Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 082336
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
636 PM EST MON FEB 8 2016

.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF OF THE MID ATLANTIC
COAST OVERNIGHT. THIS SYSTEM WILL THEN GRADUALLY MOVE OUT TO SEA
LATER TUESDAY INTO WEDNESDAY. A COLDER AIRMASS THEN SETTLES IN FOR
THURSDAY AND FRIDAY. AN ARCTIC COLD FRONT FRIDAY NIGHT OR SATURDAY
WILL USHER IN PERHAPS THE COLDEST AIR OF THE WINTER FOR NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WINTER STORM WARNING AND WINTER WEATHER ADVISORIES HAVE BEEN
ISSUED FOR PORTIONS OF THE AREA.

AS THE FIRST STRONG LOW PRESSURE SYSTEM CONTINUES TO PULL AWAY FROM
THE AREA TONIGHT, ANOTHER IS EXPECTED TO DEVELOP AND STRENGTHEN OFF
THE COAST TONIGHT, WHICH WILL HELP LEAD TO AN ACCUMULATING SNOWFALL.
AN AREA OF LOW PRESSURE IS CURRENTLY LOCATED ACROSS THE EASTERN
GREAT LAKES REGION, WITH A FRONTAL BOUNDARY EXTENDING SOUTH TOWARD
THE GULF COAST. AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG
THIS BOUNDARY OVERNIGHT, BEFORE MOVING OFFSHORE TOWARD DAYBREAK. THE
FRONT WILL WEAKEN AND STRETCH OUT INTO MORE OF A SURFACE TROUGH
OVERNIGHT. MEANWHILE, A COUPLE OF SHORT WAVE/VORTICITY IMPULSES WILL
SLIDE ACROSS THE AREA WITHIN THE SOUTHWEST FLOW. THE ASSOCIATED LIFT
FROM THE SURFACE TROUGH AND VORTICITY IMPULSES, COMBINED WITH
INCREASING MOISTURE IN THE DENDRITIC ZONE WILL LEAD TO DEVELOPING
SNOWFALL THIS EVENING AND OVERNIGHT. THE HEAVIEST SNOWFALL IS
EXPECTED TO BE ACROSS SOUTHEASTERN PENNSYLVANIA, SOUTHERN NEW
JERSEY, AS WELL AS NORTHERN AND CENTRAL DELMARVA WHERE 1 TO 3 INCHES
COULD FALL THROUGH DAYBREAK.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
SNOW IS EXPECTED TO BE ONGOING AT THE START OF TUESDAY AS THE
SURFACE TROUGH WILL REMAIN IN PLACE ACROSS OUR AREA AS THE COASTAL
LOW CONTINUES TO LIFT TO THE NORTHEAST. THE COMBINED LIFT FROM THE
SURFACE TROUGH, ALONG WITH A STRONGER VORTICITY IMPULSE EXPECTED
DURING THE DAY, WILL CONTINUE TO COMBINE WITH ENHANCED MOISTURE IN
THE DENDRITIC ZONE AND IS EXPECTED TO LEAD TO A PERIOD OF ENHANCED
SNOWFALL DURING THE DAY ACROSS THE AREA. IT MAY NOT SNOW THE
ENTIRE TIME DURING THE DAY TUESDAY, BUT WHEN IT DOES SNOW, THERE
COULD BE A FEW HEAVIER PERIODS. AN ADDITIONAL 1 TO 3 INCHES COULD
FALL ACROSS PORTIONS OF THE AREA. ACROSS THE SOUTHERN AREAS,
SNOWFALL COLD CHANGE OVER AND/OR MIX WITH RAIN AT TIMES DURING THE
DAY WHICH WOULD LIMIT THEIR ACCUMULATIONS DURING THE DAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A DEEP UPPER TROF/LOW WILL MOVE SLOWLY EASTWARD FROM THE MIDWEST
ACROSS THE NORTHEAST AND MID ATLANTIC REGIONS OVER THE NEXT 2-3
DAYS. THIS WILL RESULT IN PERIODS OF SNOW ACROSS THE FORECAST AREA
FOR MUCH OF THIS TIME. THE SNOW EVENT WILL BE IN PROGRESS OVER THE
AREA AT THE BEGINNING OF THIS EXTENDED PERIOD...TUES EVE...ALTHO
IT LOOKS LIKE THE MAJORITY OF THE SNOW MAY HAVE ALREADY FALLEN BY
THAT TIME. THIS UPPER SYS IS FAIRLY COMPLEX WITH A NUMBER OF
SHRTWV/VORT CENTERS ROTATING AROUND IT SO IT IS SMWHT DIFFICULT TO
SAY QUITE WHEN AND WHERE THE HEAVIER SNOW WILL FALL. OVERALL THIS
DOES NOT LOOK TO BE A MAJOR STORM WITH NO STRONG SFC LOW
DEVELOPMENT AND MAINLY JUST LIGHT OR MODERATE SNOW AT TIMES...AS
NOTED ABOVE. FOR TOTAL SNOW...MOST GUIDANCE INCLUDING WPC SEEMED
TO INDICATE A WEST-EAST BAND OF GREATER SNOWFALL ACROSS THE MIDDLE
OF OUR FCST AREA AND THAT IS REFLECTED IN OUR TOTAL SNOW GRID.

