504
FXUS61 KPHI 280230
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
930 PM EST SUN NOV 27 2022
SYNOPSIS
LOW PRESSURE OVER THE ADIRONDACKS WILL CONTINUE TO MOVE
EASTWARD OVERNIGHT. A TRAILING COLD FRONT WILL CROSS EARLY
MONDAY. HIGH PRESSURE THEN BUILDS IN LATER MONDAY INTO TUESDAY
AHEAD OF ANOTHER LOW AND COLD FRONT THAT WILL RETURN RAIN
CHANCES FOR THE MIDDLE OF THE WEEK. CONDITIONS TURN DRIER AND
COOLER TO CLOSE OUT THE WEEK.
NEAR TERM /THROUGH MONDAY/
A MID LEVEL SHORT WAVE TROUGH WAS LOCATED OVER NEW YORK AND
PENNSYLVANIA THIS EVENING. THE FEATURE IS EXPECTED TO PROGRESS
EASTWARD ACROSS NEW ENGLAND OVERNIGHT. AN ASSOCIATED DEEPENING
SURFACE LOW WILL FOLLOW A SIMILAR PATH. THE OVERALL CIRCULATION
AROUND THE SYSTEM WILL CONTINUE TO DRAW DRY AIR INTO OUR REGION
FROM THE SOUTHWEST AND WEST OVERNIGHT. AS A RESULT, WE ARE
ANTICIPATING NO ADDITIONAL SHOWERS AND A GENERAL DECREASE IN
CLOUD COVER.
A GUSTY SOUTHWEST WIND IS FORECAST TO VEER TO THE WEST
OVERNIGHT. LOW TEMPERATURES ARE EXPECTED TO FAVOR THE 40S.
ON MONDAY, THE LOW PRESSURE SYSTEM WILL BE WELL NE OF THE
REGION WITH A TRAILING FRONT UP ACROSS NY/NE THEN INTO NORTH NJ.
THE FRONT MAY BRING CLOUDINESS ACROSS THE NORTHERN AREAS INTO
THE MORNING BEFORE DRIER AND COOLER AIR MOVE IN. A DECENT
PRESSURE GRADIENT ACROSS THE AREA WILL CAUSE WEST TO NORTHWEST
WINDS TO GUST AROUND 20 MPH AT TIMES INTO THE AFTERNOON. HIGH
TEMPERATURES WILL REACH THE UPPER 40S/LOW 50S FOR THE NORTH/WEST
AREAS WHILE MID 50S WILL BE ACROSS DELMARVA, METRO PHILADELPHIA
AND MUCH OF SOUTH NJ.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
SURFACE HIGH PRESSURE AND AN UPPER RIDGE BUILD OVERHEAD MONDAY
NIGHT INTO TUESDAY. IF WINDS STAY LIGHT ENOUGH, WE SHOULD GET
SOME EFFICIENT RADIATIONAL COOLING MONDAY NIGHT AND DROP
TEMPERATURES INTO THE 20S FOR MOST, OUTSIDE OF THE URBAN
CORRIDOR AND IMMEDIATE COASTAL LOCATIONS WHICH WILL SEE LOW 30S.
TUESDAY WILL BE A RATHER TRANQUIL DAY AS THE SURFACE HIGH
MEANDERS OVERHEAD AND PROVIDES MOSTLY CLEAR SKIES WITH THE
EXCEPTION OF A FEW HIGH CLOUDS. WINDS WILL STAY LIGHT AND
ULTIMATELY TURN SOUTHERLY ON THE BACK SIDE OF THE HIGH AS IT
SLIDES TO OUR EAST BY TUESDAY AFTERNOON. DESPITE THE SUN AND
SOUTHERLY RETURN FLOW, HIGHS TUESDAY TRENDED SLIGHTLY COOLER
WITH 12Z GUIDANCE AND MAY NOT REACH ABOVE THE UPPER 40S.
TEMPERATURES WILL DROP TUESDAY NIGHT, THOUGH EXACTLY HOW LOW
THEY GET WILL DEPEND ON HOW QUICKLY CLOUD COVER THICKENS AHEAD
OF WEDNESDAY'S SYSTEM. THINK THAT WE SHOULD HAVE A FEW HOURS TO
RADIATE DOWN TO JUST ABOVE FREEZING FOR MOST, THOUGH THE POCONOS
COULD REACH THE LOW 30S.
