418  
FNUS71 KPHI 250255  
FWSPHI  
 
SPOT FORECAST FOR DARRONES RX...NATIONAL PARK SERVICE  
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ  
1055 PM EDT TUE APR 24 2018  
 
FORECAST IS BASED ON IGNITION TIME OF 2300 EDT ON APRIL 24.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
 
PLEASE CONTACT OUR OFFICE IF YOU HAVE QUESTIONS OR CONCERNS WITH  
THIS FORECAST.  
   
DISCUSSION
 
 
AN AREA OF LOW PRESSURE LOCATED NEAR THE CAROLINAS WILL CONTINUE TO  
MOVE NORTHWARD ACROSS THE EASTERN SEABOARD, CROSSING OUR AREA  
WEDNESDAY INTO WEDNESDAY NIGHT, THEN INTO NEW ENGLAND BY THURSDAY.  
VERY WEAK HIGH PRESSURE TRIES TO BUILD INTO THE REGION THURSDAY,  
BEFORE ANOTHER LOW PRESSURE MOVES NORTHWARD ACROSS THE EAST COAST  
FRIDAY AND INTO NEW ENGLAND SATURDAY AS IT COMBINES WITH ANOTHER LOW  
PRESSURE. A COLD FRONT IS EXPECTED SATURDAY, WITH ADDITIONAL SURFACE  
TROUGHS SUNDAY INTO MONDAY. HIGH PRESSURE ACROSS THE GREAT LAKES AND  
OHIO VALLEY SUNDAY WILL BUILD TO OUR SOUTH MONDAY INTO TUESDAY.  
   
REST OF TONIGHT
 
 
SKY/WEATHER.........CLOUDY (95-100 PERCENT). RAIN LIKELY LATE IN  
THE EVENING, THEN RAIN AFTER MIDNIGHT.  
CWR.................70 PERCENT INCREASING TO 100 PERCENT.  
CHANCE OF PCPN......100 PERCENT.  
LAL.................NO TSTMS.  
MIN TEMPERATURE.....AROUND 45.  
MAX HUMIDITY........93 PERCENT.  
WIND SHIFT..........NONE EXPECTED.  
WIND (20 FT)........EAST WINDS 6 TO 8 MPH.  
MIXING HEIGHT.......700-800 FT AGL.  
TRANSPORT WINDS.....EAST 10 TO 13 MPH.  
 
TIME (EDT) 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........100 100 100 100 100 100 100  
WEATHER COV.....LKY DEF DEF DEF DEF DEF DEF  
WEATHER TYPE....RN RN RN RN RN RN RN  
TSTM COV........  
CWR.............70 80 90 90 100 100 100  
CHC OF PCPN (%).70 80 90 90 100 100 100  
LAL.............1 1 1 1 1 1 1  
TEMP............51 50 49 48 47 47 47  
RH..............68 74 80 86 93 93 93  
20 FT WIND DIR..E E E E E E E  
20 FT WIND SPD..8 7 6 6 6 7 7  
20 FT WIND GUST.10 10 8 7 8 8 10  
MIX HGT (KFT)...0.8 0.8 0.8 0.8 0.8 0.8 0.7  
TRANSP WIND DIR.SE SE SE E E E E  
TRANSP WIND SPD.10 10 10 10 10 10 13  
   
WEDNESDAY
 
 
SKY/WEATHER.........CLOUDY (85-95 PERCENT). RAIN IN THE MORNING,  
THEN RAIN LIKELY EARLY IN THE AFTERNOON. CHANCE  
OF RAIN EARLY IN THE AFTERNOON.  
CWR.................100 PERCENT DECREASING TO 50 PERCENT.  
CHANCE OF PCPN......100 PERCENT.  
LAL.................NO TSTMS.  
MAX TEMPERATURE.....AROUND 58.  
MIN HUMIDITY........77 PERCENT.  
WIND SHIFT..........WIND SHIFT TO THE NORTH POSSIBLE LATE.  
WIND (20 FT)........NORTHEAST WINDS 6 TO 8 MPH.  
MIXING HEIGHT.......600-1400 FT AGL.  
TRANSPORT WINDS.....EAST 10 TO 14 MPH.  
 
TIME (EDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........100 100 100 96 93 89 86 83 80 81 81 82  
WEATHER COV.....DEF DEF DEF DEF DEF DEF LKY LKY CHC CHC CHC CHC  
WEATHER TYPE....RN RN RN RN RN RN RN RN RN RN RN RN  
TSTM COV........  
CWR.............100 100 90 90 90 80 70 60 50 50 50 50  
CHC OF PCPN (%).100 100 90 90 90 80 70 60 50 50 50 50  
LAL.............1 1 1 1 1 1 1 1 1 1 1 1  
TEMP............47 48 48 50 51 53 54 55 57 57 57 58  
RH..............96 93 93 89 89 86 86 86 80 80 80 77  
20 FT WIND DIR..E E E E E E E E E E NE NE  
20 FT WIND SPD..8 8 8 8 7 7 6 6 6 6 6 6  
20 FT WIND GUST.10 10 10 10 10 8 8 8 7 7  
MIX HGT (KFT)...0.7 0.7 0.6 0.6 0.6 0.7 0.7 0.7 0.8 0.8 0.8 1.4  
TRANSP WIND DIR.E E E E E E E E E E E E  
TRANSP WIND SPD.13 13 14 14 14 13 13 13 10 10 10 10  
   
