233
FXUS61 KPHI 122202
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
602 PM EDT MON OCT 12 2026
WHAT HAS CHANGED
ADDED A NEW KEY MESSAGE (1) AND UPDATED KEY MESSAGE 3.
KEY MESSAGES
1. SURGE OF WARMTH AND HUMIDITY THROUGH WEDNESDAY AHEAD OF A COLD
FRONT.
2. A STRONG COLD FRONT FRIDAY BRINGS AN END TO THE WARMTH AS MUCH
COLDER AIR ARRIVES FOR THE WEEKEND.
3. SPOTTY MINOR COASTAL FLOODING WILL BE POSSIBLE WITH THE TUESDAY
MORNING HIGH TIDE CYCLE.
DISCUSSION
KEY MESSAGE 1...SURGE OF WARMTH AND HUMIDITY THROUGH WEDNESDAY AHEAD
OF A COLD FRONT.
A FRONTAL ZONE DRAPED TO OUR NORTH TUESDAY WILL RESULT IN SURFACE
LOW PRESSURE RIDING ALONG IT TUESDAY NIGHT AND WEDNESDAY. THIS WILL
PULL A COLD FRONT ACROSS OUR AREA BY LATER WEDNESDAY. AHEAD OF THIS
FEATURE, SOUTHERLY FLOW WILL BOOST THE LOW-LEVEL WARM AIR ADVECTION
AND THIS RESULTS IN MUCH WARMER AIR SURGING INTO OUR AREA THROUGH
WEDNESDAY. HIGH TEMPERATURES WILL NEAR 80 DEGREES FOR MANY AREAS ON
TUESDAY, THEN INTO THE LOW TO EVEN SOME MID 80S ON WEDNESDAY. IN
ADDITION, DEW POINTS WILL INCREASE BACK THROUGH THE 60S TUESDAY AND
WEDNESDAY, WITH THEM PEAKING ON WEDNESDAY (NEAR 70F FOR PARTS OF THE
AREA) AHEAD OF THE AFOREMENTIONED FRONT. THIS WILL RESULT IN A MUCH
MORE HUMID FEEL OVER THE NEXT FEW DAYS, WITH IT BEING THE MOST HUMID
ON WEDNESDAY (HEAT INDEX VALUES SHOULD APPROACH 90F FOR AREAS FROM
ABOUT PHILADELPHIA SOUTH AND EAST; AWAY FROM THE COAST). THERE DOES
NOT APPEAR TO BE ALL THAT MUCH IN THE WAY OF FORCING FOR ASCENT WITH
THE FRONT AS IT ARRIVES BY LATER WEDNESDAY, THEREFORE JUST A LOW
CHANCE (20-30 PERCENT) FOR SHOWERS AS OF NOW. THE DEW POINTS WILL
FALL FROM NORTH TO SOUTH LATER WEDNESDAY NIGHT INTO THURSDAY AS THE
FRONT SETTLES SOUTHWARD AND THE WINDS TURN OUT OF THE NORTH AND
NORTHEAST. THE FRONT HOWEVER MAY NOT COMPLETELY CLEAR OUR
REGION.
KEY MESSAGE 2...A STRONG COLD FRONT FRIDAY BRINGS AN END TO THE
WARMTH AS MUCH COLDER AIR ARRIVES FOR THE WEEKEND.
A POTENT UPPER-LEVEL TROUGH IS FORECAST TO ARRIVE ACROSS THE EAST
DURING FRIDAY, THEN GRADUALLY LIFT OUT OVER THE WEEKEND. THIS WILL
DRIVE SURFACE LOW PRESSURE JUST NORTH OF OUR AREA FRIDAY WITH AN
ASSOCIATED STRONG COLD FRONT SWEEPING THROUGH.
A MILD AND INCREASINGLY MOIST AIR MASS AHEAD OF THIS FEATURE WILL
PROVIDE SOME INSTABILITY AS THE STRONG COLD FRONT ARRIVES ON FRIDAY.
