665  
FXUS61 KPHI 160702  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
302 AM EDT THU OCT 16 2025  
   
SYNOPSIS
 
 
HIGH PRESSURE ACROSS THE MIDWEST AND GREAT LAKES TODAY WILL  
GRADUALLY SHIFT EASTWARD, THEN SETTLE OVER OUR AREA FRIDAY NIGHT AS  
IT WEAKENS. AS THE HIGH QUICKLY SHIFTS OFFSHORE INTO THE WEEKEND, A  
STRONG COLD FRONT CROSSES OUR AREA SUNDAY NIGHT INTO MONDAY. HIGH  
PRESSURE BUILDS IN FOR TUESDAY, THEN ANOTHER COLD FRONT MAY ARRIVE  
ON WEDNESDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
HIGH PRESSURE CENTERED OVER THE GREAT LAKES WILL CONTINUE TO BUILD  
INTO THE REGION, HELPING KEEP SKIES CLEAR THROUGH THE DAY. WINDS  
FROM THE NNW WILL BE RATHER GUSTY, HOWEVER, AS THE HIGH PRESSES  
AGAINST AN OFFSHORE LOW DEEPENING WELL OFF THE COAST OF NEW ENGLAND.  
THIS RESULTS IN A TIGHTENING PRESSURE GRADIENT OVER THE AREA WHERE  
GUSTS BETWEEN 25-35 MPH ARE POSSIBLE, ESPECIALLY IN THE AFTERNOON.  
GUSTY NNW WINDS WILL ALSO USHER IN A COOLER AND DRIER AIRMASS WITH  
AFTERNOON HIGHS IN THE MID 50S TO LOW 60S AND DEW POINTS FALLING  
INTO THE MID 20S TO LOW 30S. RESULTANT MINIMUM RH% VALUES WILL BE IN  
THE UPPER 20S TO MID 30S, BUT CONCERN OF DRY FUELS REMAINS LOW AT  
THIS TIME AND THEREFORE, FIRE WEATHER CONCERNS REMAIN ON THE LOW END  
AS WELL.  
 
TONIGHT, SKIES REMAIN CLEAR WITH NNW WINDS DIMINISHING, BUT  
REMAINING ELEVATED, AROUND 5-10 MPH. THIS BREEZE IS EXPECTED TO  
PREVENT STRONG RADIATIONAL COOLING ACROSS THE AREA TONIGHT, THOUGH  
SOME SHELTERED LOCATIONS MAY RADIATE BETTER LOCALLY. OVERNIGHT LOWS  
ARE EXPECTED IN THE MID 30S TO LOW 40S. THE GROWING SEASON HAS ENDED  
FOR THE POCONO PLATEAU, LEHIGH VALLEY, AND NORTHWESTERN NJ. OUTSIDE  
OF THOSE LOCATIONS, TEMPERATURES AND WINDS ARE CURRENTLY EXPECTED TO  
REMAIN HIGHER THAN PREFERRED FOR FROST DEVELOPMENT, THUS NO ADVISORY  
HAS BEEN ISSUED AT THIS TIME.  
 

 
   
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
 
 
A LARGE CLOSED LOW ACROSS THE WESTERN ATLANTIC, CENTERED WELL EAST  
OF OUR AREA, IS FORECAST TO GRADUALLY SHIFT EASTWARD FRIDAY AND  
SATURDAY. THIS WILL GRADUALLY END THE CYCLONIC FLOW ACROSS OUR  
REGION, ESPECIALLY AS A NARROW RIDGE ALOFT BEGINS TO ARRIVE FROM THE  
WEST FRIDAY NIGHT AND ESPECIALLY SATURDAY. THIS WILL DELIVER SURFACE  
HIGH PRESSURE MORE RIGHT OVER OUR AREA FRIDAY NIGHT INTO SATURDAY  
BEFORE IT ALREADY STARTS TO SHIFT OFFSHORE. A COOL DAY ONCE AGAIN  
FRIDAY WITH A NORTHERLY BREEZE, HOWEVER AS THE AXIS OF THE SURFACE  
HIGH BEGINS TO SETTLE IN FRIDAY NIGHT THE WINDS SHOULD DECOUPLE IN  
MANY PLACES. WHILE THE AIR MASS WILL START TO MODERATE ALOFT, A  
RATHER DRY AIR MASS COUPLED WITH LITTLE TO NO WIND AND A CLEAR SKY  
SHOULD RESULT IN EFFICIENT RADIATIONAL COOLING. THE FORECAST  
CHALLENGE IS HOW COLD DOES IT GET OUTSIDE OF THE URBAN CENTERS. AT  
LEAST SOME FROST IS CERTAINLY POSSIBLE IN SOME AREAS, HOWEVER THIS  
WILL DEPEND ON THE WIND BECOMING CALM FOR MOST OF THE NIGHT WITH NO  
WARM AIR ADVECTION IMPACTING THE NEAR-SURFACE LAYER.  
 
