181
FXUS61 KPHI 160250
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
950 PM EST SAT FEB 15 2025
SYNOPSIS
LOW PRESSURE WORKS ITS WAY THROUGH THE REGION LATE TONIGHT
THROUGH SUNDAY, AND THEN A COLD FRONT PASSES THROUGH THE REGION
SUNDAY NIGHT. HIGH PRESSURE BUILDS IN FROM THE WEST STARTING
SUNDAY NIGHT AND WILL DOMINATE THROUGH WEDNESDAY. A COASTAL
STORM MAY IMPACT THE REGION WEDNESDAY NIGHT THROUGH THURSDAY.
HIGH PRESSURE RETURNS THEREAFTER.
NEAR TERM /THROUGH SUNDAY/
950 PM UPDATE...EXTENDED SOUTHERN TIER OF WINTER WEATHER
ADVISORIES UNTIL MIDNIGHT AND NORTHERN SEGMENT UNTIL 6 AM AS
TEMPERATURES ARE HARDLY MOVING PRESENTLY. ADJUSTED ICE AMOUNTS
UPWARD A BIT, BUT STILL LOOKS LIKE MOSTLY ADVISORY LEVEL AND NOT
WARNING CRITERIA. NO OTHER CHANGES OF SIGNIFICANCE AT THIS
TIME.
730 PM UPDATE...NO BIG CHANGES, THOUGH SNOW HAS QUICKLY
TRANSITIONED TO FREEZING RAIN ACROSS THE REGION, RESULTING IN
LOWER THAN EXPECTED TOTALS, WITH MOST PLACES AT OR BELOW 2
INCHES. MAIN CONCERN OVERNIGHT WILL BE ICING WHERE TEMPERATURES
ARE BEING STUBBORN TO RISE, SO MAY HAVE TO TWEAK TIMING OF
WINTER WEATHER ADVISORIES TO END A BIT LATER THAN THEY CURRENTLY
DO. OTHERWISE, FORECAST ON TRACK OVERALL AND NO NOTABLE CHANGES
WERE MADE FOR TOMORROW OR BEYOND.
AFTERNOON DISCUSSION...
THERE WERE NO MAJOR CHANGES TO THE NEAR TERM FORECAST WITH THIS
AFTERNOON'S UPDATE. AS OF THIS AFTERNOON, A DEEPENING STORM
SYSTEM WAS BEGINNING TO AFFECT THE AREA AND WILL CONTINUE TO DO
SO FOR THE REST OF TODAY AND TOMORROW RIGHT INTO MONDAY BRINGING
A NUMBER OF HAZARDS.
SYNOPTIC AND MESOSCALE DISCUSSION: A MID AND UPPER LEVEL TROUGH
CURRENTLY CENTERED OVER THE CENTRAL CONUS WILL TRANSLATE
EASTWARD, MOVING OFFSHORE OF THE EAST COAST SUNDAY NIGHT, WITH
PHASING POLAR AND SUB TROPICAL JETS AS THE SYSTEM EVOLVES. AT
THE SURFACE, A LOW CURRENTLY CENTERED NEAR ARKANSAS WILL
PROGRESS INTO WESTERN PA/EASTERN OH BY SUNDAY MORNING AND
EVENTUALLY INTO NEW ENGLAND BY LATE SUNDAY. AS IT PROGRESSES
NORTHEASTWARD IT WILL DEEPEN AND INTENSIFY. THE LOW IS
ANTICIPATED TO DROP WELL BELOW 990 MB. A WARM FRONT ASSOCIATED
WITH THIS LOW WILL LIFT NORTH INTO THE AREA EARLY SUNDAY, THEN
THE ASSOCIATED STRONG COLD FRONT WILL FOLLOW SUNDAY AFTERNOON.
STRONG ISENTROPIC ASCENT IS RESULTING IN PRECIPITATION
SPREADING INTO THE REGION FAIRLY QUICKLY AT THIS TIME AHEAD OF
THE MAIN SURFACE LOW. STEADY PRECIPITATION IS EXPECTED FOR THE
REST OF THIS AFTERNOON THROUGH MOST OF TONIGHT. AS THE CENTER OF
THE LOW MAKES ITS CLOSEST APPROACH LATE TONIGHT INTO EARLY
SUNDAY MORNING, WE COULD SEE SOME BREAKS IN THE PRECIPITATION AS
OUR REGION IS IN A PRIME LOCATION FOR THE DRY SLOT (ALBEIT
BRIEFLY).
