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000
FXUS61 KPHI 212208
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
608 PM EDT TUE MAY 21 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEASTERN UNITED STATES
COAST THROUGH THURSDAY. AN AREA OF LOW PRESSURE WILL MOVE FROM THE
SOUTHERN PLAINS TO SOUTHEASTERN CANADA THROUGH THURSDAY AND BRING
A COLD FRONT THROUGH THE REGION LATE THURSDAY INTO FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST FOR THE HOLIDAY WEEKEND
THIS HIGH WILL THEN GRADUALLY MOVE OFFSHORE THROUGH TUESDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
ESTF UPDATE AT 550 PM.

STARTED THE EVENING MOSTLY CLEAR AND CUT OUT THE CHANCE OF SHOWERS
AND TSTMS PRIOR TO MIDNIGHT. THE ACTION IN MONROE AND SUSSEX
COUNTIES AROUND 2PM WAS ALL THAT WE WOULD HAVE TODAY.

THERE IS A SMALL CHANCE THAT ISOLATED CONVECTION NOW FORMING IN
FAR NORTH CENTRAL PA WILL TURN ESE AND INVADE THE POCONOS AROUND
11 PM BUT FOR NOW...MODEL SIGNALS ARE DRY FOR THIS EVENING AND
WITHOUT CU...ITS DIFFICULT TO HAVE A SHOWER.

THE FOG WAS DELAYED TIL LATER AND ATTM...NOT CALLING IT 1/4MI DENSE.
WILL REREVIEW FOG POTENTIAL LATER THIS EVENING.

LOW OVC WITH AREAS OF FOG SHOULD TEND TO BECOME WIDESPREAD AFTER
06Z. CONDITIONS WILL PROBABLY REMAIN ABOVE DENSE FOG ADVISORY
CRITERIA...SO WE HAVE NOT ISSUED. IT WILL REMAIN WARM AND HUMID
AGAIN TONIGHT WITH LOWS IN THE LOW/MID 60S NORTH AND MID/UPPER 60S
SOUTH. WINDS LIGHT MOSTLY FROM THE SW.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/...
WEDNESDAY WILL HAVE WEATHER SIMILAR TO TODAY. PLENTY OF CLOUDS/FOG IN
THE MORNING AND THE CHC FOR SHOWERS/TSTMS DURING THE AFTERNOON. THIS
ACTIVITY WILL PROBABLY BE FOUND ACROSS MOST AREAS...UNLIKE TDY WHERE
IT WAS RESTRICTED TO THE NORTH. WE WILL CARRY POPS IN THE CHC RANGE
FOR NOW. THE SPC HAS PLACED THE SLGT RISK FOR TSTMS TO THE WEST OF
OUR AREA...SO WE WILL WATCH FOR UPDATED OVERNIGHT. HIGHS WILL BE
VERY WARM AGAIN WED WITH TEMPS IN THE MID 80S IN MOST AREAS (EXCEPT
ALONG THE SHORE...WHERE READINGS IN THE UPPER 70S TO LOW 80S MAY
OCCUR).

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE AREA OF HIGH PRESSURE WILL REMAIN OFF THE ATLC CST WED NIGHT
AND THU AND SWLY FLOW WILL CONTINUE WHICH WILL KEEP WARM WX OVER
THE AREA. HOWEVER, BY THU, AN AREA OF LOW PRESSURE WILL MOVE INTO
SERN CANADA. THE CDFNT ASSOCD WITH THIS LOW WILL CROSS THE REGION
THU NIGHT. THIS PD LOOKS TO TO BE THE WETTEST WITH SHOWERS, TSTMS
AND PSBLY SOME HEAVY RAIN. ITS A BIT TOO EARLY TO BE CERTAIN ABOUT
ANY SEVER WX POTENTIAL. IT WILL BE DEPENDENT ON DAYTIME HEATING
AND OTHER FACTORS. HOWEVER, IT COULD BE MITIGATED BY THE FACT THAT
THE FRONT WILL BE COMING THROUGH AFTER SUNSET. THE 21/12Z GFS IS
THE SLOWEST MDL CLEARING THINGS OUT ON FRI AND TRIES TO DEVELOP A
WAVE ALG THE FRONT. NONE OF THE OTHER MDLS HAVE THIS FEATURE, SO
AM NOT INCLINED TO GO ALONG FOR NOW. FRI, ESPECIALLY LATER FRI,
SHOULD SEE IMPROVING WX AND BY SAT A LARGE AREA OF HIGH PRESSURE
WILL PUSH INTO THE MIDWEST FROM CANADA WAND WILL SLOWLY SLIDE EWD
THRU THE HOLIDAY WEEKEND.

THE PGRAD BETWEEN THE BUILDING HIGH AND THE DEPARTING LOW OVER THE
CANADIAN MARITIMES WILL KEEP A DECENT NWLY FLOW OVER THE AREA ON
SAT, WITH WEAKENING FLOW AS THE HIGH MOVES IN ON SUN. SO, AT THIS
POINT, THE WEEKEND LOOKS PREDOMINANTLY DRY, ALBEIT COOL FOR LATE
MAY AND WITH A BRISK NW WIND, IT WILL FEEL COOLER ON SAT.

