014
FXUS61 KPHI 110828
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
428 AM EDT SUN OCT 11 2026
WHAT HAS CHANGED
EXTENDED SMALL CRAFT ADVISORIES FOR THE COASTAL WATERS THROUGH
MONDAY NIGHT.
UPDATED THE AVIATION SECTION WITH THE 06Z TAFS.
KEY MESSAGES
1. THE REMNANTS OF ISAIAS SUNDAY AND SUNDAY NIGHT BRINGS RAIN, SOME
POTENTIALLY HEAVY AT TIMES, GUSTY WINDS AND A LOW RISK FOR AN
ISOLATED SEVERE THUNDERSTORM.
2. MINOR TIDAL FLOODING POSSIBLE WITH SUNDAY MORNING'S HIGH
TIDE, MAINLY FOR COASTAL AREAS WITHIN DELAWARE BAY. A COASTAL
FLOOD ADVISORY IS IN EFFECT FOR KENT COUNTY, DE.
DISCUSSION
KEY MESSAGE 1...THE REMNANTS OF ISAIAS SUNDAY AND SUNDAY NIGHT
BRINGS RAIN, SOME POTENTIALLY HEAVY AT TIMES, GUSTY WINDS AND A LOW
RISK FOR AN ISOLATED SEVERE THUNDERSTORM.
A CLOSED MID LEVEL LOW AND SURFACE LOW, THE REMNANTS OF FORMER
HURRICANE ISAIAS, IS FORECAST TO SLIDE ACROSS THE MID-ATLANTIC
REGION SUNDAY NIGHT INTO EARLY MONDAY MORNING. AS THIS OCCURS, IT IS
FORECAST TO WEAKEN FURTHER WITH THE CLOSED MID LEVEL LOW OPENING UP
MORE INTO A TROUGH. THE MAIN IMPACTS FOR OUR AREA WILL BE WIDESPREAD
RAINFALL AND SOME GUSTY WINDS. AN EAST TO SOUTHEAST ROBUST LOW-
LEVEL JET (AROUND 925 MB) ON THE ORDER OF 40-60 KNOTS WILL
OVERSPREAD OUR AREA SUNDAY MORNING AND THIS WILL RAPIDLY INCREASE
THE WARM AIR ADVECTION AND MOISTURE ADVECTION ACROSS THE REGION.
PWAT VALUES ARE EXPECTED TO SURGE INTO THE 1.75 TO 2.25 INCH
RANGE. AS THIS COINCIDES WITH STRONG FORCING FOR ASCENT SUNDAY,
SOME PERIODS OF HEAVIER RAIN SHOULD OCCUR. TOTAL RAINFALL
AMOUNTS STILL LOOK TO BE 1-2 INCHES ACROSS THE ENTIRE AREA,
HOWEVER UP TO 3 INCHES WILL BE POSSIBLE WHERE SOME ENHANCEMENT
AND/OR EMBEDDED CONVECTIVE ELEMENTS OCCUR. THIS EVENT SHOULD
INITIALLY BE IN THE FORM OF STRATIFORM RAIN BEFORE TRANSITIONING
TO MORE CONVECTIVE/SHOWERY SUNDAY NIGHT INTO EARLY MONDAY
MORNING. WPC HAS MAINTAINED MOST OF THE REGION IN A MARGINAL
RISK (LEVEL 1 OUT OF 4) FOR EXCESSIVE RAINFALL FOR SUNDAY INTO
SUNDAY NIGHT, WHICH MEANS ISOLATED INSTANCES OF FLASH FLOODING
WILL BE POSSIBLE. THERE ARE CURRENTLY NO RIVER GAUGES FORECAST
TO REACH MINOR FLOOD STAGE, HOWEVER IF EVEN HEAVIER RAIN OCCURS
INTO NORTHERN NJ (ESPECIALLY 2.5+ INCHES), THIS COULD CAUSE SOME
GAUGES IN THE RARITAN BASIN (THE MILLSTONE RIVER) TO RISE TO
MINOR FLOOD STAGE. IF RAINFALL RATES BECOME HIGH ENOUGH FOR A
TIME, THEN SOME URBAN/ROADWAY FLOODING WILL ALSO BE POSSIBLE.
