359
FXUS61 KPHI 102350
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
650 PM EST SUN NOV 10 2024
SYNOPSIS
A COLD FRONT THAT CROSSES THROUGH THE REGION ON MONDAY. A SECONDARY
COLD FRONT FOLLOWS FOR TUESDAY BEFORE HIGH PRESSURE RETURNS
WEDNESDAY. ANOTHER PAIR OF A WARM FRONT THEN A WEAK COLD FRONT MAY
MOVE THROUGH THE REGION ON THURSDAY. HIGH PRESSURE IS EXPECTED TO
BUILD IN OVER THE WEEKEND.
NEAR TERM /THROUGH MONDAY/
THE NEAR TERM FORECAST REMAINS ON TRACK. A LOW PRESSURE SYSTEM
TRACKING THROUGH THE GREAT LAKES WILL CONTINUE TO MOVE EASTWARD
INTO SOUTHERN CANADA TONIGHT. AN ASSOCIATED WARM FRONT WILL LIFT
NORTH OF THE AREA THIS EVENING BEFORE A TRAILING COLD FRONT
SWEEPS ACROSS THE AREA ON MONDAY MORNING.
LOOKING FORWARD TO THE REST OF THIS EVENING, PERIODS OF LIGHT
TO AT TIMES MODERATE RAIN WILL BEGIN TO OVERSPREAD THE REGION.
AS THE WARM FRONT LIFTS NORTH, WE WILL BEGIN TO SEE SOUTHERLY
BREEZES INCREASE WHERE GUSTS UP TO 20 MPH MAY OCCUR. ALSO, LOWS
SHOULD REMAIN RELATIVELY UNIFORM AND LEVEL THROUGH MUCH OF THE
NIGHT IN THE MID 50S TO AROUND 60 DEGREES. FOR MANY, THIS DAMP
AND MILD NIGHT WILL BE OUR FIRST MEASURABLE RAINFALL EVENT SINCE
LATE SEPTEMBER. PERIODS OF RAIN WILL CONTINUE WELL INTO THE
OVERNIGHT, BUT SHOULD BEGIN TO TAPER OFF FROM WEST TO EAST EARLY
MONDAY MORNING. IN TOTAL, EXPECTING ANYWHERE FROM 1/4 TO 1/2
INCH OF QPF, WITH LOCALLY HIGHER AMOUNTS UP TO 3/4 OF AN INCH
POSSIBLE.
HEADING INTO MONDAY, THE COLD FRONT WILL MOVE THROUGH THE AREA AND
BE LOCATED OFFSHORE BY THE AFTERNOON. SOME SHOWERS MAY LINGER
ESPECIALLY NEAR THE COAST AND OVER THE DELMARVA INTO THE LATE
MORNING HOURS, BUT CLEARING SKIES AND A MOSTLY SUNNY AFTERNOON IS IN
STORE FOR ALL. GUSTY WINDS SHOULD CONTINUE THROUGH MUCH OF MONDAY AS
WELL BEHIND THE FRONT WITH GUSTS UPWARDS OF 25 MPH POSSIBLE. DESPITE
THE FRONTAL PASSAGE, ANOTHER MILD DAY IS EXPECTED WITH HIGHS IN THE
MID 60S TO LOW 70S AS THE COLDER/DRIER AIR BEHIND THE FRONT, WILL
NOT ADVECT INTO THE AREA UNTIL MONDAY NIGHT.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
A MID LEVEL SHORTWAVE TROUGH WILL APPROACH AND PASS NORTH OF THE
REGION MONDAY NIGHT INTO TUESDAY. AT THE SURFACE A SECONDARY COLD
FRONT WILL SWEEP THROUGH OUR REGION; THE FRONT SHOULD BE SOUTH AND
EAST OF OUR REGION LIKELY BY SUNRISE TUESDAY MORNING. ALTHOUGH THIS
WILL BE THE STRONGER OF THE TWO COLD FRONTS IN TERMS OF TEMPERATURE
GRADIENT, THERE IS LITTLE OPPORTUNITY FOR MOISTURE ADVECTION BETWEEN
THE TWO FRONTS, SO NO PRECIPITATION IS EXPECTED. HIGH TEMPERATURES
ON TUESDAY ARE EXPECTED TO BE 10 TO 15 DEGREES LOWER THAN MONDAY'S
HIGHS, RANGING FROM THE MID 40S TO NEAR 60. IN ADDITION TO THE
COOLER AIR, DRY AIR ADVECTION AND GUSTY WINDS ARE ALSO EXPECTED IN
THE WAKE OF THE FRONT. CONSEQUENTLY, THIS COULD SET THE STAGE FOR
ANOTHER RISK OF FIRE SPREAD (SEE THE FIRE WEATHER SECTION BELOW).
