074
FXUS61 KPHI 101845
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
245 PM EDT SAT MAY 10 2025
SYNOPSIS
A WEAK COLD FRONT SLIDES THROUGH TONIGHT, WITH HIGH PRESSURE
RETURNING FOR THE BACK HALF OF THE WEEKEND AND START OF NEXT
WEEK. HIGH PRESSURE MOVES OUT ON MONDAY NIGHT, WITH AN AREA OF
LOW PRESSURE MOVING IN FOR THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH SUNDAY/
A NICE SATURDAY IS ONGOING, ALBEIT A BIT BREEZY. SUNNY SKIES AND
BREEZY WINDS CONTINUE THROUGH THE AFTERNOON WITH GUSTS UP TO 35
MPH POSSIBLE.
FOR TONIGHT, A COLD FRONT COMES THROUGH, THOUGH THE IMPACT WILL
JUST BE SOME HIGH CLOUDS AS THE FRONT IS VERY MOISTURE STARVED.
MOST OF THE CLOUDS WILL BE AROUND AND SOUTH OF THE PHILADELPHIA
METRO, KEEPING TEMPERATURES A FEW DEGREES WARMER, WITH LOWS IN
THE LOW TO MID 50S. FURTHER NORTH, SKIES WILL BE MORE CLEAR AND
WINDS LIGHT, RESULTING IN FAVORABLE RADIATIONAL COOLING
CONDITIONS. THIS WILL RESULT IN LOWS IN THE MID TO UPPER 40S.
FOR TOMORROW, HIGH PRESSURE BEGINS TO BUILD IN FROM THE
NORTHWEST, WITH A STRENGTHENING UPPER LEVEL RIDGE DEVELOPING
OVER THE AREA. WILL SEE SOME CIRRUS TOMORROW, ESPECIALLY FOR THE
SOUTHERN 2/3RDS OF THE AREA AS AN UPPER LEVEL LOW SPINS TO THE
SOUTHWEST. STILL WILL BE WARM THOUGH WITH MODEST HEIGHT RISES
UNDER THE RIDGE AND HIGH TEMPERATURES IN THE 70S AND EVEN LOW
80S ACROSS FAR SOUTHERN NJ AND SOUTHERN DELMARVA. WHILE RHS WILL
FALL INTO THE UPPER 20S/LOW 30S, WINDS WILL BE 10 MPH OR LESS,
WHICH WILL LIMIT FIRE SPREAD CONCERNS.
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
UPPER LEVEL RIDGE WILL BE BUILDING ACROSS THE REGION SUNDAY
NIGHT, KEEPING THE WEATHER DRY, THOUGH A CLOSED LOW PRESSURE
CENTERED OVER THE WESTERN GULF COAST WILL BEGIN TO SPREAD SOME
HIGH LEVEL CIRRUS CLOUDS NORTHWARD ACROSS THE REGION. LOWS WILL
BE IN THE 40S NORTH, 50S CENTRAL AND SOUTH.
THE AFOREMENTIONED CLOSED LOW WILL SLOWLY MOVE NORTHEASTWARD
INTO THE REGION AS WE HEAD THROUGH MONDAY AND TUESDAY, RESULTING
IN INCREASING CLOUDS MONDAY FOLLOWED BY INCREASING CHANCES OF
SHOWERS MONDAY NIGHT INTO TUESDAY. MONDAY, AT LEAST, SHOULD
REMAIN DRY HOWEVER, WITH HIGHS IN THE 70S TO NEAR 80, EXCEPT
COOLER NEAR THE WATER AND IN THE MOUNTAINS. SHOWERS START TO
INCREASE IN COVERAGE FROM THE SOUTHWEST MONDAY AFTERNOON, BUT
MORE WIDESPREAD COVERAGE IS EXPECTED LATE MONDAY NIGHT AND
TUESDAY. THAT HAVING BEEN SAID, WE'RE NOT LOOKING AT A FULL-ON
WASHOUT, WITH DRY INTERVALS EXPECTED AS WELL. TOTAL
PRECIPITATION AT LEAST THROUGH TUESDAY IS NOT LOOKING TO
IMPRESSIVE EITHER, WITH GENERALLY LESS THAN A QUARTER INCH
CLOSER TO NEW YORK CITY AND AROUND A HALF INCH FOR PARTS OF THE
DELMARVA. PHILLY METRO AND THE BULK OF OUR FORECAST AREA LIKELY
FALLS SOMEWHERE IN BETWEEN.
WITH MILDER AIR MOVING BACK NORTH AHEAD OF THE SYSTEM ALONG WITH
INCREASED CLOUD COVER PREVENTING RADIATIONAL COOLING, LOWS
MONDAY NIGHT SHOULD BE IN THE 50S NORTH, 60S SOUTH. HOWEVER,
CLOUDS AND SHOWERS LIKELY HOLD HIGHS ON TUESADY DOWN CLOSER TO
THE 70 DEGREE MARK. GIVEN A RELATIVELY STABLE ONSHORE
SOUTHEASTERLY FLOW AND PLENTY OF CLOUDS, INSTABILITY LOOKS
MEAGER, AND WE AREN'T PRESENTLY FORECASTING ANY THUNDERSTORMS
FOR TUESDAY.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
THE APPROACHING CLOSED LOW GRADUALLY OPENS BACK UP INTO A
SHORTWAVE TROUGH TUESDAY NIGHT AND WEDNESDAY AS IT CONTINUES
MOVING TOWARD US, THEN FINALLY PASSING OVERHEAD ON THURSDAY. AS
THE SYSTEM APPROACHES TUESDAY NIGHT THROUGH WEDNESDAY NIGHT,
SHOWER COVERAGE SHOULD REMAIN FAIRLY HIGH, AND SOME ELEVATED
INSTABILITY MAY BRING A FEW THUNDERSTORMS AS WELL, BUT OVERALL
NOT LOOKING AT A SIGNIFICANT SEVERE WEATHER RISK AT THIS TIME
FOR MOST OF OUR REGION GIVEN A CONTINUED ONSHORE FLOW AND CLOUDS
KEEPING SURFACE INSTABILITY MEAGER. LOWS BOTH NIGHTS SHOULD BE
SIMILAR, 50S NORTH AND 60S CENTRAL AND SOUTH, WITH HIGHS
WEDNESDAY SIMILAR TO TUESDAY, MOSTLY CLOSE TO 70, COOLER
MOUNTAINS/COAST AND WARMER CENTRAL DELMARVA.
