805
FXUS61 KPHI 012328
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
728 PM EDT SAT AUG 1 2026
WHAT HAS CHANGED
AVIATION SECTION UPDATED FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
1. TRANQUIL WEATHER CONTINUES TODAY, THOUGH A FEW VERY ISOLATED
INSTABILITY/SEA BREEZE SHOWERS WILL OCCUR THIS AFTERNOON.
2. SHOWERS AND THUNDERSTORMS INCREASE IN COVERAGE SUNDAY NIGHT INTO
MONDAY WITH THE POTENTIAL FOR AREAS OF HEAVY RAIN LEADING TO A RISK
OF FLASH FLOODING. THERE IS ALSO SOME RISK FOR STRONG TO SEVERE
THUNDERSTORMS.
DISCUSSION
KEY MESSAGE 1...TRANQUIL WEATHER CONTINUES TODAY, THOUGH A FEW
VERY ISOLATED INSTABILITY/SEA BREEZE SHOWERS WILL OCCUR THIS
AFTERNOON.
SURFACE HIGH PRESSURE RIDGES ACROSS THE AREA BEGINS SLOWLY
MOVING OFFSHORE TONIGHT. THE HIGH IS RELATIVELY WEAK AND WITH
THE WARM AND RELATIVELY HUMID AIRMASS, THERE COULD BE A FEW
POP- UP SHOWERS ACROSS THE SEA- BREEZE FRONTS THRU THE REST OF
THE AFTERNOON. COVERAGE ON FRIDAY WAS RATHER SPARSE, AND IT
APPEARS IT WILL BE THAT WAY AGAIN TODAY. CLOUDS AND SOUTHERLY
FLOW TONIGHT WILL PROMOTE A MILDER NIGHT, WITH LOWS MAINLY IN
THE UPPER 60S TO LOWER 70S. SUNDAY WILL BE NOTABLY MORE HUMID,
WITH MOST AREAS SEEING DEW POINTS CREEP BACK INTO THE LOW-MID
70S AND ACTUAL TEMPS AGAIN IN THE MID-UPPER 80S. THIS WILL
RESULT IN A DAY THAT FEELS WARMER DESPITE RELATIVELY MINIMAL
SUNSHINE UNDER THICKENING HIGH AND MID CLOUDS. THE NEXT SYSTEM
APPROACHING MAY BRING SOME SHOWERS AND STORMS INTO THE AREA
LATE, BUT MOST LIKELY HOLD OFF UNTIL EVENING, SO HAVE GENERALLY
HELD POPS BELOW LIKELY.
KEY MESSAGE 2...SHOWERS AND THUNDERSTORMS INCREASE IN COVERAGE
SUNDAY NIGHT INTO MONDAY WITH THE POTENTIAL FOR AREAS OF HEAVY RAIN
LEADING TO A RISK OF FLASH FLOODING. THERE IS ALSO SOME RISK FOR
STRONG TO SEVERE THUNDERSTORMS.
AN UPPER-LEVEL TROUGH WILL SHIFT ACROSS EASTERN CANADA INTO EARLY
NEXT WEEK. WHILE THIS OCCURS, STRONG ENERGY CRESTS A RIDGE IN THE
WEST AND THIS CARVES THE TROUGH OUT MORE INTO THE TENNESSEE AND OHIO
VALLEYS BY LATER THIS WEEKEND. THERE CONTINUES TO BE SIGNALS IN
MODEL GUIDANCE SHOWING THIS TROUGH POTENTIALLY BECOMING CLOSED
OFF INTO EARLY NEXT WEEK AS IT GRADUALLY APPROACHES THE EAST.
THE MAIN TROUGH MAY DETACH AND DEPART TO THE NORTHEAST LEAVING
BEHIND A LINGERING CLOSED LOW. THIS SCENARIO WOULD LEAD TO THE
SYSTEM SLOWING ITS EASTWARD PROGRESSION THROUGH THE FIRST HALF
OF NEXT WEEK. THE MODEL TRENDS CONTINUE TO SHOW A SLOWER ARRIVAL
OF THIS SYSTEM, WITH THE BULK OF THE SHOWERS AND THUNDERSTORMS
OCCURRING LATER SUNDAY NIGHT AND ESPECIALLY ON MONDAY.
