022
FXUS61 KPHI 080749
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
249 AM EST MON DEC 8 2025
SYNOPSIS
A COLD FRONT MOVES THROUGH THE REGION EARLY THIS MORNING. HIGH
PRESSURE THEN BUILDS INTO THE REGION LATER TODAY BEFORE BUILDING
OVERHEAD TONIGHT, THEN MOVING OFFSHORE ON TUESDAY. LOW PRESSURE
PASSES THROUGH THE REGION WEDNESDAY, FOLLOWED BY SEVERAL STRONG
COLD FRONTS. ARCTIC HIGH PRESSURE BUILDS INTO THE REGION FOR
THE END OF THE WEEK AND NEXT WEEKEND.
NEAR TERM /THROUGH TONIGHT/
A COLD FRONT IS CROSSING THROUGH THE AREA THIS MORNING AND
SHOULD BE LOCATED OFF THE COAST BY DAY BREAK. BEHIND THE FRONT,
RATHER STRONG ARCTIC HIGH PRESSURE LOCATED OVER THE GREAT LAKES
WILL BEGIN TO BUILD IN, ULTIMATELY SETTLING OVERHEAD TONIGHT.
ALOFT, AN IMPULSE WILL BE TRACKING ACROSS THE CENTRAL
APPALACHIANS TODAY, SHIFTING OFF THE COAST OF THE CHESAPEAKE
TONIGHT.
AS THE FRONT PASSES THROUGH THIS MORNING, NORTH-NORTHWEST WINDS
WILL STRENGTHEN AS COLD AIR ADVECTION BEGINS TO POUR INTO THE
REGION. WINDS WILL NOT BE OVERLY STRONG, BUT CONDITIONS WILL BE
BREEZY AT TIMES WITH GUSTS UP TO 30-35 MPH. THESE GUSTS SHOULD
PERSIST INTO THE EARLY AFTERNOON, BEFORE DIMINISHING AS HIGH
PRESSURE APPROACHES. AT THE SAME TIME, A WEAK SURFACE LOW
ASSOCIATED WITH THE AFORMENTIONED IMPULSE WILL TRACK OFF THE
COAST OF NORTH CAROLINA. THE IMPULSE WILL ENHANCE LIFT,
RESULTING IN PRECIPITATION DEVELOPING ACROSS THE CHESAPEAKE
REGION LATER THIS MORNING. WITH COLD AND DRY HIGH PRESSURE
SITUATED TO THE NORTH, THIS SHOULD SUPPRESS MOST PRECIP TO OUR
SOUTH. HOWEVER, THE NORTHERN PART OF THE PRECIPITATION SHIELD
COULD CLIP PORTIONS OF THE EASTERN SHORE OF MARYLAND AND
SOUTHERN DELAWARE RESULTING IN A PERIOD OF LIGHT SNOW THIS
AFTERNOON. ANY ACCUMULATIONS WOULD BE NEGLIGIBLE, POSSIBLY UP TO
A TENTH OR TWO. HIGH TEMPS WILL RANGE FROM THE MID 20S TO THE
MID 30S.
FOR TONIGHT, THE COLDEST NIGHT SO FAR THIS SEASON IS EXPECTED
AS COLD AIR ADVECTION CONTINUES. SURFACE HIGH PRESSURE WILL BE
LOCATED DIRECTLY OVERHEAD YIELDING LIGHT WINDS. SKIES WILL ALSO
GRADUALLY CLEAR FROM WEST TO EAST AS THE IMPULSE ALOFT DEPARTS
OVERNIGHT. THIS SHOULD ALLOW A PRETTY DECENT SET-UP FOR
RADIATIONAL COOLING TO OCCUR. OPTED TO BLEND IN SOME COLDER
FORECAST GUIDANCE AS A RESULT, WHERE LOW TEMPERATURES ARE
EXPECTED TO RANGE FROM THE SINGLE DIGITS ACROSS THE HIGHER
TERRAIN AND PORTIONS OF THE LEHIGH VALLEY, WITH MAINLY TEENS
EXPECTED ELSEWHERE. FORTUNATELY, WIND CHILLS WILL NOT BE FAR
REMOVED FROM THE ACTUAL AIR TEMPERATURE DUE TO LIGHT WINDS.
THESE TEMPERATURES ARE ANOMALOUSLY COLD FOR THIS TIME OF YEAR,
SO IT IS CERTAINLY POSSIBLE FOR A FEW CLIMATE SITES TO COME
WITHIN A FEW DEGREES OF THEIR RECORD VALUES. FOR MORE DETAILS,
REFER TO THE CLIMATE SECTION BELOW.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
ARCTIC HIGH PRESSURE WILL BE CENTERED OVER THE NORTHEAST ON
TUESDAY MORNING BEFORE SLIDING OFFSHORE TUESDAY AFTERNOON.
