874
FXUS61 KPHI 040715
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
315 AM EDT WED OCT 4 2023
SYNOPSIS
HIGH PRESSURE WILL BECOME MORE CENTERED TO OUR EAST AND NORTHEAST
THROUGH TONIGHT, HOWEVER IT WILL CONTINUE TO EXTEND ACROSS OUR
REGION. THE HIGH WEAKENS AND SHIFTS MORE TO OUR NORTHEAST WEDNESDAY
INTO THURSDAY. A STRONG COLD FRONT MOVES THROUGH ON SATURDAY, WHICH
BRINGS A COLDER AND MUCH DRIER AIR MASS INTO OUR REGION OVER THE
WEEKEND THROUGH EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
A CLEAR SKY AND LIGHT WIND ALLOWED AREAS OF FOG TO DEVELOP DURING
THE NIGHT, MAINLY IN THE VALLEYS OF EASTERN PENNSYLVANIA AND
NORTHERN NEW JERSEY, AND IN THE PINE BARRENS OF SOUTHERN NEW JERSEY.
THE FOG IS EXPECTED TO LIFT AND DISSIPATE DURING THE MID MORNING
HOURS.
HIGH PRESSURE EXTENDED FROM THE SOUTHEASTERN STATES UP INTO NEW
ENGLAND EARLY THIS MORNING. THE AIR MASS WILL BUILD SLOWLY EASTWARD
TODAY AND TONIGHT, BRINGING CONTINUED DRY WEATHER TO OUR REGION.
A LIGHT SOUTHERLY WIND IS ANTICIPATED TO DEVELOP FOR THIS AFTERNOON,
WITH A LIGHT AND VARIABLE WIND RETURNING FOR TONIGHT. MAXIMUM
TEMPERATURES THIS AFTERNOON WILL AGAIN BE WELL ABOVE NORMAL, WITH
HIGHS MOSTLY FROM THE UPPER 70S INTO THE MIDDLE 80S. TONIGHT'S LOWS
SHOULD FAVOR THE 50S WITH SOME FOG EXPECTED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
TEMPERATURES STILL ON THE MILD SIDE, HOWEVER A DOWNWARD TREND BEGINS.
DESPITE HIGH PRESSURE BECOMING MORE AND MORE CENTERED TO OUR
NORTHEAST, IT WILL STILL REMAIN IN CONTROL OF OUR WEATHER THROUGH
THURSDAY. WHILE SOME HIGH CLOUDS MAY START TO ARRIVE THURSDAY
MORNING, CONDITIONS LOOK FAVORABLE ONCE AGAIN FOR EARLY MORNING
PATCHY FOG ESPECIALLY IN PARTS OF EASTERN PENNSYLVANIA AND NORTHERN
NEW JERSEY. WE WILL BEGIN TO SEE SOME SIGNS OF CHANGE ON THURSDAY,
AS THERE SHOULD BE AT LEAST SOME INCREASE IN HIGH CLOUDS BY THE END
OF THE DAY. OVERALL THOUGH, EXPECT ONE MORE MILD AND DRY DAY WITH
HIGHS MOSTLY IN THE MID TO UPPER 70S. MORE OF AN EAST TO EAST-
SOUTHEAST WIND THOUGH WILL KEEP IN COOLER ALONG THE COAST.
THICKER CLOUDS WILL START TO OVERSPREAD OUR REGION THURSDAY NIGHT
INTO FRIDAY MORNING. THE LOW-LEVEL FLOW WILL BE FROM THE EAST TO
SOUTHEAST, AND THIS WILL START TO INCREASE THE LOWER LEVEL MOISTURE
WITH TIME. SOME STRATUS MAY DEVELOP LATER THURSDAY NIGHT AND FRIDAY
MORNING AS MOISTURE ADVECTION TEAMS UP WITH SOME INCREASE IN THE
WARM AIR ADVECTION. THIS COULD ALSO RESULT IN A FEW SHOWERS OR EVEN
SOME DRIZZLE ASSUMING THE STRATUS FORMS. CONFIDENCE REMAINS LOW ON
HOW THIS PLAYS OUT THEREFORE KEPT THE POPS THROUGH MIDDAY FRIDAY ON
THE LOW SIDE. GUIDANCE GENERALLY AGREES THAT A WEAK SHORTWAVE WILL
BE APPROACHING OUR AREA FROM THE WEST-SOUTHWEST FRIDAY AFTERNOON,
WELL IN ADVANCE OF THE MAIN UPPER-LEVEL TROUGH AND ASSOCIATED
SURFACE COLD FRONT TRACKING ACROSS THE GREAT LAKES AND THE OHIO
VALLEY. DEEPER MOISTURE AND FORCING AS WELL AS INSTABILITY LOOKS
LIKE IT WILL BE LIMITED AT THAT TIME, SO WHILE SOME THUNDER CANNOT
BE COMPLETELY RULED OUT, OPTED TO KEEP A MENTION OUT FOR NOW.
