965
FXUS61 KPHI 131814
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
114 PM EST WED NOV 13 2024
SYNOPSIS
HIGH PRESSURE REMAINS IN CONTROL THROUGH THURSDAY. A WEAK AREA OF
LOW PRESSURE APPROACHES ON THURSDAY NIGHT, WITH A COASTAL LOW
DEVELOPING WELL TO THE SOUTH. THE COASTAL LOW PUSHES OFF THE MID-
ATLANTIC COAST ON FRIDAY WITH HIGH PRESSURE BUILDING IN FOR THE
WEEKEND. ANOTHER FRONTAL SYSTEM APPROACHES TO START NEXT WEEK BEFORE
HIGH PRESSURE MOVES BACK IN FOR THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH THURSDAY/
A NARROWING MID TO UPPER LEVEL RIDGE WILL CROSS OUR AREA LATER
TONIGHT BEFORE WEAKENING DURING THURSDAY. SOME BLOCKING SETS UP ON
THE SYNOPTIC SCALE THROUGH THURSDAY, WITH CHILLY AIR REMAINING IN
PLACE.
AN APPROACHING UPPER-LEVEL TROUGH SHOULD CLOSE OFF WHILE ANOTHER
CLOSED LOW RETROGRADES, SLIDES NORTHWEST OR WEST, TO NEAR NOVA
SCOTIA CANADA THROUGH THURSDAY. BOTH OF THESE SUPPORT SURFACE LOW
PRESSURES WITH THE FIRST DEVELOPING OFF THE SOUTHEAST VIRGINIA/NORTH
CAROLINA COAST WHILE THE LATTER PUTS LOW PRESSURE CLOSER TO THE NOVA
SCOTIA AREA. GIVEN THE RETROGRADING TO OUR NORTHEAST, SURFACE HIGH
PRESSURE WHILE IT WEAKENS OVER OUR AREA DOES STILL REMAIN OVERHEAD
FOR MUCH OF OUR REGION. WHILE WE NEED THE RAIN, THIS PATTERN OFFERS
DECREASING CHANCES DUE TO THE INCOMING SYSTEM HITTING A BRICK WALL
AND BEING DEFLECTED TO OUR SOUTH.
REGARDING MORE OF THE DETAILS, STRONG SURFACE HIGH PRESSURE CENTERED
WELL TO OUR NORTH THIS AFTERNOON AND TONIGHT WILL SHIFT NORTHWARD
AND WEAKEN WITH TIME DURING THURSDAY. THIS WILL RESULT IN LIGHT TO
NEAR CALM WINDS TONIGHT AND WITH A VERY DRY AIR MASS THE
TEMPERATURES WILL DROP QUICKLY THIS EVENING. SOME CIRRUS SHOULD
CONTINUE TO CREST THE RIDGE AXIS AS IT CROSSES OUR AREA, HOWEVER
THIS SHOULD NOT SIGNIFICANTLY IMPACT THE RADIATIONAL COOLING
TONIGHT. AS A RESULT, MANY AREAS ARE FORECAST TO DROP BELOW FREEZING
ONCE AGAIN OVERNIGHT. IT WILL BE THE WARMEST ALONG THE COAST DUE TO
A CONTINUED NORTHEASTERLY WIND.
AS WE GO THROUGH THURSDAY, CLOUDS WILL QUICKLY INCREASE WITH THIS
INITIALLY BEING HIGH TO MID LEVEL CLOUDS AND THEN SOME LOWER CLOUDS
MAY ALSO DEVELOP WITHIN THE EASTERLY LOW-LEVEL FLOW. THE AIR MASS
WILL BE UNDERGOING SOME MOISTENING AND THIS LOOKS TO BE THE MOST
PRONOUNCED ACROSS OUR SOUTHERN ZONES WHERE SURFACE HIGH PRESSURE
WEAKENS THE MOST. WHILE SOME SPRINKLES OR A FEW LIGHT SHOWERS CANNOT
BE RULED OUT ACROSS OUR EASTERN MARYLAND SHORE ZONES NORTH TO
WESTERN CHESTER AND WESTERN BERKS COUNTIES LATER IN THE AFTERNOON,
IT LOOKS LIKE THE DRY AIR WILL WIN OUT AND THEREFORE LOWERED THE
POPS SOME MORE FOR THE LATE AFTERNOON HOURS. THE INCREASED
CLOUDINESS WILL RESULT IN ANOTHER CHILLY DAY WITH HIGHS ONLY IN THE
40S TO LOWER 50S WITH A MOSTLY LIGHT NORTHEAST OR EAST BREEZE.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/
SOME SHOWERS ARE POSSIBLE THURSDAY NIGHT, ESPECIALLY SOUTH OF
PHILADELPHIA. RAINFALL AMOUNTS WERE BASICALLY CUT IN HALF WITH
THIS UPDATE. THE HIGHEST AMOUNTS WILL BE OVER LOWER DELMARVA,
THOUGH ONLY UP TO A QUARTER OF AN INCH AT MOST. MOST AREAS NORTH
OF THE PHILADELPHIA METRO AREA WILL EITHER SEE A FEW DROPS OR
NOTHING AT ALL. IF PRECIPITATION WERE TO MAKE IT FAR ENOUGH
NORTH TO REACH THE HIGHER ELEVATIONS, A FEW SNOWFLAKES CAN'T BE
RULED OUT. OVERALL, NOT AN OVERLY IMPACTFUL EVENT AND NOTHING TO
PUT A DENT IN OUR CURRENT DROUGHT. LOWS ON THURSDAY NIGHT WILL
RANGE FROM THE LOW TO MID 30S NORTH AND WEST OF THE I-95
CORRIDOR TO UPPER 30S/LOW 40S ALONG AND SOUTH OF I-95.