WEDNESDAY NIGHT
 
 
SKY/WEATHER.........MOSTLY CLOUDY (80-90 PERCENT). CHANCE OF RAIN  
SHOWERS, THEN SLIGHT CHANCE OF RAIN SHOWERS  
EARLY IN THE MORNING.  
CWR.................50 PERCENT DECREASING TO 20 PERCENT.  
CHANCE OF PCPN......50 PERCENT.  
LAL.................NO TSTMS.  
MIN TEMPERATURE.....AROUND 45.  
MAX HUMIDITY........96 PERCENT.  
WIND SHIFT..........WINDS SHIFT TO THE NORTHWEST LATE IN THE EVENING.  
WIND (20 FT)........NORTH WINDS 5 TO 6 MPH EARLY IN THE EVENING  
BECOMING LIGHT, THEN BECOMING NORTHWEST 5 TO 6  
MPH AFTER MIDNIGHT.  
MIXING HEIGHT.......800-1600 FT AGL.  
TRANSPORT WINDS.....NORTHEAST 1 TO 10 MPH SHIFTING TO THE NORTHWEST  
LATE IN THE EVENING, THEN INCREASING TO 17 TO  
18 MPH AFTER MIDNIGHT.  
 
TIME (EDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM  
SKY (%).........83 84 84 87 90 93 90 87 85 82 79 75  
WEATHER COV.....CHC CHC CHC CHC CHC CHC CHC CHC CHC CHC CHC SCH  
WEATHER TYPE....RW RW RW RW RW RW RW RW RW RW RW RW  
TSTM COV........  
CWR.............50 50 50 50 50 50 50 50 30 30 30 20  
CHC OF PCPN (%).50 50 50 50 50 50 50 50 30 30 30 20  
LAL.............1 1 1 1 1 1 1 1 1 1 1 1  
TEMP............57 57 56 55 54 52 51 50 48 47 46 45  
RH..............77 77 77 80 83 89 89 89 93 93 93 96  
20 FT WIND DIR..NE NE N N N NW NW N N NW NW NW  
20 FT WIND SPD..6 6 6 5 3 3 3 3 5 5 5 6  
20 FT WIND GUST. 6 4 4 4 4 6 6 6  
MIX HGT (KFT)...1.4 1.4 1.2 1.2 1.2 0.8 0.8 0.8 1.5 1.5 1.5 1.6  
TRANSP WIND DIR.E E NE NE NE NW NW NW NW NW NW NW  
TRANSP WIND SPD.10 10 1 1 1 5 5 5 17 17 17 18  
   
THURSDAY
 
 
SKY/WEATHER.........PARTLY SUNNY (45-55 PERCENT). SLIGHT CHANCE OF  
RAIN SHOWERS EARLY IN THE MORNING.  
CWR.................20 PERCENT DECREASING TO 10 PERCENT EARLY IN  
THE MORNING.  
CHANCE OF PCPN......20 PERCENT.  
LAL.................NO TSTMS.  
MAX TEMPERATURE.....AROUND 64.  
MIN HUMIDITY........34 PERCENT.  
WIND SHIFT..........NONE EXPECTED.  
WIND (20 FT)........NORTHWEST WINDS 6 TO 9 MPH.  
MIXING HEIGHT.......1600-2900 FT AGL INCREASING TO 4000-4100 FT AGL  
EARLY IN THE AFTERNOON.  
TRANSPORT WINDS.....NORTHWEST 14 TO 18 MPH.  
 
TIME (EDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM  
SKY (%).........64 53 42 42 41 40 40 39 39 41 43 45  
WEATHER COV.....SCH SCH  
WEATHER TYPE....RW RW  
TSTM COV........  
CWR.............20 20 10 10 10 10 10 10 0 0 0 0  
CHC OF PCPN (%).20 20 10 10 10 10 10 10 0 0 0 0  
LAL.............1 1 1 1 1 1 1 1 1 1 1 1  
TEMP............46 46 48 50 52 55 57 59 61 63 64 64  
RH..............93 89 83 74 63 55 49 44 39 36 35 34  
20 FT WIND DIR..NW NW NW NW NW NW NW NW NW NW NW NW  
20 FT WIND SPD..6 6 7 7 8 9 9 9 9 8 7 6  
20 FT WIND GUST. 7 10 10 10 12 12 12 12 10 10 7  
MIX HGT (KFT)...1.6 1.6 1.9 1.9 1.9 2.9 2.9 2.9 4.1 4.1 4.1 4.0  
TRANSP WIND DIR.NW NW NW NW NW NW NW NW NW NW NW W  
TRANSP WIND SPD.18 18 17 17 17 17 17 17 17 17 17 14  
 

 
FORECASTER...SILVA  
REQUESTED BY...MATT BOSS  
TYPE OF REQUEST...PRESCRIBED  
.TAG 1807477.3/PHI  
.EMAIL MATT_BOSS@NPS.GOV  
 
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