029
FXUS61 KPHI 280649
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
249 AM EDT MON APR 28 2025
SYNOPSIS
HIGH PRESSURE SHIFTS TO OUR SOUTH AND EAST TODAY INTO TONIGHT.
A WARM FRONT ARRIVES ON TUESDAY, FOLLOWED BY A COLD FRONT BY
WEDNESDAY. HIGH PRESSURE BRIEFLY RETURNS FOR WEDNESDAY
NIGHT INTO THURSDAY. ANOTHER LOW PRESSURE SYSTEM TRACKS TO OUR
NORTH ON FRIDAY WITH A COLD FRONT CROSSING THROUGH BY EARLY
SATURDAY. HIGH PRESSURE BUILDS BACK IN BY SUNDAY.
NEAR TERM /THROUGH TONIGHT/
A WARM AFTERNOON WITH MUCH LESS WIND, HOWEVER SEA AND BAY BREEZES
WILL OFFER SOME COOLING CLOSER TO THE COASTS.
AS A CLOSED LOW CONTINUES TO SHIFT SOUTH AND EAST OF NOVA SCOTIA
CANADA TODAY, THE FLOW ALOFT OVER OUR REGION WILL BECOME MORE
ANTICYCLONIC. A MID LEVEL RIDGE AXIS GETS CLOSER BY THE END OF THE
DAY AND THIS WILL DELIVER SURFACE HIGH PRESSURE INTO OUR AREA. THIS
WILL RESULT IN MUCH LESS WIND COMPARED TO YESTERDAY. A LIGHT
NORTHWEST TO NORTH SURFACE WIND THIS MORNING SHIFTS MORE OUT OF THE
SOUTH OR SOUTHWEST. AMPLE BOUNDARY LAYER WARMING THROUGH THE DAY ON
LAND COUPLED WITH STILL A CHILLY OCEAN AND LIGHT FLOW WILL RESULT IN
SEA/BAY BREEZES BY EARLY AFTERNOON. THIS WILL LOCALLY INCREASE THE
WINDS SOME AND ALSO RESULT IN COOLING CLOSER TO THE COAST.
TEMPERATURES ARE FORECAST TO TOP OUT INTO THE LOW TO MID 70S FOR
MUCH OF THE AREA, HOWEVER COOLER OR TURNING COOLER WHERE AFFECTS
FROM THE SEA/BAY BREEZES ARE REALIZED. IT WILL ALSO BE A BIT COOLER
IN THE HIGHER ELEVATIONS. A VERY DRY AIR MASS IN PLACE, AND WITH
PLENTY OF HEATING OF THE BOUNDARY LAYER THE DEW POINTS SHOULD REMAIN
ON THE LOWER SIDE. THE MODEL FORECAST SOUNDINGS SHOW SOME ADDITONAL
MIXING OUT OF THE DEW POINTS THROUGH ABOUT EARLY AFTERNOON FOLLOWED
BY SOME RECOVERY. DUE TO THE LIGHTER WINDS THOUGH, DEW POINTS MAY
NOT MIX OUT AS MUCH DURING PEAK HEATING. DEW POINTS SHOULD BE
HIGHEST CLOSEST TO THE COAST GIVEN THE FLOW SHIFTING TO ONSHORE
(SOUTHERLY).
AS WE GO THROUGH TONIGHT, THE AXIS OF THE MID LEVEL RIDGE SHOULD
CREST OVER OUR AREA. THIS WILL CONTINUE TO TAKE THE CENTER OF HIGH
PRESSURE MORE TO OUR SOUTH. THIS WILL FURTHER SUPPORT A SOUTH TO
SOUTHWESTERLY LOW-LEVEL WIND. GIVEN THE WEAK FLOW AND DECOUPLING AT
THE SURFACE, WINDS ARE EXPECTED TO QUICKLY GO LIGHT AND VARIABLE TO
EVEN CALM THROUGH THE EVENING. IT IS POSSIBLE THAT SOME HIGH LEVEL
CLOUDINESS IS ABLE TO CREST THIS RIDGE AXIS BY LATER TONIGHT,
HOWEVER A MAINLY CLEAR SKY IS FORECAST. TEMPERATURES DROP BACK INTO
THE MID AND UPPER 40S (LOW 50S IN SOME OF THE URBAN CENTERS).
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
DIFFUSE WARM FRONT WILL PUSH NORTHEASTWARD ACROSS THE REGION ON
TUESDAY IN ADVANCE OF AN APPROACHING COLD FRONT FROM THE NORTHWEST.
WE'LL ALREADY BE ABOVE NORMAL TODAY, BUT THIS SHOULD PUSH READINGS
FOR TUESDAY 10-15 IN THE PLUS SIDE, WITH MANY INLAND AREAS NEAR OR
ABOVE 80. EXCEPTION WILL BE THE POCONOS, WHERE 70S PREVAIL, AND
ESPECIALLY THE SHORE, WHERE A SEA BREEZE LIKELY KEEPS IT IN THE
CHILLY 60S.
