912  
FXUS61 KPHI 181052  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
552 AM EST TUE FEB 18 2025  
   
SYNOPSIS  
 
HIGH PRESSURE BUILDS IN FROM THE WEST BEFORE SLIDING SOUTH AND  
EAST OF THE REGION TUESDAY NIGHT. LOW PRESSURE APPROACHES THE  
MID-ATLANTIC AND MOVES OFFSHORE WEDNESDAY THROUGH THURSDAY.  
HIGH PRESSURE RETURNS FOR THE END OF THE WEEK AND THIS WEEKEND.  
 
 
   
NEAR TERM /THROUGH TONIGHT/  
 
NO MAJOR CHANGES WITH THE MORNING UPDATE. WINDS HAVE DECOUPLED  
IN SOME LOCATIONS, BUT THAT WON'T LAST LONG AFTER SUNRISE AS  
MIXING ONCE AGAIN BECOMES MORE EFFICIENT.  
 
THROUGH EARLY WEDNESDAY MORNING, THE MAIN STORY IS GOING TO BE  
CONTINUED COLD WITH BREEZY (BUT GRADUALLY DIMINISHING) WINDS. A  
SURFACE RIDGE WILL BE BUILDING EASTWARD OVER OUR REGION AND WILL  
BE THE DOMINANT PATTERN FEATURE FOR OUR AREA. THE COMBINATION  
OF THIS RIDGE BUILDING IN LEADING TO A DECREASING SURFACE  
PRESSURE GRADIENT, AND THE LOW AND MID LEVEL JETS FINALLY  
PROGRESSING EASTWARD IS WHAT WILL MAKE THE DIFFERENCE WITH THE  
WINDS FINALLY DIMINISHING ESPECIALLY INTO TONIGHT.  
 
WE COULD ONCE AGAIN GET CLOSE TO COLD WEATHER ADVISORY IMPACTS IN  
THE SOUTHERN POCONOS TUESDAY NIGHT, BUT IF WE GET CLOUDS TO MOVE IN  
EARLY ENOUGH (AHEAD OF THE LOW THAT WILL BE PASSING TO OUR SOUTH  
WEDNESDAY INTO THURSDAY), THEN THAT COULD LIMIT HOW COLD AREAS GET  
TONIGHT.  
 
 
   
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/  
 
AFTER A CHILLY START TO THE DAY WEDNESDAY, CLOUDS WILL START TO  
FILTER IN OVER THE REGION AS HIGH PRESSURE PUSHES OFFSHORE.  
ATTENTION STILL TURNS TO THE DEEPENING UPPER LEVEL CLOSED LOW AS  
IT DIGS SOUTH OF THE GREAT LAKES INTO WEDNESDAY NIGHT  
EVENTUALLY DEVELOPING A SURFACE LOW PRESSURE SYSTEM WELL OUT  
AHEAD OF THE PARENT UPPER LEVEL THROUGH. ENSEMBLE GUIDANCE  
CONTINUES TO INDICATE A SLIGHTLY SOUTHERN SHIFT IN THE CENTER OF  
THE LOW TRACKS RESULTING IN THE BULK OF THE SNOW FALLING OVER  
SOUTHERN PORTIONS OF DELAWARE AND THE EASTERN SHORES OF  
MARYLAND, AND MINIMAL SNOW ACCUMULATIONS FOR THE MAJORITY OF THE  
FORECAST AREA. THE LONE EXCEPTION TO THE REDUCED SNOW TOTALS IS  
THE NAM WHICH DID SLIGHTLY SHIFT NORTH.  
 
WITH THE SLIGHT REDUCTION IN SNOWFALL AMOUNTS HERE AT THE NEW  
ANTICIPATED ACCUMULATIONS FROM WEDNESDAY AFTERNOON THROUGH  
THURSDAY:  
 
LESS THAN AN INCH OVER THE SOUTHERN POCONOS, NORTHERN NEW JERSEY,  
AND THE LEHIGH VALLEY DOWN TO THE I-95 CORRIDOR.  
 
LESS THAN AN INCH FOR THE DELAWARE VALLEY, MOST OF SOUTHERN NEW  
JERSEY AND COASTAL NEW JERSEY.  
 
1 TO 3 INCHES FOR SOUTHERN PORTIONS OF THE EASTERN SHORES OF  
MARYLAND, SOUTHERN DELAWARE, AND EXTREME SOUTHEAST NEW JERSEY.  
 
