Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 071554
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1054 AM EST SUN FEB 7 2016

.SYNOPSIS...
LOW PRESSURE WILL DEEPEN RAPIDLY OFF THE SOUTHEAST COAST TODAY AND
TRACK NORTHEASTWARD OFF THE MID-ATLANTIC AND NORTHEAST COAST TONIGHT
INTO MONDAY. ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP IN
ITS WAKE NEAR THE MID-ATLANTIC COAST MONDAY NIGHT AND INTO TUESDAY.
ARCTIC HIGH PRESSURE IS THEN EXPECTED TO BUILD IN FROM THE NORTH AND
WEST DURING THE LATTER PART OF THE WEEK. ANOTHER COLD FRONT PASSING
THROUGH THE AREA WILL REINFORCE THE SUPPLY OF ARCTIC AIR INTO OUR
REGION NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO MAJOR CHANGES EXPECTED TO THE FORECAST FOR THE DAYTIME HOURS OTHER
THAN A FEW HOURLY CHANGES. WEAK HIGH PRESSURE GETS SQUEEZED OUT AS
THE COASTAL LOW TO THE SOUTH STRENGTHENS AND MOVES NORTH.

OVERALL, ANOTHER PLEASANT FAIR WEATHER DAY IS EXPECTED FOR THE
REGION WITH DRY CONDITIONS AND AMPLE SUNSHINE THROUGH THE DAY;
ALTHOUGH, SOME CIRRUS WILL BEGIN TO ADVANCE IN ACROSS THE AREA
AHEAD OF AN APPROACHING STORM SYSTEM ORGANIZING OFF THE SOUTHEAST
COAST. WINDS WILL START OUT LIGHT AND VARIABLE AND EVENTUALLY
TAKE ON A NORTH-NORTHEAST DIRECTION AS THE DAY WEARS ON, REMAINING
UNDER 10MPH. TEMPERATURES WILL END UP BEING A LITTLE BIT ABOVE
EARLY FEBRUARY NORMALS, AND WE GENERALLY USED A BLEND OF MET/MAV
GUIDANCE. HIGHS ARE EXPECTED TO REACH MOSTLY INTO THE MIDDLE AND
UPPER 40S, EXCEPT SLIGHTLY COOLER READINGS OVER THE SOUTHERN
POCONOS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THICKENING AND LOWERING CLOUDS WILL BE ARRIVING ACROSS THE REGION
FROM SOUTHEAST TO NORTHWEST AS OFFSHORE LOW PRESSURE TRACKS
NORTHEASTWARD OUT TO SEA AND AWAY FROM THE SOUTHEASTERN SEABOARD.
LATEST 0Z MODEL GUIDANCE KEEPS THIS STRONG LOW PRESSURE FAR ENOUGH
TO THE EAST TO KEEP OUR REGION PRECIP-FREE DESPITE THE INCREASING
CLOUD COVER. THE EXCEPTION TO THIS MIGHT BE FAR EASTERN AREAS NEAR
THE COASTS OF NEW JERSEY AND PERHAPS THE DELAWARE BEACHES WHERE WE
HAVE KEPT SOME SLIGHT CHANCE TO CHANCE POPS OVERNIGHT FOR THE
POSSIBILITY OF LIGHT RAIN OR SNOW. OTHERWISE NORTH-NORTHEAST WINDS
ARE EXPECTED ACROSS THE REGION THROUGH THE NIGHT WITH SPEEDS
INCREASING TO BETWEEN 10 TO 15 MPH. SOME GUSTS TO AROUND 25 MPH ARE
POSSIBLE INTO EARLY MORNING MONDAY NEAR THE COASTS OF NEW JERSEY AND
DELAWARE. OVERNIGHT LOW TEMPERATURES SHOULD BE A COUPLE OF DEGREES
MILDER THAN LAST NIGHT, WITH READINGS DROPPING OFF INTO THE UPPER
20S AND LOWER 30S FOR MOST OF THE REGION.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
THE SPREAD IN THE MODEL GUIDANCE HAS DECREASED FOR THE 00Z RUN
WITH THE TRACK OF STRONG OFFSHORE LOW ON MONDAY. MANY OF THE
PREVIOUSLY WESTERN OUTLIER SUCH AS THE NAM AND GEM HAVE TRENDED
FARTHER TO THE EAST AND IS MORE IN LINE WITH THE ECMWF/GFS
SOLUTIONS. INTERESTINGLY, MANY OF THE 03Z SREF ARW/NMB MEMBERS ARE
SHOWING A SEVERAL INCHES OF SNOW FOR US WITH THIS FIRST SYSTEM.
ASIDE FROM THE SREF, THERE IS NOW LITTLE SUPPORT FOR OUR IMPACT
FROM THIS STORM BEING MUCH MORE THAN SOME LIGHT SNOW OR FLURRIES
ALONG THE COAST ON MONDAY. EVEN WITH THE INCREASING SUPPORT THAT
THIS STORM WILL MISS OUR AREA, THIS POWERFUL STORM STILL BEARS
WATCHING IN THE UNLIKELY EVENT THAT IT TRENDS CLOSER TO THE COAST.
ONLY A 50 MILE (100 MILE) SHIFT IN THE TRACK BACK TO THE WEST
COULD RESULT IN ADVISORY (WARNING) LEVEL SNOWFALL CLOSE THE COAST
ACCORDING TO THE 00Z GEM. THOUGH VERY UNLIKELY, WE`VE SEEN CRAZIER
THINGS. AS MENTIONED YESTERDAY, MODEL CONSENSUS FOR DAYS LEADING
UP TO THE PAST TWO STORMS (THE LATE JANUARY BLIZZARD AND THE A
COUPLE OF DAYS AGO) HAD A DISTINCT EASTWARD BIAS IN THE TRACK.

