434
FXUS61 KPHI 120655
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
255 AM EDT TUE AUG 12 2025
SYNOPSIS
HIGH PRESSURE WILL CONTINUE TO SHIFT TO OUR EAST TODAY. A SURFACE
TROUGH ACROSS OUR AREA WEDNESDAY GIVES WAY TO A COLD FRONT SETTLING
ACROSS OUR AREA FROM THE NORTHWEST DURING THURSDAY. THE FRONT MAY
STALL NEAR DELMARVA FRIDAY BEFORE DISSIPATING INTO SATURDAY. HIGH
PRESSURE ARRIVES FOR SATURDAY AND SUNDAY, THEN A COLD FRONT WILL
APPROACH FROM THE NORTHWEST ON MONDAY.
NEAR TERM /THROUGH TONIGHT/
WITH INCREASING LOW LEVEL MOISTURE OVER THE AREA, FOG AND STRATUS
WILL DEVELOP INTO DAYBREAK THIS MORNING. SOME FOG MAY BE LOCALLY
DENSE, BUT AT THIS TIME DOES NOT LOOK LIKE IT WARRANTS A DENSE FOG
ADVISORY. ANY FOG WILL LIFT AND DISSIPATE FROM 9 AM TO 10 AM THIS
MORNING.
BERMUDA HIGH PRESSURE SETS UP OFFSHORE. RETURN FLOW SETS UP, AND
TEMPERATURES AND DEW POINTS WILL INCREASE OVER THE AREA TODAY.
SURFACE DEW POINTS RISE INTO THE UPPER 60S AND LOW 70S, THOUGH THERE
SHOULD BE ENOUGH SUNSHINE DURING THE DAY FOR DEW POINTS TO MIX OUT
AND SHOULD BE A BIT LOWER THAN NBM GUIDANCE HAS TODAY. HIGHS TODAY
WILL BE IN THE UPPER 80S TO AROUND 90, AND MAX HEAT INDEX VALUES
WILL BE IN THE LOW 90S.
SOME SHORTWAVE ENERGY PASSING THROUGH THE REGION MAY SPARK OFF SOME
ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON, MAINLY OVER
SOUTHERN PORTIONS OF DELMARVA.
WARM AND MUGGY TONIGHT WITH INCREASING LOW LEVEL MOISTURE. PATCHY
FOG AND STRATUS WILL DEVELOP ONCE AGAIN. LOWS TONIGHT WILL BE IN THE
UPPER 60S TO LOW 70S.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
THIS WILL BE THE PERIOD OF GREATEST CHANCES FOR RAINS/TSTMS THIS
WEEK. LOW PRESSURE WELL TO THE NORTH (ACROSS CANADA) AND AN
UPPER TROUGH WILL CROSS THE REGION THRU THE PERIOD. IT WILL BE
OFFSHORE BY THURSDAY NIGH, WHEN POPS DECREASE BACK BELOW
CHANCE.
AS THE FRONT PASSES, SHOWERS/TSTMS BECOME LIKELY N/W WED THEN
CROSS THE REGION WEST TO EAST WED NIGHT. THE HEAT AND HIGHER DEW
POINTS WILL CREASE OPPORTUNITIES FOR LOCALLY HIGH RAINFALL
RATES. THE EXCESSIVE RAINFALL FORECAST FOR THE PERIOD IS CALLING
FOR A MARGINAL RISK. THE FRONT WASHES OUT ACROSS THE AREA
THURSDAY, SO TEMPS AND HUMIDITY WILL EXTEND INTO THURSDAY. POPS
WILL REMAIN MOSTLY IN THE CHANCE RANGE (30% TO 40%) BEFORE
LOWERING INTO THE SLIGHT CHANCE RANGE (10% TO 20%) THURSDAY
NIGHT.
