904
FXUS61 KPHI 211804
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
204 PM EDT MON SEP 21 2026
WHAT HAS CHANGED
COASTAL FLOOD HEADLINES HAVE BEEN ISSUED. A COASTAL FLOOD ADVISORY
IS IN EFFECT FOR TOMORROW EVENING'S HIGH TIDE FOR COASTAL COUNTIES
SOUTH OF BARNEGAT INLET AND FOR KENT COUNTY, DE. FOR THOSE SAME
AREAS, A COASTAL FLOOD WATCH IS NOW IN EFFECT FOR WEDNESDAY AND
THURSDAY EVENING'S HIGH TIDE AS MODERATE TIDAL FLOODING IS
POSSIBLE.
KEY MESSAGES
1. A FRONTAL BOUNDARY SOUTH OF THE REGION WILL KEEP RAIN
CHANCES AROUND THROUGH MID-WEEK, ESPECIALLY ACROSS SOUTHERN
PORTIONS OF THE AREA.
2. A CLOSED MID-LEVEL LOW EJECTING FROM THE OHIO VALLEY IS
EXPECTED TO LEAD TO THE DEVELOPMENT OF A SURFACE LOW OFF THE
EASTERN SEABOARD DURING THE MIDDLE AND LATTER PARTS OF THIS
WEEK. DEPENDING ON THE TRACK OF THE LOW, IT COULD BRING
INCREASED RAINFALL CHANCES TO THE REGION.
3. MULTIPLE ROUNDS OF POTENTIALLY SIGNIFICANT TIDAL FLOODING
EXPECTED FOR THIS WEEK. THE FIRST BATCH OF COASTAL FLOOD
HEADLINES HAVE BEEN ISSUED WITH MORE LIKELY TO COME.
DISCUSSION
KEY MESSAGE 1...A FRONTAL BOUNDARY SOUTH OF THE REGION WILL
KEEP RAIN CHANCES AROUND THROUGH MID-WEEK, ESPECIALLY ACROSS
SOUTHERN PORTIONS OF THE AREA.
THE COLD FRONT THAT CROSSED THROUGH OUR REGION SUNDAY NIGHT IS
EXPECTED TO STALL TO OUR SOUTH TODAY, AND REMAIN THERE THROUGH
TUESDAY. IT CONTINUES TO LOOK LIKE IT WILL LIFT A LITTLE CLOSER
TO OUR REGION MONDAY NIGHT INTO TUESDAY MORNING AS A WARM
FRONT, BUT REMAIN JUST SOUTH OF THE AREA. DUE TO THE CLOSER
PROXIMITY, AND A MID LEVEL SHORT WAVE TROUGH, MEAN THAT THAT
PERIOD WILL HAVE THE HIGHEST CHANCE FOR RAIN ACROSS OUR REGION.
GIVEN THAT OUR LOW WILL BE ON THE COOL SIDE OF THE FRONT,
SHOWERS ARE GOING TO BE THE MAIN MODE OF ANY PRECIPITATION.
HOWEVER, ISOLATED, EMBEDDED THUNDERSTORMS WILL BE POSSIBLE OVER
DELMARVA, PARTICULARLY DURING THE DAY ON TUESDAY.
FOR WEDNESDAY INTO THURSDAY, THE FRONT SHOULD AGAIN BE ON THE
MOVE SOUTHWARD, LESSENING RAIN CHANCES ACROSS THE AREA.
CONFIDENCE IS HIGH THAT TEMPERATURES WILL BE BELOW NORMAL
STARTING TUESDAY. IN FACT, TEMPERATURES WILL LIKELY STRUGGLE TO
GET OUT OF THE 60S AREAWIDE THROUGH MOST OF THIS WEEK.
KEY MESSAGE 2...A CLOSED MID-LEVEL LOW EJECTING FROM THE OHIO
VALLEY IS EXPECTED TO LEAD TO THE DEVELOPMENT OF A SURFACE LOW
OFF THE EASTERN SEABOARD DURING THE MIDDLE AND LATTER PARTS OF
THIS WEEK. DEPENDING ON THE TRACK OF THE LOW, IT COULD BRING
INCREASED RAINFALL CHANCES TO THE REGION.
MOST OF THE MODELS CAME INTO BETTER AGREEMENT ON THE TRACK AND
THE EVOLUTION OF THE COASTAL LOW THROUGH THURSDAY. THROUGH THIS
TIME, THE CENTER OF THE LOW SHOULD STAY FAR ENOUGH OFF SHORE
THAT RAIN CHANCES ACROSS OUR REGION WILL BE VERY LOW, EXCEPT AT
IMMEDIATE COASTAL AREAS. HOWEVER, IT LOOKS TO BE A DEEP AND
INTENSE LOW, SO EXPECT A LARGE PRESSURE GRADIENT, EVEN FOR
INLAND AREAS, AND THUS BREEZY TO WINDY CONDITIONS. FOR COASTAL
AREAS, WE COULD GET CLOSE TO WIND ADVISORY THRESHOLDS,
PARTICULARLY LATER IN THE DAY ON WEDNESDAY THROUGH THURSDAY.
