FNUS71 KLWX 221605 FWSLWX SPOT FORECAST FOR 1ST MANASSAS...NPS NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1205 PM EDT FRI JUL 22 2011 FORECAST IS BASED ON INCIDENT TIME OF 1148 EDT ON JULY 22. IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER SERVICE. ...EXCESSIVE HEAT WARNING IN EFFECT UNTIL 10 PM EDT THIS EVENING... ...EXCESSIVE HEAT WARNING IN EFFECT FROM 10 AM TO 8 PM EDT SATURDAY... .DISCUSSION... HIGH PRESSURE WILL BRING OPPRESSIVE HEAT TO THE AREA TODAY THROUGH THE WEEKEND. HIGH TEMPERATURES THIS AFTERNOON WILL RISE INTO THE LOWER 100S...WITH AFTERNOON AND EARLY EVENING HEAT INDEX VALUES AROUND 115. TEMPERATURES WILL DROP INTO THE MID TO UPPER 90S BY 8 PM THIS EVENING...BUT HEAT INDEX VALUES WILL STILL BE 105 TO 110 THROUGH MUCH OF THE EVENING. THE HEAT INDEX VALUE MAY NOT DROP BELOW 100 UNTIL AFTER MIDNIGHT TONIGHT. HIGH TEMPERATURES ON SATURDAY WILL RISE TO AROUND 100 DEGREES...WITH HEAT INDEX VALUES IN THE AFTERNOON AND EVENING BETWEEN 110 AND 115. HEAT AND HUMIDITY MAY LEAD TO AFTERNOON AND EVENING SCATTERED THUNDERSTORMS ON SATURDAY. ONE MORE HOT AND HUMID DAY WILL OCCUR ON SUNDAY...WITH HEAT INDEX VALUES UP TO 105 DEGREES POSSIBLE. SCATTERED THUNDERSTORMS ARE POSSIBLE. MORE SEASONABLE TEMPERATURES ARE EXPECTED TO MOVE IN EARLY NEXT WEEK. .REST OF TODAY... SKY/WEATHER.........MOSTLY SUNNY (20-30 PERCENT). MAX TEMPERATURE.....AROUND 103. MIN HUMIDITY........42 PERCENT. WIND (20 FT)........WEST WINDS AROUND 5 MPH EARLY IN THE AFTERNOON...BECOMING LIGHT AND VARIABLE...THEN BECOMING WEST 5 TO 6 MPH LATE. CWR.................10 PERCENT. TIME (EDT) NOON 2 PM 4 PM SKY (%).........19 27 33 WEATHER COV..... WEATHER TYPE....NONE NONE NONE TEMP............98 101 101 RH..............50 44 42 20 FT WIND......W 4 W 3 W 5 20 FT WIND GUST.10 5 10 CWR.............10 10 10 .TONIGHT... SKY/WEATHER.........PARTLY CLOUDY (30-40 PERCENT). A CHANCE OF SHOWERS AND THUNDERSTORMS EARLY IN THE EVENING. MIN TEMPERATURE.....AROUND 79. MAX HUMIDITY........88 PERCENT. WIND (20 FT)........WEST WINDS AROUND 5 MPH EARLY IN THE EVENING...BECOMING LIGHT AND VARIABLE. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS EARLY IN THE EVENING. CWR.................10 PERCENT. TIME (EDT) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM SKY (%).........36 39 38 36 34 34 WEATHER COV..... CHANCE CHANCE WEATHER TYPE....NONE RNSHWR RNSHWR NONE NONE NONE TEMP............99 96 89 85 84 82 RH..............45 53 66 72 74 77 20 FT WIND......W 4 W 2 W 2 W 2 W 2 W 2 20 FT WIND GUST.10 5 5 5 5 5 CWR.............10 30 30 10 10 10 .SATURDAY... SKY/WEATHER.........MOSTLY SUNNY (45-55 PERCENT). A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. MAX TEMPERATURE.....AROUND 101. MIN HUMIDITY........45 PERCENT. WIND (20 FT)........LIGHT AND VARIABLE WINDS...BECOMING WEST AROUND 5 MPH EARLY IN THE AFTERNOON...THEN BECOMING LIGHT AND VARIABLE EARLY IN THE AFTERNOON...BECOMING WEST AROUND 5 MPH LATE. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS EARLY IN THE MORNING. CWR.................10 PERCENT...INCREASING TO 30 PERCENT. TIME (EDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM SKY (%).........38 50 49 47 45 52 WEATHER COV..... S CHC S CHC S CHC CHANCE CHANCE WEATHER TYPE....NONE RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR TEMP............79 85 92 97 99 99 RH..............88 75 58 48 47 48 20 FT WIND......NW 3 NW 2 NW 2 W 3 W 3 W 4 20 FT WIND GUST.5 5 5 5 5 5 CWR.............10 20 20 20 30 30 $$ FORECASTER...PELOQUIN REQUESTED BY...SEABRIGHT TYPE OF REQUEST...SAR .TAG 20110722.1STMA.01/LWX