THE 01Z/18 NBM PROBS CONTINUE TO DOWNPLAY THE POTENTIAL FOR  
SIGNIFICANT SNOW TOTALS WITH ABOUT A 30-35% CHANCE OF 2" OR MORE OF  
SNOW FOR THE JERSEY SHORE SOUTH OF ATLANTIC CITY, AND BETWEEN A 40-  
45% CHANCE OF 2 OR MORE INCHES ACROSS SOUTHEASTERN SUSSEX COUNTY IN  
DE. WITH THAT IN MIND, I'VE OPTED TO KEEP THE WATCH IN PLACE DURING  
THIS MODEL CYCLE DUE TO THE POTENTIAL FOR THE GLOBAL SUITE TO  
PERHAPS TAKE A MORE NORTHERN SHIFT AS SHOWN IN THE NAM. IF THAT DOES  
NOT OCCUR, THEN ADVISORIES WILL BE LIKELY FOR CAPE MAY NJ AND SUSSEX  
DE FOR THE 1-3" OF SNOW WITH NO OTHER HAZARDS ANTICIPATED DUE TO  
SNOW.  
 
THE LOW WILL DEPART THE REGION THURSDAY EVENING AND ANY LINGERING  
SNOW IN NW FLOW STREAMERS SHOULD BE MINIMAL WITH LITTLE ADDITIONAL  
ACCUMULATIONS.  
 
 
   
LONG TERM /FRIDAY THROUGH MONDAY/  
 
BROAD HIGH PRESSURE DEVELOPS IN THE WAKE OF THE DEPARTING SYSTEM AND  
WILL DOMINATE THROUGH THE WEEKEND INTO THE BEGINNING OF THE WORK  
WEEK. THIS WILL LEAD TO A MODERATING OF TEMPERATURES FROM WELL  
BELOW NORMAL ON FRIDAY TO NEAR NORMAL BY MONDAY.  
 
 
   
AVIATION /12Z TUESDAY THROUGH SATURDAY/  
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
THROUGH TODAY...VFR. WEST-NORTHWEST WINDS 15-20 KNOTS WITH  
GUSTS UP TO 30 KNOTS.  
 
TONIGHT...VFR, THOUGH HIGH CLOUDS WILL BE ON THE INCREASE LATE  
TONIGHT. WEST-NORTHWEST WINDS WILL DIMINISH TO NEAR 10 KT BY  
VERY LATE TONIGHT.  
 
OUTLOOK...  
 
WEDNESDAY THROUGH THURSDAY...SUB-VFR CONDITIONS LIKELY IN SN  
FOR KMIV/KACY, AND A SUB-VFR CONDITIONS POSSIBLE IN LIGHT SN  
FOR THE REST OF THE TERMINALS.  
 
THURSDAY NIGHT THROUGH SATURDAY...VFR.  
 
 
   
MARINE  
 
ALL OBSERVATIONS HAVE DROPPED BELOW GALE FORCE, SO THE GALE  
WARNING HAS BEEN CANCELLED. SMALL CRAFT ADVISORY CONDITIONS  
WILL CONTINUE THROUGH AT LEAST THE DAY TIME TODAY, AND ARE  
EXPECTED TO CONTINUE THROUGH THE EVENING FOR THE COASTAL WATERS.  
 
AFTER MIDNIGHT TONIGHT, WE SHOULD SEE A LULL IN ELEVATED WINDS AND  
SEAS ON THE AREA WATERS CONTINUING INTO THE EARLY MORNING ON  
WEDNESDAY.  
 
OUTLOOK...  
 
WEDNESDAY THROUGH WEDNESDAY NIGHT...SUB-SCA CONDITIONS. VSBY  
RESTRICTIONS IN SN POSSIBLE STARTING LATE WEDNESDAY AFTERNOON.  
 
THURSDAY THROUGH THURSDAY NIGHT...SCA DURING THE DAY WITH POSSIBLE  
GALE CONDITIONS THURSDAY NIGHT. VSBY RESTRICTIONS IN SN  
THURSDAY.  
 
FRIDAY THROUGH FRIDAY NIGHT...SCA CONDITIONS, WITH POSSIBLE  
GALE CONDITIONS FOR THE WATERS ACROSS DE AND SOUTHERN NJ  
FRIDAY, SUBSIDING FRIDAY NIGHT.  
 
SATURDAY...SUB-SCA CONDITIONS.  
 
 
   
PHI WATCHES/WARNINGS/ADVISORIES  
 
PA...COLD WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ054-  
055.  
NJ...NONE.  
DE...WINTER STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY  
AFTERNOON FOR DEZ003-004.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ430-  
431.  
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ450>455.  
 
 
 
 
 
SYNOPSIS...MPS  
NEAR TERM...JOHNSON  
SHORT TERM...DEAL/MPS  
LONG TERM...DEAL/MPS  
AVIATION...COOPER/DEAL/JOHNSON  
MARINE...DEAL/JOHNSON  
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