071
FXUS61 KPHI 131503
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1003 AM 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 TONIGHT/
AS OF 1000 AM, THE NEARBY 12Z RAOBS ALL SHOW A VERY DRY ENVIRONMENT
IN PLACE WITH PRECIPITABLE WATER VALUES BELOW 0.25 INCHES. THE AXIS
OF A MID TO UPPER LEVEL RIDGE IS APPROACHING OUR AREA TODAY, HOWEVER
A 250-300 MB JET IS PRODUCING SOME THIN CIRRUS UP NEAR 30,000 FEET
AGL WHICH IS CROSSING THE RIDGE AXIS. THIS CIRRUS IS NOT ANTICIPATED
TO AMOUNT TO MUCH AND THEREFORE A MAINLY SUNNY DAY IS FORECAST. THE
COLD NORTH TO NORTHEAST WIND HOWEVER OVER THE MILDER OCEAN WATERS IS
RESULTING IN NUMEROUS STRATOCUMULUS STREAKS JUST OFF THE SOUTHERN
NEW JERSEY AND DELAWARE COASTS. SOME OF THIS IS BRUSHING MAINLY THE
DELAWARE BEACHES. JUST MAINLY MINOR ADJUSTMENTS NEEDED TO THE HOURLY
TEMPERATURE, DEW POINT AND WIND GRIDS WITH THIS UPDATE.
OTHERWISE, SHORTWAVE RIDGING WILL BE THE DOMINANT FEATURE LEADING TO
DRY CONDITIONS. SEE THE FIRE WEATHER SECTION BELOW ABOUT
IMPLICATIONS FOR FIRE DANGER/SPREAD. LOW TEMPERATURES TONIGHT, WHICH
OUTSIDE OF THE URBAN CORRIDOR AND IMMEDIATE COAST, COULD BE THE
LOWEST TEMPERATURES WE HAVE SEEN SO FAR THIS FALL. THE LIGHT TO CALM
WINDS, DRY AIR, AND A MAINLY CLEAR SKY MUCH OF THE NIGHT WILL LEAD
TO EFFICIENT RADIATIONAL COOLING, ESPECIALLY IN THE PINE BARRENS,
RIVER VALLEYS, AND INTERIOR DELMARVA.
SHORT TERM /THURSDAY THROUGH FRIDAY/
A DECAYING TROUGH MOVES THROUGH THE CENTRAL US, WITH AN ASSOCIATED
AREA OF LOW PRESSURE MOVING TOWARDS THE GREAT LAKES. THIS SURFACE
LOW WILL TRANSFER ITS ENERGY TO A SECONDARY LOW DEVELOPING OVER
EASTERN NORTH CAROLINA. THIS SECONDARY LOW WILL PUSH SOUTHEAST OFF
THE MID-ATLANTIC COAST. GUIDANCE HAS TRENDED DRIER OVERALL AS THE
SECONDARY SURFACE LOW LOOKS TO DEVELOP FURTHER SOUTH THAN PREVIOUSLY
THOUGHT, WITH STRONG HIGH PRESSURE PASSING TO THE NORTH HAVING MORE
INFLUENCE. THE RESULT WILL BE A MAINLY DRY THURSDAY WITH INCREASING
CLOUDS AS THE SYSTEM APPROACHES. HIGHS WILL BE IN THE UPPER 40S/LOW
50S.
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 /15Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REST OF TODAY...VFR. NORTH TO NORTHEAST WINDS NEAR 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. 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
AS TO 1000 AM, THE SMALL CRAFT ADVISORY WAS ALLOWED TO EXPIRE FOR
THE LOWER DELAWARE BAY AS THE WINDS HAVE DIMINISHED BELOW 25 KNOTS.
WINDS SHOULD CONTINUE TO GRADUALLY DIMINISH TODAY, AND BY MID-
AFTERNOON WINDS SHOULD BE BELOW 25 KNOTS FOR ALL LOCATIONS.
ONCE WINDS DIMINISH, SEAS WILL REMAIN ELEVATED ESPECIALLY FOR AREAS
SOUTH OF THE MANASQUAN INLET. BASED ON THE LATEST GUIDANCE IT
APPEARS AS IF SEAS WILL REMAIN NEAR OR ABOVE 5 FEET THROUGH THE
NIGHT AND INTO THURSDAY.
OUTLOOK...
THURSDAY THROUGH 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
TODAY, NORTHEASTERLY WINDS WILL BE AROUND 10 MPH WITH A FEW GUSTS UP
TO 15 MPH. A VERY DRY AIRMASS WILL BE IN PLACE WITH MINIMUM RH
VALUES GENERALLY BETWEEN 20 TO 30 PERCENT, WITH THE EXCEPTION OF THE
IMMEDIATE COASTAL AREA. 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.
NOT EXPECTING ANY CONCERNS ON THURSDAY AS A WEAK SYSTEM
APPROACHES, BRINGING SOME MOISTURE AND MINIMUM RHS GENERALLY
BETWEEN 40-60% AND LIGHT WINDS.
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
THE COASTAL FLOOD ADVISORY WAS CANCELLED FOR CAPE MAY COUNTY,
NJ AND SUSSEX COUNTY, DE.
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/JOHNSON
SHORT TERM...HOEFLICH
LONG TERM...HOEFLICH
AVIATION...GORSE/HOEFLICH/JOHNSON
MARINE...GORSE/HOEFLICH/JOHNSON
FIRE WEATHER...PHI
TIDES/COASTAL FLOODING...PHI
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