EXPECT IMPROVING CONDITIONS ON FRIDAY AS SKIES CLEAR OUT WITH
SURFACE LOW PUSHING OFFSHORE AND HIGH PRESSURE MOVING IN. ANY
LINGERING SHOWERS OVER SOUTHERN DELAWARE MOVE OUT BY THE LATE
MORNING WITH SOME SUN EXPECTED FOR THE AFTERNOON. TEMPERATURES WILL
GENERALLY BE IN THE MID 50S.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
UPPER LEVEL RIDGING BUILDS IN FOR THE WEEKEND WITH AN EXPANSIVE AREA
OF HIGH PRESSURE MOVING IN FROM THE WEST. THIS WILL RESULT IN A DRY
WEEKEND WITH MODERATING TEMPERATURES. HIGHS WILL GET INTO THE 60S
WITH A STEADY NORTHWEST FLOW. OVERNIGHT LOWS FRIDAY AND SATURDAY
NIGHT WILL BE IN THE MID TO UPPER 30S. THE RETURN OF DRY NORTHWEST
FLOW WILL BRING ANOTHER PERIOD FOR POTENTIAL FIRE WEATHER
CONDITIONS, ESPECIALLY ON SATURDAY, WHERE WIND GUSTS BETWEEN 20-30
MPH ARE POSSIBLE WITH A TIGHT GRADIENT IN PLACE DUE TO THE INCOMING
HIGH AND AN AREA OF LOW PRESSURE NEAR THE CANADIAN MARITIMES. WINDS
WILL BE LOWER ON SUNDAY WITH HIGH MOVING CLOSER AND THE GRADIENT
WEAKENING BUT RHS WILL BE SIMILAR TO SATURDAY (BETWEEN 25-35% DURING
THE AFTERNOON).
THE RIDGE BREAKS DOWN ON MONDAY WITH A SHORTWAVE IMPINGING IN FROM
CANADA. AT THE SURFACE, A COLD FRONT LOOKS TO COME THROUGH BUT THE
FRONT LOOKS MOISTURE STARVED AT THE MOMENT. RIDGING AT THE SURFACE
AND ALOFT WILL BUILD IN FOR THE MIDDLE OF THE NEXT WEEK AS THE LONG
TERM PERIOD LOOKS RATHER DRY. THE FRONT DOESN'T LOOK TO LOWER
TEMPERATURES MUCH, AND ABOVE NORMAL TEMPERATURES SHOULD CONTINUE
INTO THE MIDDLE OF NEXT WEEK.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REST OF THIS AFTERNOON...VFR. NORTH TO NORTHEAST WINDS LESS THAN 10
KNOTS. MODERATE CONFIDENCE
TONIGHT...VFR WITH INCREASING MAINLY HIGH CLOUDS. NORTHEAST WINDS
AROUND 5 KNOTS TO LOCALLY LIGHT AND VARIABLE. HIGH CONFIDENCE.
THURSDAY...VFR CEILINGS. NORTHEAST TO EAST-NORTHEAST WINDS 5-10
KNOTS. MODERATE CONFIDENCE.
OUTLOOK...
THURSDAY NIGHT...PRIMARILY VFR THOUGH SOME MVFR CEILINGS POSSIBLE AS
SCATTERED SHOWERS MOVE IN. HIGHEST CHANCE FOR SHOWERS EXPECTED FROM
KPHL ON SOUTH.
FRIDAY THROUGH SUNDAY...VFR. GUSTY NORTHWEST WINDS POSSIBLE ON
SATURDAY WITH GUSTS UP TO 25 KT ANTICIPATED.
MARINE
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR MOST OF THE NEW JERSEY
AND DELAWARE ATLANTIC COASTAL WATERS THROUGH AT LEAST THURSDAY
MOSTLY DUE TO ELEVATED SEAS. THE NORTH TO NORTHEASTERLY WIND GUSTS
SHOULD BE UNDER 25 KNOTS, HOWEVER THIS FLOW WILL KEEP THE SEA
HEIGHTS ELEVATED. THE CONDITIONS ARE ANTICIPATED TO STAY BELOW SMALL
CRAFT ADVISORY CRITERIA ON DELAWARE BAY THROUGH THURSDAY.
