279
FXUS61 KPHI 051019
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
519 AM EST THU MAR 5 2026
WHAT HAS CHANGED
LAND DENSE FOG ADVISORY CANCELLED FOR COASTAL AREAS WHERE
WIDESPREAD VISIBILITY OF ONE QUARTER MILE OR LESS IS NO LONGER
ANTICIPATED.
EXTENDED MARINE DENSE FOG ADVISORY THROUGH THIS AFTERNOON WHERE
VISIBILITY WILL REMAIN BELOW MARINE THRESHOLDS.
KEY MESSAGES
1. PATCHY DENSE FOG IS EXPECTED THROUGH FRIDAY WITH INTERVALS OF
MAINLY LIGHT RAIN/SHOWERS.
2. TURNING VERY MILD THIS WEEKEND AND ESPECIALLY THE FIRST HALF OF
NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...PATCHY DENSE FOG IS EXPECTED THROUGH FRIDAY
WITH INTERVALS OF MAINLY LIGHT RAIN/SHOWERS.
FRONT STALLED MOSTLY TO OUR SOUTH THROUGH THE PERIOD WILL KEEP
THE WEATHER COOL AND MURKY, WITH WEAK WAVES OF LOW PRESSURE
BRINGING SEVERAL PERIODS OF MAINLY LIGHT RAIN. THE FIRST WILL
ARRIVE EARLY THIS MORNING, WITH A SECOND WAVE ARRIVING TONIGHT.
BETWEEN THESE RAINY INTERVALS, MIST/DRIZZLE AND PERHAPS SOME
DENSE FOG WILL DEVELOP AS THE COOL BUT VERY MOIST AIR MASS
LINGERS ACROSS THE REGION WITH RELATIVELY LIGHT WINDS. THE ONE
THING IN OUR FAVOR IS THAT WINDS MAY BE JUST STRONG ENOUGH TO
PREVENT WIDESPREAD DENSE FOG, ESPECIALLY AS REMAINING SNOW MELTS
AND GROUND TEMPS APPROACH AIR TEMPS, BUT THE RISK WILL CONTINUE.
HOWEVER, AS NO WIDESPREAD DENSE FOG IS CURRENTLY ANTICIPATED AT
LEAST TODAY, HAVE CANCELLED THE ADVISORY FOR THE COASTAL LAND
STRIP.
FRIDAY WILL FEATURE ANOTHER DAY OF DREARY CONDITIONS AS A BACKDOOR
FRONT WILL HAVE PUSHED THROUGH FROM THE NORTH AND EAST AND THEN
REMAIN STALLED FOR A TIME OVER DELMARVA. EXPECT LOTS OF CLOUDS
WITH SOME FOG, DRIZZLE OR A FEW SHOWERS AS LOW CLOUDS AND MOISTURE
REMAIN TRAPPED BELOW AN INVERSION. MOST OF OUR AREA SHOULD SEE
HIGHS IN THE 40S.
KEY MESSAGE 2...TURNING VERY MILD THIS WEEKEND AND ESPECIALLY THE
FIRST HALF OF NEXT WEEK.
A MUCH WARMER AIR MASS IS FORECAST TO OVERSPREAD OUR AREA THIS
WEEKEND AND ESPECIALLY THE FIRST HALF OF NEXT WEEK. IN ADDITION,
THERE WILL BE SOME OPPORTUNITIES FOR SHOWERS AND PERHAPS A
THUNDERSTORM ACROSS THE AREA.
A SHORTWAVE TROUGH IS FORECAST TO SLIDE ALONG THE NORTHERN SIDE OF A
BUILDING RIDGE THAT BECOMES ANCHORED/CENTERED IN THE WESTERN ATLANTIC
THROUGH FRIDAY. THE TROUGH SHOULD EXIT THE NEW ENGLAND COAST
FRIDAY MORNING, HOWEVER STRONG HIGH PRESSURE ACROSS EASTERN CANADA
IS FORECAST TO BUILD SOUTHWARD. AS THIS OCCURS, THE RIDGE AMPLIFIES
WEST AND NORTHWARD ALOFT. THIS SETUP FORCES A BOUNDARY TO OUR
SOUTH AND WEST WITH AN EAST TO NORTHEAST LOW- LEVEL FLOW. THIS
WILL DRIVE A COLDER AIR MASS ACROSS OUR REGION ALONG WITH MORE
CLOUD COVER AND PERHAPS SOME FOG. THIS COLD AIR DAMMING SCENARIO
WILL LIKELY LEAD TO A STRONG TEMPERATURE GRADIENT, ESPECIALLY
ON SATURDAY AS THE WEDGE OF COLDER AIR STARTS TO ERODE FROM THE
SOUTH. AS A RESULT, THE NBM HAS CONTINUED A COOLING TREND FOR
FRIDAY AND THEREFORE USED A NBM/NBM10 BLEND FOR TEMPERATURES TO
GET IT A BIT COLDER. GIVEN THE CONTINUED COOLING, MAY HAVE TO
WATCH FRIDAY MORNING ACROSS THE I-80 CORRIDOR FOR SOME LIGHT
FREEZING RAIN IF SOME PRECIPITATION IS AROUND.
