895
FXUS61 KPHI 170238
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
938 PM EST MON DEC 16 2024
SYNOPSIS
THE NEXT LOW PRESSURE SYSTEM MOVES IN LATER THIS EVENING AND
CONTINUES INTO EARLY TUESDAY. HIGH PRESSURE LOOKS TO BUILD IN
BRIEFLY LATER TUESDAY BEFORE ANOTHER LOW PRESSURE SYSTEM AFFECTS
OUR REGION LATER WEDNESDAY. HIGH PRESSURE MOVES IN ON THURSDAY,
WITH A CLIPPER SYSTEM POTENTIALLY MOVING INTO THE AREA TO CLOSE
OUT THE WEEK. MUCH COLDER WEATHER ARRIVES BY THE END OF THE
WEEKEND, POTENTIALLY CONTINUING INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TUESDAY/
A DREARY AND WET START TO THE WEEK IS ONGOING. A WARM FRONT IS
TRYING TO PUSH NORTHWARD, BUT STRUGGLING WITH SOME PESKY COLD
AIR VIA COLD AIR DAMMING REMAINING IN PLACE NEAR AND NORTH OF
I-78. SOUTHWESTERLY FLOW WILL STRENGTHEN THOUGH, PUSHING THE
WARM FRONT THROUGH THE NORTHERN AREAS OVERNIGHT. THROUGH THIS
EVENING AHEAD OF THE APPROACHING RAIN, AREAS OF FOG AND SOME
DRIZZLE WILL PERSIST. SOME DENSE FOG CONTINUES ACROSS THE
SOUTHERN POCONOS, OTHER NEARBY HIGHER TERRAIN, AND ALONG THE
IMMEDIATE COAST, BUT IT HAS BEEN TRANSIENT AND PATCHY ENOUGH TO
PRECLUDE AN ADVISORY.
FOR TONIGHT, A WEAK AREA OF LOW PRESSURE MOVES BY TO THE NORTH.
RAIN WILL BEGIN TO OVERSPREAD THE AREA THIS EVENING AS
ISENTROPIC FORCING INCREASES. A SOUTHWESTERLY LOW-LEVEL JET WILL
ALSO ENHANCE RAINFALL, WITH PERIODS OF RAIN EXPECTED THROUGH
AROUND 2-4 AM. THE INCOMING SYSTEM WILL BE ON THE FASTER SIDE,
WITH RAINFALL AMOUNTS ONLY GETTING INTO THE 0.1"-0.3" INCH
RANGE. LOCALLY HIGHER AMOUNTS ARE POSSIBLE, BUT NOTHING MORE
THAN A HALF INCH. WITH THE WARM FRONT MOVING THROUGH THIS
EVENING, AND WARM AIR ADVECTION STRENGTHENING, TEMPERATURES WILL
ACTUALLY RISE OVERNIGHT, GETTING INTO THE UPPER 40S/LOW 50S.
RAIN MOVES OUT BY DAYBREAK, THOUGH THE COLD FRONT AND ENSUING
COLD- AIR ADVECTION WILL LAG BEHIND A BIT. MOSTLY CLOUDY SKIES
AND SOME LINGERING FOG POSSIBLE THROUGH LATE MORNING, THEN
CLEARING OUT INTO THE AFTERNOON. TEMPERATURES WILL CLIMB INTO
THE MID TO UPPER 50S/LOW 60S WITH SKIES CLEARING OUT AS THE DAY
GOES ON.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/
A MORE SEASONABLE AND CERTAINLY DRY NIGHT IS ON TAP FOR TUESDAY
NIGHT WITH WEAK HIGH PRESSURE IN CONTROL. LOWS WILL BE ABOUT 10
DEGREES BELOW THOSE EXPECTED TONIGHT, MOSTLY IN THE 30S, WHICH
IS STILL A LITTLE ON THE PLUS SIDE OF NORMAL, BUT NOT NEARLY AS
MUCH AS IT WILL BE TONIGHT.
