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000
FXUS61 KPHI 110424
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1224 AM EDT FRI JUL 11 2014

.SYNOPSIS...
A STATIONARY FRONTAL BOUNDARY WILL REMAIN OVER THE DELMARVA
TONIGHT BEFORE SLOWLY PUSHING SOUTH OF THE AREA FRIDAY. HIGH
PRESSURE BUILDS IN FROM THE NORTHEAST FRIDAY INTO SATURDAY. RETURN
FLOW DEVELOPS LATE IN THE WEEKEND AND EARLY NEXT WEEK AS HIGH
PRESSURE MOVES OFFSHORE AND AN STRONG UPPER LOW DIGS INTO THE
UPPER MIDWEST. A COLD FRONT WILL APPROACH THE EASTERN SEABOARD
TUESDAY BEFORE MOVING OFFSHORE BY WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE LAST OF THE HEAVY RAIN WAS WRINGING ITSELF OUT OVER THE
WILMINGTON, DELAWARE AREA SHORTLY AFTER MIDNIGHT. THE
PRECIPITATION IS EXPECTED TO DISSIPATE RAPIDLY DUE TO THE LOSS OF
INSTABILITY AND AS THE MID LEVEL SHORT WAVE PASSES OFF THE COAST.
THE REMAINDER OF THE FLASH FLOOD WATCH WAS ALLOWED TO EXPIRE AT
MIDNIGHT.

SCATTERED LIGHT RAIN SHOWERS REMAIN POSSIBLE IN OUR REGION DURING
THE BALANCE OF THE NIGHT. THE WIND IS EXPECTED TO BE LIGHT AND IT
WILL LIKELY FAVOR THE NORTH TO EAST QUADRANT. MINIMUM TEMPERATURES
WILL BE MAINLY IN THE MIDDLE AND UPPER 60S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
THE PESKY FRONTAL BOUNDARY IS EXPECTED TO PUSH BACK OFFSHORE ON
FRIDAY, AND STALL ACROSS THE OCEAN WATERS TO OUR EAST. PW VALUES
CONTINUE TO LOWER THROUGH THE DAY, BUT THE MID-LEVEL THROUGH WILL
BE MOVING OVERHEAD THROUGH THE DAY. THERE WILL REMAIN THE CHANCE
FOR ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA,
WITH THE BEST POTENTIAL ACROSS SOUTHERN NEW JERSEY AND SOUTHERN
DELMARVA.

HIGHS ON FRIDAY WILL DEPEND ON HOW MUCH SUNSHINE WE GET, WITH
CLOUDY AREAS LIKELY BEING CLOSER TO THE COOLER MET GUIDANCE AND
SUNNIER AREAS CLOSER TO THE WARMER MAV GUIDANCE. FOR NOW, WE TOOK
A BLEND OF THE MAV/MET/MOS GUIDE FOR DAYTIME HIGHS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE CENTERED JUST EAST OF NEW ENGLAND WILL
PROVIDE NICE WEATHER THROUGH SATURDAY. FRIDAY NIGHT WILL FEATURE
CLEAR SKIES AND COOL TEMPERATURES FOR THIS TIME OF YEAR, AND AN
EASTERLY FLOW WILL KEEP HIGHS IN THE 80S ON SATURDAY. CONDITIONS
WILL BEGIN TO DETERIORATE SOMEWHAT ON SUNDAY AS A FRONTAL BOUNDARY
APPROACHES FROM THE WEST. CLOUDS WILL BE ON THE INCREASE AND
SHOWERS AND THUNDERSTORM ACTIVITY WILL BECOME INCREASINGLY LIKELY
FROM WEST TO EAST AS THE DAY WEARS ON. THESE CLOUDS SHOULD KEEP
THE HIGH TEMPERATURES ON SUNDAY ONE OR TWO DEGREES COOLER THAN
SATURDAY.

AN ANOMALOUSLY STRONG NRN STREAM CLOSED LOW IS FORECAST TO DIVE
SOUTHWARD FROM NEAR HUDSON BAY INTO THE UPPER MIDWEST EARLY NEXT
WEEK, SETTING UP A RATHER UNUSUAL PATTERN FOR THIS TIME OF YEAR.
THE MID-ATLANTIC REGION WILL BE SITUATED IN AN INCREASINGLY
DIFFLUENT FLOW PATTERN ALOFT ON THE SOUTHEASTERN PERIPHERY OF THE
AMPLIFYING UPPER TROUGH AND ON THE WESTERN PERIPHERY OF THE
WESTERN ATLANTIC RIDGE. THE HEAT AND HUMIDITY WILL RETURN MONDAY
AND TUESDAY DURING THIS TIME AS STRENGTHENING SOUTHWESTERLY FLOW
AHEAD OF THE LOW BECOMES ESTABLISHED OVER THE EASTERN CONUS. MAX
TEMPS IN THE LOWER 90S APPEAR LIKELY MONDAY AND TUESDAY. LEANED
TOWARD THE SLOWER ECMWF SOLUTION REGARDING THE ARRIVAL OF THE
FROPA ON TUESDAY. RAISED MAX TEMPS A FEW DEGREES FROM 12Z WPC
GUIDANCE AS A SLOWER SOLUTION WOULD KEEP THE PRE-FRONTAL WARM
AIR MASS THAT IS CHARACTERIZED BY 850 MB TEMPS NEAR 20C OVER THE
AREA INTO TUESDAY. MAX TEMPS IN THE LOWER 90S OVER THE COASTAL
MID-ATLANTIC REGION FOR ONE MORE DAY.

