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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 170746
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
346 AM EDT MON JUN 17 2013

.SYNOPSIS...
-- Changed Discussion --
A LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE NORTHEAST THROUGH THE
SAINT LAWRENCE VALLEY TODAY AND TONIGHT. ITS FIRST WEAKENING COLD
FRONT SHOULD CLEAR THE FORECAST AREA THIS MORNING. THEN ITS
SECONDARY COLD FRONT SHOULD ARRIVE TUESDAY OR TUESDAY NIGHT WITH A
WEAK LOW PRESSURE SYSTEM FORMING ALONG IT. A HIGH PRESSURE SYSTEM
WILL THEN BUILD INTO THE NORTHEAST THE LATTER HALF OF THE WORK WEEK
BEFORE SHIFTING OFFSHORE ON SATURDAY. A WARM FRONT IS FORECAST TO
MOVE THROUGH THE FORECAST AREA ON SUNDAY.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
THE FORECAST AREA WILL HAVE A COLD FRONT TO OUR SOUTH TODAY, ANOTHER
COLD FRONT APPROACHING OUR NORTHERN ZONES, AND A FAIRLY ZONAL FLOW
IN THE MID-LEVELS. THAT SAID, THE MAJORITY OF THE CWA SHOULD BE
PRECIP FREE.

WE`LL START THE DAY OFF WITH JUST SOME SMALL POPS ACROSS THE FAR
SOUTH. IN THE AFTERNOON WE`LL SHIFT THOSE SOUTHERN POPS UP TO ABOUT
WILMINGTON. AT THE SAME TIME, WE`LL ADD SOME POPS TO THE POCONOS AND
NORTHWEST NJ. GFS MAV POPS ARE FAVORED.

CAN`T RULE OUT SOME THUNDER, BUT NOT EXPECTING ANYTHING TO PACK A
GREAT PUNCH. IN FACT, WE`RE NOT EVEN IN SPC`S SEE TEXT.

THE MAJORITY OF TEMPS ARE FORECAST TO BE IN THE MID 80S. THE
EXCEPTION OF COURSE WILL BE ACROSS OUR NORTHWEST ELEVATIONS AND THE
COAST.

WEST TO SOUTHWEST WINDS WILL BE IN THE 5 TO 10 MPH RANGE, MAYBE UP
TO 15 MPH THIS AFTERNOON AT TIMES.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
-- Changed Discussion --
THIS PERIOD STARTS WITH THE NORTHERN FRONT POISED TO ENTER THE
FORECAST AREA WHILE THE MID-LEVELS REMAIN ZONAL. POPS EXPAND AND
INCREASE A BIT IN RESPONSE ACROSS THE NORTHERN 1/3 OF THE CWA.
ACROSS THE SOUTHERN 1/3 OF THE CWA, POPS REMAIN IN PLACE WITH THE
SOUTHERN FRONT JUST TO OUR SOUTH.

SMALL POPS FILL IN THE MIDDLE 1/3 OF THE CWA AFTER 06Z AS THE
NORTHERN FRONT CONTINUES TO DRIFT SOUTH. ONCE AGAIN GFS MAV POPS ARE
FAVORED.

TEMPS WILL FALL BACK IN TO 50S ACROSS THE FAR NORTHWEST AND REMAIN
IN THE 60S ELSEWHERE. SOUTHERN DELAWARE WILL REMAIN CLOSE TO 70.

WINDS WILL BE LIGHT OUT OF THE SOUTHWEST.
-- End Changed Discussion --

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
THE WRF-NMMB INITIALIZATION LOOKED SLIGHTLY BETTER OVERALL AND THE
SOUNDING PROBLEMS AT ALB AND CHH DID NOT APPEAR TO HAVE AN IMPACT.
OVERALL THE MODELING CONSENSUS WAS BETTER THAN LAST NIGHT WITH A
SLIGHT SLOWING TREND WITH THE SECONDARY COLD FRONT. WITH THE OP GFS
AND WRF-NMMB VERY SIMILAR TO EACH OTHER`S ENSEMBLE MEAN, CONFIDENCE
ABOUT THE TIMING IS INCREASING FOR THE HIEST POPS (NOON-MIDN ON
TUE), UNFORTUNATELY, THESE ARE CRIS-CROSSING FCST PERIODS, SO OUR
POPS ARE MORE OF A REFLECTION TO THE UNCERTAINTY OF WHICH FCST
PERIOD, THAN THE OVERALL PROBABILITIES WHICH APPEAR LIKELY.

