165
FXUS61 KPHI 030543
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
143 AM EDT MON AUG 3 2026
WHAT HAS CHANGED
UPDATED AVIATION SECTION FOR 06Z TAFS.
KEY MESSAGES
1. SHOWERS AND THUNDERSTORMS INCREASE IN COVERAGE TONIGHT 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.
2. A WARM FRONT IS EXPECTED TO LIFT THROUGH THE REGION TUESDAY NIGHT
INTO WEDNESDAY, BRINGING THE NEXT CHANCE FOR SHOWERS AND STORMS.
3. FOR THE LATER HALF OF THE WEEK, WE WILL HAVE A WARM, HUMID, AND
AT TIMES STORMY PATTERN IN PLACE.
DISCUSSION
KEY MESSAGE 1...SHOWERS AND THUNDERSTORMS INCREASE IN COVERAGE
TONIGHT 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 IS MOVING INTO THE NORTHEAST THROUGH
MONDAY. AS THIS TROUGH MOVES INTO THE NORTHEAST, THERE WILL BE
PLENTY OF UPPER-LEVEL ENERGY MOVING THROUGH THE REGION. THERE IS
ALSO A WARM AIR ADVECTION SET UP INTO TONIGHT. FOR MONDAY,
THERE WILL BE A JET STREAK OVERHEAD WITH OUR LOCATION IN THE
RIGHT ENTRANCE REGION. ALL OF THESE FACTORS WILL LEAD TO A
PERIOD OF UNSETTLED WEATHER IN THE NEAR TERM.
AS WE HEAD INTO TONIGHT, AN INCREASING SOUTH TO SOUTHWEST FLOW WILL
CONTINUE TO BRING IN INCREASING MOISTURE WITH PWAT VALUES TONIGHT
SURGING TO 2+ INCHES TONIGHT. THE COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL ALSO BE INCREASING WITH THE WARM AIR
ADVECTION REGIME ALLOWING FOR AN INCREASE IN ASCENT. OVERNIGHT,
INSTABILITY WILL ALSO BE INCREASING, BUT THE TIMING IS NOT VERY
SUPPORTIVE OF SEVERE WEATHER. THROUGH TONIGHT, THERE IS A
MARGINAL (LEVEL 1 OUT OF 4) RISK FOR EXCESSIVE RAINFALL. MODEL
SOUNDINGS CONTINUE TO SHOW THIS RISK INTO TONIGHT AS WELL WITH
THE HIGH PWATS AND WARM CLOUD LAYER PROCESSES.
ON MONDAY, A COLD FRONT WILL BE APPROACHING THE REGION. THERE
CONTINUES TO BE A SIGNAL FOR RIPPLES OF ENERGY ALONG THE FRONT.
ALSO, IN THE UPPER-LEVELS, A JET STREAK WILL BE OVERHEAD WITH OUR
AREA IN THE RIGHT ENTRANCE REGION WHICH ALLOWS FOR ADDITIONAL
FORCING AND ASCENT FOR OUR AREA. SHOWERS AND THUNDERSTORMS LOOK TO
BE ONGOING INTO TOMORROW MORNING WITH AN INCREASE IN THE COVERAGE
AGAIN DURING THE AFTERNOON AND EVENING.
