837
FXUS61 KPHI 160218
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
918 PM EST FRI NOV 15 2024
SYNOPSIS
AS LOW PRESSURE MOVES FARTHER OUT TO SEA TONIGHT, HIGH PRESSURE
WILL GRADUALLY BUILD INTO OUR AREA LATE SATURDAY INTO SUNDAY. A
WEAK COLD FRONT MOVES THROUGH SUNDAY NIGHT INTO MONDAY FOLLOWED
BY WEAK HIGH PRESSURE TUESDAY. A POTENTIALLY STRONG UPPER LEVEL
SYSTEM WITH ASSOCIATED SURFACE LOW PRESSURE AND FRONTS SHOULD
ARRIVE DURING THE SECOND HALF OF NEXT WEEK.
NEAR TERM /THROUGH SATURDAY/
BROAD HIGH PRESSURE OVER THE CENTRAL U.S. WILL BUILD EAST TONIGHT
AND WILL BE CENTERED OVER THE GREAT LAKES AND OHIO VALLEY ON
SATURDAY.
THERE IS SOME SHORTWAVE ENERGY PASSING FROM NORTH TO SOUTH OVER
EASTERN PENNSYLVANIA PRODUCING SOME STRATUS OVER EXTREME WESTERN
PORTIONS OF THE AREA. THIS SHOULD PERSIST THROUGH THE EARLY
EVENING BEFORE BEGINNING TO ERODE OVERNIGHT. ELSEWHERE, SKIES
WILL REMAIN CLEAR THROUGHOUT THE REGION TONIGHT. LOWS TONIGHT
WILL DROP INTO THE LOW TO MID 30S FOR MOST OF NEW JERSEY AS WELL
AS THE LEHIGH VALLEY AND SOUTHERN POCONOS. FOR THE DELAWARE
VALLEY AND DELMARVA, LOWS TONIGHT WILL BE IN THE MID TO UPPER
30S. LOWS IN PHILADELPHIA AND ALONG THE COASTS WILL BE IN THE
LOW 40S. SATURDAY WILL FEATURE SUNNY SKIES WITH HIGHS IN THE
UPPER 50S TO LOW 60S, WHICH ARE ABOUT 5 TO 7 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR.
BRISK NORTHWEST WINDS WILL DEVELOP LATE SATURDAY MORNING AND WILL
PERSIST FOR MOST OF THE DAY, GENERALLY RANGING FROM 15 TO 20
MPH WITH 25 TO 30 MPH GUSTS. A RED FLAG WARNING WILL BE IN
EFFECT FOR SATURDAY FOR OUR NJ/PA COUNTIES (SEE FIRE WEATHER
SECTION BELOW FOR MORE DETAILS).
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/
A RIDGE ALOFT IS FORECAST TO APPROACH OUR REGION SATURDAY NIGHT
BEFORE SLIDING OVERHEAD SUNDAY THEN OFFSHORE SUNDAY NIGHT INTO
MONDAY. THIS TAKES SURFACE HIGH PRESSURE ACROSS OUR AREA LATE
SATURDAY NIGHT AND SUNDAY. THE APPROACH OF SURFACE HIGH PRESSURE
WILL RESULT IN WINDS DIMINISHING SATURDAY NIGHT INTO SUNDAY. GIVEN A
DRY AIR MASS AND A MOSTLY CLEAR SKY, TEMPERATURES WILL FALL QUICKLY
SATURDAY EVENING WITH LOW TEMPERATURES HOVERING AROUND FREEZING FOR
MOST (WARMER NEAR THE URBAN CORRIDOR AND ALONG THE COAST). THE
CENTER OF HIGH PRESSURE THEN SETTLES OFF TO OUR SOUTH SUNDAY
RESULTING IN A PLEASANT DAY. TEMPERATURES SUNDAY WILL BE SIMILAR OR
A TOUCH HIGHER COMPARED TO SATURDAY WHICH PUTS HIGH TEMPERATURES
ABOVE AVERAGE.
AS A LARGE UPPER-LEVEL TROUGH SWINGS ACROSS EASTERN CANADA SUNDAY
NIGHT INTO MONDAY, A STRONG SHORTWAVE LOOKS TO GLANCE OUR REGION.
THIS SHOULD TOSS SOME CLOUDINESS OUR WAY SUNDAY AFTERNOON AND NIGHT.
