528
FXUS61 KPHI 161138
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
638 AM EST SUN FEB 16 2025
SYNOPSIS
THE LOW PRESSURE WILL MOVE NORTHEASTWARD THROUGH THE REGION
TODAY. A COLD FRONT ASSOCIATED WITH THIS LOW WILL MOVE THROUGH
OUR AREA LATE THIS AFTERNOON INTO EARLY THIS EVENING. HIGH
PRESSURE WILL SLOWLY BUILD TOWARDS OUR REGION THROUGH THE FIRST
HALF OF THE WEEK. A COASTAL STORM MAY IMPACT THE REGION
WEDNESDAY NIGHT THROUGH THURSDAY. HIGH PRESSURE RETURNS
THEREAFTER.
NEAR TERM /THROUGH MONDAY/
SUMMARY: STRONG STORM SYSTEM WILL CONTINUE TO IMPACT THE REGION
TODAY INTO MONDAY. WIDESPREAD PRECIPITATION WILL CONTINUE
THROUGH THIS AFTERNOON AS A WARM FRONT LIFTS NORTH THIS MORNING
AND A STRONG COLD FRONT ARRIVES BETWEEN 3 PM AND 6 PM. FREEZING
RAIN IN THE HIGHER ELEVATIONS NEAR AND NORTH OF I-78 THROUGH
EARLY THIS MORNING. THE WINTER WEATHER ADVISORY WAS EXPIRED FOR
MOST ZONES, BUT REMAINS IN EFFECT FOR THE SOUTHERN POCONOS AND
SUSSEX COUNTY NJ THROUGH 10 AM. ADDITIONAL ICE AMOUNTS NEAR
0.1" POSSIBLE IN THE ADVISORY AREA.
THROUGH THIS AFTERNOON, PERIODS OF MODERATE TO HEAVY SHOWERS
EXPECTED ALONG WITH POTENTIAL FOR THUNDER AND INCREASING WINDS.
POTENTIALLY SIGNIFICANT IMPACTS POSSIBLE FROM A HIGH WIND EVENT
EXPECTED TO IMPACT THE REGION BEGINNING THIS AFTERNOON THROUGH
MONDAY. A HIGH WIND WARNING REMAINS IN EFFECT FOR THE ENTIRE
AREA BEGINNING LATER TODAY THROUGH MONDAY.
A FEW SNOW SHOWERS OR SNOW SQUALLS POSSIBLE (10-20% CHANCE)
OVERNIGHT TONIGHT.
*SYNOPTIC AND MESOSCALE DISCUSSION:
A MID AND UPPER LEVEL TROUGH CURRENTLY EXTENDING ACROSS THE
MIDWEST INTO THE SOUTHEAST WILL TRANSLATE EASTWARD, MOVING
OFFSHORE OF THE EAST COAST TONIGHT, WITH PHASING POLAR AND SUB
TROPICAL JETS AS THE SYSTEM EVOLVES. AT THE SURFACE, A RAPIDLY
DEEPENING LOW CURRENTLY CENTERED IN THE UPPER OHIO VALLEY WILL
LIFT NORTHEAST ACROSS UPSTATE NEW YORK, THEN EASTWARD AND MOVE
OFFSHORE OF COASTAL NEW ENGLAND THIS EVENING WHILE STRENGTHENING
RAPIDLY AT A RATE OF OVER 1 MB/HOUR. THE LOW IS ANTICIPATED TO
DROP WELL BELOW 980 MB INTO TONIGHT. A WARM FRONT ASSOCIATED
WITH THIS LOW WILL LIFT NORTH INTO THE AREA EARLY TODAY, THEN
THE ASSOCIATED STRONG COLD FRONT WILL PASS THROUGH BETWEEN ABOUT
3 PM AND 6 PM LATE THIS AFTERNOON AND EARLY EVENING. AS THE
SYSTEM DEPARTS TONIGHT INTO MONDAY, STRONG ARCTIC HIGH PRESSURE
WILL BUILD ACROSS THE UPPER MIDWEST, WITH SURFACE RIDGING
EXTENDING EASTWARD INTO THE MID ATLANTIC BY MONDAY. OUR REGION
WILL THUS BE SANDWICHED BETWEEN TWO STRONG PRESSURE SYSTEMS,
CREATING A STRONG PRESSURE GRADIENT WITH HIGH WINDS IN PLACE
ACROSS THE AREA TONIGHT INTO MONDAY.
