164
FXUS61 KPHI 160826
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
326 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
TONIGHT 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 EXTENDED THROUGH 6 AM FOR THESE
AREAS, AND CONTINUES THROUGH 10 AM FOR THE SOUTHERN POCONOS.
ADDITIONAL ICE AMOUNTS NEAR 0.1-0.2" 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 OHIO VALLEY WILL LIFT NORTHEAST ACROSS UPSTATE NEW
YORK, THEN EASTWARD AND MOVE OFFSHORE OF COASTAL NEW ENGLAND THIS
EVENING. AS IT PROGRESSES NORTHEASTWARD IT WILL DEEPEN AND
INTENSIFY. 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. 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 A BREAK IN PRECIPITATION 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. 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 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 /09Z 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 6 AM EST EARLY THIS MORNING FOR
PAZ060>062-105.
HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 PM EST MONDAY
FOR PAZ054-055-060>062-101>106.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ054-055.
NJ...HIGH WIND WARNING FROM 10 AM THIS MORNING TO 6 PM EST MONDAY
FOR NJZ013-014-016>027.
WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NJZ001-007>009.
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.
SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
ANZ450>455.
SYNOPSIS...JOHNSON/MPS
NEAR TERM...STAARMANN
SHORT TERM...JOHNSON
LONG TERM...JOHNSON/MPS
AVIATION...JOHNSON/MPS
MARINE...JOHNSON/STAARMANN
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