THIS SAME FEATURE WILL PULL A WEAK COLD FRONT INTO AND ACROSS OUR
AREA SUNDAY NIGHT INTO MONDAY, HOWEVER MOISTURE IS RATHER LIMITED
AND THEREFORE NO PRECIPITATION IS EXPECTED. GIVEN MORE CLOUDINESS
SUNDAY NIGHT, THE TEMPERATURES ARE NOT EXPECTED TO BE AS COLD WITH
LOWS MAINLY IN THE UPPER 30S TO LOW 40S.
AS WE GO THROUGH MONDAY, THE WEAK COLD FRONT SHOULD BE SHIFTING
OFFSHORE DURING THE MORNING HOWEVER THERE IS NO REAL TEMPERATURE
CHANGE BEHIND IT (THE FRONT LOOKS TO BE MORE OF A WIND SHIFT). AS A
RIDGE ALOFT STARTS TO APPROACH LATER MONDAY, HEIGHTS RISE AND THIS
WILL TRANSLATE TO A WARMER AFTERNOON. HIGH TEMPERATURES ARE FORECAST
TO BE WELL INTO THE 60S FOR MUCH OF THE AREA. ANY CLOUDINESS SHOULD
DECREASE DURING MONDAY AS DRIER AIR WORKS IN ONCE AGAIN ALONG WITH
SOME INCREASED SUBSIDENCE.
LONG TERM /TUESDAY THROUGH FRIDAY/
SUMMARY...A PATTERN CHANGE SHOULD BRING INCREASING CHANCES FOR
PRECIPITATION AND ALSO TURNING COOLER.
SYNOPTIC OVERVIEW...A STRONG UPPER-LEVEL TROUGH IS FORECAST TO SHIFT
OUT OF THE WEST AND ACROSS THE PLAINS DURING TUESDAY. A TRAILING
STRONG SHORTWAVE IS FORECAST TO CARVE THIS TROUGH OUT MORE AS IT
SHIFTS EASTWARD THROUGH THE WEEKEND AND EVENTUALLY SETTLES IN ACROSS
THE EAST. PRIOR TO ITS ARRIVAL, A RIDGE ALOFT WILL RESULT IN
TEMPERATURES ABOVE AVERAGE BEFORE TRENDING NEAR OR BELOW AVERAGE BY
THE END OF THE WEEK. AT THE SURFACE, LOW PRESSURE SLIDING ACROSS THE
GREAT LAKES WILL LIFT A WARM FRONT INTO PARTS OF OUR AREA WEDNESDAY,
THEN AN OCCLUDED FRONT SHOULD MOVE THROUGH THURSDAY INTO FRIDAY AS
LOW PRESSURE MAY DEVELOP ALONG THE TRIPLE POINT.
FOR TUESDAY AND WEDNESDAY...AS A RIDGE AXIS ALOFT IS ACROSS OUR AREA
TUESDAY, WEAK SURFACE HIGH PRESSURE EXTENDS ACROSS OUR AREA.
MEANWHILE, A STRENGTHENING UPPER-LEVEL TROUGH IS FORECAST TO BE
SHIFTING ACROSS THE PLAINS AND MIDWEST REGIONS WHICH SUPPORTS
SURFACE LOW PRESSURE ACROSS THE MIDWEST INTO THE UPPER GREAT LAKES.
A WARM FRONT IS FORECAST TO EXTEND EAST-SOUTHEAST FROM THIS LOW AND
BE INITIALLY TO OUR SOUTH. AS THIS ENTIRE SYSTEM SHIFTS EASTWARD,
LOW TO MID LEVEL WARM AIR ADVECTION WILL INCREASE INTO OUR AREA AND
THE WARM FRONT SHOULD START TO LIFT NORTHWARD. AS A RESULT, CLOUDS
SHOULD INCREASE DURING TUESDAY AND THE SURFACE FLOW WILL WEAKEN AND
START TO TURN MORE FROM A SOUTHERLY DIRECTION. AS WE GO THROUGH
WEDNESDAY, THE PARENT SURFACE LOW IN THE VICINITY OF THE GREAT LAKES
MAY END UP OCCLUDING AND THIS STARTS TO ARRIVE INTO OUR AREA LATE
WEDNESDAY. A NEW SURFACE LOW MAY DEVELOP ON THE TRIPLE POINT AND THE
NORTHERN EXTEND OF THE WARMTH WILL DEPEND ON THE NORTHWARD MOVEMENT
OF THE WARM FRONT/SECTOR. SOME AREAS WEDNESDAY HOWEVER COULD WARM
WELL INTO THE 60S TO NEAR 70 DEGREES ESPECIALLY ACROSS THE COASTAL
PLAIN. AS SOME INITIAL ISENTROPIC LIFT AHEAD OF THE NORTHWARD BOUND
WARM FRONT ARRIVES, SOME RAIN CHANCES START TO INCREASE LATER
WEDNESDAY AND ESPECIALLY WEDNESDAY NIGHT. GIVEN THE UNCERTAINTY WITH
TIMING AND TRACK OF THE SURFACE LOW, KEPT POPS NO HIGHER THAN THE
CHANCE RANGE.
