528
FXUS61 KPHI 182016
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
316 PM EST MON NOV 18 2024
SYNOPSIS
A WEAK COLD FRONT WILL SETTLE TO OUR SOUTH TONIGHT, THEN APPROACH
AS A WARM FRONT LATER TUESDAY AND TUESDAY NIGHT. LOW PRESSURE
AND AN ASSOCIATED STRONG FRONT CROSSES OUR REGION WEDNESDAY
NIGHT INTO THURSDAY WITH SOME MUCH NEEDED RAIN. AN AREA OF LOW
PRESSURE SLOWLY MOVES ACROSS THE NORTHEAST THURSDAY AND FRIDAY
WITH MUCH COLDER AIR, THEN IT MOVES INTO THE CANADIAN MARITIMES
OVER THE WEEKEND. HIGH PRESSURE THEN ARRIVES FOR LATER SUNDAY
AND ESPECIALLY MONDAY.
NEAR TERM /THROUGH TUESDAY/
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT, FOLLOWING A
WEAK COLD FRONT, AND PERSIST THROUGH TUESDAY. IN ADDITION, A
WARM FRONT WILL APPROACH THE REGION FROM THE SOUTHWEST ON
TUESDAY. AS A RESULT OF HIGH PRESSURE, FAIR CONDITIONS ARE
EXPECTED THROUGH THE OVERNIGHT WITH JUST SOME HIGH CLOUDS. MORE
CLOUDINESS IS EXPECTED TOMORROW WITH A MID-LAYER DECK WORKING
INTO THE AREA.
THE GUSTY WINDS WE'RE EXPERIENCING THIS AFTERNOON WILL DIMINISH
AFTER SUNSET. WINDS WILL THEN BE LIGHT THROUGH TOMORROW.
LOWS TONIGHT WILL DROP INTO THE MID 30S TO LOW 40S MOST AREAS. HIGHS
ON TUESDAY WILL RANGE FROM THE MID 50S TO MID 60S.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/
A PATTERN CHANGE IS FORECAST TO TAKE PLACE WITH SOME MUCH NEEDED
RAIN EXPECTED.
A SIGNIFICANT UPPER-LEVEL TROUGH IS FORECAST TO CLOSE OFF ACROSS THE
MIDWEST AND NORTHERN PLAINS INTO WEDNESDAY AS IT SHIFTS SOUTHEAST
AND EASTWARD. THIS CLOSED LOW IS FORECAST TO SETTLE ACROSS THE MID-
ATLANTIC REGION WEDNESDAY NIGHT AND THURSDAY.
WEAK HIGH PRESSURE SHIFTS TO OUR EAST TO START TUESDAY NIGHT AND A
WARM FRONT WILL APPROACH FROM THE SOUTHWEST. SOME WEAK SHORTWAVE
ENERGY ALONG WITH WARM AIR ADVECTION MAY PROVIDE JUST ENOUGH LIFT
FOR A FEW SHOWERS ESPECIALLY ACROSS OUR SOUTHERN AREAS, BUT OVERALL
MOSTLY JUST CLOUD COVER. LOW TEMPERATURES WILL BE MOSTLY IN THE 40S
ACROSS THE AREA.
AS WE GO THROUGH WEDNESDAY AND THURSDAY, A SIGNIFICANT CHANGE IN THE
PATTERN EVOLVES AS THE AFOREMENTIONED CLOSED LOW ARRIVES WEDNESDAY
NIGHT. WHILE SOME SHOWERS CANNOT BE RULED OUT DURING THE DAY
WEDNESDAY AS A WARM FRONT TRIES TO LIFT NORTHWARD, THE BULK OF THE
PRECIPITATION IS EXPECTED AT NIGHT. THE INCOMING SYSTEM LOOKS TO
UNDERGO OCCLUSION AND THEREFORE AN OCCLUDED FRONT ARRIVES WEDNESDAY
NIGHT. A NEW SURFACE LOW MAY DEVELOP ALONG THE TRIPLE POINT AS IT
LIFTS ACROSS OUR AREA WITH THE INITIAL LOW HANGING BACK OVER THE
GREAT LAKES. IT WILL STILL BE MILD WEDNESDAY AHEAD OF THIS SYSTEM
WITH MORE CLOUDS. AS THE CLOSED LOW ARRIVES LATER WEDNESDAY NIGHT,
STRONG SHORTWAVE ENERGY AND FORCING FOR ASCENT SHOULD RESULT IN AN
EXPANDING AREA OF SHOWERS OR EVEN A PERIOD OF RAIN FROM ABOUT WEST-
SOUTHWEST TO EAST-NORTHEAST. SOME OF THIS COULD BE ON THE HEAVIER
SIDE, ESPECIALLY WITH A PERIOD OF MORE FOCUSED ASCENT. THE
INSTABILITY LOOKS TO BE LIMITED AND THEREFORE NO THUNDER INCLUDED IN
THE FORECAST. ACROSS OUR ENTIRE AREA, RAINFALL AMOUNTS LOOK TO BE
BETWEEN 0.30-0.80 INCHES, WITH POTENTIALLY SOME HIGHER AMOUNTS (AS
MUCH AS 1.00-1.25 INCHES) ACROSS OUR NORTHERN AREAS WHERE THE
FORCING FOR ASCENT MAY FURTHER STRENGTHEN FOR A TIME. THIS WILL NOT
