FNUS75 KRIW 231346 FWSRIW SPOT FORECAST FOR TETON VALLEY RANCH NORTH...NPS GTP NATIONAL WEATHER SERVICE RIVERTON WY 746 AM MDT MON APR 23 2012 FORECAST IS BASED ON IGNITION TIME OF 1100 MDT ON APRIL 23. IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER SERVICE. .DISCUSSION...A LARGE HIGH PRESSURE RIDGE ALOFT EXTENDS OVER THE WESTERN U.S. WITH THE RIDGE AXIS OVER EASTERN IDAHO. THE RIDGE AXIS WILL MOVE EAST OF THE BURN AREA THROUGH THE AFTERNOON. A SERIES OF WEAK LOW PRESSURE SHORT WAVE TROUGHS MOVING THROUGH THE RIDGE WILL IMPACT THE BURN AREA THROUGH WEDNESDAY. THE FIRST SHORT WAVE TROUGH OVER NORTHERN NEVADA HAS EXTENSIVE CLOUD COVER AND EMBEDDED SHOWERS EXTENDS ACROSS NORTHERN UTAH AND SOUTHERN IDAHO INTO WESTERN WYOMING. THE FIRST WAVE OF CLOUDS OVER WESTERN WYOMING WILL MOVE EAST THROUGH THIS MORNING WITH PARTIAL CLEARING. DAYTIME HEATING AND AVAILABLE MID AND LOW LEVEL MOISTURE WILL SUPPORT INCREASED CONVECTION BY 1 PM MDT WITH INCREASED SHOWERS OVER THE MOUNTAINS AND ISOLATED THUNDERSTORMS WHICH MAY PRODUCE STRONG OUTFLOW WINDS OVER THE BURN AREA. SHOWERS AND THUNDERSTORMS WILL BE A THREAT INTO THE EVENING DECREASING BY 8 PM MDT BUT SOME LINGERING SHOWERS SHOULD BE OVER THE AREA THROUGH THE NIGHT. AS THE FLOW ALOFT BECOME SOUTHWEST ON THE WEST SIDE OF THE RIDGE AXIS... MOISTURE ALOFT WILL INCREASE TUESDAY AND WEDNESDAY WITH INCREASED SHOWER AND THUNDERSTORMS BOTH DAYS. THIS WILL ALSO BRING INCREASED SOUTHWEST WINDS IN THE AFTERNOONS. TEMPERATURES WILL BE THE WARMEST TODAY THEN COOL TUESDAY AND WEDNESDAY WITH INCREASED CLOUD COVER AND PRECIPITATION. THIS WILL ALSO BRING UP SURFACE RELATIVE HUMIDITY THROUGH MID WEEK, ...THUNDERSTORMS IMPLY STRONG GUSTY AND ERRATIC WINDS... ...HAINES INDEX IS HIGH LEVEL HAINES BOTH DAY AND NIGHT... FORECASTER...C.BAKER .TODAY... SKY/WEATHER.........PARTLY CLOUDY (30-40 PERCENT) THEN BECOMING MOSTLY CLOUDY (70-80 PERCENT) BY 1 PM MDT . SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS WITH SMALL HAIL AND GUSTY WINDS IN THE AFTERNOON. MAX TEMPERATURE.....74-76. MIN HUMIDITY........18-23 PERCENT. 20 FOOT WINDS.......UPSLOPE/UPVALLEY 5-9 MPH. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS IN THE AFTERNOON. RIDGE TOP WINDS.....SOUTH 5 TO 10 MPH SHIFTING TO THE SOUTHWEST AROUND 15 MPH LATE IN THE AFTERNOON. LAL.................1 UNTIL 1200...THEN 2. CHC OF WETTING RAIN.10 PERCENT. HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......3700-4700 FT AGL INCREASING TO 8700-9700 FT AGL IN THE AFTERNOON. TRANSPORT WINDS.....SOUTHEAST 9 TO 12 MPH SHIFTING TO THE SOUTHWEST 13 TO 16 MPH IN THE AFTERNOON. SMOKE DISPERSAL.....POOR (37900 KNOT-FT) INCREASING TO VERY GOOD (109800 KNOT-FT) BY 11 AM MDT. .TONIGHT... SKY/WEATHER.........MOSTLY CLOUDY (60-70 PERCENT). SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS IN THE EVENING WITH SMALL HAIL AND STRONG GUSTY WINDS... THEN OCCASIONAL SPRINKLES AFTER MIDNIGHT. MIN TEMPERATURE.....AROUND 37. MAX HUMIDITY........82-85 PERCENT. 