AHEAD OF THE STRENGTHENING UPPER-LEVEL TROUGH, DEEP SOUTH TO
SOUTHWEST FLOW WILL INCREASE AND THIS WILL RAMP UP THE LOW-LEVEL
MOISTURE AND TEMPERATURE ADVECTION. IT WILL THEREFORE BE A HUMID
TIME FRAME AS THE PRECIPITABLE WATERS SURGE TO 2+ INCHES. THERE
LOOKS TO BE MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS, STARTING
WITH AN INITIAL ROUND LATE SUNDAY NIGHT INTO MONDAY WITH THE
INCREASED WARM AIR ADVECTION REGIME. INSTABILITY WILL INCREASE,
HOWEVER THE TIMING AT NIGHT SHOULD LIMIT THE THUNDERSTORM INTENSITY
ESPECIALLY SINCE IT MAY BE MORE OF ELEVATED CONVECTION INITIALLY.
AREAS OF HEAVY RAIN HOWEVER WILL BE PROBABLE GIVEN THE INCREASING
FORCING FOR ASCENT AND HIGH WATER CONTENT AIR. WHEN LOOKING AT MODEL
SOUNDINGS, THE HIGH PRECIPITABLE WATER VALUES, WARM CLOUD LAYER
PROCESSES, AND TALL SKINNY CAPE PROFILES SHOW THE HEAVY RAIN
POTENTIAL. FOR SUNDAY NIGHT INTO MONDAY, THE WEATHER PREDICTION
CENTER HAS US IN A MARGINAL RISK (LEVEL 1 OUT OF 4) FOR
EXCESSIVE RAINFALL.
ON MONDAY, RIPPLES OF ENERGY ALONG THE INCOMING COLD FRONT
DURING THE DAY MAY ENHANCE THE CONVECTIVE POTENTIAL AND WITH DEEP
SOUTHERLY FLOW, SOME TRAINING CONVECTION WILL BE POSSIBLE. EXCESSIVE
RAINFALL RATES WOULD ENHANCE THE FLASH FLOODING RISK, ESPECIALLY
FROM THE I-95 CORRIDOR TO THE NORTH AND WEST WHERE THE ELEVATION
RISE COULD BOOST THE ASCENT SOME GIVEN A SOUTHEAST TO SOUTH LOW-
LEVEL FLOW. THERE IS A SLIGHT RISK (LEVEL 2 OUT OF 4) FOR EXCESSIVE
RAINFALL FOR MONDAY INTO MONDAY NIGHT FOR MAINLY NORTHERN PORTIONS
OF NEW JERSEY. THERE IS A MARGINAL RISK (LEVEL 1 OUT OF 4) FOR THE
REST OF OUR AREA.
IN TERMS OF THE SEVERE WEATHER RISK, UNCERTAINTY REMAINS AROUND THE
EXACT EXTENT OF INSTABILITY PRESENT DUE TO CLOUD COVER AND THE ROUND
OF SHOWERS/THUNDERSTORMS MONDAY MORNING. IF ENOUGH HEATING DEVELOPS
DURING THE COURSE OF MONDAY, THEN THIS COMBINED WITH SOME INCREASE
IN SHEAR (SOME INITIALLY BACKED LOW- LEVEL FLOW) COULD LEAD TO AT
LEAST SOME SEVERE THUNDERSTORM RISK. THE STORM PREDICTION CENTER HAS
HIGHLIGHTED AREAS NEAR AND NORTH OF PHILADELPHIA IN A MARGINAL RISK
(LEVEL 1 OUT OF 5) FOR ISOLATED SEVERE THUNDERSTORMS WITH THE
PRIMARY RISK BEING DAMAGING WIND GUSTS.
BEYOND MONDAY NIGHT, THE SLOW EASTWARD PROGRESSION OF THIS SYSTEM
LOOKS TO KEEP THE CHANCE FOR CONVECTION GOING FOR MULTIPLE DAYS NEXT
WEEK AS THE COLD FRONT MAY STALL IN OUR VICINITY. THE CURRENT
FORECAST DOES HAVE SHOWER AND THUNDERSTORM CHANCES EACH DAY NEXT
WEEK, MAINLY IN THE AFTERNOON AND EVENING. THE MOST ACTIVE DAY, AS
OF NOW, HOWEVER LOOKS TO BE MONDAY GIVEN THE OVERLAP OF FAVORABLE
PARAMETERS FOR MORE WIDESPREAD CONVECTIVE DEVELOPMENT.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR WITH GRADUALLY LOWERING CEILINGS. SOUTHEAST WINDS
5-10 KTS. HIGH CONFIDENCE.
