Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 211932
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
332 PM EDT THU AUG 21 2014

.SYNOPSIS...
WEAK LOW PRESSURE WILL CROSS THE REGION TONIGHT THROUGH FRIDAY
NIGHT AND THEN MOVE OFF THE COAST SATURDAY. HIGH PRESSURE WILL
BUILD ACROSS THE AREA THIS WEEKEND AND REMAIN IN CONTROL OF THE
WEATHER INTO NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA NEXT
WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THROUGH MIDNIGHT TONIGHT...UNSETTLED WITH POTENTIAL FOR BRIEF
POOR DRAINAGE FLOODING AND SMALL HAIL PRODUCING THUNDERSTORMS
(G35KT)...PARTICULARLY NE PA AND NW NJ...AND THINKING AKIN TO THE
00Z/21 NSSL WRF IN WEAK WAA AHEAD OF THE SFC TROUGH IN CENTRAL PA
WHERE SBLI AT 18Z NEAR -7. EXPLAINING THE AXIS OF THE ONGOING
STORMS AT 1830Z...I CANNOT EASILY DO. IT APPEARS INSTABILITY AND
PROXIMITY TO THE COLD TROUGH ALOFT HAS FOCUSED IN OUR CWA MORE TO
THE NORTH RATHER THAN TO THE SOUTH. PWAT NEAR 1.5 INCHES. MLCAPE
1200J. MARGINAL 0-6KM BULK SHEAR. THE SREF AND GEFS POPS ARE 20-30
PCT HIGHER THAN WHAT WE ARE ISSUING AT 330 PM.

AS NOTED EARLIER: THE 12Z NAM CONTG A THEME OF 2 INCH IN ONE HOUR
TSTMS SOMEWHERE IN E CENTRAL PA INTO CENTRAL NJ THIS EVENING. VIL
NEAR 60 AT 1845Z CENTRAL PA IS EITHER VERIFYING THAT RAIN OR
SUGGESTING LARGE HAIL.

WHILE THE PLACEMENT OF THE NAM SHORT TERM QPF IS POSSIBLY WRONG...THE
IDEA I THINK IS CORRECT. A PTN OF E CENTRAL OR NE PA IN N OR CENTRAL
NJ SHOULD RECEIVE SOME STRONG TSTORMS VERY LATE THIS AFTN OR EVENING.

OTRW CONSIDERABLE HIGH CLOUDINESS DELMARVA AS BLOWOFF CLOUD DEBRIS FROM
THE OHIO VALLEY CONVECTION SPREADS EWD.


AFTER MIDNIGHT...NORMALLY ANY EVENING CONVECTION DIMINISHES BUT
THE ECMWF TRIES TO INCREASE RFALL AFTER 06Z WITH THE SHORT WAVE
MOVING SEWD FROM NYS. JUST VERY UNSURE OF WHAT EXISTS AFTER 06Z
TONIGHT.

PLEASE FOLLOW ANY UPDATED SWOMCD`S SWODY1 AND LOCAL PHI CONVECTIVE
RELATED PRODUCTS ISSUED THIS EVENING.

FCST BASIS: TEMPS/DEWS/WINDS ARE A 50 50 BLEND OF THE 12Z/21
GFS/NAM MOS.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
1000J OF MLCAPE AND SLIGHTLY STRONGER 0-6KM BULK SHEAR CUES INTEREST
IN CONVECTION FRI AFTN. SREF HAS DECENT PROBS FOR SHOWERS...ESPECIALLY
E PA...S NJ AND THE DELMARVA. FOR NOW HAVE PLAYED THE SHOWER AND
TSTM RISK CONSERVATIVELY AND MAINTAINED THE 330 AM THURSDAY FCST
POPS FOR FRIDAY...ABOUT 10 PCT BELOW THE 12Z/21 GFS/NAM MOS BLEND.

IT WILL BE SLIGHTLY COOLER AS THE FLOW TURNS MORE EASTERLY AS THE
SFC LOW CONSOLIDATES TO THE S OF THE DELMARVA.

FCST BASIS: TEMPS/DEWS/WINDS ARE A 50 50 BLEND OF THE 12Z/21
GFS/NAM MOS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
THE AREA WILL CONTINUE TO BE UNDER THE INFLUENCE OF THE WEAK UPPER
LOW AND SFC LOW THU NIGHT AND INTO FRIDAY. SCT SHOWERS AND A FEW
TSTMS WILL BE ACROSS MOST AREAS THU EVENING AND THEN DIMINISH
OVERNIGHT...A COUPLE LEFTOVER SHOWERS WILL DEVELOP SAT MOSTLY ACROSS
THE DELMARVA...SE PA AND SRN NJ. CHC FOR SHOWERS ARE ONLY IN THE CHC
RANGE HOWEVER. A FEW DOWNPOURS ARE STILL POSSIBLE THU NIGHT WITH THE
HIGHER PWATS STILL ACROSS THE SRN AREAS. LOWS THU NIGHT WILL MOSTLY
BE IN THE LOW 60S ACROSS THE NORTH AND MID/UPPER 60S ELSEWHERE.
HIGHS SAT IN THE UPPER 70S/LOW 80S SOUTH AND LOW TO MID 70S NORTH.
DRIER AIR WILL CONTINUE TO PUSH IN FROM NORTH TO SOUTH SAT.

