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000
FXUS61 KPHI 072051
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
351 PM EST FRI MAR 7 2014

.SYNOPSIS...
A COASTAL LOW PRESSURE SYSTEM WILL CONTINUE TO PULL AWAY FROM THE
REGION LATE TONIGHT. 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 PM THIS EVENING/...
AS OF MID AFTERNOON...A HIGH PRES RIDGE OVER NEW ENGLAND CONTS TO
WEAKEN WHIL LOW PRES IS DEEPENING OFF THE NC COAST. HI LEVEL CLDS
AND MOISTURE AHEAD OF THE ASSOCD UPPER LOW OVER NC/SC COVER THE FCST
AREA WHILE LOW CLOUDS HAVE SPREAD OVER ERN/SRN PARTS OF THE AREA ON
LOW-LVL NELY FLOW. SFC TEMPS ARE IN THE MID TO UPPER 30S FROM THE
POCONOS TO NORTHERN DELMAVA. NELY WINDS ARE NOTED ACROSS THE AREA
AND ARE RELATIVELY LIGHT NW BUT STRONGER SE TOWARDS THE ATLANTIC
COAST. RADAR SHOWS SOME VERY LIGHT RAIN OVER SRN DE.

FOR TONIGHT...THE SFC LOW IS FCST TO CONTINUE A GRADUAL DEEPENING AS
IT MOVES NEWD PAST CAPE HAT AND THEN OUT TO SEA. THE PRES GRADIENT
AROUND THE LOW WILL MAINTAIN A GOOD NELY FLOW THIS EVENING OVER SRN
NJ AND DE...THEN WINDS WILL BACK TO THE N AND DIMINISH SOME AS THE
LOW PRES MOVES AWAY FROM THE MID-ATLANTIC COAST. ASSOCD PRECIP
SHOULD STAY WELL S AND E OF PHL...WITH SRN DE AND EXTREME SE NJ
BEING THE ONLY PLACES LIKELY TO SEE ANY MEASURABLE RAIN...AND EVEN
THOSE AMOUNTS SHOULD BE ONLY A FEW HUNDRETHS. AT LEAST PARTIAL
CLEARING OF THE SKIES IS EXPECTED OVERNIGHT WHICH SHOULD ALLOW TEMPS
TO FALL INTO THE 20S IN MOST AREAS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
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 MOISURE 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 /SATURDAY THROUGH FRIDAY/...
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 LONGTERM 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 UNDERPERFORMING 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 /20Z FRIDAY THROUGH WEDNESDAY/...
THE MAIN LIMITING FACTOR FOR AVIATION TODAY IS THE CIGS. ABE/RDG ARE
VFR WHILE THE LOWER DEL VLY HAS SOME CIGS BKN 020-025 AND MIV/ACY
HAVE CIGS 015-020. THUS CONDS DETERIORATE SMWHT FROM NW TO SE AND
THE NELY WINDS ALSO INCRESE IN THE SAME PATTERN. THESE GENERAL CONDS
SHOULD CONTINUE FOR THE REST OF THE AFTN AND INTO MID EVE. THESE WX
ISSUES ARE CAUSED BY LOW PRES OFF THE NC COAST...AND SO AS THE LOW
MOVES OFF THE COAST STARTING LATE THIS EVE...CONDITIONS SHOULD BEGIN
TO IMPROVE AND BECOME VFR AT ALL LOCS OVERNIGHT. MIV AND ACY MAY
SEE SOME LIGHT RAIN AND FOG AT TIMES THIS EVENING AND THEY WILL
LIKELY BE THE LAST TO IMPROVE OVERNIGHT.

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...
A SFC LOW OFF THE NC COAST IS FCST TO CONTINUE GRADUALLY DEEPENING
AS IT MOVES NEWD PAST CAPE HAT THIS EVE AND THEN OUT TO SEA
OVERNIGHT. THE SFC PRES GRADIENT AND ASSOCD WINDS WILL BE STRONGEST
OVER THE COASTAL WATERS OF SRN NJ AND DE...AND SO A GALE WARNING
REMAINS IN EFFECT FOR THAT AREA. THE STRONGEST GUSTS SHOULD OCCURE
THIS EVENING...THEN WINDS WILL DIMINISH OVERNIGHT AND WILL BACK FROM
NE TO N TO NW BY SAT MORN. ELSEWHERE A SCA REMAINS IN EFFECT EXCEPT
FOR UPPER DEL BAY.

THE SUSTAINED NE FLOW HAS CAUSED SEAS TO BUILD TO 10 FT AT BUOY
44009 AND SOME FURTHER INCREASE IS POSSIBLE THIS EVENING. HIGHEST
SEAS DURG THE EVE 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 SATURDAY FOR ANZ450>452.
     GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR ANZ453>455.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ431.

&&

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