*RAIN AND CONVECTION FORECAST DETAILS:
THE STRONG ISENTROPIC ASCENT IN PLACE ACROSS THE AREA EARLY
THIS MORNING WILL GRADUALLY LIFT NORTH LATER THIS MORNING. THIS
SHOULD YIELD SOME BREAKS IN RAINFALL AT TIMES FOR MANY AREAS BY
MID TO LATE MORNING, ALTHOUGH AREAS OF DRIZZLE MAY PERSIST
NORTH OF THE WARM FRONT LIFTING NORTH INTO THE AREA. IN THE
MEANTIME, PERIODS OF RAIN SHOWERS WILL SPREAD ACROSS THE AREA.
GUIDANCE INDICATES SOME ELEVATED INSTABILITY, WHICH COULD RESULT
IN SOME RUMBLES OF THUNDER. THE WARM FRONT SHOULD BE NEAR I-95
AND THE PHILLY METRO BY AROUND NOON.
AS THE COLD FRONT APPROACHES INTO THE AFTERNOON, GUIDANCE HAS
COME TO A CONSENSUS THAT A BAND OF MODERATE TO HEAVY RAIN WILL
PUSH INTO THE AREA FROM WEST TO EAST. THIS BAND COULD CONTAIN A
NARROW CONVECTIVE LINE, WHICH COULD HELP TO BEGIN MIXING DOWN
THE STRONGER WINDS ALOFT IN THE WARM SECTOR. ADDITIONAL
INSTABILITY SHOWERS COULD FORM BEHIND THE STRATIFORM BAND OF
RAIN ALONG THE ACTUAL COLD FRONT AS WELL. ANY CONVECTION COULD
HAVE THUNDER WITH IT.
*WIND AND TEMPERATURE FORECAST DETAILS:
IN THE WAKE OF THE STRONG COLD FRONT PASSING THROUGH AROUND 3
PM TO 6 PM, TEMPERATURES WILL PLUMMET FROM THE 50S TO NEAR 60
DEGREES INTO THE 30S THEN 20S WITH WIND CHILLS IN THE TEENS BY
LATE TONIGHT. THE MAIN CONCERN FOR LATE THIS AFTERNOON AND
EVENING THROUGH MONDAY WILL BE THE STRONG TO DAMAGING WEST TO
NORTHWEST WINDS DEVELOPING.
THE SYNOPTIC PATTERN IS VERY FAVORABLE FOR HIGH WINDS. SURFACE
PRESSURE RISES EXCEEDING 1 MB/HOUR, PERHAPS AS MUCH AS 8 MB
WITHIN JUST 3 HOURS, AND VERY STRONG COLD ADVECTION WILL SUPPORT
EFFICIENT BOUNDARY LAYER MIXING IMMEDIATELY IN THE WAKE OF THE
FRONTAL PASSAGE AND OVERNIGHT INTO MONDAY. A CONSENSUS OF
DETERMINISTIC BUFKIT PROFILES AND HREF ENSEMBLE PROFILES
INDICATE BOUNDARY LAYER MIXING THROUGH THE 925 MB LAYER, AND
PERHAPS AS HIGH AS THE 850 MB LAYER AT TIMES. WIND SPEEDS AT
THESE LEVELS AROUND 35-50 KTS SHOULD SERVE AS A GOOD PROXY FOR
WIND GUSTS GIVEN THE EFFICIENT MIXING. 925 MB WINDS LIKELY
SERVING AS A MORE PREVAILING WIND GUST PROXY, WITH 850 MB WINDS
SERVING AS A PEAK GUST PROXY. THIS WILL TRANSLATE TO FREQUENT
WESTERLY GUSTS IN THE 45-60 MPH RANGE ACROSS THE ENTIRE AREA,
WITH THE STRONGEST WINDS MOST LIKELY OCCURRING ACROSS THE HIGHER
ELEVATIONS AND NEAR THE COASTS.