THE LAST ROUND OF PRECIPITATION (ALL RAIN BY THIS POINT) WILL
COME WITH AND JUST AHEAD OF THE COLD FRONT SUNDAY AFTERNOON.
IMPACTS DISCUSSION:
WINTRY WEATHER: THE MAIN CONCERN FOR WINTRY WEATHER IMPACTS IS
FOR AREAS NEAR AND NORTH OF THE INTERSTATE 78 CORRIDOR. IN THESE
AREAS, ALTHOUGH SNOW ACCUMULATIONS ARE EXPECTED TO BE BARELY
ADVISORY LEVEL (OR IN SOME CASES BELOW THE GUIDANCE FOR
ADVISORIES), THE MAIN IMPACTS ARE GOING TO BE COMING WITH THE
PERIOD OF SLEET AND FREEZING RAIN IN BETWEEN THE SNOW AND THE
CHANGE OVER TO ALL RAIN. FOR MOST OF THE ADVISORY AREA, SNOW
AMOUNTS OF 1 TO 3 INCHES WITH ADDITIONAL ICE AMOUNTS OF A FEW
HUNDREDTHS OF AN INCH ARE POSSIBLE. THE EXCEPTION IS THE
SOUTHERN POCONOS AND FAR NW NEW JERSEY WHERE IN HIGHER
ELEVATIONS, TEMPERATURES COULD STAY BELOW FREEZING THROUGH EARLY
SUNDAY MORNING. CONSEQUENTLY, ICE AMOUNTS OF UP TO THREE TENTHS
OF AN INCH ARE POSSIBLE IN THE HIGHER TERRAIN OF THESE AREAS.
THE COMBINATION OF THE SNOW AND ICE WILL CREATE SLIPPERY
CONDITIONS. IN AREAS THAT GET MORE ICE ACCUMULATION, SOME MINOR
TREE AND WIRE IS POSSIBLE. THE GOOD NEWS IS THAT CONDITIONS WILL
IMPROVE QUICKLY ONCE THE TEMPERATURE GETS ABOVE FREEZING, AS
WITH RAIN CONTINUING TO FALL, ANY ICE AND SNOW SHOULD MELT
QUICKLY.
FARTHER SOUTH AND EAST, INCLUDING THE INTERSTATE 95 CORRIDOR,
PRECIPITATION IS STARTING AS SOME SNOW THIS AFTERNOON AND SOME
MINOR ACCUMULATION IS POSSIBLE BEFORE A CHANGE TO RAIN OCCURS BY
EARLY THIS EVENING. FOR PORTIONS OF THE COASTAL PLAINS, THERE
MAY ONLY BE A BRIEF PERIOD OF A RAIN AND SNOW MIX BEFORE THE
CHANGE OVER TO ALL RAIN. DUE TO THE LIMITED DURATION OF WINTRY
PRECIPITATION IN THESE LATTER AREAS (I-95 CORRIDOR AND POINTS
SOUTH), WINTRY IMPACTS SHOULD BE VERY LIMITED.
HEAVY RAIN/FLOODING THREAT: A WIDESPREAD 1 TO 2 INCHES OF TOTAL
LIQUID EQUIVALENT PRECIPITATION (FROM TODAY THROUGH THE END OF
THE DAY ON SUNDAY) IS STILL EXPECTED. OVERALL, WE'RE NOT
EXPECTING A WIDESPREAD FLOODING THREAT AS RIVER AND STREAM
LEVELS MOSTLY REMAIN RELATIVELY LOW. ADDITIONALLY, THE SNOW PACK
FROM THE STORM EARLIER THIS WEEK HAS MELTED AND HAD A CHANCE TO
ABSORB/RUNOFF ALREADY. ADDITIONALLY, THE POTENTIAL FOR A BREAK
IN THE PRECIP, OR AT LEAST LIGHTER PRECIP, ON SUNDAY MORNING
WITH THE DRY SLOT WOULD FURTHER HELP LIMIT THE FLOODING THREAT.