AS THE LOW-LEVEL JET MOVES ACROSS THE AREA AND THE WARM SECTOR
GRADUALLY SPREADS NORTHWARD ON SUNDAY, AN EASTERLY WIND WILL
INCREASE AND BECOME GUSTY. WIND GUSTS UP TO 30 MPH ARE
ANTICIPATED INLAND WITH GUSTS UP TO 40 MPH ALONG THE COAST. THE
WINDS SHOULD DIMINISH SUNDAY NIGHT AS THE REMNANT SURFACE LOW
SLIDES ACROSS OUR AREA AND THE LOW-LEVEL JET SHIFTS AWAY FROM
OUR REGION.
WHILE THIS IS THE REMNANTS OF A TROPICAL SYSTEM, IT HAS HAD PLENTY
OF TIME BEING A POST-TROPICAL SYSTEM PRIOR TO REACH OUR AREA.
NEVERTHELESS, LOW-LEVEL SHEAR PROFILES INCREASE QUITE A BIT FOR A
TIME SUNDAY AFTERNOON INTO SUNDAY EVENING AS THE MAIN RAIN
SHIELD STARTS TO SHIFT NORTH AND EAST OF OUR AREA. DURING THIS
TIME, SOME INSTABILITY MAY TRY TO ADVECT NORTHWARD ACROSS
DELMARVA INTO SOUTHERN NEW JERSEY ESPECIALLY, BUT THE WINDOW OF
OPPORTUNITY IS RATHER SMALL WHERE LINGERING STRONGER DEEP-
LAYER SHEAR OVERLAPS WITH SOME INCREASE IN INSTABILITY. PERHAPS
A FEW TRANSIENT LOW-TOPPED SUPERCELLS WITH AN ISOLATED DAMAGING
WIND GUST ARE POSSIBLE AS A RESULT, BUT CONFIDENCE REMAINS LOW.
THE SEVERE SCENARIO, HOWEVER, IS HIGHLY CONTINGENT ON HOW MUCH
HIGHER DEW POINTS ADVECT NORTHWARD WITH ENOUGH LOW- LEVEL
INSTABILITY, AND THIS LOOKS TO BE GREATER TO OUR SOUTH AND
SOUTHWEST. THE RISK FOR A WEAK/BRIEF TORNADO IN OUR AREA REMAINS
VERY LOW.
SOME SHOWERS LINGER EARLY MONDAY MORNING, ESPECIALLY FROM ABOUT THE
I-95 CORRIDOR ON SOUTH AND EAST, THEN DRYING SHOULD QUICKLY OCCUR
DURING MONDAY AS A NORTH TO NORTHWEST WIND INCREASES FOR A TIME AND
THE ENTIRE WEAKENING SYSTEM EXITS TO OUR EAST AND NORTHEAST.
KEY MESSAGE 2...MINOR TIDAL FLOODING POSSIBLE WITH SUNDAY MORNING'S
HIGH TIDE, MAINLY FOR COASTAL AREAS WITHIN DELAWARE BAY. A COASTAL
FLOOD ADVISORY IS IN EFFECT FOR KENT COUNTY, DE.
WITH A PERIOD OF EAST/SOUTHEASTERLY FLOW EXPECTED AND THE
UPCOMING NEW MOON, INCREASED TIDAL LEVELS ARE EXPECTED LATER
THIS WEEKEND. THIS WILL RESULT IN SPOTTY TO WIDESPREAD MINOR
TIDAL FLOODING, MAINLY FOR COASTAL COMMUNITIES ALONG DELAWARE
BAY. THE ONLY FORECAST POINT CURRENTLY FORECAST TO REACH
WIDESPREAD MINOR IS BOWERS BEACH. AS A RESULT, WENT AHEAD AN
ISSUED A COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM FOR KENT
COUNTY, DE. AN ADDITIONAL ROUND OF COASTAL FLOOD ADVISORIES MAY
BE NEEDED FOR SOME DELWARE BAY COMMUNITIES FOR THE MONDAY
MORNING HIGH TIDE.
THIS WON'T BE A SIGNIFICANT EVENT FOR THE ATLANTIC OCEAN COASTLINE,
WHERE ONLY SPOTTY MINOR TIDAL FLOODING IS EXPECTED FROM
BARNEGAT BAY ON SOUTH. THIS INCLUDES THE DELAWARE BEACHES AND
BACK BAY COMMUNITIES IN SUSSEX COUNTY, DE.
OVERALL, THIS EVENT WILL BE NOTHING LIKE LATE SEPTEMBER.
THE CURRENT FORECAST HAS NO TIDAL FLOODING FOR AREAS ALONG THE
ATLANTIC COASTLINE NORTH OF BARNEGAT BAY. THE FORECAST FOR THE
TIDAL DELAWARE RIVER AND CHESAPEAKE BAY ALSO HAS TIDE LEVELS
STAYING BELOW FLOOD STAGE AT THIS TIME.
