994  
FXUS61 KPHI 142023  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
323 PM EST TUE JAN 14 2025  
   
SYNOPSIS
 
 
COLD AND DRY ARCTIC HIGH PRESSURE WILL REMAIN IN PLACE TO OUR  
WEST THROUGH THE MIDDLE OF THE WEEK, KEEPING BELOW NORMAL  
TEMPERATURES AND DRY CONDITIONS IN PLACE. A WEAK WAVE OF LOW  
PRESSURE WILL PASS THROUGH ON THURSDAY. A WARM FRONT WILL LIFT  
NORTH ON SATURDAY, BRINGING A SHOT OF WIDESPREAD PRECIPITATION.  
A STRONG ARCTIC COLD FRONT WILL PASS THROUGH SUNDAY, WITH A WAVE  
OF LOW PRESSURE RIDING BEHIND IT WHICH MAY PRODUCE A LITTLE  
SNOW. MUCH COLDER CONDITIONS ARE EXPECTED NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH WEDNESDAY/
 
 
A SUNNY BUT BRISK JANUARY DAY IS ONGOING AS TEMPERATURES THIS  
AFTERNOON ARE CURRENTLY IN THE UPPER 20S TO LOW 30S. NORTHWEST  
WINDS GUSTING BETWEEN 25-35 MPH HAVE RESULTED IN WIND CHILL  
VALUES IN THE TEENS AND 20S THIS AFTERNOON.  
 
COLD CANADIAN HIGH PRESSURE CURRENTLY OVER THE NORTHERN PLAINS  
WILL MOVE SOUTHEAST OVER THE MIDWEST TONIGHT BEFORE SETTLING  
NEAR TENNESSEE ON WEDNESDAY. ALSO, A SHORTWAVE ALOFT WILL PASS  
THROUGH THE MID-ATLANTIC REGION THIS EVENING. AS IT DOES SO,  
SHOULD SEE AN INCREASE IN MID/LOW LEVEL CLOUDS AROUND SUNSET.  
ALTHOUGH ATMOSPHERIC PROFILES ARE QUITE DRY, ISOLATED FLURRIES  
AND SNOW SHOWERS WILL BE POSSIBLE. THUS, HAVE INCLUDED THE  
MENTION OF FLURRIES TO THE ENTIRE FORECAST AREA THROUGH THE  
EARLY EVENING. NO ACCUMULATIONS ARE EXPECTED. OTHERWISE, SKIES  
WILL BEGIN TO CLEAR AROUND MIDNIGHT FROM NORTH TO SOUTH. IT  
SHOULD REMAIN QUITE BREEZY OVERNIGHT WITH WIND GUSTS UP TO 30  
MPH AS FORECAST SOUNDINGS ONLY INDICATE A WEAK INVERSION  
DEVELOPING. LOWS WILL BE IN THE TEENS TO LOW 20S. WHEN FACTORING  
IN THE WIND, WIND CHILL VALUES ARE EXPECTED TO BE IN THE SINGLE  
DIGITS (SUB-ZERO IN THE POCONOS). WILL FALL SHORT OF COLD  
WEATHER HAZARDS, HOWEVER.  
 
WEDNESDAY WILL ESSENTIALLY BE A CARBON COPY OF TODAY AS NO REAL  
CHANGE TO THE WEATHER PATTERN IS TO OCCUR. TEMPERATURES MAY IN  
FACT BE A DEGREE OR TWO HIGHER THAN TODAY, WITH HIGHS TOPPING  
OUT IN THE UPPER 20S TO MID 30S UNDER MOSTLY CLEAR SKIES. WINDS  
WILL REMAIN ON THE BREEZY SIDE AS THE MODEST PRESSURE GRADIENT  
PERSISTS WITH WINDS GUSTING UP TO 30 MPH FOR WEDNESDAY  
AFTERNOON. AGAIN, WIND CHILL VALUES SHOULD MAINLY BE IN THE  
TEENS AND 20S.  
 

 
   
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
 
 
MAIN FEATURE OF THE SHORT TERM, OTHER THAN COLD, IS A WEAK LOW  
PRESSURE PASSING SOUTHEASTWARD ACROSS THE REGION THURSDAY  
EVENING. BEFORE THEN, MAINLY DRY AND COLD WEDNESDAY NIGHT INTO  
EARLY THURSDAY AS SURFACE HIGH PRESSURE BRIEFLY BUILDS IN BEFORE  
PASSING SOUTHEASTWARD INTO THE ATLANTIC. LOWS MOSTLY IN THE  
TEENS.  
 
