885
FXUS61 KPHI 241123
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
623 AM EST SAT JAN 24 2026
WHAT HAS CHANGED
SNOWFALL AMOUNTS WERE REDUCED SLIGHTLY, MAINLY SOUTH AND EAST OF
THE I-95 CORRIDOR AS CONFIDENCE HAS INCREASED IN MIXING
OCCURRING. IMPACTS ARE UNCHANGED AS THE COMBINATION OF
SNOW/SLEET/FREEZING RAIN WILL RESULT IN MAJOR DISRUPTIONS OVER
THE AREA.
THE NARROW CORRIDOR OF HIGHEST ICE ACCUMULATIONS HAS SHIFTED
SOUTHEAST, NOW FOCUSED OVER SOUTH JERSEY, CENTRAL DELAWARE, AND
THE EASTERN SHORE OF MARYLAND.
KEY MESSAGES
1. DANGEROUS COLD CONTINUES THROUGH THIS MORNING WITH WIND CHILLS
BELOW ZERO FOR MOST. WIND CHILLS AS LOW AS -22 EXPECTED TO CONTINUE
IN THE POCONOS.
2. A MAJOR WINTER STORM IS EXPECTED TO IMPACT THE AREA, BEGINNING
TONIGHT AND CONTINUING THROUGH MONDAY MORNING. THIS STORM WILL BRING
SIGNIFICANT SNOW AND ICE ACCUMULATIONS TO THE ENTIRE AREA, RESULTING
IN MAJOR DISRUPTIONS.
3. ARCTIC AIR REMAINS IN PLACE THROUGH THE UPCOMING WEEK WITH
TEMPERATURES BELOW FREEZING INTO FRIDAY.
DISCUSSION
KEY MESSAGE 1...DANGEROUS COLD CONTINUES THROUGH THIS MORNING WITH
WIND CHILLS BELOW ZERO FOR MOST. WIND CHILLS AS LOW AS -22 EXPECTED
TO CONTINUE IN THE POCONOS.
IN THE WAKE OF A STRONG ARCTIC FRONT, VERY COLD TEMPERATURES HAVE
SETTLED OVER THE AREA. WINDS WERE GUSTING UPWARDS OF 40-45 MPH
EARLIER, BUT HAVE DROPPED TO AROUND 25-35 MPH OR SO. FORECAST IS
WORKING OUT WELL WITH WIND CHILLS FROM 0 TO -10 BEING OBSERVED
ACROSS MOST OF THE AREA. THE SOUTHERN POCONOS, WHERE THE EXTREME
COLD WARNING IS IN PLACE, HAVE SEEN WIND CHILLS BETWEEN -18 AND -22
FOR MOST OF THE NIGHT. WIND CHILLS SHOULD GENERALLY STAY IN THIS
RANGE AS TEMPERATURES CONTINUE TO FALL BUT WINDS DIMINISH. AS A
RESULT, NO CHANGES ARE NEEDED TO THE COLD WEATHER HEADLINES. THE
EXTREME COLD WARNING FOR THE POCONOS AND COLD WEATHER ADVISORY
ELSEWHERE REMAINS IN EFFECT THROUGH 10 AM.
AHEAD OF THE STORM, IT WILL BE BITTERLY COLD TODAY, WITH HIGHS ONLY
TOPPING OUT IN THE UPPER TEENS/LOW 20S. THE POCONOS MAY NOT EVEN
MAKE IT OUT OF THE SINGLE DIGITS.
KEY MESSAGE 2... A MAJOR WINTER STORM IS EXPECTED TO IMPACT THE
AREA, BEGINNING TONIGHT AND CONTINUING THROUGH MONDAY MORNING. THIS
STORM WILL BRING SIGNIFICANT SNOW AND ICE ACCUMULATIONS TO THE
ENTIRE AREA, RESULTING IN MAJOR DISRUPTIONS.
A SIGNIFICANT WINTER STORM THAT HAS RESULTED IN CONTINUOUS WINTER
STORM WARNINGS FROM ARIZONA TO MAINE FINALLY GETS TO OUR AREA,
BEGINNING TONIGHT. SNOWFALL BEGINS AFTER 1 AM FROM SOUTHWEST TO
NORTHEAST AS LOW PRESSURE APPROACHES FROM THE SOUTHWEST. AS SNOW
SPREADS INTO THE REGION, A SECONDARY AREA OF LOW PRESSURE BEGINS TO
FORM NEAR THE OUTER BANKS, MOVING UP THE COAST AS SUNDAY GOES ON.
THE TRACK OF THIS SECONDARY LOW LOOKS TO BE INSIDE THE BENCHMARK (40
N, 70 W), WHICH USUALLY RESULTS IN A MIXED PRECIPITATION STORM FOR
OUR AREA AND A FORECASTING HEADACHE. THAT IS THE CASE HERE. HOWEVER,
CONFIDENCE IS INCREASING IN THIS FORECAST.