THAT BEING SAID, THIS COULD STILL BE ENOUGH TO CAUSE SOME
LOCALIZED FLOODING ESPECIALLY FOR POOR DRAINAGE AREAS. FOR THE
AREA WATERWAYS, THE FOCUS IS ON THE MILLSTONE RIVER WHICH TENDS
TO BE ONE OF THE FASTEST RESPONDING WATERWAYS IN OUR REGION, AND
IS CURRENTLY FORECAST TO GET CLOSE TO FLOOD STAGE BY LATE
SUNDAY EVENING.
THUNDERSTORMS: ISOLATED THUNDERSTORMS WILL BE POSSIBLE SUNDAY
MORNING, AND WITH THE FINAL ROUND OF SHOWERS THAT COMES IN WITH
THE COLD FRONT AROUND THE EARLY TO MID AFTERNOON TIMEFRAME.
INSTABILITY IS LIMITED, BUT THERE WILL BE AMPLE SHEAR IN PLACE.
THERE IS A MARGINAL RISK FOR SEVERE STORMS WITH STRONG WINDS.
THAT BEING SAID, WINDS WILL BE A THREAT EVEN OUTSIDE OF
THUNDERSTORMS, SO WILL MESSAGE THIS WITHIN THE BROADER HIGH WIND
WATCH (SEE MORE INFORMATION ON THE HIGH WIND WATCH IN THE SHORT
TERM SECTION BELOW).
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
PRECIPITATION ENDS BY SUNDAY EVENING, AND THEN ARCTIC HIGH
PRESSURE BUILDS IN FROM THE WEST AS LOW PRESSURE INTENSIFIES
OVER MAINE AND EASTERN CANADA. THIS RESULTS IN A TIGHT PRESSURE
GRADIENT OVER THE AREA SUNDAY NIGHT THROUGH MONDAY WITH THE
POTENTIAL FOR SIGNIFICANT HIGH WIND IMPACTS OVER THE AREA.
AT 925 MB, WINDS WILL BE ON THE ORDER OF 40 TO 45 KT, AND AT
850 MB, WINDS WILL BE ON THE ORDER OF 45 TO 55 KT SUNDAY THROUGH
MONDAY AFTERNOON. BUFKIT SOUNDING INDICATING A WELL MIXED
ATMOSPHERE UP TO 850 MB, AND THIS SHOULD TRANSLATE TO WEST WINDS
AVERAGING 25 TO 35 MPH WITH GUSTS 45 TO 55 MPH, AND PEAK GUSTS
AS HIGH AS 60 MPH. THERE SHOULD BE ONE SURGE SUNDAY EVENING,
THEN ANOTHER MONDAY MORNING AFTER SUNRISE. WILL GO AHEAD AND
CONVERT THE HIGH WIND WATCH TO A HIGH WIND WARNING. WINDS BEGIN
TO DIMINISH MONDAY AFTERNOON, THEN SETTLE DOWN NIGHT AS THE
PRESSURE GRADIENT RELAXES. LOCALIZED POWER OUTAGES MAY OCCUR.
DRY WEATHER ON TAP FOR THE SHORT TERM PERIOD AS HIGH PRESSURE
CONTINUES TO BUILD EAST. TEMPERATURES WILL RUN SOME 10 TO 15
DEGREES BELOW THE SEASONAL AVERAGE FOR THIS TIME OF YEAR WITH
HIGHS GENERALLY IN THE LOW TO MID 30S MONDAY AND EVEN COLDER,
TOPPING OFF IN THE 20S TO LOW 30S ON TUESDAY. WIND CHILL VALUES
MONDAY NIGHT/TUESDAY MORNING WILL GENERALLY BE IN THE SINGLE
DIGITS FOR MOST OF THE AREA, THOUGH POSSIBLY AS LOW AS -15 IN
THE SOUTHERN POCONOS.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
COLD HIGH PRESSURE DOMINATES THE LONG TERM PERIOD WITH
TEMPERATURES RUNNING SOME 10 TO 15 DEGREES BELOW NORMAL FOR THIS
TIME OF YEAR. HIGHS WILL BE IN THE 20S AND LOW 30S WEDNESDAY
THROUGH THURSDAY, AND THEN HIGHS CREEP UP A BIT INTO THE LOW TO
MID 30S FRIDAY AND SATURDAY. LOWS WILL MOSTLY BE IN THE TEENS
AND LOW 20S. SINCE IT WILL BE FAIRLY BREEZY, WIND CHILL VALUES
WILL MOSTLY BE IN THE TEENS TO LOW 20S AT NIGHT.