20 FOOT WINDS.......SOUTHWEST WINDS AROUND 8 MPH WITH GUSTS TO AROUND 15 MPH EARLY IN THE EVENING BECOMING DOWNSLOPE/DOWNVALLEY 4-7 MPH. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS IN THE EVENING. RIDGE TOP WINDS.....SOUTHWEST AROUND 15 MPH BECOMING SOUTH AROUND 5 MPH LATE IN THE EVENING...THEN SHIFTING TO THE SOUTHEAST AFTER MIDNIGHT. LAL.................2 UNTIL 2400...THEN 1. CHC OF WETTING RAIN.10 PERCENT. HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......5900-6900 FT AGL DECREASING TO 1400-1900 FT AGL AFTER MIDNIGHT. TRANSPORT WINDS.....SOUTHWEST 14 TO 16 MPH SHIFTING TO THE SOUTHEAST 12 TO 13 MPH AFTER MIDNIGHT. SMOKE DISPERSAL.....GOOD (84300 KNOT-FT) DECREASING TO POOR (16800 KNOT-FT) AFTER 9 PM MDT. .TUESDAY... SKY/WEATHER.........MOSTLY CLOUDY (75-85 PERCENT). OCCASIONAL SPRINKLES IN THE MORNING...THEN SCATTERED RAIN SHOWERS AND ISOLATED DRY THUNDERSTORMS IN THE AFTERNOON. MAX TEMPERATURE.....AROUND 70. MIN HUMIDITY........19-23 PERCENT. 20 FOOT WINDS.......UPSLOPE/UPVALLEY 5-9 MPH BECOMING SOUTHWEST AROUND 12 MPH WITH GUSTS TO AROUND 25 MPH LATE IN THE AFTERNOON. GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS IN THE AFTERNOON. RIDGE TOP WINDS.....SOUTH 10 TO 15 MPH SHIFTING TO THE SOUTHWEST AROUND 20 MPH LATE IN THE AFTERNOON. LAL.................1 UNTIL 1200...THEN 2. CHC OF WETTING RAIN.15 PERCENT. HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......5300-6300 FT AGL INCREASING TO 9800 FT AGL IN THE AFTERNOON. TRANSPORT WINDS.....SOUTH AROUND 13 MPH INCREASING TO WEST 22 TO 24 MPH IN THE AFTERNOON. SMOKE DISPERSAL.....GOOD (75800 KNOT-FT) INCREASING TO EXCELLENT (163100 KNOT-FT) IN THE AFTERNOON. .FORECAST DAYS 3 THROUGH 5... .TUESDAY NIGHT...MOSTLY CLOUDY. SCATTERED SHOWERS AND THUNDERSTORMS IN THE EVENING...THEN ISOLATED SHOWERS AFTER MIDNIGHT. LOWS IN THE MID 30S. WINDS GENERALLY LESS THAN 10 MPH. .WEDNESDAY...MOSTLY CLOUDY WITH SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS. LOWS IN THE MID 30S. HIGHS IN THE UPPER 60S. WINDS SOUTH SOUTHWEST AT 15 MPH AND GUSTY IN THE AFTERNOON. .THURSDAY...MOSTLY CLOUDY WITH CHANCE OF SHOWERS...RAIN SHOWERS AND ISOLATED THUNDERSTORMS. LOWS IN THE LOWER 30S. HIGHS IN THE LOWER 60S. WINDS GENERALLY LESS THAN 10 MPH. .FRIDAY...COOLER. MOSTLY CLOUDY WITH CHANCE OF RAIN AND SHOWERS AND SNOW SHOWERS. LOWS IN THE UPPER 20S. HIGHS IN THE MID 40S. WINDS GENERALLY LESS THAN 10 MPH. $$ FORECASTER...C.BAKER REQUESTED BY...ANDY HALL REASON FOR REQUEST...PRESCRIBED .TAG 20120423.TETON.01/RIW