104  
FNUS71 KLWX 011142  
FWSLWX  
 
SPOT FORECAST FOR JOINT BASE ANDREWS...MD DNR FOREST SERVICE  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
742 AM EDT FRI SEP 1 2017  
 
FORECAST IS BASED ON IGNITION TIME OF 0800 EDT ON SEPTEMBER 01.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION
 
 
A COLD FRONT WILL STALL SOUTH OF THE AREA TODAY WHILE HIGH  
PRESSURE BUILDS ACROSS THE GREAT LAKES. LOW PRESSURE, THE MUCH-  
WEAKENED REMNANTS OF HURRICANE HARVEY, WILL TRACK INTO THE OHIO  
VALLEY TONIGHT, THEN TRANSFER TO THE MID-ATLANTIC COAST BY  
SATURDAY EVENING. OCCASIONAL RAIN, LOW CLOUDS, AND CHILLY  
TEMPERATURES CAN BE EXPECTED THROUGH THIS PERIOD.  
 
WEAK HIGH PRESSURE WILL RETURN LATER SUNDAY THROUGH EARLY NEXT  
WEEK BEFORE ANOTHER FRONT APPROACHES MID-WEEK.  
   
REST OF TODAY
 
 
SKY/WEATHER.........MOSTLY CLOUDY (75-85 PERCENT). ISOLATED SHOWERS  
LATE.  
CWR.................10 PERCENT, INCREASING TO 20 PERCENT.  
MAX TEMPERATURE.....AROUND 69.  
MIN HUMIDITY........45 PERCENT.  
WIND (20 FT)........NORTHEAST WINDS 6 TO 8 MPH.  
MIXING HEIGHT.......1900-3200 FT AGL.  
TRANSPORT WINDS.....NORTHEAST 7 TO 16 MPH, DECREASING TO AROUND 6  
MPH LATE.  
SMOKE DISPERSAL.....FAIR TO GOOD (14900-36300 KNOT-FT).  
 
TIME (EDT) 8 AM 10 AM NOON 2 PM 4 PM  
SKY (%).........86 82 80 77 82  
WEATHER COV..... ISOLTD  
WEATHER TYPE....NONE NONE NONE NONE RNSHWR  
CWR.............0 0 10 10 20  
TEMP............62 62 65 69 68  
RH..............72 65 54 47 47  
20 FT WIND......N 8 NE 8 NE 7 NE 6 NE 6  
20 FT WIND GUST.13 14 12 10 7  
MIX HGT (FT)....1900 2600 3200 3200 3100  
MIXNG WIND......NE 16 NE 15 NE 13 NE 9 NE 7  
VRATE KT-FT/100026 34 35 25 19  
   
TONIGHT
 
 
SKY/WEATHER.........CLOUDY (85-95 PERCENT). A SLIGHT CHANCE OF RAIN  
EARLY IN THE EVENING, THEN A CHANCE OF RAIN  
LATE IN THE EVENING. RAIN AFTER MIDNIGHT.  
CWR.................20 PERCENT, INCREASING TO 80 PERCENT.  
MIN TEMPERATURE.....AROUND 57.  
MAX HUMIDITY........96 PERCENT.  
WIND (20 FT)........EAST WINDS 5 TO 6 MPH.  
MIXING HEIGHT.......900-2800 FT AGL, DECREASING TO 600-2100 FT AGL  
LATE IN THE EVENING, THEN INCREASING TO  
1500-2700 FT AGL AFTER MIDNIGHT.  
TRANSPORT WINDS.....EAST 6 TO 14 MPH, INCREASING TO 16 TO 20 MPH  
LATE.  
SMOKE DISPERSAL.....POOR TO GOOD (4500-35500 KNOT-FT).  
 
TIME (EDT) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM  
SKY (%).........83 81 86 90 100 100  
WEATHER COV.....S CHC CHANCE CHANCE CHANCE LIKELY LIKELY  
WEATHER TYPE....RAIN RAIN RAIN RAIN RAIN RAIN  
CWR.............20 30 30 50 70 70  
TEMP............66 61 59 59 58 58  
RH..............50 70 72 75 83 83  
20 FT WIND......NE 6 E 5 E 4 E 5 E 6 E 6  
20 FT WIND GUST.7 8 7 6 7 7  
MIX HGT (FT)....2800 2200 900 1200 2700 2000  
MIXNG WIND......E 6 E 8 E 8 E 9 E 14 E 18  
VRATE KT-FT/100014 16 7 10 33 32  
   
SATURDAY
 
 
SKY/WEATHER.........CLOUDY (90-100 PERCENT). RAIN. A SLIGHT CHANCE  
OF THUNDERSTORMS IN THE AFTERNOON.  
CWR.................80 PERCENT, DECREASING TO 70 PERCENT IN THE  
MORNING.  
MAX TEMPERATURE.....AROUND 67.  
MIN HUMIDITY........83 PERCENT.  
WIND (20 FT)........EAST WINDS 6 TO 11 MPH. GUSTY AND ERRATIC WINDS  
EXPECTED NEAR THUNDERSTORMS EARLY IN THE  
AFTERNOON.  
MIXING HEIGHT.......800-1400 FT AGL.  
TRANSPORT WINDS.....EAST 13 TO 22 MPH, DECREASING TO AROUND 12 MPH  
LATE.  
SMOKE DISPERSAL.....POOR TO FAIR (8300-26800 KNOT-FT).  
 
TIME (EDT) 6 AM 9 AM NOON 3 PM  
SKY (%).........99 97 95 93  
WEATHER COV.....DEFNTE LIKELY LIKELY LIKELY  
WEATHER TYPE....RAIN RAIN RAIN RNSHWR  
CWR.............80 70 70 70  
TEMP............58 57 60 64  
RH..............86 96 96 93  
20 FT WIND......E 6G7 E 8G12 E 11G16 E 10G14  
MIX HGT (FT)....1400 1400 1300 1100  
MIXNG WIND......E 21 E 22 E 17 E 12  
VRATE KT-FT/100025 26 19 11  
 

 
FORECASTER...SILVERMAN  
REQUESTED BY...CHRIS ROBERTSON  
TYPE OF REQUEST...PRESCRIBED  
.TAG 1715261.0/LWX  
 
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