573
FXUS61 KPHI 200746
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
246 AM EST SAT DEC 20 2025
SYNOPSIS
HIGH PRESSURE WILL MOVE OFFSHORE OF THE VIRGINIA AND NORTH
CAROLINA COASTS LATER TODAY INTO TONIGHT. A COUPLE OF DRY COLD
FRONTS ARE EXPECTED TO MOVE ACROSS THE AREA SUNDAY AND EARLY
MONDAY, FOLLOWED BRIEFLY BY HIGH PRESSURE LATER MONDAY. A WARM
FRONT AND SUBSEQUENT COLD FRONT IS THEN FORECAST TO MOVE ACROSS
THE AREA AROUND TUESDAY INTO EARLY WEDNESDAY, FOLLOWED BRIEFLY
BY HIGH PRESSURE LATE WEDNESDAY. A PAIR OF WEAK DISTURBANCES
COULD THEN AFFECT THE AREA FOR THE END OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
THRU DAWN, WINDS WILL CONTINUE TO DECREASE AS HIGH PRESSURE
BUILDS IN QUICKLY FROM THE OHIO VALLEY. TEMPS WILL MOSTLY BE IN
THE 20S WITH SOME TEENS ON THE POCONO PLATEAU. WINDS CHILLS WILL
BE IN THE TEENS MOST SPOTS WITH SINGLE DIGITS FOR MOUNT POCONO.
TODAY, SUNNY SKIES ARE EXPECTED WITH DECREASING WINDS THIS
MORNING. HIGH PRESSURE ARRIVES ACROSS THE REGION EARLY THIS
AFTERNOON THEN MOVES OFF THE COAST. WINDS WILL SWITCH AROUND
FROM WEST/NORTHWEST TO SOUTHWEST BY SUNSET. HIGH TEMPS TODAY
WILL BE COOL BUT THE SUNSHINE WILL MAKE IT FEEL BETTER. HIGHS
WILL BE IN THE UPPER 30S/LOW 40S FOR THE S/E AREAS AND LOW/MID
30S N/W. SO, OVERALL, ABOUT 4 TO 6 DEGREES BELOW NORMAL.
FOR TONIGHT, THE HIGH PRESSURE SYSTEM WILL BE OFFSHORE AND A
RETURN FLOW BEHIND IT SETS UP ACROSS THE MIDDLE ATLANTIC.
MEANWHILE, LOW PRESSURE ADVANCES ACROSS SOUTHERN CANADA WELL TO
OUR NORTH. THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS WILL
KEEP A SOUTH TO SOUTHWEST SYNOPTIC FLOW ACROSS OUR REGION. SKIES
WILL BE MOSTLY CLEAR EARLY, BUT THEN INCREASING CLOUDS ARE
EXPECTED LATE. OVERNIGHT LOWS WILL BE MILDER THAN THE CURRENT
NIGHT WITH LOWS DROPPING TO THE MID/UPPER 20S FOR THE NW AREAS
AND LOW 30S FOR DELMARVA, METRO PHILADELPHIA AND SOUTH NJ.
SHORT TERM /SUNDAY THROUGH MONDAY/
A DRY COLD FRONT MOVES THROUGH EARLY SUNDAY, WITH A GUSTY
NORTHWEST WIND DEVELOPING. WE'LL LIKELY SEE GUSTS OF 25-30 MPH
DURING THE DAY WITH THE COLD ADVECTION BEHIND THE FRONT. THAT
SAID, IT ACTUALLY LOOKS A LITTLE MILDER THAN SATURDAY, WITH
HIGHS REBOUNDING INTO THE 40S THANKS TO BETTER MIXING AND THE
WARM ADVECTION PRECEDING THE FRONT ITSELF. A FEW WRAPAROUND SNOW
SHOWERS OR FLURRIES MAY MAKE THEIR WAY INTO THE POCONOS, BUT
OVERALL DRY CONDITIONS SHOULD PREVAIL.
