539
FXUS61 KPHI 160523
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1223 AM EST TUE DEC 16 2025
SYNOPSIS
ARCTIC HIGH PRESSURE OVER THE MID-ATLANTIC SETTLES OVER THE
SOUTHEAST STATES TUESDAY THROUGH TUESDAY NIGHT BEFORE MOVING
OUT TO SEA. A WEAK FRONT PASSES THROUGH WEDNESDAY EVENING, THEN
A STRONG COLD FRONT MOVES THROUGH OUR REGION THURSDAY NIGHT AND
FRIDAY. HIGH PRESSURE RETURNS INTO THE WEEKEND, HOWEVER A WEAK
COLD FRONT PASSES THROUGH SUNDAY NIGHT. HIGH PRESSURE ONCE AGAIN
BUILDS IN FOR MONDAY.
NEAR TERM /THROUGH TODAY/
AS OF 815 PM, AN AREA OF LIGHT SNOW THAT APPROACHED FROM THE
WEST HAS WEAKENED AND IS PRODUCING MOSTLY SOME FLURRIES NOW ACROSS
PARTS OF THE REGION AS IT CONTINUES TO SHIFT EASTWARD CLOSER TO
THE COAST. THIS IS ALL WELL AHEAD OF STRENGTHENING WARM AIR
ADVECTION ALOFT TO OUR WEST. CLOUD COVER REMAINS AS A RESULT.
SURFACE HIGH PRESSURE SETTLES OFF TO OUR SOUTH TONIGHT BEFORE
GRADUALLY SHIFTING OFF THE SOUTHEAST COAST ON TUESDAY. THE CLOUD
COVER WILL CLEAR OUT OVERNIGHT AND WINDS WILL DIMINISH MORE AND
BECOME LIGHT AND VARIABLE. ANOTHER VERY COLD NIGHT IS EXPECTED
AS MUCH OF THE AREA SHOULD BE ABLE TO RADIATE PRETTY WELL
OVERNIGHT, ESPECIALLY WITH THE SNOW COVER. AS A RESULT, LOWS
SHOULD BOTTOM OUT IN THE LOW TO MID TEENS WITH SINGLE DIGITS IN
THE HIGHER ELEVATIONS. WITH LIGHT WINDS, WIND CHILLS WON'T BE
FAR OFF FROM THE ACTUAL AIR TEMPERATURES OVERNIGHT.
FOR TUESDAY, WITH THE HIGH SLOWLY SLIDING OFF THE COAST, THE
REGION WILL BEGIN TO ENCOUNTER SOUTHWESTERLY RETURN FLOW. THIS
SHOULD ALLOW TEMPERATURES TO MODERATE A BIT WHERE HIGHS WILL
MAINLY BE IN THE 30S (20S IN THE HIGHER TERRAIN). A SUNNY SKY
SHOULD PREVAIL IN THE MORNING, WITH AN INCREASE IN HIGH CLOUDS
IN THE AFTERNOON AS ANOTHER UPPER LEVEL DISTURBANCE APPROACHES
LATER IN THE DAY.
SHORT TERM /TONIGHT THROUGH THURSDAY/
HIGH PRESSURE SETTLES OFF THE SOUTHEAST COAST TUESDAY NIGHT,
AND WHILE RETURN FLOW SETS UP, THE COMBINATION OF SKIES CLEARING
OUT ENOUGH WITH WINDS LIGHT ENOUGH AND WITH LINGERING SNOWPACK
THAT TEMPERATURES SHOULD RADIATE DOWN INTO THE TEENS AND LOW
20S.
ZONAL FLOW SETS UP ON WEDNESDAY AND A WEAK TROUGH APPROACHES
FROM THE WEST. TEMPERATURES BEGIN TO MODERATE SOMEWHAT, BUT WILL
STILL BE BELOW NORMAL LEVELS TOPPING OFF IN THE LOW TO MID 40S.
