Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 190823
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
423 AM EDT TUE AUG 19 2014

.SYNOPSIS...
QUASI-STATIONARY FRONTAL BOUNDARY TO THE SOUTH OF THE REGION WILL
SLOWLY SLIP FARTHER SOUTH THIS WEEK AS SEVERAL WAVES OF LOW PRESSURE
MOVE EASTWARD ALONG IT. NEW ENGLAND HIGH PRESSURE NOSES IN OVER THE
WEEKEND AND REMAINS NEARLY STATIONARY THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 1008 MB LOW WAS ANALYZED NEAR THE VA-NC BORDER AT 07Z. THE TRACK
OF LOW HAS BEEN A TAD FARTHER SOUTH AND FASTER THAN PREVIOUS MODEL
GUIDANCE HAD PROGGED. THUS, THE BULK OF THE PRECIP WITH THE LOW HAS
STAYED SOUTH OF DE AND EASTERN MD. CUT BACK ON POPS FURTHER BUT KEPT
ISO SHOWERS IN FOR THE MORNING OVER SOUTHERN DE AND ADJACENT MD.

NORTHERN FRINGE OF CLOUDS FROM THIS SYSTEM HAS BEEN HARD PRESSED TO
ADVANCE NORTH OF PHILADELPHIA OVERNIGHT. EXPECT THIS TO CONTINUE
THROUGH MID MORNING WITH SKY COVER RANGING FROM OVERCAST IN FAR
SOUTHERN NJ AND THE DELMARVA TO FEW IN NORTHERN NJ BEFORE DRIER AIR
MOVES IN BEHIND THE SYSTEM AND CLOUDS ERODE. THE ONE EXCEPTION TO
THE CLOUD COVER WILL BE OUT TOWARD MQS-RDG-MPO. THESE LOCATIONS ARE
POSITIONED NEAR OR JUST WEST OF H8 RIDGE AXIS, WHERE BACKING WINDS
OUT OF THE SOUTH WILL RESULT IN WEAK ISENTROPIC LIFT AND CLOUDS. AN
ISO SHOWER MAY DEVELOP ACROSS THE HIGHER TERRAIN OF PA LATE IN THE
AFTERNOON, BUT MOST OF THIS ACTIVITY SHOULD BE FOCUSED DEEPER WITHIN
LLVL THETA-E RIDGE, WHICH WILL BE SITUATED WEST OF THE CWA.

USED A BLEND OF MAV/MET GUIDANCE FOR MAX TEMPS TODAY BUT WITH
ONSHORE FLOW DEVELOPING, UNDERCUT TEMPS A COUPLE OF DEGREES NEAR THE
COAST. TEMPS TODAY WILL BE SLIGHTLY BELOW NORMAL, WHICH FITS THE
PATTERN ACROSS THE REGION FOR MUCH OF THE MONTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
WEAK HIGH PRESSURE OVER NEW ENGLAND WILL START TO NOSE DOWN TOWARD
THE NORTHERN MID-ATLANTIC REGION TONIGHT AS LOW PRESSURE MOVES
FARTHER OFF THE NC COAST. MOST OF THE FORECAST AREA SHOULD BE ABLE
TO CLEAR OUT EXCEPT IN THE FAR WEST. WILL ALSO NEED TO WATCH FOR THE
POTENTIAL FOR THE DEVELOPMENT OF LOW CLOUDS/FOG LATE TONIGHT IN
COASTAL NJ/DE WITH A PERSISTENT ONSHORE FLOW. MIN TEMPS RANGE FROM
THE UPPER 50S IN THE POCONOS TO MID 60S NEAR THE COAST AND IN THE
URBAN I-95 CORRIDOR.

&&

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
HEMISPHERIC PATTERN SHOWS RIDGING OFF THE EAST COAST WITH A CLOSED
LOW FEATURE OVER THE CANADIAN MARITIMES. WEAK MID-LEVEL RIDGING OVER
THE GREAT LAKES WITH A MEANDERING CUT-OFF LOW OVER THE UPPER
MID-WEST SLOWLY MOVES EASTWARD WITH TIME AND BECOMES ABSORBED BY THE
OPENING OF THE CLOSED LOW OVER THE CANADIAN MARITIMES BY THE
WEEKEND. RIDGING MOVES OVERHEAD BY LATE THIS WEEKEND INTO NEXT WEEK.

WEDNESDAY...THE 00Z GUIDANCE HAS COME IN A BIT FASTER THAN THE 12Z
WITH THE SHORTWAVE ENERGY MOVING ACROSS THE REGION AND THE
ASSOCIATED SURFACE BOUNDARY. THAT BEING SAID, THE GUIDANCE STILL
KEEPS THE BETTER CHANCES FOR SHOWERS UNTIL THE OVERNIGHT TIMEFRAME
AND MOSTLY ACROSS OUR WESTERN ZONES...EASTERLY UPSLOPE FLOW WILL
HELP INCREASE CHANCES LATE.

