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000
FXUS61 KPHI 080620
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
120 AM EST SAT MAR 8 2014

.SYNOPSIS...
LOW PRESSURE LOCATED OFF CAPE HATTERAS, NORTH CAROLINA WILL
CONTINUE TO MOVE EAST NORTHEASTWARD AND OUT TO SEA OVERNIGHT. A
COLD FRONT WILL THEN CROSS THE AREA FROM THE NORTHWEST LATE ON
SATURDAY INTO SUNDAY MORNING ALLOWING FOR A RETURN OF HIGH
PRESSURE FOR THE START OF THE NEW WORK WEEK. THE HIGH WILL DEPART
TO OUR SOUTH ON TUESDAY WHILE A CLIPPER LIKE SYSTEM NEARS FROM THE
WEST-NORTHWEST. THIS IS FOLLOWED BY THE POTENTIAL FOR ANOTHER
COASTAL LOW PRESSURE SYSTEM TO CROSS THE REGION LATE WEDNESDAY AND
THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LOW PRESSURE CENTERED OFF CAPE HATTERAS LATE EVENING WILL CONTINUE TO
MOVE TO THE EAST NORTHEAST AND OUT TO SEA DURING THE NIGHT.

THE NORTHWESTERN EDGE OF THE RAINFALL ASSOCIATED WITH THE LOW
MADE ITS WAY INTO THE FAR SOUTHEASTERN PART OF OUR FORECAST AREA
TODAY. HOWEVER, THE PRECIPITATION SHIELD WAS ON THE RETREAT THIS
EVENING AND IT WAS ENTIRELY OFF THE COAST AT 900 PM. AS A RESULT,
NO ADDITIONAL RAIN IS ANTICIPATED FOR THE OVERNIGHT HOURS.

THE HIGH CLOUDS WERE CONTINUING TO CLEAR FROM WEST TO EAST.
HOWEVER, STRATOCUMULUS COVERED MUCH OF OUR FORECAST AREA AT 900
PM. THE NORTHWESTERN EDGE OF THE STRATOCUMULUS EXTENDED FROM
AROUND STROUDSBURG TO ALLENTOWN TO MORGANTOWN IN PENNSYLVANIA. THE
CLOUD BASES WERE CONTINUING TO LOWER IN THE SUBSIDENCE ON THE
OUTER EDGE OF THE DEPARTING COASTAL LOW. ALSO, THE DOWNWARD MOTION
WAS CAUSING THE CLOUD DECK TO SPREAD NORTHWESTWARD. THE TREND MAY
CONTINUE UNTIL AROUND MIDNIGHT BEFORE THE DRY AIR TO OUR WEST AND
NORTHWEST PUTS A HALT TO THE EXPANSION OF THE CLOUDS. THE
STRATOCUMULUS SHOULD BEGIN TO ERODE FROM THE WEST AND NORTHWEST
AFTER MIDNIGHT WITH MOST LOCATIONS BECOMING CLEAR OR PARTLY CLOUDY
BY DAYBREAK. THE CLOUDS MAY LINGER UNTIL AROUND OR SHORTLY AFTER
DAYBREAK ALONG THE SOUTHERN NEW JERSEY COAST AND AT THE DELAWARE
BEACHES.

TEMPERATURES SHOULD REMAIN MOSTLY IN THE 30S WITH THE CLOUD COVER
PRESENT. READINGS ARE FORECAST TO FALL INTO THE 20S AT MOST
LOCATIONS ONCE THE CLEARING TAKES PLACE.

