791  
FXUS61 KPHI 171016  
AFDPHI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
616 AM EDT WED OCT 17 2018  
   
SYNOPSIS
 
 
A COLD FRONT WILL CROSS THE MIDDLE ATLANTIC REGION THIS AFTERNOON.  
IT WILL BE FOLLOWED BY HIGH PRESSURE FROM THE OHIO VALLEY WHICH WILL  
BE ACROSS THE AREA THROUGH FRIDAY. ANOTHER LOW PRESSURE SYSTEM AND  
COLD FRONT WILL AFFECT OUR AREA FRIDAY NIGHT AND SATURDAY. MORE HIGH  
PRESSURE WILL MOVE IN FOR THE END OF THE WEEKEND AND INTO EARLY NEXT  
WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
COLD FRONT IS EXPECTED TO ARRIVE LATER TODAY. PRESSURE GRADIENT,  
ESPECIALLY BEHIND THE FRONT WILL INCREASE SIGNIFICANTLY. AS A  
RESULT, EXPECT GUSTY CONDITIONS AND STRONG COLD AIR ADVECTION.  
 
ONE THING WE ARE NOT EXPECTING MUCH OF WITH THIS FRONT IS  
PRECIPITATION. DEW POINTS HAVE DROPPED INTO THE 30S AND 40S ACROSS  
THE REGION AFTER THE COLD FRONT FROM 2 NIGHTS AGO. THERE WILL NOT BE  
ANY SIGNIFICANT MOISTURE ADVECTION TODAY AHEAD OF THE FRONT. THUS,  
PRECIPITATION, IF ANY, WILL BE LIMITED. HAVE KEPT ONLY A SLIGHT  
CHANCE MENTION ACROSS THE SOUTHERN POCONOS AND NW NJ.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/
 
 
BEHIND THE FRONT, EXPECT CONTINUED DRY AND COLD AIR ADVECTION  
OVERNIGHT. CONSEQUENTLY, WE COULD SEE THE FIRST FREEZE OF THE SEASON  
FOR SOME OF OUR AREA. THERE ARE HOWEVER A FEW UNKNOWNS THAT COULD  
HAVE AN IMPACT ON HOW WIDESPREAD THE FREEZE WILL BE. FIRST OF ALL,  
WINDS ARE NOT EXPECTED TO DECOUPLE MUCH OVERNIGHT, BUT RATHER SHOULD  
REMAIN NEAR OR ABOVE 10 MPH. AS A RESULT, WE LIKELY WON'T SEE MUCH  
IN THE WAY OF A FROST. HOWEVER, THIS COULD ALSO LIMIT RADIATIONAL  
COOLING. SECONDLY, IF MID LEVEL CLOUDS THAT ARE EXPECTED THIS  
AFTERNOON WITH THE FRONT ARE SLOWER TO CLEAR OUT, THAT COULD ALSO  
LIMIT RADIATIONAL COOLING.  
 
FREEZING CONDITIONS LOOK TO BE MOST LIKELY IN THE SOUTHERN POCONOS  
WHERE WE HAVE ISSUED A FREEZE WARNING. FOR FAR NW NJ, CONFIDENCE IS  
LOWER, SO HAVE ISSUED A FREEZE WATCH FOR SUSSEX COUNTY. FOR THE REST  
OF NW NJ, LEHIGH VALLEY, AND BERKS COUNTY, WE WILL LIKELY SEE LOWS  
IN THE MID 30S, BUT ARE NOT PLANNING ANY FROST ADVISORY AT THIS TIME  
AS THE WINDS SHOULD PRECLUDE THE DEVELOPMENT OF FROST.  
 
FOR AREAS ALONG AND SOUTHEAST OF THE I95 CORRIDOR, EXPECT LOWS FROM  
THE MID 30S TO LOWER 40S.  
 

 
   
LONG TERM /THURSDAY THROUGH TUESDAY/
 
 
THURSDAY THRU FRIDAY...MOSTLY FAIR THIS PERIOD WITH A RIDGE OF  
HIGH PRESSURE AFFECTING THE REGION. SOME GUSTY WINDS EARLY  
THURSDAY WILL DIMINISH BY AFTERNOON. TEMPERATURES WELL BELOW  
NORMAL THU THEN A LITTLE BELOW NORMAL FOR FRIDAY. INCREASING  
CLOUDS ARE EXPECTED LATER FRIDAY.  
 
FRIDAY NIGHT AND SATURDAY...THE WETTEST PART OF THE LONG TERM  
WITH A LOW PRESSURE SYSTEM MOVING NORTH OF THE AREA AND A COLD  
FRONT EXPECTED TO CROSS THE REGION. POPS WERE RAISED FROM THE  
EARLIER FCST WITH HIGH CHC/LOW LIKELY POPS NOW IN THE GRIDS.  
TEMPERATURES WILL BE CLOSE TO NORMAL SAT WITH HIGHER HUMIDITY  
LEVELS TOO. THE COLD FRONT WILL CROSS THE AREA DURING THE  
AFTERNOON, SO SHOWERS ARE POSSIBLE UNTIL AFTER THE FRONT PASSES.  
GUSTY WINDS ARE POSSIBLE SAT, BUT NOTHING TOO SERIOUS.  
 
