507
FXUS61 KPHI 161102
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
602 AM EST MON DEC 16 2024
SYNOPSIS
A WEAK UPPER AIR SYSTEM MOVES ACROSS OUR AREA EARLY TODAY,
FOLLOWED BY ANOTHER SYSTEM LATER TODAY 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.
NEAR TERM /THROUGH TONIGHT/
WE HAVE TAKEN THE WSW FLAG FOR WARREN COUNTY NJ DOWN SINCE
TEMPERATURES CONTINUE TO RISE ACROSS THE AREA. THE PRECIPITATION
WILL END THERE SHORTLY. OTHER AREAS WILL KEEP THE WSW FLAGS FOR
NOW WITH SOME COLD AIR LINGERING IN THE VALLEYS AND MORE QPF
EXPECTED FOR A FEW MORE HOURS.
THERE ARE TWO SYSTEMS IN THE TODAY/TONIGHT PERIODS. THE FIRST
IS BRINGING THE RAINS AND HIGHER ELEVATIONS SNOWS TO THE REGION
PRESENTLY. THE BACK EDGE OF THE PRECIPITATION WILL MOVE THRU
THIS MORNING AND THE WSW FLAGS WILL BE TAKEN DOWN AS THAT
OCCURS. MORE OF A NUISANCE SYSTEM AS THE OVERALL RAIN/SNOWS
AMOUNTS HAVE BEEN LIGHT.
THE BALANCE OF TODAY WILL FEATURE CLOUDS ACROSS THE AREA AND
EVEN THOUGH THERE WILL BE SOME RIDGING ALOFT, THERE ISN'T MUCH
DRY AIR IN THE LOWER LAYERS OF THE ATMOSPHERE AND MIXING WILL BE
WEAK TODAY. SO MOSTLY CLOUDY SKIES ARE EXPECTED. TEMPERATURES
WILL BECOME MILDER TODAY WHEN COMPARED TO SUNDAY AND HIGHS
SHOULD REACH THE LOW/MID 50S FOR THE S/SE AREAS WHILE LOW/MID
40S ARE EXPECTED N/W.
FOR TONIGHT, ANOTHER FAST MOVING SYSTEM IS PROGGED TO MOVE
ACROSS PA AND NJ EARLY TONIGHT AND THEN GO OFFSHORE OVERNIGHT.
MORE CLOUDS AND RAINS WILL ACCOMPANY THE SYSTEM. AGAIN, RAIN
TOTALS WILL NOT BE THAT GREAT, PERHAPS 1/4 TO 1/2 INCH AT MOST.
IT'LL REMAIN MILD TONIGHT WITH LOWS IN THE MID/UPPER 40S MOST
SPOTS AND SOME LOW 40S N/W.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
LOW PRESSURE WILL BE MOVING EAST AWAY FROM THE REGION TUESDAY
MORNING, WITH RAIN SUBSIDING QUICKLY BUT CLOUDS LINGERING AS A
SLOW MOVING COLD FRONT SLOWLY PUSHES SOUTHEAST INTO THE AREA. AS
THE FRONT PASSES, WE SHOULD WARM UP AND SUNNY UP BRIEFLY, SO
TUESDAY MIDDAY AND AFTERNOON ACTUALLY LOOK LIKE THE MOST
PLEASANT PORTION OF THE NEXT 7 DAYS, AT LEAST IF YOU PREFER ROOM
TEMPERATURES AND DRY WEATHER. HIGHS SHOULD APPROACH 60 FOR MUCH
OF THE AREA, ESPECIALLY FROM PHL SOUTHWARD... COOLER NORTH AND
AT THE SHORE.
A MORE SEASONABLE AND CERTAINLY DRY NIGHT IS ON TAP WITH WEAK
HIGH PRESSURE IN CONTROL TUESDAY NIGHT. 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.
THAT NEXT 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.