FOCUS THEN TURNS TO LOW PRESSURE THAT WILL IMPACT THE REGION ON
WEDNESDAY. THE TWO PRIMARY CONCERNS LOOK TO BE RAIN AND WIND
WITH GUIDANCE REMAINING IN GOOD AGREEMENT ON THE DYNAMICS BEING
STRONG WITH THIS SYSTEM. THE UPPER TROUGH WILL APPROACH FROM THE
WEST AND OBTAIN A NEGATIVE TILT BY WEDNESDAY EVENING. EXPECTING
THE SURFACE WARM FRONT TO LIFT THROUGH THE AREA IN THE MORNING
HOURS FOLLOWED BY THE COLD FRONT IN THE EVENING, AND RAIN SHOULD
OVERSPREAD MUCH OF THE REGION BY LATE MORNING. PWAT VALUES ARE
PROGGED TO NEAR 1 INCH, WHICH IS AROUND THE 90TH PERCENTILE FOR
THE DAY, SO WE WILL CONTINUE TO MONITOR THE POTENTIAL FOR ANY
HEAVY RAINFALL. THERE IS ALSO THE POSSIBILITY FOR A PERIOD OF
HEAVIER RAIN/A LOW TOPPED GUSTY LINE ALONG THE FRONT ITSELF WHEN
LIFT IS MAXIMIZED WITH THE IMPRESSIVE DYNAMICS IN PLAY. MODEL
CONSENSUS SUGGESTS AROUND 0.5"-1" OF RAIN FOR THE AREA AT THIS
POINT.
AS FAR AS THE WINDS ARE CONCERNED, THE PRESSURE GRADIENT WILL
BE TIGHT AHEAD OF, AND ESPECIALLY BEHIND, THE COLD FRONT WITH A
QUICK INCREASE ON ITS BACK SIDE. THE INDUCED ISALLOBARIC WIND
COMBINED WITH ANY OF THE 50+ KNOT FLOW PROGGED AT 850 MB
REACHING THE SURFACE WOULD RESULT IN THE POTENTIAL FOR SOME
STIFF WIND GUSTS. EXPECT THAT THE WINDS WILL INCREASE THROUGHOUT
THE DAY, LIKELY PEAKING IN THE EVENING/EARLY OVERNIGHT HOURS
WITH THE FRONT'S PASSAGE. NBMEXP PROB 24 HOUR GUST HAS EARLY
INDICATIONS OF GUSTS POTENTIALLY RAMPING UP TO NEAR 40-45 MPH.
LONG TERM /THURSDAY THROUGH SUNDAY/
A SURFACE HIGH IS PROGGED TO BUILD ACROSS THE OHIO VALLEY ON
THE BACK SIDE OF WEDNESDAY'S COLD FRONT, AND A TIGHT PRESSURE
GRADIENT BETWEEN THE TWO WILL LIKELY MAINTAIN SOME ELEVATED
GUSTS FOR THE DAY ON THURSDAY. VALUES UP TO 30 MPH ARE POSSIBLE
UNTIL THE GRADIENT BEGINS TO RELAX THURSDAY EVENING AS THE HIGH
MOVES CLOSER OVERHEAD. DRY AND COOLER WEATHER RETURNS FOR
THURSDAY AND FRIDAY WITH HIGHS IN THE 40S AND LOWS IN THE 20S.
BY THE WEEKEND, THE FORECAST BECOMES LESS CERTAIN AS
DETERMINISTIC GUIDANCE IS CONTINUING TO HINT AT ANOTHER LOW
PASSING OFF TO OUR NORTH AND POTENTIALLY RETURNING PRECIPITATION
CHANCES. GEFS MEMBERS DO HAVE RELATIVELY GOOD SUPPORT FOR A LOW
TRACKING SOMEWHERE ACROSS ONTARIO, BUT SIGNIFICANT RUN-TO-RUN
VARIABILITY ACROSS GUIDANCE KEEPS CONFIDENCE LOW, THUS HELD WITH
NBM FOR THIS PERIOD WHICH HAS JUST SLIGHT CHANCE POPS FOR BOTH
DAYS NEXT WEEKEND.
