152
FXUS61 KPHI 191306
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
906 AM EDT SUN APR 19 2026
WHAT HAS CHANGED
MARINE DENSE FOG ADVISORY HAS EXPIRED.
KEY MESSAGES
1. A STRONG COLD FRONT WILL BRING RAIN SHOWERS TO THE AREA THROUGH
EARLY THIS AFTERNOON.
2. FREEZE/FROST EARLY THIS WEEK AS MUCH COLDER AIR WILL BE
SETTLING IN, WITH A WIDESPREAD FREEZE POTENTIAL EARLY TUESDAY
MORNING. A RETURN TO ABOVE AVERAGE TEMPERATURES THEN OCCURS
LATER THIS WEEK.
DISCUSSION
KEY MESSAGE 1...A STRONG COLD FRONT WILL BRING RAIN SHOWERS TO THE
AREA THROUGH EARLY THIS AFTERNOON.
AS OF 7 AM, THE COLD FRONT IS CROSSING THROUGH THE LEHIGH VALLEY
AND NW NJ NOW, AND SHOULD CONTINUE TO PROGRESS THROUGH THE
REGION, MOVING OFF SHORE LATE THIS MORNING. COVERAGE OF SHOWERS
AHEAD OF THE FRONT HAS BEEN QUITE LIMITED THUS FAR, BUT STILL
EXPECTING COVERAGE OF SHOWERS TO INCREASE AS IT GETS CLOSER.
THAT BEING SAID, OVERALL, RAIN AMOUNTS ARE STILL EXPECTED TO BE
RATHER LIGHT - RANGING FROM A FEW HUNDREDTHS TO THREE QUARTERS
OF AN INCH.
THE RISK FOR OTHER THUNDERSTORM HAZARDS REMAINS QUITE LOW, ALTHOUGH
THANKS TO SOME ELEVATED INSTABILITY, CAN'T RULE OUT AN ISOLATED
THUNDERSTORM.
DUE TO THE STRONG COLD AIR ADVECTION BEHIND THE FRONT, HIGH
TEMPERATURES ARE LIKELY TO OCCUR EARLY IN THE DAY.
KEY MESSAGE 2...FREEZE/FROST EARLY THIS WEEK AS MUCH COLDER AIR
WILL BE SETTLING IN, WITH A WIDESPREAD FREEZE POTENTIAL EARLY
TUESDAY MORNING. A RETURN TO ABOVE AVERAGE TEMPERATURES THEN
OCCURS LATER THIS WEEK.
THE BIG CHANGE IS THAT THERE IS INCREASING CONFIDENCE THAT HIGHER
TERRAIN AREAS, PARTICULARLY THE SOUTHERN POCONOS, WILL SEE
TEMPERATURES NEAR OR BELOW FREEZING LATER TONIGHT INTO MONDAY
MORNING. A FREEZE WARNING HAS BEEN ISSUED FOR CARBON AND MONROE
COUNTIES WHERE THERE IS THE HIGHEST CONFIDENCE FOR BELOW FREEZING
TEMPERATURES. FOR SURROUNDING AREAS, PARTICULARLY THE LEHIGH
VALLEY AND NW NJ, IF WINDS DIMINISH QUICK ENOUGH, AND IF CLOUDS
DON'T BUILD IN UNTIL AFTER MIDNIGHT, THERE IS A RISK FOR NEAR
FREEZING TEMPERATURES AND PATCHY FROST DEVELOPMENT. HOWEVER, THE
RISK IN THESE AREAS IS VERY CONDITIONAL ON THE WINDS AND
CLOUDS. THEREFORE, WHILE THERE IS A CHANCE, CONFIDENCE IS TOO
LOW TO ISSUE A FROST ADVISORY AT THIS TIME.
THE CENTER OF COLD SURFACE HIGH PRESSURE WILL THEN SLIDE OVER
OUR REGION DURING MONDAY NIGHT BEFORE GRADUALLY SHIFTING OFFSHORE
DURING TUESDAY. THIS COMBINED WITH A CLEARING SKY, WINDS BECOMING
VERY LIGHT TO CALM AND LOW DEW POINTS WILL RESULT IN EFFICIENT
RADIATIONAL COOLING CONDITIONS MONDAY NIGHT. A WIDESPREAD FREEZE
LOOKS TO OCCUR EARLY TUESDAY MORNING, AND THE FREEZE WATCH HAS
BEEN EXPANDED TO INCLUDE MOST OF OUR AREA. ALL OF OUR COUNTIES
NOW HAVE AN ACTIVE GROWING SEASON DUE TO THE RECENT EXCESSIVE
WARMTH. BLOOMS/VEGETATION HAVE QUICKLY INITIATED AND IN SOME
CASES ARE AHEAD OF SCHEDULE. FRUIT TREES AND OTHER COLD SENSITIVE
PLANTS ALREADY PLANTED ARE THE MOST CONCERN. FROST FORMATION
MIGHT BE SOMEWHAT LIMITED GIVEN A MUCH DRIER LOW-LEVEL AIR MASS
IN PLACE. OUTSIDE OF THE URBAN CITY CENTERS AND AWAY FROM THE
IMMEDIATE COAST, TEMPERATURES ARE EXPECTED TO DROP BELOW
FREEZING. IN SOME CASES, WELL BELOW FREEZING.