BE A DROUGHT BUSTER, HOWEVER IT IS MUCH NEEDED RAIN. AS THE OCCLUDED
FRONT MOVES ACROSS OUR AREA, A BURST OF COLD AIR ADVECTION AND
PRESSURE RISES MAY RESULT IN A PERIOD OF GUSTY WINDS AS THEY
ABRUPTLY SHIFT FROM SOUTHERLY TO WEST AND NORTHWEST OVERNIGHT
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
WHILE THE SURFACE SYSTEMS WILL BE LIFTING TO OUR EAST AND NORTH
DURING THE DAY THURSDAY, PLENTY OF CYCLONIC FLOW WITH THE CLOSED LOW
IN PLACE WILL RESULT IN COLDER AIR AND THE CHANCE FOR SOME
INSTABILITY SHOWERS THROUGH THE DAY. THE CHANCES LOOK TO BE THE
HIGHEST ACROSS OUR NORTHWEST ZONES WHERE EVEN SOME WET SNOW COULD
MIX IN ACROSS THE POCONOS, WITH LESS INTO THE COASTAL PLAIN AS SOME
ADDED DRYING MAY LIMIT THE SHOWERS. A TIGHTENED PRESSURE GRADIENT
EVOLVING FROM THE SYNOPTIC SETUP WILL RESULT IN A GUSTY WEST TO
NORTHWEST WIND DURING THURSDAY WHICH MAY DIMINISH SOME AT NIGHT. AS
THE COLDER AIR DEEPENS THURSDAY NIGHT, SOME SNOW SHOWERS CANNOT BE
RULED OUT ACROSS PORTIONS OF THE POCONOS ESPECIALLY.
LONG TERM /FRIDAY THROUGH MONDAY/
SUMMARY...COLDER AIR WITH TEMPERATURES AT OR BELOW AVERAGE, WHICH
MAY THEN BECOME A LITTLE ABOVE AVERAGE EARLY NEXT WEEK. SOME SHOWER
POTENTIAL MOSTLY FRIDAY INTO SATURDAY.
SYNOPTIC OVERVIEW...A STRONG CLOSED LOW IS FORECAST TO BE GRADUALLY
EXITING THE EAST FRIDAY INTO SATURDAY, HOWEVER SOME CYCLONIC FLOW
REMAINS IN PLACE THROUGH THE WEEKEND. THE FLOW ALOFT MAY THEN BECOME
MORE ZONAL INTO EARLY NEXT WEEK. AT THE SURFACE, LOW PRESSURE
CENTERED ACROSS NEW ENGLAND IS FORECAST TO SHIFT NORTHEASTWARD AND
LIFT UP ACROSS THE CANADIAN MARITIMES OVER THE WEEKEND. A TROUGH OR
SECONDARY COLD FRONT MAY MOVE THROUGH LATER SATURDAY, THEN HIGH
PRESSURE BUILDS IN LATER SUNDAY AND ESPECIALLY MONDAY.
FOR FRIDAY...AN UNSETTLED PATTERN IS FORECAST TO BE IN PLACE DUE TO
A STRONG CLOSED LOW ACROSS MUCH OF THE EAST. THE CENTER OF THIS IS
FORECAST TO BE SHIFTING TO OUR EAST DURING FRIDAY, TAKING THE CORE
OF THE COLD AIR ALOFT WITH IT. PLENTY OF CYCLONIC FLOW ALOFT SHOULD
MAINTAIN A DECENT AMOUNT OF CLOUDINESS WITH THE COLDER ALOFT, AND
SOME SHOWERS CANNOT BE RULED OUT (EVEN SOME SNOW SHOWERS POSSIBLE IN
THE HIGHER ELEVATIONS OF MAINLY THE POCONOS). HIGH TEMPERATURES ARE
FORECAST TO NOT GET OUT OF THE 40S, AND WITH A TIGHTENED PRESSURE
GRADIENT IN PLACE A GUSTY NORTHWESTERLY BREEZE IS FORECAST AND THIS
WILL RESULT IN LOWERED WIND CHILL VALUES.
FOR SATURDAY AND SUNDAY...THE CYCLONIC FLOW IS FORECAST TO GRADUALLY
WEAKEN AS THE CLOSED LOW LIFTS FARTHER UP ACROSS THE CANADIAN
MARITIMES REGION. THIS WILL RESULT IN SLIGHTLY WARMER DAYTIME HIGH
TEMPERATURES EACH DAY, BUT OVERALL THIS SHOULD BE AT OR BELOW
AVERAGE. SOME STRONGER MOSTLY CHANNELIZED VORTICITY IS FORECAST TO
STREAM ACROSS THE AREA SATURDAY AND THIS SHOULD CONTINUE TO PROMOTE
SOME MORE CLOUDINESS ESPECIALLY WITH DAYTIME HEATING. THIS MAY ALSO
ASSIST IN SOME RAIN/SNOW SHOWERS MAINLY IN THE POCONO REGION GIVEN
THE TRAJECTORY OFF THE EASTERN GREAT LAKES. A WEAK SECONDARY COLD
FRONT OR SURFACE TROUGH MAY ALSO MOVE ACROSS OUR REGION LATER
SATURDAY. THE PRESENCE OF A TIGHTENED PRESSURE GRADIENT SHOULD ALSO
MAINTAIN A GUSTY WIND THROUGH MOST IF NOT ALL OF THE WEEKEND
(STRONGEST ON SATURDAY).