OUR ATTENTION THEN TURNS UPSTREAM TO A DIGGING UPPER LOW OVER THE
GREAT LAKES REGION ON MONDAY. THERE IS GOOD AGREEMENT AMONG GUIDANCE
FOR LIGHT SNOW TO OVERSPREAD THE AREA FROM THE SOUTHWEST MONDAY
EVENING AS A LEADING SHORTWAVE TROUGH MOVES THROUGH THE MID
ATLANTIC. THERE IS STILL UNCERTAINTY IF THE ONSET OF THE LIGHT SNOW
WILL BE IN TIME TO FOR THE MONDAY AFTERNOON/EVENING COMMUTE OR IF IT
HOLDS OFF UNTIL AFTER.

AS THE PRIMARY SURFACE LOW MOVES OVER SOUTHERN VA, MODELS ARE
SHOWING IT TRANSFERRING ITS ENERGY TO A SECONDARY LOW THAT DEVELOPS
OFF THE COAST. THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THIS
MILLER-B COASTAL LOW ORGANIZING A BIT TOO LATE AND TOO FAR OFFSHORE
TO BRING HEAVIER SNOW BACK INLAND INTO THE FORECAST AREA. INSTEAD
THEY SHOW AN EXTENDED PERIOD OF MAINLY LIGHT SNOW MONDAY NIGHT
THROUGH TUESDAY NIGHT IN ASSOCIATION WITH THE WEAKER PRIMARY LOW.
ALTHOUGH PARTIAL THICKNESS NOMOGRAMS IMPLY ALL SNOW, THE BOUNDARY
LAYER IS MARGINALLY SUPPORTIVE OF SNOW, SO RAIN AND/OR MELTING OF
SNOW ON CONTACT WOULD CUT DOWN ON TOTALS AT LOWER ELEVATIONS...
ESPECIALLY WHEN PRECIP INTENSITY IS LIGHT. THERE STILL ISN`T ENOUGH
FORECAST CONFIDENCE TO GO WITH MUCH MORE THAN A WIDESPREAD 1-3
INCHES OF SNOWFALL FOR THIS EVENT. HOWEVER, WE NEED TO WATCH FOR THE
POTENTIAL FOR LOCAL ENHANCEMENT OF THE SNOWFALL LATE MONDAY NIGHT
INTO TUESDAY, ESPECIALLY IF THERE IS CSI PRESENT WITHIN THE INVERTED
TROUGH AXIS (I.E., A NORLUN TROUGH). THE PLACEMENT OF THE HEAVIER
BAND, IF IT DEVELOPS, IS STILL HIGHLY UNCERTAIN BUT THE TREND HAS
BEEN TO PLACE IT SOUTHWARD OVER SOUTHEASTERN PA-CENTRAL NJ. SOME
SHIFT IT EVEN FARTHER SOUTH INTO THE DELMARVA-SOUTHERN NJ ALTHOUGH
WARM SURFACE TEMPS COULD LIMIT THE POTENTIAL FOR HIGHER
ACCUMULATIONS THIS THIS FAR SOUTH. THE 00Z GFS IS QUITE MORE BULLISH
WITH SNOWFALL AMOUNTS AS IT HOLDS MORE ENERGY BACK WITH THE PRIMARY
LOW. THIS GFS RUN ALSO KEEPS ACCUMULATING SNOW OVER OUR AREA FOR 60
HOURS, WHICH SEEMS DOUBTFUL.