CONDITIONS WILL STILL BE MILD AND EVEN MORE HUMID WITH HIGHS IN THE
70S. THE SHOWERS SHOULD THEN START TO INCREASE SOME FRIDAY NIGHT,
ESPECIALLY ACROSS THE WESTERN AREAS.
LONG TERM /SATURDAY THROUGH TUESDAY/
SUMMARY...TURNING MUCH COOLER TO COLDER AND EVENTUALLY MUCH
DRIER OVER THE WEEKEND INTO EARLY NEXT WEEK. SHOWERS SATURDAY AS
A STRONG COLD FRONT MOVES THROUGH, THEN MAINLY DRY.
SYNOPTIC OVERVIEW...AN UPPER-LEVEL TROUGH LOOKS TO CLOSE OFF AS IT
SHIFTS ACROSS THE GREAT LAKES AND VICINITY SATURDAY, THEN REMAINS
ACROSS THE EAST SUNDAY THROUGH EARLY NEXT WEEK. A STRONG COLD FRONT
CROSSES OUR AREA SATURDAY, THEN CYCLONIC FLOW AND MUCH COOLER TO
COLDER AIR DOMINATES THROUGH EARLY NEXT WEEK.
FOR SATURDAY...A SHARP UPPER-LEVEL TROUGH IS FORECAST TO CLOSE OFF
ACROSS THE GREAT LAKES SATURDAY AS IT GRADUALLY SHIFTS EASTWARD. A
STRONG SHORTWAVE IS FORECAST TO ROUND ITS BASE ACROSS THE UPPER OHIO
VALLEY AND THE EASTERN GREAT LAKES. AS SURFACE LOW PRESSURE OCCLUDES
ACROSS THE EASTERN GREAT LAKES, A TRAILING COLD FRONT IS FORECAST TO
CROSS OUR AREA DURING SATURDAY. FORCING FOR ASCENT WITH THE COLD
FRONT AND TROUGH ALOFT WILL MAINTAIN SHOWERS. THE STRONGEST FORCING
MAY REMAIN TO OUR WEST GIVEN THE MAIN TROUGH HANGING BACK WELL TO
OUR WEST UNTIL SATURDAY EVENING. ISOLATED THUNDER CANNOT BE RULED
OUT, ESPECIALLY ACROSS THE NORTHERN AREAS AS SOME ENHANCEMENT TO A
BAND OF SHOWERS MAY OCCUR IN THE AFTERNOON AS THE MAIN TROUGH STARTS
TO ARRIVE. IT IS THERE WERE SOME GUIDANCE SHOWS AN AXIS OF WEAK
INSTABILITY POTENTIALLY BECOMING MORE FOCUSED. GIVEN THAT THE
INSTABILITY LOOKS TO BE ON THE LIMITED SIDE AND THE STRONGEST FLOW
HANGS BACK TO OUR WEST, SEVERE THUNDERSTORMS ARE NOT ANTICIPATED.
TEMPERATURES WILL DEPEND ON HOW QUICKLY THE FRONT CLEARS THE REGION,
BUT MAY FEATURE HIGHS OCCURRING EARLIER IN THE DAY. SOUTHERLY WINDS
WILL INCREASE SOME AHEAD OF THE COLD FRONT, THEN QUICKLY BECOME WEST
TO NORTHWEST IN THE WAKE OF THE COLD FRONT AND INCREASE MORE AS
STRONG COLD AIR ADVECTION TAKES OVER. MUCH COOLER TO COLDER AIR AND
TUMBLING DEW POINTS WILL OVERSPREAD THE AREA IN THE WAKE OF THE COLD
FRONT, AND ANY SHOWERS SHOULD BE ENDING SATURDAY NIGHT.
FOR SUNDAY THROUGH TUESDAY...AN UPPER-LEVEL TROUGH/CLOSED LOW IS
FORECAST TO DOMINATE THE EAST. CYCLONIC FLOW ALONG WITH COLD AIR
ALOFT MAY RESULT IN STRATOCUMULUS DEVELOPING OVERHEAD OR SPREADING
IN FROM THE WEST AT LEAST DURING SUNDAY AND MONDAY. A TIGHTENED
PRESSURE GRADIENT COUPLED WITH DEEPER MIXING WITHIN THE BOUNDARY
LAYER WILL RESULT IN A CHILLY BREEZE WHICH WILL ALSO BE GUSTY FOR
MUCH OF THIS TIME FRAME. THE FLOW HOWEVER MAY START TO BACK TO THE
WEST-SOUTHWEST MONDAY AND TUESDAY AS THE CLOSED LOW MAY SHIFT
WESTWARD SOME ACROSS THE GREAT LAKES REGION. THERE SHOULD BE SOME
LAKE RESPONSE, HOWEVER MUCH OF THOSE SHOWERS SHOULD REMAIN CLOSER TO
THE EASTERN GREAT LAKES ESPECIALLY AS THE FLOW BACKS MORE WITH TIME.
