FNUS75 KRIW 192151 FWSRIW SPOT FORECAST FOR EAST...NPS YNP NATIONAL WEATHER SERVICE RIVERTON WY 351 PM MDT THU AUG 19 2010 FORECAST IS BASED ON REQUEST TIME OF 1511 MDT ON AUGUST 19. IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER SERVICE. .DISCUSSION... AN UPPER LEVEL WEATHER DISTURBANCE WILL CONTINUE TO TRACK EAST ACROSS THE ROCKIES DURING THE REMAINDER OF THIS AFTERNOON. AS IT DOES IT WILL BISECT A MONSOON FEED. IN ADDITION...NOW THAT THE HIGHER CLOUDS HAVE EXITED THE AREA...THE INCREASED SOLAR INSULATION WILL ALLOW THE ATMOSPHERE TO DESTABILIZE. THIS WILL RESULT IN WIDELY SCATTERED THUNDERSTORM ACTIVITY DEVELOPING ACROSS THE VICINITY OF THE FIRE BY 1700. ANY THUNDERSTORMS AROUND THE AREA SHOULD QUICKLY DISSIPATE AROUND SUNRISE. ANY STORMS THAT FORM MAY PRODUCE BRIEF LOCALLY HEAVY RAINFALL. GUSTY ERRATIC 25 TO 35 MPH WINDS ARE POSSIBLE IN THE VICINITY OF ANY STORMS. WITH THIS TROUGH EXITING TO THE EAST AND HIGH PRESSURE BUILDING INTO THE AREA ...DRY WEATHER IS EXPECTED AFTER MIDNIGHT TONIGHT THROUGH FRIDAY. SOME CUMULUS BUILD UPS ARE EXPECTED FRIDAY AFTERNOON. SATURDAY AND SUNDAY WILL FEATURE HOTTER...DRIER AND WINDIER CONDITIONS CREATING INCREASINGLY CRITICAL FIRE WEATHER CONDITIONS AS THE SOUTHWEST FLOW INCREASES BETWEEN THE BUILDING RIDGE OVER THE PLAINS AND THE DEEPENING TROUGH ALONG THE WEST COAST. RIGHT NOW IT APPEARS THAT SUNDAY WILL BE THE MORE CRITICAL OF THE TWO DAYS. ...THUNDERSTORMS IMPLY STRONG GUSTY AND ERRATIC WINDS... ...HAINES INDEX IS HIGH LEVEL HAINES BOTH DAY AND NIGHT... FORECASTER...LIPSON .TONIGHT... SKY/WEATHER.........MOSTLY CLEAR (15-25 PERCENT). MIN TEMPERATURE.....36-39. MAX HUMIDITY........70-73 PERCENT. WIND (20 FT)........WEST SOUTHWEST WINDS 13 TO 15 MPH WITH GUSTS TO AROUND 25 MPH. EXPECT SOME EDDYING OF THE WINDS CREATING OCCASIONAL FLUCTUATING OF THE WIND DIRECTION AT THE LOWER ELEVATIONS. RIDGE TOP WINDS.....SOUTHWEST AROUND 20 MPH. LAL.................1. CWR.................ZERO PERCENT. HAINES INDEX........4 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......6500-7500 FT AGL DECREASING TO 2800-3800 FT AGL AFTER MIDNIGHT. TRANSPORT WINDS.....SOUTHWEST 21 TO 23 MPH. SMOKE DISPERSAL.....EXCELLENT (159200 KNOT-FT) DECREASING TO FAIR (59800 KNOT-FT) AFTER MIDNIGHT. .FRIDAY... SKY/WEATHER.........SUNNY (0-10 PERCENT) THEN BECOMING PARTLY CLOUDY (25-35 PERCENT). MAX TEMPERATURE.....69 AT 8270 FEET AND 73 AT 7130 FEET. MIN HUMIDITY........20 PERCENT AT 8270 FEET AND 18 PERCENT AT 7130 FEET. WIND (20 FT)........WEST SOUTHWEST WINDS 5 TO 10 MPH INCREASING TO 14 TO 17 MPH BY 1100 WITH GUSTS TO AROUND 25 MPH. EXPECT SOME EDDYING OF THE WINDS CREATING OCCASIONAL FLUCTUATING OF THE WIND DIRECTION IN THE AFTERNOON AT THE LOWER ELEVATIONS. RIDGE TOP WINDS.....WEST 20 TO 25 MPH. LAL.................1. CWR.................ZERO PERCENT. HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......3600-4600 FT AGL INCREASING TO 7000-8000 FT AGL IN THE AFTERNOON. TRANSPORT WINDS.....WEST 22 TO 25 MPH. SMOKE DISPERSAL.....GOOD (78000 KNOT-FT) INCREASING TO VERY GOOD (148300 KNOT-FT) IN THE AFTERNOON. .FORECAST DAYS 3 THROUGH 5... .FRIDAY NIGHT...MOSTLY CLEAR. LOWS AROUND 40. SOUTHWEST WINDS AROUND 12 MPH. .SATURDAY...PARTLY CLOUDY. ISOLATED SHOWERS AND THUNDERSTORMS. LOWS AROUND 40. HIGHS IN THE UPPER 70S. SOUTHWEST WINDS AROUND 13 MPH. .SUNDAY...PARTLY CLOUDY WITH CHANCE OF SHOWERS AND THUNDERSTORMS. LOWS IN THE MID 30S. HIGHS IN THE LOWER 70S. SOUTHWEST WINDS AROUND 10 MPH. .MONDAY...MOSTLY CLEAR WITH SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS. LOWS IN THE UPPER 20S. HIGHS AROUND 70. WINDS GENERALLY LESS THAN 10 MPH. .TUESDAY...MOSTLY CLEAR. LOWS IN THE MID 30S. HIGHS IN THE MID 70S. WINDS GENERALLY LESS THAN 10 MPH. $$ FORECASTER...LIPSON REQUESTED BY...EDWIN FOLTS REASON FOR REQUEST...WILDFIRE .TAG 20100819.EAST_.01/RIW