THE MAIN CHANGES FROM THE DAYTIME PACKAGE WERE CUTTING SNOW TOTALS
SOUTH AND EAST OF I-95 AS THE TREND HAS BEEN A TOUCH WEST WITH THE
TRACK OF THE LOW, RESULTING IN MORE OF A SLEET/FREEZING RAIN MIX AND
EVEN PLAIN RAIN ALONG THE COAST. SNOW TOTALS WERE SLIGHTLY REDUCED
FOR OTHER AREAS AS WELL, BUT NOT BY MUCH. VERY IMPORTANT TO STRESS
THAT WHILE SNOWFALL TOTALS HAVE BEEN REDUCED SLIGHTLY, THE IMPACTS
REMAIN THE SAME. THE COMBINATION OF SNOW, SLEET, AND FREEZING RAIN
WILL RESULT IN MAJOR IMPACTS AND THAT THINKING HAS NOT CHANGED FOR
DAYS NOW.
SNOWFALL ENVELOPS THE WHOLE REGION BY DAYBREAK SUNDAY. AN AREA OF
STRONG MID-LEVEL FRONTOGENESIS WILL LIFT NORTHWARD AS THE MORNING
GOES ON, AND ALL AREAS SHOULD SEE A VERY GOOD THUMP OF SNOW BEFORE A
CHANGEOVER TO SLEET OR FREEZING RAIN. SNOWFALL RATES OVER 1" PER
HOUR ARE LIKELY (60-80%), MAINLY FOR NEW JERSEY AND PENNSYLVANIA
TOMORROW MORNING INTO THE EARLY AFTERNOON, WITH EVEN A LOW CHANCE
(20%) FOR RATES OVER 2" PER HOUR. AS THE DAY PROGRESSES, A WARM NOSE
ALOFT MOVES IN FROM THE SOUTHEAST. AFTER LOOKING AT SOME MODEL
SOUNDINGS, CURRENTLY THINKING THE MIX LINE GETS RIGHT TO ABOUT
READING AND ALLENTOWN IN PA AND RIGHT UP TO I-78 IN NJ. SNOWFALL
AMOUNTS WILL BE DEPENDENT ON HOW FAST OR SLOW THAT WARM AIR
ADVECTION ALOFT IS. GIVEN HOW GOOD THE NAM IS IN THESE CASES, THE
FORECAST GENERALLY RELIES ON THAT TEMPERATURE PROFILE, BUT NOT AS
AGGRESSIVE, WITH THE THINKING THAT THE IMPRESSIVE RATES BEFORE THE
CHANGEOVER CAN HOLD BACK THE WARM NOSE ALOFT. IT WILL BE VERY
INTERESTING TO SEE HOW THIS PLAYS OUT TOMORROW MORNING. IMPORTANT TO
NOTE THAT GUIDANCE GENERALLY UNDERESTIMATED THE STRENGTH OF THE COLD
AIRMASS THIS MORNING. DOES IT MATTER? THAT IS THE QUESTION THAT WILL
BE FIGURED OUT VIA MESOANALYSIS AS THE EVENT BEGINS.
AT ONSET, SNOW RATIOS WILL BE AROUND 15-18:1, DECREASING TO AROUND 7-
10:1 BY THE EARLY AFTERNOON (AND EVEN LOWER WHERE SLEET BEGINS) AS
WARMER AIR ALOFT MOVES IN. THIS WILL RESULT IN A FLUFFY SNOW
TEXTURE. HOWEVER, ADD IN SLEET AND/OR MEASURABLE ICE ON TOP OF THAT?
IT COULD BE VERY DIFFICULT TO REMOVE FROM ROADS, DRIVEWAYS, AND
SIDEWALKS. THIS IS MAINLY WHY WE ARE STRESSING MAJOR IMPACTS,
REGARDLESS OF SNOW TOTALS. THERE IS HIGH CONFIDENCE IN AT LEAST 6"
OF SNOW, AND SLEET/ICE ON TOP OF THAT WILL JUST EXACERBATE IMPACTS
(AND MOST AREAS ARE HIGHLY PROBABLE TO SEE MORE THAN 6").
IN TERMS OF SPECIFIC AMOUNTS, THE FORECAST HAS 12-16" WITH LOCALIZED
AMOUNTS UP TO 18" FOR THE I-78 CORRIDOR ON NORTH. THESE AREAS SHOULD
PRIMARILY STAY SNOW. FROM NEW CASTLE COUNTY, DE OUT TO LBI AND
POINTS NORTH UP TO THE I-78 CORRIDOR, AMOUNTS OF 8-12" ARE EXPECTED
WITH A PROLONGED PERIOD OF MIXING OCCURRING. SOUTH OF THAT LINE, 4-
8" ARE EXPECTED AND MOST LOCATIONS IN THIS ZONE LIKELY EVEN SEE SOME
PLAIN RAIN.