STRONG WINDS WITH GUSTS 40-50 MPH COULD DEVELOP ACROSS THE
COASTAL PLAIN AHEAD OF THE FRONTAL PASSAGE LATE THIS MORNING AND
EARLY AFTERNOON. GUSTS DURING THIS TIMEFRAME WOULD BE AROUND
40-50 MPH AT MOST FROM THE SOUTH OR SOUTHWEST. THE PEAK GUSTS OF
THE EVENT NEAR 50-60 MPH ARE LIKELY TO OCCUR IMMEDIATELY IN THE
WAKE OF THE FRONTAL PASSAGE. THIS WILL BE WHEN THE
AFOREMENTIONED BOUNDARY LAYER WIND SPEEDS ARE STRONGEST AND
SURFACE PRESSURE RISES ARE SHARPEST. THEREAFTER, WESTERLY GUSTS
OF 40-55 MPH WILL LIKELY PREVAIL FOR MUCH OF TONIGHT THROUGH AT
LEAST THE FIRST HALF OF MONDAY BEFORE BEGINNING TO SUBSIDE. THE
HIGH WIND WARNING REMAINS IN EFFECT FOR AN EXTENDED PERIOD OF
IMPACTS FROM HIGH WINDS.
WHILE THE PEAK GUSTS UPWARDS OF 60 MPH ARE NOT EXPECTED TO
PREVAIL DURING THE ENTIRE WARNING PERIOD, WET SOILS COMBINED
WITH THE HIGH WINDS COULD RESULT IN EXTENSIVE TREE DAMAGE
THROUGH THE EVENT. ADDITIONALLY, THE STRONG WINDS WILL USHER IN
MUCH COLDER AIR, WITH TEMPERATURES IN THE 20S AND 30S AND WIND
CHILLS IN THE TEENS. WE ARE MOST CONCERNED ABOUT THE POTENTIAL
FOR POWER OUTAGES COMBINED WITH THE COLD, WHICH COULD EXACERBATE
THE IMPACTS OF THIS HIGH WIND EVENT FOR FOLKS THAT LOSE POWER
WITH IT BEING SO COLD OUT. PLEASE TAKE THIS EVENT SERIOUSLY!
AS PREVIOUSLY MENTIONED, LOW TEMPERATURES SUNDAY NIGHT INTO
MONDAY MORNING WILL BE MAINLY IN THE 20S TO NEAR 30 DEGREES WITH
WIND CHILLS DROPPING INTO THE TEENS. TEMPERATURES WILL STRUGGLE
TO CLIMB FROM MORNING MINIMUMS ON MONDAY, WITH HIGHS MAINLY IN
THE 30S AND MAXIMUM WIND CHILLS IN THE TEENS AND 20S.
SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/
THE MAIN CONCERN IN THE SHORT TERM IS DANGEROUSLY COLD
CONDITIONS BOTH MONDAY NIGHT AND TUESDAY NIGHT.
HIGH PRESSURE WILL SLOWLY BUILD CLOSER TO THE REGION FROM THE
WEST. WITH THE DEPARTING LOW, THERE WILL STILL BE A TIGHT
PRESSURE GRADIENT INTO TUESDAY MORNING, SO EXPECT BREEZY
CONDITIONS THROUGH THAT PERIOD. BECAUSE WINDS WILL STAY UP A
BIT, RADIATIVE COOLING WILL BE LIMITED. HOWEVER, WITH STRONG
COLD AIR ADVECTION BEHIND TODAY'S COLD FRONT, WIND CHILLS BOTH
MONDAY NIGHT AND TUESDAY NIGHT COULD GET CLOSE TO COLD WEATHER
ADVISORY CONDITIONS. MINIMUM WIND CHILLS BOTH NIGHTS ARE
EXPECTED TO BE IN THE SINGLE DIGITS ABOVE ZERO GENERALLY FOR THE
COASTAL PLAIN, AND BELOW ZERO FOR AREAS NORTH AND WEST OF THE
FALL LINE. IN THE HIGHER TERRAIN OF THE POCONOS AND NW NJ, WIND
CHILLS COULD BE LESS THAN -10 F. THIS COULD BE ESPECIALLY
IMPACTFUL IF THERE ARE ANY LINGERING POWER OUTAGES AFTER THE
STRONG WINDS EXPECTED IN THE NEAR TERM.
