Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 041327
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
927 AM EDT SAT JUL 4 2015

.SYNOPSIS...
LOW PRESSURE OFF THE DELMARVA COAST WILL MOVE OUT TO SEA SOUTH OF
CAPE COD BY THIS EVENING. WEAK HIGH PRESSURE FOLLOWS LATE TONIGHT
AND SUNDAY, THEN SHIFTS OFFSHORE MONDAY. A WARM FRONT MOVES SLOWLY
NORTHEAST THROUGH THE MID ATLANTIC STATES TUESDAY WITH A COLD
FRONT TO FOLLOW LATE WEDNESDAY OR THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE UPPER LEVEL TROF IS PROGRESSING SLOWLY EASTWARD ACROSS THE
GRTLKS AND OH VLY. EXTENSIVE MID CLOUDS AND AREAS OF SHOWERS HAVE
SPREAD ACROSS THE FCST AREA AHEAD OF THE TROF AND NORTH OF THE
QUASI- STNRY FRONTAL BOUNDARY EXTENDING W TO E ACROSS VA.

BASED ON THE LTST RADAR, HAVE INCREASED POPS N AND W IN THE NEAR
TERM AND DECREASED S AND E. THE MOST CURRENT HRRR INDICATES PRECIP
MAY DECREASE IN COVERAGE LATER IN THE DAY AS IT MOVES SEWD AND IF
THAT IS THE CASE, THEN POPS WILL BE OVERDONE. WE`LL REASSESS FOR
THE NEXT UPDATE. OTHERWISE, MADE A FEW MINOR ADJUSTMENTS (UPWARD)
TO TEMPS BASED ON CURRENT OBS.

CLOUDS AND SHOWERS TODAY WILL LIMIT MAX TEMPS TO THE UPPER 60S
N/W AND MID 70S S/E. CHANCE FOR PRECIP SHOULD DECREASE FROM W TO E
FROM MID AFTERNOON ONWARD AS FORCING FOR UVV MOVES AWAY FROM THE
AREA. HWVR CLOUDINESS WILL LINGER AS DRIER AIR WILL BE SMWHT SLOW
TO FILTER IN BEHIND THE LOW.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
FOR TONIGHT...THE UPPER TROF AXIS WILL CONT MOVING EWD AND
OFFSHORE BY SUNDAY MORNING WITH DRIER AIR FILTERING IN BEHIND IT.
WEAK HIGH PRES WILL BUILD IN AT THE SFC. ANY LINGERING SHOWERS
NEAR THE COAST SHOULD MOVE OUT BEFORE DARK ALLOWING FOR FIREWORKS
TO PROCEED. EVENING CLOUDS SHOULD CLEAR FROM THE NW OVER NIGHT
WITH THE DRIER AIR COMING IN. WIND WILL BE RATHER LIGHT ALLOWING
FOR MIN TEMPS GENLY IN THE 50S EXCEPT 60S IN DELMARVA.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
500MB: A TROUGH CENTERED NEAR THE TENNESSEE VALLEY SUNDAY WILL
WEAKEN NORTHEASTWARD ACROSS THE MID ATLANTIC STATES TUESDAY. A
WEAK WEST SOUTHWEST FLOW PREVAILS THEREAFTER WITH WEAK EMBEDDED
DISTURBANCES.

TEMPERATURES: CALENDAR DAY TEMPERATURES NEAR OR SLIGHTLY BELOW
NORMAL ON SUNDAY WARM TO ALMOST 5 DEGREES ABOVE NORMAL TUESDAY AND
WEDNESDAY AND POSSIBLY REMAIN ABOVE NORMAL THURSDAY AND FRIDAY.

FORECAST BASIS: UNLESS OTHERWISE NOTED, THIS 330 AM SATURDAY JULY
4TH FORECAST WAS GENERALLY A 50 50 BLEND OF THE 00Z/4 GFS/NAM MOS
GUIDANCE SUNDAY-MONDAY, 00Z/4 MEX MOS MONDAY NIGHT AND TUESDAY,
THEN THE 0521Z/4 WPC GRIDDED ELEMENTS OF MAX/MIN TEMP, 12 HOUR
POP, 6 HOUR DEW POINT- SKY-WIND FROM TUESDAY NIGHT THROUGH NEXT
FRIDAY WITH THE EXCEPTION OF MAX TEMPS TUESDAY AND WEDNESDAY WHEN
THE 00Z/4 GFS MEX BLENDED WITH THE EVEN WARMER 00Z/4 ECMWF 2M
TEMPS PREVAILED.

THE DAILIES...

SUNDAY...AFTER ANY EARLY MORNING PATCHY FOG DISSIPATES...SCT-BKN
AOA 5000 FT. WEST WIND GUST 15 MPH. CONFIDENCE: ABOVE AVERAGE.

MONDAY....INCREASING CLOUDS. ST/FOG POSSIBLE LATE MONDAY NIGHT?
SOUTH WIND GUST 15 MPH MONDAY AFTERNOON. CONFIDENCE: ABOVE
AVERAGE.