FRIDAY INTO THE WEEKEND, SOME MODELS HAVE THIS BECOMING A CUTOFF
LOW AND RETROGRADING EASTWARD. NOTABLY THOUGH, THIS SOLUTION IS
PRIMARILY WITH THE DETERMINISTIC, PHYSICAL EQUATION MODELS.
SEVERAL ENSEMBLE MEMBERS AND SOME OF THE MAIN AI MODELS DEPICT
THIS LOW CONTINUING NORTHEASTWARD. ALL THAT BEING SAID, THE
FORECAST, PARTICULARLY THE RAIN AND WIND FORECAST, IS VERY
UNCERTAIN FROM FRIDAY ONWARD.
KEY MESSAGE 3...MULTIPLE ROUNDS OF POTENTIALLY SIGNIFICANT TIDAL
FLOODING EXPECTED FOR THIS WEEK. THE FIRST BATCH OF COASTAL FLOOD
HEADLINES HAVE BEEN ISSUED WITH MORE LIKELY TO COME.
WITH A SLOW MOVING COASTAL STORM INCREASINGLY LIKELY, THE THREAT FOR
TIDAL FLOODING HAS INCREASED. STRONG ONSHORE FLOW THAT IS PROJECTED
TO LAST FOR SEVERAL DAYS WILL RESULT IN WATER PILING UP ACROSS TIDAL
TRIBUTARIES AND WITHIN BACK BAYS OF COASTAL COMMUNITIES. TIDAL
LEVELS WILL ALSO BE ENHANCED WITH ASTRONOMICAL TIDES INCREASING WITH
THE UPCOMING FULL MOON ON SATURDAY. THIS COMBINATION OF FACTORS WILL
LEAD TO WIDESPREAD TIDAL FLOODING, SOME OF WHICH COULD GET TO THE
MODERATE STAGE. WHILE NOT CURRENTLY FORECAST, THE THREAT FOR MAJOR
FLOODING IS NOT OFF THE TABLE, ESPECIALLY GETTING NEAR THE FULL
MOON.
MINOR TIDAL FLOODING BEGINS AS EARLY AS TOMORROW AFTERNOON AND
EVENING FOR SOME LOCATIONS. A COASTAL FLOOD ADVISORY WAS ISSUED FOR
OCEAN, ATLANTIC, AND CAPE MAY COUNTY IN NEW JERSEY AND KENT AND
SUSSEX COUNTY IN DELAWARE. FOR THOSE SAME AREAS, TIDE LEVELS ARE
EXPECTED TO INCREASE FOR WEDNESDAY AND THURSDAY, POTENTIALLY GETTING
TO MODERATE STAGE. A COASTAL FLOOD WATCH WAS ISSUED FOR WEDNESDAY
AND THURSDAY EVENING'S HIGH TIDE. MODERATE TIDAL FLOODING COULD EVEN
CONTINUE INTO THE WEEKEND. AS MENTIONED ABOVE, CANNOT RULE OUT TIDE
LEVELS REACHING MAJOR, GIVEN THE SETUP.
FOR THE REST OF THE NJ COAST NORTH OF BARNEGAT INLET, TIDE LEVELS
ARE CURRENTLY FORECAST TO REACH MINOR ON WEDNESDAY AND THURSDAY.
COASTAL FLOOD ADVISORIES LIKELY WILL BE NEEDED, BUT TIDE LEVELS ARE
CURRENTLY FORECAST TO STAY BELOW MODERATE AT THIS TIME AND LOWER
WATER LEVELS THAN IN AREAS IN SOUTHERN DELAWARE AND SOUTH JERSEY.
THE SAME GOES FOR THE NEW JERSEY SIDE OF DELAWARE BAY AND TIDAL
DELAWARE RIVER.
WIDESPREAD MINOR TIDAL FLOODING IS NOT CURRENTLY EXPECTED WITHIN THE
CHESAPEAKE BAY. USUALLY, STRONG NORTHEAST WINDS DO NOT RESULT IN
TIDAL FLOODING IN THESE AREAS.
IN ADDITION TO COASTAL FLOODING, SEVERAL DAYS OF ONSHORE FLOW AND
HIGH WAVES WILL LIKELY RESULT IN BEACH EROSION AT THE JERSEY SHORE
AND DELAWARE BEACHES.
AVIATION /18Z MONDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
FOR KPHL, KPNE, KILG, KTTN, KABE, AND KRDG...EXPECT PREVAILING
VFR CONDITIONS THROUGH THE DAY. A BRIEF PERIOD OF MVFR CEILINGS
IS POSSIBLE THIS AFTERNOON FOR KPHL AND KILG, BUT ARE EXPECTED
TO LIFT THIS EVENING. NEAR OR AFTER 05Z, MORE MVFR CEILINGS,
AND AN ADDITIONAL ROUND OF RAIN WILL LIKELY MOVE THROUGH THE
REGION. ONCE THE MVFR CEILINGS MOVE IN, EXPECT THAT TO BE THE
CONTROLLING FACTOR IN FLIGHT CATEGORY THROUGH TUESDAY.