SHOWERS AND STORMS WITH APPROACHING COLD FRONT ARE LIKELY DYING OUT
AS THEY MOVE INTO THE REGION DURING THE NIGHT TUESDAY. HAVE HIGH
CHANCE/LOW LIKELY POPS FOR FURTHEST REACHES OF THE POCONOS, RAMPING
DOWN QUICKLY TO BELOW SLIGHT CHANCE ALONG I-95. LATEST OUTLOOK AT
TIME OF WRITING PLACES POCONOS IN A MARGINAL RISK FOR SEVERE WEATHER
FROM ANY DYING STRONGER STORMS WHICH MAKE IT IN, PERHAPS HELPED
ALONG BY HIGHER DCAPE SINCE LOW LEVELS WILL BE A LITTLE DRY. LOWS
WILL BE IN THE 50S POCONOS AND SHORE, BUT THE MILD 60S ELSEWHERE
THANKS TO SOUTHERLY FLOW AND CLOUDS JUST AHEAD OF THE FRONT.
FRONT SLIDES SOUTH ACROSS THE REGION DURING THE MORNING AND MIDDAY
WEDNESDAY. THE PROGRESS LOOKS A LITTLE SLOWER, SO TEMPS WILL BE
NOTICEABLY COOLER IN THE POCONOS (60S) BUT ONLY SLIGHTLY COOLER
ACROSS I-95 (NEAR 80), AND DELMARVA/FAR S NJ ACTUALLY LOOKS A BIT
WARMER, HELPED ALONG BY AN OFFSHORE FLOW BEHIND THE FRONT BEFORE
COLD ADVECTION REALLY GETS GOING. RISK OF CONVECTION ACROSS OUR
SOUTHERN ZONES WITH THE FRONT LOOKS MINIMAL, SO JUST HAVE SOME
SLIGHT CHANCE POPS IN CENTRAL DELMARVA.
HIGH PRESSURE IS MORE PROMINENT IN THE FORECAST FOR WEDNESDAY NIGHT,
WITH ENOUGH CLEARING, DRIER AIR AND RADIATIONAL COOLING TO MAKE IT
NOTICEABLY COOLER THAN TUESDAY NIGHT ACROSS THE BOARD. LOWS MOSTLY
50S, 40S IN THE OUTLYING AREAS OF NJ AND PA AND CLOSE TO 40 IN THE
COOLEST PARTS OF THE POCONOS.
LONG TERM /THURSDAY THROUGH SUNDAY/
HIGH PRESSURE WILL BEGIN RETREATING EASTWARD AGAIN FOR THURSDAY,
WITH INCREASING CLOUDS AND PERHAPS A STRAY SHOWER LATER IN THE DAY
ACROSS WESTERN AREAS AS ANOTHER WARM FRONT APPROACHES. HIGHS MOSTLY
70S, 60S SHORE AND POCONOS.
BETTER CHANCE OF SHOWERS THURSDAY NIGHT AND FRIDAY AS THE WARM FRONT
LIFTS THROUGH ON THE SOUTHEAST SIDE OF LOW PRESSURE PASSING TO OUR
NORTHWEST. THIS WILL HOLD LOWS UP THURSDAY NIGHT, GENERALLY ABOUT 10
DEGREES MILDER THAN WEDNESDAY NIGHT, WITH 50S AND 60S COMMON. SHOULD
BREAK INTO THE WARM SECTOR FOR FRIDAY, WITH MOST AREAS OUTSIDE THE
POCONOS AND SHORE REACHING THE 80S AGAIN...70S POCONOS AND SHORE.
SHOWERS AND T-STORMS LIKELY IMPACT THE AREA LATER FRIDAY INTO FRIDAY
NIGHT AS THE AFOREMENTIONED COLD FRONT PUSHES ACROSS THE REGION.
STILL LOTS OF UNCERTAINTY ABOUT INTENSITY, BUT WE'LL BE WATCHING ANY
SEVERE WEATHER RISK CLOSELY.
LATEST GUIDANCE GENERALLY HAS THE FRONT CLEAR OUR REGION BY EARLY
SATURDAY, WITH A SIGNIFICANTLY COOLER COUPLE OF DAYS FOR NEXT
WEEKEND. HIGHS WILL MOSTLY BE NEAR 70 BOTH DAYS WITH 60S POCONOS.
WILL NEED TO WATCH POTENTIAL FOR LINGERING CLOUDS OR EVEN A SHOWER
WRAPPING IN BEHIND THE FRONT WITH THE UPPER LOW FOR SATURDAY, BUT
SUNDAY IS MORE LIKELY TO BE RELATIVELY DRY AND SUNNY. LOWS SATURDAY
NIGHT WILL BE ON THE COOL SIDE AGAIN, WITH 40S COMMON, 30S IN THE
POCONOS.