FOR THURSDAY AND FRIDAY...THE AFOREMENTIONED UPPER-LEVEL TROUGH IS
FORECAST TO AMPLIFY ACROSS THE EAST DURING THIS TIME FRAME. AS
MENTIONED EARLIER THE INITIAL SURFACE LOW MAY OCCLUDE WHILE A NEW
SURFACE LOW DEVELOPS AT THE TRIPLE POINT AND MAY TRACK ACROSS PARTS
OF OUR AREA THURSDAY INTO FRIDAY. SOME OF MODEL GUIDANCE AND
ENSEMBLES OFFER A STRONGER UPPER-LEVEL TROUGH/LOW AND THEREFORE ARE
SLOWER WITH THE PROGRESS OF THE SURFACE FEATURES. AGAIN GIVEN THE
UNCERTAINTY IN STRENGTH AND OVERALL TIMING, KEPT POPS NO HIGHER THAN
THE CHANCE RANGE. THE OVERALL SYNOPTIC SETUP HOWEVER WOULD FAVOR A
MORE WIDESPREAD PRECIPITATION EVENT, HOWEVER HOW MUCH IS STILL NOT
CERTAIN. WITH THE ARRIVAL OF THIS SYSTEM, TEMPERATURES ARE FORECAST
TO BE COOLER AND NEAR TO POTENTIALLY BELOW AVERAGE.
AVIATION /02Z SATURDAY THROUGH WEDNESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR FOR ALL TERMINALS EXCEPT KRDG WITH MAY ENCOUNTER
MVFR CIGS, ERODING AFTER 05Z. NW WINDS AROUND 10 KT. HIGH
CONFIDENCE.
SATURDAY...VFR. NW WINDS 15 TO 20 KT WITH 25 TO 30 KT GUSTS
AFTER 15Z. HIGH CONFIDENCE.
OUTLOOK...
SATURDAY NIGHT...VFR WITH A DIMINISHING WIND.
SUNDAY THROUGH TUESDAY...VFR.
WEDNESDAY...SUB-VFR CONDITIONS AND SOME RAIN POSSIBLE.
MARINE
A SMALL CRAFT ADVISORY IS NOW IN EFFECT FOR ALL ATLANTIC OCEAN
COASTAL WATERS AND THE ENTIRE DELAWARE BAY THROUGH SATURDAY.
NORTHWEST WINDS WILL INCREASE TO 15 TO 20 KT WITH 25 TO 30 KT GUSTS
LATE TONIGHT AND SATURDAY. SEAS ON THE OCEAN WILL BUILD TO 4 TO 6
FEET. FAIR WEATHER OTHERWISE.
OUTLOOK...
SATURDAY NIGHT...A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL WATERS
THROUGH ABOUT THE FIRST HALF OF THE NIGHT.
SUNDAY THROUGH TUESDAY...A PERIOD OF NEAR SMALL CRAFT ADVISORY
CONDITIONS (WIND GUSTS) POSSIBLE MONDAY NIGHT, OTHERWISE THE
CONDITIONS ARE ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA.
WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS MAY DEVELOP.
FIRE WEATHER
A RED FLAG WARNING IS NOW IN EFFECT FOR PENNSYLVANIA AND NEW JERSEY
FOR SATURDAY. WITH CONTINUED VERY DRY CONDITIONS, MINRH VALUES
WILL GENERALLY BE BETWEEN 25 AND 30 PERCENT, AND NORTHWEST WINDS
WILL INCREASE TO 15 TO 20 MPH WITH 25 TO 30 MPH GUSTS STARTING
LATE SATURDAY MORNING.
