661
FXUS61 KPHI 230514
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1214 AM EST MON DEC 23 2024
SYNOPSIS
ARCTIC HIGH PRESSURE CENTERED ACROSS SOUTHERN CANADA WILL MOVE TO
NEW ENGLAND BY MONDAY MORNING. THIS HIGH WEAKENS MONDAY NIGHT AND
THEN A MINOR LOW PRESSURE AREA PASSES THROUGH THE REGION TUESDAY
EVENING. HIGH PRESSURE RETURNS FOR WEDNESDAY AND REMAINS TO CLOSE
OUT THE WEEK. A NEW SYSTEM COULD APPROACH NEXT WEEKEND.
NEAR TERM /THROUGH TODAY/
FORECAST ON TRACK, SO NO SIGNIFICANT CHANGES WILL BE MADE TO
THE DATABASE.
MINOR TWEAKS TO TEMPERATURE GRIDS AS STRONG HIGH PRESSURE
MAINTAINS CONTROL OVER THE REGION. THE HIGH WILL GRADUALLY SLIDE
EASTWARD WITH ITS CENTER REACHING NEW ENGLAND LATER TONIGHT,
WITH THE WEAKEST PRESSURE GRADIENTS GRADUALLY ENVELOPING OUR
REGION. WITH LIGHT WINDS AND CLEAR SKIES, AND SOME SNOW PACK
ESPECIALLY NORTH OF PHILLY, EXPECT TONIGHT TO ALSO BE A
CONTENDER FOR THE COLDEST TEMPERATURE OF 2024, WITH WIDESPREAD
SINGLE DIGITS, TEENS IN THE URBAN CENTERS, IMMEDIATE COAST AND
DELMARVA, BUT NEAR ZERO IN THE POCONOS. AREAS WITH SNOW PACK MAY
IN FACT END UP DIPPING A BIT BELOW OUR CURRENT FORECAST, SO
WILL NEED TO WATCH TRENDS EARLY THIS EVENING. WITH MINIMAL
WINDS, HOWEVER, NO FURTHER COLD WEATHER ADVISORIES ARE WARRANTED
AS WIND CHILLS SHOULD BE CLOSE TO ACTUAL TEMPERATURES.
THE HIGH SLIDES ITS WAY FURTHER EAST ON MONDAY. WHILE SKIES START
OUT CLEAR, INCREASING HIGH CLOUDS WILL TURN THE SKY A BIT LESS
BLUE DURING THE AFTERNOON. WINDS WILL GRADUALLY TURN SOUTH TO
SOUTHEAST, BUT REMAIN FAIRLY LIGHT. STILL, WARM ADVECTION ALOFT
SHOULD BE ENOUGH TO SEND HIGHS AT LEAST A FEW DEGREES ABOVE
TODAY'S READINGS, WITH HIGHS BACK ABOVE FREEZING ALONG THE COAST
AND IN MUCH OF THE DELMARVA, NEAR 30 IN PHILLY, AND 20S FURTHER
NORTH.
SHORT TERM /TONIGHT THROUGH WEDNESDAY/
FAIR WEATHER WILL REMAIN FOR THE FIRST PART OF MONDAY NIGHT. AFTER
THAT, A FAST MOVING UPPER TROUGH AND WEAK LOW PRESSURE SYSTEM WILL
MOVE NORTH OF OUR REGION. THIS FEATURE WILL BRING IN CLOUDS ALONG
WITH PRECIP TO THE (MOSTLY) WESTERN AND NORTHERN COUNTIES. THE
CHANCES FOR PRECIP WILL CARRY INTO TUE MORNING AS WELL, BIT OVERALL
THE SYSTEM IS RATHER MOISTURE STARVED AND THE DYNAMICS ARE NOT
IMPRESSIVE. P-TYPE FAVORS SNOW WITH THE EVENT OCCURRING DURING THE
OVERNIGHT. ANY ACCUMULATIONS WILL BE ONLY A FEW TENTHS OF AN INCH.
LOWS OVERNIGHT WILL BE IN THE 20S.
FOLLOWING THE WEAK LOW, MORE HIGH PRESSURE BUILDS IN FOR TUE NIGHT
AND WED. A PERIOD OF FAIR WEATHER IS EXPECTED BUT TEMPERATURES WILL
STRUGGLE TO RETURN TO NORMAL. LOWS TUE NIGHT WILL AGAIN BE MOSTLY
IN THE 20S. FOR WEDNESDAY, READINGS WILL TOP OUT IN THE MID/UPPER
30S FOR THE NW (OF I-95) AREAS WHILE LOW 40S ARE POSSIBLE FOR SOUTH
NJ AND DELMARVA. THESE TEMPS WILL BE AROUND 5 DEGREES BELOW NORMAL.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
TOWARDS THE END OF NEXT WEEK AND INTO THE FOLLOWING WEEKEND, WE ARE
LOOKING AT A PERIOD WHERE TEMPERATURES WILL RETURN BACK TO NORMAL
(THURSDAY) AND THEN ABOVE NORMAL. ANOTHER LARGE HIGH PRESSURE SYSTEM
WILL BE ACROSS EASTERN CANADA AND SINCE OUR REGION WILL BE ON THE
SOUTH SIDE OF THIS FEATURE, THE CLOCKWISE FLOW AROUND THE HIGH WILL
BRING A E OR SE FLOW FROM THE OCEAN. A FLOW WHICH PROMOTES DRIVING
THE COLD AIR AWAY, BUT ALSO BRINGING MORE MOISTURE TOO. WE'LL HAVE
HIGHS IN THE 40S FRIDAY AND SATURDAY WITH SOME 30S ACROSS THE
SOUTHERN POCONOS. BY SATURDAY, SOME LOW 50S ARE POSSIBLE FOR
DELMARVA AND SOUTH NJ.