AVIATION /03Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TONIGHT...ANY LINGERING MVFR/IFR CEILINGS QUICKLY
IMPROVE TO VFR WITH CLOUDS SCATTERING OUT AT TIMES. SOUTHWEST TO
WEST WINDS 8- 15 KNOTS WITH GUSTS 20-25 KNOTS, DIMINISHING TO
10 KNOTS OR LESS. MODERATE CONFIDENCE.
MONDAY...VFR CEILINGS, HOWEVER CLOUD BASES MAY NEAR MVFR AT
TIMES MAINLY AT ABE AND RDG. NORTHWESTERLY WINDS INCREASING TO
12-15 KNOTS WITH GUSTS UP TO 25 KNOTS. LOW CONFIDENCE REGARDING
ANY MVFR CEILINGS.
MONDAY NIGHT...VFR WITH A CLEARING SKY. NORTHWEST WINDS
DIMINISHING TO 10 KNOTS OR LESS. MODERATE CONFIDENCE.
OUTLOOK...
TUESDAY...VFR. NORTHERLY WINDS IN THE MORNING BECOMING
SOUTHERLY IN THE AFTERNOON AT 5 KNOTS OR LESS. HIGH CONFIDENCE.
WEDNESDAY...SUB-VFR CONDITIONS EXPECTED WITH PERIODS OF RAIN.
SOUTHERLY WIND BECOMING WESTERLY IN THE EVENING WITH GUSTS
GREATER THAN 30 KNOTS POSSIBLE, ESPECIALLY IN THE EVENING.
MODERATE CONFIDENCE.
THURSDAY...CONDITIONS IMPROVE TO VFR. WESTERLY WINDS 10-15
KNOTS WITH GUSTS TO 30 KNOTS. WINDS WILL BEGIN TO DIMINISH
OVERNIGHT. HIGH CONFIDENCE
FRIDAY...VFR. WESTERLY WINDS 5-10 KNOTS. HIGH CONFIDENCE.
MARINE
WIND GUSTS HAVE DIMINISHED BELOW GALE FORCE THIS EVENING. AS A
RESULT, WE WILL DOWNGRADE THE GALE WARNING TO A SMALL CRAFT
ADVISORY. THE DEEPENING LOW THAT WILL CONTINUE TO MOVE AWAY TO
OUR NORTHEAST WILL KEEP A TIGHT PRESSURE GRADIENT ACROSS OUR
REGION INTO MONDAY. AS A RESULT, WE ARE ANTICIPATING A SOUTHWEST
TO WEST WIND 15 TO 20 KNOTS WITH GUSTS OF 25 TO 30 KNOTS
OVERNIGHT, BECOMING NORTHWEST ON MONDAY. THE SMALL CRAFT
ADVISORY WILL REMAIN IN EFFECT UNTIL MONDAY EVENING.
OUTLOOK...
TUESDAY...NO MARINE HEADLINES EXPECTED. NORTHERLY WINDS IN THE
MORNING BECOMING SOUTHERLY IN THE AFTERNOON AT 5-10 KNOTS. SEAS
2-3 FEET.
WEDNESDAY...SCA CONDITIONS LIKELY WITH GALES POSSIBLE.
SOUTHERLY WINDS 20-25 KNOTS WITH GUSTS TO 35 KNOTS. SEAS
BUILDING TO 6-8 FEET.
THURSDAY...SCA CONDITIONS LIKELY WITH GALES POSSIBLE. WESTERLY
WINDS 15-25 KNOTS WITH GUSTS TO 30 KNOTS. SEAS 6-8 FEET IN THE
MORNING SUBSIDING TO 4-6 FEET BY THE EVENING.
FRIDAY...NO MARINE HEADLINES EXPECTED. WINDS DIMINISHING TO
5-10 KNOTS. SEAS 2-3 FEET.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST MONDAY FOR ANZ430.
SMALL CRAFT ADVISORY UNTIL 10 PM EST MONDAY FOR ANZ431-450>455.
SYNOPSIS...BRUDY
NEAR TERM...IOVINO/OHARA
SHORT TERM...BRUDY
LONG TERM...BRUDY
AVIATION...BRUDY/GORSE
MARINE...BRUDY/OHARA
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