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000
FXUS61 KPHI 060835
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
335 AM EST FRI DEC 6 2013

.SYNOPSIS...
A COLD FRONTAL MOVE OFF EAST COAST TODAY AND MOVE TO OUR SOUTH OVER
THE WEEKEND AS A SERIES OF LOW PRESSURES MOVE ALONG THE BOUNDARY.
HIGH PRESSURE WILL BRIEFLY BUILD ACROSS THE NORTHEAST SATURDAY NIGHT
INTO SUNDAY. AN AREA OF LOW PRESSURE WILL DEVELOP ACROSS THE LOWER
MISSISSIPPI RIVER VALLEY, THEN STRENGTHEN AS IT MOVES NORTHWARD INTO
THE GREAT LAKES SUNDAY NIGHT. THIS WILL LIFT WARM FRONT ACROSS THE
AREA EARLY MONDAY, FOLLOWED BY A COLD FRONT MONDAY NIGHT. A WEAK
CLIPPER SYSTEM MAY SKIRT ACROSS THE NORTHERN TIER OF THE COUNTRY
EARLY NEXT WEEK BEFORE HIGH PRESSURE BUILDS ACROSS THE REGION LATE
IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE SFC COLD FRONT IS BEGINNING TO ADVANCE ACROSS THE WRN PARTS OF
THE CWA EARLY THIS MORNING. SHOWERS THAT HAVE DEVELOPED AHEAD OF THE
FRONT ARE BEGINNING TO STIR THINGS UP ENOUGH TO BRING VSBYS UP OUT
OF DENSE FOG CRITERIA. A FEW STATIONS MAY STILL BE BELOW ONE-HALF
MILE FOR A LITTLE WHILE...BUT THE TREND SHOULD BE TOWARDS HIGHER
VSBYS SO WE WILL CANCEL THE ADVISORY WITH THE AM PACKAGE.

THERE WILL BE A LULL IN PRECIP ACTIVITY LATER THIS MORNING BEFORE THE
NEXT WAVE RIDES UP ALONG THE FRONT AND BRINGS A RENEWAL OF PCPN
LATER TODAY. POPS WILL DECREASE BACK TO CHC RANGE ACROSS THE SRN
AREAS AND THEN RAMP UP LATER. P-TYPE WILL BE RAIN IN 99 PCT OF THE
AREA TODAY WITH THE EXCEPTION BEING ACROSS THE SRN POCONOS WHERE IP
WILL PROBABLY MIX IN BEFORE TONIGHT. THIS TRANSITION WITH THE COLD
ADVECTION IS A TRICKY CALL. TEMPERATURES WILL FALL STEADILY ACROSS
THE AREA TODAY WITH READINGS STARTING IN THE 50S/LOW 60S BEFORE DAWN
AND DROPPING IN THE TO THE 30S/LOW 40S (NORTH) BY LATE AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
THE NEXT WAVE WILL ARRIVE OVERNIGHT AND BRING A DECENT ROUND OF RAIN
TO MUCH OF THE AREA. TEMPERATURES ACROSS THE SRN POCONOS AND NRN NJ
WILL BE MARGINAL AND P-TYPE ISSUES ABOUND. WE EXPECT THAT IT WILL
BECOME COLD ENOUGH FOR SOME SNOW AND IN BETWEEN A SLEETY MIX AND A
CHANCE FOR SOME FREEZING RAIN ALSO. CONFID IN FREEZING RAIN IS
LOW...SINCE GROUND TEMPERATURES WILL NOT HAVE YET COOLED ENOUGH TO
FREEZE MUCH. WE SCALED BACK ZR P-TYPE WORDING TO CHC FOR NOW AND
WILL PASS ON ANY ADVISORY. A SLUSHY COATING TO IP/SN WITH UP TO AN
INCH WILL BE FOUND OVER THE NRN MOST AREAS.  PRECIP ENDS GRADUALLY
FROM W TO E AFTER MIDNIGHT AND WILL PROBABLY BE DONE IN MOST AREAS
BY DAWN SAT.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
A BREAK IN THE WEATHER LOOKS LIKELY FOR SATURDAY INTO SATURDAY NIGHT
BEFORE A RETURN OF UNSETTLED WEATHER FOR THE END OF THE WEEKEND INTO
EARLY NEXT WEEK. THE FRONT COLD FRONT AFFECTING THE AREA TODAY WILL
HAVE PUSHED TO OUR SOUTH BY SATURDAY MORNING. IT IS POSSIBLE SOME
LINGERING SHOWERS MAY OCCUR FOR OUR COASTAL AND SOUTHERN AREAS EARLY
ON SATURDAY, BUT DRIER AIR IS EXPECTED TO BUILD ACROSS THE AREA AND
THERE WILL NOT BE MUCH OF ANY VORTICITY IMPULSES TO HELP CREATE ANY
SHOWER ACTIVITY FOR THE REMAINDER OF THE DAY. HIGH PRESSURE WILL
BEGIN PUSHING INTO THE AREA FROM THE WEST LATE SATURDAY INTO
SATURDAY NIGHT WHICH SHOULD HELP KEEP THE WEATHER DRY INTO SATURDAY
NIGHT.