STILL CANNOT RULE OUT SOME BRIEF SHOWERS OR SPRINKLES SUNDAY INTO
MONDAY MANLY FOR THE POCONO REGION. HIGH TEMPERATURES IN THE 50S TO
LOW 60S SUNDAY AND MONDAY (SOME 40S IN THE POCONOS), THEN A LITTLE
MILDER TUESDAY AS THE AIR MASS STARTS TO SLIGHTLY WARM ALOFT.
WIDESPREAD 40S AT NIGHT ARE FORECAST, WITH EVEN SOME UPPER 30S
MAINLY IN THE POCONOS.
AVIATION /07Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS...
TODAY...EARLY MORNING RESTRICTIONS ARE EXPECTED DUE TO FOG.
OTHERWISE, VFR UNDER A MOSTLY CLEAR SKY FROM LATE THIS MORNING INTO
THIS AFTERNOON. VARIABLE WIND 5 KNOTS OR LESS, BECOMING SOUTHERLY 4
TO 8 KNOTS IN THE AFTERNOON. MEDIUM CONFIDENCE IN THE EXTENT OF THE
MORNING FOG, OTHERWISE HIGH CONFIDENCE IN VFR CONDITIONS FOR THE
LATE MORNING AND AFTERNOON.
TONIGHT...VFR UNDER A MOSTLY CLEAR SKY. AREAS OF FOG MAY IMPACT SOME
OF OUR TAF SITES AFTER 06Z. VARIABLE WIND 5 KNOTS OR LESS. MEDIUM TO
HIGH CONFIDENCE.
OUTLOOK...
THURSDAY...VFR. SOME LOW CLOUDS MAY DEVELOP HOWEVER LATE AT NIGHT.
LIGHT AND VARIABLE WINDS BECOMING SOUTHEASTERLY 5-10 KNOTS. LOW
CONFIDENCE REGARDING LOW CLOUD DEVELOPMENT.
FRIDAY...A PERIOD OF MVFR, POSSIBLY IFR, WITH A CHANCE FOR SOME
SHOWERS DURING THE DAY AND ESPECIALLY AT NIGHT. SOUTHEAST WINDS
5-10 KNOTS. LOW CONFIDENCE.
SATURDAY...MVFR/IFR CONDITIONS WITH SHOWERS. SOUTHWEST WINDS
5-10 KNOTS BECOMING WEST TO NORTHWEST 10-15 KNOTS AND POSSIBLY
GUSTY. LOW CONFIDENCE.
SUNDAY...MAINLY VFR. WESTERLY WINDS 10-20 KNOTS WITH GUSTS TO AROUND
25 KNOTS. THE WINDS SHOULD DIMINISH SOME AT NIGHT. MODERATE
CONFIDENCE.
MARINE
A LIGHT AND VARIABLE WIND THIS MORNING IS FORECAST TO BECOME SOUTH
TO SOUTHEAST 5 TO 10 KNOTS THIS AFTERNOON. THE WIND IS EXPECTED TO
BACK TOWARD THE EAST TONIGHT. WAVE HEIGHTS ON OUR OCEAN WATERS ARE
EXPECTED TO BE 2 TO 3 FEET, WITH WAVES ON DELAWARE BAY AT 2 FEET OR
LESS.
OUTLOOK...
THURSDAY...THE CONDITIONS ARE ANTICIPATED TO BE BELOW SMALL
CRAFT ADVISORY CRITERIA.
FRIDAY AND SATURDAY...SMALL CRAFT ADVISORY PROBABLE, MAINLY DUE TO
SEAS ON THE OCEAN ZONES THAT MAY BUILD TO 5 FEET FRIDAY NIGHT THEN
TO 5-7 FEET SATURDAY. SOUTHEAST TO SOUTHWEST WINDS WILL INCREASE
SOME, HOWEVER THE STRONGEST WINDS (POSSIBLY GUSTING TO 25-30 KNOTS)
SHOULD OCCUR SATURDAY WITH A WIND SHIFT FROM THE WEST AND NORTHWEST
IN THE WAKE OF A STRONG COLD FRONT.
SUNDAY...SMALL CRAFT ADVISORY CONDITIONS PROBABLE DUE TO GUSTY WINDS
AND ELEVATED SEAS.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...GORSE
NEAR TERM...IOVINO
SHORT TERM...DODD/GORSE
LONG TERM...GORSE
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
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