THE WIND SHOULD BE LIGHT AND VARIABLE FROM THE FALL LINE
NORTHWESTWARD AND IT WILL LIKELY BE FROM THE NORTH AROUND 5 TO 10
MPH ON THE COASTAL PLAIN. SPEEDS MAY APPROACH THE 10 TO 15 MPH
RANGE RIGHT ALONG THE COAST.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SUNDAY/...
SATURDAY LOOKS LIKE A PRETTY GOOD DAY WITH TEMPS CLOSE TO NORMAL
AND CONSIDERABLE SUNSHINE ESPECIALLY IN THE MORNING. WINDS SHOULD
BE RELATIVELY LIGHT W TO NW. WINDS AT 850MB ARE UP TO 40KT OR SO
BUT THERE APPEARS TO BE AN INVERSION ABOVE 950MB THAT WILL LIMIT
DOWNWARD MIXING DURING THE DAY. CLOUDS WILL INCREASE DURING THE
AFTN AS A COLD FRONT MOVES SEWD INTO NRN NJ AND ADJACENT PA. THERE
IS NOT MUCH MOISTURE WITH THE FRONT BUT WE HAVE PUT IN JUST A
SLIGHT CHC FOR -SHRA/-SHSN OVER THE POCONOS FOR LATE IN THE AFTN.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
THE 5-WAVE MODEL GUIDANCE IS SHOWING WEAK TROUGHING, PSEUDO-ZONAL
FLOW, ACROSS THE REGION AT THE START OF THE PERIOD. BY THE MIDDLE
OF NEXT WEEK WE START TO SEE A RETURN TO A RATHER FAMILIAR, AND
FRANKLY UN-WELCOME PATTERN, RIDGING IN THE WEST, TROUGHING IN THE
EAST. THE FEW BLISSFUL DAYS OF AT OR ABOVE AVERAGE TEMPERATURES
COMES TO HALT AND WINTER ONCE AGAIN TAKES GRASP OF THE REGION. THE
SILVER-LINING IN ALL OF THIS, AT LEAST WE GAIN AN EXTRA HOUR OF
DAYLIGHT ON THE CLOCKS IN THE EVENING...WE ACTUALLY ONLY GAIN A
FEW MINUTES OF ACTUAL DAYLIGHT ASTRONOMICALLY.

GENERALLY SPEAKING THE LATEST 12Z INITIALIZATION LOOKS PRETTY
GOOD OFF THE GFS/NAM/GGEM THOUGH THERE ARE MINOR DIFFERENCES IN
THE THERMAL FIELDS THIS MORNING...THE 12Z EC WAS SLIGHTLY BETTER
THAN THE THREE ABOVE. FOR THE MOST PART THE GUIDANCE SEEMS TO BE
TOO COLD ACROSS THE UPPER MID-WEST AND THE NORTHERN PLAINS AND NOT
FAST ENOUGH WITH THE NEXT COLD FRONT ENTERING INTO THE UPPER
PLAINS. THIS WILL CAUSE ISSUES FOR THE TEMPERATURE FORECASTS
THROUGH THE FIRST HALF OF THE LONG TERM PERIOD AS A PARADE OF
CLIPPER LIKE SYSTEMS SHOULD TRAVERSE CLOSE TO OUR REGION BEFORE
THE MORE ESTABLISHED TROUGHING TAKES OVER.

THE FIRST SUCH SYSTEM WILL TRACK WELL TO THE NORTH OF THE REGION
AND PUSH THROUGH A WEAKENING COLD FRONT LATER ON SATURDAY INTO
SUNDAY MORNING. GUIDANCE IS SHOWING THE LOW-LEVEL TEMPERATURES
CRASHING WITH THE ADVANCEMENT OF THE FRONT WHICH WOULD ALLOW FOR
MORE OF A RAIN/SNOW MIXTURE. THE ISSUE WITH THIS SYSTEM WILL BE
THE AMOUNT OR NO ASSOCIATED ICE WITHIN THE CLOUDS. THERE IS VERY
LIMITED, NEARLY NONE, MOISTURE BEING THAT THE SPLIT FLOW IN THE
MID-LEVELS CONTINUES AND WITH THE LITTLE FORCING ITS NOT LIKELY TO
BE A COLD ENOUGH CLOUD PRODUCER. THAT BEING SAID DECIDED TO ADD IN
SOME FREEZING DRIZZLE ACROSS OUR NORTHERN MOST ZONES WITH A
RAIN/SNOW MIX ELSEWHERE.

