690
FXUS61 KPHI 282324
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
624 PM EST WED JAN 28 2026
WHAT HAS CHANGED
THE COLD WEATHER ADVISORY REMAINS IN EFFECT THROUGH THURSDAY
MORNING.
REGARDING THE WEEKEND STORM POTENTIAL, THERE HAVE CONTINUED BE SOME
FLUCTUATIONS BACK AND FORTH IN FORECAST GUIDANCE REGARDING THE STORM
TRACK BUT GENERALLY SPEAKING NO MAJOR CHANGES IN OVERALL FORECAST
THINKING. THERE WILL VERY LIKELY BE AT LEAST SOME IMPACTS ACROSS
PORTIONS OF THE AREA THIS WEEKEND FROM A POTENTIALLY MAJOR COASTAL
STORM. IMPACTS COULD BE SIGNIFICANT, ESPECIALLY NEAR THE COAST.
KEY MESSAGES
1. A PROLONGED STRETCH OF DANGEROUS (AND POTENTIALLY RECORD-
SETTING) COLD SETTLES OVER THE REGION THIS WEEK INTO THE
WEEKEND, WITH DAYTIME HIGHS WELL BELOW FREEZING AND OVERNIGHT
LOWS IN THE SINGLE DIGITS, RESULTING IN BELOW ZERO WIND CHILLS.
2. A RAPIDLY DEEPENING STORM IS EXPECTED TO DEVELOP OFF THE EAST
COAST THIS WEEKEND. WHILE CONFIDENCE IN SPECIFIC FORECAST DETAILS
STILL REMAINS LOW, THE STORM COULD BRING AT LEAST PORTIONS OF THE
AREA MODERATE TO SIGNIFICANT IMPACTS FROM SNOW, STRONG WINDS, AND
COASTAL FLOODING SATURDAY NIGHT INTO SUNDAY.
DISCUSSION
KEY MESSAGE 1....A PROLONGED STRETCH OF DANGEROUS (AND
POTENTIALLY RECORD-SETTING) COLD SETTLES OVER THE REGION THIS
WEEK AND INTO THE WEEKEND, WITH DAYTIME HIGHS WELL BELOW
FREEZING AND OVERNIGHT LOWS IN THE SINGLE DIGITS, RESULTING IN
BELOW ZERO WIND CHILLS.
SURFACE HIGH PRESSURE MOSTLY DOMINATES THROUGH THURSDAY. AN
UPPER TROUGH WILL PASS THROUGH THE REGION LATE THIS AFTERNOON
AND EARLY THIS EVENING, AND THIS WILL BRING A REINFORCING SHOT
OF ARCTIC AIR INTO THE REGION LATE TONIGHT THROUGH THURSDAY. THE
BASE OF THIS TROUGH WILL PASS THROUGH THE DELMARVA PENINSULA AND
MID-ATLANTIC WITH RATHER STRONG SHORTWAVE ENERGY. AS A RESULT,
ISOLATED SNOW SHOWERS WITH MINIMAL SNOW ACCUMULATION WILL
DEVELOP OVER THE EASTERN SHORES OF MARYLAND AND SOUTHERN
DELAWARE WITH ITS PASSAGE. WILL BUMP UP POPS TO SLIGHT CHANCE
FOR SEVERAL HOURS THIS EVENING. FOR THE REST OF THE AREA, SOME
SCATTERED FLURRIES ARE POSSIBLE DUE TO OTHER SHORTWAVES.
LOWS TONIGHT WILL DROP INTO THE SINGLE DIGITS FOR MOST OF THE
AREA AND AS LOW AS 5 BELOW ZERO FOR THE SOUTHERN POCONOS, FAR
NORTHWEST NEW JERSEY, AND THE LEHIGH VALLEY. MINIMUM WIND CHILLS
LATE TONIGHT THROUGH THURSDAY MORNING WILL RANGE FROM AS LOW AS
10 BELOW ZERO TO 15 BELOW ZERO. THE COLD WEATHER ADVISORY
REMAINS IN EFFECT THROUGH THURSDAY MORNING. THERE MAY BE SOME
SPOTS IN OUTLYING AREAS WHERE WINDS DROP TO AROUND 5 MPH, AND
THIS WILL ALLOW FOR RADIATIONAL COOLING WHICH COULD RESULT IN
EVEN COLDER LOCALIZED TEMPERATURES.
MOSTLY SUNNY, BREEZY, AND COLD ON THURSDAY WITH HIGHS IN THE
TEENS AND LOW 20S.
