Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 231803
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
103 PM EST TUE DEC 23 2014

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTHWARD ALONG
THE COAST EAST OF THE AREA TODAY, WHILE A FRONTAL BOUNDARY WILL
EXTEND SOUTHWARD INTO THE CAROLINA. ANOTHER LOW DEVELOPING ACROSS
THE DEEP SOUTH TODAY WILL LIFT NORTHWARD TONIGHT AND INTO THE
GREAT LAKES REGION WEDNESDAY INTO WEDNESDAY NIGHT. THE COASTAL
FRONT WILL BEGIN LIFTING NORTHWARD AS A WARM FRONT AND CROSS INTO
THE AREA WEDNESDAY, FOLLOWED BY A COLD FRONT WEDNESDAY NIGHT INTO
THURSDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE SOUTH
THURSDAY NIGHT INTO FRIDAY NIGHT, BEFORE PUSHING BACK SOUTHWARD
SATURDAY. AN AREA OF LOW PRESSURE WILL MOVE INTO EASTERN CANADA
THROUGH SATURDAY NIGHT, PULLING A COLD FRONT ACROSS THE AREA BY
SUNDAY MORNING. HIGH PRESSURE WILL BUILD ACROSS NEW ENGLAND INTO
EARLY NEXT WEEK, WHILE A LOW PRESSURE MAY PASS JUST TO OUR SOUTH
SUNDAY NIGHT INTO MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM UPDATE...NOT MANY CHANGES IN THE NEAR TERM AS THE FORECAST
IS ON TRACK. THERE IS CURRENTLY A BIT OF A LULL IN THE PRECIP
WHICH WILL LIKELY CONTINUE THROUGH AT LEAST EARLY AFTERNOON.

PREVIOUS NEAR TERM DISCUSSION...THE MID LEVEL PATTERN FOR TODAY
FEATURES A TROUGH OVER THE MIDDLE PART OF THE COUNTRY AND A RIDGE
OVER THE WESTERN NORTH ATLANTIC. WEAK IMPULSES ARE FORECAST TO
PASS OVERHEAD IN THE SOUTHWEST FLOW AND THEY WILL HELP TO TRIGGER
SOME LIGHT RAIN AT TIMES.

THE SURFACE HIGH CENTERED OVER ATLANTIC CANADA WILL CONTINUE TO
RECEDE TODAY GRADUALLY LOSING ITS INFLUENCE OVER OUR REGION. WEAK
SURFACE LOW PRESSURE LOCATED OFF THE MARYLAND COAST AROUND 630 AM
IS EXPECTED TO DRIFT NORTHWARD TO A LOCATION OFF THE CENTRAL PART
OF THE NEW JERSEY COAST TOWARD EVENING.

THE LOW LEVELS OF THE ATMOSPHERE SHOULD CONTINUE TO MOISTEN TODAY
WITH WARM ADVECTION ALOFT. AS A RESULT, THE SKY IS FORECAST TO
REMAIN OVERCAST AND WE WILL SEE PATCHY DRIZZLE ALONG WITH THE
AREAS OF LIGHT RAIN. SOME FOG IS LIKELY IN THE ELEVATED TERRAIN.

THE LIGHT EAST NORTHEAST WIND THIS MORNING SHOULD BECOME VARIABLE
FOR THIS AFTERNOON AS THE CENTER OF THE LOW ARRIVES. TEMPERATURES
ARE EXPECTED TO RISE ONLY A FEW DEGREES WITH HIGHS IN THE 40S TO
THE NORTHWEST OF THE FALL LINE AND MAINLY IN THE LOWER AND MIDDLE
50S ON THE COASTAL PLAIN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED FOR TONIGHT. THE
WEAK LOW OFF OUR COAST SHOULD DISSIPATE. WE ARE ANTICIPATING AN
OVERCAST SKY WITH SOME RAIN AND DRIZZLE. CEILINGS SHOULD LOWER
OVERNIGHT AND WE WILL LIKELY SEE AREAS OF FOG THROUGHOUT OUR
REGION. TEMPERATURES WILL CHANGE LITTLE DURING THE NIGHT AND THEY
MAY ACTUALLY BEGIN TO RISE A BIT TOWARD WEDNESDAY MORNING.

A WARM FRONT IS FORECAST TO LIFT TOWARD OUR REGION LATE TONIGHT
AND IT SHOULD REACH SOUTHERN DELAWARE AND THE ADJACENT COUNTIES OF
MARYLAND TOWARD DAYBREAK. RAINFALL RATES ARE EXPECTED TO INCREASE
LATE TONIGHT IN THE ISENTROPIC LIFT.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A WET START TO THE LONG TERM FORECAST, FOLLOWED BY A DRYING OUT
PERIOD FOR THE END OF THE WEEK, THEN SNOW POTENTIAL FOR THE END OF
THE WEEKEND?