FOR THE EASTERN SHORES OF MARYLAND AND DELAWARE, ALTHOUGH THERE WILL
BE THE GUSTY WINDS, THERE WAS LESS THAN 1/10 INCH RAINFALL THROUGH
FRIDAY MORNING. IN ADDITION, MINRH VALUES ON SATURDAY WILL BE
BETWEEN 40 AND 50 PERCENT. AS A RESULT, A SPECIAL WEATHER STATEMENT
FOR THE THREAT FOR THE RAPID SPREAD OF ANY FIRES THAT DEVELOP WILL
BE ISSUED FOR SATURDAY.
FOR SUNDAY, MINIMUM RH VALUES ARE FORECAST TO BE 30-45 PERCENT
AND THE WINDS WILL BE MUCH LESS COMPARED TO SATURDAY (NORTHWEST
WINDS AROUND 10 MPH). DESPITE THE CONTINUED VERY DRY SURFACE
CONDITIONS, THE LIGHTER WINDS WILL RESULT IN A MUCH LOWER RISK
FOR RAPID FIRE SPREAD.
TIDES/COASTAL FLOODING
A COMBINATION OF PERSISTENT SHORE PARALLEL WINDS AND HIGH
ASTRONOMICAL TIDES WITH A FULL MOON TODAY WILL LEAD TO COASTAL
FLOODING CONTINUING INTO THE WEEKEND. WIDESPREAD MINOR TIDAL
FLOODING OCCURRED THIS MORNING ALONG THE ATLANTIC OCEAN COASTS
OF NEW JERSEY AND DELAWARE, INCLUDING A FEW GAUGES BRIEFLY
TOUCHING MODERATE FLOOD STAGE.
THE COASTAL FLOOD ADVISORY REMAINS IN EFFECT FOR THE NEW JERSEY
AND DELAWARE COAST AND WITHIN DELAWARE BAY THROUGH SATURDAY
MORNING'S HIGH TIDE. ASTRONOMICAL TIDES WILL DECLINE THROUGH THE
WEEKEND, BUT STILL EXPECTING WIDESPREAD MINOR TIDAL FLOODING
ALONG THE ATLANTIC OCEAN COAST AND WITHIN DELAWARE BAY, HENCE
THE EXTENSION TO THE COASTAL FLOOD ADVISORY IN THESE LOCATIONS
THROUGH NOON SATURDAY. NO ADDITIONAL MODERATE FLOODING IS
EXPECTED WITH SUBSEQUENT HIGH TIDES.
WITH THIS MORNING'S HIGH TIDE, TIDAL PILING INTO THE DELAWARE
BAY WILL RESULT IN WIDESPREAD MINOR TIDAL FLOODING OCCURING
ALONG THE TIDAL DELAWARE RIVER. THE COASTAL FLOOD ADVISORY FOR
THIS MORNING REMAINS UNCHANGED FOR THIS AREA.
WIDESPREAD COASTAL FLOODING IS NOT EXPECTED TO OCCUR ALONG THE
CHESAPEAKE BAY IN THE EASTERN SHORE OF MARYLAND, HOWEVER CANNOT
COMPLETELY RULE OUT THE GAUGE AT TOLCHESTER BEACH OR CLAIBORNE
BRIEFLY TOUCHING MINOR FLOOD STAGE WITH THIS AFTERNOON'S HIGH
TIDE.
PHI WATCHES/WARNINGS/ADVISORIES
PA...RED FLAG WARNING FROM 7 AM TO 6 PM EST SATURDAY FOR PAZ054-055-
060>062-070-071-101>106.
NJ...COASTAL FLOOD ADVISORY UNTIL NOON EST SATURDAY FOR NJZ012>014-
020>027.
RED FLAG WARNING FROM 7 AM TO 6 PM EST SATURDAY FOR NJZ001-
007>010-012>027.
DE...COASTAL FLOOD ADVISORY UNTIL NOON EST SATURDAY FOR DEZ002>004.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST SATURDAY FOR ANZ430-431-
450.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR ANZ451>455.
SYNOPSIS...GORSE
NEAR TERM...DESILVA/MPS
SHORT TERM...GORSE/HOEFLICH
LONG TERM...GORSE
AVIATION...DESILVA/GORSE/MPS
MARINE...DESILVA/GORSE/MPS
FIRE WEATHER...WFO PHI
TIDES/COASTAL FLOODING...WFO PHI
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