LARGE SCALE FORCING FOR ASCENT WILL INCREASE WITH THE ARRIVAL OF THE
ROBUST UPPER-LEVEL TROUGH AND COLD FRONT, THEREFORE SHOWERS WILL
INCREASE FOR A TIME (PEAKING ON FRIDAY). SOME SHOWERS THOUGH LOOK TO
DEVELOP THURSDAY NIGHT AHEAD OF THE MAIN COLD FRONT. SOME
THUNDERSTORMS CANNOT BE RULED OUT GIVEN THE STRENGTH OF THE SYSTEM,
HOWEVER THIS WILL ULTIMATELY DEPEND ON THE MAGNITUDE OF THE
INSTABILITY AND TIMING OF THE COLD FRONT. IN THE WAKE OF THE COLD
FRONT, STRONG COLD AIR ADVECTION OCCURS AND THIS WILL RESULT IN MUCH
COLDER TEMPERATURES FOR THE WEEKEND. AS OF NOW, HIGH TEMPERATURES
BOTH SATURDAY AND SUNDAY LOOK TO STRUGGLE TO GET OUT OF THE 50S
(COLDER IN THE HIGHER TERRAIN). A GUSTY WIND SATURDAY DUE TO COLD
AIR ADVECTION AND A TIGHTENED PRESSURE GRADIENT WILL ADD TO THE
CHILL. IF THE WIND DROPS OFF ENOUGH SATURDAY NIGHT, SOME FROST OR
FREEZING TEMPERATURES WILL BECOME A CONCERN FOR PORTIONS OF OUR
AREA. THE AIR MASS THEN STARTS TO MODIFY EARLY NEXT WEEK.
KEY MESSAGE 3...SPOTTY MINOR COASTAL FLOODING WILL BE POSSIBLE
WITH THE TUESDAY MORNING HIGH TIDE CYCLE.
THE COASTAL FLOOD ADVISORY EXPIRED AT 5 PM FOR THE BACK BAY
AREAS OF SUSSEX COUNTY, DE AND OCEAN COUNTY, NJ (MAINLY BARNEGAT
BAY). THERE WILL BE THE POTENTIAL FOR SOME ADDITIONAL MINOR
COASTAL FLOODING WITH TUESDAY MORNING'S HIGH TIDE CYCLE FOR
PLACES ALONG THE ATLANTIC COAST AND DELAWARE BAY BUT IT SHOULD
BE MORE SPOTTY IN NATURE AS WE GET FARTHER WAY FROM THE NEW
MOON.
NO TIDAL FLOODING CONCERNS EXPECTED ALONG THE CHESAPEAKE BAY.
AVIATION /21Z MONDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR WITH DECREASING CLOUDS BUT FOG IS POSSIBLE AFTER
MIDNIGHT. INSERTED TEMPO GROUPS FOR MANY TERMINALS. HIGH CONFID
EXCEPT WITH REGARDS TO FOR FORMATION. NW WINDS 5 TO 10 KTS.
EARLY THEN CALM OVERNIGHT.
TUESDAY... VFR EXPECTED. SOUTHWEST WINDS INCREASING 5 TO 10
KNOTS. HIGH CONFID.
OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY...VFR.
THURSDAY AND FRIDAY...A PERIOD OF SUB-VFR CONDITIONS POSSIBLE WITH
SHOWERS. GUSTY SOUTHWEST TO WEST WINDS ON FRIDAY.
SATURDAY...VFR. GUSTY NORTHWEST WINDS.
MARINE
SCA CONDITIONS CONTINUE ON THE WATERS THIS AFTERNOON AND THE
MARINE FLAGS WILL CONTINUE AS IS. IT'S POSSIBLE THAT THE SEAS
MAY DROP BELOW 5 FT BEFORE THE PRESENT FLAG EXPIRATION TIME
HOWEVER. FAIR TONIGHT AND TUESDAY.
OUTLOOK...
TUESDAY NIGHT THROUGH THURSDAY...NO MARINE HAZARDS ARE ANTICIPATED.
FRIDAY AND SATURDAY...SMALL CRAFT ADVISORY CONDITIONS PROBABLE, WITH
A PERIOD OF GALE-FORCE WIND GUSTS POSSIBLE.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT TUESDAY FOR ANZ450>452.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ453>455.
DISCUSSION...FITZSIMMONS/GORSE
AVIATION...GORSE/PO
MARINE...GORSE/PO
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