AP-NJ--PHL-NJ 1st Area Forecast Discussion, NJ

000

FXUS61 KPHI 151440

AFDPHI

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MOUNT HOLLY NJ

1040 AM EDT WED JUL 15 2015

.SYNOPSIS...

LOW PRESSURE WILL MOVE OFFSHORE LATER TODAY. IN ITS WAKE, HIGH

PRESSURE BUILDS IN FOR THE REMAINDER OF THE WORK WEEK. A WARM

FRONT APPROACHES FROM THE WEST THIS WEEKEND AND SLOWLY MOVES TO

THE MID ATLANTIC COAST EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

HEAVIEST RAINFALL HAS SHIFTED FROM THE LEHIGH VALLEY TO SOUTHERN

NJ...W/ LOCALIZED AMOUNTS SINCE THIS MORNING ALREADY APPROACHING

3 INCHES IN SOME LOCATIONS...AND 24-HOUR AMOUNTS OVER 4 INCHES IN

SOME SPOTS. FLASH FLOODING HAS OCCURED IN THESE LOCATIONS...SEE

OUR LOCAL STORM REPORT FOR MORE DETAILS. THROUGH THE AFTERNOON

HOURS...FOCUS FOR HEAVIEST RAINFALL WILL REMAIN ACROSS SOUTHERN

NJ...WHERE THE GREATEST THREAT OF ADDITIONAL FLASH FLOODING WILL

RESIDE.

NEXT CONCERN IS THE POTENTIAL FOR CONVECTION. SPC HAS OUTLOOKED

A MARGINAL RIRK ACROSS THE CWA. THE MOST ROBUST CONVECTION SHOULD

BE CONFINED TO SOUTHERN NJ...WHERE SURFACE FORCING WILL BE CO-

LOCATED WITH BETTER INSTABILITY AND LOW-LEVEL MOISTURE POOLING.

CANNOT RULE OUT ISOLATED SVR WEATHER /DAMAGING WIND GUSTS/...

BUT THE THREAT IS LOW...WITH THE MAIN CONCERN AGAIN BEING FLASH

FLOODING.

UPDATED FORECAST TO ACCOUNT FOR LOWER TEMPS DUE TO CLOUD COVER.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...

DESPITE MID LEVEL DRY AIR ADVECTION, COULD CONTINUE TO SEE LOW

LEVEL STRATUS IN THE WAKE OF THE TROUGH. THUS TEMPERED THE LOWS,

ESPECIALLY ALONG AND EAST OF THE DELAWARE VALLEY WHERE LOW LEVEL

STRATUS IS MORE LIKELY TO ACCOUNT FOR THE CLOUD COVER. THINK THIS

CLOUD COVER, AND WINDS AROUND 10 KT, SHOULD PRECLUDE ANY

WIDESPREAD FOG DEVELOPMENT. THUS...HAVE REMOVED MENTION OF FOG

FROM THE GRIDS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...

FEW CHANGES WERE MADE TO THE LONG TERM TO FOCUS ON CURRENT

CONVECTION.

PREVIOUS LONG TERM DISCUSSION...

HAZARDS: POTENTIAL METRO I-95 HEAT ADVISORY ONE OR TWO OF THE

DAYS BETWEEN SUNDAY-TUESDAY.

500MB: WARM RIDGING DEVELOPS THIS PERIOD WITH A SLIGHT WEAKNESS

OVER THE NE USA. A TROUGH EVENTUALLY DIGS DOWN INTO THE EASTERN

GREAT LAKES AROUND NEXT TUESDAY.

TEMPERATURES: THE MONTH OF JULY THROUGH THE 13TH IS BASICALLY

NEAR NORMAL AND THE OUTLOOK IS FOR TEMPERATURES TO AVERAGE 3

DEGREES BELOW NORMAL THURSDAY AND POSSIBLY FRIDAY BEFORE WARMING

TO 5 OR MORE DEGREES ABOVE NORMAL SUNDAY-TUESDAY.

FORECAST BASIS: UNLESS OTHERWISE NOTED, A 50 50 BLEND 12Z/14 GFS/NAM

MOS GUIDANCE WEDNESDAY NIGHT-THURSDAY NIGHT, 12Z/14 MEX MOS

FRIDAY AND FRIDAY NIGHT, THEN THE 1521Z/14 WPC GRIDDED ELEMENTS

OF MAX/MIN TEMP, 12 HOUR POP, 6 HOUR DEWPOINT- SKY-WIND FROM

SATURDAY THROUGH NEXT TUESDAY.