SUNDAY WILL BE A COLDER DAY WITH A STIFF NORTHWEST WIND AS
TEMPERATURES FALLING BELOW AVERAGE BEHIND THE FRONT. THE GOOD NEWS
IS THERE SHOULD BE PLENTY OF SUNSHINE AROUND TO MAKE IT NOT FEEL
AS BAD. DID SIDE MORE WITH THE WARMER MAVMOS IN THIS CASE GIVEN
THE ABOVE INFORMATION, THOUGH IT MUST BE NOTED THAT THE 2M
TEMPERATURES OFF THE GFS HAVE BEEN UNDER-PERFORMING THE PAST COUPLE
OF WEEKS...AT LEAST.

MONDAY WE WILL RESTART OUR WARMING TREND WITH RIDGING SLIDE TO
OUR SOUTH AND A NICE RETURN FLOW DEVELOPING. LOW-LEVEL
TEMPERATURES JUMP BACK UP ABOVE FREEZING AND WILL REMAIN THAT WAY
THROUGH AT LEAST THE LATER HALF OF TUESDAY, AHEAD OF THE NEXT
NORTHERN STREAM SYSTEM. BOTH MONDAY AND TUESDAY WILL FEATURE DRY
CONDITIONS AND ABOVE AVERAGE TEMPERATURES.

WE THEN TURN OUR ATTENTION TO LATER ON TUESDAY AS WE WATCH HOW
FAST/SLOW ANOTHER FRONTAL BOUNDARY WILL SHIFT THROUGH THE REGION.
GIVEN THE CURRENT SPEED OF THE NORTHERN STREAM WOULD HAVE TO ERR
ON THE SIDE OF A FASTER MOVEMENT OF THE COLD FRONT THUS DROPPING
IT THROUGH OUR REGION ON TUESDAY EVENING. THE NEXT BIG ISSUE
BECOMES HOW THE MID-LEVEL TROUGHING PROGRESSES THROUGH THE MID-
WEST AND INTO THE EASTERN U.S. BY MID-WEEK.

THERE IS RELATIVELY GOOD CONSENSUS FROM THE MID-RANGE MODEL
PACKAGE THROUGH ABOUT TUESDAY, AND THEN WE START TO SEE THE
GFS/GGEM/EC PART WAYS WITH THE SPEED AND DEEPENING OF THE TROUGH.
TO PUT IT SIMPLY, WE ARE WILL BE IN MID-MARCH WITH SPLIT FLOW
STILL ALOFT AND WE NEED A DEEP THERMAL TROUGH TO CHANGE THAT WITH
PHASING OF NORTHERN AND SOUTHERN STREAM SYSTEMS. WE THEN NEED TO
ROBUST WAVE TO DEVELOP ALONG THE FRONTAL BOUNDARY THAT JUST MOVED
THROUGH TO DRAG IN ENOUGH COLD AIR AND THEN SLING THE SOUTHERN
STREAM MOISTURE OVERHEAD. MUCH LIKE THE LAST EVENT, MARCH 2-3,
THERE ARE A LOT OF MOVING PARTS THAT NEED TO FALL IN-LINE FOR MORE
SNOW.

WHAT DOES HAVE SOMEWHAT HIGHER CONFIDENCE IS THE OCCURRENCE OF A
LOW PRESSURE MOVING BY/THROUGH THE REGION WEDNESDAY INTO THURSDAY
PRODUCING PRECIPITATION. THAT BEING SAID WENT WITH A WPC APPROACH
FOR POPS AND RAIN/SNOW MIXTURE FOR THE TIME BEING.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