AVIATION /07Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TONIGHT...VFR. CEILINGS LOWER EARLY THIS MORNING. WINDS
REMAIN OUT OF THE EAST AT 5-10 KTS. GUSTS OF 15-20 KTS DEVELOP
AT KMIV AND KACY AFTER 08Z. HIGH CONFIDENCE.
SUNDAY...MVFR CONDITIONS DEVELOP AROUND DAYBREAK AND QUICKLY
DROP TO IFR TOWARDS MID-MORNING DUE TO LOWERING CEILINGS.
WIDESPREAD RAIN MOVES IN AROUND DAYBREAK AND CONTINUES THROUGH
THE DAY WITH VISIBILITY RESTRICTIONS. PERIODS OF LIFR CONDITIONS
POSSIBLE. POCKETS OF MODERATE TO HEAVY RAIN AT TIMES WITH VCTS
LATE AFTERNOON. WINDS ALSO REMAIN OUT OF THE EAST BUT INCREASE
TO 10-15 KT WITH GUSTS TO 20-25 KT. A FEW GUSTS UP TO 30 KTS
POSSIBLE AT KMIV AND KACY. MODERATE CONFIDENCE.
SUNDAY NIGHT...SUB-VFR CONDITIONS PREVAIL. RAIN BECOMES MORE
SCATTERED OVERNIGHT WITH VCTS. VIS RESTRICTIONS MAY EASE TO
MVFR, BUT IFR/LIFR CEILINGS REMAIN. WINDS GRADUALLY BACK TO THE
NNE AND EASE TO AROUND 10 KTS. MODERATE CONFIDENCE IN LOW
CEILINGS, BUT LOW CONFIDENCE OVERALL.
OUTLOOK...
MONDAY...SUB-VFR POSSIBLE IN THE MORNING DUE TO LOW CLOUDS.
CONDITIONS GRADUALLY TREND TOWARDS VFR THROUGHOUT THE DAY.
MONDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. NO SIGNIFICANT
WEATHER.
WEDNESDAY...VFR. GUSTY WNW WINDS POSSIBLE.
THURSDAY...VFR. NO SIGNIFICANT WEATHER.
MARINE
SMALL CRAFT ADVISORIES FOR THE COASTAL OCEAN WATERS WERE
EXTENDED INTO MONDAY NIGHT.
FOR SUNDAY, EASTERLY WINDS INCREASE FURTHER
TO 30 KTS WITH OCCASIONAL GUSTS UPWARDS OF 35 KTS, PARTICULARLY
SUNDAY MORNING. SEAS CONTINUE TO BUILD TO 7-10 FEET BY SUNDAY
AFTERNOON. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE DELAWARE
BAY AND ALL OF THE ATLANTIC COASTAL WATERS FROM EARLY SUNDAY
MORNING INTO SUNDAY NIGHT. DUE TO THE OCCASIONAL NATURE OF GALE
FORCE GUSTS, THE GALE WATCH HAS BEEN CANCELLED FOR THE OFFSHORE
WATERS. VISIBILITY RESTRICTIONS ARE LIKELY IN RAIN WHICH COULD
BE MODERATE TO HEAVY AT TIMES.
WINDS SHIFT MORE SOUTHERLY AND DIMINISH BELOW ADVISORY CRITERIA AS
THE LOW CENTER MOVES ACROSS THE WATERS OVERNIGHT BEFORE
SHIFTING MORE NORTHERLY AS THE LOW BEGINS TO DEPART EARLY MONDAY
MORNING. SEAS WILL BE SLOW TO SUBSIDE, STAYING ELEVATED AROUND
6-8 FEET.
OUTLOOK...
MONDAY...SCA CONDITIONS FOR THE COASTAL OCEAN WATERS DUE TO
LINGERING SEAS OF 6-8 FEET AND NORTHERLY WIND GUSTS UPWARDS OF
25 KTS THAT GRADUALLY DIMINISH INTO MONDAY NIGHT.
TUESDAY THROUGH THURSDAY...NO MARINE HAZARDS EXPECTED.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EDT THIS
AFTERNOON FOR DEZ002.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ430-
431.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 4 AM EDT
TUESDAY FOR ANZ450.
SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 4 AM EDT
TUESDAY FOR ANZ451-452.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ453>455.
DISCUSSION...MJL/WFO PHI
AVIATION...MJL
MARINE...MJL
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