DRY CONDITIONS ARE LIKELY THROUGH THE PERIOD. SOME MODELS
DEPICT LAKE EFFECT SNOW SHOWERS WELL NORTHWEST OF OUR REGION,
BUT THE FETCH LOOKS UNFAVORABLE FOR THOSE TO MAKE IT AS FAR
SOUTHEAST AS OUR AREA.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
THE FOCUS IN THE LONG TERM IS ON THE COASTAL STORM LATE
WEDNESDAY THROUGH THURSDAY WHICH HAS THE POTENTIAL TO BRING
SNOW, ESPECIALLY TO THE COASTAL PLAINS. NO MAJOR CHANGES IN THE
FORECAST, THOUGH THERE REMAINS UNCERTAINTY, ESPECIALLY WITH THE
TIMING OF THE SYSTEM, AND THUS ULTIMATELY WITH THE IMPACTS OF
THE SYSTEM.
GUIDANCE HAS COME INTO PRETTY GOOD AGREEMENT OF THE TRACK OF
THE LOW. A LARGE CLUSTER OF GUIDANCE DEPICTS THE CENTER OF THE
SURFACE LOW PROGRESSING OFF THE COAST IN NORTHERN FL, THEN
STAYING CLOSE TO THE COAST UP THROUGH THE OUTER BANKS, BEFORE
TRACKING NORTHEASTWARD, FURTHER AWAY FROM THE COAST. THERE IS
NOT ONLY GOOD AGREEMENT BETWEEN MODELS, BUT THIS IS ALSO CLOSE
TO THE CONSENSUS TRACK FROM THE SATURDAY MORNING MODEL RUN.
HOWEVER, WHERE THERE REMAINS UNCERTAINTY IS SOME MODELS DEPICT
THIS AS A SLOW MOVING SYSTEM THAT IS THUS ABLE TO ADVECT
MOISTURE MUCH FURTHER INLAND AND THUS HAS A LARGER FOOTPRINT OF
PRECIP TO THE LEFT OF THE LOW, BRINGING SNOW TO OUR AREA FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING. OTHER GUIDANCE SHOWS A
FAST MOVING SYSTEM, AFFECTING OUR REGION FROM THE LATER HALF OF
THE DAY ON WEDNESDAY THROUGH THURSDAY MORNING.
THE PROBABILITIES FROM THE NATIONAL BLEND OF MODELS (NBM)
HAVEN'T CHANGED MUCH FROM THE PREVIOUS SHIFT: A 20 TO 40 PERCENT
PROBABILITY FOR MORE THAN 4 INCHES OF SNOW NORTH AND WEST OF
THE I-95 CORRIDOR AND A 40 TO 70 PERCENT PROBABILITY FOR MORE
THAN 4 INCHES OF SNOW ACROSS THE I-95 CORRIDOR AND COASTAL
PLAINS 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 30 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 FOR THE COASTAL PLAINS.