THURSDAY - FRIDAY...INCREASING CHANCES FOR SCATTERED SHOWERS AS THE
SHORTWAVE MOVES DIRECTLY OVERHEAD ON THURSDAY...LOOKS LIKE THE
WETTEST DAY OF THE LONGTERM. MODEST SURFACE BASED CAPE OF 1000J/KG,
SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING LOW, COMBINED WITH COLD
POOL ALOFT AND STEEPER MID-LEVEL LAPSE RATES, SHOULD BE ENOUGH FOR
SCATTERED CONVECTION TO OCCUR...PRIMARILY DIURNALLY DRIVEN. SLOWER
MOVEMENT OF THE OPENING MID-LEVEL LOW COULD KEEP SHOWERS AROUND,
MOSTLY ACROSS THE SOUTHERN HALF, THROUGH THE FIRST PART OF FRIDAY
BEFORE CLEARING OUT.

SATURDAY - SUNDAY...NEW ENGLAND HIGH PRESSURE BETTER ESTABLISHES
ITSELF PUSHING A RIDGE AXIS DOWN THROUGH OUR REGION. PERSISTENT
ONSHORE FLOW SHOULD BE ENOUGH TO KEEP A MAJORITY OF THE REGION
STABLE ENOUGH TO OMIT THUNDER FROM THE FORECAST OVER THE WEEKEND.
MID-LEVEL LOW/TROUGH WILL BE TO THE SOUTHEAST OF THE REGION WITH
MID-LEVEL RIDGING TRYING TO WORK IN FROM THE SOUTHWEST. SURFACE
CONVERGENCE LOOKS TO STAY JUST TO THE WEST OF THE REGION AS MORE
SHORTWAVE ENERGY DIVES SOUTHEAST WITHIN THE CYCLONIC FLOW
ALOFT...RING OF FIRE ACTION IS CLOSE BY. WE KEEP THE FORECAST MOSTLY
DRY AT THIS TIME, BUT CONFIDENCE IS LOWER TO OUR WEST AND SOUTH,
CLOSER TO THE SURFACE BOUNDARY.

MONDAY - TUESDAY...BETTER CHANCE THAT WE WILL BE DRY FOR THE END OF
THE LONGTERM AS THE UPPER LOW MOVES FARTHER TOWARDS THE EAST AND
RIDGING OVERRIDES THE REGION. A COLD FRONT MAY NEAR FROM THE
NORTHWEST SOMETIME ON TUESDAY.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

BKN-OVC CLOUDS ASSOCIATED WITH LOPRES IN THE SRN MID ATLANTIC WILL
IMPACT TERMINALS FROM PHL SOUTH THIS MRNG, BUT WILL BE IN VFR CAT.
NO FLIGHT RESTRICTIONS EXPECTED THIS AFTN AND EVE. EASTERLY FLOW
5-10 KT WILL DEVELOP TODAY. THERE IS STILL A POTENTIAL FOR LOW
CLOUDS AND/OR FOG TO DEVELOP NEAR ACY/MIV AFTER 06Z TONIGHT UNDER
THE INFLUENCE OF ONSHORE FLOW.

OUTLOOK...
WEDNESDAY...CHANCE OF SOME MVFR CIGS SERN AIRPORTS AND TERMINALS
WED MORNING. CONFIDENCE NOT HIGH. PRIMARILY VFR ELSEWHERE.

WEDNESDAY NIGHT - THURSDAY NIGHT...CHANCE FOR SHRA/TSRA AS A SERIES
OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY FLIGHT MVFR
RESTRICTIONS POSSIBLE.

FRIDAY THROUGH SATURDAY...PREDOMINATELY VFR CONDITIONS.

&&

.MARINE...
THE PRESSURE GRADIENT BETWEEN WEAK HIPRES OVER NEW ENGLAND AND
LOPRES MOVING OFF THE VA-NC COAST WILL TIGHTEN TODAY. EASTERLY WINDS
WILL STRENGTHEN AS A RESULT LATER THIS MORNING AND AFTERNOON. THE
STRONGEST WINDS WILL BE IN THE COASTAL DE WATERS, WHERE WINDS
INCREASE TO AROUND 15-20 KT. WINDS GRADUALLY SUBSIDE TONIGHT AS THE
LOW PULLS AWAY.

OUTLOOK...
WEDNESDAY - THURSDAY...ONSHORE FLOW CONTINUES BUT WILL
WEAKEN OVER TIME. TSRA POSSIBLE IN SOUTHERN WATERS ON THURSDAY.

FRIDAY - SATURDAY...SUB SMALL CRAFT ADVISORY WINDS
EXPECTED. THE PERSISTENT ONSHORE FLOW MIGHT BRING SEAS TO SMALL
CRAFT ADVISORY LEVELS FRIDAY AND POSSIBLY MORE LIKELY ON SATURDAY.

&&

.RIP CURRENTS...
EASTERLY FLOW CONTINUES TO STRENGTHEN THIS MORNING AND 10 SECOND
SWELLS HAVE BEEN REPORTED FROM BUOY 44009. THESE CONDITIONS WILL
PRODUCE A MODERATE RISK OF RIP CURRENTS FOR THE NEW JERSEY BEACHES
AND LOW FOR DELAWARE BEACHES TODAY.

&&

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

&&

$$
SYNOPSIS...HEAVENER
NEAR TERM...KLEIN
SHORT TERM...KLEIN
LONG TERM...HEAVENER
AVIATION...GIGI/HEAVENER/KLEIN
MARINE...GIGI/HEAVENER/KLEIN
RIP CURRENTS...KLEIN





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