CONTINUED COLD, THOUGH MAYBE A FEW DEGREES WARMER COMPARED TO
TODAY, WITH HIGH TEMPERATURES SOME 10 TO 15 DEGREES BELOW
NORMAL, TOPPING OFF IN THE LOW 30S NORTH AND WEST OF THE FALL
LINE, AND IN THE MID TO UPPER 30S ACROSS SOUTHERN NEW JERSEY AND
DELMARVA. RETURN FLOW SETS UP TUESDAY BEHIND BEHIND THE
DEPARTING HIGH, AND AFTER TEMPERATURES FALL INTO THE UPPER 20S
TO LOW 30S IN THE EVENING, TEMPERATURES WILL HOLD STEADY OR
SLOWLY RISE INTO DAYBREAK.
A CLIPPER SYSTEM WILL DIVE INTO THE GREAT LAKES AND OHIO VALLEY
TUESDAY NIGHT AND WILL PASS THROUGH NORTHERN NEW YORK AND
NORTHERN NEW ENGLAND LATE WEDNESDAY, DEPARTING WEDNESDAY NIGHT.
A COLD FRONT WILL FOLLOW THROUGH BEHIND THE DEPARTING LOW
WEDNESDAY NIGHT, AND THEN COLD AIR ADVECTION WILL BE UNDERWAY.
TEMPERATURES RETURN CLOSER TO NORMAL ON WEDNESDAY WITH HIGHS
GENERALLY IN THE LOW TO MID 40S, AND POSSIBLY NEAR 50 IN
DELMARVA. PRECIPITATION DEVELOPS ACROSS MOST OF THE AREA, WITH
SNOW ACROSS THE SOUTHERN POCONOS, LEHIGH VALLEY, AND NORTHERN
NEW JERSEY, A WINTRY MIX RIGHT ALONG THE I-95 CORRIDOR, AND RAIN
ACROSS SOUTHERN NEW JERSEY AND DELMARVA, GENERALLY SOUTH OF THE
I-95 CORRIDOR. THE RAIN/SNOW LINE WILL GRADUALLY LIFT NORTH
THROUGHOUT THE DAY WEDNESDAY, WITH PRECIPITATION CHANGING TO
PLAIN RAIN AS FAR NORTH AS THE LEHIGH VALLEY, AND SNOW MAY MIX
WITH RAIN IN THE SOUTHERN POCONOS AND NORTHERN NEW JERSEY. IN
TERMS OF OVERALL SNOWFALL ACCUMULATION, CAN EXPECT GENERALLY 1
TO 2 INCHES IN THE HIGHER ELEVATIONS OF THE SOUTHERN POCONOS AND
NORTHERN NEW JERSEY, AND LESS THAN AN INCH DOWN TO THE FALL
LINE.
RAIN AND SNOW TAPERS OFF LATE TUESDAY. DRY TUESDAY NIGHT. LOWS
MAINLY IN THE MID AND UPPER 20S ACROSS NORTHERN AREAS AND IN THE
LOW TO MID 30S ELSEWHERE TUESDAY NIGHT.
LONG TERM /THURSDAY THROUGH SUNDAY/
SEVERAL REINFORCING COLD FRONTS WILL PASS THROUGH THE REGION
THROUGH THE END OF THE WEEK, WITH AN ARCTIC AIRMASS BUILDING
OVERHEAD THIS WEEKEND.
THURSDAY LOOKS TO BE MOSTLY DRY, THOUGH SOME FLURRIES MAY BE
POSSIBLE WITH THE PASSAGE OF A STRONG COLD FRONT. HIGHS RETURN
TO BELOW NORMAL LEVELS, GENERALLY IN THE UPPER 30S TO LOW 40S.
LOWS THURSDAY NIGHT DROP INTO THE 20S ACROSS MUCH OF THE AREA,
AND IN THE TEENS IN THE SOUTHERN POCONOS.
TEMPERATURES WILL DROP BY A FEW DEGREES ON FRIDAY, GENERALLY
TOPPING OFF IN THE UPPER 30S TO AROUND 40.
A CLIPPER-LIKE SYSTEM MAY PASS THROUGH THE REGION FRIDAY NIGHT
INTO SATURDAY MORNING. MODELS ARE NOT IN GOOD AGREEMENT IN TERMS
OF THE TIMING AND PLACEMENT OF THIS SYSTEM, AND LATEST RUNS ARE
TRENDING A BIT DRIER. WILL USE NBM GUIDANCE FOR THIS TIME WITH
POPS GENERALLY 40 TO 50 PERCENT, AND MOSTLY SNOW. AN ARCTIC
AIRMASS THEN BUILDS INTO THE REGION FOR THE WEEKEND. GUSTY WINDS
MAY DEVELOP ON SATURDAY AFTERNOON.
HIGHS ON SATURDAY AND SUNDAY WILL STRUGGLE TO REACH THE
FREEZING MARK FOR MOST OF THE AREA, THOUGH SHOULD BE IN THE MID
30S OR SO IN SOUTHERN DELMARVA AND ALONG THE JERSEY SHORE. HIGHS
WILL BE A FEW DEGREES COOLER ON SUNDAY COMPARED TO SATURDAY.
