821  
FNUS71 KPHI 090958  
FWSPHI  
 
SPOT FORECAST FOR JACOBSBURG GRASS FIELDS...PA GAME COMMISSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
558 AM EDT WED SEP 9 2026  
 
FORECAST IS BASED ON IGNITION TIME OF 1000 EDT ON SEPTEMBER 09.  
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL WEATHER  
SERVICE.  
 
PLEASE CONTACT OUR OFFICE IF YOU HAVE QUESTIONS  
OR CONCERNS WITH THIS FORECAST.  
   
DISCUSSION
 
 
HIGH PRESSURE OFF THE MID-ATLANTIC COAST REMAINS IN CONTROL UNTIL IT  
MOVES OUT TO SEA TONIGHT. A COLD FRONT CROSSES THROUGH THE AREA ON  
THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE RETURNS FOR FRIDAY AND  
SATURDAY, FOLLOWED BY ANOTHER DISTURBANCE SATURDAY NIGHT INTO  
SUNDAY. HIGH PRESSURE BUILDS BACK IN EARLY NEXT WEEK.  
   
REST OF TODAY
 
 
SKY/WEATHER.........PARTLY SUNNY (55-65 PERCENT).  
MAX TEMPERATURE.....AROUND 84.  
MIN HUMIDITY........57 PERCENT.  
WIND (20 FT)........LIGHT WINDS BECOMING SOUTHWEST 5 TO 9 MPH LATE  
IN THE MORNING.  
MIXING HEIGHT.......3100 FT AGL.  
TRANSPORT WINDS.....SOUTHWEST 7 TO 16 MPH.  
ADI.................11 TO 42.  
 
TIME (EDT) 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........73 55 62 61 70 68 56 51  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
TEMP............73 76 78 80 81 82 83 83  
RH..............76 69 67 62 60 61 59 57  
20 FT WIND DIR..S SW SW SW SW SW SW SW  
20 FT WIND SPD..3 5 6 7 9 9 9 9  
20 FT WIND GUST.8 12 13 15 16 17 18 18  
MIX HGT (KFT)...1.3 1.6 2.2 2.7 3.1 2.8 3.1 3.1  
TRANSP WIND DIR.S SW SW SW SW SW SW SW  
TRANSP WIND SPD.7 9 10 12 13 14 15 16  
ADI.............11 16 29 35 41 42 37 39  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLOUDY (65-75 PERCENT). SLIGHT CHANCE OF  
SHOWERS OVERNIGHT. CHANCE OF SHOWERS AND SLIGHT  
CHANCE OF THUNDERSTORMS OVERNIGHT.  
MIN TEMPERATURE.....AROUND 68.  
MAX HUMIDITY........90 PERCENT.  
WIND (20 FT)........SOUTHWEST WINDS 7 TO 8 MPH. GUSTY AND ERRATIC  
WINDS EXPECTED NEAR THUNDERSTORMS OVERNIGHT.  
MIXING HEIGHT.......500 FT AGL.  
TRANSPORT WINDS.....SOUTHWEST 12 TO 14 MPH.  
ADI.................10 TO 20.  
 
TIME (EDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........69 61 63 65 63 66 69 64 67 69 78 83  
WEATHER COV..... SCH CHC CHC CHC CHC  
WEATHER TYPE.... RW RW RW RW RW  
TSTM COV........ SCH SCH SCH SCH  
TEMP............81 79 76 75 74 73 73 72 72 71 70 69  
RH..............60 62 64 66 69 68 68 71 71 73 76 81  
20 FT WIND DIR..SW S S SW SW SW SW SW SW SW SW SW  
20 FT WIND SPD..9 8 8 8 8 8 9 9 8 8 9 9  
20 FT WIND GUST.18 16 15 15 16 16 16 15 15 16 17 16  
MIX HGT (KFT)...1.2 0.8 0.8 0.7 0.5 0.5 0.5 0.8 1.0 0.7 0.8 0.6  
TRANSP WIND DIR.S S SW SW SW SW SW SW SW SW W SW  
TRANSP WIND SPD.14 14 13 14 14 14 14 13 13 13 12 12  
ADI.............20 12 11 12 12 12 12 11 11 11 10 10  
   
THURSDAY
 
 
SKY/WEATHER.........PARTLY SUNNY (50-60 PERCENT). CHANCE OF SHOWERS  
EARLY IN THE MORNING. SLIGHT CHANCE OF  
THUNDERSTORMS EARLY IN THE MORNING. SLIGHT  
CHANCE OF SHOWERS EARLY IN THE MORNING.  
MAX TEMPERATURE.....AROUND 84.  
MIN HUMIDITY........58 PERCENT.  
WIND (20 FT)........WEST WINDS 6 TO 8 MPH. GUSTY AND ERRATIC WINDS  
EXPECTED NEAR THUNDERSTORMS EARLY IN THE  
MORNING.  
MIXING HEIGHT.......4900 FT AGL.  
TRANSPORT WINDS.....WEST 10 TO 15 MPH.  
ADI.................7 EARLY IN THE MORNING INCREASING TO 78 IN THE  
AFTERNOON.  
 
TIME (EDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........74 61 56 43 52 63 50 40 48 42 46 38  
WEATHER COV.....CHC SCH  
WEATHER TYPE....RW RW  
TSTM COV........SCH SCH  
TEMP............69 68 70 71 75 77 80 81 82 83 82 81  
RH..............81 87 90 90 82 76 69 65 61 59 58 60  
20 FT WIND DIR..SW SW W W W W W W W W W W  
20 FT WIND SPD..7 7 7 7 8 7 8 8 8 9 9 8  
20 FT WIND GUST.14 12 10 10 10 12 13 14 14 14 13 10  
MIX HGT (KFT)...0.5 0.5 0.7 1.2 1.9 2.9 3.2 3.9 4.4 4.7 4.9 3.7  
TRANSP WIND DIR.W W W W W W W W W W W W  
TRANSP WIND SPD.10 10 10 12 13 14 15 14 15 15 14 15  
ADI.............7 8 11 18 24 43 59 65 78 60 56 67  
 

 
FORECASTER...MPS  
REQUESTED BY...JONATHAN WEAVER  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2621473.0/PHI  
.DELDT 09/09/26  
.FORMATTERVERSION 2.0.0  
.EMAIL JONWEAVER@PA.GOV  
 
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