WILL KEEP A CHANCE FOR LIGHT SNOW SHOWERS IN THE FORECAST FOR
WEDNESDAY AS THE UPPER LOW OPENS UP AND PROGRESSES THRU THE AREA. A
COLD FRONT WILL MOVE THROUGH THE REGION LATE WEDNESDAY. IN ITS WAKE,
THE LEADING EDGE OF ARCTIC AIR ADVANCES INTO THE REGION. TEMPS
THURSDAY AND FRIDAY WILL STRUGGLE TO GET ABOVE FREEZING IN THE
COASTAL PLAIN AND LIKELY REMAIN IN THE 20S NORTH AND WEST OF THE
FALL LINE. A REINFORCING SHOT OF ARCTIC AIR IS FORECAST TO TAKE AIM
FOR THE MID-ATLANTIC AND NORTHEAST STATES AS A PIECE OF THE WELL-
KNOWN POLAR VORTEX DIGS INTO SOUTHEASTERN CANADA. TEMPERATURES
COULD BE 15-20F BELOW NORMAL FOR NEXT WEEKEND.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TODAY...VFR CONDITIONS ARE EXPECTED THROUGH TODAY. MAINLY CLEAR
SKIES ARE EXPECTED, WITH PERHAPS SOME CIRRUS WORKING IN ACROSS THE
REGION LATE IN THE DAY. WINDS EARLY WILL START OUT CALM OR LIGHT AND
VARIABLE, EVENTUALLY TAKING ON A NORTH-NORTHEAST DIRECTION WITH
SPEEDS ONLY AVERAGING ABOUT 4 TO 6 KNOTS.

TONIGHT...MAINLY VFR CONDITIONS THROUGH MOST OF THE NIGHT, WITH SOME
POSSIBLE SUB-VFR DEVELOPING TOWARD DAYBREAK MONDAY, ESPECIALLY
ACROSS EASTERN NJ DUE TO AN APPROACHING OFFSHORE STORM. THERE IS
INCREASING POTENTIAL FOR A PERIOD OF SNOW ACROSS THE COASTAL AREAS
OF NEW JERSEY AND DELAWARE. CONTINUED NORTHEAST WINDS ARE
EXPECTED WITH SPEEDS INCREASING OVERNIGHT TO DAYBREAK MONDAY INTO
THE 10 TO 15 KNOT RANGE, WITH SOME GUSTS DEVELOPING LATE FOR
EASTERN NJ TO BETWEEN 20 TO 25 KNOTS.

OUTLOOK...

