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Area Forecast Discussion
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000
FXUS61 KPHI 040435
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1235 AM EDT FRI SEP 4 2015

.SYNOPSIS...
A BACK DOOR COLD FRONT WILL PUSH ACROSS THE AREA OVERNIGHT INTO
FRIDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION FROM THE NORTH
SATURDAY, BEFORE MOVING OFFSHORE SUNDAY. HOWEVER, IT WILL CONTINUE
AFFECT THE AREA THROUGH EARLY NEXT WEEK. A COLD FRONT IS EXPECTED
TO APPROACH THE AREA FROM THE WEST LATE WEDNESDAY, THEN PUSH
ACROSS THE AREA AROUND THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A SURFACE TROUGH EXTENDED INLAND FROM THE WATERS OFF NEW JERSEY
TO MARYLAND AND NORTHERN VIRGINIA SHORTLY AFTER MIDNIGHT. THE BACK
DOOR COLD FRONT WAS A BIT DIFFUSE AND DIFFICULT TO FIND. HOWEVER,
IT APPEARED TO EXTEND ACROSS NORTHEASTERN PENNSYLVANIA, NORTHERN
NEW JERSEY AND LONG ISLAND. THE BOUNDARY WILL CONTINUE TO DROP
INTO THE SURFACE TROUGH OVERNIGHT WITH BOTH FEATURES THEN SINKING
SLOWLY TO THE SOUTH.

HIGH CLOUDS AND SCATTERED STRATOCUMULUS AND ALTOCUMULUS WILL
REMAIN OVERHEAD DURING THE NIGHT.

THERE WAS ONE LINGERING THUNDERSTORM IN OUR FORECAST AREA AROUND
1230 AM. IT WAS DRIFTING ACROSS THE BORDER FROM EXTREME
SOUTHEASTERN PENNSYLVANIA INTO THE NORTHEASTERN TIP OF DELAWARE.
IT SHOULD CONTINUE TO WEAKEN GRADUALLY.

A LIGHT NORTHEAST TO EAST SURFACE FLOW WILL LIKELY BECOME
ESTABLISHED IN OUR REGION AS THE COLD FRONT PASSES. MINIMUM
TEMPERATURES ARE ANTICIPATED TO FAVOR THE UPPER 60S AND LOWER 70S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SATURDAY/...
THE BACK DOOR COLD FRONT WILL CONTINUE TO PROGRESS SOUTHWESTWARD
THRU THE AREA ON FRIDAY. THERE WILL BE A LAG BETWEEN THE FROPA AND
ARRIVAL OF THE COOLER AIR. THE FORMER WILL OCCUR IN THE AFTERNOON,
WHEN HIGH PRESSURE OVER SOUTHERN QUEBEC NOSES SOUTHWARD DOWN THE
EASTERN SEABOARD. THIS PRESSURE SURGE WILL BE ACCOMPANIED BY
BREEZY E TO NE WINDS THAT WILL ADVECT COOLER AIR INTO THE AREA.
THEREFORE, THERE IS A CONSIDERABLE TEMPERATURE GRADIENT TOMORROW
AFTERNOON, RANGING FROM THE 70S ALONG THE COAST AND IN NORTHERN NJ
TO NEAR 90F IN EASTERN MD. ANOTHER REASON FOR THE LARGE
TEMPERATURE GRADIENT IS THE CLOUD COVER, WHICH WILL BE HIGHER
ACROSS NJ AND NORTHEAST PA THAN FARTHER TO THE SOUTH AND WEST.

WITH MORE STABLE MARINE AIR ADVECTING INLAND DURING THE DAY, THE
BEST CHANCE FOR SHOWERS AND STORMS WILL BE INLAND (OUT TOWARD
READING AND THE EASTERN SHORE OF THE CHESAPEAKE BAY) AND DURING
THE PEAK HEATING HOURS OF THE AFTERNOON. THE COVERAGE OF SHOWERS
AND STORMS LOOKS TO BE SCATTERED IN THESE FAR WESTERN ZONES AND
MORE ISOLATED CLOSER TO THE DELAWARE VALLEY.