FOR MONDAY...THE FLOW ALOFT MAY TURN MORE ZONAL WITH WEAK HIGH
PRESSURE BUILDING ACROSS OUR AREA. THIS WILL RESULT IN MUCH LESS
WIND. TEMPERATURES SHOULD START TO MODERATE A LITTLE GIVEN SOME
INCREASE IN HEIGHTS ALOFT, WITH HIGH TEMPERATURES AT OR PERHAPS A
LITTLE ABOVE AVERAGE.
AVIATION /20Z MONDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REST OF THIS AFTERNOON...VFR. WEST TO NORTHWEST WINDS 10-15 KNOTS
WITH GUSTS TO AROUND 20 KNOTS. MODERATE CONFIDENCE.
TONIGHT...VFR. LIGHT W/NW WINDS. HIGH CONFIDENCE.
TUESDAY...VFR. LIGHT W/NW WINDS. HIGH CONFIDENCE.
OUTLOOK...
TUESDAY NIGHT...MAINLY VFR CEILINGS. A FEW SHOWERS POSSIBLE.
WEDNESDAY AND THURSDAY...MOSTLY VFR DURING THE DAY WEDNESDAY, THEN
SUB-VFR WEDNESDAY NIGHT INTO THURSDAY ALONG WITH SHOWERS OR A PERIOD
OF RAIN. A PERIOD OF WIND GUSTS UP TO 30 KNOTS AND AN ABRUPT WIND
SHIFT FROM SOUTHERLY TO NORTHWEST POSSIBLE LATER WEDNESDAY NIGHT.
GUSTY WEST-NORTHWEST WINDS CONTINUE THURSDAY.
FRIDAY AND SATURDAY...SOME TIMES OF SUB-VFR CONDITIONS WITH SOME
SHOWERS POSSIBLE, ESPECIALLY FRIDAY. NORTHWEST WIND GUSTS UP TO 30
KNOTS POSSIBLE.
MARINE
TONIGHT...SUB-SCA CONDITIONS EXPECTED, BUT SOME GUSTS TO 20 KTS AND
SEAS OF 4 FT ARE LIKELY THE SECOND HALF OF THE NIGHT.
TUESDAY...SUB-SCA CONDITIONS EXPECTED. LIGHT W WINDS WITH SEAS
MAINLY 2 TO 3 FT. WINDS COULD BACK TO THE SW DURING THE AFTERNOON.
OUTLOOK...
TUESDAY NIGHT...THE CONDITIONS ARE ANTICIPATED TO BE BELOW SMALL
CRAFT ADVISORY CRITERIA.
WEDNESDAY AND THURSDAY...SMALL CRAFT ADVISORY CONDITIONS STARTING
WEDNESDAY NIGHT. A PERIOD OF GALE FORCE WIND GUSTS POSSIBLE,
ESPECIALLY LATER WEDNESDAY NIGHT AND THURSDAY MORNING.
FRIDAY AND SATURDAY...SMALL CRAFT ADVISORY CONDITIONS PROBABLE. SOME
LOW-END GALE FORCE GUSTS POSSIBLE AT TIMES.
TIDES/COASTAL FLOODING
A COASTAL FLOOD ADVISORY IS IN EFFECT THROUGH TUESDAY MORNING'S
HIGH TIDE FOR OCEAN/ATLANTIC/CAPE MAY COUNTIES, WITH SPOTTY
MINOR FLOODING EXPECTED ELSEWHERE.
ONLY SPOTTY MINOR TIDAL FLOODING IS EXPECTED ON THE DELAWARE
COAST AND DELAWARE SIDE OF DELAWARE BAY FOLLOWING THIS MORNING'S
HIGH TIDE, THOUGH TIDE LEVELS COULD GET TO ADVISORY LEVEL WITH
TUESDAY MORNING'S HIGH TIDE. A COASTAL FLOOD ADVISORY MAY NEED
TO BE POSTED FOR THESE LOCATIONS.
COASTAL FLOODING IS NOT EXPECTED TO OCCUR ALONG THE CHESAPEAKE BAY
IN THE EASTERN SHORE OF MARYLAND OR THE TIDAL DELAWARE RIVER.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...COASTAL FLOOD ADVISORY UNTIL 3 PM EST TUESDAY FOR NJZ020-
022>027.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...GORSE
NEAR TERM...KRUZDLO
SHORT TERM...GORSE
LONG TERM...GORSE
AVIATION...GORSE/KRUZDLO
MARINE...GORSE/KRUZDLO
TIDES/COASTAL FLOODING...PHI
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