AS FOR THE DETAILS, THIS IS A TYPICAL SPLIT WE FIND IN OUR CWA WITH
THE FCST HIGHEST CAPES (WRF SOUNDING LLVL DEW POINTS LOOK MORE
REASONABLE THAN THE GFS) SOUTH AND THE BEST WIND FIELD AND FORCING
NORTH AS WELL AS THE ENTRANCE REGION TO THE 250MB JET. THE
FORECAST CONVECTIVE TEMPS ARE EXPECTED TO BE REACHED, BUT NOT TIL
THE AFTERNOON. GIVEN THE EVER SO SLIGHT SLOWING TREND BY THE
MODELS, THE MORNING POP MENTION MAY VERY WELL BE TOO FAST AND EVEN
THE POPS SOUTH MAY HAVE TO RELY ON SEA/BAY BREEZES TO INITIATE.
REGARDLESS WITH ADDITIONAL HEATING EXPECTED AND FCST CAPES GETTING
TO AROUND 1000J, DECENT FCST BULK SHEAR (WIND BELOW 700MB
ADMITTEDLY WEAK) AND DCAPE APPROACHING 1000J WE WILL HAVE TO WATCH
FOR THE FORMATION OF ROBUST THUNDER. SPC SEE TEXT LOOKS GOOD AT
THIS POINT. SOME MESOSCALE MODELS ARE PREDICTING A SQUALL LINE
MOVING THROUGH THE NORTHERN HALF OF OUR CWA BY LATE IN THE DAY
TUESDAY. AS ANYONE THAT FOLLOWS THESE MODELS, THEY CAN BE
FRIGHTENINGLY ACCURATE, BUT THEY HAVE TO GET THE IGNITION SEQUENCE
CLOSE. ALBEIT WITH BETTER LOOKING TIMING, WE DID UP THE POPS AND
WITH PWATS FCST TO STILL REACH 1.5 INCHES, HEAVY DOWNPOURS NOT OUT
OF THE QUESTION EITHER. BECAUSE OF THE SLOWER FRONTAL TIMING, STAT
GUIDANCE HAS BECOME HOTTER WITH MAX TEMPS. NOT GOING THAT HOT YET
BASED ON RECENT WET CONDITIONS, BUT WE BUMPED MAX TEMPS UP BY
AROUND 5F.

WE NUDGED THE AXIS OF HIGHEST POPS SOUTH ON TUESDAY EVENING AND THEN
LOWER POPS OVERNIGHT. USING A GFS AND ECMWF COMPROMISE, WE KEPT THE
MENTION OF THUNDER THRUT ON TUESDAY EVENING AND IN THE SOUTHERN
PART OF OUR CWA THRU THE NIGHT. MIN TEMPS WERE ALSO BUMPED UPWARD
BECAUSE OF THE SLOWER TIMING.

I GUESS IT SHOULD HAVE COME AS NO SURPRISE AS WE GET CLOSER TO
ASTRONOMICAL SUMMER THAT THE COLD FRONTS ARE STRUGGLING TO MOVE
SOUTHWARD. WHILE THE WAVE ON THE FRONT IS FORECAST TO BE WEAKER, THE
LATEST WRINKLE ABOUT EXTENDING POPS INTO WEDNESDAY COMES FROM A
SHORT WAVE TROF INTERACTING WITH A BANKING AND DEVELOPING UPSLOPE
FLOW. WITH THE OCEAN STILL RELATIVELY COOL, THE STABILIZING
INFLUENCE OF THE ONSHORE FLOW IS DEFLECTING SFC (ALOFT TOO) BASED
INSTABILITY WEST OF OUR CWA. WANT TO SEE WHERE THIS GOES BEFORE WE
GET MORE DOUR, BUT FOR NOW WE INTRODUCED LOW POPS. THE ONSHORE
FLOW COUPLED WITH THE 500MB TROF NOT THROUGH SHOULD HELP
GENERATE/PERPETUATE CLOUDINESS, SO WE DID KEEP THE IDEA OF A
CHILLY DAY ALONG THE COAST AND KNOCKED DOWN MAX TEMPS ABOUT 1OF
FROM TUESDAY.

