809
FXUS61 KPHI 231720
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1220 PM EST THU JAN 23 2025
SYNOPSIS
ARCTIC HIGH PRESSURE WILL REMAIN IN PLACE TO OUR WEST AND
SOUTHWEST INTO THE WEEKEND, KEEPING BELOW NORMAL TEMPERATURES
AND DRY CONDITIONS IN PLACE ACROSS THE REGION THROUGH SATURDAY.
A WEAK COLD FRONT WILL PASS THROUGH ON FRIDAY. SOUTHWESTERLY
FLOW WILL DEVELOP OVER THE WEEKEND, RESULTING IN MODERATING
TEMPERATURES BY SUNDAY AND INTO EARLY NEXT WEEK. ANOTHER COLD
FRONT MAY IMPACT THE REGION INTO THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 12:15 PM...NO CHANGES HAVE BEEN MADE TO THE EARLY
AFTERNOON UPDATE. FORECAST REMAINS ON TRACK.
FOR TODAY, PARTLY TO MOSTLY SUNNY SKIES ARE EXPECTED WITH SOME
MODERATION TO THE AIRMASS. HIGH PRESSURE MOVES OFFSHORE,
FOSTERING IN A LIGHT SOUTHERLY FLOW. SOME CLOUDS MOVE THROUGH
THE SOUTHERN AREAS AS A DEVELOPING COASTAL LOW SLIDES BY TO THE
SOUTH AND EAST. TEMPERATURES WILL TOP OUT IN THE MID TO UPPER
20S AND LOW 30S, A FEW DEGREES WARMER THAN YESTERDAY.
FOR TONIGHT, SHOULD SEE DECENT RADIATIONAL CONDITIONS AGAIN.
HOWEVER, A LIGHT WEST/SOUTHWESTERLY BREEZE AND MODERATION OF THE
AIRMASS WILL ALLOW TEMPERATURES TO BE A FEW DEGREES WARMER THAN
THIS MORNING. LOWS WILL RANGE IN THE UPPER SINGLE DIGITS IN THE
COOLER, MORE SHELTERED SPOTS, WITH LOW TO MID TEENS ELSEWHERE.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
BENIGN WEATHER AND BELOW NORMAL TEMPERATURES CONTINUING TO
CLOSE OUT THE WEEK AND INTO THE WEEKEND, BUT WITH SOME SLIGHT
IMPROVEMENT IN TEMPERATURES COMPARED TO THE FRIGID WEEK WE'VE
EXPERIENCED.
A MODESTLY AMPLIFIED TROUGH WILL APPROACH THE AREA FRIDAY AND
PASS THROUGH FRIDAY NIGHT. STRONG ZONAL FLOW WILL THEN DEVELOP
IN ITS WAKE INTO THE WEEKEND. AT THE SURFACE, A DECAYING FRONTAL
BOUNDARY WILL PASS THROUGH ON FRIDAY WITH HIGH PRESSURE
BUILDING IN FROM THE WEST AND SOUTHWEST IN ITS WAKE. THE FRONT
WILL NOT BE VERY NOTICEABLE FROM A SENSIBLE WEATHER PERSPECTIVE,
AS IT WILL MAINLY JUST BRING A SLIGHT REINFORCEMENT OF ARCTIC
AIR FOR ANOTHER 24 HOURS INTO SATURDAY BEFORE TEMPERATURES
REBOUND BACK CLOSER TO NORMAL BY SUNDAY. THE DYNAMICS ALOFT,
LACK OF ANY MOISTURE RETURN, AND DECAYING NATURE OF THE FRONT
WILL TRANSLATE TO A DRY FRONTAL PASSAGE, ALTHOUGH A SLIGHT
INCREASE IN CLOUD COVER IS ANTICIPATED. CAN'T COMPLETELY RULE
OUT A PASSING FLURRY IN THE POCONOS.
TEMPERATURE WISE, FRIDAY SHOULD SEE A SLIGHT REBOUND IN
TEMPERATURES COMPARED TO TODAY. HIGHS MAINLY IN THE UPPER 20S TO
LOW 30S. THE I- 95 CORRIDOR LOOKS TO REMAIN AT OR BELOW
FREEZING THOUGH, WITH ONLY FAR SOUTHERN NJ OR DELMARVA HAVING A
MEANINGFUL CHANCE OF RISING A COUPLE DEGREES ABOVE FREEZING.
WITH THE RESURGENCE OF ARCTIC AIR FRIDAY NIGHT, WE SHOULD SEE A
RETURN OF MORE WIDESPREAD SINGLE DIGIT LOW TEMPERATURES, AT
LEAST NORTHWEST OF I-95. FORTUNATELY, THERE WON'T BE MUCH WIND
TO CONTEND WITH. WITH THIS UPDATE, KEPT SINGLE DIGITS CONFINED
NORTHWEST OF I-95 AND FROM AROUND 10-15 DEGREES ALONG AND
SOUTHEAST OF I-95. LOW TEMPERATURES FRIDAY NIGHT WILL ULTIMATELY
DEPEND ON THE EXTENT OF THE SNOWPACK, WHICH WILL PROBABLY BE
GETTING QUITE SPARSE AND THINNED OUT NEAR AND SOUTHEAST OF I-95.