MONDAY AND TUESDAY...PRECIP MAY OVERSPREAD THE AREA MONDAY AFTERNOON
OR EVENING. IT MAY BE WARM ENOUGH AT THE ONSET TO BEGIN AS A RA/SN
MIX FOR PHL AND NEARBY TERMINALS...AND RAIN AT ACY/MIV. EVENTUALLY
IT WILL LIKELY TURN OVER TO SNOW FROM NW TO SE MONDAY NIGHT AND
CONTINUE AT TIMES INTO TUESDAY NIGHT. RIGHT NOW, IT APPEARS THAT
SNOWFALL RATES SHOULD PREDOMINATELY BE LIGHT DURING THIS EVENT BUT
THERE IS A POTENTIAL FOR LOCALLY HEAVIER BANDS TO DEVELOP. THE SNOW
WOULD RESULT IN PERIODS OF IFR/LIFR RESTRICTIONS. THERE IS STILL
CONSIDERABLE UNCERTAINTY CONCERNING THE IMPACTS TO THE TERMINALS
DURING THIS PERIOD.

WEDNESDAY...LEFTOVER SNOW SHOWERS WILL TAPER OFF FROM WEST TO EAST
DURING THE DAY. CONDITIONS WILL IMPROVE TO VFR AS WELL. BREEZY WLY
WINDS GUSTING TO 25 KT.

THURSDAY...VFR AND BREEZY NW WINDS. BREEZY NWLY WINDS GUSTING TO 30
KT.

&&

.MARINE...
TODAY...SUB-ADVISORY CONDITIONS WILL START THE DAY FOR THE AREA
WATERS, BUT WINDS WILL BEGIN TO INCREASE FROM SOUTH TO NORTH
DURING THE AFTERNOON AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN
AHEAD OF AN APPROACHING STORM SYSTEM FROM THE SOUTH. THIS WILL
LEAD TO SMALL CRAFT CONDITIONS DEVELOPING DURING THE AFTERNOON FOR
OUR OCEAN WATERS AS NORTHEAST WIND GUSTS BEGIN TO REACH INTO THE
25 TO 30 KNOT RANGE.

TONIGHT...AS THE LOW PRESSURE TRACKS NORTHEAST LATER TONIGHT, THE
PRESSURE GRADIENT TIGHTENS EVEN FURTHER, AND WE ANTICIPATE TO REACH
GALE GUSTS OF 35 KNOTS PLUS FOR OUR OCEAN WATERS. WE THEREFORE HAVE
ISSUED A GALE WARNING BEGINNING AT 8PM THIS EVENING AS THE GALE
GUSTS DEVELOP FROM SOUTH TO NORTH THROUGH OUR ATLANTIC COASTAL
WATERS. FOR DELAWARE BAY, WE ANTICIPATE SMALL CRAFT ADVISORY WIND
GUSTS OF 25 KNOTS TO ENSUE THIS EVENING AND OVERNIGHT, AND THE SCA
FLAG BEGINS AT 8PM FOR THE UPPER AND LOWER BAY.

OUTLOOK...

MONDAY...THE GALE WATCH WAS CONVERTED TO A WARNING FOR THE COASTAL
ATLANTIC WATERS FOR MONDAY. MOST GUIDANCE SHOWS THE POTENTIAL FOR
FREQUENT GUSTS TO 35 KT, ESPECIALLY THE FARTHER OFFSHORE YOU GO. THE
GALE WARNING IS IN EFFECT UNTIL NOON THOUGH IT MAY BE ABLE TO BE
CANCELLED EARLIER FROM SOUTH TO NORTH AS THE LOW TRACKS WELL EAST OF
LONG ISLAND. SCA CONDITIONS WILL LIKELY FOLLOW DURING THE AFTERNOON.

MONDAY NIGHT THROUGH WEDNESDAY...ANOTHER AREA OF LOW PRESSURE WILL
DEVELOP OFF THE MID-ATLANTIC COAST. AN EXTENDED PERIOD OF SCA
CONDITIONS LIKELY DURING THIS TIME. IT COULD POTENTIAL REACH GALE
FORCE LATE WEDNESDAY BUT UNCERTAINTY IS VERY HIGH REGARDING THE
STRENGTH OF THE WINDS.