A NORTH WIND WILL PERSIST TUESDAY NIGHT AS HIGH PRESSURE BUILDS INTO
THE REGION, HELPING USHER IN THE COLD AIRMASS. OVERNIGHT LOWS WILL
DROP INTO THE UPPER 20S TO LOW 30S WITH MID 30S FOR THE IMMEDIATE
COAST. WEDNESDAY WILL BE A FEW DEGREES COOLER THAN ON TUESDAY, WITH
HIGHS ONLY REACHING THE LOW 50S FOR MOST UNDER MOSTLY SUNNY
SKIES.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
MOSTLY TRANQUIL WEATHER IS EXPECTED THROUGH THIS PERIOD. MOST OF
THIS PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE OVER OUR
REGION - ESPECIALLY FOR THE WEEKEND. SEASONABLE TEMPERATURES
EXPECTED TO CLOSE OUT THE WORK WEEK WITH TEMPERATURES WARMING
OVER THE WEEKEND.
THE ONE EXCEPTION IS THAT ANOTHER SURFACE LOW COULD GET CLOSE ENOUGH
TO THE REGION ON THURSDAY FOR A CHANCE FOR PRECIPITATION, BUT IT IS
HIGHLY UNCERTAIN. A FAIRLY STRONG UPPER LEVEL TROUGH WILL MOVE
TOWARDS AND ACROSS THE EAST COAST WITH A WEAKENING FRONTAL SYSTEM AT
THE SURFACE DURING THIS PERIOD. SOME GUIDANCE DEPICTS THIS TAKING A
MORE NORTHERN TRACK (CLOSER TO OUR REGION), WHILE OTHER MODELS
DEPICT THIS LOW GOING WELL SOUTH OF OUR REGION. IF THE NORTHERN
TRACK VERIFIES, THEN ANOTHER ROUND OF PRECIPITATION WOULD BE
POSSIBLE ON THURSDAY. HOWEVER, THE SOUTHERN TRACK WOULD KEEP OUR
REGION DRY.
WHILE SOME GUIDANCE STILL DEPICTS COASTAL LOW DEVELOPMENT THEREAFTER
FOR THE THURSDAY NIGHT INTO FRIDAY TIMEFRAME, IT DEPICTS IT TOO FAR
AWAY FROM OUR REGION TO HAVE ANY IMPACT ON RAIN CHANCES. RATHER, DRY
CONDITIONS SHOULD RETURN LATE IN THE WEEK INTO NEXT WEEKEND.
AVIATION /00Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...CEILINGS ARE ANTICIPATED TO LOWER TO MVFR BETWEEN
02Z-04Z AND EVENTUALLY LOWER TO IFR BY 04Z-07Z FOR MOST
TERMINALS AS PERIODS OF LIGHT TO MODERATE RAIN OVERSPREAD THE
REGION. SOUTHWEST WINDS AROUND 8-13 KT WITH OCCASIONAL GUSTS UP
TO 20 KT. TEMPORARY VISIBILITY RESTRICTIONS POSSIBLE. MODERATE
CONFIDENCE.
MONDAY...LINGERING MVFR/IFR CEILINGS EARLY, SHOULD IMPROVE TO VFR BY
12Z-15Z FROM WEST TO EAST. CLEARING SKIES IN THE AFTERNOON. WEST
WINDS AROUND 10-15 KT WITH GUSTS UP TO 20-25 KT. HIGH CONFIDENCE.
OUTLOOK...
MONDAY NIGHT...VFR. BREEZY W-WNW WINDS 5 TO 10 KT WITH GUSTS UP
TO 15 KT.
TUESDAY...VFR WITH GUSTY NORTHWEST WINDS UP TO 25 KT.
WEDNESDAY...VFR.
