Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KPHI 290515
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
115 AM EDT WED JUL 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFF THE COAST ON WEDNESDAY GIVING WAY TO A
WEAK COLD FRONT PASSAGE ON THURSDAY INTO FRIDAY MORNING. ANOTHER
WEAK FRONT MAY CROSS THE REGION SUNDAY INTO MONDAY FOLLOWED BY A
BRIEF SHOT OF HIGH PRESSURE. AFTER THE RESPITE OF HIGH PRESSURE A
STRONGER COLD FRONT IS EXPECTED TO PASS THROUGH ON TUESDAY.

&&

.NEAR TERM /THROUGH TODAY/...
THE WEAK BOUNDARY HAS TEMPORARILY WASHED OUT AS LESS DEFINED AND
NORTHWARD TO NEAR I-78 EARLY THIS MORNING. A LITTLE FOG WILL FORM
DURING THE PREDAWN HOURS BUT NOT AS EXTENSIVE AS SEEN IN YDYS 9Z-
10Z OBS. THE AREAS WHERE IT RAINED LATE YDY MAY BE MORE PREDISPOSED
TO FOG FORMATION.

AFTER SUNRISE...THE BOUNDARY DRYING BECOMES EVIDENT BY FORENOON
WITH HIGHEST DEWPOINTS AND MLCAPE THIS AFTN (400J) CONFINED TO
THE SOUTHERN PORTION OF OUR DELMARVA FCST AREA WHERE AM CARRYING A
SLIGHT CHC FOR A THUNDERSTORM WITH HEAVY RAIN. PWAT INCREASES TO
1.7 INCHES THERE LATE TODAY.

ELSEWHERE...HOT HOT HOT AND USED THE GFS MAVMOS STRAIGHT UP. SEA
BREEZES WILL EVENTUALLY MITIGATE SOME OF THE PURE HEAT IN DE AND
NJ BUT THIS WILL BE A TOASTY DAY WITH 18C AT 850 AND NEAR RECORD
IN SOME PLACES. PLS SEE THE CLIMATE SECTION FOR THE VULNERABLE
RECORDS.

MAX HI TODAY 98-99F...BASICALLY JUST BELOW URBAN CORRIDOR CRITERIA
OF 100.

SW WINDS THIS AFTN MAY GUST 15 MPH IN A FEW SPOTS WITH SEABREEZES
DEVELOPING ALONG THE COASTS BETWEEN NOON AND 2 PM.

CONFIDENCE: ABOVE AVERAGE.

&&

.SHORT TERM /TONIGHT/...
ANY SHOWERS ON THE DELMARVA SHOULD DISSIPATE BY 00Z.

THEREAFTER...SLY FLOW AND MORE HUMID WITH PATCHY FOG AND STRATUS
FORMING. PWAT INCREASES TO 1.9 INCHES BY MORNING ALONG THE I-95
CORRIDOR. MODELS HAVE A WEAK IB THRUST ACROSS DE AND S NJ
OVERNIGHT WHERE SCT OR ISOLATED HEAVY SHOWERS AND TSTMS MIGHT
DEVELOP.

TEMPS WELL ABOVE NORMAL AND USED A BLEND OF 00Z/29 NAM/GFS MOS
WITH A FAVORING OF THE WARMER AVBL GUIDANCE.

CONFIDENCE: ABOVE AVERAGE EXCEPT BELOW AVG ON CONVECTION FORMING
OVERNIGHT.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
5-WAVE MODEL GUIDANCE SHOWS SOUTHEAST RIDGING GIVING WAY TO A DEVELOPING
TROUGH ACROSS THE NORTHEASTERN HALF OF THE CONUS BY THE WEEKEND. A
FEW IMPULSES WILL TRAVERSE THROUGH THE BASE OF THE TROUGH NEXT
WEEK PROVIDING CHANCES FOR MORE UNSETTLED WEATHER EARLY NEXT WEEK.

THURSDAY...INCREASING MOISTURE FLUX AHEAD OF THE WEAKENING COLD
FRONT MAY BRING IN MORE CLOUD COVER THAN PREVIOUSLY EXPECTED. THERE
COULD BE ENOUGH INSTABILITY ADVECTING IN ALOFT TO SPARK SCATTERED
SHOWERS WITH EMBEDDED THUNDER DURING THE MORNING HOURS, MOSTLY
ACROSS THE SOUTH AND WEST, TO KEEP TEMPERATURES FROM REALLY PEAKING
AS HIGH AS PREVIOUSLY THOUGHT, THOUGH LOW-90S IS NOTHING TO SNEEZE
AT. THERE WILL BE SOME ENHANCED VERTICAL MIXING DURING THE AFTERNOON
WHICH SHOULD KEEP DEWPOINTS FROM STAYING IN THE LOW-70S, SO
EXPECTING THEM TO MIX OUT INTO THE UPPER-60S...SHOULD KEEP HEAT
INDEX VALUES JUST BELOW ADVISORY CRITERIA BUT STILL HAVE SOME TIME
FOR FURTHER ASSESSMENT. BESIDES THE HEAT, THE APPROACH OF THE COLD
FRONT LATER IN THE AFTERNOON, WILL TRIGGER MORE SCATTERED SHOWERS
AND THUNDERSTORMS. INSTABILITY IS PREVALENT BUT SHEAR IS ON THE
WEAKER SIDE AS OF NOW BUT DEPENDING ON THE SHEAR AXIS ORIENTATION
TO THE STORMS, WE COULD SEE CELL MERGER OCCUR FORMING A BROKEN
LINE OF STORMS WITH STRONGER WINDS THE MAIN ISSUE. PWATS APPROACH
AND COULD SURPASS 2" SO HEAVY EFFICIENT RAINERS IS ALSO LIKELY
WITH POOR DRAINAGE AND SPOTTY FLASH FLOOD ISSUES POSSIBLE.

