410
FXUS61 KPHI 150622
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
122 AM EST SUN DEC 15 2024
SYNOPSIS
STRONG HIGH PRESSURE PROGRESSES EASTWARD ACROSS THE
NORTHEASTERN U.S. TODAY BEFORE SHIFTING OFFSHORE TONIGHT. A
WEAK SYSTEM MOVES THROUGH TONIGHT AND MONDAY, FOLLOWED BY
ANOTHER SYSTEM LATER MONDAY INTO EARLY TUESDAY. HIGH PRESSURE
LOOKS TO BUILD IN BRIEFLY LATER TUESDAY BEFORE ANOTHER LOW
PRESSURE SYSTEM AFFECTS OUR REGION LATER WEDNESDAY INTO
THURSDAY.
NEAR TERM /THROUGH MONDAY/
AS OF EARLY THIS MORNING, SURFACE LOW PRESSURE IS IN WESTERN
ILLINOIS WHILE HIGH PRESSURE IS CENTERED OVER NORTHERN NEW
ENGLAND AND SOUTHERN QUEBEC. IN BETWEEN, OUR REGION REMAINS
FAIRLY TRANQUIL, THOUGH HIGH CLOUDS ARE STARTING TO MOVE
OVERHEAD. WITH THE LIGHT WINDS AND PARTLY CLEAR SKIES, TEMPS
HAVE FALLEN WELL BELOW FREEZING, BUT NOT QUITE AS COLD AS LAST
NIGHT IN MOST LOCALES.
FOR TODAY, THE INCREASING AND LOWERING CLOUD SHIELD MOVING IN
AHEAD OF THE APPROACHING SYSTEM WILL KEEP TEMPERATURE RISES IN
CHECK DESPITE AN EASTERLY FLOW OFF THE RELATIVELY WARM OCEAN.
THUS, HIGHS SHOULD BE MAINLY IN THE 30S NORTH AND WEST OF I-95
BUT IN THE LOWER 40S FURTHER SOUTH AND EAST. 20S WILL
PREDOMINATE AGAIN IN THE POCONOS.
WARM ADEVECTION PRECIP BEGINS MOVING IN NEAR SUNSET THIS
EVENING AND OVERSPREADS THE ENTIRE AREA BY MIDNIGHT OR SO. NEAR
AND SOUTHEAST OF I-95, THIS SHOULD JUST BE RAIN, THOUGH AN
LITTLE SNOW OR SLEET RIGHT AT THE ONSET CAN'T BE RULED OUT.
FURTHER NORTHWEST, SNOW MAY OCCUR LONG ENOUGH TO PRODUCE A
MODEST ACCUMULATION ACROSS THE I-78 CORRIDOR, BUT THEN TEMPS
SHOULD WARM AND WE END UP WITH MOSTLY RAIN AFTER MIDNIGHT. THERE
MAY BE A PERIOD OF FREEZING RAIN DURING THE TRANSITION AND THIS
MAY EVENTUALLY NECESSITATE A SOUTHWARD EXPANSION OF THE WINTER
WEATHER ADVISORIES, BUT NOT THAT CONFIDENT JUST YET. DID ADD
WARREN COUNTY NJ AS LATEST GUIDANCE PAINTS AN ICIER OUTCOME
THERE AND POINTS FURTHER NORTH AND WEST, WITH A TENTH TO PERHAPS
.15 INCH OF ICE AS THE SNOW TRANSITIONS TO RAIN TOWARD MORNING.
SNOW SHOULD ALSO LINGER LONG ENOUGH TO DROP AN INCH OR TWO,
ESPECIALLY ACROSS THE POCONO PLATEAU. THE EXISTING TIER OF
ADVISORIES WAS NOT CHANGED.
WARM ADVECTION SHOULD CHANGE PRECIP TO ALL RAIN BY MIDDAY MONDAY
IF NOT SOONER, JUST AS PRECIP IS WINDING DOWN, WITH JUST
LINGERING PATCHY LIGHT RAIN AND DRIZZLE IN THE WAKE OF THE
SYSTEM FOR THE AFTERNOON HOURS. THE SOUTHEASTERLY FLOW SHOULD
BRING TEMPS INTO THE 50S NEAR AND SOUTHEAST OF I-95 BY MONDAY
AFTERNOON, WITH 40S FURTHER NORTHWEST, THOUGH THE POCONO PLATEAU
MAY REMAIN STUCK IN THE UPPER 30S.
SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/
NEXT UPPER TROUGH BRINGS A COLD FRONT INTO THE REGION LATER
MONDAY NIGHT, WITH RAIN CHANCES INCREASING AGAIN. SOUTHERLY FLOW
WILL HOLD TEMPS UP, WITH TEMPS ONLY FALLING A FEW DEGREES FROM
THEIR HIGHS ON MONDAY AFTERNOON. THE FRONT WILL SWEEP OFF THE
COAST EARLY TUESDAY MORNING BRINGING RAIN/SHOWERS TO AN END WITH
SUNSHINE AND MILD TEMPERATURES TO FOLLOW. EXPECT HIGHS TUESDAY
MOSTLY IN THE 50S TO LOW 60S EXCEPT 40S IN THE SOUTHERN POCONOS.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
HIGH PRESSURE MOVES OFFSHORE ON WEDNESDAY WITH A FRONTAL SYSTEM
COMING IN WEDNESDAY NIGHT INTO THURSDAY. WEDNESDAY ITSELF LOOKS
PRETTY DRY AND MILD, WITH HIGHS LOOKING TO BE SEVERAL DEGREES
ABOVE NORMAL (UPPER 40S TO AS HIGH AS 60 OVER SOUTHERN
DELAWARE).
A DEEP TROUGH APPROACHES ON WEDNESDAY EVENING WITH A SURFACE
LOW DEVELOPING SOMEWHERE IN THE VICINITY. THIS WILL BRING SOME
LIGHT TO MODERATE RAIN TO THE AREA OVERNIGHT. COLDER AIR WORKING
IN ON THE BACKSIDE OF THE LOW COULD RESULT IN A FEW FLAKES IN
THE POCONOS, BUT THIS IS ANTICIPATED TO BE A RAIN EVENT
PRIMARILY. THE SYSTEM DOES NOT LOOK OVERLY IMPACTFUL AT THIS
TIME, JUST A BENEFICIAL RAIN.
BEYOND THURSDAY, THE FORECAST BECOMES HIGHLY UNCERTAIN. SOME
GUIDANCE WANTS TO KEEP A TRAIN OF SHORTWAVES ROTATING IN THROUGH
THE END OF THE WEEK, KEEPING SOME RAIN/SNOW SHOWERS AROUND
WHILE SOME HAVE HIGH PRESSURE BUILDING IN RESULTING IN DRY
WEATHER TO END THE WEEK. WHAT SOME OF THE LONGER RANGE GUIDANCE
IS ALSO SHOWING IS A POTENTIAL STORM OFF THE COAST THAT IS WORTH
WATCHING BUT NOTHING EVEN CLOSE TO CONCRETE YET, JUST SOMETHING
TO KEEP AN EYE ON IT. STUCK CLOSE TO THE NBM AS A RESULT. THERE
IS A BETTER CONSENSUS FOR TEMPERATURES RIGHT AROUND NORMAL FOR
THE END OF THE WEEK INTO THE WEEKEND.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z THIS MORNING...VFR. E-NE WINDS 5 KT OR LESS.
HIGH CONFIDENCE.
TODAY...VFR. E-NE WINDS 5 KTS OR SO. MODERATE CONFIDENCE.
TONIGHT...DETERIORATING TO IFR CIGS AND VSBY AFTER MIDNIGHT AS
RAIN OVERSPREADS THE REGION. FREEZING RAIN AND SNOW POSSIBLE AT
THE ONSET FOR KRDG AND ESPECIALLY KABE. E-NE WINDS 5 KTS OR SO.
LOW CONFIDENCE.
MONDAY...IFR CIGS MOST OF THE DAY WITH SOME CHANCE OF IFR VSBY
TOO DUE TO LINGERING MIST/DRIZZLE. WINDS BECOMING E-SE 5-10 KTS.
LOW CONFIDENCE.
MARINE
SUB-SCA CONDITIONS TODAY. HOWEVER, BUILDING SEAS NECESSITATED
ISSUANCES OF A SMALL CRAFT ADVISORY FOR OUR SOUTHERN AND CENTRAL
OCEAN ZONES STARTING THIS EVENING, SPREADING A LITTLE FURTHER
NORTH MONDAY MORNING. WINDS EASTERLY 5-10 KTS BUT WAVES WILL
REACH AROUND 5 FT STARTING THIS EVENING.
OUTLOOK...
MONDAY NIGHT THROUGH TUESDAY...A SYSTEM WILL BRING SOME RAIN
OVER THE WATERS AS WELL AS A PERIOD OF SMALL CRAFT ADVISORY
CONDITIONS LIKELY MONDAY NIGHT INTO TUESDAY.
WEDNESDAY...NO MARINE HEADLINES EXPECTED.
PHI WATCHES/WARNINGS/ADVISORIES
PA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST
MONDAY FOR PAZ054-055.
NJ...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 9 AM EST
MONDAY FOR NJZ001.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
MONDAY FOR NJZ007.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST MONDAY FOR ANZ451.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST MONDAY
FOR ANZ452>455.
SYNOPSIS...AKL/FITZSIMMONS/JOHNSON/RCM
NEAR TERM...RCM
SHORT TERM...FITZSIMMONS/RCM
LONG TERM...HOEFLICH
AVIATION...FITZSIMMONS/HOEFLICH/MPS/RCM
MARINE...FITZSIMMONS/HOEFLICH/RCM
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