WITH A FRIGID COLD AIRMASS OVERHEAD AND A STRONG PUSH OF WARM AIR
ALOFT, THERE IS A GROWING THREAT FOR FREEZING RAIN AND ICE
ACCUMULATION. THE CORRIDOR OF HIGHEST AMOUNTS HAS SHIFTED SOUTHEAST
A BIT, WITH THE CURRENT FORECAST HAVING A STRIPE OF 0.25"-0.4" OVER
THE EASTERN SHORE, EXTENDING INTO CENTRAL DE, AND CONTINUING INTO
CUMBERLAND/SALEM/GLOUCESTER/AND PART OF CAMDEN COUNTY IN NJ. THE I-
95 CORRIDOR, ONCE THE FOCUS OF THE HIGHER AMOUNTS, HAS TRENDED DOWN
A BIT, THOUGH STILL SOMEWHAT SIGNIFICANT - AROUND A TENTH TO TWO
TENTHS OF AN INCH OF ICE. THE QUESTION IS GOING TO BE WHAT THE DEPTH
OF THE WARM NOSE IS. IF IT IS THINNER, EXPECT MORE SLEET. IF IT IS
DEEPER, THEN MORE FREEZING RAIN AND ICE IS LIKELY. THERE IS HIGHER
CONFIDENCE IN THE HIGHEST AMOUNTS LANDING SOMEWHERE BETWEEN THE I-95
CORRIDOR AND GARDEN STATE PARKWAY IN CENTRAL AND SOUTHERN NJ AND
THEN SOMEWHERE OVER CENTRAL AND NORTHERN DELMARVA. THESE ICE
ACCUMULATIONS COME AFTER ANYWHERE FROM 4-8/8-12" OF SNOW FALL. THIS
WILL ONLY HEIGHTEN THE IMPACTS, REGARDLESS OF EXACTLY HOW MUCH
FALLS.
OVERALL, NO CHANGES TO THE WINTER STORM WARNING, WHICH IS IN PLACE
TONIGHT THROUGH MONDAY MORNING. SNOW TAPERS OFF BY MIDDAY MONDAY,
TRANSITIONING TO A PROLONGED STRETCH OF VERY COLD TEMPERATURES.
KEY MESSAGE 3...ARCTIC AIR REMAINS IN PLACE THROUGH THE UPCOMING
WEEK WITH TEMPERATURES BELOW FREEZING INTO FRIDAY.
ARCTIC HIGH PRESSURE WILL THEN BE IN CONTROL FOR THE REST OF
NEXT WEEK, WITH MONDAY POSSIBLY BEING THE MILDEST DAY, THAT TERM
IS USED LOOSELY, WITH HIGHS IN THE UPPER 20S TO LOW 30S. A STRONG
COLD FRONT IS FORECAST TO CROSS THROUGH MONDAY NIGHT, AND THEN LOWS
WILL CRASH INTO THE SINGLE DIGITS. THE STRONG WINDS DEVELOPING
OVER THE AREA MONDAY NIGHT INTO TUESDAY MORNING WILL CREATE
WIDESPREAD WIND CHILLS WILL BE AS LOW AS 10 BELOW, WITH WIND CHILLS
AS LOW AS 20 BELOW IN THE SOUTHERN POCONOS. COLD WEATHER ADVISORIES
AND WARNINGS WILL LIKELY BE NEEDED. HIGHS WILL BE IN THE TEENS AND
LOW 20S TUESDAY, WITH HIGHS NOT MUCH WARMER THAN THAT THROUGH
FRIDAY. LOWS WILL BE IN THE SINGLE DIGITS.
AS A RESULT OF THIS PROLONGED COLD, DO NOT EXPECT THE NEW
SNOWPACK TO MELT MUCH.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS...
TODAY... VFR EXPECTED. INCREASING HIGH THEN MID CLOUDS THRU THE DAY.
NORTH WINDS 15 KTS WITH GUSTS 20 TO 25 KTS EARLY THEN
DECREASING TO AROUND 10 KTS LATE. HIGH CONFID.
TONIGHT... VFR THRU 06Z ALL SITES THEN VSBY/CIG RESTRICTIONS TOWARDS
DAWN AS SNOW OVERSPREAD ALL AREAS LATE. IFR/LIFR QUICKLY REALIZED AS
SNOW BEGINS. NORTHEAST TO EAST WINDS AROUND 5 KNOTS. MEDIUM/HIGH
CONFID.
OUTLOOK...