OUTLOOK...
THURSDAY NIGHT...THE SMALL CRAFT ADVISORY WAS EXTENDED FOR
COASTAL WATERS SOUTH OF MANASQUAN INLET AS SEAS WILL BE AROUND 5
FEET. NORTH OF MANASQUAN INLET AND ON DELAWARE BAY, NO MARINE
HEADLINES EXPECTED.
FRIDAY...MAY GET A BRIEF PERIOD OF SUB-SCA CONDITIONS THOUGH SEAS
COULD REMAIN NEAR 5 FEET, REQUIRING AN EXTENSION TO THE SMALL CRAFT
ADVISORY.
FRIDAY NIGHT THROUGH SATURDAY...SCA CONDITIONS EXPECTED
(80-90%) WITH NORTHWEST WINDS 25-30 KT AND SEAS AROUND 4 TO 6
FEET. .
FIRE WEATHER
NORTH TO NORTHEAST WINDS NEAR 10 MPH THIS AFTERNOON BEFORE
DIMINISHING TOWARD EARLY EVENING. A VERY DRY AIRMASS IS IN PLACE
WITH MINIMUM RH VALUES GENERALLY BETWEEN 20-35 PERCENT. WHILE THE
WINDS ARE MUCH LIGHTER COMPARED TO YESTERDAY, THE CONDITIONS
CONTINUE TO BE VERY DRY AND THEREFORE A SPECIAL WEATHER STATEMENT
CONTINUES FOR OUR DELMARVA ZONES AND ALSO FOR NEW JERSEY BASED ON
FEEDBACK FROM OUR STATE FIRE PARTNERS.
FOR THURSDAY, THE LOW-LEVEL MOISTURE INCREASES ESPECIALLY ACROSS
SOUTHERN NEW JERSEY, DELMARVA INTO SOUTHEASTERN PENNSYLVANIA AS A
SYSTEM APPROACHES FROM THE WEST. MINIMUM RHS ARE FORECAST TO
GENERALLY BETWEEN 35-60 PERCENT AND LIGHT NORTHEAST TO EAST-
NORTHEAST WINDS. GIVEN THIS, NOT EXPECTING ANY CONCERNS REGARDING
WILDFIRE SPREAD.
ATTENTION TURNS TO THE FRIDAY-SUNDAY PERIOD AS ANOTHER PERIOD OF
VERY DRY CONDITIONS ARE EXPECTED WITH MINIMUM RH VALUES
CURRENTLY FORECAST TO BE IN THE 25-35% RANGE. ELEVATED CONCERN
FOR SATURDAY AS WINDS WILL BE GUSTING BETWEEN 20-30 MPH OUT OF
THE NORTHWEST. WINDS WILL BE LIGHTER ON FRIDAY AND SUNDAY.
TIDES/COASTAL FLOODING
CONFIDENCE HAS INCREASED THAT A COMBINATION OF PERSISTENT SHORE
PARALLEL WINDS AND INCREASING ASTRONOMICAL TIDES WITH A FULL
MOON ON FRIDAY LOOK TO LEAD TO COASTAL FLOODING FOR THE BACK
HALF OF THE WEEK. WIDESPREAD MINOR TIDAL FLOODING IS EXPECTED
ALONG THE ATLANTIC OCEAN COASTS OF NEW JERSEY AND DELAWARE AND
THE ASSOCIATED BACKBAYS AS WELL AS WITHIN DELAWARE BAY BEGINNING
WITH THE THURSDAY MORNING HIGH TIDE. THE THREAT FOR MODERATE
TIDAL FLOODING HAS DECREASED BUT MADE NO CHANGE TO THE COASTAL
FLOOD WATCH FOR NOW AS THE POTENTIAL STILL REMAINS. HOWEVER,
THINKING THAT THIS IS MORE OF A HIGH-END MINOR EVENT.
BY THURSDAY AND INTO FRIDAY, TIDAL PILING INTO THE LOWER DELAWARE
BAY LOOKS TO RESULT IN MINOR TIDAL FLOODING OCCURING FURTHER
NORTH, ALONG THE SHORES OF THE UPPER DELAWARE BAY AS WELL AS THE
TIDAL DELAWARE RIVER.
COASTAL FLOODING IS NOT EXPECTED TO OCCUR ALONG THE CHESAPEAKE
BAY IN THE EASTERN SHORE OF MARYLAND.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING
FOR NJZ012>014-020-022>027.
DE...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING
FOR DEZ002>004.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ451>455.
SYNOPSIS...HOEFLICH
NEAR TERM...GORSE
SHORT TERM...HOEFLICH
LONG TERM...HOEFLICH
AVIATION...GORSE/HOEFLICH
MARINE...GORSE/HOEFLICH
FIRE WEATHER...PHI
TIDES/COASTAL FLOODING...PHI
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