TEMPS LOOK TO BE WARMEST ON THU, WITH TEMPS AROUND 80 OR INTO THE
80S. THEN BEHIND THE FRONT MOST LOCATIONS WILL BE AROUND 70 OR
INTO THE LOWER 70S FOR THE REMAINDER OF THE PD. SAT LOOKS TO BE
THE COOLEST DAYS, WITH MANY LOCATIONS HOVERING IN THE MID/UPPER 60S.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...VFR CIRRUS WITH PATCHY SC VCNTY KACY-KMIV THIS EVENING.
LIGHT SSW WIND. CONDITIONS LIKELY TO BECOME IFR OR LIFR IN ST/FOG
AFTER 07Z.

WED...AFTER A PROBABLE IFR CONDITION START AT 12Z...A SLOW RETURN TO
VFR BY MID OR LATE MORNING WITH SCT-BKN CLOUDS AOA 3500 FT IN THE
AFTN AND A SHOWER OR TSTM POSSIBLE DURING THE AFTERNOON...MAINLY
VCNTY KRDG OR KABE. SW WIND GUST TO 15 KT IN THE AFTN.


OUTLOOK...
WED NIGHT THROUGH THU NIGHT...MAINLY VFR. MVFR, POSSIBLY IFR,
CONDITIONS POSSIBLE IN ANY SHOWERS AND THUNDERSTORMS OR PDS OF
HEAVY RAIN. WIND WILL SHIFT FROM SW TO NW BEHIND CFP LATE WED
NIGHT/EARLY THU MRNG. HIGH CONFIDENCE ON THE OVERALL DETAILS. LOW
CONFIDENCE ON THE FACT THAT ALL SITES WILL SEE MVFR/IFR AND
TIMING.

FRI...MAINLY VFR WITH A CHANCE OF SHOWERS MAINLY IN THE MORNING.
HIGH CONFIDENCE.

SAT-SUN...VFR CONDITIONS EXPECTED. A BRISK NW WIND ON SAT OF 15-20
KT.  HIGH CONFIDENCE.

&&

.MARINE...
WINDS HAVE BEEN MOSTLY SW/S ACROSS THE WATERS TODAY WITH SPEEDS
MOSTLY 10 TO 15 KTS. SEAS HAVE BEEN MOSTLY AROUND 3 FT ON THE OCEAN
AND 1 TO 2 FT OVER THE DEL BAY. CONDITIONS SHOULD REMAIN SUB-SCA
TONIGHT AND APPROACH SCA LATER WEDNESDAY. WINDS WILL INCREASE
WED...BUT WITH THE WARMER AIR AND COOLER SEAS...THE WINDS/WAVE
GUIDANCE MAY BE TOO HIGH. WE OPT TO KEEP THE SEAS AT 3 TO 4 FT FOR
WED AND HOLD THE WINDS BELOW SCA FLAG LEVELS. A FEW G 20-25 ARE NOT
OUT OF THE QUESTION LATER WED. SCAT SHOWERS/TSTMS EXPECTED WED.

OUTLOOK...
HIGH PRESSURE ANCHORED OFF THE SOUTHEASTERN UNITED STATES COAST WILL
BRING A PROLONGED SOUTH TO SOUTHWEST FLOW FOR WED NIGHT THROUGH
THU. AS THIS FLOW STRENGTHENS WITH A CDFNT APPROACHING FROM THE W
ON THU, WINDS AND SEAS WILL GRADUALLY INCREASE. THEREFORE, SEAS
AND WIND COULD BE AOA SCA CRITERIA BY THE START OF THE OUTLOOK PD. A
SMALL CRAFT ADVISORY MAY BE NEEDED FOR THIS PD ON THE OCEAN FRONT.
HOWEVER, WITH VERY WARM AIR OVER THE RELATIVELY COOL OCEAN AND
WAVE WATCH OVERDOING HEIGHTS OF LATE, HAVE DECIDED NOT TO POST
ANYTHING ATTM. THERE WILL ALSO BE SOME SHWRS/TSTMS WED NIGHT INTO
THU ALG AND AHEAD OF THE CFP.

THE COLD FRONT WILL CROSS THE AREA WATERS LATE THURSDAY INTO FRIDAY.
BOTH WINDS AND SEAS WILL START TO SUBSIDE AND SHOULD FALL BELOW
SCA CRITERIA. WINDS AND SEAS SHOULD REMAIN BELOW CRITERIA THROUGH
THE HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION.

&&

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

&&

$$
SYNOPSIS...NIERENBERG
NEAR TERM...DRAG/O`HARA 607
SHORT TERM...DRAG/O`HARA
LONG TERM...NIERENBERG
AVIATION...DRAG/NIERENBERG/O`HARA 607
MARINE...DRAG/NIERENBERG/O`HARA 607