FNUS75 KRIW 222142 FWSRIW SPOT FORECAST FOR ANTELOPE...NPS YNP NATIONAL WEATHER SERVICE RIVERTON WY 342 PM MDT WED SEP 22 2010 FORECAST IS BASED ON REQUEST TIME OF 1532 MDT ON SEPTEMBER 22. IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER SERVICE. .DISCUSSION... MOISTURE AND INSTABILITY WILL INCREASE OVER THE AREA THROUGH THIS EVENING IN SOUTHWEST FLOW ALOFT AHEAD OF A PACIFIC LOW PRESSURE TROUGH OVER WESTERN IDAHO AND NEVADA. THIS WILL BRING INCREASED CLOUDS...SHOWERS AND SOME THUNDERSTORMS WITH COOLER TEMPERATURES AND HIGHER HUMIDITY DUE TO CLOUD COVER AND EVAPORATIVE COOLING FROM PRECIPITATION. THE TROUGH WILL PASS THROUGH LATE TONIGHT AND EARLY THURSDAY MORNING WITH COLDER AND STABLE AIR MOVING IN...IN NORTHWEST FLOW ALOFT. THIS WILL BRING MORE FAVORABLE HUMIDITY LOWER MIXING HEIGHTS AND COOLER TEMPERATURES. CLEARING WILL OCCUR BY LATE THURSDAY MORNING WITH SOME SHOWERS LINGERING OVER THE CONTINENTAL DIVIDE INTO THE AFTERNOON. ...THUNDERSTORMS IMPLY STRONG GUSTY AND ERRATIC WINDS... ...HAINES INDEX IS HIGH LEVEL HAINES BOTH DAY AND NIGHT... FORECASTER...C.BAKER .REST OF TODAY... SKY/WEATHER.........MOSTLY CLOUDY (60-70 PERCENT). SCATTERED SHOWERS AND THUNDERSTORMS. MAX TEMPERATURE.....55-60. MIN HUMIDITY........25-30 PERCENT. 20 FOOT WINDS.......SOUTHWEST WINDS AROUND 10 MPH AND GUSTY. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS. RIDGE TOP WINDS.....SOUTHWEST AROUND 15 MPH. LAL.................2. CHC OF WETTING RAIN.20 PERCENT. HAINES INDEX........4 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......8900 FT AGL. TRANSPORT WINDS.....SOUTHWEST AROUND 18 MPH. SMOKE DISPERSAL.....GOOD (87200 KNOT-FT). .TONIGHT... SKY/WEATHER.........MOSTLY CLOUDY (65-75 PERCENT). SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS IN THE EVENING...THEN ISOLATED RAIN SHOWERS AND SNOW SHOWERS AFTER MIDNIGHT. MIN TEMPERATURE.....32-35. MAX HUMIDITY........93-96 PERCENT. 20 FOOT WINDS.......DOWNSLOPE/DOWNVALLEY 4-7 MPH. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS IN THE EVENING. RIDGE TOP WINDS.....NORTHWEST AROUND 10 MPH SHIFTING TO THE NORTH AFTER MIDNIGHT...THEN SHIFTING TO THE NORTHWEST EARLY IN THE MORNING. LAL.................2 UNTIL 2400...THEN 1. CHC OF WETTING RAIN.20 PERCENT. HAINES INDEX........4 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......5500-6500 FT AGL DECREASING TO 1600-2600 FT AGL AFTER MIDNIGHT. TRANSPORT WINDS.....NORTHWEST 9 TO 14 MPH. SMOKE DISPERSAL.....BECOMING POOR BY 10 PM MDT (16000-20000 KNOT-FT). .THURSDAY... SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT). ISOLATED RAIN SHOWERS IN THE MORNING. MAX TEMPERATURE.....55-60. MIN HUMIDITY........27-32 PERCENT. 20 FOOT WINDS.......UPSLOPE/UPVALLEY 5-9 MPH. GUSTS UP TO 15 MPH IN THE AFTERNOON. RIDGE TOP WINDS.....WEST 5 TO 10 MPH INCREASING TO AROUND 15 MPH LATE IN THE AFTERNOON. LAL.................1. CHC OF WETTING RAIN.LESS THAN 5 PERCENT. HAINES INDEX........3 OR VERY LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......2200-3200 FT AGL INCREASING TO 5400-6400 FT AGL IN THE AFTERNOON. TRANSPORT WINDS.....WEST 8 TO 17 MPH. SMOKE DISPERSAL.....POOR (25100 KNOT-FT) INCREASING TO GOOD (77900 KNOT-FT) BY NOON. .FORECAST DAYS 3 THROUGH 5... .THURSDAY NIGHT...PARTLY CLOUDY. LOWS IN THE LOWER 30S. WINDS GENERALLY LESS THAN 10 MPH. .FRIDAY...MOSTLY CLEAR. LOWS IN THE LOWER 30S. HIGHS IN THE UPPER 60S. WINDS GENERALLY LESS THAN 10 MPH. .SATURDAY...CLEAR. LOWS IN THE MID 30S. HIGHS IN THE MID 70S. WINDS GENERALLY LESS THAN 10 MPH. .SUNDAY...CLEAR. LOWS IN THE MID 30S. HIGHS IN THE MID 70S. WINDS GENERALLY LESS THAN 10 MPH. $$ FORECASTER...C.BAKER REQUESTED BY...LAURA DOOLEY REASON FOR REQUEST...WILDFIRE .TAG 20100922.ANTEL.01/RIW