MONDAY AND TUESDAY BOTH LOOK TO BE A RATHER STORMY PERIOD FOR THE
AREA. THE FOCUS FOR CONVECTION APPEARS TO BE A PRE-FRONTAL/LEE
TROUGH ON MONDAY AND THE MAIN COLD FRONT FOR TUESDAY. FAVORABLE
DYNAMICS IN THE RIGHT ENTRANCE REGION OF AN UNSEASONABLY STRONG
UPPER-LEVEL JET STREAK AND AHEAD OF THE APPROACHING LONG WAVE
TROUGH ALSO LOOKS TO CONTRIBUTE TO SYNOPTIC LIFT OVER THE AREA ON
TUESDAY. THERE ARE STILL PLENTY OF DETAILS THAT NEED TO BE WORKED
OUT THIS FAR OUT, BUT THE POTENTIAL IS THERE FOR SEVERE
THUNDERSTORM EVENTS BOTH DAYS. SPC HAS DEPICTED THE AREA IN A DAY
6 SLIGHT RISK FOR TUESDAY.

COLD FROPA LIKELY TUESDAY NIGHT OR EARLY WEDNESDAY. MUCH COOLER
AND DRIER CONDITIONS ARE FORECAST TO RETURN BEHIND THE COLD FRONT
BY WEDNESDAY. THE 12Z ECMWF INDICATES H8 TEMPS DROPPING INTO THE
SINGLE DIGITS BEHIND THE FRONT.

&&

.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

PRECIPITATION IS MENTIONED IN THE TAFS FOR KPNE, KPHL AND KILG
UNTIL 0600Z.

OVERNIGHT, PRIMARILY VFR CONDITIONS WITH SOME MVFR VISIBILITY
RESTRICTIONS AT SMALLER AIRPORTS AND TERMINALS. WINDS WILL BE
LIGHT. AT THE COASTAL TERMINALS (KACY AND KMIV), WE WILL CONTINUE
THE IFR CIG WITH SOME MVFR VSBY RESTRICTIONS.

ON FRIDAY VFR CONDITIONS EXPECTED OR WILL BE REACHED (AT THE
COASTAL TERMINALS) AT ALL AIRPORTS DURING THE MORNING. PCPN
CHANCES OVERALL ARE LESS THAN TODAY AND NO MENTION WILL BE MADE.
SOME CUMULUS CLOUDS SHOULD FORM, BUT NOT EXPECTING A VFR CIG.
WINDS WILL BE LIGHT FROM THE EAST AND A BAY AND SEA BREEZE FRONT
SHOULD FORM. NOT SURE IF A VERY SHARP DISCONTINUITY WILL FORM AS
THE GENERAL WIND FIELD SHOULD BE FROM THE EAST.

OUTLOOK...
FRIDAY NIGHT THRU SATURDAY NIGHT...POTENTIAL FOR IFR CIGS WITH
MARINE STRATUS TO IMPACT TERMINALS, PARTICULARLY ACY/MIV, FRIDAY
AND SATURDAY NIGHTS WITH ONSHORE FLOW. OTHERWISE VFR EXPECTED WITH
DRY CONDITIONS.

SUNDAY AND MONDAY...CHANCE FOR SHRA/TSRA BOTH DAYS. BETTER CHANCE
MAY BE MONDAY WITH A WELL-DEFINED SFC TROUGH DEVELOPING OVER THE
EASTERN SEABOARD. LOCAL/BRIEF RESTRICTIONS POSSIBLE.

TUESDAY...BETTER CHANCE FOR SHRA/TSRA TUESDAY AS A COLD FRONT
APPROACHES.

&&

.MARINE...
SUB-ADVISORY CONDITIONS ARE EXPECTED THROUGH TONIGHT AND FRIDAY
WITH A FRONTAL BOUNDARY DRAPED ACROSS THE WATERS. THERE REMAINS A
CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH FRIDAY; EXPECT HIGHER
WINDS AND WAVES NEAR THUNDERSTORMS.

OUTLOOK...
FRIDAY NIGHT THROUGH AND SATURDAY NIGHT...HIPRES BUILDS IN FROM
THE NORTHEAST STATES TO START THE WEEKEND. ONSHORE FLOW WILL BE
LIGHT.

SUNDAY THROUGH TUESDAY...WINDS VEER, BECOMING SOUTHWESTERLY ON
SUNDAY. SOUTHWEST WINDS STRENGTHEN MONDAY BUT SHOULD REMAIN BELOW
SCA LEVELS. GUSTY SOUTHERLY WINDS AHEAD OF A COLD FRONT ON
TUESDAY. MARGINAL SCA POSSIBLE. CHANCE FOR SHRA/TSRA LATE SUNDAY.
BETTER CHANCE ON MONDAY AND TUESDAY.

&&

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

&&

$$

SYNOPSIS...KLEIN
NEAR TERM...IOVINO
SHORT TERM...ROBERTSON
LONG TERM...KLEIN/MIKETTA
AVIATION...GIGI/KLEIN
MARINE...KLEIN/ROBERTSON