THE DAILIES BELOW...

THURSDAY...PWAT DRIES OUT FURTHER TO 0.75 INCH. A NICE

DAY...PLENTY OF SUNSHINE. COOLER. NE WIND GUST 20 MPH DURING THE

MORNING. CONFIDENCE: ABOVE AVERAGE.

FRIDAY...ANOTHER NICE DAY WITH A LIGHT S-SE WIND. CONFIDENCE:

ABOVE AVERAGE.

HEAT WAVE MAY BEGIN IN PLACES ALONG I-95 SATURDAY AND LINGER THROUGH

TUESDAY. CONVECTION AND ASSOCIATED DEBRIS COULD BREAK THIS UP ANY

ONE OF THESE DAYS BUT OVERALL THIS 4 DAY PERIOD LOOKS HOT AND

HUMID WITH SOME CONVECTIVE POTENCY IN A RING OF FIRE PATTERN ALONG

THE PERIPHERY OF THE SOUTHERN STATES RIDGE ALOFT. BETTER INSTABILITY

TENDS TO BE BANKED UPSTREAM MOST OF THIS PERIOD. EML IS DIFFUSED

BY CONVECTION AS IT DEPARTS THE GREAT LAKES ESEWD BUT STILL WORTH

FOLLOWING FOR POTENTIAL CONVECTIVE ENHANCEMENT HERE. ALSO NOTICING

CAPPING 700MB TEMPS OF 11C TRYING TO HEAD EAST LATE IN THE

WEEKEND.

SATURDAY...1000J+ MLCAPE MODELED E PA WITH 25-35 KT 0-6KM BULK

SHEAR, A DIFFERENTIAL WAA PATTERN IN OVERALL NW FLOW WITH A SW

SURFACE WIND GUSTING 15 MPH MAY YIELD SCATTERED STRONG TSTMS I-95

WESTWARD IN A NW FLOW. NOTING DECENT MID LVL LAPSE RATES OF NEARLY

7C/KM WITH REMNANT EML POCKETS SIFTING SEWD INTO OUR AREA.

CONFIDENCE: AVERAGE.

SUNDAY...2200J+ ML CAPE PART OF THE FORECAST AREA. NO 0-6KM BULK

SHEAR TO SPEAK OF. LIGHT SOUTHWEST SFC WIND WITH GENERAL NW FLOW

ALOFT. MID LVL INSTABILITY CONTINUES SIGNIFICANT. COULD BE ONE OF

THOSE BIG CAPE DAYS DRIVING SVR WX PRODUCTION. CONFIDENCE:

AVERAGE.

MONDAY...1500+J ML CAPE MOST OF THE AREA. DIFFERENTIAL WAA. 0-6KM

BULK SHEAR UNDER 25 KT. CONFIDENCE: AVERAGE.

TUESDAY...PROBABLY STILL HOT AND HUMID AHEAD OF WHATEVER TROUGH

DEVELOPS DOWN INTO THE GREAT LAKES. A CFP COULD GENERATE STRONG

TSTMS? CONFIDENCE: AVERAGE.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...

THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,

KILG, KMIV, KACY AND SURROUNDING AREAS.

MOSTLY VFR CONDITIONS THIS AFTN WITH THE EXCEPTION OF LOCALIZED

MVFR/IFR CONDITIONS WITH ANY SHRA OR TSRA. IT LOOKS LIKE KMIV AND

KACY WILL HAVE THE HIGHEST RISK OF MVFR/IFR.

AFTER 00Z, EXPECT MOSTLY VFR CONDITIONS. HOWEVER, EXPECT A STRATUS

DECK TO DEVELOP AND PERSIST FOR MUCH OF THE NIGHT, BUT CURRENT TIME

HEIGHT DISPLAYS OF MODELS DEPICT THIS CLOUD DECK TO BE 4000 TO 6000

FT AGL. THUS...EXPECT MOSTLY VFR CONDITIONS OVERNIGHT.

OUTLOOK...

THURSDAY-FRIDAY...VFR WITH A NNE WIND GUSTY 15-20 KT THU MORNING

DIMINISHING BY THU EVENING AND THEN BECOMING S OR SE FRIDAY BUT

GUSTS UNDER 15 KT. CONFIDENCE: ABOVE AVG.