THE AFOREMENTIONED NARROW RIDGE ALOFT IS FORECAST TO QUICKLY SHIFT  
OFFSHORE DURING SATURDAY, TAKING SURFACE HIGH PRESSURE WITH IT. THIS  
IS IN RESPONSE TO A SHARPENING UPPER-LEVEL TROUGH ACROSS THE MIDWEST  
AND PLAINS. A RETURN FLOW WILL START TO OCCUR BY LATER SATURDAY WITH  
WARM AIR ADVECTION EVENTUALLY STRENGTHENING. SOME INCREASE IN AT  
LEAST SOME HIGH CLOUDS SHOULD OCCUR WELL AHEAD OF THE AFOREMENTIONED  
TROUGH, AND ALSO THE DEVELOPMENT OF A WEAK WARM FRONT. AFTERNOON  
HIGH TEMPERATURES ON SATURDAY ARE FORECAST TO BE AT LEAST A COUPLE  
DEGREES WARMER THAN FRIDAY. AS THE WARM AIR ADVECTION CONTINUES  
SATURDAY NIGHT ALONG WITH SOME ADDITIONAL CLOUDS, TEMPERATURES ARE  
FORECAST TO BE NOTICEABLY MILDER COMPARED TO THE PREVIOUS COUPLE OF  
NIGHTS.  
 

 
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/
 
 
SUMMARY...STRONG COLD FRONT MOVES THROUGH LATER SUNDAY, THEN COOLER  
AND SOME DRIER AIR FOLLOWS. ANOTHER COLD FRONT ARRIVES WEDNESDAY.  
 
SYNOPTIC OVERVIEW...A STRONG UPPER-LEVEL TROUGH IS FORECAST TO CROSS  
THE NORTHEAST AND MID-ATLANTIC REGIONS SUNDAY NIGHT AND MONDAY. THIS  
DRIVES SURFACE LOW PRESSURE ACROSS THE GREAT LAKES TO ADJACENT CANADA  
WITH ITS STRONG COLD FRONT CROSSING OUR AREA SUNDAY NIGHT. THE LOW  
MAY OCCLUDE WITH A SECONDARY LOW DEVELOPING ALONG THE TRIPLE POINT  
NEAR OUR AREA AS THE TROUGH ALOFT MAY TAKE ON A NEGATIVE TILT. A  
NARROW RIDGE ALOFT SLIDES ACROSS OUR AREA TUESDAY, THEN ANOTHER  
UPPER-LEVEL TROUGH MAY ARRIVE ON WEDNESDAY ALONG WITH AN ASSOCIATED  
COLD FRONT.  
 
FOR SUNDAY AND MONDAY...A STRONG UPPER-LEVEL TROUGH IS FORECAST TO  
SLIDE ACROSS THE REGION DURING THIS TIME FRAME. WHILE MOST OF THE  
GUIDANCE IS IN GOOD AGREEMENT WITH THE ARRIVAL OF THIS TROUGH, THERE  
ARE SOME TIMING AND STRENGTH DIFFERENCES. MANY OF THE GFS ENSEMBLE  
MEMBERS SHOULD THIS TROUGH TAKING ON A NEGATIVE TILT AS IT LIFTS  
ACROSS THE NORTHEAST AND MID-ATLANTIC REGIONS. GIVEN THE POTENTIAL  
STRENGTH OF THIS TROUGH, SOUTHERLY FLOW WILL INCREASE AHEAD OF IT  
AND THAT WILL PEAK THE WARM AIR ADVECTION WITH MANY AREAS GETTING  
INTO THE 70S ON SUNDAY DESPITE AN INCREASE IN CLOUD COVER. THE  
OVERALL MOISTURE RETURN MAY BE SOMEWHAT LIMITED AND THAT WOULD  
HINDER INSTABILITY. A LATER TIMING OF THE COLD FRONT (SUNDAY NIGHT)  
IS ALSO NOT IDEAL FOR MAXIMIZED INSTABILITY. SOME GUIDANCE ALSO  
HINTING THAT LOW PRESSURE IN THE GREAT LAKES MAY OCCLUDE WITH A  
SECONDARY LOW DEVELOPING ALONG THE TRIPLE POINT NEAR OUR AREA. IF  
THIS WOULD TO OCCUR, FORCING FOR ASCENT WOULD BE ENHANCED. AS OF  
NOW, LOOKS LIKE AT LEAST A BAND OF SHOWERS ARRIVE AHEAD OF AND WITH  
THE COLD FRONT MOSTLY SUNDAY NIGHT. WHILE SOME THUNDER CANNOT BE  
RULED OUT, THIS WILL BE HIGHLY DEPENDENT ON THE TIMING AND HOW MUCH  
MOISTURE/INSTABILITY IS AVAILABLE. SOME GUIDANCE HAS THE SOUTHERLY  
FLOW AT 925 MB INCREASING TO 40 KNOTS WHICH WOULD INCREASE THE  
LOW TO MID LEVEL SHEAR AHEAD OF THE COLD FRONT. THE FRONT SHIFTS  
TO OUR EAST TO START MONDAY WITH COOLER AND DRIER AIR IN ITS  
WAKE. SOME LINGERING CYCLONIC FLOW AND COLDER AIR ALOFT HOWEVER  
COULD KEEP A FEW SHOWERS GOING THROUGH MONDAY.  
 