THE SNOW SHOULD HAVE MOSTLY ENDED BY EARLY WED MORNING...HOWEVER
THE UPPER TROF WILL REMAIN OVER THE AREA DURING THE DAY ON WED SO
SCATTERED SNOW SHOWERS WILL REMAIN A POSSIBILITY. THERE WILL BE
DECENT COLD ADVECTION BEHIND THE SYSTEM FROM LATE WEDNESDAY INTO
FRIDAY RESULTING IN TEMPS WELL BELOW NORMAL TOWARD THE END OF THE
WEEK. HOWEVER EVEN COLDER ARCTIC AIR WILL PUSH INTO THE AREA ON
SATURDAY WITH SOME OF THE COLDEST TEMPS OF THE WINTER EXPECTED AT
THAT TIME. THIS PERIOD IS EXPECTED TO BE MOSTLY DRY HOWEVER THERE
COULD BE SNOW SHOWERS OR SQUALLS WITH THE ARCTIC FRONTAL PASSAGE.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...VFR CEILINGS LOWERING TO MVFR BY LATE THIS EVENING, THEN
MAINLY IFR OVERNIGHT. SOME SNOW IS EXPECTED TO OVERSPREAD AT LEAST
PARTS OF THE REGION STARTING LATER THIS EVENING, WITH MUCH OF IT
FOCUSED FROM KABE TO KPNE TO KACY ON SOUTH AND WEST. THE SNOW WILL
LOWER THE CEILINGS AND VISIBILITIES WITH PERHAPS A BURST OF SNOW
OCCURRING TOWARD DAYBREAK TUESDAY. EAST TO NORTHEAST WINDS MAINLY
LESS THAN 10 KNOTS.

TUESDAY...IFR CONDITIONS WITH PERIODS OF SNOW, HOWEVER ESPECIALLY
NORTH OF KPHL THE CEILINGS MAY IMPROVE TO MVFR FOR AWHILE. WE
ANTICIPATE A PERIOD OF MODERATE TO PERHAPS HEAVY SNOW TOWARD THE
LATE AFTERNOON HOURS. THE AXIS OF THIS HEAVIER SNOW WILL DEPEND ON
THE POSITIONING OF A NORTHWEST TO SOUTHEAST BOUNDARY. OUR CONFIDENCE
IN THE TIMING OF THE HEAVIER SNOW IS ON THE LOWER SIDE, HOWEVER IT
DOES APPEAR MOSTLY EARLY IN THE DAY AND THEN LATER IN THE DAY.
NORTHEAST WINDS MOSTLY 10-15 KNOTS, BECOMING NORTH LATER IN THE
DAY.

OUTLOOK...
TUESDAY NIGHT...PERIODS OF SNOW EXPECTED TUE NIGHT BUT TAPERING
OFF TO SNOW SHOWERS WED MORNING. EXPECT WIDESPREAD MVFR/IFR CONDS
AND THE POSSIBILITY FOR LIFR IF THE HEAVIER SNOW BANDS DEVELOP.
LIGHT WINDS.

WEDNESDAY...LEFTOVER SNOW SHOWERS WILL TAPER OFF FROM WEST TO EAST
DURING THE DAY, WITH CONDITIONS IMPROVING TO VFR. BREEZY WLY
WINDS GUSTING TO 25 KT.

THURSDAY AND FRIDAY...VFR AND BREEZY NW WINDS GUSTING 20 TO 30 KT.

SATURDAY...POSSIBLE BRIEF MVFR OR IFR CONDS IN SNOW SHOWERS WINDS
BECOMING NW AND GUSTING TO 30 KT OR GREATER.

&&

.MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT ACROSS THE ATLANTIC COASTAL
WATERS THROUGH TODAY AND TUESDAY. WINDS HAVE DIMINISHED AS THE FIRST
STRONG LOW PRESSURE SYSTEM PULLS AWAY, BUT WAVES WILL REMAIN
ELEVATED. ALSO, WINDS MAY INCREASE AGAIN TUESDAY AS ANOTHER LOW LOW
STRENGTHENS OFF THE COAST.

OUTLOOK...
TUESDAY NIGHT THRU THURSDAY...SMALL CRAFT CONDITIONS EXPECTED TO
CONTINUE THROUGH THE PERIOD WITH GALES POSSIBLE ON THURSDAY.

FRIDAY...SUB SCA CONDITIONS EXPECTED.

SATURDAY...WINDS/SEAS INCREASING AGAIN TO SCA AND POSSIBLY GALE
CONDITIONS.