NEXT LOW PRESSURE APPROACHES FROM THE SOUTHWEST ON WEDNESDAY,
SO WHILE IT SHOULD START OUT DRY WITH A BIT OF SUN, CLOUDS
INCREASE AS THE DAY WEARS ON WITH RAIN LIKELY ARRIVING IN THE
AFTERNOON. GUIDANCE HAS WAVERED ON THIS A BIT, WITH SOME
GUIDANCE LIKE THE LATEST GFS HOLDING OFF ON THE RAIN FOR THE
I-95 CORRIDOR ON SOUTH AND EAST UNTIL EVENING, BUT IT STILL
LOOKS LIKELY TO RAIN AT SOME POINT LATER WEDNESDAY INTO
WEDNESDAY NIGHT. HIGHS WILL BE ABOUT 10 DEGREES BELOW TUESDAY'S
HIGHS, UPPER 40S TO LOW 50S FOR THE MOST PART, WHICH IS STILL
ABOVE NORMAL, BUT NEARLY AS FAR ABOVE AS TUESDAY.
THE LOW PRESSURE PULLS EAST OF THE REGION OVERNIGHT WEDNESDAY,
WITH PERHAPS A LITTLE SNOW IN THE POCONOS ON THE TAIL END, BUT
OVERALL, A MOSTLY NON-WINTRY SYSTEM. IN FACT, THERE ISN'T AN
IMMEDIATE COLD PUSH BEHIND IT, SO LOWS MOSTLY STAY ABOVE
FREEZING EXCEPT IN THE POCONOS. BY DAYBREAK THURSDAY, THE AREA
SHOULD BE DRY ONCE AGAIN AS HIGH PRESSURE BEGINS TO BUILD IN
WITH COLDER AIR FOLLOWING BEHIND THE DEPARTING LOW. HIGHS MAINLY
IN THE 40S ARE EXPECTED.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
COLDER AIR CONTINUES TO MOVE IN THROUGH THE LONG TERM AS HIGH
PRESSURE REMAINS LARGELY IN CONTROL.
THE EXCEPTION BEING A POTENTIAL CLIPPER SYSTEM SWINGING BY ON
FRIDAY INTO FRIDAY NIGHT. HAVE CONTINUED TO HOLD ONTO SLIGHT
CHANCE TO CHANCE POPS (MAINLY 20-30%) BUT THE LATEST OPERATIONAL
MODELS HAVE CONTINUED THE NOTABLY DRIER TREND AS THE LOW
PRESSURE MOSTLY FIZZLES AND STAYS A BIT FURTHER NORTH. THUS, A
CHANCE OF RAIN AND SNOW, BUT ODDS RIGHT NOW APPEAR TO CONTINUE
TO BE DIMINISHING THAT THERE WILL BE ANY IMPACT FROM THIS
SYSTEM. HIGHS WILL DROP A FEW DEGREES, BUT STILL NOT FAR FROM
NORMAL.
THAT PART CHANGES AS WE HEAD INTO THE WEEKEND, AND ANOTHER
STRONG CANADIAN HIGH PRESSURE BUILDS SOUTHWARD ACROSS OUR
REGION. THIS ONE MAY BE ACCOMPANIED BY THE COLDEST AIR SINCE
LAST JANUARY, RIVALING LAST WINTER'S COLDEST DAYS, WITH HIGHS BY
SUNDAY POTENTIALLY STAYING IN THE 20S AND LOWS IN THE SINGLE
DIGITS AND TEENS. THE LACK OF SNOW COVER LIKELY KEEPS THINGS A
LITTLE MORE MODERATE, BUT EITHER WAY, IT COULD BE QUITE A SHOCK
TO THE SYSTEM. SO, IF YOU LIKE REALLY COLD AND DRY WEATHER,
SUNDAY IS STARTING TO LOOK LIKE YOUR FAVORITE DAY OF THE
FORECAST. TEMPERATURES MAY BEGIN TO MODERATE SLIGHTLY INTO
MONDAY, AS THE CENTER OF THE HIGH SHIFTS EASTWARD, BUT DRY
CONDITIONS LOOK TO CONTINUE.
AVIATION /03Z TUESDAY THROUGH SATURDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS...
