367  
FNUS71 KPHI 201032  
FWSPHI  
 
SPOT FORECAST FOR SGL 280 BLUE MARSH...PA GAME COMMISSION  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
632 AM EDT TUE APR 20 2021  
 
FORECAST IS BASED ON IGNITION TIME OF 0700 EDT ON APRIL 20.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
 
PLEASE CONTACT OUR OFFICE IF YOU HAVE QUESTIONS OR CONCERNS WITH THIS FORECAST.  
   
DISCUSSION
 
 
WINDS WILL INCREASE OUT OF THE SOUTHWEST TODAY, BECOMING AROUND  
10 TO 15 MPH WITH OCCASIONAL GUSTS TO 20 MPH OR SO. THOUGH DEW  
POINTS ARE EXPECTED TO BE INCREASING WITH TIME, THE STRONG  
HEATING AND INCREASING WINDS MAY ACT TO MIX OUT THE HIGHER  
MOISTURE-CONTENT OF THE AIR. MINIMUM RELATIVE HUMIDITY VALUES  
MAY APPROACH OR EVEN FALL BELOW 30 PERCENT THIS AFTERNOON. WE WILL  
COORDINATE WITH FIRE-WEATHER PARTNERS LATER THIS MORNING TO  
DETERMINE IF A SPECIAL WEATHER STATEMENT WILL BE REQUIRED FOR  
PORTIONS OF THE AREA TODAY.  
   
REST OF TODAY
 
 
SKY/WEATHER.........MOSTLY SUNNY (30-40 PERCENT).  
CHANCE OF PCPN......0 PERCENT.  
MAX TEMPERATURE.....AROUND 70.  
MIN HUMIDITY........30 TO 35 PERCENT.  
WIND (20 FT)........LIGHT WINDS BECOMING WEST 5 TO 15 MPH EARLY IN  
THE MORNING.  
MIXING HEIGHT.......300-1600 FT AGL INCREASING TO 5300-6600 FT AGL.  
TRANSPORT WINDS.....WEST 5 TO 15 MPH INCREASING TO 15 TO 25 MPH IN  
THE LATE MORNING AND AFTERNOON.  
 
TIME (EDT) 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........30 31 28 30 37 30 29 28 33 35 42  
WEATHER COV.....  
WEATHER TYPE....  
TSTM COV........  
CHC OF PCPN (%).0 0 0 0 0 0 0 0 0 0 0  
TEMP............45 46 53 58 62 64 65 67 68 68 68  
RH..............86 86 64 53 46 43 41 39 37 37 37  
20 FT WIND DIR..W W W W W W W W W W W  
20 FT WIND SPD..3 5 6 8 10 12 12 12 12 10 9  
20 FT WIND GUST. 6 10 15 20 22 22 22 21 20 17  
MIX HGT (KFT)...0.3 0.3 0.8 1.6 2.8 3.5 4.6 5.3 6.1 6.6 6.4  
TRANSP WIND DIR.SW W W W W W W W SW SW SW  
TRANSP WIND SPD.5 5 6 16 18 20 21 20 20 18 13  
   
TONIGHT
 
 
SKY/WEATHER.........PARTLY CLOUDY (45-55 PERCENT) THEN BECOMING  
MOSTLY CLOUDY (55-65 PERCENT). SLIGHT CHANCE OF  
RAIN SHOWERS OVERNIGHT.  
CHANCE OF PCPN......20 PERCENT.  
MIN TEMPERATURE.....AROUND 51.  
MAX HUMIDITY........80 TO 85 PERCENT.  
WIND (20 FT)........SOUTH OR SOUTHWEST UP TO 10 MPH.  
MIXING HEIGHT.......1500-3300 FT AGL DECREASING TO 500-800 FT AGL  
EARLY IN THE EVENING.  
TRANSPORT WINDS.....SOUTH 5 TO 15 MPH INCREASING TO 10 TO 20 MPH  
OVERNIGHT.  
 
TIME (EDT) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM  
SKY (%).........49 55 62 64 53 64  
WEATHER COV.....  
WEATHER TYPE....NONE NONE NONE NONE NONE NONE  
TSTM COV........  
CHC OF PCPN (%).10 10 10 10 10 10  
TEMP............67 62 57 54 53 52  
RH..............42 54 67 74 77 77  
20 FT WIND......SW 8 S 6 S 6 S 7 S 7 S 8  
20 FT WIND GUST.13 8 8 10 10 12  
MIX HGT (FT)....3300 700 600 600 600 700  
TRANSPORT WIND..SW 13 S 10 S 12 S 16 S 15 S 16  
   
WEDNESDAY
 
 
SKY/WEATHER.........PARTLY TO MOSTLY CLOUDY. RAIN SHOWERS  
LIKELY WITH A CHANCE OF THUNDERSTORMS,  
ESPECIALLY IN THE LATE MORNING IN THE MID  
AFTERNOON.  
CHANCE OF PCPN......70 PERCENT.  
MAX TEMPERATURE.....AROUND 63.  
MIN HUMIDITY........55 TO 60 PERCENT.  
WIND (20 FT)........SOUTH WINDS 10 TO 20 MPH SHIFTING TO THE WEST 15  
TO 25 MPH WITH GUSTS TO 35 MPH IN THE  
AFTERNOON. GUSTY AND ERRATIC WINDS EXPECTED  
NEAR THUNDERSTORMS.  
MIXING HEIGHT.......800-2000 FT AGL INCREASING TO 4900 FT AGL.  
TRANSPORT WINDS.....SOUTH 15 TO 25 MPH, THEN SHIFTING TO THE SOUTHWEST  
20 TO 30 MPH LATE IN THE MORNING, SHIFTING TO  
THE WEST 25 TO 35 MPH BY MID AFTERNOON.  
 
TIME (EDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM  
SKY (%).........56 38 51 69 79 55  
WEATHER COV.....CHANCE LIKELY LIKELY LIKELY LIKELY LIKELY  
WEATHER TYPE....RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR  
TSTM COV........ S CHC S CHC S CHC CHANCE CHANCE  
CHC OF PCPN (%).30 60 60 70 60 60  
TEMP............51 55 59 61 56 52  
RH..............80 72 69 65 72 63  
20 FT WIND......S 9 S 10 S 13 SW 14 W 16 W 16  
20 FT WIND GUST.13 21 25 26 29 31  
MIX HGT (FT)....800 1200 2000 4000 2900 4200  
TRANSPORT WIND..S 16 S 20 S 22 SW 26 W 33 NW 33  
 

 
FORECASTER...CMS  
REQUESTED BY...JONATHAN WEAVER  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2109729.0/PHI  
.DELDT 04/20/21  
.EMAIL JONWEAVER@PA.GOV  
 
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