Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 041005
AFDPHI

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

.SYNOPSIS...
LOW PRESSURE OVER SOUTHEAST VIRGINIA 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. SHOWERS WILL
CONTINUE TO DEVELOP/SPREAD ACROSS THE AREA THIS MORNING...HWVR THE
BEST CHC FOR THE EARLY MORN HOURS LOOKS TO BE N/W OF PHL BASED ON
THE REGIONAL RADAR LOOP. LATER IN THE DAY AS LOW PRES MOVES EAST OF
DELMARVA...POPS MAY BE MORE LIKELY S/E BUT CONFIDENCE IS NOT HIGH
AT THIS TIME. CLOUD 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.

&&

.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 DEWPOINT- 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 SKYCOVER. CONFIDENCE: AVERAGE OR
BELOW AVERAGE.

FRIDAY...PROBABLY DRYING OUT AFTER THURSDAYS ANTICIPATED SHORT
WAVE PASSAGE. CONFIDENCE: AVERAGE OR BELOW AVERAGE.

&&

.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

VFR CONDS EARLY THIS MORNING WILL WORSEN SOMEWHAT AFTER DAYBREAK 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 (SATURDAY 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
SHORT TERM...AMC
LONG TERM...DRAG 604A
AVIATION...AMC/DRAG
MARINE...AMC/DRAG
TIDES/COASTAL FLOODING...
RIP CURRENTS...


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