LOWS SATURDAY NIGHT WILL BE IN THE TEENS AND LOW 20S.
AVIATION /07Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 12Z...VFR WITH OCCASIONAL SCT/BKN CLOUDS AROUND
4000-5000 FEET. WEST WINDS WILL BECOME NORTHWEST AROUND 10 KT
WITH GUSTS UP TO 20 KT POSSIBLE FOLLOWING FRONTAL PASSAGE.
MODERATE-HIGH CONFIDENCE.
TODAY...VFR. BKN/OVC MID-HIGH CLOUDS. NORTH-NORTHEAST WINDS
AROUND 10-15 KT WITH GUSTS UP TO 20-25 KT, BEFORE BEGINNING TO
DIMINISH BY MID-LATE AFTERNOON. HIGH CONFIDENCE.
TONIGHT...VFR. BKN MID-HIGH CLOUDS EARLY, WILL GIVE WAY TO SKC
AFTER 06Z. NORTH-NORTHEAST WINDS AROUND 3 KT OR LESS, BECOMING
CALM AT TIMES. HIGH CONFIDENCE.
OUTLOOK...
TUESDAY THROUGH TUESDAY NIGHT...VFR. NSW.
WEDNESDAY THROUGH WEDNESDAY NIGHT...SUB-VFR IN RA AND/OR SN,
THOUGH SN IS MOST LIKELY AT KRDG/KABE. CONDS LIFT TO VFR
WEDNESDAY NIGHT.
THURSDAY THROUGH THURSDAY NIGHT...VFR. GUSTY WEST WINDS
POSSIBLE ON THURSDAY.
FRIDAY...SUB-VFR CONDS POSSIBLE LATE IN RA AND/OR SN.
MARINE
SMALL CRAFT ADVISORIES ARE IN EFFECT TODAY FOR ALL ATLANTIC
COASTAL WATERS AND THE DELAWARE BAY. SMALL CRAFT ADVISORIES
CONTINUE THROUGH TONIGHT FOR THE ATLANTIC COASTAL WATERS FROM
MANASQUAN INLET TO FENWICK ISLAND.
FOLLOWING A FRONTAL PASSAGE THIS MORNING, NORTHERLY WINDS
AROUND 10-15 KT WILL INCREASE TO AROUND 15-25 KT WITH WIND
GUSTS UP TO 30 KT THROUGH THIS AFTERNOON. WINDS WILL DIMINISH A
BIT TONIGHT TO AROUND 10-20 KT. SEAS AROUND 4-6 FEET. A PERIOD
OF LIGHT SNOW IS POSSIBLE TODAY SOUTH OF CAPE MAY, OTHERWISE,
FAIR WEATHER IS EXPECTED OUTSIDE OF SCA CONDITIONS.
OUTLOOK...
TUESDAY THROUGH TUESDAY NIGHT...SCA CONDS DEVELOP LATE TUESDAY
AND TUESDAY NIGHT. N WINDS TUESDAY MORNING TURN S IN THE
AFTERNOON. TUESDAY NIGHT, WINDS INCREASE TO 15 TO 20 KT WITH
GUSTS UP TO 25 KT.
WEDNESDAY THROUGH WEDNESDAY NIGHT...STRONG SCA CONDS LIKELY,
WITH GALE FORCE WINDS POSSIBLE. S TO SW WINDS 20 TO 30 KT. GUSTS
UP TO 35 KT POSSIBLE. WINDS TURN W WEDNESDAY NIGHT, GENERALLY
AT 20 TO 25 KT WITH GUSTS UP TO 30 KT.
THURSDAY THROUGH THURSDAY NIGHT...SCA CONDS THURSDAY SUBSIDE TO
SUB-SCA CRITERIA THURSDAY NIGHT. W WINDS 15 TO 20 KT WITH 25 TO
30 KT GUSTS, DIMINISHING TO 10 TO 15 KT WITH GUSTS TO 20 KT.
FRIDAY...SCA CONDS POSSIBLE. W WINDS 15 TO 20 KT.
CLIMATE
VERY COLD MONDAY NIGHT INTO TUESDAY MORNING. AT THIS POINT, WE
AREN'T FORECASTING TO BREAK ANY RECORD LOWS. BELOW ARE THE
RECORD LOWS FOR DECEMBER 9.
SITERECORD/YEAR
ALLENTOWN (ABE) 7/2002
AC AIRPORT (ACY) 6/1968
AC MARINA (55N) 5/1876
PHILADELPHIA (PHL) 6/1876
WILMINGTON (ILG) 13/1960
READING (RDG) 0/1989
TRENTON (TTN) 12/2002
MOUNT POCONO (MPO) -1/1902
GEORGETOWN (GED) 10/1976
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-
431-450.
SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ451.
SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ452>455.
SYNOPSIS...MPS
NEAR TERM...DESILVA
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...DESILVA/MPS
MARINE...DESILVA/MPS
CLIMATE...
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