HIGH PRESSURE THEN BUILDS BACK OVER THE AREA FOR WEDNESDAY
NIGHT AND THURSDAY. STILL COLD WEDNESDAY NIGHT WITH LOWS IN THE
20S, BUT THEN HIGHS REBOUND ON THURSDAY TO ABOVE NORMAL LEVELS
IN THE UPPER 40S TO LOW 50S NORTH AND WEST OF THE FALL LINE AND
IN THE LOW TO MID 50S ACROSS THE DELAWARE VALLEY, DELMARVA, AND
SOUTHERN NEW JERSEY.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
HIGH PRESSURE MOVES OUT TO SEA THURSDAY NIGHT, AND LOW PRESSURE
PASSING THROUGH THE GREAT LAKES WILL DRAG A COLD FRONT INTO THE
REGION LATE THURSDAY NIGHT AND FRIDAY. TEMPERATURES WILL BE
WARM ENOUGH FOR THIS TO BE A MOSTLY RAIN EVENT, THOUGH WITH COLD
AIR ADVECTION ON THE BACK SIDE OF THE SYSTEM, THERE MAY BE SOME
RAIN/SNOW MIX IN THE SOUTHERN POCONOS AND PORTIONS OF THE
LEHIGH VALLEY. THERE ARE SOME SIGNALS FOR SOME MODERATE TO
POSSIBLY EVEN HEAVY RAINFALL OVER THE AREA WITH THIS SYSTEM. THE
BULK OF THE RAIN, AT LEAST AT THIS TIME, LOOKS TO FALL BETWEEN
MIDNIGHT OR SO THURSDAY NIGHT THROUGH FRIDAY AFTERNOON. 13Z NBM
PROBABILITY OF 24 HOUR PRECIPITATION ENDING 7 PM FRIDAY IS 70 TO
80 PERCENT FOR GREATER THAN 0.5 INCHES AND 40 TO 60 PERCENT FOR
GREATER THAN 1 INCH. LOWS THURSDAY NIGHT WILL BE IN THE UPPER
30S TO LOW 40S, AND THEN HIGHS ON FRIDAY WILL BE IN THE UPPER
40S TO LOW 50S. THIS RAINFALL SHOULD TAKE CARE OF THE BULK OF
THE SNOWPACK OVER THE AREA.
COLD FRONT PASSES THROUGH BY FRIDAY NIGHT AND THEN ARCTIC HIGH
PRESSURE BUILDS BACK INTO THE REGION WITH LOWS IN THE 20S FRIDAY
NIGHT AND THEN HIGHS IN THE UPPER 30S TO LOW 40S ON SATURDAY.
SOME STRONG SHORTWAVES WILL PASS THROUGH THE REGION WITH MINIMAL
IMPACTS.
HIGH PRESSURE SLIDES OFFSHORE SATURDAY NIGHT AND TEMPERATURES
REBOUND ON SUNDAY WITH HIGHS IN THE MID TO UPPER 40S. A WEAK
FRONT MAY PASS THROUGH THE REGION SUNDAY NIGHT AND THEN HIGH
PRESSURE RETURNS ON MONDAY WITH NEAR TO SLIGHTLY BELOW NORMAL
LEVELS.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...VFR. CEILINGS WILL GRADUALLY CLEAR OUT OVERNIGHT.
SOME LINGERING FLURRIES REMAIN AROUND OVERNIGHT. WEST TO
SOUTHWEST WINDS AROUND 5 KNOTS, BECOMING LIGHT AND VARIABLE AT
TIMES. MODERATE CONFIDENCE.
TUESDAY...VFR. LIGHT AND VARIABLE WINDS BECOMING WEST-NORTHWEST
AROUND 5 KNOTS IN THE MORNING, THEN BECOMING WEST TO SOUTHWEST
IN THE AFTERNOON. HIGH CONFIDENCE.
TUESDAY NIGHT...VFR. A SOUTHWEST WIND AROUND 5 KNOTS WITH SOME
MID AND HIGH CLOUDS AROUND. HIGH CONFIDENCE.
OUTLOOK...
WEDNESDAY THROUGH THURSDAY...VFR/NSW.
THURSDAY NIGHT THROUGH FRIDAY...SUB-VFR CONDS IN RA THROUGH
FRIDAY AFTERNOON. SW WINDS GUSTING 25 TO 30 KT THURSDAY NIGHT,
TURNING W-NW ON FRIDAY.
FRIDAY NIGHT THROUGH SATURDAY...VFR/NSW.
MARINE
NO MARINE HEADLINES ARE EXPECTED THROUGH TUESDAY.
WEST WINDS WILL SETTLE OUT OF THE WEST-SOUTHWEST 15-20 KT
TONIGHT WITH SEAS OF 2-4 FEET. FOR TUESDAY, WEST-NORTHWEST
WINDS AROUND 10-15 KT AND SEAS OF 1-3 FEET ARE EXPECTED. FAIR
WEATHER.
OUTLOOK...
TUESDAY NIGHT...SUB-SCA CONDITIONS.
WEDNESDAY...MARGINAL SCA CONDITIONS MAY DEVELOP WITH GUSTS UP
TO 25 KT AND SEAS BUILDING TO 5 FEET.
WEDNESDAY NIGHT THROUGH THURSDAY...SUB-SCA CONDITIONS.
THURSDAY NIGHT THROUGH FRIDAY...STRONG SCA CONDITIONS
DEVELOPING WITH GALES POSSIBLE ON FRIDAY. VSBY RESTRICTIONS IN
RAIN AND FOG.
FRIDAY NIGHT...SCA CONDITIONS.
SATURDAY...SUB-SCA CONDITIONS.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...MPS
NEAR TERM...DESILVA/GORSE
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...GUZZO/MPS
MARINE...DESILVA/MPS
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