TUESDAY...AREAS OF SHOWERS AND EMBEDDED TSTMS WITH PWAT OF 1.75
TO TO 2 INCHES, MLCAPE 1200J, AND WEAK STEERING WHICH COULD MEAN
SEVERAL INTENSE TSTMS WITH EXCESSIVE SHORT DURATION RAINFALL (POOR
DRAINAGE FLOODING FOR STARTERS). SOUTHERLY WIND GUST 20 MPH. NEAR
90F PHILLY AREA. CONFIDENCE: ABOVE AVERAGE.

WEDNESDAY...LIKELY A HOT DAY. TSTMS LATE IN THE DAY AHEAD OF THE
APPROACHING AND EVENTUALLY SLOWING COLD FRONT. 1000J MLCAPE. COULD
BE STRONG TSTMS E PA. HEAT INDEX RIGHT NOW MODELED 99 PHL AND NEAR
100 DELMARVA. WILL BE REEVALUATED NEXT SEVERAL DAYS. NO HEAT INDEX
ACTION ATTM IN THE MORNING HWO. CONFIDENCE: ABOVE AVERAGE.

THURSDAY...UNCERTAINTY ON TIMING BUT TSTMS ARE IN THE FCST WITH
ANOTHER SHORT WAVE PASSAGE. ALSO UNCERTAINTY ON TEMPS, DEPENDENT
ON TIMING CONVECTIVE RELATED SKY COVER. CONFIDENCE: AVERAGE OR
BELOW AVERAGE.

FRIDAY...PROBABLY DRYING OUT AFTER THURSDAY`S ANTICIPATED SHORT
WAVE PASSAGE. CONFIDENCE: AVERAGE OR BELOW AVERAGE.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

VFR CONDS THIS MORNING WILL WORSEN SOMEWHAT AS AREAS OF SHOWERS
DEVELOP/SPREAD ACROSS THE REGION. SHOWERS ARE AHEAD OF A SHRTWV
TROF MOVING EAST FROM THE OHIO VLY. THERE WILL BE PERIODS OF MVFR
CIGS/VSBYS WITH SOME OF THE HEAVIER SHOWERS. CONDS SHOULD IMPROVE
FROM MID/LATE AFTN ON INTO THE EVENING. CURRENT LIGHT SE WINDS
WILL INCREASE SOME AND BACK TO THE NE AS LOW PRES DEVELOPS LATER
THIS MORNING S OF DELMARVA AND THEN MOVES OFFSHORE.

OUTLOOK...
SUNDAY...VFR SCT-BKN AOA 5000 FT. WEST WIND MAX GUST 15 KT DURING
THE AFTERNOON. PATCHY MVFR FOG POSSIBLE TO START THE DAY AND AGAIN
LATE SUNDAY NIGHT. HIGH CONFIDENCE.

MONDAY...VFR SCT-BKN AOA 5000 FT DURING THE DAY WITH A CHANCE OF
IFR ST/FOG LATE MONDAY NIGHT AHEAD OF A WARM FRONT. SOUTHERLY WIND
MAX GUST 15 KT DURING MONDAY AFTERNOON. HIGH CONFIDENCE.

TUESDAY...VFR SCT-BKN AOA 5000 FT WITH SCT TSTMS AND ASSTD BRIEF
IFR CONDS IN HEAVY RAIN, ESPECIALLY E PA DURING THE AFTN-EVENING.
HIGH CONFIDENCE.

WED...VFR SCT-BKN WITH A PRETTY GOOD CHANCE OF AFTN OR NIGHTTIME
TSTMS. IFR CONDS POSSIBLE IN TSTMS. CONFIDENCE: AVERAGE OR ABOVE
AVERAGE.

&&

.MARINE...
SE WINDS EARLY THIS MORNING WILL BACK TO THE E AND NE LATER THIS
MORNING AND AFTN AS LOW PRES DEVELOPS EAST OF DELMARVA. WIND SPEED
AND WAVES WILL INCREASE SOME TODAY BUT ARE EXPECTED TO REMAIN
BELOW SCA LEVELS. WINDS SHOULD DECREASE AND BECOME NLY TONIGHT AS
THE LOW PRES MOVES AWAY AND WEAK HIGH PRES BUILDS IN.

OUTLOOK...
SUNDAY NIGHT THRU WEDNESDAY...NO MARINE FLAGS ARE ANTICIPATED AS
OF THIS WRITING. CONFIDENCE: AVERAGE

&&

.TIDES/COASTAL FLOODING...
TONIGHT (THIS EVENING). WHILE SOME TIDAL LOCATIONS MAY APPROACH
MINOR TIDAL FLOODING LEVELS, CURRENT DATA INDICATES THEY WILL
REMAIN BELOW ADVISORY THRESHOLD.

&&

.RIP CURRENTS...
THERE IS A MODERATE RISK OF RIP CURRENTS ON SATURDAY ALONG THE
NEW JERSEY SHORE GIVEN THE CONTINUED ONSHORE FLOW AND MODERATE
PERIOD SWELLS. THE RISK IS LOW FOR DELAWARE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...DRAG
NEAR TERM...AMC/NIERENBERG
SHORT TERM...AMC
LONG TERM...DRAG
AVIATION...AMC/DRAG
MARINE...AMC/DRAG
TIDES/COASTAL FLOODING...
RIP CURRENTS...



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