SUNDAY/SUNDAY NIGHT... WIDESPREAD LIFR CONDITIONS WITH SNOW, SLEET
AND FREEZING RAIN EXPECTED MUCH OF THE TIME. SNOW WILL PREDOMINATE
SUNDAY MORNING WITH ICE/SLEET MIXING IN FROM SOUTH/WEST TO
NORTH/EAST THRU THE AFTERNOON. PRECIP MAY CHANGE TO ALL RAIN KACY
DURING THE EVENING SUNDAY. EAST TO NORTHEAST WINDS 10 TO 15 KTS. LOW
CONFID WITH REGARDS TO P-TYPE/TIMING.
MONDAY... LOWER CONDITIONS EARLY THEN IMPROVEMENT BACK TO VFR BY
AFTERNOON.
TUE THRU WED... VFR MUCH OF THE TIME.
MARINE
A SMALL CRAFT ADVISORY AND FREEZING SPRAY ADVISORY ARE IN PLACE
THROUGH 1 PM TODAY. WIND GUSTS OUT OF THE NORTHWEST AROUND 25-30 KT
EXPECTED THROUGH DAYBREAK, DIMINISHING AS THE MORNING GOES ON WITH 4
TO 6 FOOT SEAS. WINDS HAVE BEEN A BIT SLOW TO WANE, SO THE SCA
ON DELAWARE BAY WAS EXTENDED UNTIL 9 AM, MATCHING THE EXPIRATION
TIME OF THE FREEZING SPRAY ADVISORY OVER THE BAY.
A PERIOD OF SUB-SCA CONDITIONS COMES FOR THE AFTERNOON AND
OVERNIGHT HOURS WITH NORTH/NORTHEAST WINDS AROUND 10-20 KT AND
SEAS 2 TO 4 FEET. SNOW MOVES OVER THE MARINE ZONES AS THE NIGHT
GOES ON, LIKELY REDUCING VISIBILITY.
OUTLOOK...
SUNDAY...A GALE WATCH IS IN EFFECT FOR ALL MARINE ZONES. WINDS OUT
OF THE EAST/NORTHEAST COULD GET NEAR 35 KT AT TIMES, ESPECIALLY OVER
THE OCEAN. SEAS OF 6 TO 9 FEET.
SUNDAY NIGHT THROUGH MONDAY NIGHT...SCA CONDITIONS EXPECTED WITH
GALES POSSIBLE (40-50%). SEAS 6 TO 9 FEET AND WINDS 20-30 KT,
OUT OF THE EAST/NORTHEAST ON SUNDAY NIGHT AND NORTHWEST ON
MONDAY.
TUESDAY...SCA CONDITIONS AND FREEZING SPRAY POSSIBLE.
WEDNESDAY...SUB-SCA CONDITIONS.
CLIMATE
AN IMPACTFUL WINTER STORM BRINGING SIGNIFICANT SNOW
ACCUMULATIONS TO THE AREA IS EXPECTED ON SUNDAY. HERE ARE THE
1-DAY DAILY RECORD TOTALS FOR JANUARY 25TH FROM OUR SNOW
OBSERVING SITES. SOME OF THESE COULD BE CHALLENGED.
JANUARY 25TH DAILY SNOWFALL RECORDS
ALLENTOWN (ABE) 10.4" (1988)
AC AIRPORT (ACY) 8.3" (2000)
PHILADELPHIA (PHL) 8.5" (2000)
READING (RDG) 9.0" (1905)
TRENTON (TTN) 14.0" (1905)
WILMINGTON (ILG) 10.0" (2000)
PHI WATCHES/WARNINGS/ADVISORIES
PA...COLD WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ060>062-070-071-101>106.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY
FOR PAZ060-070-071-101>106.
WINTER STORM WARNING FROM 1 AM SUNDAY TO 1 PM EST MONDAY FOR
PAZ054-055-061-062.
EXTREME COLD WARNING UNTIL 10 AM EST THIS MORNING FOR PAZ054-
055.
NJ...COLD WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR NJZ001-
007>010-012>027.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY
FOR NJZ008>010-012>021-026-027.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM EST MONDAY
FOR NJZ022>025.
WINTER STORM WARNING FROM 1 AM SUNDAY TO 1 PM EST MONDAY FOR
NJZ001-007.
DE...COLD WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
DEZ001>004.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY
FOR DEZ001-002.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM EST MONDAY
FOR DEZ003-004.
MD...COLD WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MDZ012-
015-019-020.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY
FOR MDZ012-015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR ANZ430-
431.
FREEZING SPRAY ADVISORY UNTIL 9 AM EST THIS MORNING FOR ANZ430-
431.
GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR
ANZ430-431.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
FREEZING SPRAY ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
ANZ450-451.
GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR
ANZ452>455.
DISCUSSION...HOEFLICH/OHARA
AVIATION...OHARA
MARINE...HOEFLICH
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