FNUS71 KAKQ 211138 FWSAKQ SPOT FORECAST FOR PETTIT...VDOF NATIONAL WEATHER SERVICE WAKEFIELD VA 738 AM EDT THU MAY 21 2009 FORECAST IS BASED ON IGNITION TIME OF 1200 EDT ON MAY 21. IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER SERVICE. .DISCUSSION... ...DRY WITH LOW RELATIVE HUMIDITIES OVER INLAND AREAS TODAY... HIGH PRESSURE REMAINS CENTERED OFF THE MID ATLANTIC COAST THROUGH FRIDAY. A COLD FRONT APPROACHES FROM THE NORTH ON SATURDAY...THEN STALLS ACROSS NORTHERN VIRGINIA SATURDAY NIGHT AND SUNDAY. RELATIVE HUMIDITIES THIS AFTERNOON WILL DROP TO BETWEEN 25 AND 30 PERCENT OVER MUCH OF THE INTERIOR PORTIONS OF THE REGION. .TODAY... SKY/WEATHER.........SUNNY (0-5 PERCENT). MAX TEMPERATURE.....AROUND 85. MIN HUMIDITY........25 PERCENT. WIND (20FT/2MIN)....LIGHT WINDS...BECOMING SOUTH 5 TO 7 MPH IN THE AFTERNOON. MIXING HEIGHT.......300-1400 FT AGL...INCREASING TO 4700-5500 FT AGL. TRANSPORT WINDS.....SOUTH 2 TO 9 MPH. VENTILATION RATE....VERY POOR TO FAIR (600-45300 FT-MPH). TIME (EDT) 12P 1PM 2PM 3PM 4PM 5PM 6PM 7PM 8PM 9PM 10P 11P SKY (%).........0 2 2 2 0 0 0 0 0 1 1 2 WEATHER COV..... WEATHER TYPE.... TEMP............80 82 83 84 85 84 82 78 73 68 63 60 RH..............35 33 31 28 26 27 34 40 49 59 70 81 20 FT WIND DIR..S S S S S S S S S S S S 20 FT WIND SPD..4 4 5 5 6 6 5 3 3 3 3 3 20 FT WIND GUST.10 10 10 10 10 15 10 5 5 5 5 5 MIX HGT (KFT)...4.1 4.7 5.3 5.3 5.4 5.5 3.8 2.0 0.3 0.3 0.3 0.3 MIXNG WIND DIR..SW S S S S S S S S S S S MIXNG WIND SPD..9 9 9 9 9 9 10 13 14 14 13 12 .TONIGHT... SKY/WEATHER.........CLEAR (0-10 PERCENT). MIN TEMPERATURE.....AROUND 54. MAX HUMIDITY........96 PERCENT. WIND (20FT/2MIN)....SOUTH WINDS AROUND 6 MPH EARLY IN THE EVENING...BECOMING LIGHT. .FRIDAY... MIN HUMIDITY........37 PERCENT. WIND (20FT/2MIN)....LIGHT WINDS...BECOMING SOUTH 5 TO 7 MPH IN THE AFTERNOON. FORECASTER...RUSNAK REQUESTED BY...STONE TYPE OF REQUEST...PRESCRIBED .TAG 20090521.PETTI.01/AKQ