SHOWER CHANCES START TO DECREASE THURSDAY AS THE TROUGH PASSES
BY ALOFT, AND WITH SOME ADDITIONAL BREAKS OF SUN, TEMPS SHOULD
RISE FURTHER INTO THE 70S FOR MOST OF THE REGION, PERHAPS
TOUCHING 80 IN A FEW WARMER SPOTS.
UPPER LEVEL RIDGE THEN BUILDS IN BRIEFLY THURSDAY NIGHT, BUT
WITHOUT MUCH MECHANISM FOR CLEAR OUT THE LOW LEVELS. THUS, THE
CHANCE OF SHOWERS DWINDLES CONSIDERABLY, BUT CLOUDS MAY LINGER,
AND LOWS WILL REMAIN MILD, MOSTLY 60S.
FRIDAY AND SATURDAY LOOK FAIRLY SIMILAR RIGHT NOW AS A NEW
CLOSED LOW PARKS ITSELF OVER THE GREAT LAKES. THIS BRING SOME
INCLEMENT WEATHER BACK TO OUR REGION, ESPECIALLY PARTS OF
PENNSYLVANIA WHICH WILL BE CLOSER TO THE LOW CENTER AS WELL AS
MORE INSTABLE WITH LESS MARINE INFLUENCE. SHOWERS WILL AGAIN BE
POSSIBLE, ESPECIALLY IN THE AFTERNOON HOURS, AND THUNDER MAY BE
A RISK AS WELL AS TEMPS SHOULD MANAGE THE 80S FOR MOST OF THE
REGION, ELEVATING INTABLITY. A WEAKENING COLD FRONT OR TWO
PROPAGATING SOUTHEASTWARD OUT FROM THE CLOSED LOW MAY MOVE
THROUGH ONE OR BOTH DAYS, FOCUSING ANY THUNDER RISK A BIT MORE,
BUT STILL A WAYS OUT TO GET A GOOD FOCUS ON THOSE DETAILS.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY (THROUGH 00Z)...VFR. NORTHWEST WINDS 10-20 KT AND
GUSTS 20-30 KT, DECREASING TO A 10 KT SUSTAINED WIND BETWEEN
21Z-22Z. HIGH CONFIDENCE.
TONIGHT...VFR. WINDS DECREASE QUICKLY TO AROUND 5 KT, GENERALLY
OUT OF THE WEST. PERIODS OF CALM OR LIGHT/VARIABLE POSSIBLE,
ESPECIALLY IN MORE SHELTERED AREAS. HIGH CONFIDENCE.
SUNDAY...VFR. NORTHWEST WINDS AROUND 10 KT. HIGH CONFIDENCE.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY...VFR.
MONDAY NIGHT...SHOWERS MOVING IN MAY BRING SOME REDUCTIONS BELOW
VFR, BUT VFR LIKELY PREDOMINATES.
TUESDAY THROUGH THURSDAY...INTERVALS OF SUB-VFR LIKELY WITH
SHOWERS AND PERHAPS A THUNDERSTORM, WITH INSTANCES OF IFR
POSSIBLE.
MARINE
A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL MARINE ZONES UNTIL 6
PM AS WIND GUSTS ARE AROUND 25-30 KT, MAINLY IN NEARSHORE AREAS
AND INLETS. SEAS 3 TO 4 FEET.
NO MARINE HEADLINES EXPECTED FOR TONIGHT AND TOMORROW AS WINDS
DIMINISH QUICKLY LATE THIS AFTERNOON. WESTERLY WINDS AROUND 10
KT THROUGH TOMORROW MORNING, BEFORE TAKING ON A MORE
EAST/SOUTHEAST DIRECTION IN THE AFTERNOON. SEAS 2 TO 3 FEET.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY NIGHT...NO MARINE HEADLINES
EXPECTED.
TUESDAY THROUGH WEDNESDAY NIGHT...WINDS AND SEAS MAY BUILD TO
LOW-END SMALL CRAFT ADVISORY LEVELS, WITH WORST CONDITIONS
EXPECTED LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL ALSO BE POSSIBLE.
THURSDAY...NO MARINE HEADLINES EXPECTED, THOUGH SHOWERS REMAIN
POSSIBLE.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ430-
431-450>455.
SYNOPSIS...HOEFLICH/RCM
NEAR TERM...HOEFLICH
SHORT TERM...RCM
LONG TERM...RCM
AVIATION...HOEFLICH/RCM
MARINE...HOEFLICH/RCM
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