FOR TUESDAY AND WEDNESDAY...A NARROW MID LEVEL RIDGE LOOKS TO SLIDE  
ACROSS OUR AREA TUESDAY ALONG WITH SURFACE HIGH PRESSURE TRACKING TO  
OUR SOUTH. THIS SHOULD RESULT IN MOSTLY DRY CONDITIONS AND AFTERNOON  
HIGH TEMPERATURES TUESDAY IN THE MID TO UPPER 60S FOR MOST. THE NEXT  
UPPER-LEVEL TROUGH FROM THE MIDWEST AND GREAT LAKES TO ADJACENT  
CANADA SHIFTS EASTWARD WEDNESDAY WITH A COLD FRONT CROSSING OUR  
AREA. SOME GUIDANCE IS A BIT FASTER WITH THIS, WITH THE COLD FRONT  
ARRIVING TUESDAY NIGHT. THE PARENT LOW MAY TRACK RATHER FAR TO OUR  
NORTH WITH THE UPPER-LEVEL TROUGH CENTER, THEREFORE IT IS MORE  
UNCERTAIN ON THE DETAILS FOR OUR AREA REGARDING PRECIPITATION  
CHANCES.  
 

 
   
AVIATION /06Z THURSDAY THROUGH MONDAY/
 
 
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,  
KILG, KMIV, KACY AND SURROUNDING AREAS.  
 
EARLY THIS MORNING (THROUGH 12Z)...VFR/SKC. NORTH-NORTHWEST WINDS  
AROUND 5-10 KT. HIGH CONFIDENCE.  
 
TODAY...VFR/SKC. NORTH-NORTHWEST WINDS AROUND 10-15 KT WITH  
GUSTS 20 TO 30 KT IN THE AFTERNOON. HIGH CONFIDENCE.  
 
TONIGHT...VFR. NORTHWEST WINDS AROUND 10 KT. HIGH CONFIDENCE.  
 
OUTLOOK...  
 
FRIDAY AND SATURDAY...VFR.  
 
SUNDAY AND MONDAY...SUB-VFR CONDITIONS PROBABLE SUNDAY NIGHT INTO  
MONDAY DUE TO SOME SHOWERS AND LOW CLOUDS. SOUTHERLY WINDS MAY GUST  
TO AROUND 25 KNOTS DURING THE DAY SUNDAY.  
 

 
   
MARINE
 
 
SMALL CRAFT ADVISORY IN EFFECT FOR ALL MARINE ZONES THROUGH THURSDAY  
NIGHT. NORTH-NORTHWEST WINDS 20-25 KTS WITH GUSTS UP TO 30 KTS AND  
SEAS 5-7 FEET. FAIR WEATHER OUTSIDE OF SCA CONDITIONS.  
 
OUTLOOK...  
 
FRIDAY....THE WINDS AND SEAS WILL GRADUALLY SUBSIDE, HOWEVER A SMALL  
CRAFT ADVISORY REMAINS IN EFFECT TO COVER THE LINGERING GUSTY WINDS  
AND ELEVATED SEAS.  
 
SATURDAY...THE CONDITIONS SHOULD BE BELOW SMALL CRAFT ADVISORY  
CRITERIA.  
 
SUNDAY AND MONDAY...SMALL CRAFT ADVISORY CONDITIONS PROBABLE AS A  
STRONG COLD FRONT ARRIVES. STRENGTHENING SOUTHERLY WINDS AHEAD OF  
THE COLD FRONT (GUSTS TO AROUND 30 KNOTS) FOLLOWED BY A WIND SHIFT  
TO THE WEST AND NORTHWEST IN THE WAKE OF THE FRONT. SEAS BUILD ON  
THE OCEAN TO 5-7 FEET WITHIN THE SOUTHERLY FLOW.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NJ...NONE.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT FRIDAY FOR ANZ430-431.  
SMALL CRAFT ADVISORY UNTIL NOON EDT FRIDAY FOR ANZ450.  
SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR ANZ451>455.  
 

 
 

 
 
SYNOPSIS...GORSE  
NEAR TERM...MJL  
SHORT TERM...GORSE  
LONG TERM...GORSE  
AVIATION...GORSE/MJL  
MARINE...GORSE/MJL  
 
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