NORTHWEST WINDS CONTINUE WITH COLD ADVECTION ON SUNDAY NIGHT AS
HIGH PRESSURE VERY SLOWLY BUILDS EASTWARD FROM THE OHIO VALLEY.
COULD STILL BE SOME FLURRIES IN THE POCONOS, BUT OTHERWISE DRY.
LOWS DROP SUBSTANTIALLY FROM SATURDAY NIGHT, WITH TEENS POCONOS
AND LOW-MID 20S ELSEWHERE.
THE AFOREMENTIONED HIGH MOVES RIGHT ACROSS THE REGION OR JUST
TO THE SOUTH ON MONDAY, WITH LIGHTER WINDS. THIS SHOULD ALSO
ALLOW FOR SOME SUNSHINE, BUT WITH THE COLD ADVECTION PRECEDING
IT, HIGHS WILL BE NOTABLY COOLER, WITH 30S FOR MOST OF THE
REGION.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
ANOTHER SYSTEM WILL APPROACH FROM THE WEST MONDAY NIGHT,
CROSSING THE REGION ON TUESDAY. THIS WILL BRING AN INCREASING
RISK OF PRECIP AS IT PASSES, WITH THE HIGHEST CHANCE BEING LATE
MONDAY NIGHT INTO TUESDAY MORNING. WITH THE ANTECEDENT COLD AIR
MASS IN PLACE, IF PRECIP ARRIVES EARLY ENOUGH, IT COULD FALL IN
THE FORM OF SNOW. CHANCES OF THIS REMAIN NEAR 30-50% AND
CONFIDENCE ON ANY ACCUMULATION IS LOW DUE TO THE UNCERTAINTY IN
THE TIMING OF THE PRECIP ONSET AND QPF AMOUNTS. IF THE SYSTEM
TRENDS SLOWER AND PRECIP MOVES IN A BIT LATER, IT COULD END UP
BEING MOSTLY RAIN OUTSIDE OF THE HIGHER TERRAIN OF E PA AND N
NJ. OUR FORECAST INCLUDE LESS THAN 1" OF SNOW FOR ALL OF OUR
PENNSYLVANIA COUNTIES, MUCH OF OUR NEW JERSEY COUNTIES, AND
NORTHERN DELAWARE. A REASONABLE WORST CASE SCENARIO (SOMETHING
SIMILAR TO THE 00Z GFS) WOULD BE AROUND 1-2" OF SNOW AS FAR
SOUTH AS THE PHILLY METRO, AND PERHAPS AS MUCH AS 3-4" IN THE
HIGHER ELEVATIONS OF THE POCONOS AND NW NJ. WHILE THE FORECAST
CALLS FOR RELATIVELY LIGHT AMOUNTS, WE'LL HAVE TO KEEP AN EYE ON
THIS PERIOD, AS THE LIGHT SNOWFALL COULD IMPACT THE TUESDAY
MORNING COMMUTE. LOWS MONDAY NIGHT WILL BE IN THE MID 20S TO LOW
30S FOR MOST, BUT TEMPERATURES SHOULD WARM TO THE LOW TO MID
40S AS THE SYSTEM CROSSES THE AREA ON TUESDAY. SO ANY SNOW THAT
DOES FALL EARLY IN THE MORNING, IT SHOULD MELT AWAY PRETTY
QUICKLY.
THIS SYSTEM HAS LITTLE IF ANY COLD AIR BEHIND IT... IN FACT,
TEMPS SHOW MODERATION. THUS, LOWS TUESDAY NIGHT STAY IN THE 30S
FOR MOST, WITH HIGHS AGAIN IN THE 40S FOR WEDNESDAY (CHRISTMAS
EVE) AS ANOTHER HIGH PRESSURE MOVES IN FROM THE WEST, THIS ONE
BEING MORE PACIFIC IN ORIGIN AND WEAKER THAN ITS PREDECESSOR.