THURSDAY...MAINLY VFR. SUB-VFR POSSIBLE WITH A CHANCE OF RAIN
SHOWERS.
FRIDAY...VFR.
MARINE
A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL ATLANTIC COASTAL WATERS
UNTIL 1 PM ON MONDAY. A SMALL CRAFT ADVISORY IS ALSO IN EFFECT FOR
THE DELAWARE BAY BEGINNING AT 6 PM TONIGHT UNTIL 6 AM MONDAY.
SOUTH-SOUTHWEST WINDS WILL CONTINUE TO INCREASE THROUGH THE
OVERNIGHT WITH WINDS AROUND 20-25 KT WITH WIND GUSTS UP TO 30 KT. A
FEW OCCASIONAL GUSTS UP TO 35 KT POSSIBLE. WINDS WILL GRADUALLY
BECOME MORE WESTERLY ON MONDAY WITH WINDS OF 20-25 KT IN THE MORNING
DIMINISHING TO 15-20 KT IN THE AFTERNOON. SEAS AROUND 4-6 FEET.
PERIODS OF LIGHT TO MODERATE RAIN LIKELY WITH FAIR WEATHER RETURNING
BY MONDAY AFTERNOON.
OUTLOOK...
MONDAY NIGHT THROUGH TUESDAY NIGHT...SCA CONDITIONS LIKELY. NW WIND
GUSTS AROUND 25 KT AND SEAS AROUND 5 FEET.
WEDNESDAY THROUGH FRIDAY...WINDS AND SEAS SHOULD STAY BELOW SCA
CRITERIA.
FIRE WEATHER
RELATIVE HUMIDITIES ARE CURRENTLY IN 40-60% RANGE FOR MOST OF THE
AREA THIS AFTERNOON. WITH DEW POINTS CONTINUING TO INCREASE AND
LIGHT RAIN EXPECTED TO MOVE INTO THE REGION TONIGHT, A WETTING RAIN
OF 0.25-0.50 INCHES IS EXPECTED THROUGH MONDAY MORNING. THIS WILL
HALT THE THREAT FOR ENHANCED FIRE RISK AT THIS TIME.
FOR MONDAY AND TUESDAY, ANOTHER PERIOD OF DRYING CONDITIONS ARE
EXPECTED BEHIND A COUPLE OF COLD FRONTS. MIN RH VALUES ARE EXPECTED
TO BE AROUND 45-60% ON MONDAY WITH WIND GUSTS UP TO 25 MPH. MIN RH
VALUES ON TUESDAY WILL MOSTLY BE AROUND 35-45% WITH GUSTS UP TO 25-
30 MPH.
CLIMATE
RECORD STRETCH (CONSECUTIVE DAYS) WITHOUT MEASURABLE
PRECIPITATION:
CURRENT
SITE RECORD RECORD DATES THRU 11/9
AC AIRPORT (ACY) 34 DAYS AUG-SEP 1995 38 DAYS
AC MARINA (55N) 39 DAYS AUG-SEP 1995 39 DAYS
GEORGETOWN (GED) 34 DAYS OCT-NOV 2001 43 DAYS
PHILADELPHIA (PHL) 29 DAYS OCT-NOV 1874 42 DAYS
TRENTON (TTN) 38 DAYS APR-MAY 1903 42 DAYS
WILMINGTON (ILG) 34 DAYS JAN-FEB 1909 42 DAYS
THESE STRETCHES WILL LIKELY END TONIGHT, BUT THERE IS
UNCERTAINTY IF THESE SITES WILL HAVE MEASURABLE PRECIPITATION
BEFORE MIDNIGHT. IF THEY DON'T, THEN ANOTHER DAY WILL BE ADDED
ON TO THE STRETCH.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...AIR QUALITY ALERT UNTIL 9 PM EST THIS EVENING FOR NJZ017>020-
026-027.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR ANZ430-431.
SMALL CRAFT ADVISORY UNTIL 1 PM EST MONDAY FOR ANZ450>455.
SYNOPSIS...MJL
NEAR TERM...AKL/DESILVA
SHORT TERM...JOHNSON/MJL
LONG TERM...JOHNSON/MJL
AVIATION...AKL/DESILVA/MJL
MARINE...DESILVA/MJL
FIRE WEATHER...WFO PHI
CLIMATE...WFO PHI
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