462
FXUS61 KPHI 111809
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
109 PM EST MON NOV 11 2024
SYNOPSIS
A SECONDARY COLD FRONT FOLLOWS LATE TONIGHT INTO EARLY TUESDAY
BEFORE HIGH PRESSURE RETURNS WEDNESDAY. ANOTHER PAIR OF A WARM
FRONT THEN A WEAK COLD FRONT MAY APPROACH THE REGION ON
THURSDAY. HIGH PRESSURE IS EXPECTED TO BUILD IN OVER THE
WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THE COLD FRONT HAS NOW MADE ITS WAY OFF OUR COASTLINE. THIS
INITIAL FRONT WON'T BE TOO STRONG IN TERMS OF TEMPERATURE
CONTRAST BUT WILL START TO BRING DOWN THE DEW POINTS AS WINDS
SHIFT TO MORE OF A WESTERLY DIRECTION WITH SOME GUSTS UP TO 30
MPH POSSIBLE THIS AFTERNOON. WE STILL EXPECT HIGHS TO RANGE FROM
THE UPPER 50S/LOW 60S NORTH TO THE LOW 70S SOUTH WITH THE DAY
GENERALLY FEATURING A MIX OF SUN AND CLOUDS.
AS WE HEAD INTO TONIGHT, THE UPPER TROUGH AXIS SHIFTS THROUGH
ALOFT WITH A SECONDARY COLD FRONT MOVING THROUGH AT THE SURFACE.
A FAIRLY STRONG PRESSURE GRADIENT DEVELOPS IN ITS WAKE SO WINDS
SHOULD PICK UP OVERNIGHT OUT OF THE NW AFTER INITIALLY
DIMINISHING SOME IN THE EVENING. GENERALLY EXPECT WINDS BY THE
OVERNIGHT OF 10 TO 15 MPH WITH SOME HIGHER GUSTS POSSIBLE. EVEN
THOUGH THIS SECONDARY FRONT WILL BE STRONGER IN TERMS OF
TEMPERATURE CONTRAST, IT WILL LACK MOISTURE SO NO PRECIP IS
EXPECTED. EXPECT LOWS BY TUESDAY MORNING GENERALLY IN THE 40S
WITH UPPER 30S ACROSS THE POCONO PLATEAU.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
THE MAIN FEATURE IN THIS PERIOD WILL BE THE SECONDARY COLD FRONT
ON TUESDAY. THE FRONT SHOULD BE SOUTH AND EAST OF OUR REGION
EARLY IN THE DAY. 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. GUIDANCE DEPICTS RAPID PRESSURE
RISES BEHIND THE FRONT. CONSEQUENTLY, EXPECT WINDY CONDITIONS,
WIND GUSTS OF 25 TO 40 MPH WILL BE POSSIBLE DURING THE DAY TIME.
IN ADDITION TO THE COOLER AIR AND GUSTY WINDS, DRY AIR
ADVECTION IS 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).
SHORT WAVE RIDGING, BOTH AT THE SURFACE AND IN THE MID LEVELS,
BUILDS IN FOR WEDNESDAY, BRINGING A RETURN TO TRANQUIL
CONDITIONS (INCLUDING MUCH LOWER WIND SPEEDS).
LONG TERM /THURSDAY 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. 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. GUIDANCE HAS STARTED TO TREND TOWARDS A MORE
SOUTHERN TRACK OF THIS SYSTEM, WHICH WOULD KEEP MOST AREAS
(ESPECIALLY NEAR AND NORTH OF PHILLY) DRY THROUGH THIS PERIOD.
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, HIGH PRESSURE AND DRY CONDITIONS SHOULD
RETURN LATE IN THE WEEK INTO NEXT WEEKEND.
AVIATION /18Z MONDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY...VFR WITH MOSTLY CLEAR SKIES THIS AFTERNOON.
WEST WINDS AROUND 10-15 KT WITH GUSTS UP TO 20-25 KT. HIGH
CONFIDENCE.
TONIGHT...VFR. WINDS AROUND 10 KNOTS AND SHIFTING FROM WEST IN
THE EVENING TO NW OVERNIGHT WITH SOME HIGHER GUSTS OF 15-20
KNOTS POSSIBLE. HIGH CONFIDENCE.
OUTLOOK...
TUESDAY...VFR WITH GUSTY NORTHWEST WINDS AROUND 25 KT.
WEDNESDAY THROUGH FRIDAY...MOSTLY VFR.
MARINE
THE SMALL CRAFT ADVISORY ON THE ATLANTIC OCEAN WATERS HAS NOW
BEEN ALLOWED TO EXPIRE.
WINDS WILL CONTINUE TO GRADUALLY DIMINISH TO 10-20 KT THIS
AFTERNOON. SEAS AROUND 3-4 FEET. FAIR WEATHER.
WINDS RAMP UP AGAIN TONIGHT OUT OF THE NW WITH GUSTS OF 25 TO
30 KNOTS BY THE OVERNIGHT PERIOD. ADDITIONAL SCA'S WILL LIKELY
BE POSTED BY THIS AFTERNOON.
OUTLOOK...
TUESDAY 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
FOR TODAY, MIN RH VALUES ARE EXPECTED TO BE AROUND 45-60% ON
WITH WIND GUSTS UP TO 25 MPH. THE COMBINATION OF THE RHS NOT
GETTING TOO LOW PLUS THE RECENT RAIN WILL LIMIT FIRE WEATHER
CONCERNS FOR TODAY
A BIGGER CONCERN IS IN THE WAKE OF A SECONDARY COLD FRONT ON
TUESDAY. MIN RH VALUES OF 30 TO 40 PERCENT ARE LIKELY, AND
NORTHWEST WINDS ARE EXPECTED TO GUST 25 TO 35 MPH, WITH GUSTS UP
TO 40 MPH POSSIBLE IN HIGHER TERRAIN - ESPECIALLY ALONG RIDGES.
THE VERY DRY CONDITIONS CONTINUE ON WEDNESDAY, BUT WINDS SHOULD
BE CONSIDERABLY LIGHTER.
CLIMATE
RECORD STRETCH (CONSECUTIVE DAYS) WITHOUT MEASURABLE
PRECIPITATION:
FINAL
SITE RECORD RECORD DATES THRU 11/9
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
AC AIRPORT (ACY) 34 DAYS AUG-SEP 1995 38 DAYS
THESE STRETCHES HAVE ENDED WITH MEASURABLE PRECIPITATION BEING
RECORDED AT THESE STATIONS ON SUNDAY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...JOHNSON/MJL
NEAR TERM...DESILVA/FITZSIMMONS
SHORT TERM...JOHNSON/MJL
LONG TERM...JOHNSON/MJL
AVIATION...DESILVA/FITZSIMMONS/JOHNSON
MARINE...DESILVA/FITZSIMMONS/JOHNSON
FIRE WEATHER...
CLIMATE...
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