WE'LL START WITH SOME SUN THURSDAY MORNING, BUT CLOUDS LIKELY  
FILL IN FAIRLY WELL BY EARLY AFTERNOON. MOST GUIDANCE HAS AT  
LEAST A BIT OF LIGHT PRECIP OVERSPREADING THE AREA WITH WARM  
ADVECTION AND DIVERGENCE ALOFT AS THE SURFACE LOW AND ITS UPPER  
LVEL TROUGH MOVES INTO THE REGION. THUS, HAVE CHANCE POPS MAINLY  
NORTHWEST OF I-95 LATE THURSDAY AFTERNOON INTO THURSDAY EVENING,  
SLIGHT CHANCE ELSEWHERE, BUT LITTLE IF ANY MEASURABLE SNOW  
EXPECTED. WHERE IT DOES OCCUR, TOTALS SHOULD BE LESS THAN A  
HALF INCH. HIGHS MID 30S DELMARVA AND SOUTH JERSEY, NEAR  
FREEZING I-95, NEAR 30 I-78 CORRIDOR, 20S POCONOS AND NW NJ,  
WITH LOWS NEAR 20 FOR MOST, TEENS POCONOS AND NW NJ.  
 
THE PASSAGE OF THE SYSTEM WILL BEGIN TO BRING WARMER AIR INTO  
THE REGION AS A PACIFIC HIGH PRESSURE BUILDS EASTWARD INTO THE  
REGION, ACCOMPANIED BY PARTLY TO MOSTLY SUNNY SKIES. THIS WILL  
PROBABLY MAKE FRIDAY THE NICEST DAY OF THE CURRENT 7-DAY  
FORECAST. HIGHS NEAR 40 FOR MOST.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
 
 
HIGH PRESSURE HEADS OFF THE COAST FRIDAY NIGHT INTO SATURDAY AS  
THE NEXT STORM MOVES INTO THE REGION. SOUTHERLY FLOW AND  
INCREASING CLOUDS WILL KEEP LOWS A BIT MILDER, WITH MOST PLACES  
STAYING IN THE MID 20S TO NEAR 30.  
 
CLOUDS WILL PREDOMINATE SATURDAY AS THE AFOREMENTIONED SYSTEM  
MOVES INTO THE REGION. THE MORNING STILL LOOKS DRY, BUT RAIN  
CHANCES INCREASE DURING THE AFTERNOON AND CONTINUE INTO SATURDAY  
NIGHT. THAT SAID, TOTAL AMOUNTS LOOK QUITE MEAGER, SO NOT A  
WASHOUT OR HEAVY RAIN RISK AT ALL. TEMPS WILL BE A LITTLE  
MILDER, WITH HIGHS MOSTL IN THE LOW-MID 40S, WITH LOWS DROPPING  
TO NEAR FREEZING OR JUST BELOW SATURDAY NIGHT AFTER RAIN PULLS  
OUT.  
 
A BRIEF BREAK TAKES HOLD SUNDAY AS AN ARCTIC FRONT MOVES  
THROUGH. THEN A POTENT UPPER LEVEL SHORTWAVE LOOKS TO POSSIBLY  
DEVELOP A NEW LOW JUST OFF THE COAST LATE SUNDAY INTO EARLY  
MONDAY, WITH SIGNIFICANT UNCERTAINTY IN TIMING. WITH THE SYSTEM  
REMAINING OFF SHORE AND DEVELOPING PRETTY LATE, PRECIP AMOUNTS  
LOOK LIGHT, BUT BY THIS POINT, IT SHOULD BE COLD ENOUGH FOR MOST  
IF NOT ALL PRECIP TO BE SNOW, SO A WIDESPREAD IF LIGHT  
ACCUMULATING SNOW REMAINS POSSIBLE SUNDAY NIGHT. THIS LIKELY  
PULLS OUT PRETTY QUICKLY MONDAY, WITH THE WELL-ADVERTISED VERY  
COLD AIR MASS BUILDING SOUTHEASTWARD INTO THE REGION  
THEREAFTER.  
 

 
   
AVIATION /19Z TUESDAY THROUGH SUNDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
REST OF TODAY...VFR WITH CLEAR SKIES. BY 22Z, A BKN CLOUD DECK  
SHOULD OVERSPREAD ALL TERMINALS BETWEEN 6000-8000 FEET. WEST-  
NORTHWEST WINDS AROUND 10-20 KT WITH GUSTS UP TO 25 KT. HIGH  
CONFIDENCE.  
 
TONIGHT...VFR. BKN CEILINGS EARLY, BECOMING MOSTLY CLEAR AFTER  
03- 04Z. WEST-NORTHWEST WINDS AROUND 10-15 KT. GUSTS MAY  
OCCASIONAL GUST UP TO 20 KT. HIGH CONFIDENCE.  
 