THE LONG TERM STARTS OFF WITH AN EXTENDED PERIOD OF WET WEATHER
WEDNESDAY INTO WEDNESDAY NIGHT. AN AREA OF LOW PRESSURE DEVELOPING
ACROSS THE DEEP SOUTH TODAY WILL LIFT INTO THE GREAT LAKES
WEDNESDAY INTO WEDNESDAY NIGHT. WHILE DOING SO, A FRONTAL BOUNDARY
ALONG THE EAST COAST THAT EXTENDS TO OUR SOUTH WILL LIFT INTO THE
AREA DURING THE DAY WEDNESDAY. AMPLE LOW/MID LEVEL MOISTURE AND
LIFT WILL MOVE ACROSS THE AREA THROUGH THE DAY INTO THE NIGHT AND
LEAD TO PERIODS OF RAIN. NOT OVERLY EXCITED ABOUT THUNDERSTORM
POTENTIAL, BUT K-INDEX VALUES ARE IN THE LOW 30S AND TOTAL TOTALS
APPROACH 44/45, SO WOULD NOT BE TOO SURPRISED IF A FEW ISOLATED
LIGHTNING STRIKES OCCUR IN THE WARM SECTOR AS THE WARM FRONT LIFTS
THROUGH THE AREA; SO WE`VE EXPANDED THE ISOLATED THUNDER.

THE COLD FRONT APPROACHES FROM THE WEST DURING THE NIGHT
WEDNESDAY, AND SHOULD PUSH THROUGH BY THURSDAY MORNING. THERE
REMAINS PLENTY OF MOISTURE/LIFT ACROSS THE AREA SO PERIODS OF RAIN
WILL CONTINUE THROUGH THE NIGHT. THINK ANY THUNDER POTENTIAL
SHOULD PUSH EASTWARD DURING THE EVENING AS THE FRONT APPROACHES,
SO SHIFTED ISOLATED THUNDER ACROSS THE EASTERN HALF DURING THE
EVENING.

ALL PRECIPITATION WILL FALL AS RAIN WEDNESDAY INTO WEDNESDAY
NIGHT, AND AMOUNTS ARE EXPECTED TO BE AROUND A HALF INCH TO AN
INCH, WITH SOME HIGHER AMOUNTS OF ONE AND A HALF INCHES POSSIBLE
WEDNESDAY INTO WEDNESDAY NIGHT. EVEN WITH THE HIGHER END OF THE
EXPECTED RAINFALL, IT SHOULD NOT CAUSE ANY FLOODING PROBLEMS, SO
NO HEADLINES ANTICIPATED.

THE FRONT WILL CONTINUE TO OUR EAST DURING THE DAY THURSDAY. SOME
SHOWERS ARE POSSIBLE EARLY IN THE MORNING AS THE FRONT PULLS OUT.
HOWEVER, THE MAIN CONCERN WITH THURSDAY WILL BE THE WINDS.
SOUNDINGS SHOW THE BEST POTENTIAL FOR WINDS TO BE AROUND 30-35
MPH, BUT IF FULL MIXING OCCURRED, THERE COULD BE SOME GUSTS IN THE
LOW 40S. HOWEVER, STILL LOOKS TO BE BELOW ADVISORY LEVELS. THERE
IS SOME MOISTURE THAT SLIDES TO OUR NORTH DURING THE DAY ALONG
WITH A SHORT WAVE/VORT MAX, BUT LOW LEVEL LIFT IS LACKING. IT IS
POSSIBLE THAT SOME LAKE EFFECT SHOWERS WILL OCCUR TO OUR NORTH AND
WEST, BUT NOT CONFIDENT ON THEM REACHING OUR AREA, SO WILL LEAVE
THEM OUT FOR NOW.

A DRYING OUT PERIOD IS EXPECTED THURSDAY NIGHT INTO SATURDAY AS
HIGH PRESSURE BUILDS IN FROM THE SOUTH THURSDAY NIGHT INTO FRIDAY
NIGHT, THEN PUSHES BACK SOUTHWARD SATURDAY.

A COLD FRONT IS EXPECTED TO MOVE INTO THE AREA SATURDAY NIGHT
INTO SUNDAY, ALTHOUGH THERE IS SOME TIMING AND STRENGTH
DIFFERENCES WITH THE GFS AND ECMWF. THE GFS IS FASTER AND DRIER,
WHILE THE ECMWF AS WETTER AND SLOWER. WITH THE UNCERTAINTY, WILL
STILL NOT HIT THE PRECIPITATION CHANCES HARD AND KEEP SLIGHT
CHANCE TO CHANCE SATURDAY NIGHT INTO SUNDAY. BOTH MODELS DEVELOP
AN AREA OF LOW PRESSURE ALONG THE FRONT AFTER IT SAGS SOUTH OF THE
AREA INTO MONDAY, ALTHOUGH THERE CONTINUES TO BE TIMING
DIFFERENCES. THE GFS IS FURTHER SOUTH, WHILE THE ECMWF IS FARTHER
NORTH. WITH THE CONTINUING UNCERTAINTY, WILL ONLY KEEP SLIGHT
CHANCE TO CHANCE INTO SUNDAY NIGHT MONDAY. THE THING TO NOTE IS
WITH HIGH PRESSURE BUILDING TO THE NORTH, THERE COULD BE ENOUGH
COLD AIR THAT IF ANY PRECIPITATION DOES OCCUR THAT IT COULD BE
MORE SNOW THAN NOT. STILL A WAYS OUT, SO WE`LL SEE HOW IT
PROGRESSES IN THE DAYS TO COME.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