THE VERY COLD TEMPERATURES AND BITTER WIND CHILLS WILL PERSIST THE
REMAINDER OF THE WEEK AND BEYOND. THIS WILL OCCUR DUE TO A DEEP
UPPER LEVEL TROUGH CENTERED OVER EASTERN CANADA WITH REPEATED RE-
ENFORCING SHOTS OF ARCTIC AIR SWINGING IN FROM THE NORTH AND WEST
AROUND THIS FEATURE. FOR THURSDAY NIGHT AND FRIDAY NIGHT, EXPECT
MORNING LOW TEMPERATURES IN THE SINGLE DIGITS TO NEGATIVE SINGLE
DIGITS WITH EACH MORNING ACTUALLY LOOKING SLIGHTLY COLDER THAN THE
PREVIOUS ONE DUE TO THESE RE- ENFORCING SHOTS OF ARCTIC AIR. MORE
IMPORTANTLY, THERE WILL BE AT LEAST SOME WINDS THROUGH MOST OF THIS
PERIOD WITH EARLY MORNING WIND CHILLS STILL EXPECTED TO BE SUB-ZERO
REGION WIDE WITH NEGATIVE TEENS N/W OF THE I-95 CORRIDOR TO EVEN
AROUND -20 IN THE SOUTHERN POCONOS. SOME MODERATION IN TEMPERATURES
MAY OCCUR SUNDAY INTO EARLY NEXT WEEK HOWEVER TEMPERATURES STILL
LOOK TO BE WELL BELOW AVERAGE.
OVERALL, IT IS EXCEEDINGLY RARE TO GET THIS COMBINATION OF LENGTH
AND MAGNITUDE OF AN ARCTIC AIRMASS FOR THIS AREA AND IT SHOULD BE
TAKEN SERIOUSLY FOR THOSE WHO HAVE TO VENTURE OUT IN THE COLD FOR
EXTENDED PERIODS OF TIME.
KEY MESSAGE 2...A RAPIDLY DEEPENING STORM IS EXPECTED TO DEVELOP OFF THE EAST
COAST THIS WEEKEND. WHILE CONFIDENCE IN SPECIFIC FORECAST DETAILS
STILL REMAINS LOW, THE STORM COULD BRING AT LEAST PORTIONS OF THE
AREA MODERATE TO SIGNIFICANT IMPACTS FROM SNOW, STRONG WINDS, AND
COASTAL FLOODING SATURDAY NIGHT INTO SUNDAY.
FORECAST MODELS CONTINUE TO FORECAST CYCLOGENSIS OCCURRING BEGINNING
SATURDAY OFF THE SOUTHEAST COAST WITH RAPIDLY DEEPENING LOW PRESSURE
DEPICTED TO THEN MOVE NORTH AND EAST SATURDAY NIGHT THROUGH SUNDAY.
THIS WILL OCCUR DUE TO A POTENT UPPER LEVEL DISTURBANCE PIVOTING
AROUND THE BASE OF THE LONG WAVE TROUGH OVER THE EAST INTERACTING
WITH THE STRONG BAROCLINIC ZONE ALONG THE COAST.
IN TERMS OF IMPACTS TO OUR FORECAST AREA, THIS HINGES ON THE
EXACT TRACK THE STORM TAKES WHICH STILL REMAINS UNCERTAIN AT
THIS TIME. GENERALLY SPEAKING, THE LATEST 12Z DETERMINISTIC
GUIDANCE HAS OUR FORECAST AREA NEAR THE N/W FRINGE OF THE
STORM'S PRECIP SHIELD. THE GFS HAS SHIFTED SLIGHTLY FARTHER S/E
WITH THE STORM TRACK AND PRECIP SHIELD COMPARED TO THE 0Z RUN
WHILE THE ECMWF HAS SHIFTED A BIT WEST. THERE ALSO CONTINUES TO
BE SPREAD AMONG THE ENSEMBLES. ONE THING THAT'S INTERESTING TO
NOTE THOUGH IS THAT THE RGEM (THE CANADIAN MODEL) APPEARS TO BE
SUPPORTING A TRACK NEAR OR A BIT WEST OF THE MODEL CONSENSUS
BASED ON ITS PLACEMENT OF UPPER LEVEL FEATURES AT THE END OF
ITS RUN AT 84 HOURS OUT (7PM SATURDAY EVENING). THIS MODEL
GENERALLY DOES VERY WELL WITH THESE TYPES OF LARGE SCALE WINTER
SYSTEMS.
POTENTIAL STORM IMPACTS INCLUDE NOT JUST HEAVY PRECIPITATION BUT
ALSO STRONG WINDS AND COASTAL FLOODING AS THE STORM WILL HAVE A
TIGHT PRESSURE GRADIENT WITH A VERY STRONG WIND FIELD. TIMING WISE,
THE EARLIEST THIS WOULD ARRIVE IS LATE DAY SATURDAY WITH THE BRUNT
OF THE STORM OCCURING SATURDAY NIGHT INTO SUNDAY IF WE GET IT. GIVEN
THE VERY COLD TEMPERATURES IN PLACE BOTH AT THE SURFACE AND ALOFT,
ALL SNOW IS STRONGLY FAVORED IN TERMS OF PRECIP TYPE.