FRIDAY - SUNDAY...AS MID-LEVEL TROUGHING BEGINS TO STRENGTHEN BY THE
WEEKEND, THE AFOREMENTIONED FRONT BECOMES MORE PARALLEL TO THE UPPER-
LEVEL FLOW...IT LOOKS TO STALL OFFSHORE. IT BEGINS TO SLOW ITS
DEPARTURE EARLY ON FRIDAY SO THERE COULD BE SOME LINGERING SHOWERS
AND THUNDERSTORMS FRIDAY MORNING BEFORE DRYING OUT. TEMPERATURES
WILL STILL BE QUITE WARM BUT THE FRONT SHOULD BE ABLE TO EAT UP THE
HIGHER DEWPOINTS AS THE AIRMASS DRIES OUT A BIT. WE LOOK TO BE ON
THE SOUTHERN EXTENT OF THE TROUGHING SO MOST OF THE MID-LEVEL ENERGY
STAYS TO OUR NORTH THROUGH THE WEEKEND KEEPING US MOSTLY DRY...COULD
BE SOME ISOLATED SHOWERS ACROSS SOUTHERN DELMARVA CLOSER TO THE
STALLED BOUNDARY. TEMPERATURES ON SATURDAY AND SUNDAY WILL STILL
REMAIN 90+ DEGREES.

MONDAY -  TUESDAY...ANOTHER COLD FRONT IS PROGGED TO PUSH CLOSER TO
THE REGION BY LATE MONDAY INTO TUESDAY. TEMPERATURES AHEAD OF THE
FRONT WILL ONCE AGAIN BE 90+ DEGREES WITH A MOISTENING AIRMASS.
MORE SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE.

&&

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

THROUGH 12Z...VFR WITH POSSIBLE MVFR FOG IN THE 6Z-12Z TIME FRAME.
LIGHT MOSTLY SW WIND.

AFTER 12Z...VFR WITH CLOUDS AOA 6000 FT THIS AFTN. ISOLATED TSTMS
POSSIBLE VCNTY KGED AND KESN MID OR LATE THIS AFTN. SW WIND GUST
NEAR 15 KT THIS AFTN EXCEPT SOUTH SOUTHEAST SEABREEZES DEVELOPING
COASTAL LOCATIONS 16Z-18Z.

TONIGHT....VFR TO START THEN PATCHY MVFR OR IFR CONDS IN FOG/STRATUS/
HAZE LATE, ESPECIALLY NW NJ AND PTNS E PA.

OUTLOOK...
THURSDAY...EARLY MORNING FOG/HAZE WITH MVFR CONDITIONS POSSIBLE...THEN
SCT AFTERNOON/EVENING TSTMS WITH MVFR OR LOWER CONDS.

FRIDAY - SUNDAY...VFR.

&&

.MARINE...
NO HEADLINES THROUGH TONIGHT. A DISTANT OCEAN LOW PRESSURE SYSTEM
SOUTHEAST OF NEW ENGLAND IS PRODUCING A LITTLE MORE SWELL THAN
ANTICIPATED. STILL ATLC SEAS AOB 4 FT THROUGH TONIGHT. SW WINDS
LESS 18KT EARLY THIS MORNING BECOMING SSE THIS AFTN AND SLY
TONIGHT... ALL GUST SPEEDS AOB 22 KT.


OUTLOOK...
THURSDAY - SUNDAY...SUB-SCA CONDITIONS EXPECTED THIS PERIOD.
THUNDERSTORM CHANCES INCREASE ON THURSDAY WITH VERY HEAVY RAINFALL
AND STRONG WIND GUSTS POSSIBLE.

&&

.RIP CURRENTS...
THERE IS A MODERATE RISK FOR THE DEVELOPMENT OF DANGEROUS RIP
CURRENTS ALONG THE NEW JERSEY AND DELAWARE COAST TODAY DUE TO A
LONG PERIOD SOUTHEASTERLY SWELL. THE WAVE PERIOD WILL CONTINUE TO
BE AROUND 10 SECONDS.

&&

.CLIMATE...
KACY RAINFALL 6.58 RANKED 14TH WETTEST NOW WITH THE POR DATING
BACK THROUGH 1874. WETTEST 13.09 IN 1959.

KABE WILL PROBABLY EXPERIENCE NEAR RECORD WARMTH THIS AFTERNOON-JULY
29. THE RECORD THERE IS 96 SET IN 1954. RIGHT NOW WE`RE FCSTG 95.

KRDG AND KMPO MAY BE THE OTHER LOCATIONS WITHIN 2F OF THE RECORD
FOR THIS DATE

KRDG - 97 SET BACK IN 2002.
KMPO - 90 SET BACK IN 1949.

&&

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

&&

$$
SYNOPSIS...HEAVENER
NEAR TERM...DRAG/KLEIN 115A
SHORT TERM...DRAG/IOVINO 115A
LONG TERM...HEAVENER
AVIATION...DRAG/IOVINO/HEAVENER/KLEIN 115A
MARINE...DRAG/IOVINO/HEAVENER 115A
RIP CURRENTS...115A
CLIMATE...115A


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.