&&

.TIDES/COASTAL FLOODING...
TONIGHT`S HIGH TIDE...
WITH RENEWED NORTHEAST FLOW AND WAVE ACTION, WIDESPREAD MODERATE
COASTAL FLOODING IS EXPECTED ALONG THE DE AND NJ OCEANFRONT DURING
THE HIGH TIDE AROUND 700 PM TO 8PM THIS EVENING, IN SPITE OF THE
LOWER ASTRONOMICAL TIDE. FOR DELAWARE BAY, WHERE HIGH TIDE IS
BETWEEN 11PM AND MIDNIGHT, EXPECT MINOR FLOODING WITH POCKETS OF
MODERATE FLOODING, PARTICULARLY WITH RESIDUAL HIGH WATER LEVELS
AND EKMAN TRANSPORT. THUS, A COASTAL FLOOD WARNING IS IN EFFECT
FOR THE ENTIRE DE AND NJ OCEANFRONT, AS WELL AS DELAWARE BAY.
MINOR NUISANCE FLOODING IS ALSO POSSIBLE FOR TIDAL SECTIONS OF THE
DELAWARE RIVER AND ITS TIDAL TRIBUTARIES WHEN HIGH TIDE OCCURS
AROUND 2 AM TUESDAY, INCLUDING PHILADELPHIA, WHERE A COASTAL FLOOD
ADVISORY IS IN EFFECT.

OVERALL, FOR THE DE AND NJ OCEANFRONT, WE EXPECT SIMILAR FLOODING
TONIGHT, COMPARED TO MONDAY MORNING`S HIGH TIDE. FOR DELAWARE BAY,
WE EXPECT GREATER FLOODING TONIGHT COMPARED TO MONDAY MORNING`S
HIGH TIDE WITH WIDESPREAD MINOR FLOODING AND POCKETS OF MODERATE
FLOODING.

TUESDAY MORNING`S HIGH TIDE...
WITH A STRONGER NORTHEAST FLOW AND HIGHER WAVE ACTION, WIDESPREAD
MODERATE COASTAL FLOODING WITH POCKETS OF MAJOR COASTAL FLOODING
IS EXPECTED ALONG THE DE AND NJ OCEANFRONT DURING THE TIME OF HIGH
TIDE AROUND 730 AM TO 830 AM. FOR DELAWARE BAY, THERE IS A HIGHER
LIKELIHOOD OF MODERATE FLOODING NEAR THE TIME OF HIGH TIDE BETWEEN
11 AM AND 12 PM. THE COASTAL FLOOD WARNING CONTINUES FOR THE ENTIRE
DE AND NJ OCEANFRONT AND DELAWARE BAY FOR THE TUESDAY MORNING HIGH
TIDE. WE ALSO EXPECT MINOR FLOODING FOR TIDAL SECTIONS OF THE
DELAWARE RIVER AND ITS TIDAL TRIBUTARIES WHEN HIGH TIDE OCCURS
AROUND 2 PM TUESDAY, INCLUDING PHILADELPHIA, WHERE A COASTAL FLOOD
ADVISORY CONTINUES.

OVERALL, FOR THE DE AND NJ OCEANFRONT, INCLUDING DELAWARE BAY,
WE EXPECT THE GREATEST IMPACT WITH THE HIGH TIDE TUESDAY MORNING
COMPARED WITH THE PREVIOUS TWO HIGH TIDES. IN FACT, THERE WILL BE
MORE WIDESPREAD ROAD FLOODING WITH ROAD CLOSURES IN SOME AREAS.
THERE WILL ALSO BE THE POSSIBILITY OF DAMAGE TO MORE VULNERABLE
STRUCTURES, ESPECIALLY FACTORING IN NEARSHORE WAVES OF 5 TO 10 FEET,
WHICH COULD ALSO RESULT IN SIGNIFICANT BEACH EROSION. IN PARTICULAR,
SOME BEACH AREAS WILL BE MORE SUSCEPTIBLE TO DAMAGE DUE TO BEACH
EROSION AND DAMAGE TO SHORE STRUCTURES THAT OCCURRED IN LATE JANUARY,
WITH EMPHASIS ON CAPE MAY COUNTY NJ AND THE DE OCEANFRONT.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR PAZ060-061-103-105.
     WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR PAZ070-071-101-102-104-106.
     COASTAL FLOOD ADVISORY UNTIL 6 PM EST TUESDAY FOR PAZ070-071-
     106.
NJ...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR NJZ009-010-012>015.
     COASTAL FLOOD WARNING UNTIL NOON EST TUESDAY FOR NJZ012>014-
     020>027.
     WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR NJZ016>025-027.
     COASTAL FLOOD WARNING UNTIL 4 PM EST TUESDAY FOR NJZ016.
     COASTAL FLOOD ADVISORY UNTIL 6 PM EST TUESDAY FOR NJZ015-
     017>019.
DE...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR DEZ003-004.
     COASTAL FLOOD WARNING UNTIL NOON EST TUESDAY FOR DEZ002>004.
     WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR DEZ001-002.
     COASTAL FLOOD WARNING UNTIL 4 PM EST TUESDAY FOR DEZ001.
MD...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR MDZ019-020.
     WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST
     WEDNESDAY FOR MDZ008-012-015.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...AMC/GORSE
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...AMC
AVIATION...AMC/GORSE
MARINE...AMC/ROBERTSON
TIDES/COASTAL FLOODING...


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