SUNDAY...VFR TO START. CEILINGS WILL CONTINUE TO GRADUALLY
LOWER, WITH MVFR CEILINGS EXPECTED FIRST AT RDG AND ABE AFTER
19-20Z AND THEN SPREADING EAST TOWARDS 00Z. SCATTERED SHOWERS
AND STORMS ARE ALSO POSSIBLE AFTER 18-19Z, WITH RESTRICTIONS
POSSIBLE IN ANY HEAVIER SHOWER OR STORM. MORE WIDESPREAD
ACTIVITY IS EXPECTED TO HOLD OFF UNTIL AFTER 00Z. WINDS
GENERALLY SOUTHEAST, INCREASING TO 10-15 KT WITH GUSTS NEAR 20
KT IN THE AFTERNOON. MODERATE CONFIDENCE OVERALL.
OUTLOOK...
SUNDAY NIGHT AND MONDAY...PERIODS OF SUB-VFR CONDITIONS ALONG WITH
SHOWERS AND THUNDERSTORMS.
TUESDAY THROUGH THURSDAY...TIMES OF SUB-VFR CONDITIONS ARE PROBABLE
AS SOME SHOWERS AND THUNDERSTORMS CONTINUE, ESPECIALLY EACH
AFTERNOON AND EVENING.
MARINE
NO MARINE HEADLINES EXPECTED THROUGH SUNDAY. SOUTHERLY WINDS
AROUND 10-15 KT WITH A FEW GUSTS UP TO 20 KTS. SEAS 2 TO 3
FEET.
OUTLOOK...
SUNDAY NIGHT AND MONDAY...A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR
ALL OF THE NEARSHORE ATLANTIC COASTAL WATERS FROM MIDNIGHT SUNDAY
NIGHT TO MIDNIGHT MONDAY NIGHT. A SOUTH TO SOUTH-SOUTHWEST FLOW
INCREASES SUNDAY NIGHT INTO MONDAY WITH WIND GUSTS UP TO 25 KT.
SEAS ALSO INCREASE TO 4-6 FEET. SOME GUSTY THUNDERSTORMS
POSSIBLE ON MONDAY.
TUESDAY THROUGH THURSDAY...NO MARINE HEADLINES ARE ANTICIPATED.
RIP CURRENTS...
FOR SUNDAY, WINDS TURN MORE SOUTHEASTERLY, WHICH IS MORE
DIRECTLY ONSHORE, AND INCREASING TO AROUND 15 MPH. WHILE THERE
WILL BE A SHORT 6-7 SECOND PERIOD SWELL, GIVEN THE STRONG WINDS, WAVE
HEIGHTS IN THE SURF ZONE MAY BE UP TO 3 FEET, PARTICULARLY AT
SOUTHEASTERLY FACING BEACHES. AS A RESULT, THERE IS A MODERATE
RISK FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS FOR THE
BEACHES OF CAPE MAY, ATLANTIC, AND OCEAN COUNTIES OF NJ. AT THE
BEACHES OF MONMOUTH COUNTY, NJ AS WELL AS THE DELAWARE BEACHES,
THE RISK FOR SUNDAY REMAINS LOW GIVEN THAT WINDS AT THESE
BEACHES WILL BE MORE SHORE PARALLEL.
FOR MONDAY, THE RISK FOR THE DEVELOPMENT OF RIP CURRENTS
INCREASES TO MODERATE FOR ALL BEACHES. WINDS WILL BE MORE SHORE
PARALLEL OUT OF THE SOUTH-SOUTHWEST BUT INCREASING TO AROUND
15-20 MPH. ADDITIONALLY, A STRENGTHENING SWELL WILL RESULT IN
OFFSHORE SEAS OF 5-6 FEET. IN THE SURF ZONE, THIS TRANSLATES TO
BREAKING WAVES OF 2-3 FEET WITH A MEDIUM 8-9 SECOND PERIOD.
FOR SPECIFIC BEACH FORECASTS, VISIT WEATHER.GOV/BEACH/PHI
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT SUNDAY NIGHT TO MIDNIGHT
EDT MONDAY NIGHT FOR ANZ450>455.
DISCUSSION...GORSE/GUZZO/OHARA/RCM
AVIATION...COOPER/GUZZO/OHARA/RCM
MARINE...AKL/GUZZO/RCM
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