THURSDAY...SOLID SCA CONDITIONS. NW WINDS BEHIND A COLD FRONT COULD
APPROACH GALE FORCE.

&&

.TIDES/COASTAL FLOODING...
***WE ARE WATCHING TWO POTENTIAL COASTAL FLOOD EVENTS NEAR THE
MONDAY MORNING HIGH TIDE AND TUESDAY MORNING HIGH TIDE***

THE FLOW WILL BECOME ONSHORE THIS AFTERNOON AS HIGH PRESSURE
ANCHORS OVER SOUTHEAST CANADA AND LOW PRESSURE DEVELOPS OFF THE
SOUTHEAST COAST. THIS AREA OF LOW PRESSURE IS EXPECTED TO PASS
WELL EAST OF OUR REGION. WITH THE AFOREMENTIONED HIGH REMAINING
TO OUR NORTH, ANOTHER AREA OF LOW PRESSURE WILL DEVELOP OFF THE
OUTERBANKS OF NORTH CAROLINA MONDAY NIGHT AND PASS SOUTHEAST OF
OUR REGION DURING THE DAY TUESDAY.

THESE TWO SYSTEMS WILL MAINTAIN AN ONSHORE COMPONENT TO THE FLOW
ALONG THE COAST TO VARYING DEGREES SUNDAY THRU TUESDAY.
ASTRONOMICAL TIDES WILL BE HIGH TO BEGIN WITH GIVEN THE NEW MOON
TOMORROW.

FOR THE MONDAY MORNING HIGH TIDE, THE THREAT OF COASTAL FLOODING
WILL BE HIGHEST ALONG THE NORTHERN NJ COAST, WHERE THE GREATEST
COMPONENT OF ONSHORE FLOW WILL BE PRESENT. GIVEN THE SHORT
DURATION OF STRONGER ONSHORE FLOW, THE WIND BACKING FROM THE
NORTHEAST TO NORTH /MORE OFFSHORE/ AS WE APPROACH HIGH TIDE,
AND CONTINUED UNCERTAINTY REGARDING THE STORM TRACK, CONFIDENCE
REGARDING IMPACTS IS LOW. THE LATEST INDICATION IS ANY COASTAL
FLOODING WOULD BE MINOR (ADVISORY LEVEL).

REGARDING THE TUESDAY MORNING HIGH TIDE, WE EXPECT STRONGER
ONSHORE FLOW. ASIDE FROM A BRIEF LULL IN THIS FLOW LATE MONDAY,
WE`LL HAVE HAD NEARLY 48 HOURS DURATION OF ONSHORE FLOW, WHICH
WILL MAKE FOR POSITIVE TIDAL DEPARTURES TO BEGIN WITH. IN
ADDITION, A MORE EASTERLY WIND WILL MAKE FOR A LONGER FETCH IN
TERMS OF BUILDING WAVE ACTION. AT THIS TIME, THERE IS THE
POTENTIAL FOR MORE WIDESPREAD MINOR COASTAL FLOODING ALONG THE
ATLANTIC COAST AND ALSO FARTHER UP THE DELAWARE BAY. A FEW
LOCATIONS ON THE ATLANTIC COAST MAY EXPERIENCE MODERATE FLOODING
TUESDAY MORNING BUT CONFIDENCE IS NOT VERY HIGH YET.

PLEASE STAY TUNED TO LATER FORECASTS AND POSSIBLE HEADLINES.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 8 PM THIS EVENING TO NOON EST MONDAY FOR
     ANZ450>455.
     SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EST MONDAY
     FOR ANZ430-431.

&&

$$
SYNOPSIS...KLEIN
NEAR TERM...KLINE/ROBERTSON
SHORT TERM...KLINE
LONG TERM...KLEIN
AVIATION...KLEIN/KLINE
MARINE...KLEIN/KLINE
TIDES/COASTAL FLOODING...


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