THE MAIN STORY WILL BE A POTENTIAL SNOWSTORM THAT COULD IMPACT
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY. THIS IS STILL IN THE
DAY 5- DAY 6 TIMEFRAME, AND THERE IS STILL A GOOD DEAL OF
UNCERTAINTY AMONG THE MODELS. 12Z/15 MODEL RUNS SEEM TO HAVE
MORE OF A SOUTHEAST TRACK WITH THE LOW, MEANING HIGHEST SNOW
ACCUMULATIONS WOULD BE OVER DELMARVA AND SOUTHEAST NEW JERSEY,
AND BACK TOWARDS THE I-95 CORRIDOR. WILL CONTINUE TO FOLLOW NBM
GUIDANCE AND WILL CARRY CATEGORICAL POPS FOR SOUTHERN DELMARVA
WEDNESDAY NIGHT AND LIKELY POPS FOR ALL BUT THE LEHIGH VALLEY
AND SOUTHERN POCONOS WEDNESDAY NIGHT AND THURSDAY.
FOR REFERENCE, THE 13Z/15 NBM SHOWING A 30 TO 50 PERCENT
PROBABILITY FOR MORE THAN 4 INCHES OF SNOW NORTH AND WEST OF THE
I-95 CORRIDOR AND A 50 TO 70 PERCENT PROBABILITY FOR MORE THAN
4 INCHES OF SNOW ACROSS SOUTHERN NEW JERSEY, THE EASTERN SHORES
OF MARYLAND AND DELAWARE IN THE 48 HOUR PERIOD FROM 7 AM
WEDNESDAY THROUGH 7 AM FRIDAY; A 20 TO 30 PERCENT PROBABILITY
FOR MORE THAN 8 INCHES OF SNOW NORTH AND WEST OF THE I-95
CORRIDOR AND A 40 TO 50 PERCENT PROBABILITY FOR MORE THAN 8
INCHES OF SNOW ACROSS SOUTHERN NEW JERSEY, THE EASTERN SHORES OF
MARYLAND AND DELAWARE IN THE 48 HOUR PERIOD FROM 7 AM WEDNESDAY
THROUGH 7 AM FRIDAY; AND A 20 TO 30 PERCENT PROBABILITY FOR
MORE THAN 12 INCHES OF SNOW ACROSS THE REGION IN THE 48 HOUR
PERIOD FROM 7 AM WEDNESDAY THROUGH 7 AM FRIDAY.
CANADIAN HIGH PRESSURE BUILDS BACK IN FROM THE WEST FOR FRIDAY
AND SATURDAY WITH A RETURN TO DRY CONDITIONS.
AVIATION /03Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...IFR OR LOWER CONDITIONS AND RA ARE LIKELY TO CONTINUE
THROUGH THE OVERNIGHT PERIOD AT ALL SITES, EXCEPT FZRA LASTING
FOR A WHILE AT KABE. WINDS COULD BE LIGHT AND VARIABLE BUT
SHOULD GENERALLY FAVOR AN EASTERLY DIRECTION.
