369  
FXUS61 KPHI 240816  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
316 AM EST SAT FEB 24 2024  
   
SYNOPSIS
 
 
A COLD FRONT WILL MOVE ACROSS THE REGION THIS MORNING. HIGH  
PRESSURE BUILDS IN FROM THE WEST AND MOVES OFFSHORE BY MONDAY. A  
WEAK COLD FRONT PASSES THROUGH THE REGION ON MONDAY, FOLLOWED  
BY A WARM FRONT ON TUESDAY. SEVERAL WAVES OF LOW PRESSURE WILL  
THEN PASS THROUGH THE REGION UNTIL A COLD FRONT MOVES THROUGH  
THE REGION ON THURSDAY. HIGH PRESSURE RETURNS FOR THE END OF THE  
WORK WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
BOTH GLOBAL AND CAM GUIDANCE ARE NOW LOCKED IN WITH THE  
APPROACHING SHOWERS ACROSS SOUTH-CENTRAL PENNSYLVANIA. THE  
NORTHERN EXTENT OF THE PRECIPITATION SHOULD BE ABOUT THE PA  
TURNPIKE AND 195 IN NJ. THE SHOWERS ARE MOVING INTO SE PA NOW,  
SHOULD GET INTO THE PHILLY VICINITY AROUND DAYBREAK AND CROSS  
SOUTHERN NJ AND THE DELMARVA DURING THE MORNING HOURS. MOST, IF  
NOT ALL OF THE LIGHT PRECIPITATION, SHOULD BE MOVING OFF THE  
COAST MIDDAY. SOUNDINGS SUPPORT SOME WET SNOW, BUT WITH  
TEMPERATURES HOVERING IN THE LOWER TO MIDDLE 30S AND INTENSITIES  
EXPECTED TO BE LIGHT, ACCUMULATION ON AREA ROADS ARE NOT  
EXPECTED.  
 
ONLY PARTIAL CLEARING IS EXPECTED THE SECOND HALF OF THE DAY AS  
DRIER AIR BEGINS TO ADVECT INTO THE FORECAST AREA. WINDS WILL  
BE NOTICEABLE TODAY BEHIND THE COLD FRONT. IT WILL BE A BIT  
BREEZY WITH WINDS AROUND 10 TO 15 MPH AND GUSTS UP TO 25 MPH.  
HIGH TEMPERATURES ARE FORECAST TO BE MAINLY IN THE UPPER 30S TO  
MIDDLE 40S, EXCEPT UPPER 20S AND LOWER 30S ACROSS THE HIGHER  
ELEVATIONS NORTH AND WEST.  
 
HIGH PRESSURE AT THE SURFACE AND MID-LEVELS WILL BUILD INTO THE  
REGION TONIGHT. BOTH THE MID-LEVEL RIDGE AXIS AND SURFACE HIGH  
AXIS ARE FORECAST TO BE ON TOP OF US BY DAYBREAK. THIS WILL  
RESULT IN CLEAR SKIES AND A RELAXING PRESSURE GRADIENT,  
ESPECIALLY THE SECOND HALF OF THE OVERNIGHT. SO WITH FAVORABLE  
RADIATIONAL COOLING CONDITIONS, LOWS WILL DROP INTO THE TEENS  
AND LOWER 20S. THE SOUTHERN POCONOS COULD SEE LOWS DIP TO AROUND  
10 DEGREES.  
 

 
   
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
 
 
ELONGATED SURFACE HIGH PRESSURE WILL EXTEND FROM THE NORTHEAST  
THROUGH THE MID-ATLANTIC AND INTO THE SOUTHEAST AND GULF COAST  
STATES. UPPER TROUGH WILL MOVE OFFSHORE BY SUNDAY MORNING, AND  
ZONAL FLOW ALOFT WILL SET UP. TEMPERATURES WARM BACK UP TO  
NORMAL LEVELS ON SUNDAY WITH HIGHS GENERALLY IN THE MID 40S,  
FOLLOWED BY LOWS SUNDAY NIGHT IN THE 20S AND LOW 30S.  
 
A WEAK COLD FRONT APPROACHES ON MONDAY AND PASSES THROUGH THE  
REGION WITHOUT PRECIPITATION, AND WITHOUT COLD AIR ADVECTION  
BEHIND IT. WINDS SHIFT TO THE WEST AND DOWNSLOPING EFFECTS WILL  
ALLOW TEMPERATURES TO WARM INTO THE MID AND UPPER 50S. LOWS  
MONDAY NIGHT WILL BE IN THE 30S AND LOW 40S.  
 

 
   
LONG TERM /TUESDAY THROUGH FRIDAY/
 
 
A PROLONGED PERIOD OF UNSEASONABLY WARM AND UNSETTLED WEATHER  
IS ON TAP FOR THE LONG TERM PERIOD. A DEEP UPPER TROUGH OVER THE  
WEST COAST FOR THE START OF THE WEEK WILL MOVE INTO THE ROCKY  
MOUNTAINS ON TUESDAY. SURFACE LOW PRESSURE DEVELOPS OUT AHEAD OF  
IT, AND A WARM FRONT LIFTS NORTH THROUGH THE EASTERN THIRD OF  
THE U.S. WITH AN UPPER RIDGE ALSO OVER THE EASTERN THIRD OF THE  
U.S., STRONG SOUTHERLY FLOW WILL USHER UNSEASONABLY WARM AIR  
INTO THE REGION. A TIGHT PRESSURE GRADIENT FORMS BETWEEN THE  
APPROACHING LOW AND SURFACE HIGH PRESSURE OFFSHORE. GUSTY  
SOUTHERLY WINDS WILL DEVELOP ACROSS THE REGION TUESDAY THROUGH  
WEDNESDAY.  
 