MOSTLY CLEAR SKIES AND LIGHT WINDS UNDER SAID HIGH MAY ALLOW
FOR SOME RADIATIONAL COOLING WEDNESDAY (CHRISTMAS EVE) NIGHT,
BUT A VERY WEAK DISTURBANCE MAY BRING CLOUDS OR EVEN A LITTLE
LIGHT PRECIP FOR THURSDAY (CHRISTMAS DAY) ITSELF. OVERALL
HOWEVER, THE MODERATING TREND WILL CONTINUE, WITH HIGHS LIKELY
APPROACHING OR EVEN POSSIBLY EXCEEDING 50 DEGREES.
UNCERTAINTY IS STILL PRETTY HIGH FOR FRIDAY (BOXING DAY), WITH
QUESTIONS REGARDING THE SPEED OF PASSING UPPER LEVEL IMPULSES,
BUT THE MAIN THEME IS MILD... WITH HIGHS LIKELY 50S MUCH OF THE
REGION AND POSSIBLY 60+ FROM PHILLY SOUTH. THE MAIN QUESTION IS
WHETHER ITS ACCOMPANIED BY SHOWERS OR NOT.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY... VFR EXPECTED WITH MOSTLY SUNNY SKIES. WEST WINDS
AROUND 10 KNOTS WILL SWITCH TO SOUTHWEST BY MID AFTERNOON AND
THEN CONTINUE TO BACK TO SOUTH LATE. HIGH CONFID.
TONIGHT... VFR CONTINUES WITH MOSTLY JUST HIGH CLOUDS EXPECTED.
SOUTH WINDS 5 TO 10 KNOTS. LLWS DEVELOPING WITH 35 TO 40 KTS AT
020 FROM THE SOUTHWEST. MEDIUM/HIGH CONFID.
OUTLOOK...
SUNDAY THROUGH MONDAY...VFR. GUSTY WNW WINDS ON SUNDAY.
MONDAY NIGHT INTO TUESDAY...RESTRICTIONS POSSIBLE DUE TO A
CHANCE (30-50%) OF RAIN OR SNOW AND LOW CLOUDS. CONDITIONS
IMPROVING LATE TUESDAY.
WEDNESDAY (CHRISTMAS EVE)...VFR. NO SIGNIFICANT WEATHER.
MARINE
WE DECIDED TO EXTEND THE GALE OUT SEVERAL MORE HOURS AS WIND
GUSTS REMAINED AT THE LOW-END OF THE GALE RANGE AT EXPIRATION
TIME. WE'LL CONVERT THE GALE TO SCA BY DAWN AND RUN IT INTO THE
MORNING. WINDS AND SEAS LOOK TO DECREASE RATHER QUICKLY AS THE
STRONG HIGH BUILDS OVERHEAD TODAY. TONIGHT, WE'LL BE IN THE
RETURN FLOW BEHIND THE HIGH AND WINDS WILL RETURN TO SCA LEVELS
OVERNIGHT. FAIR WEATHER TODAY AND TONIGHT.
OUTLOOK...
SUNDAY THROUGH SUNDAY NIGHT...SMALL CRAFT ADVISORY CONDITIONS
LIKELY DEVELOP SATURDAY NIGHT AND CONTINUE INTO SUNDAY NIGHT AS
ANOTHER COLD FRONT APPROACHES AND THEN PASSES THROUGH THE
REGION.
MONDAY THROUGH MONDAY NIGHT...HIGH PRESSURE PASSING OVERHEAD
LIKELY RESULTS IN CONDITIONS BELOW ADVISORY LEVELS.
TUESDAY...ANOTHER COLD FRONT APPROACHING THE REGION BRINGS A
RETURN OF ADVISORY CONDITIONS, WITH A SMALL RISK OF GALES AFTER
THE FRONT PASSES.
WEDNESDAY (CHRISTMAS EVE)...CONDITIONS SHOULD REMAIN BELOW
ADVISORY LEVELS. FAIR WEATHER.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ430-431-
450>455.
SYNOPSIS...RCM/STAARMANN
NEAR TERM...OHARA
SHORT TERM...RCM/STAARMANN
LONG TERM...RCM/STAARMANN
AVIATION...OHARA/RCM/STAARMANN
MARINE...OHARA/RCM/STAARMANN
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