ANOTHER UPPER-LEVEL DISTURBANCE TRACKS TO THE NORTH OF OUR AREA
SATURDAY NIGHT, WITH A TRAILING COLD FRONT MOVING THROUGH. THIS
LOOKS TO BRING ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM TO OUR
REGION, ALTHOUGH THE TRENDS IN THE LATEST MODEL GUIDANCE LOOKS TO BE
LOWERING WITH THE COVERAGE OF SHOWERS. AS OF NOW, DID NOT MAKE ANY
CHANGES TO THE NBM POPS FOR SATURDAY NIGHT. AN INCREASE IN THE LOW-
LEVEL WARM AIR ADVECTION AHEAD OF A WEAKENING COLD FRONT LOOKS TO
ERODE THE WEDGE OF COLDER AIR FROM SOUTH TO NORTH, THEREFORE HIGH
TEMPERATURES SATURDAY FOR MUCH OF OUR AREA LOOK TO OCCUR DURING
SATURDAY NIGHT. USED A NBM/NBM10 BLEND FOR TEMPERATURES SATURDAY
INTO SATURDAY NIGHT TO SHOW A SLOWER EROSION OF THE LOW-LEVEL COLDER
AIR. WE BECOME MORE EMBEDDED WITHIN THE WARM SECTOR SUNDAY AND
ESPECIALLY EARLY NEXT WEEK WITH SURFACE HIGH PRESSURE ANCHORED IN
THE WESTERN ATLANTIC AND A SOUTH TO SOUTHWEST FLOW. THIS SHOULD
RESULT IN A MUCH WARMER AIR MASS SURGING INTO THE REGION. HIGHS
SUNDAY AND MONDAY ARE FORECAST TO BE IN THE 60S FOR MUCH OF THE
AREA, THEN INTO THE LOW TO MID 70S FOR TUESDAY AND WEDNESDAY. THE
FLOW MAY BE LIGHT ENOUGH AND ALSO MORE SOUTHERLY THOUGH SUNDAY AND
EARLY NEXT WEAK, WHICH WOULD INTRODUCE SIGNIFICANT COOLING ALONG THE
COAST WITH PERHAPS EVEN A ROBUST SEA BREEZE RACING INLAND. SOME
GUIDANCE IS FASTER WITH A COLD FRONT AND RIPPLE OF LOW PRESSURE
WEDNESDAY, AND IF THIS OCCURS THEN TEMPERATURES MAY NOT GET INTO THE
70S.
AVIATION /10Z THURSDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...IFR/LIFR CONDITIONS EXPECTED THROUGH THE DAY. LIGHT TO
MODERATE RAIN EXPECTED THROUGH THE MORNING, WITH LIGHT SHOWERS,
LOW CLOUDS, AND FOG TAKING OVER FOR THE AFTERNOON. LIGHT WINDS
AROUND 5 KT EXPECTED OUT OF THE EAST. MODERATE CONFIDENCE IN
EXTENT OF RESTRICTIONS, WITH LOW CONFIDENCE IN TIMING AND IF
THERE IS ANY IMPROVEMENT THROUGH THE DAY.
TONIGHT...IFR/LIFR CONDITIONS LIKELY CONTINUE WITH FOG, THEN SOME
RAIN RETURNING, THEN MORE FOG TOWARD DAWN. EAST-NORTHEAST WINDS
AROUND 5 KT. LOW CONFIDENCE OVERALL.
OUTLOOK...
FRIDAY...SUB-VFR CONDITIONS DUE TO LOW CLOUDS AND POSSIBLE FOG. A
FEW SHOWERS POSSIBLE.
SATURDAY...SUB-VFR CEILINGS MAY TRY AND IMPROVE. SOME SHOWERS,
ESPECIALLY AT NIGHT, WITH SOME THUNDER POSSIBLE.
SUNDAY...CONDITIONS MAY IMPROVE TO VFR. A FEW SHOWERS STILL POSSIBLE.
MONDAY...MAINLY VFR.
MARINE
WINDS AND SEAS WILL REMAIN MAINLY BELOW SCA CONDITIONS THROUGH
TONIGHT. A SLOW MOVING FRONT WILL KEEP CLOUDS AND SHOWERS ON
THE WATERS DURING THE PERIOD. ALSO, WITH THE COLD WATERS AND
HUMID AIRMASS, FOG IS EXPECTED TO CONTINUE. A DENSE FOG
ADVISORY HAS BEEN EXTENDED THRU THE DAY. AS A WEAK WAVE PASSES
LATER TODAY INTO TONIGHT, WINDS MAY APPROACH SCA CRITERIA ON OUR
NORTHERN OCEAN WATERS, BUT AT THIS TIME CONFIDENCE IS LOW SO
HELD OFF ON ANY SCA.
OUTLOOK...
FRIDAY...NORTHEAST WINDS SHOULD BE DECREASING, AND AS OF NOW THE
CONDITIONS ARE ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY
CRITERIA. SOME FOG POSSIBLE.
SATURDAY AND SUNDAY...A PERIOD OF SMALL CRAFT ADVISORY CONDITIONS
POSSIBLE LATE SATURDAY INTO EARLY SUNDAY.
MONDAY...THE CONDITIONS ARE ANTICIPATED TO BE BELOW SMALL CRAFT
ADVISORY CRITERIA
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-431-
450>455.
DISCUSSION...GORSE/OHARA/RCM
AVIATION...GORSE/RCM
MARINE...GORSE/RCM
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