TONIGHT... ANOTHER QUICK MOVING SYSTEM WITH LOW CIGS/VSBYS AND
PERIODS OF RAIN EXPECTED. PRIMARILY LIFR/IFR WITH AN
IMPROVEMENT TO IFR AFTER THE RAIN ENDS BY 09Z FOR THE REMAINING
SITES WITH LIFR CIGS. SOUTH TO SOUTHWEST WINDS INCREASING TO
AROUND 5-10 KNOTS. SOME GUSTS NEAR 18-20 KTS POSSIBLE, BUT THESE
WILL LIKELY NOT PREVAIL, AND HAVE NOT BEEN INCLUDED IN THE
TAFS. LLWS ANTICIPATED AT MOST SITES DURING THE PERIOD OF
RAINFALL OVERNIGHT. HIGH CONFIDENCE IN PREVAILING LIFR/IFR, LOW
CONFIDENCE ON TIMING OF ANY IMPROVEMENT.
TUESDAY...PRIMARILY IFR TO START, BUT CONDITIONS IMPROVING TO
VFR BY 15-18Z. WHILE CEILINGS LIKELY REMAIN IFR, VISIBILITY
SHOULD BEGIN TO IMPROVE BY 12Z OR SO. SOUTHWEST WINDS AROUND 10
KTS EARLY SHIFTING WESTERLY AROUND 15-18Z WITH SOME 18-20 KTS
GUSTS AT TIMES. MODERATE CONFIDENCE IN TIMING OF IMPROVEMENT.
OUTLOOK...
TUESDAY NIGHT...VFR WITH NO SIGNIFICANT WEATHER.
WEDNESDAY...MAINLY VFR CONDITIONS TO START. INCREASING
RESTRICTIONS, LIKELY TO IFR, BY LATE WEDNESDAY INTO WEDNESDAY
NIGHT AS WIDESPREAD RAIN MOVES INTO THE REGION, CONTINUING
THROUGH MUCH OF WEDNESDAY NIGHT. CONDITIONS BEGIN TO IMPROVE
BACK TOWARDS VFR LATE WEDNESDAY NIGHT AS RAIN CLEARS OUT OF THE
REGION.
THURSDAY...VFR CONDITIONS EXPECTED.
FRIDAY...SUB-VFR CONDITIONS POSSIBLE WITH A CHANCE FOR RAIN
AND/OR SNOW.
SATURDAY...VFR CONDITIONS EXPECTED.
MARINE
SOME AREAS OF FOG WITH VISIBILITY NEAR 1 NAUTICAL MILE HAVE BEEN
OBSERVED IN THE NEARSHORE WATERS THIS EVENING. AREAS OF FOG AND
PERIODS OF RAIN WILL PERSIST OVERNIGHT.
A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OCEAN ZONES UNTIL 1
PM TOMORROW. THE SCA CONTINUES THROUGH THE REMAINDER OF TUESDAY
FOR COASTAL ZONES NORTH OF GREAT EGG INLET. SEAS OF 4 TO 6 FEET
ARE EXPECTED THOUGH WIND GUSTS OUT OF THE SOUTHWEST COULD GET
NEAR 25 KT AT TIMES TONIGHT.
ON DELAWARE BAY, NO MARINE HEADLINES EXPECTED AS WINDS WILL BE
MUCH LIGHTER, GENERALLY AROUND 10-20 KT OUT OF THE
SOUTH/SOUTHWEST THROUGH TOMORROW MORNING, BECOMING WESTERLY FOR
THE AFTERNOON.
OUTLOOK...
TUESDAY NIGHT THROUGH WEDNESDAY...MAINLY SUB-SMALL CRAFT
ADVISORY CONDITIONS BUT WIND GUSTS AROUND 20 KNOTS POSSIBLE
WEDNESDAY.
WEDNESDAY NIGHT THROUGH THURSDAY...SCA CONDITIONS POSSIBLE AS
WINDS INCREASE TO AROUND 25 KNOTS WITH AROUND 5 FOOT SEAS.
THURSDAY NIGHT THROUGH FRIDAY...SUB-SCA CONDITIONS EXPECTED.
SATURDAY...SCA CONDITIONS POSSIBLE.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR ANZ450-451.
SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR ANZ452>455.
SYNOPSIS...AKL/RCM
NEAR TERM...HOEFLICH/STAARMANN
SHORT TERM...AKL/RCM
LONG TERM...AKL/RCM
AVIATION...AKL/HOEFLICH/STAARMANN
MARINE...AKL/HOEFLICH/STAARMANN
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