&&

.LONG TERM /SATURDAY THROUGH FRIDAY/...
ONCE THE FRONT PUSHES SOUTH OF THE AREA FRIDAY EVENING, ANY
REMAINING SHOWERS WILL MOVE SOUTH OF THE AREA OR DISSIPATE. HIGH
PRESSURE WILL THEN BUILD BACK ACROSS THE EAST COAST FROM THE NORTH
FROM SATURDAY, BEFORE IT MOVES OFFSHORE SUNDAY. THE HIGH WILL
CONTINUE TO AFFECT THE AREA THROUGH TUESDAY, WHICH WILL PROVIDE
MOSTLY DRY WEATHER ACROSS THE AREA. THERE IS SOME GUIDANCE
INDICATING THERE MAY BE SOME SHOWER ACTIVITY ON THE SOUTHERN EDGE
OF THE HIGH PRESSURE ACROSS THE SOUTHERN PORTIONS OF THE AREA OVER
THE WEEKEND INTO MONDAY. ALL INDICATIONS ARE ANY PRECIPITATION
SHOULD BE LIGHT.

ONE THING OF NOTE IS MODELS ARE INDICATING AN AREA OF LOW
PRESSURE DEVELOPING AND STRENGTHENING SLIGHTLY OFF THE SOUTHEAST
COAST OVER THE WEEKEND. THEY MOVE THIS LOW NORTHWARD, WHILE
WEAKENING IT, BUT KEEP IT OFFSHORE AS IT GETS CAUGHT UP IN THE
SOUTHWEST FLOW ALOFT BY TUESDAY. DEPENDING ON HOW CLOSE IT GETS,
THERE COULD BE SOME SCATTERED SHOWERS ACROSS THE AREA ON TUESDAY.

MODELS HAVE SLOWED DOWN A COLD FRONT, WHICH IS NOW FORECAST TO
BEGIN TO APPROACH THE AREA LATE WEDNESDAY AND MOVE ACROSS THE AREA
THURSDAY. THERE IS A SLIGHT CHANCE FOR SHOWERS TO AFFECT THE
NORTHWEST PORTIONS OF THE AREA WEDNESDAY, BUT IT LOOKS MORE LIKELY
WEDNESDAY NIGHT AND THURSDAY FOR THE POTENTIAL FOR PRECIPITATION
FOR THE REST OF THE AREA.

TEMPERATURES COOL OFF SLIGHTLY SATURDAY, FOLLOWED BY A WARMING
TREND SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

OVERNIGHT...A BACK DOOR FRONT WILL SAG SOUTHWARD IN OUR AREA.
LIGHT AND VARIABLE WINDS SHOULD BECOME NORTHEAST WITH A VFR CIG
MOVING IN BEHIND THE FRONT. THERE IS A WINDOW OF OPPORTUNITY WITH
LIGHTER WINDS AND RELATIVELY CLEARER SKIES WHEN SOME FOG COULD
FORM, ESPECIALLY AT MORE RURAL AIRPORTS AND TERMINALS. CONFIDENCE
IS AVERAGE AND WE HAVE SOME MVFR RESTRICTIONS, EVEN IFR AT KMIV
(BECAUSE OF THEIR MURKY START THIS EVENING). WE HAVE A MENTION OF
A SHOWER AT KILG UNTIL 0700Z BASED ON THE RADAR.

FRIDAY...BEHIND THE FRONT NORTHEAST VEERING TO THE EAST WINDS
SHOULD AVERAGE AROUND 10 KNOTS. A STRATOCU DECK LEVEL VFR CIG IS
PREDICTED TO PREVAIL. THERE MAY BE ENOUGH INSTABILITY ALOFT FOR
WIDELY SCATTERED SHOWERS AND TSTMS TO OCCUR AT WESTERN AND
SOUTHWESTERN TERMINALS, BUT CONFIDENCE IS TOO LOW TO KNOW WHETHER
THEY WILL BE SPECIFICALLY IMPACTED. CHANCES DECREASES AS THE
AFTERNOON PROGRESSES ALL TERMINALS.

OUTLOOK...
FRIDAY NIGHT-TUESDAY NIGHT...MOSTLY VFR. GUSTY E-NE WINDS AROUND
15- 20 KNOTS SATURDAY AFTERNOON. PATCHY FOG/STRATUS POSSIBLE
AROUND DAYBREAK EACH DAY.

&&

.MARINE...
NO HAZARDS ON THE MARINE ANTICIPATED THRU FRIDAY MORNING. NELY
WINDS WILL INCREASE THOUGH DURING THE DAY FRIDAY AND SCA
CONDITIONS ARE LIKELY TO DEVELOP LATER THAT AFTERNOON IN OUR
NORTHERN ZONES WITH 15- 20 KT WINDS (GUSTS TO 25 KT) AND SEAS OF
4-5 ARE FORECAST TO ARRIVE.