THE HIGH PRESSURE WILL LIFT INTO THE NORTHEAST ON SUNDAY, WHICH WILL
ALLOW A WARM FRONT TO BEGIN LIFTING INTO THE AREA SUNDAY NIGHT INTO
MONDAY MORNING AS AN AREA OF LOW PRESSURE MOVES INTO THE GREAT LAKES
REGION. AS THE LOW CONTINUES TO LIFT INTO SOUTHEAST CANADA ON
MONDAY, IT WILL DRAG A COLD FRONT ACROSS OUR AREA. SEVERAL SHORT
WAVES/VORTICITY IMPULSES ARE EXPECTED TO AFFECT THE AREA DURING THIS
PERIOD WHICH WILL ALLOW PERIODS OF PRECIPITATION TO OCCUR THROUGH
THE TIME FRAME. THE PRECIPITATION MAY START OUT AS EARLY AS SUNDAY
ACROSS OUR SOUTHERN AREAS AS THE FIRST OF THE VORTICITY IMPULSES
MOVES INTO THE AREA. WITH COLD AIR IN PLACE, THIS PRECIPITATION WILL
POSSIBLY START OUT AS A WINTRY MIXTURE FOR SUNDAY INTO SUNDAY NIGHT,
BEFORE POSSIBLY CHANGING TO RAIN MONDAY AS WARMER AIR MOVES IN. A
GOOD PORTION OF THE AREA COULD SEE A SNOW/SLEET ACCUMULATION BEFORE
THE CHANGE OVER TO RAIN. THERE IS ALSO THE POTENTIAL FOR A PERIOD OF
FREEZING RAIN TO OCCUR, ESPECIALLY FOR OUR NORTHERN HALF OF THE CWA.
OUR NORTHERN ZONES COULD HOLD ON THE THE WINTRY MIXTURE LONGER INTO
MONDAY MORNING AS COLD AIR COULD GET DAMMED UP BEFORE THE WARM SURGE
PUSHES THROUGH. THE PRECIPITATION SHOULD BEGIN TO DISSIPATE MONDAY
NIGHT INTO TUESDAY AS THE FRONTAL BOUNDARY PUSHES FARTHER OFFSHORE.
HOWEVER, THERE STILL WILL BE A CHANCE OF PRECIPITATION INTO TUESDAY
AS COUPLE OF MORE VORTICITY IMPULSES SLIDE ACROSS THE AREA.

