654  
FXUS61 KPHI 161740  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
1240 PM 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/
 
 
THE MAJORITY OF SHOWERS HAVE MOVED OUT, THOUGH DRIZZLE AND  
PATCHY FOG REMAIN. THIS WILL GENERALLY BE THE THEME FOR THE REST  
OF THE DAY. 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 /18Z MONDAY THROUGH SATURDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS...  
 
REST OF TODAY...PRIMARILY LIFR CIGS, THOUGH BRIEF IMPROVEMENTS  
TO IFR POSSIBLE, MAINLY AT THE I-95 AND SOUTH JERSEY TERMINALS.  
MVFR/IFR VISIBILITY EXPECTED. WINDS BECOMING SOUTHERLY AROUND  
5-10 KT. HIGH CONFIDENCE IN PREVAILING LIFR/IFR.  
 
TONIGHT... ANOTHER QUICK MOVING SYSTEM WITH RAINS AND LOW  
CIGS/VSBYS EXPECTED. PRIMARILY LIFR WITH AN IMPROVEMENT TO IFR  
AT SOME POINT, PERHAPS AFTER MIDNIGHT. SOUTHWEST WINDS AROUND  
10 KNOTS. LOW-LEVEL WIND SHEAR ANTICIPATED AT KRDG/KMIV/KACY,  
WITH SOME BRIEF PERIODS OF LLWS POSSIBLE AT KTTN AND KABE. HIGH  
CONFIDENCE IN PREVAILING LIFR/IFR, LOW CONFIDENCE ON TIMING OF  
IMPROVEMENT.  
 
TUESDAY...PRIMARILY IFR TO START, BUT CONDITIONS IMPROVING TO  
VFR BY THE LATE MORNING/EARLY AFTERNOON. WINDS OUT OF THE  
SOUTHWEST AROUND 10 KT. MODERATE CONFIDENCE IN TIMING OF  
IMPROVEMENT.  
 
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
 
 
A SMALL CRAFT ADVISORY IS IN PLACE FOR ALL COASTAL WATERS AS  
SEAS ARE AROUND 5 TO 6 FEET AT ALL BUOYS. WINDS GET CLOSE TO 25  
KT LATE 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...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...OHARA/RCM  
NEAR TERM...HOEFLICH/OHARA  
SHORT TERM...RCM  
LONG TERM...RCM  
AVIATION...HOEFLICH/OHARA/RCM  
MARINE...HOEFLICH/OHARA/RCM  
 
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