AS PWATS CONTINUE TO REMAIN ABOVE 2 INCHES AHEAD OF THE FRONT, THE
RISK FOR HEAVY RAIN CONTINUES. THE OVERALL FLOW WILL BE WEAKER
TOMORROW WITH TRAINING AND SLOW MOVING STORMS BEING A CONCERN
LEADING TO THE HEAVY RAINFALL RISK. THERE IS A SLIGHT (LEVEL 2 OUT
OF 4) FOR EXCESSIVE RAINFALL FOR TOMORROW FOR AREAS NEAR AND EAST
OF THE I-95 CORRIDOR. THE REMAINDER OF THE AREA IS IN A MARINGAL
(LEVEL 1 OUT OF 4) RISK FOR EXCESSIVE RAINFALL. DUE TO THE RISK FOR
HEAVY RAINFALL TONIGHT AND INTO TOMORROW, A FLOOD WATCH HAS BEEN
ISSUED FOR THE I-95 CORRIDOR, NORTHERN NJ, AND THE LEHIGH VALLEY FOR
THE POTENTIAL OF RAINFALL RATES OF 1-3 INCHES PER HOUR. RAINFALL
AMOUNTS OF 1-2 INCHES ARE POSSIBLE WITH LOCALIZED AMOUNTS TO 3-5
INCHES. THIS FLOOD WATCH IS IN EFFECT FROM 8 PM THIS EVENING UNTIL
11 PM MONDAY.
IN TERMS OF THE SEVERE WEATHER RISK TOMORROW, UNCERTAINTY REMAINS
AROUND THE EXACT EXTENT OF INSTABILITY PRESENT DUE TO CLOUD COVER
AND THE ROUND OF SHOWERS/THUNDERSTORMS AROUND TOMORROW MORNING. IF
ENOUGH HEATING DEVELOPS DURING THE COURSE OF THE DAY, THEN THIS
COMBINED WITH SOME INCREASE IN SHEAR AHEAD OF THE FRONT COULD LEAD
TO AT LEAST SOME SEVERE THUNDERSTORM RISK. THE STORM PREDICTION
CENTER HAS HIGHLIGHTED AREAS NEAR AND NORTHWEST OF THE I-95 CORRIDOR
IN A MARGINAL RISK (LEVEL 1 OUT OF 5) FOR ISOLATED SEVERE
THUNDERSTORMS WITH THE PRIMARY RISK BEING DAMAGING WIND GUSTS.
KEY MESSAGE 2...A WARM FRONT IS EXPECTED TO LIFT THROUGH THE REGION
TUESDAY NIGHT INTO WEDNESDAY, BRINGING THE NEXT CHANCE FOR SHOWERS
AND STORMS.
ONCE THE CURRENT SYSTEM GETS EAST OF OUR REGION, THE NEXT THING TO
WATCH IS A WARM FRONT SLOWLY LIFTING NORTH OVER OUR REGION. THE MOST
LIKELY TIME PERIOD FOR THIS FRONTAL PASSAGE IS TUESDAY NIGHT INTO
WEDNESDAY, LEAVING THE DAY TIME ON TUESDAY RELATIVELY DRY. HOWEVER,
AT LEAST ONE MODEL IS SHOWING A VERY FAST WARM FRONTAL PASSAGE WITH
THE FRONT NORTH OF OUR REGION BY LATE WEDNESDAY NIGHT. IN THIS FAST
SOLUTION, THE PATTERN IS ODD, DEPICTING A VERY PRONOUNCED MID AND
UPPER LEVEL SHORT WAVE RIDGE IN PLACE THROUGHOUT THE DAY. THIS
PATTERN ISN'T FAVORABLE FOR FAST FRONTAL PASSAGES. THEREFORE, HAVE
FAVORED THE BLEND OF GUIDANCE, WHICH FAVORS THE SLOWER SOLUTION.
AS FAR AS HAZARDS, THE PRIMARY HAZARD IS LIKELY TO BE HEAVY RAIN
LEADING TO FLASH FLOODING. THERE WILL LIKELY BE SIGNIFICANT LOW
LEVEL MOISTURE ADVECTION BEHIND THE FRONT, INCREASING THE RISK FOR
HEAVY RAIN. THAT COMBINED WITH THE FACT THAT STORM MOTIONS ARE
LIKELY TO BE QUITE SLOW (LESS THAN 20 MPH), INCREASES THE RISK FOR
FLASH FLOODING. ONE FACTOR WHICH WE WON'T KNOW UNTIL LATE MONDAY IS
HOW MUCH ANTECEDENT CONDITIONS WILL PLAY A ROLE IN THE FLASH
FLOODING THREAT - AREAS THAT GET HEAVY RAIN THROUGH THE DAY ON
MONDAY WILL HAVE LITTLE OPPORTUNITY FOR THE WATER TO DRAIN BEFORE
THIS NEXT ROUND OF RAIN CHANCES.
THE SEVERE THREAT IS LESS CLEAR. THIS WILL BE DEPENDENT ON THE
TIMING OF THE FRONT - IF THE FRONTAL PASSAGE, AND THUS PRIME PERIOD
FOR ANY SHOWERS AND STORMS IS DURING THE DAYLIGHT HOURS WHEN
INSTABILITY IS MAXIMIZED, THERE WILL BE SOME THREAT FOR DAMAGING
WINDS. SOME MODEL SOUNDINGS SHOW A VERY DRY MID LAYER, INCREASING
THE THREAT FOR DOWNBURSTS.
KEY MESSAGE 3...FOR THE LATER HALF OF THE WEEK, WE WILL HAVE A WARM,
HUMID, AND AT TIMES STORMY PATTERN IN PLACE.
ONCE THE MID WEEK WARM FRONT MOVES NORTH OF OUR REGION, WE WILL
LIKELY BE SANDWICHED BETWEEN A BERMUDA CENTERED WELL TO OUR EAST,
AND A NEARLY STATIONARY MID LEVEL TROUGH AXIS CENTERED OVER THE
WESTERN GREAT LAKES REGION.