WEDNESDAY...VFR WITH FEW/SCT AFTERNOON CLOUDS. WEST-NORTHWEST  
WINDS AROUND 10-15 KT WITH GUSTS UP TO 25 KT. HIGH CONFIDENCE.  
 
OUTLOOK...  
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...MOSTLY VFR. A FEW SNOW  
SHOWERS THURSDAY AFTERNOON/EVENING MAY BRIEFLY REDUCE CONDITIONS  
BELOW VFR, MOST LIKELY AFFECTING KRDG AND KABE.  
 
SATURDAY AND SATURDAY NIGHT...SUB-VFR POSSIBLE WITH A BIT OF  
RAIN OR SOME SHOWERS, LOWERING CIGS AND VSBY.  
 
SUNDAY...MOSTLY VFR, DEPENDING ON TIMING OF THE EXIT OF THE RAIN  
SATURDAY NIGHT AND THE ARRIVAL OF POTENTIAL LIGHT SNOW  
SUNDAY NIGHT.  
 

 
   
MARINE
 
 
A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL ATLANTIC COASTAL  
WATERS AND THE DELAWARE BAY THROUGH 6 PM TODAY. A GALE WARNING  
IS IN EFFECT FOR ALL ATLANTIC COASTAL WATERS AND THE DELAWARE  
BAY INTO WEDNESDAY MORNING. A FREEZING SPRAY ADVISORY IS IN  
EFFECT FOR ALL ATLANTIC COASTAL WATERS AND THE DELAWARE BAY  
THROUGH EARLY WEDNESDAY AFTERNOON.  
 
WEST-NORTHWEST WINDS AROUND 15-25 KT WITH GUSTS UP TO 30 KT ARE  
EXPECTED FOR THE REMAINDER OF TODAY WITH SEAS AROUND 3-5 FEET.  
FOR TONIGHT, NORTHWEST WINDS WILL INCREASE TO 20-30 KT WITH  
GUSTS UP TO 35-40 KT AND SEAS OF 4-6 FEET. ON WEDNESDAY,  
NORTHWEST WINDS WILL DIMINISH A BIT THROUGH THE AFTERNOON, BUT  
GUSTS UP TO 30 KT REMAIN POSSIBLE.  
 
DUE TO THE COMBINATION OF COLD AIR/WATER TEMPERATURES, GUSTY  
WINDS, AND ENHANCED SEAS, MODERATE FREEZING SPRAY ACCRETION IS  
LIKELY BEGINNING TONIGHT THROUGH EARLY WEDNESDAY AFTERNOON.  
 
OUTLOOK...  
WEDNESDAY NIGHT...CONDITIONS SUBSIDING SLOWLY BUT MOSTLY STILL  
AT SCA LEVELS WITH GUSTS UP TO 30 KTS AND SEAS UP TO 6 FEET,  
MAINLY EARLY. FREEZING SPRAY POSSIBLE.  
 
THURSDAY...GENERALLY BELOW SCA LEVELS WITH WIND GUSTS MOSTLY  
BELOW 25 KTS AND SEAS MOSTLY BELOW 4 FEET.  
 
THURSDAY NIGHT...SCA CONDITIONS RETURN WITH GUSTS UP TO 30 KTS,  
BUT SEAS STILL MOSTLY BELOW 4 FEET. A FEW SNOW SHOWERS  
POSSIBLE.  
 
FRIDAY THROUGH FRIDAY NIGHT...SUB-SCA OVERALL WITH GUSTS MOSTLY  
BELOW 25 KTS AND SEAS BELOW 4 FEET.  
 
SATURDAY...SCA CONDITIONS REDEVELOP WITH GUSTS UP TO 25 KTS AND  
SEAS BUILDING TO 5 FEET. RAIN ALSO POSSIBLE.  
 
SATURDAY NIGHT...CONDITIONS DROPPING BACK BELOW SCA WITH GUSTS  
MOSTLY BELOW 25 KTS AND SEAS SUBSIDING TO 4 FEET OR LESS. RAIN  
ALSO POSSIBLE.  
 
SUNDAY...SCA RAMPS BACK UP WITH GUSTS TO 25 KTS AND SEAS  
BUILDING BACK TO 5 FEET.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-  
431-450>455.  
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR  
ANZ430-431-450>455.  
FREEZING SPRAY ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST  
WEDNESDAY FOR ANZ430-431-450>455.  
 

 
 

 
 
SYNOPSIS...DESILVA/RCM  
NEAR TERM...DESILVA  
SHORT TERM...RCM  
LONG TERM...RCM  
AVIATION...DESILVA/RCM  
MARINE...DESILVA/RCM  
 
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