SINCE HIGH PRESSURE WILL BE ACROSS THE AREA FOR MOST OF THE LONG
TERM THE THU/FRI PERIODS LOOK DRY ATTM. THERE IS A SMALL CHANCE FOR
SOME LIGHT SNOW WED NIGHT INTO THE PREDAWN THU ACROSS OUR EXTREME SW
AREAS (SOUTHERN BERKS AND CHESTER COUNTIES). IT'S POSSIBLE THAT
THE TEMPERATURE PROFILES MAY SUPPORT SOME FREEZING P-TYPES TOO.
WE'LL HAVE SNOW IN WITH SLIGHT CHANCE POPS FOR NOW.
THE RETURN MOISTURE AND AN APPROACHING WEAK SYSTEM LATER SAT COULD
BRING HIGHER CHANCES FOR RAINS (MOSTLY) SAT NIGHT AND INTO NEXT
SUNDAY. WE'LL CARRY SOME CHANCE POPS FOR THOSE PERIODS ATTM. THE
PREVIOUS MODEL RUNS WERE SHYING AWAY FROM PRECIP ON SAT. BUT THE
MORE RECENT RUNS HAVE BROUGHT IT BACK, WE'LL START SAT. WITH SLIGHT
CHANCE(20) POPS AND THEN BUMP TO CHANCE FOR THE AFTERNOON.
AVIATION /05Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. N-NE WINDS AROUND 5 KT, BECOMING NEARLY CALM
LATE. HIGH CONFIDENCE.
MONDAY...VFR. LOCALLY CALM WINDS BECOMING SOUTH TO SOUTHEAST
5-10 KTS IN THE AFTERNOON. HIGH CONFIDENCE.
OUTLOOK...
MONDAY NIGHT/TUE MORNING... VFR DURING THE EVENING WITH INCREASING
CLOUDS. LIGHT SNOW DEVELOPING WITH LOWER CIGS/VSBYS POSSIBLE OVERNIGHT
MOSTLY (KRDG/KABE) BUT ALSO POSSIBLE FOR THE DELAWARE VALLEY SITES
AS WELL. MEDIUM CONFID.
TUE AFTERNOON/NIGHT THRU WED... VFR DECREASING CLOUDS.
WED NIGHT... VFR MOST AREAS THRU THE NIGHT, BUT A PERIOD OF LOWER
CONDITIONS AND -SN POSSIBLE KRDG AND PERHAPS CLOSE TO KRDG/KILG OR
KPHL TOWARDS DAWN. MEDIUM CONFID OVERALL.
THU/FRI... VFR EXPECTED.
MARINE
NORTHWEST WINDS AROUND 10-15 KTS GRADUALLY DIMINISHING THROUGH TONIGHT
WITH SEAS SUBSIDING TO 1-3 FEET. WINDS BECOME SOUTHEASTERLY 5-10
KTS MONDAY WITH NO INCREASE IN SEAS JUST YET. FAIR WEATHER.
OUTLOOK...
MONDAY NIGHT THROUGH THURSDAY...SUB-SCA CONDITIONS EXPECTED.
CLIMATE
NEAR RECORD BREAKING COLD TEMPERATURES ARE FORECAST TODAY AND TONIGHT.
RECORDS FOR OUR CLIMATE SITES ARE LISTED BELOW:
RECORD COLDEST HIGH TEMPERATURES
DECEMBER 22
SITE RECORD/YEAR
ALLENTOWN (ABE) 16/1989
AC AIRPORT (ACY) 18/1989
AC MARINA (55N) 19/1989
GEORGETOWN (GED) 28/1980
MOUNT POCONO (MPO) 11/1989
PHILADELPHIA (PHL) 19/1989
READING (RDG) 19/1989
TRENTON (TTN) 16/1989
WILMINGTON (ILG) 17/1989
RECORD COLDEST LOW TEMPERATURES
DECEMBER 23
SITE RECORD/YEAR
ALLENTOWN (ABE) -3/1960
AC AIRPORT (ACY) 1/1989
AC MARINA (55N) 6/1989
GEORGETOWN (GED) 3/1989
MOUNT POCONO (MPO) -6/1989
PHILADELPHIA (PHL) 7/1989
READING (RDG) 2/1989
TRENTON (TTN) 2/1989
WILMINGTON (ILG) 4/1989
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...MPS/RCM
NEAR TERM...AKL/MPS/RCM
SHORT TERM...OHARA
LONG TERM...OHARA
AVIATION...AKL/MPS/OHARA/RCM
MARINE...OHARA/RCM
CLIMATE...
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