CANADIAN HIGH PRESSURE BUILDS BACK IN FROM THE WEST FOR FRIDAY
AND SATURDAY WITH A RETURN TO DRY CONDITIONS.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH TODAY...STARTING IFR OR LOWER DUE TO LOW CEILINGS AND
VISIBILITY RESTRICTIONS IN RAIN. ISOLATED 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. ASIDE FROM KACY, OTHER TAF
SITES HAVE WINDS NEAR OR BELOW 10 KT AND THAT SHOULD CONTINUE
THROUGH 12Z. AFTER 12Z, EXPECT SOUTHEASTERLY OR SOUTHERLY WINDS
TO INCREASE. WITH THE COLD FRONT, EXPECT AN ABRUPT SHIFT TO
STRONG WESTERLY WINDS WITH GUSTS APPROACHING 50 KT POSSIBLE. LOW
LEVEL WIND SHEAR DURING THE MORNING BEFORE BETTER MIXING
DISPERSES IT DURING THE MIDDAY HOURS.
TONIGHT...VFR. WESTERLY WINDS SHOULD DECREASE SLIGHTLY, BUT
GUSTS NEAR OR ABOVE 40 KT STILL POSSIBLE.
OUTLOOK...
MONDAY...VFR. WESTERLY WINDS GUSTING NEAR 40KT ESPECIALLY EARLY
IN THE DAY.
MONDAY NIGHT THROUGH WEDNESDAY...VFR.
WEDNESDAY NIGHT THROUGH THURSDAY...SUB-VFR LIKELY IN SN.
MARINE
GALE FORCE SOUTHERLY WINDS DEVELOPING LATER TODAY AHEAD OF A
STRONG COLD FRONT. PERIODS OF RAIN AND POSSIBLE THUNDER AND
AREAS OF FOG. SEAS BUILDING 8-12 FEET BY THIS AFTERNOON.
A STRONG COLD FRONT WILL PASS QUICKLY OFFSHORE AROUND 4 PM TO 6
PM. THE FRONT WILL BRING AND ABRUPT SHIFT IN WIND DIRECTION TO
WESTERLY. STORM FORCE GUSTS NEAR 50 KTS ARE ANTICIPATED FOR A
FEW HOURS FOLLOWING THE COLD FRONT, WHICH HAS PROMPTED THE
UPGRADE TO A STORM WARNING FOR THE PERIOD. FOLLOWING THE STORM
WARNING, A GALE WARNING WILL BE NEEDED THROUGH MONDAY. SEAS 5-9
FEET TONIGHT INTO MONDAY.
LOW WATER IS POSSIBLE NEAR THE TIMES OF LOW TIDE BEGINNING
TONIGHT THROUGH TUESDAY.
OUTLOOK...
MONDAY NIGHT AND TUESDAY...WINDS AND SEAS WILL GRADUALLY
SUBSIDE BELOW SCA CRITERIA THROUGH THE EARLY PART OF THE DAY
TUESDAY.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WINDS AND SEAS SHOULD
STAY BELOW SCA CRITERIA.
THURSDAY...SCA CONDITIONS ARE POSSIBLE, ESPECIALLY ON THE
ATLANTIC COASTAL WATERS.
PHI WATCHES/WARNINGS/ADVISORIES
PA...HIGH WIND WARNING FROM 10 AM THIS MORNING TO 6 PM EST MONDAY
FOR PAZ070-071.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ054-055.
HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 PM EST MONDAY
FOR PAZ054-055-060>062-101>106.
NJ...HIGH WIND WARNING FROM 10 AM THIS MORNING TO 6 PM EST MONDAY
FOR NJZ013-014-016>027.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NJZ001.
HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 PM EST MONDAY
FOR NJZ001-007>010-012-015.
DE...HIGH WIND WARNING FROM 10 AM THIS MORNING TO 6 PM EST MONDAY
FOR DEZ001>004.
MD...HIGH WIND WARNING FROM 10 AM THIS MORNING TO 6 PM EST MONDAY
FOR MDZ012-015-019-020.
MARINE...STORM WARNING UNTIL 6 AM EST MONDAY FOR ANZ430-431-450>455.
LOW WATER ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EST MONDAY
FOR ANZ450.
SYNOPSIS...JOHNSON/MPS
NEAR TERM...STAARMANN
SHORT TERM...JOHNSON
LONG TERM...JOHNSON/MPS
AVIATION...JOHNSON/MPS
MARINE...JOHNSON/STAARMANN
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