093
FXUS61 KPHI 212328
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
628 PM EST WED JAN 21 2026
WHAT HAS CHANGED
LOW PRESSURE CONTINUES TO BE ON TRACK TO IMPACT THE AREA WITH THE
POTENTIAL FOR SIGNIFICANT SNOW IMPACTS. WHILE THERE ARE SOME TRENDS
THAT SHOW A SLIGHTLY MORE NORTHERN TRACK WHICH COULD RESULT IN SLEET
AND FREEZING RAIN THAT WOULD RESULT IN SLIGHTLY LOWER SNOWFALL
TOTALS, IMPACTS WILL STILL BE SIGNIFICANT. CONFIDENCE REMAINS
LOW ON EXACT SNOW TOTALS AND WHERE THE HIGHEST SNOW TOTALS WILL
FALL.
KEY MESSAGES
1. A WARM-UP IS EXPECTED THROUGH THURSDAY AHEAD OF AN ARCTIC COLD
FRONT THAT CROSSES THROUGH THE AREA LATE IN THE DAY.
2. AN ARCTIC AIRMASS SPREADS INTO THE REGION FRIDAY NIGHT.
BITTERLY COLD TEMPERATURES AND WIND CHILLS RETURN TO THE AREA
FRIDAY NIGHT THROUGH SATURDAY.
3. LOW PRESSURE WILL IMPACT THE AREA WITH THE POTENTIAL FOR
SIGNIFICANT SNOW IMPACTS, AS WELL AS A WINTRY MIX, SATURDAY
NIGHT THROUGH MONDAY MORNING.
DISCUSSION
KEY MESSAGE 1...A WARM-UP IS EXPECTED THROUGH THURSDAY AHEAD OF
AN ARCTIC COLD FRONT THAT CROSSES THROUGH THE AREA LATE IN THE
DAY.
HIGH PRESSURE HAS SHIFTED OFFSHORE. LOW PRESSURE TRACKING
THROUGH THE NORTHERN GREAT LAKES WILL CONTINUE TO SLIDE EAST,
LIFTING A WARM FRONT THROUGH THE AREA EARLY THIS EVENING.
DESPITE VERY DRY LOW LEVELS, AND THE BETTER LIFT/MOISTURE
DISPLACED FURTHER WEST, A FEW FLURRIES AND/OR SNOW SHOWERS MAY
CLIP THE LEHIGH VALLEY, POCONOS AND NORTHERN NEW JERSEY AS THE
FRONT LIFTS THROUGH THIS EVENING. NO ACCUMULATIONS ARE EXPECTED.
A WARM AIR ADVECTION REGIME WILL BEGIN ONCE THE FRONT PASSES,
SO LOW TEMPERATURES TONIGHT WILL LIKELY OCCUR EARLY THIS
EVENING, BEFORE ULTIMATELY RISING A FEW DEGREES OVERNIGHT. TEMPS
TONIGHT WILL LARGELY RANGE IN THE UPPER 20S TO UPPER 30S.
THE WAA ADVECTION REGIME WILL CONTINUE ON THURSDAY AS SOUTHERLY
FLOW CONTINUES TO PUMP MILDER AIR NORTHWARD. AS A RESULT, HIGH
TEMPERATURES ARE EXPECTED TO RISE INTO THE LOW 40S TO LOW 50S
ACROSS THE AREA. HOWEVER, THE WARMTH WILL BE SHORT-LIVED AS YET
ANOTHER ARCTIC COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED LOW
PRESSURE CROSSES THROUGH THE AREA LATE IN THE AFTERNOON. AS OF
NOW, THE FRONT LACKS ANY MOISTURE THIS FAR SOUTH, SO OTHER THAN
AN INCREASE IN CLOUDS DURING THE DAY, NO PRECIPITATION IS
EXPECTED.
KEY MESSAGE 2...AN ARCTIC AIRMASS SPREADS INTO THE REGION
FRIDAY NIGHT. BITTERLY COLD TEMPERATURES AND WIND CHILLS RETURN
TO THE AREA FRIDAY NIGHT THROUGH SATURDAY.