THE LATEST NBM PROBABILISTIC DATA HAS TRENDED BACK UP A BIT. FOR
SNOW AMOUNTS GREATER THAN 2 INCHES (PLOWABLE), THE RANGE IS FROM
AROUND 60-70 PERCENT NEAR THE COAST TO 40-50 PERCENT NEAR THE I-95
CORRIDOR WITH LOWER PROBABILITIES N/W OF THE URBAN CORRIDOR. FOR 6+
INCHES, THESE PROBS ARE AROUND 30-40 PERCENT NEAR I-95 UP TO 50-60
PERCENT NEAR THE COAST. THESE PROBABILITIES OVERALL SEEM REASONABLE
BUT IT'S WORTH NOTHING THAT THE PROBABILITY GREATER THAN 2 INCH
NUMBERS ARE NOT THAT DIFFERENT THAN THE PROBABILITY GREATER
THAN 6 INCH NUMBERS. THIS IS LIKELY DUE TO THE FACT THAT MUCH OF
THE FORECAST GUIDANCE DEPICTS A SHARP GRADIENT IN QPF/SNOW
AMOUNTS WHICH IS PRETTY COMMON ON THE N/W SIDE OF THE TYPE OF
STORMS.
REGARDLESS OF SNOW AMOUNTS, WE HAVE GROWING CONFIDENCE THE STORM SHOULD
AT LEAST TRACK CLOSE ENOUGH TO BRING THE AREA INCREASING WINDS
SATURDAY NIGHT INTO SUNDAY. OUR CURRENT FORECAST HAS N/NE WINDS
FORECAST TO BE 15 TO 25 GUSTING 25 TO 35 MPH INLAND SUNDAY WITH
WINDS 25 TO 35 GUSTING UP TO 50 MPH ALONG THE COAST. WINDS COULD
EVEN END UP A BIT STRONGER THAN THIS IF A MORE N/W TRACK WITH
THE STORM OCCURS. THIS COULD LEAD TO SOME DAMAGE AND POWER
OUTAGES AND MAY ALSO HELP CAUSE WATER TO REALLY PILE UP ALONG
THE COAST LEADING TO THE COASTAL FLOODING CONCERNS IF WINDS END
MORE TOWARDS THE NE VS. THE NORTH.
BY SUNDAY EVENING, THE STORM SHOULD BE RAPIDLY PULLING AWAY TO THE
NORTHEAST WITH GENERALLY TRANQUIL BUT COLD WEATHER FOR EARLY NEXT
WEEK.
OVERALL THIS REMAINS A VERY CHALLENGING FORECAST BECAUSE EVEN THOUGH
THERE'S A BIT LESS DISPERSION IN THE FORECAST MODELS COMPARED TO
YESTERDAY, IT IS STILL VERY HARD TO RULE OUT A MORE DIRECT HIT OR A
COMPLETE MISS IN TERMS OF SNOWFALL SINCE WE'LL LIKELY BE NEAR THE
N/W EDGE OF THE PRECIP SHIELD AS DESCRIBED ABOVE. THIS MEANS A
RELATIVELY SMALL SHIFT OF 50-100 MILES IN STORM TRACK WILL HAVE
LARGE IMPLICATIONS IN TERMS OF IMPACTS.
AVIATION /00Z THURSDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS...
TONIGHT...VFR. WEST-NORTHWEST WIND 5-10 KT. A FEW GUSTS 15-20
KT ARE POSSIBLE THROUGH ABOUT 03Z. HIGH CONFIDENCE.
WEDNESDAY...VFR. NORTHWEST WIND INCREASING TO 10-15 KT WITH
GUSTS 20-25 KT AFTER 15Z. HIGH CONFIDENCE.
OUTLOOK...
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...GENERALLY VFR.
SATURDAY THROUGH SUNDAY...POTENTIAL FOR INCREASING WINDS AND SUB VFR
CONDITIONS ARRIVING LATE DAY SATURDAY CONTINUING INTO SUNDAY
DEPENDING ON TRACK OF COASTAL STORM. HIGHEST CHANCE OF IMPACTS KACY,
LOWEST KRDG, INTERMEDIATE AT KPHL AND KPNE.
SUNDAY NIGHT THROUGH MONDAY...ANY RESTRICTIONS THAT OCCUR SUNDAY
DURING THE DAY QUICK IMPROVING TO VFR THROUGH THE EVENING WITH
VFR PREVAILING THROUGH MONDAY.