AVIATION /07Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR. LIGHT AND VARIABLE TO NORTH-NORTHWEST WINDS AROUND 5
KNOTS THROUGH THIS MORNING, BECOME SOUTHWEST AROUND 5 KNOTS AFTER
ABOUT 16Z. SEA/BAY BREEZES ARE EXPECTED TO AFFECT KACY, KMIV AND
KILG THIS AFTERNOON. MODERATE CONFIDENCE.
TONIGHT...VFR. WINDS BECOMING LIGHT AND VARIABLE TO LOCALLY CALM.
HIGH CONFIDENCE.
OUTLOOK...
VFR CONDITIONS SHOULD PREVAIL TUESDAY. SLIGHT CHANCE OF SHOWERS
TUESDAY NIGHT WITH PASSING COLD FRONT MAY RESULT IN BRIEF
REDUCTIONS, BUT UNLIKELY. VFR SHOULD THEN PREVAIL AGAIN WEDNESDAY
AND WEDNESDAY NIGHT. SLIGHT CHANCE OF SHOWERS RETURNS THURSDAY WITH
REDUCTIONS POSSIBLE, BUT THESE ARE MORE LIKELY FRIDAY INTO FRIDAY
NIGHT WHEN SHOWERS MAY BE ACCOMPANIED BY THUNDER.
MARINE
THE CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA THROUGH TONIGHT. WINDS WILL BE SHIFTING TO MORE SOUTHERLY
TODAY AND WITH A SEA AND BAY BREEZE DEVELOPING, SOME INCREASE IN THE
WINDS SHOULD OCCUR FOR A TIME THIS AFTERNOON ESPECIALLY
NEARSHORE.
OUTLOOK...
INCREASING SOUTH-SOUTHWESTERLY FLOW AS A WARM FRONT MOVES NORTH OF
THE REGION TUESDAY LIKELY BRINGS SCA CONDITIONS TO THE OCEAN, WITH
WINDS GUSTING 25-30 KTS FOR THE NJ-ADJACENT OCEAN WATERS BY
AFTERNOON AND SEAS BUILDING UP TO 6 FEET. FURTHER SOUTH, THESE
LIKELY WAIT TIL THE EVENING ACROSS THE WATERS CLOSER TO THE DELAWARE
COAST. NOT EXPECTING SCA GUSTS ON THE BAY, SO NO HEADLINE PRESENT OR
EXPECTED THERE JUST YET.
CONDITIONS LIKELY SUBSIDE BELOW SCA LEVELS DURING THE MORNING
WEDNESDAY AS A COLD FRONT SLIPS SOUTH OF THE AREA. SUB-SCA
CONDITIONS SHOULD THEN PREVAIL THROUGH THURSDAY BEFORE RETURNING TO
SCA ON SOUTHERLY FLOW AHEAD OF THE NEXT COLD FRONT ON FRIDAY. THIS
FRONT COULD ALSO BE ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
FIRE WEATHER
FOR TODAY, THE CONDITIONS WILL BE VERY DRY WITH MINIMUM RELATIVE
HUMIDITY IN THE 20-30 PERCENT RANGE. HOWEVER, THE WINDS WILL BE
MUCH LIGHTER (10 MPH OR LESS). SEA BREEZES NEAR COASTAL AREAS
WITH WIND SPEEDS AROUND 10 MPH SHOULD RESULT IN SOME RECOVERY
IN THE RELATIVE HUMIDITY. GIVEN THE MUCH LIGHTER WINDS THAT ARE
FORECAST, THE RISK FOR RAPID FIRE SPREAD IS MUCH LESS TODAY.
FOR TUESDAY, DEW POINTS WILL BE HIGHER, MOSTLY 40S TO LOW 50S, BUT
THE INCREASED WARMTH WILL HOLD RH'S DOWN, WITH MANY LOCALES LIKELY
DROPPING BACK TO NEAR 30 PERCENT AWAY FROM THE MARINE INFLUENCE.
WINDS WILL ALSO BE STRONGER, WITH GUST OF 20-25 MPH LIKELY IN
THE AFTERNOON. THUS, THERE MAY YET AGAIN BE A NEED FOR A SPECIAL
WEATHER STATEMENT.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TUESDAY TO 6 AM EDT WEDNESDAY
FOR ANZ450>453.
SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM EDT WEDNESDAY
FOR ANZ454-455.
SYNOPSIS...DESILVA/RCM
NEAR TERM...GORSE
SHORT TERM...RCM
LONG TERM...RCM
AVIATION...GORSE/RCM
MARINE...GORSE/RCM
FIRE WEATHER...GORSE/RCM
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