LONG TERM /THURSDAY THROUGH SUNDAY/
COLDER AIR FINALLY ARRIVES THURSDAY BEHIND WEDNESDAY NIGHT'S LOW
PRESSURE, AND WOULD YOU BELIEVE IT, BUT HIGH SHOULD BE BACK TO
NEAR NORMAL, WITH MOST AREAS SOMEWHERE IN THE 40S. IT SHOULD
ALSO BE DRY AS HIGH PRESSURE BRIEFLY TAKES HOLD, SO IF YOUR
PREFERENCE IS FOR SEASONABLE TEMPS AND DRY WEATHER, THURSDAY IS
YOUR DAY. A LITTLE BIT COLDER THURSDAY NIGHT, WITH LOWS MOSTLY
BELOW FREEZING, BUT STILL DRY.
HAVE HELD ONTO SOME CHANCE POPS FOR THE POTENTIAL CLIPPER SYSTEM
SWINGING BY ON FRIDAY INTO FRIDAY NIGHT, THOUGH LATEST
OPERATIONAL MODELS HAVE TRENDED NOTABLY DRIER AS THE LOW
PRESSURE MOSTLY FIZZLES AND STAYS A BIT FURTHER NORTH. THUS, A
CHANCE OF RAIN AND SNOW, BUT ODDS RIGHT NOW APPEARS 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.
AVIATION /12Z MONDAY THROUGH FRIDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS...
TODAY... LIMITED CONFID FCST WITH THE 12Z TAFS RAINS END SHORTLY
FROM WEST TO EAST, BUT NO STRONG MIXING EXPECTED TODAY. THE 'ALL
DAY' LIFR CIGS SEEM TOO PESSIMISTIC. DECIDED TO BRING LIMITED
IMPROVEMENT LATE MORNING AND INTO THE AFTERNOON WITH HIGH-END
IFR/LOW-END MVFR POSSIBLE. E/SE WINDS WILL BECOME S OR SW THIS
EVENING. LOW CONFID.
TONIGHT... ANOTHER QUICK MOVING SYSTEM WITH RAINS AND LOW
CIGS/VSBYS EXPECTED. AGAIN, MOSTLY IFR BUT LIFR POSSIBLE.
SOUTHWEST WINDS AROUND 10 KNOTS. LOW CONFID OVERALL.
OUTLOOK...
IFR CONDITIONS WILL BREAK FOR VFR NEAR MIDDAY TUESDAY AND REMAIN
VFR THROUGH MIDDAY WEDNESDAY. CONDITIONS LIKELY SLIDE BACK TO
IFR LATE WEDNESDAY AND WEDNESDAY EVENING AS ANOTHER LOW PRESSURE
BRINGS ANOTHER ROUND OF RAIN AND LOW CLOUDS/REDUCED VSBY.
IMPROVING BACK TO VFR LATE WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT. REDUCTIONS TO MVFR POSSIBLE WITH A WEAKER SYSTEM FRIDAY.
MARINE
NO CHANGES NEEDED TO THE SCA FLAGS ACROSS THE WATERS WITH
INCREASING WINDS AND SEAS FROM SOUTH TO NORTH TODAY AND TONIGHT.
RAINS ENDING THIS MORNING THEN MORE RAINS TONIGHT. AREAS OF FOG
POSSIBLE.
OUTLOOK...
SCA CONDITIONS GRADUALLY SUBSIDE TUESDAY AND IT SHOULD REMAIN
BELOW SCA LEVELS TUESDAY NIGHT INTO WEDNESDAY IN THE WAKE OF
ANOTHER LOW PRESSURE. SCA RETURNS WEDNESDAY NIGHT THROUGH
THURSDAY BEHIND YET ANOTHER LOW PRESSURE SYSTEM. THAT SCA SHOULD
SUBSIDE THURSDAY NIGHT AND IT LIKELY REMAINS BELOW SCA LEVELS
FRIDAY.
PHI WATCHES/WARNINGS/ADVISORIES
PA...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ054-
055.
NJ...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR NJZ001-
008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST TUESDAY FOR
ANZ450.
SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR ANZ451.
SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR ANZ452>455.
SYNOPSIS...OHARA/RCM
NEAR TERM...OHARA
SHORT TERM...RCM
LONG TERM...RCM
AVIATION...OHARA/RCM
MARINE...OHARA/RCM
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