TEMPERATURES WILL REMAIN HOT BUT NOT EXCESSIVELY SO. HIGHS WILL
BE IN THE UPPER 80S/LOW 90S WITH MUGGY CONDITIONS FORECAST. HEAT
INDEX VALUES WILL BE IN THE UPPER 90S. SO CAUTION IS ADVISED IF
OUTDOOR ACTIVITIES ARE GOING TO TAKE PLACE.
LONG TERM /FRIDAY THROUGH MONDAY/
SUMMER WEATHER CONTINUES DURING THE LONG TERM WITH TEMPERATURES AT
OR ABOVE NORMAL FOR THE WEEKEND AND INTO NEXT MONDAY. SUNDAY WILL
LIKELY BE THE WARMEST OF THE STRETCH WITH LOW/MID 90S MOST SPOTS
MID/UPPER 80S FOR THE SHORE AND FAR NW AREAS. THE UPPER RIDGING
WILL CONTINUE TO SUPPORT THE HOT TEMPS, BUT THERE ARE SIGNS
THAT NEXT WEEK THE RIDGE WILL RELAX, SO PERHAPS BACK TO NORMAL
(OR MAYBE A LITTLE BELOW) AFTER MONDAY. NORMAL HIGHS FOR THIS
TIME OF YEAR ARE IN THE MID/UPPER 80S FOR PHILADELPHIA/DELMARVA
AND SOUTH NJ AND UPPER 70S/LOW 80S FOR NW COUNTIES. NORMAL LOWS
ARE IN THE 60S MOST AREAS AND 57 FOR MOUNT POCONO.
NOT MUCH IN THE WAY OF RAINFALL FOR THE LONG TERM. POPS EACH DAY
WILL GENERALLY BE IN THE SLIGHT CHANCE RANGE (10% TO 20%). A
WEAK FRONT CROSSES THE AREA LATE SUNDAY/EARLY MONDAY AND CHANCE
PER THE NBM COULD REACH 25% FOR THE SOUTHERN POCONOS WITH THIS.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
EARLY THIS MORNING...CONDITIONS LOWER TO MVFR OR EVEN IFR IN FOG
AND STRATUS BY 09Z. VRB WINDS LESS THAN 3 KT TO NEARLY CALM
WINDS. LOW CONFIDENCE ON JUST HOW LOW CONDITIONS GET.
TODAY...VFR THROUGHOUT BY 15Z OR SO. S TO SW WINDS 5 TO 10 KT.
HIGH CONFIDENCE.
TONIGHT...LIGHT S TO SW WINDS. VFR INITIALLY, THEN FOG AND
STRATUS RESULT IN SUB-VFR CONDITIONS. LOW CONFIDENCE ON TIMING
AND HOW LOW CONDITIONS GET.
OUTLOOK...
WEDNESDAY THRU THURSDAY... VFR MUCH OF THE TIME, BUT SCATTERED
SHOWERS/TSTMS WILL CAUSE PERIODS OF LOWER CIGS/VSBYS.
THU NIGHT THRU SATURDAY... MOSTLY VFR. PATCHY MORNING FOG
POSSIBLE,
MARINE
SUB-SMALL CRAFT ADVISORY CONDITIONS TODAY AND TONIGHT. SOUTH TO
SOUTHWEST WINDS GENERALLY 10 TO 15 KT WITH OCCASIONAL GUSTS TO 20 KT
THIS AFTERNOON. SEAS 2 TO 3 FEET.
OUTLOOK...
WINDS AND SEAS WILL REMAIN BELOW SCA LEVELS OVERALL. SCATTERED
SHOWERS/TSTMS WED THRU THURSDAY WILL LOCALLY CREATE HIGHER
WINDS/SEAS.
RIP CURRENTS...
LOWER WINDS/SEAS AND MEDIUM PERIOD SWELLS POINTS TO AN OVERALL
LOW-ENERGY SEA STATE. LOW RISK FOR RIP CURRENTS EXPECTED TODAY
AND WEDNESDAY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...GORSE
NEAR TERM...MPS
SHORT TERM...OHARA
LONG TERM...OHARA
AVIATION...MPS/OHARA
MARINE...MPS/OHARA
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