A COLD FRONT MOVES THROUGH THE REGION FRIDAY NIGHT, AND THEN
STRONG COLD AIR ADVECTION WILL BE UNDERWAY LATE FRIDAY NIGHT
THROUGH SATURDAY. A TIGHT PRESSURE GRADIENT FORMS BETWEEN LOW
PRESSURE OVER THE CANADIAN MARITIMES AND HIGH PRESSURE BUILDING
INTO THE GREAT LAKES AND OHIO VALLEY. NORTHWEST WINDS WILL
INCREASE TO 15 TO 20 MPH WITH 25 TO 35 MPH GUSTS FRIDAY NIGHT,
DIMINISHING THROUGH THE DAY SATURDAY. LOW TEMPERATURES WILL BE
DOWN INTO THE SINGLE DIGITS FOR THE SOUTHERN POCONOS, NORTHERN
NEW JERSEY, AND LEHIGH VALLEY DOWN TO THE FALL LINE AND FROM 10
TO 15 DEGREES FOR SOUTHERN NEW JERSEY, THE DELAWARE VALLEY,
INCLUDING PHILADELPHIA, AND DELMARVA. MINIMUM WIND CHILLS VALUES
WILL RANGE FROM 0 TO 10 BELOW FOR THE MAJORITY OF THE AREA, AND
FROM 10 TO 20 BELOW FOR THE SOUTHERN POCONOS AND FAR NORTHWEST
NEW JERSEY, WHERE A COLD WEATHER ADVISORY MAY BE NEEDED.
KEY MESSAGE 3...LOW PRESSURE WILL IMPACT THE AREA WITH THE
POTENTIAL FOR SIGNIFICANT SNOW IMPACTS, AS WELL AS A WINTRY MIX,
SATURDAY NIGHT THROUGH MONDAY MORNING.
HIGH PRESSURE BUILDING INTO THE GREAT LAKES AND OHIO VALLEY ON
SATURDAY LIFTS INTO EASTERN CANADA ON SUNDAY. THE POSITIONING OF
THE HIGH WILL GREATLY IMPACT HOW THE STORM AFFECTS THE LOCAL
AREA.
A DEEP UPPER TROUGH WITH STRONG SHORTWAVE ENERGY EXITS OUT OF
THE WEST COAST AND ROCKY MOUNTAINS SATURDAY NIGHT, AND THEN
SURFACE LOW PRESSURE ORGANIZES AND DEVELOPS AHEAD OF IT OVER THE
TEXAS GULF COAST. THIS LOW THEN TRACKS THROUGH THE GULF COAST
STATES AND THE TENNESSEE VALLEY SUNDAY BEFORE MOVING OFF THE
MID-ATLANTIC COAST SUNDAY EVENING, THEN MOVING OUT TO SEA SUNDAY
NIGHT.
SNOW DEVELOPS SATURDAY EVENING FIRST OVER DELMARVA, THEN
LIFTING NORTH INTO THE SOUTHERN POCONOS AND FAR NORTHWEST NEW
JERSEY BY DAYBREAK SUNDAY. WHAT CONTINUES TO BE AN ISSUE IS THE
POSITION OF THE SURFACE LOW. THERE ARE SOME SIGNALS THAT THE
HIGH WILL BE A BIT FARTHER NORTH, ALLOWING THE LOW TO TAKE A
SLIGHTLY MORE NORTHERN TRACK. THIS ALLOWS FOR AT LEAST SOME
SLEET AND FREEZING RAIN FOR DELMARVA AND SOUTHERN NEW JERSEY,
AND POSSIBLY EVEN A PERIOD OF ALL RAIN FOR SOUTHERN DELAWARE AND
EXTREME SOUTHEAST NEW JERSEY. SNOW CONTINUES THROUGH SUNDAY
NIGHT BEFORE TAPERING OFF MONDAY MORNING.
13Z/21 NBM HAS A 90 TO 100 PERCENT PROBABILITY FOR MORE THAN 6
INCHES OF SNOW FOR MOST OF DELMARVA, THE DELAWARE VALLEY
INCLUDING PHILADELPHIA AND INTO SOUTHERN NEW JERSEY FOR THE 48
HOUR PERIOD ENDING AT 7 AM MONDAY AND AN 80 TO 90 PERCENT
PROBABILITY FOR MORE THAN 6 INCHES OF SNOW FOR THE SOUTHERN
POCONOS, LEHIGH VALLEY, AND NORTHERN NEW JERSEY. IN ADDITION,
13Z/21 NBM HAS A 70 TO 80 PERCENT PROBABILITY FOR MORE THAN 12
INCHES OF SNOW FOR MOST OF DELMARVA, THE DELAWARE VALLEY
INCLUDING PHILADELPHIA AND INTO SOUTHERN NEW JERSEY FOR THE 48
HOUR PERIOD ENDING AT 7 AM MONDAY AND A 60 TO 70 PERCENT
PROBABILITY FOR MORE THAN 12 INCHES OF SNOW FOR THE REST OF THE
FORECAST AREA.