MARINE
SUB-SMALL CRAFT ADVISORY CONDITIONS INTO THIS EVENING. A COLD
FRONT PASSES THROUGH THE WATERS BY MIDNIGHT TONIGHT, THEN NW
WINDS RAMP UP TO 15 TO 20 KT WITH 25 TO 30 KT GUSTS ON DELAWARE
BAY AND THE OCEAN WATERS SOUTH OF THE GREAT EGG INLET AND WILL
LAST THROUGH THURSDAY. SMALL CRAFT ADVISORIES ARE NOW IN EFFECT
FOR THOSE WATERS FOR TONIGHT THROUGH THURSDAY. NORTH OF THE
GREAT EGG INLET, WINDS WILL GENERALLY AVERAGE 10 TO 15 KT WITH
GUSTS UP TO 20 KT, SO NO SCA WILL BE ISSUED AT THIS TIME. A
FREEZING SPRAY ADVISORY IS ALSO IN EFFECT FOR THE WATERS WHERE A
SCA IS IN EFFECT.
OUTLOOK...
MARGINAL SCA CONDITIONS WILL BE POSSIBLE THURSDAY NIGHT INTO EARLY
FRIDAY BEFORE WINDS SUBSIDE FOR A TIME BY LATER FRIDAY THROUGH EARLY
SATURDAY
LATE SATURDAY THROUGH SUNDAY...WINDS RAMP UP DUE TO COASTAL STORM
WITH GALE FORCE WINDS PROBABLE AND EVEN THE POTENTIAL FOR STORM
FORCE WINDS, ESPECIALLY OVER OUR OCEAN ZONES. SEAS COULD EXCEED 10
FEET SUNDAY.
SUNDAY NIGHT THROUGH MONDAY...WINDS/SEAS WILL TREND DOWN THROUGH
THIS PERIOD BUT THERE COULD STILL BE GALE FORCE WINDS INTO EARLY
MONDAY WITH CONDITIONS LIKELY TO STILL BE AT SMALL CRAFT ADVISORY
LEVELS EVEN LATE DAY MONDAY.
CLIMATE
POTENTIALLY RECORD-BREAKING COLD IS EXPECTED LATER THIS WEEK
WITH A CHANCE FOR SOME OF OUR CLIMATE SITES TO SET RECORD LOW
TEMPERATURES AND RECORD LOW MAXIMUM TEMPERATURES.
RECORD LOW TEMPERATURES AND RECORD LOW HIGH TEMPERATURES FOR:
JANUARY 29
SITE LOW/YEAR LOW MAX TEMPERATURE/YEAR
ABE -9/1963 12/1977
ACY 0/1966 18/1977
PHL -5/1963 18/1977
ILG 0/1961 18/1966
RDG -4/1987 18/1902
TTN 0/1873 17/1977
MPO -21/1988 7/1966
GED -6/1966 18/1966
55N 7/1966 22/2014
JANUARY 30
SITE LOW/YEAR LOW MAX TEMPERATURE/YEAR
ABE -5/1928 14/1934
ACY -3/2014 19/1965
PHL 7/2019 18/1965
ILG 3/2014 16/1934
RDG -1/2014 9/2013
TTN 4/2014 12/1873
MPO -15/1965 7/1934
GED -5/2014 24/2010
55N 8/1935 18/1934
JANUARY 31
SITE LOW/YEAR LOW MAX TEMPERATURE/YEAR
ABE -9/1948 14/2019
ACY 0/1948 20/2019
PHL 3/1948 18/2019
ILG 3/1948 19/2019
RDG -5/2019 14/2019
TTN -1/1920 16/2019
MPO -15/1908 4/2019
GED 1/1948 23/2019
55N 4/1948 19/2019
NOT ALL RECORDS WILL BE CHALLENGED OR BROKEN, BUT SOME
COULD FALL OVER THE COMING DAYS AND NIGHTS.
PHI WATCHES/WARNINGS/ADVISORIES
PA...COLD WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR PAZ054-055-
060>062-070-071-101>106.
NJ...COLD WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR NJZ001-
007>010-012>027.
DE...COLD WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR DEZ001>004.
MD...COLD WEATHER ADVISORY UNTIL 10 AM EST THURSDAY FOR MDZ012-015-
019-020.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST
THURSDAY FOR ANZ430-431-452>455.
FREEZING SPRAY ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST
THURSDAY FOR ANZ430-431-452>455.
DISCUSSION...FITZSIMMONS/MPS/OHARA
AVIATION...COOPER/FITZSIMMONS/MPS
MARINE...FITZSIMMONS/MPS
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