NOT GOING THERE WITH THE WRF-NMMB FOGGING US IN ON WEDNESDAY
NIGHT. THE AIR MASS IS FCST TO BE DRYING, SO HAVE TO SEE THE SFC
HIGH STRUGGLE MORE THAN CURRENTLY PROGGED. DRIER AIR AROUND THE
SFC HIGH EVEN IF WEAK ONSHORE FLOW WILL MAKE FOR A SUNNIER DAY ON
THURSDAY WITH MAX TEMPS STILL SLIGHTLY BELOW NORMAL.

NO BIG CHANGES BEYOND THAT. A DISSIPATING COLD FRONT IS NOT
FORECAST TO BRING ANY PCPN OUR WAY ON FRIDAY AND MIGHT EVEN IN ITS
DEMISE HELP SLOW THE ARRIVAL OF MORE HUMID AIR. THE WARM FRONTAL
PASSAGE (AND POPS) HAS BEEN PUSHED BACK TO LATE SATURDAY AND
SUNDAY. REGARDLESS BY THE FIRST WEEKEND OF ASTRONOMICAL SUMMER,
TEMPERATURES SHOULD BE AT OR ABOVE AVERAGE.
-- End Changed Discussion --

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

VFR AT THE TERMINALS EARLY THIS MORNING WITH THE EXCEPTION OF
MILLVILLE. WE`RE LOOKING AT MVFR HERE WITH SOME FOG. A FEW OTHER
TERMINALS WILL PROBABLY FOLLOW MILLVILLE`S LEAD THE NEXT COUPLE OF
HORUS.

AFTER SUN-UP, ALL TERMINALS GO VFR AND REMAIN THAT WAY THROUGH THE
PERIOD EXCEPT IN SHOWERS. FOR NOW, WE`LL HIT KABE IN THE NORTH WITH
SOME SHOWERS AND KILG, KMIV, AND KILG ACROSS THE SOUTH. NOTHING AT
THE PHILLY TERMINALS, TRENTON, OR READING.

WEST TO SOUTHWEST WINDS WILL MAX OUT THIS AFTERNOON AT ABOUT 10 KT
TODAY AND FALL BACK IN THE 5 TO 10 MPH RANGE TONIGHT.

OUTLOOK...
TUESDAY AND TUESDAY NIGHT...MVFR OR LOWER AT TIMES WITH SHOWERS
AND THUNDERSTORMS. THERE COULD BE SOME MVFR/IFR LATE AT NIGHT DUE
TO SOME FOG.

WEDNESDAY...POCKETS OF MVFR CONDITIONS IN THE MORNING, OTHERWISE
VFR.

WEDNESDAY NIGHT THROUGH FRIDAY...VFR.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
NO HEADLINES WILL BE ISSUED THIS MORNING FOR AREA WATERS.

SOUTHWEST WINDS WILL PEAK IN THE 10 TO 15 MPH RANGE THIS AFTERNOON.
OCEAN WAVES WILL BE IN THE 2 TO 4 FOOT RANGE WITH 1 TO 2 ON DELAWARE
BAY.

NOT MUCH CHANGE TONIGHT EXCEPT WE`LL THROW SOME 20 KT GUSTS INTO THE
FORECAST WITH THE ARRIVAL OF COLD FRONT FROM THE NORTH.

SMALL POPS REMAIN IN THE FORECAST ACROSS THE SOUTH TODAY AND EXPAND
TO INCLUDE THE NORTH TONIGHT.

OUTLOOK...
RIGHT NOW WE ARE NOT OUTLOOKING SCA CONDITIONS TO OCCUR THROUGH
FRIDAY. THE LOW PRESSURE SYSTEM ON THE FRONTAL BOUNDARY IS FORECAST
TO BE WEAKER THAN LAST NIGHT. HOWEVER, THE WAY THE HIGH PRESSURE
SYSTEM IS FORECAST TO BUILD INTO THE AREA WATERS IS NOW BRINGING
MORE OF A NORTHEAST TO EAST FETCH WEDNESDAY INTO THURSDAY. WE WILL
SEE IF THIS NEW DEVELOPMENT HAS STAYING POWER AND WHETHER OR NOT THE
ONSHORE FLOW AND SWELLS GET ENHANCED ENOUGH TO POSSIBLY REACH SCA
CONDITIONS. THEN THE LIKELIHOOD OF SUB SMALL CRAFT ADVISORY
CONDITIONS INCREASES ON FRIDAY AS THE SFC HIGH SETTLES NEARBY.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...GIGI/GORSE
NEAR TERM...KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...GIGI
AVIATION...GIGI/GORSE/KRUZDLO
MARINE...GIGI/KRUZDLO