THE NET RESULT OF THIS IS THAT OUR REGION WILL HAVE WARM AND MOIST
SOUTHWESTERLY FLOW IN PLACE FOR MULTIPLE DAYS. AS SUCH, EXPECT HOT
AND HUMID CONDITIONS. ADDITIONALLY, THERE COULD BE DAILY RAIN
CHANCES, FROM TWO DIFFERENT SOURCES. FIRST, IF THERE IS ANY SHOWER
OR STORM DEVELOPMENT ON THE SEA BREEZE IN THE AFTERNOON. SECONDLY,
THERE COULD BE SOME EMBEDDED VERY SMALL SHORT WAVE TROUGHS THAT
PROPAGATE NORTHEASTWARD OVER OUR REGION DURING THIS TIME.
AVIATION /06Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
OVERNIGHT...LARGELY MVFR TO IFR BUT BRIEF PERIODS OF SUB-IFR
DURING THE MOST INTENSE SHOWERS/TSTMS. SHOWERS/TSTMS SEEM TO BE
REDEVELOPING ACROSS MOST OF DELMARVA/SOUTH NJ AND THESE SHOULD
MOVE NORTH AND AFFECT THE DELAWARE VALLEY TAF SITES THRU DAWN.
OTHERS WILL MOVE ACROSS KRDG/KABE. LIGHT SOUTH WINDS. LOW/MEDIUM
CONFID.
MONDAY...IFR TO MVFR. DURING THE MORNING, CEILINGS LOOK TO LIFT A
BIT TO MVFR. THERE IS VCSH AT THE LEHIGH VALLEY TERMINALS GIVEN
SHOWER COVERAGE. THE REMAINDER OF THE TERMINALS HAVE PREVAILING SHRA
AND SOME PROB30 GROUPS, MAINLY 18Z-21Z FOR POTENTIAL
THUNDERSTORMS. VISIBILITY RESTRICTIONS ARE ALSO EXPECTED WITH
ANY SHOWERS OR THUNDERSTORMS IMPACTING THE TERMINALS. LOW
CONFIDENCE FOR THE CONVECTION WITH MEDIUM CONFIDENCE ON THE
CEILING RESTRICTIONS.
OUTLOOK...
MONDAY NIGHT AND TUESDAY...PREVAILING VFR. SOME LINGERING SHOWERS
AND STORMS MONDAY NIGHT MAY BRIEFLY LOWER CONDITIONS TO MVFR.
TUESDAY NIGHT THROUGH FRIDAY...PERIODS OF MVFR OR LOWER CONDITIONS
POSSIBLE, PRIMARILY IN THE AFTERNOON AND EVENING PERIODS EACH DAY,
DUE TO SHOWERS AND STORMS.
MARINE
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR ALL OF THE NEARSHORE
ATLANTIC COASTAL WATERS THROUGH 6 AM TUESDAY. SOUTH FLOW CONTINUES
TODAY WITH WIND GUSTS UP TO 30 KT. SEAS WILL BE MOSTLY 5 TO 8 FEET.
SCATTERED GUSTY THUNDERSTORMS ARE POSSIBLE TODAY, PARTICULARLY
IN THE AFTERNOON AND EVENING. A SLOW DECREASE WINDS WINDS AND
SEAS TONIGHT WITH SUB-SCA PROBABLE BY DAWN. FAIR OVERNIGHT.
OUTLOOK...
TUESDAY AND WEDNESDAY...WINDS AND SEAS SHOULD STAY BELOW SCA
CRITERIA.
THURSDAY AND FRIDAY...CURRENTLY FORECASTING WINDS AND SEAS TO STAY
BELOW SCA CRITERIA, BUT WIND GUSTS NEAR 25 KT ARE POSSIBLE BOTH
DAYS.
RIP CURRENTS...
THERE IS A HIGH RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS
ALONG THE NJ COAST ON TUESDAY DUE TO LONG PERIOD SWELLS WITH
SURF HEIGHTS NEAR OR ABOVE 3 FEET. FOR THE DELAWARE BEACHES,
THERE IS A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP
CURRENTS.
LOOKING AHEAD TO TUESDAY, SURF HEIGHTS SHOULD DECREASE, SO THE
RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS IS EXPECTED TO
BE MODERATE ALONG THE NJ COAST, AND LOW FOR THE DELAWARE
BEACHES.
PHI WATCHES/WARNINGS/ADVISORIES
PA...FLOOD WATCH THROUGH THIS EVENING FOR PAZ060>062-070-071-
101>106.
NJ...FLOOD WATCH THROUGH THIS EVENING FOR NJZ001-007>010-012>019.
HIGH RISK FOR RIP CURRENTS FROM 8 AM EDT THIS MORNING THROUGH THIS
EVENING FOR NJZ014-024>026.
DE...FLOOD WATCH THROUGH THIS EVENING FOR DEZ001.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ450>455.
DISCUSSION...AKL/GUZZO/JOHNSON
AVIATION...AKL/GUZZO/JOHNSON/PO
MARINE...GUZZO/JOHNSON/PO
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