A RETURN OF DRIER AND COOLER WEATHER IS CURRENTLY EXPECTED FOR
WEDNESDAY INTO THURSDAY AS THICKNESSES DROP ACROSS THE AREA HIGH
PRESSURE BEGINS TO BUILD INTO THE AREA FROM THE WEST. A WEAK CLIPPER
SYSTEM MAY SKIRT TO OUR NORTH ON WEDNESDAY, BUT IS NOT EXPECTED TO
AFFECT OUR AREA. THERE IS THE POSSIBILITY OF SOME LAKE EFFECT SNOW
SHOWERS/FLURRIES LATER IN THE WEEK, BUT WE`LL INCLUDE THOSE AS WE
GET CLOSER AND CONFIDENCE IS HIGHER.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

VSBYS HAVE IMPROVED SOMEWHAT EARLY THIS MORNING AHEAD OF THE
APPROACHING COLD FRONT. THE SHOWERS HAVE BROUGHT DOWN SOME STRONGER
WINDS ALOFT. THE VSBYS WILL IMPROVE OVER THE NRN/ERN AREAS SHORTLY.
WINDS WILL BE MOSTLY SRLY/SWRLY FOR A FEW MORE HOURS...THEN FROPA
WITH WRLY WINDS BECOMING NWRLY BY LATE MORNING. WINDS GUSTS AROUND
20 KTS POSSIBLE. CONDITIONS MAY IMPROVE TO THE HIGHER PART OF MVFR
OR PERHAPS EVEN LOW ND VFR FOR AWHILE LATER THIS MORNING BEHIND THE
FIRST BATCH OF SHOWERS. CONFID IN VFR RETURNING IS RATHER LOW.

MORE RAINS ARRIVE FROM SW TO NE THIS AFTERNOON AND CONDITIONS WILL
AGAIN HEAD BACK TO IFR TONIGHT OVER MOST OF THE AREA. RAINS WILL
PROBABLY MIX WITH SLEET AND SNOW ACROSS THE FAR NORTH. WINDS WILL BE
MOSTLY NRLY/NERLY OVERNIGHT.

OUTLOOK...
SATURDAY-SATURDAY NIGHT...MOSTLY VFR. GUSTY N-NW WINDS 15-20 KT
POSSIBLE.

SUNDAY-MONDAY NIGHT...IFR/MVFR PROBABLE WITH RAIN/WINTRY MIX
SUNDAY-MONDAY. POSSIBLE IMPROVEMENT MONDAY NIGHT.

TUESDAY...MOSTLY VFR...POSSIBLE MVFR EARLY. RAIN/SNOW SHOWERS
POSSIBLE. GUSTY W-NW WINDS POSSIBLE.

&&

.MARINE...
PREFRONTAL CONDITIONS ON THE WATERS ARE APPROACHING SCA CRITERIA.
SEAS AT BUOY 44009 ARE LINGERING AROUND 4 FT AND THE WIND GUSTS ARE
PICKING UP WITH SOME GUSTS AROUND 20 KTS. I WILL LEAVE THE SCA FLAG
IN PLACE...SINCE HIGHER GUSTS MAY OCCUR WITH THE ARRIVAL OF THE
COLDER AIR LATER THIS MORNING. THE FLAG IS A RATHER LOW-END EVENT AT
BEST AND COULD BE TAKEN DOWN BEFORE THE 6PM EXPIRATION.

OUTLOOK...
SATURDAY-SATURDAY NIGHT...SMALL CRAFT ADVISORY, OR NEAR ADVISORY,
CONDITIONS POSSIBLE.

SUNDAY-SUNDAY NIGHT...SUB-ADVISORY CONDITIONS POSSIBLE SUNDAY,
BEFORE A RETURN TO SMALL CRAFT ADVISORY CONDITIONS SUNDAY NIGHT.

MONDAY-TUESDAY...SMALL CRAFT ADVISORY, OR NEAR ADVISORY, CONDITIONS
POSSIBLE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR
     ANZ450>455.

&&

$$

SYNOPSIS...ROBERTSON
NEAR TERM...O`HARA
SHORT TERM...O`HARA
LONG TERM...ROBERTSON
AVIATION...ROBERTSON/O`HARA
MARINE...ROBERTSON/O`HARA