OUTLOOK...
FRIDAY NIGHT-SATURDAY NIGHT...SEAS REMAIN ABOVE SMALL CRAFT
ADVISORY LEVELS WITH THE EASTERLY FETCH BEHIND THE BACKDOOR COLD
FRONT FRIDAY NIGHT INTO SATURDAY. WINDS REMAIN ABOVE SMALL CRAFT
ADVISORY LEVELS BEHIND THE BACKDOOR COLD FRONT AS WELL FRIDAY
NIGHT INTO SATURDAY.

SUNDAY-TUESDAY NIGHT...SEAS EXPECTED TO SUBSIDE BACK BELOW SMALL
CRAFT ADVISORY CONDITIONS BY SUNDAY. WINDS AND SEAS THEN EXPECTED
TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH TUESDAY NIGHT.

&&

.RIP CURRENTS...
THE THREAT FOR DANGEROUS RIP CURRENTS WILL BE ENHANCED FRIDAY AND
THE UPCOMING LABOR DAY WEEKEND.

FOR THE FIRST LOOK FOR FRIDAY, WE WILL CARRY A MODERATE RISK FOR
MONMOUTH AND OCEAN COUNTIES AND LOW RISK ELSEWHERE. THIS WILL BE
REACCESSED OVERNIGHT AS ITS A TIMING ISSUE AS TO HOW QUICKLY WILL
THE NORTHEAST WINDS RAMP AS WE MOVE FARTHER SOUTH ALONG THE NEW
JERSEY AND THEN DELAWARE COASTS. COULD BE A HYBRID SCENARIO OF LOW
BECOMING MODERATE AS THE AFTERNOON, EVENING CONTINUES. RIGHT NOW
CONDITIONS HAVE BEEN REPORTED TO US AS BEING VERY CALM.

THE NORTHEASTERLY WINDS SURGE BEHIND A BACKDOOR COLD FRONT OF 10
TO 15 KT WILL ARRIVE FRIDAY MORNING AND INCREASE TO 15-20 KT
FRIDAY AFTERNOON THRU SATURDAY. WAVES WILL BUILD IN RESPONSE TO
THIS WIND SURGE, FORECASTED TO INCREASE TO 4-6 FT BY FRIDAY NIGHT.
THE WINDS AND WAVES ALONG THE COAST SHOULD GRADUALLY SUBSIDE LATE
SATURDAY INTO SUNDAY. SUBJECT TO CHANGE SEVERAL DAYS OUT, BUT IN-
HOUSE GUIDANCE IS SUGGESTING A MODERATE POSSIBLY NEAR HIGH FOR
SATURDAY. THE RISK SHOULD SUBSIDE A BIT BY SUNDAY BUT IT MAY STILL
BE MODERATE.

IT IS PARTICULARLY IMPORTANT FOR SAFETY AWARENESS TO SHARE THIS
INFORMATION TO BEACHGOERS AND LIFEGUARDS WITH THE BEACH CROWD
ANTICIPATED TO BE LARGER THAN NORMAL GIVEN IT'S LABOR DAY WEEKEND
AND THERE IS PLENTY OF SUNSHINE IN THE FORECAST.

&&

.CLIMATE...
ALL OUR BIG FOUR CLIMATE SITES HAD THEIR HOTTEST DAY OF THE YEAR
SO FAR TODAY. PHILADELPHIA AND WILMINGTON AT 96, ATLANTIC CITY AT
95 (DAILY RECORD) AND ALLENTOWN AT 94. IN PHILADELPHIA THIS IS THE
FIRST TIME SINCE 1970 THAT THE HOTTEST DAY OF THE YEAR HAS
OCCURRED IN SEPTEMBER.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EDT 
     SATURDAY FOR ANZ452>455.
     SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EDT 
     SATURDAY FOR ANZ450-451.

&&

$$

SYNOPSIS...ROBERTSON
NEAR TERM...IOVINO
SHORT TERM...KLEIN
LONG TERM...ROBERTSON
AVIATION...GIGI/ROBERTSON
MARINE...KLEIN/ROBERTSON
RIP CURRENTS...GIGI
CLIMATE...GIGI



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