THE FIRST WARM FRONT LIFTS NORTH THROUGH THE REGION TUESDAY,  
AND RAIN WILL DEVELOP IN THE AFTERNOON WITH ITS PASSAGE. AS THE  
COLD FRONT APPROACHES TUESDAY NIGHT AND WEDNESDAY, RAIN  
CONTINUES. A SURGE OF WARM AIR AHEAD OF THE COLD FRONT WILL PUSH  
TEMPERATURES INTO THE 60S, AND A FEW CLIMATE SITES MAY BREAK  
RECORD HIGHS.  
 
IN TERMS OF THE PASSAGE OF THE COLD FRONT, THE 00Z/24 GFS HAS  
COME MORE IN LINE WITH THE 00Z/24 ECMWF COMPARED TO THE 00Z/23  
GFS AND THE 00Z/23 ECMWF. WITH THE LATEST 00Z RUNS, THE GFS IS  
ONLY ABOUT 6 HOURS SLOWER THAN THE ECMWF, AS COMPARED TO 24 TO  
30 HOURS SLOWER THAT THE 00Z/23 MODELS INDICATED. STRONG COLD  
AIR ADVECTION WILL DEVELOP BEHIND THE FRONT, AND LOWS WEDNESDAY  
NIGHT WILL BE IN THE 30S TO LOW 40S, AND HIGHS ON THURSDAY WILL  
STILL BE ABOVE NORMAL LEVELS, BUT THIS TIME SHOULD BE IN THE 40S  
TO LOW 50S. THERE MAY BE A PERIOD OF RAIN/SNOW MIX AS SHOWERS  
TAPER OFF, BUT RIGHT NOW, NO WIDESPREAD ACCUMULATING SNOW IS  
EXPECTED.  
 
CONDITIONS DRY OUT BY TUESDAY AFTERNOON AS HIGH PRESSURE BUILDS  
INTO THE REGION. HIGH PRESSURE WILL THEN BE OVERHEAD ON FRIDAY  
WITH HIGHS IN THE 40S, WHICH ARE NEAR NORMAL FOR THIS TIME OF  
THE YEAR.  
 

 
   
AVIATION /08Z SATURDAY THROUGH WEDNESDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS...  
 
TODAY...VFR CONDITIONS EXPECTED FOR THE MAJORITY OF THE TIME.  
SCATTERED RAIN AND SNOW SHOWERS IN THE MORNING FROM  
KILG/KMIV/KACY NORTHWARD TO NEAR KPHL AND KRDG. CAN'T RULE OUT  
BRIEF MVFR CONDITIONS DUE TO THE SHOWERS, ESPECIALLY FOR KACY  
AND KMIV. CLEARING SKIES IN THE AFTERNOON FROM WEST TO EAST.  
NORTHWEST WINDS AROUND 10 TO 15 KTS WITH GUSTS UP TO AROUND 20  
KTS. MODERATE CONFIDENCE.  
 
TONIGHT...VFR CONDITIONS EXPECTED. NORTHWEST TO WEST WINDS  
AROUND 5 TO 10 KT. HIGH CONFIDENCE.  
 
OUTLOOK...  
 
SUNDAY THROUGH WEDNESDAY...VFR SUNDAY THROUGH AT LEAST TUESDAY  
MORNING. UNSETTLED CONDITIONS MOVE INTO THE TERMINALS LATE  
TUESDAY THROUGH WEDNESDAY WITH SUB-VFR CONDITIONS. PERIODS OF  
HEAVY RAIN MAY DEVELOP TUESDAY NIGHT THROUGH WEDNESDAY. S TO SW  
FLOW SUNDAY THROUGH MONDAY, THEN STRONG S WINDS WILL DEVELOP  
TUESDAY THROUGH WEDNESDAY AS A COLD FRONT APPROACHES FROM THE  
WEST. MODERATE CONFIDENCE.  
 

 
   
MARINE
 
 
LOW END SCA CONDITIONS EXPECTED THROUGH TONIGHT ON THE OCEAN  
WATERS. SEAS 4 TO 6 FEET.  
 
WAVES ARE EXPECTED TO BE 1 TO 3 FEET ON THE DELAWARE BAY,  
HIGHEST ACROSS THE LOWER BAY AND BAYMOUTH.  
 
NORTHWEST WINDS 10 TO 15 KTS WITH OCCASIONAL GUSTS UP TO ABOUT  
20 KTS ACROSS ALL WATERS.  
 
OUTLOOK...  
 
SUNDAY THROUGH WEDNESDAY...SUB-SCA CONDITIONS SUNDAY THROUGH  
EARLY TUESDAY. A COLD FRONT APPROACHES FROM THE WEST AND A TIGHT  
S PRESSURE GRADIENT DEVELOPS TUESDAY AFTERNOON THROUGH  
WEDNESDAY. A SCA WILL LIKELY BE NEEDED, AND GALES ARE POSSIBLE  
AS WELL TUESDAY NIGHT THROUGH WEDNESDAY. VSBY RESTRICTIONS IN  
RAIN AND FOG TUESDAY THROUGH WEDNESDAY.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ450>455.  
 

 
 

 
 
SYNOPSIS...MPS  
NEAR TERM...KRUZDLO  
SHORT TERM...MPS  
LONG TERM...MPS  
AVIATION...KRUZDLO/MPS  
MARINE...KRUZDLO/MPS  
 
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