SUNDAY THRU TUESDAY...MOSTLY FAIR WEATHER IS EXPECTED THIS  
PERIOD, HOWEVER A COUPLE SHOWERS MAY OCCUR ACROSS THE NORTHERN  
COUNTIES MON NIGHT AND TUESDAY. HIGH PRESSURE FROM THE WEST WILL  
BUILD IN MON AND THE MOVE OFFSHORE TUE. TEMPERATURES WILL BE  
MOSTLY BELOW NORMAL SUN/MON THEN REBOUND BACK TO NEAR NORMAL FOR  
TUE.  
 
NORMAL HIGHS: PHL/MPO/GED : 64/55/66  
NORMAL LOWS : PHL/MPO/GED : 46/34/43  
 

 
   
AVIATION /10Z WEDNESDAY THROUGH SUNDAY/
 
 
TODAY...VFR CONDITIONS EXPECTED. WINDS WILL SHIFT FROM SOUTHWESTERLY  
TO WESTERLY TO WEST NORTHWESTERLY THROUGH THE DAY. GUSTS AROUND 25  
KT OR MORE WILL BE POSSIBLE, PRIMARILY BETWEEN 15 AND 00Z. HIGH  
CONFIDENCE.  
 
TONIGHT...VFR CONDITIONS EXPECTED. NORTHWESTERLY WINDS WILL  
GRADUALLY DIMINISH TO NEAR 10 KT OVERNIGHT. HIGH CONFIDENCE.  
 
OUTLOOK...  
THU THRU FRI...VFR EXPECTED. GUSTY NW WINDS THU MORNING.  
FRI NIGHT/SAT...SUB-VFR POSSIBLE WITH SHOWERS. GUSTY WINDS SAT.  
SAT NIGHT/SUNDAY...VFR EXPECTED. GUSTY WINDS AGAIN SUNDAY.  
 

 
   
MARINE
 
 
UPDATED THE SMALL CRAFT ADVISORY TO BEGIN NOW FOR THE NORTHERN  
AND CENTRAL NJ COASTAL WATERS AS WINDS ARE ALREADY GUSTING TO 25  
KT AT BUOY 44065. OTHERWISE, NO MAJOR CHANGES.  
 
WINDS WILL BE INCREASING, ESPECIALLY THROUGH THE AFTERNOON WITH  
GALE FORCE GUSTS EXPECTED TO DEVELOP BY EARLY THIS EVENING ON  
ALL WATERS EXCEPT THE UPPER DELAWARE BAY. THERE IS A CHANCE THAT  
GALE FORCE GUSTS COULD DEVELOP A FEW HOURS EARLIER, BUT DON'T  
HAVE ENOUGH CONFIDENCE AT THIS TIME TO MOVE UP THE START TIME OF  
THE GALE WARNING. GALE FORCE GUSTS SHOULD CONTINUE FOR MOST, IF  
NOT ALL OF THE OVERNIGHT HOURS. ON THE UPPER DELAWARE BAY,  
EXPECT SMALL CRAFT ADVISORY CONDITIONS THROUGH OUT THE PERIOD.  
 
OUTLOOK...  
THU: EARLY GALES WILL SETTLE TO SCA CONDITIONS THEN DROP BELOW SCA LATER  
THURSDAY. FAIR WEATHER.  
THU NIGHT THRU FRI: SUB-SCA, BUT WINDS INCREASE FRI LATE  
AFTERNOON. FAIR.  
FRI NIGHT THRU SAT. SHOWERS. SCA CONDITIONS EXPECTED.  
SAT NIGHT INTO SUNDAY..A CONTINUATION OF SCA CONDITIONS WITH  
SOME LOW-END GALES POSSIBLE. FAIR WEATHER.  
 

 
   
PHI WATCHES/WARNINGS/ADVISORIES
 
 
PA...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT THURSDAY FOR  
PAZ054-055.  
NJ...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR  
NJZ001.  
DE...NONE.  
MD...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 PM EDT THIS  
EVENING FOR ANZ431-452>455.  
GALE WARNING FROM 6 PM THIS EVENING TO 9 AM EDT THURSDAY FOR  
ANZ452>455.  
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ450-  
451.  
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT THURSDAY FOR  
ANZ431-450-451.  
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 PM EDT  
THURSDAY FOR ANZ430.  
 

 
 

 
SYNOPSIS...O'HARA  
NEAR TERM...JOHNSON  
SHORT TERM...JOHNSON  
LONG TERM...O'HARA  
AVIATION...JOHNSON/O'HARA  
MARINE...JOHNSON/O'HARA  
 
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