXTEND IT PRETTY FAR TO OUR
NORTHWEST, SO WE WILL KEEP A CHANCE OF SHOWERS THROUGH THE DAY
SATURDAY. THE MODELS DO SHOW THE PRECIP MOVING TO OUR NORTHEAST
OVERNIGHT SATURDAY AS THE SURFACE AND MID/UPPER LOW PULL TO OUR
NORTHEAST, SO WE`LL HAVE DECREASING POPS OVERNIGHT. THE MODELS
KEEP THE SUB-FREEZING TEMPERATURES OUT OF THE AREA UNTIL
OVERNIGHT SATURDAY, SO THE BEST CHANCE FOR A MIX OR COMPLETE
CHANGE OVER TO SNOW WILL BE SATURDAY NIGHT INTO SUNDAY MORNING IF
THERE IS STILL ANY REMAINING PRECIPITATION, MAINLY ACROSS THE
NORTHERN THIRD OF THE AREA.

WINDS WILL INCREASE SATURDAY INTO SATURDAY NIGHT AS THE PRESSURE
GRADIENT TIGHTENS SIGNIFICANTLY BETWEEN THE COASTAL LOW AND HIGH
PRESSURE TO THE WEST. WINDS LOOK TO GUST BETWEEN 30-40 MPH, WITH
HIGHER GUSTS POSSIBLE CLOSER TO THE COAST.

SUNDAY IS EXPECTED TO BE DRY, BUT COLD AND BLUSTERY AS A STIFF
NORTHWEST FLOW IS EXPECTED AS THE LOW PRESSURE STRENGTHENS TO OUR
NORTHEAST AND HIGH PRESSURE BEGINS APPROACHING FROM THE WEST. WINDS
COULD CONTINUE TO GUST 30-40 MPH ACROSS THE AREA.

HIGH PRESSURE IS EXPECTED TO BUILD TO OUR SOUTH MONDAY AND NOSE ITS
WAY INTO OUR AREA. THIS WILL PROVIDE FAIR WEATHER WITH TEMPERATURES
RISING BACK CLOSER TO NORMAL.

ON TUESDAY, THE HIGH IS EXPECTED TO BUILD OFFSHORE OF THE SOUTHEAST
COAST, WHILE A WARM FRONT LIFTS NORTH OF THE AREA AHEAD OF THE NEXT
APPROACHING COLD FRONT. AS OF NOW, THE FORECAST FOR TUESDAY IS FOR
DRY WEATHER WITH WARMING TEMPERATURES, ALTHOUGH IF THE WARM FRONT
PASSES CLOSE ENOUGH, A FEW SHOWERS MAY BE POSSIBLE.

&&

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

TODAY WILL BE PREDOMINATELY VFR TODAY. A BRIEF PERIOD OF MVFR
CIGS/VSBYS CANNOT BE RULED OUT THIS AFTN WITH HEAVIER SHRA BEHIND A
COLD FRONT BUT CONFIDENCE VERY LOW IN THIS HAPPENING. DELAYED
ARRIVAL OF SHRA WITH THE 06Z TAFS COMPARED TO PREVIOUS TAF ISSUANCES
BY ABOUT 6 HOURS. CLEARING WILL OCCUR FROM WEST TO EAST BETWEEN
00Z-06Z. LIGHT SW WINDS EARLY THIS MRNG BECOME WESTERLY THIS AFTN
AND EVENTUALLY NW TONIGHT.

OUTLOOK...

THURSDAY-FRIDAY...MOSTLY VFR.

FRIDAY NIGHT-SATURDAY NIGHT...LOWER END VFR OR UPPER END MVFR WITH
CIGS 2,500-3,500 EXPECTED. LOWER VSBYS POSSIBLE WITH RAIN SHOWERS.
SNOW SHOWERS POSSIBLE ACROSS NORTHEAST PENNSYLVANIA AND NORTHWEST
NEW JERSEY. GUSTY NORTH-NORTHWEST WINDS SATURDAY INTO SATURDAY NIGHT
25-30 KNOTS, POSSIBLY HIGHER NEAR THE COAST.

SUNDAY...VFR. GUSTY NORTHWEST WINDS 25-30 KNOTS.

&&

.MARINE...
SWLY WINDS GENERALLY 10-15 KT WITH ISOLATED 20 KT GUSTS BEING
OBSERVED AT THE OFFSHORE BUOYS. LATEST BUOY REPORTS SHOW WAVES EVER
SO GRADUALLY INCREASING TO AROUND 4 FT AS OF 07Z. WILL CONTINUE THE
SCA THAT IS IN EFFECT FOR THE COASTAL WATERS THRU 2 PM TODAY FOR
NOW. HOWEVER, IF WINDS/WAVES DO NOT INCREASE OVER THE NEXT FEW HOURS
THEN SCA WILL LIKELY BE CANCELLED.

OUTLOOK...
THURSDAY-FRIDAY NIGHT...SUB-SMALL CRAFT ADVISORY CONDITIONS
EXPECTED, ALTHOUGH WINDS A SEAS WILL BE INCREASING LATE FRIDAY NIGHT.

SATURDAY-SATURDAY NIGHT...INCREASING WINDS SATURDAY AND SATURDAY
NIGHT AS A COASTAL LOW STRENGTHENS. GALE FORCE WINDS LOOKING MORE
LIKELY.

SUNDAY...GALE FORCE WINDS POSSIBLE EARLY, BEFORE DIMINISHING TO
SMALL CRAFT ADVISORY LEVELS LATE IN THE DAY.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
     ANZ450>455.

&&

$$
SYNOPSIS...ROBERTSON
NEAR TERM...KLEIN
SHORT TERM...KLEIN
LONG TERM...ROBERTSON
AVIATION...KLEIN/ROBERTSON
MARINE...KLEIN/ROBERTSON




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