HIGH TEMPERATURES BOTH MONDAY AND TUESDAY ARE FORECAST TO BE IN THE
40S AND 50S ACROSS THE REGION, WHICH IS SEVERAL DEGREES BELOW
AVERAGE. A FEW LIGHT RAIN/SNOW OR GRAUPEL SHOWERS ARE POSSIBLE ON
MONDAY AS THE CORE OF THE COLD AIR ALOFT IS OVERHEAD ALONG WITH SOME
MID LEVEL ENERGY SLIDING THROUGH WITH THE TROUGH AXIS. THE AIR MASS
BELOW CLOUD BASE LOOKS RATHER DRY AND THEREFORE ANYTHING THAT
DEVELOPS COULD BE MOSTLY VIRGA OUTSIDE OF THE HIGHER TERRAIN. IT
WILL FEEL MUCH COLDER MONDAY WITH A BREEZE AND THE VERY DRY AIR IN
PLACE. A RETURN, SOUTHERLY, FLOW WILL THEN BECOME ESTABLISHED
TUESDAY AND CONTINUE INTO WEDNESDAY. THIS ALONG WITH AN INCREASE IN
WARM AIR ADVECTION AND RISING HEIGHTS WILL RESULT IN TEMPERATURES
CLIMBING BACK ABOVE AVERAGE WEDNESDAY THROUGH SATURDAY.
AVIATION /13Z SUNDAY THROUGH THURSDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THROUGH 18Z...CEILINGS AND VISIBILITY ARE EXPECTED TO IMPROVE,
AND WINDS WILL ABRUPTLY SHIFT TO NORTHWESTERLY THOUGH 15Z AS A
COLD FRONT MOVES THROUGH. WINDS GUSTING UP TO 30 KT ARE POSSIBLE
BEHIND THE FRONT.
AFTER 18Z...LOWER CLOUDS AND RAIN SHOWERS WILL SLIDE EAST OFF
THE COAST, RESULTING IN A RETURN OF VFR CONDITIONS FROM WEST TO
EAST. WINDS WILL REMAIN OUT OF THE NORTHWEST, BUT BEGIN TO
SLOWLY DIMINISH AFTER 21Z. MODERATE CONFIDENCE.
TONIGHT...VFR CONDITIONS EXPECTED. WESTERLY WINDS NEAR OR BELOW
10KT. MODERATE CONFIDENCE.
OUTLOOK...
MONDAY...VFR. A FEW LIGHT/BRIEF SHOWERS OR SPRINKLES POSSIBLE DURING
THE DAY. WEST-NORTHWEST WIND GUSTS TO 20-25 KNOTS, QUICKLY
DIMINISHING AT NIGHT.
TUESDAY...VFR.
WEDNESDAY...AREAS OF SUB-VFR CONDITIONS ARE POSSIBLE AT TIMES DUE TO
SOME SHOWERS.
THURSDAY...VFR.
MARINE
VISIBILITY HAS IMPROVED AS A COLD FRONT MOVES THROUGH AND WIDNS
HAVE SHIFTED NORTHWESTERLY. THUS, THE MARINE DENSE FOG ADVISORY
EXPIRED AT 9 AM.
WINDS INCREASE QUICKLY BEHIND A COLD FRONT LATER THIS MORNING.
GUIDANCE HAS TRENDED WINDIER NEAR THE MOUTH OF THE DELAWARE BAY
AND DOWNSTREAM, WHICH IS NOT UNCOMMON IN THESE FLOW REGIMES DUE
TO FUNNELING EFFECTS ALONG THE BAY. THEREFORE, HAVE ISSUED A
GALE WARNING FOR THE LOWER DELAWARE BAY, THE NEAR COASTAL AREAS
(OUT TO 20 NM) FROM GREAT EGG INLET NJ TO FENWICK ISLAND DE, AND
THE FARTHER MARINE AREAS (20 TO 60 NM) FROM CAPE MAY NJ TO
FENWICK ISLAND DE.
FOR THE REST OF THE MARINE AREAS, WINDS ARE EXPECTED TO STAY
BETWEEN 25 AND 30 KT DURING THE DAY TIME, SO A SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR THE REST OF THE DELAWARE BAY AND
NEAR COASTAL AREAS (SCAS ARE NOT ISSUED FOR THE 20 TO 60 NM
MARINE AREAS).
ONCE WINDS DIMINISH BY EARLY THIS EVENING, WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW SCA CRITERIA THROUGH THE REST OF
TONIGHT.
OUTLOOK...
MONDAY...WIND GUSTS COULD BE AROUND 25 KNOTS FOR A TIME.
TUESDAY THROUGH THURSDAY...THE CONDITIONS ARE ANTICIPATED TO BE
BELOW SMALL CRAFT ADVISORY CRITERIA.
PHI WATCHES/WARNINGS/ADVISORIES
PA...FREEZE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING
FOR PAZ054-055-060>062-070-071-101>106.
FREEZE WARNING FROM 11 PM THIS EVENING TO 10 AM EDT MONDAY FOR
PAZ054-055.
NJ...FREEZE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING
FOR NJZ001-007>010-012-013-015>023-027.
DE...FREEZE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING
FOR DEZ001>003.
MD...FREEZE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING
FOR MDZ012-015-019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ430-
450>452.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ431-453>455-
485.
DISCUSSION...GORSE/JOHNSON
AVIATION...GORSE/JOHNSON
MARINE...GORSE/HOEFLICH/JOHNSON
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