THE SNOWPACK IS ALREADY DOWN TO ABOUT T-2 INCHES IN THIS AREA,
AND IT WILL PROBABLY DIMINISH EVEN MORE WITH TEMPERATURES NEAR
30 DEGREES AND PLENTY OF SUN OVER THE NEXT 2 DAYS. THIS WILL BE
THE FACTOR LIMITING SINGLE DIGITS IN THAT REGION.
HIGH TEMPERATURES SATURDAY LIKELY REMAINING SIMILAR TO THAT OF
FRIDAY WITH INCREASING CIRRUS. FOR SATURDAY NIGHT, TEMPERATURES
WILL FINALLY REBOUND MORE CONSIDERABLY, RANGING MOSTLY FROM THE
UPPER TEENS TO LOW 20S. THIS WILL BE DUE TO SURFACE FLOW
SHIFTING SOUTHWESTERLY AND REMAINING ELEVATED OVERNIGHT, ALONG
WITH WARM ADVECTION PUSHING THE ARCTIC AIRMASS NORTH OF THE
AREA. STILL COLD (AND BELOW NORMAL), BUT A WELCOMED IMPROVEMENT
TO WHAT WE'VE EXPERIENCED THE PAST FEW DAYS!
LONG TERM /SUNDAY THROUGH WEDNESDAY/
THE EXTENDED PERIOD LOOKS TO START WITH ZONAL FLOW ALOFT ACROSS
THE NORTHEAST, WITH A CLOSED UPPER-LEVEL LOW OVER THE HUDSON
BAY. THIS FEATURE LOOKS TO MEANDER SOUTHEAST INTO PORTIONS OF
QUEBEC THROUGH THE MIDDLE OF THE WEEK. AS IT DOES SO, SUBTLE
SHORTWAVES WILL LIKELY PASS THROUGH OUR AREA, PARTICULARLY
TUESDAY AND BEYOND.
AT THE SURFACE, HIGH PRESSURE LOOKS TO INITIALLY BE IN CONTROL
WITH LOW PRESSURE CONFINED WELL TO OUR NORTH. THERE MAY BE A
COUPLE OF WEAK FRONTAL PASSAGES DURING THE EARLY PART OF THE
WEEK, BUT AS OF RIGHT NOW IT APPEARS THEY WILL BE DRY, WITH THE
EXCEPTION OF MAYBE A FEW FLURRIES IN THE POCONOS.
THERE IS AGREEMENT AMONGST THE MODELS THAT AN AREA OF LOW
PRESSURE WILL DEVELOP IN THE GREAT LAKES VICINITY, PASSING TO
OUR NORTH TUESDAY INTO WEDNESDAY. A TRAILING COLD FRONT COULD
BRING INCREASED CLOUDINESS TO THE REGION. THERE IS A NON-ZERO
CHANCE THAT A LITTLE LIGHT RAIN OR SNOW COULD ACCOMPANY THIS
PASSAGE AS WELL, THOUGH CONFIDENCE IS NOT HIGH ON THAT FRONT.
TEMPERATURES THROUGH MOST OF THE EXTENDED PERIOD LOOK TO BE
FAIRLY CLOSE TO SEASONAL NORMALS ACROSS THE AREA WITH ONLY MINOR
FLUCTUATIONS FROM DAY-TO-DAY.
AVIATION /17Z THURSDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON...VFR WITH PARTLY TO MOSTLY SUNNY SKIES.
WEST-SOUTHWEST WINDS AROUND 3 TO 8 KT. HIGH CONFIDENCE.
TONIGHT...VFR/SKC. WEST-SOUTHWEST WINDS AROUND 5 KTS OR LESS.
HIGH CONFIDENCE.
FRIDAY...VFR WITH A FEW CLOUDS DURING THE AFTERNOON. WEST-
NORTHWEST WINDS AROUND 5-10 KT. HIGH CONFIDENCE.
OUTLOOK...
FRIDAY NIGHT THROUGH MONDAY...VFR. NO SIGNIFICANT WEATHER.
WINDS AROUND 10 KTS OR LESS.
MARINE
SUB-SCA CONDITIONS THROUGH TONIGHT ARE EXPECTED. WINDS WILL BE
AROUND 5-10 KT TODAY, INCREASING TO AROUND 10-20 KT TONIGHT.
SEAS 1 TO 3 FEET. SOME LIGHT FREEZING SPRAY IS POSSIBLE ON THE
OUTER WATERS WITH THE INCREASE IN WINDS TONIGHT.
OUTLOOK...
FRIDAY THROUGH MONDAY...NO MARINE HAZARDS ANTICIPATED. WINDS
REMAIN AROUND 10-20 KTS AND SEAS 2-4 FEET. A CHANCE OF SOME
LIGHT FREEZING SPRAY FRIDAY MORNING. WE SHOULD SEE A REDUCTION
IN ICE COVERAGE INTO THE WEEKEND AND EARLY NEXT WEEK AS
TEMPERATURES BEGIN TO MODERATE COMPARED TO THIS PAST WEEK.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...STAARMANN
NEAR TERM...DESILVA/HOEFLICH
SHORT TERM...STAARMANN
LONG TERM...COOPER
AVIATION...DESILVA/HOEFLICH/STAARMANN
MARINE...DESILVA/HOEFLICH/STAARMANN
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