OVERALL, MAINLY MVFR CEILINGS ARE EXPECTED AT THE TAF SITES
THROUGH ABOUT THE 08Z TO 10Z TIMEFRAME, AS THE CLOUDS SHOULD THEN
BEGIN TO ERODE FROM THE WEST AND NORTHWEST DURING THE EARLY
MORNING HOURS. KACY AND KMIV MAY HOVER AT LOW-END MVFR FOR SEVERAL
HOURS, WITH THE LOWER CIGS POSSIBLY LINGERING UNTIL SHORTLY AFTER
DAYBREAK. ELSEWHERE, KRDG AND KABE SHOULD SEE CLEARING AND A
RETURN TO VFR FIRST IN THE 08Z TO 10Z RANGE, FOLLOWED BY THE
DELAWARE VALLEY REGION, INCLUDING KPHL. MAINLY LIGHT AND VARIABLE
WINDS ARE EXPECTED AT KRDG/KABE THROUGH THE OVERNIGHT. ELSEWHERE, A
NORTHERLY WIND AT 10KT OR LESS WILL PREVAIL, BECOMING MORE
NORTHWEST TOWARD DAYBREAK AND THEN WEST- NORTHWEST WITH SOME
POSSIBLE GUSTS IN THE 15 TO 18KT RANGE FOR SATURDAY AFTERNOON FROM
AROUND KPHL SOUTH AND EAST.

OUTLOOK...
SATURDAY NIGHT - SUNDAY...MOSTLY VFR. LIGHT RAIN/SNOW SHOWERS
POSSIBLE EARLY SUNDAY MORNING NORTH OF RDG...MAYBE SOME PATCHY
FREEZING DRIZZLE LATE SATURDAY NIGHT.

MONDAY - TUESDAY...VFR.

TUESDAY NIGHT - THURSDAY...MVFR OR LOWER IN SCATTERED SHOWERS.
INCREASING CHANCES FOR MORE RAIN/SNOW WEDNESDAY INTO THURSDAY WITH
SUB-VFR CONDITIONS LIKELY.

&&

.MARINE...
BASED ON LATEST OBSERVATIONS OFF THE COASTS OF SOUTHERN NJ AND
DELAWARE, WE HAVE LET THE GALE WARNING EXPIRE AND TRANSITIONED
THESE AREAS TO A SMALL CRAFT ADVISORY, SIMILAR TO THE COASTAL
WATERS FARTHER NORTH OFF NJ. SOME WIND GUSTS BETWEEN 25 TO 30 KTS
ARE STILL EXPECTED THROUGH THE OVERNIGHT, ESPECIALLY OUT 20NM AWAY
FROM THE COAST AS SURFACE LOW PRESSURE CONTINUES TO MOVE
NORTHEASTWARD AND OUT TO SEA OVERNIGHT. WINDS WILL CONTINUE TO BE
MAINLY NORTHERLY OVERNIGHT AND THEN BACK TO THE NORTHWEST GOING
INTO SATURDAY MORNING. A SMALL CRAFT ADVISORY ALSO REMAINS IN
EFFECT FOR LOWER DELAWARE BAY THROUGH THE OVERNIGHT, AS WIND GUSTS
TO 25 KNOTS REMAIN POSSIBLE.

THE SUSTAINED NE FLOW HAS CAUSED SEAS TO BUILD TO 12 FT AT BUOY
44009. HIGHEST SEAS SHOULD BEGIN TO SUBSIDE OVERNIGHT...BUT WILL
REMAIN ELEVATED THROUGH THE DAY ON SATURDAY. A SCA WILL LIKELY
NEED TO CONT FOR COASTAL WATERS...EVEN AFTER WINDS DIMINISH.

OUTLOOK...
SUNDAY - TUESDAY...SUB-SCA CONDITIONS ARE EXPECTED AT THIS TIME.
WINDS BECOME MORE NORTHWESTERLY BEHIND A COLD FRONT ON SUNDAY.

TUESDAY NIGHT - THURSDAY...INCREASING CHANCES FOR A COASTAL LOW
PRESSURE TO NEAR LATER ON WEDNESDAY. SEAS AND WINDS WILL INCREASE
WITH THIS LOW. SCA CONDITIONS LOOKS VERY POSSIBLE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
     ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
     ANZ431.

&&

$$
SYNOPSIS...HEAVENER
NEAR TERM...IOVINO
SHORT TERM...AMC
LONG TERM...HEAVENER
AVIATION...KLINE/HEAVENER
MARINE...AMC/HEAVENER/KLINE