IT WILL BE A CHALLENGING DAY AND NIGHT FOR AVIATION INTERESTS, AS
IFR CONDITIONS ARE ANTICIPATED TO CONTINUE THROUGH THE TAF PERIOD.

WINDS SHOULD BECOME LIGHT AND VARIABLE OVER THE NEXT FEW HOURS. A
LIGHT EAST WIND MAY DEVELOP LATE TONIGHT.

OUTLOOK...
WEDNESDAY-WEDNESDAY NIGHT...SIGNIFICANTLY REDUCED CONDITIONS,
MOST LIKELY IFR/LIFR, WITH PERIODS OF RAIN, SOME HEAVY AT TIME.
SOME IMPROVEMENT POSSIBLE VERY LATE WEDNESDAY NIGHT.

THURSDAY...CONDITIONS IMPROVING TO VFR DURING THE MORNING. WEST
WINDS INCREASING AND GUSTY AT LEAST 25-30 KNOTS.

THURSDAY NIGHT-SATURDAY...MAINLY VFR. GUSTY SOUTHWEST WINDS 15-20
KNOTS SATURDAY.

&&

.MARINE...
THE PRESSURE GRADIENT BETWEEN THE WEAK LOW OFF THE MIDDLE
ATLANTIC COAST AND THE HIGH OVER EASTERN CANADA WAS MAINTAINING A
STEADY EAST NORTHEAST WIND ALONG OUR STRETCH OF THE COAST. WAVE
HEIGHTS ON OUR OCEAN WATERS RESPONDED AND THEY WERE IN THE 4 TO 7
FOOT RANGE AROUND 630 AM. WAVES ARE FORECAST TO REMAIN IN THAT
RANGE INTO THIS MORNING AS THE LOW MOVES NORTHWARD AND OVER OUR
COASTAL WATERS. A VERY SLOW DECREASE IN WAVE HEIGHTS IS EXPECTED
FROM THIS AFTERNOON INTO TONIGHT AS THE LOW DISSIPATES SLOWLY.

WE HAVE A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS. IT IS IN
EFFECT FOR OUR OCEAN WATERS OFF DELAWARE AND OFF THE MOUTH OF
DELAWARE BAY UNTIL 600 PM. THE ADVISORY GOES UNTIL 200 AM
WEDNESDAY FOR OUR OCEAN WATERS OFF NEW JERSEY.

WIND SPEEDS ARE EXPECTED TO DECREASE AND THEY SHOULD BE 10 KNOTS
OR LESS FROM LATE THIS MORNING INTO TONIGHT.

OUTLOOK...
WEDNESDAY-WEDNESDAY NIGHT...WINDS AND SEAS EXPECTED INCREASE TO
SMALL CRAFT ADVISORY LEVELS DURING THE DAY AND CONTINUE INTO THE
NIGHT.

THURSDAY...SMALL CRAFT ADVISORY LEVELS REMAIN BEHIND A COLD
FRONTAL PASSAGE, WITH NEAR GALE FORCE WINDS POSSIBLE.

THURSDAY NIGHT...CONDITIONS WILL RETURN BELOW ADVISORY LEVELS
OVERNIGHT THURSDAY.

FRIDAY-SATURDAY...SUB-SMALL CRAFT ADVISORY LEVELS, ALTHOUGH WINDS
MAY GUST NEAR 20 KNOTS ON SATURDAY.

&&

.TIDES/COASTAL FLOODING...
ALL TIDAL GAUGES SHOW CONDITIONS BELOW MINOR FLOODING THRESHOLDS.
THEREFORE, THE COASTAL FLOOD ADVISORY HAS BEEN CANCELLED. WITH THE
DECREASE IN THE ON SHORE FLOW, DO NOT ANTICIPATE ANY COASTAL
FLOODING ISSUES WITH THE NEXT FEW HIGH TIDE CYCLES.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EST
     WEDNESDAY FOR ANZ450>453.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EST THIS
     EVENING FOR ANZ454-455.

&&

$$
SYNOPSIS...ROBERTSON
NEAR TERM...IOVINO/JOHNSON
SHORT TERM...IOVINO
LONG TERM...ROBERTSON
AVIATION...IOVINO/ROBERTSON
MARINE...IOVINO/ROBERTSON
TIDES/COASTAL FLOODING...





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