SUNDAY...IFR OR LOWER CONTINUING. SOME SHOWERS ALONG WITH LOW
CLOUDS, MIST, AND FOG DURING THE MORNING WITH SOME HEAVIER
SHOWERS AND POSSIBLE THUNDERSTORMS MOVING THROUGH AROUND THE
EARLY AFTERNOON TIME FRAME ALONG AND AHEAD OF A STRONG COLD
FRONT. BEHIND THE COLD FRONT LATE IN THE DAY, EXPECT IMPROVEMENT
TO VFR CONDITIONS. WINDS AROUND 10 KTS FOR THE FIRST PART OF
THE DAY, SHIFTING FROM SOUTHEASTERLY TO SOUTHWESTERLY. WITH THE
COLD FRONT, EXPECT AN ABRUPT SHIFT TO STRONG NORTHWESTERLY WINDS
WITH GUSTS APPROACHING 50 KT POSSIBLE. LOW LEVEL WIND SHEAR
DURING THE MORNING BEFORE BETTER MIXING DISPERSES IT DURING THE
MIDDAY HOURS.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY...VFR. W WINDS 25 TO 35 KT WITH 45
TO 55 KT GUSTS, DIMINISHING MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...VFR. NO SIGNIFICANT WEATHER.
WEDNESDAY NIGHT THROUGH THURSDAY...SUB-VFR LIKELY IN SN.
MARINE
WINDS AND SEAS RAMP UP THROUGH TONIGHT. WINDS WILL BE SOUTHEAST
AND SOUTHERLY AND THOUGH THIS IS TYPICALLY AN UNFAVORABLE FLOW
REGIME FOR GALE FORCE GUSTS, A VERY STRONG LOW LEVEL JET IS
EXPECTED TO BE JUST ABOVE THE SURFACE ON SUNDAY, SO WINDS 35 TO
40 KT WILL BE POSSIBLE DURING THE MORNING ON SUNDAY. AN ABRUPT
WIND SHIFT (TO WESTERLY WINDS) AND QUICK INCREASE IN WINDS IS
EXPECTED WITH A COLD FRONT WHICH SHOULD MOVE OVER THE WATERS
LATE IN THE DAY. BY EVENING, EXPECT WEST WINDS GUSTING TO 45+
KNOTS. THUS, HAVE UPGRADED GALE TO STORM WARNING.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY...STORM WARNING IN EFFECT. W TO NW
WINDS 25 TO 35 KT WITH GUSTS 45+ KT. SEAS AS HIGH AS 10 TO 15
FT SUNDAY NIGHT, DIMINISHING TO 6 TO 9 FT ON MONDAY. LOW WATER
LEVELS COULD MAKE NAVIGATION DIFFICULT AROUND THE TIMES OF LOW
TIDE.
MONDAY NIGHT THROUGH TUESDAY...LINGERING GALES MONDAY EVENING
POSSIBLE, OTHERWISE, SCA CONDITIONS WITH W WINDS GUSTING 25 TO
30 KT AND OCEAN SEAS 4 TO 6 FT.
WEDNESDAY...SUB-SCA CONDITIONS.
WEDNESDAY NIGHT THROUGH THURSDAY...SUB-SCA CONDITIONS WEDNESDAY
NIGHT, THEN SCA CONDITIONS THURSDAY. VSBY RESTRICTIONS IN SN
LIKELY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...HIGH WIND WARNING FROM 10 AM SUNDAY TO 6 PM EST MONDAY FOR
PAZ070-071.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR PAZ061-062.
HIGH WIND WARNING FROM 1 PM SUNDAY TO 6 PM EST MONDAY FOR
PAZ054-055-060>062-101>106.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ060-
103-105.
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR PAZ054-055.
NJ...HIGH WIND WARNING FROM 10 AM SUNDAY TO 6 PM EST MONDAY FOR
NJZ013-014-016>027.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NJZ001-007-
008.
HIGH WIND WARNING FROM 1 PM SUNDAY TO 6 PM EST MONDAY FOR
NJZ001-007>010-012-015.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ009-
010.
DE...HIGH WIND WARNING FROM 10 AM SUNDAY TO 6 PM EST MONDAY FOR
DEZ001>004.
MD...HIGH WIND WARNING FROM 10 AM SUNDAY TO 6 PM EST MONDAY FOR
MDZ012-015-019-020.
MARINE...STORM WARNING FROM 6 AM SUNDAY TO 10 PM EST MONDAY FOR ANZ430-
431-450>455.
SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ450>455.
SYNOPSIS...MPS
NEAR TERM...FITZSIMMONS/RCM
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...FITZSIMMONS/MPS/RCM
MARINE...FITZSIMMONS/MPS/RCM
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