AN UPPER RIDGE BUILDS UP TO THE WEST OF THE AREA THIS WEEKEND AND
THEN ROTATES ACROSS THE AREA EARLY NEXT WEEK. SFC HIGH PRESSURE WILL
MOVE SLOWLY IN TANDEM WITH THE UPPER HIGH. THIS WILL PRODUCE A
PERIOD OF DRY WEATHER FOR OUR REGION. POPS FOR SAT NIGHT THRU NEXT
WEN NIGHT ARE SUB-15PCT RANGE FOR THE ENTIRE AREA. TEMPERATURES WILL
BE A FEW DEGREES BELOW NORMAL SUN/MON...NEAR NORMAL TUE...AND THEN A
BIT ABOVE NORMAL WED/THU. HUMIDITY LEVELS WILL BE COMFORTABLE
THROUGH MUCH OF THE PERIOD...BUT WILL TREND UP TOWARD THE MIDDLE
OF NEXT WEEK.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

REMAINDER THIS AFTERNOON...SPOTTY MVFR CIGS IN E PA SHOULD LIFT
THE VFR SCT-BKN AOA 4000 FT ELSEWHERE WITH A LIGHT SOUTHERLY
FLOW. LOCAL IFR CONDS IN SCT SHOWERS AND TSTMS LATE THIS
AFTN...MAINLY VCNTY KRDG AND KABE. A NW WIND GUST TO 35 KT
POSSIBLE ASSOCIATED WITH A LATE AFTN TSTM.

TONIGHT...SCT SHOWERS AND TSTMS THIS EVENING WITH NW WIND G25-35 KT
AND BRIEF IFR CONDS...MAINLY IN THE 23Z-03Z TIME FRAME THOUGH
SHOWERS MAY LINGER LATE AT NIGHT VCNTY KACY. OTRW VFR CIGS MAY
DEGRADE TO MVFR OR IFR CONDS IN ST/FOG TOWARD 09Z. CONFIDENCE ON
DEGRADED CIGS/VSBY LATE AT NIGHT IS BELOW AVG.

FRIDAY...CIGS 2500-4000 FT WITH LOWER IFR CONDS IN SCT SHOWERS AND
TSTMS AND THE WIND TURNING LIGHT EASTERLY.

OUTLOOK...
FRI NIGHT THRU SAT...MOSTLY VFR BUT SCT SHOWERS MAY BRING LOWER CONDITIONS.
SAT NIGHT THRU TUESDAY...VFR EXPECTED.

&&

.MARINE...
SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED THROUGH FRIDAY WITH SEAS
3 FEET OR LESS AND SOUTH TO SOUTHEAST WINDS 5 TO 10 KNOTS BECOMING
EASTERLY FRIDAY.

WE`VE NOT SEEN ANY NEW MAREPS THIS WEEK FROM MARINERS IN OUR EASY
USE (INTERNET AND/OR SMART PHONE) LINK WWW.WEATHER.GOV/PHI/MAROBSFORM
THIS HAS BEEN DERIVED FOR THE MARINER TO EASILY POST INFO INSTANTLY
TO THE NWS FOR USE IN OUR MARINE PRODUCTS.

OUTLOOK...
THU NIGHT THRU FRI NIGHT...SUB SCA CONDITIONS WITH SCT SHOWERS.

SAT AND SAT NIGHT...LOW END SCA CONDITIONS EXPECTED ON THE OCEAN.
FAIR WEATHER.

SUN THRU TUE...SUB-SCA CONDITIONS WITH FAIR WEATHER.

&&

.CLIMATE...
WE RCD INQUIRY ON HOW THE CLIMATE PROGRAM SELECTS FOR OUR 530 PM
CLI. OUR PROGRAM SEARCHES MAX/MIN TEMP DATA FOR THE DAY ENDING 5PM
SHARP. THAT DATA IS INGESTED INTO THE 530 PM POSTED CLI. IF A MAX
TEMP OCCURS THEREAFTER...IT IS REFLECTED IN THE END OF DAY SUMMARY
POSTS AROUND 230 AM EDT THE NEXT DAY AND ALSO YOU CAN CHECK THE 8
PM RTPPHI WHICH POSTS AROUND 815 PM EDT.

&&

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

&&

$$
SYNOPSIS...O`HARA
NEAR TERM...DRAG
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...DRAG/O`HARA
MARINE...DRAG/O`HARA
CLIMATE...






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