NORTHEASTERLY WINDS AROUND 10KT, THOUGH OCCASIONAL GUSTS UP TO
20 KT WILL BE POSSIBLE. GUSTS UP TO AROUND 20 KTS WILL BECOME
MORE FREQUENT FOR DAYTIME TUESDAY.
FOR KMIV AND KACY...PREVAILING MVFR CEILINGS EXPECTED THROUGH
TUESDAY. IFR CEILINGS POSSIBLE AT TIMES, ESPECIALLY AFTER 21Z.
NORTHEASTERLY WIND GUSTS AT OR JUST ABOVE 20KT WILL BE POSSIBLE,
PARTICULARLY THROUGH 21Z THIS AFTERNOON, THEN AFTER 09Z TUESDAY.
OUTLOOK...
WEDNESDAY THROUGH FRIDAY...WHILE UNCERTAINTY IS HIGH, SUB-VFR
CONDITIONS WILL REMAIN POSSIBLE AT TIMES IN RAIN OR LOW CLOUDS.
GUSTY NORTHEAST WINDS ARE POSSIBLE.
MARINE
SMALL CRAFT ADVISORY CONDITIONS CONTINUE TO DEVELOP ON THE
ATLANTIC COASTAL WATERS, AND WILL DEVELOP BY TUESDAY MORNING
FOR THE DELAWARE BAY. EVEN THOUGH THIS IS AN UNUSUAL WIND
DIRECTION FOR SCA CONDITIONS ON THE BAY, MULTIPLE MODELS DEPICT
A SEVERAL HOUR PERIOD OF WIND GUSTS AT OR ABOVE 25 KT, SO HAVE
ISSUED THE SCA FOR THE BAY FROM TUESDAY MORNING THROUGH TUESDAY
NIGHT.
GALES ARE LOOKING INCREASINGLY LIKELY FOR AT LEAST A PERIOD OF
THE MID TO LATE WEEK. CONSEQUENTLY, A GALE WATCH HAS BEEN ISSUED
FOR ALL OF THE ATLANTIC FORECAST ZONES STARTING TUESDAY EVENING,
AND FOR THE DELAWARE BAY STARTING WEDNESDAY MORNING. THE WATCH
CURRENTLY GOES THROUGH THE DAY ON THURSDAY, WHEN WE HAVE THE
MOST CONFIDENCE IN GALE CONDITIONS.
GALE CONDITIONS MAY LINGER INTO FRIDAY AND SATURDAY DEPENDING ON
THE EVOLUTION OF THE COASTAL LOW, WHICH IS UNCERTAIN IN THIS
TIME FRAME.
RIP CURRENTS...
MONDAY... THERE IS A MODERATE RISK FOR DANGEROUS RIP CURRENTS
TODAY THANKS TO THE ONSHORE COMPONENT OF THE PERSISTENT
NORTHEASTERLY WINDS. BREAKING WAVES IN THE SURF ZONE WILL BE
AROUND 2 TO 4 FEET.
TUESDAY...NORTHEASTERLY WINDS STRENGTHEN TO 20 TO 30 MPH WITH
WAVE HEIGHTS IN THE SURF ZONE BUILDING TO 3 TO 5 FEET. AS A
RESULT, THERE IS A HIGH RISK OF RIP CURRENTS BOTH FOR THE NEW
JERSEY SHORE AND THE DELAWARE BEACHES.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...COASTAL FLOOD ADVISORY FROM 4 PM TO 10 PM EDT TUESDAY FOR
NJZ020-022>027.
COASTAL FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT FOR NJZ020-022>027.
HIGH RISK FOR RIP CURRENTS FROM TUESDAY MORNING THROUGH TUESDAY
EVENING FOR NJZ014-024>026.
DE...COASTAL FLOOD ADVISORY FROM 4 PM TO 10 PM EDT TUESDAY FOR
DEZ002>004.
COASTAL FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT FOR DEZ002>004.
HIGH RISK FOR RIP CURRENTS FROM TUESDAY MORNING THROUGH TUESDAY
EVENING FOR DEZ004.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TUESDAY TO 6 AM EDT WEDNESDAY
FOR ANZ430-431.
GALE WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY AFTERNOON
FOR ANZ430-431.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ450>455.
GALE WATCH FROM TUESDAY EVENING THROUGH THURSDAY AFTERNOON FOR
ANZ450>455-480>483-485.
DISCUSSION...COOPER/HOEFLICH/WFO PHI
AVIATION...AKL/COOPER/FITZSIMMONS/WFO PHI
MARINE...AKL/COOPER/FITZSIMMONS/WFO PHI
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