IN ADDITION, THE 13Z/21 NBM HAS A 25 TO 35 PERCENT PROBABILITY
FOR MORE THAN 0.1 INCHES OF ICE FOR DELMARVA AND 10 TO 20
PERCENT PROBABILITY FOR MORE THAN 0.1 INCHES OF ICE FOR THE I-95
CORRIDOR IN SOUTHEAST PENNSYLVANIA AND NEW JERSEY, HIGHLIGHTING
THE POTENTIAL FOR THAT MIXING.
IN TERMS OF MODELS, THE 12Z/21 GFS HAS THE TRACK FARTHEST SOUTH
OF THE MODELS, AND RESULTS IN THE HIGHEST SNOWFALL, WHILE BOTH
THE CANADIAN AND THE ECMWF HAVE TRACKS FARTHER NORTH, WHICH
ALLOWS FOR MORE WARMER AIR ALOFT AND CUTS BACK ON SNOWFALL
TOTALS, ESPECIALLY FOR SOUTHERN NEW JERSEY AND DELMARVA.
WHILE CONFIDENCE REMAINS HIGH THAT WIDESPREAD IMPACTS WILL BE
SIGNIFICANT FROM THIS STORM, CONFIDENCE REMAINS LOW IN EXACT
SNOWFALL TOTALS AND WHERE THOSE HIGHEST TOTALS WILL OCCUR.
AVIATION /00Z THURSDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS...
TONIGHT...VFR WITH INCREASING CLOUD COVER. SOUTH-SOUTHWEST
WINDS AROUND 5-10 KT WITH OCCASIONAL GUSTS TO 20 KT. LOW-LEVEL
WIND SHEAR LIKELY UP TO 45 KT BETWEEN 00-12Z. SLIGHT CHANCE OF
A SNOW SHOWER AT KRDG/KABE/KTTN THROUGH 06Z. MODERATE- HIGH
CONFIDENCE.
THURSDAY...VFR. CLOUD COVER CLEARS OUT IN THE MORNING WITH
SCATTERED AFTERNOON CLOUDS. WEST-SOUTHWEST WINDS AROUND 10 KT
WITH OCCASIONAL GUSTS UP TO 20 KT POSSIBLE IN THE AFTERNOON.
MODERATE-HIGH CONFIDENCE.
OUTLOOK...
THURSDAY NIGHT THROUGH SATURDAY...VFR. NSW.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...SUB-VFR CONDITIONS IN SN,
WHICH MAY BE HEAVY AT TIMES. WINTRY MIX POSSIBLE ON SUNDAY FOR
AT LEAST KILG/KMIV/KACY.
MONDAY...LINGERING SN IN THE MORNING, THEN IMPROVING
CONDITIONS.
MARINE
SMALL CRAFT ADVISORIES FROM ON THE ATLANTIC COASTAL WATERS FROM
CAPE MAY TO CAPE HENLOPEN AND SANDY HOOK TO CAPE MAY ARE NOW IN
EFFECT UNTIL 10 AM THURSDAY AND 1 PM THURSDAY, RESPECTIVELY. A
SMALL CRAFT ADVISORY HAS BEEN ADDED FOR THE LOWER DELAWARE BAY
FROM 7 PM TONIGHT UNTIL 5 AM THURSDAY. NO HAZARDS ARE CURRENTLY
ISSUED FOR THE UPPER DELAWARE BAY.
SOUTH-SOUTHWEST WINDS INCREASE THIS AFTERNOON TO AROUND 15-20
KT WHERE GUSTS UP TO 25-30 KT ARE POSSIBLE THROUGH THIS EVENING.
WINDS AND GUSTS WILL THEN GRADUALLY DIMINISH THROUGH THE DAY ON
THURSDAY. SEAS OF 2-4 FEET THIS AFTERNOON, BUILD TO 4-7 FEET
TONIGHT, BEFORE GRADUALLY LOWERING TO 3-5 FEET ON THURSDAY. FAIR
WEATHER EXPECTED OUTSIDE OF SCA CONDITIONS.
OUTLOOK...
THURSDAY NIGHT THROUGH FRIDAY...SUB-SCA CONDITIONS.
FRIDAY NIGHT THROUGH SATURDAY...SCA CONDITIONS EXPECTED THROUGH
SATURDAY MORNING. FREEZING SPRAY POSSIBLE.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...SCA CONDITIONS EXPECTED
WITH GALE FORCE WINDS POSSIBLE. VSBY RESTRICTIONS IN SNOW AND
WINTRY MIX.
MONDAY...SCA CONDITIONS. VSBYS IMPROVE THROUGH THE DAY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR ANZ431.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR ANZ454-455.
DISCUSSION...DESILVA/MPS
AVIATION...DESILVA/GUZZO/MPS
MARINE...DESILVA/MPS
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