SATURDAY AND SUNDAY...MOSTLY VFR, BUT MVFR IS POSSIBLE WITH ANY

SHRA OR TSRA AND ALSO POSSIBLE FOR A FEW HOURS SAT NIGHT IN FOG.

CONFIDENCE: AVG.

&&

.MARINE...

SEAS AND WINDS ON THE ATLANTIC SHOULD CONTINUE TO BUILD THROUGH

THE DAY, AND SCA CONDITIONS APPEAR LIKELY BY TONIGHT. THUS THE

SMALL CRAFT ADVISORY CONTINUES FOR THE ATLANTIC WATERS TONIGHT

INTO THURSDAY.

GUSTY WINDS ARE ALSO POSSIBLE WITH ANY THUNDERSTORMS TODAY.

OUTLOOK...

THURSDAY...SCA ISSUED FOR THE ATLC CW WHERE NE GUSTY WINDS 25 KT

FOR A TIME AND FETCH DEVELOPS HAZARDOUS SCA CONDITIONS FM N TO S

WEDNESDAY NIGHT.

THURSDAY NIGHT AND FRIDAY...LEFTOVER 4 FT NE SWELL WITH A 7 TO 8

SECOND PERIOD AND POSSIBLY LINGERING SCA FOR THE DE WATERS THU

NIGHT. OTRW GRADUAL IMPROVEMENT.

WEEKEND...WINDS AND SEAS REMAIN BELOW SCA CRITERIA.

&&

.TIDES/COASTAL FLOODING...

WITH THE NEW MOON TOMORROW, EXPECT TO SEE A COUPLE OF ABOVE

NORMAL HIGH TIDE CYCLES. FIRST, WITH LIMITED ON SHORE FLOW OVER

THE NEXT 24 HOURS, THE HIGH TIDE CYCLE LATER TODAY SHOULD BE JUST

BELOW MINOR FLOODING THRESHOLDS. WINDS WILL SHIFT NORTH-NORTHEAST

BY EARLY THURSDAY RESULTING IN A STRONGER ON SHORE COMPONENT. AS

SUCH, THE HIGH TIDE ON THURSDAY EVENING/EARLY FRIDAY MORNING, MAY

BE RIGHT AT MINOR FLOODING THRESHOLDS FOR THE DE WATERS. THERE

REMAINS SOME UNCERTAINTY WITH THE WINDS, AND THUS THE TIDE

GUIDANCE, SO WILL CONTINUE TO WATCH THIS PERIOD CLOSELY.

&&

.RIP CURRENTS...

WATER TEMPS CONTINUE ABOUT 5F WARMER THAN NORMAL.

WEDNESDAY...LOW RISK AGAIN WITH A 4 FT 8 SECOND SWELL BUT A LIGHT

WEST TO NORTH WIND THAT PERMITS HEATING TO THE COAST BEFORE AN

AFTERNOON SEA BREEZE DEVELOPS. SCT HEAVY TSTMS...SLOW MOVERS AND

TENDING TO MOVE ESE.

THU...DRY AND NICE. 5 FT 6 SECOND NE SWELL WITH A NNE WIND 10-20

MPH. ENHANCED LOW RISK, POSSIBLE MDT RISK.

FRI...DRY AND VERY NICE. SE ONSHORE WIND 10 MPH. 4 FT 7 SECOND.

STILL SLIGHTLY ENHANCED LOW RISK DUE TO THE RESIDUAL NE SWELL.

&&

.EQUIPMENT...

KILG WILL NOT BE TRANSMITTING DATA 13Z-16Z/15 FOR TELCO

MAINTENANCE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...

PA...NONE.

NJ...NONE.

DE...NONE.

MD...NONE.

MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT

THURSDAY FOR ANZ450>453.

SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 8 PM EDT

THURSDAY FOR ANZ454-455.

&&

$$

SYNOPSIS...FRANCK/JOHNSON

NEAR TERM...FRANCK/JOHNSON

SHORT TERM...JOHNSON

LONG TERM...DRAG

AVIATION...DRAG/FRANCK/JOHNSON

MARINE...DRAG/JOHNSON

TIDES/COASTAL FLOODING...

RIP CURRENTS...

EQUIPMENT...

Delivered by Weather Underground Inc. Wed Jul 15 2015 10:41AM EDT