FNUS75 KRIW 040738 FWSRIW SPOT FORECAST FOR LAVA RX...USFS BTF NATIONAL WEATHER SERVICE RIVERTON WY 138 AM MDT WED APR 4 2012 FORECAST IS BASED ON IGNITION TIME OF 1200 MDT ON APRIL 04. IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER SERVICE. .DISCUSSION...AN UPPER TROUGH OF LOW PRESSURE ALONG THE NORTHWEST COAST WILL EJECT A SERIES OF DISTURBANCES NORTHEAST ACROSS THE INTERMOUNTAIN WEST TODAY THROUGH FRIDAY. THE FIRST IN THIS SERIES WILL PUSH A COLD FRONT ACROSS EASTERN IDAHO THIS AFTERNOON...AND INTO NORTHWEST WYOMING LATE AFTERNOON/EARLY EVENING. SOUTHERLY WINDS WILL INCREASE THIS AFTERNOON AS A SURFACE LOW DEEPENS OVER WESTERN MONTANA FOLLOWED BY A WIND SHIFT FROM THE WEST WITH THE FRONT. THE BULK OF SNOW SHOWERS WILL STAY WEST OF THE BURN AREA WITH THE BEST WINDOW FOR SOME PASSING SNOW SHOWERS 1600L TO AROUND MIDNIGHT. SOME DRYING WILL OCCUR THURSDAY MORNING...WITH GUSTY WINDS AND SHOWER ACTIVITY PICKING UP AGAIN THURSDAY AFTERNOON. TEMPERATURES WILL SHOW LITTLE TREND TODAY WITH SLIGHTLY HIGHER RELATIVE HUMIDITY...FOLLOWED BY COOLER TEMPERATURES AND HIGHER RELATIVE HUMIDITY ON THURSDAY. ...THUNDERSTORMS IMPLY STRONG GUSTY AND ERRATIC WINDS... ...HAINES INDEX IS HIGH LEVEL HAINES BOTH DAY AND NIGHT... FORECASTER...MEUNIER .TODAY... SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT)...BECOMING MOSTLY CLOUDY (60-70 PERCENT) AFTER 1600L WITH ISOLATED SNOW SHOWERS. MAX TEMPERATURE.....54-57. MIN HUMIDITY........32-35 PERCENT. 20 FOOT WINDS.......DOWN VALLEY OR EAST 4-7 MPH UNTIL 1000L...THEN BECOMING SOUTH SOUTHWEST AND INCREASING TO 11 TO 16 MPH WITH GUSTS TO 25 MPH BETWEEN 1300L AND 1500L. RIDGE TOP WINDS.....SOUTH 5 TO 10 MPH...BECOMING SOUTH SOUTHWEST 15 TO 20 MPH BETWEEN 1300L AND 1500L. HAINES INDEX........2 OR VERY LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......2100-3100 FT AGL LATE MORNING...INCREASING TO 6000- 7000 FT AGL BETWEEN 1300L AND 1500L. TRANSPORT WINDS.....SOUTH AROUND 15 MPH LATE MORNING...BECOMING SOUTHWEST AND INCREASING TO 20 TO 25 MPH IN THE AFTERNOON. SMOKE DISPERSAL.....POOR TO FAIR IN THE MORNING (35000-45000 KNOT-FT)... BECOMING VERY GOOD BETWEEN 1300L AND 1500L. .TONIGHT... SKY/WEATHER.........MOSTLY CLOUDY (70-80 PERCENT). SLIGHT CHANCE OF RAIN AND SNOW SHOWERS. MIN TEMPERATURE.....25-28. MAX HUMIDITY........81-84 PERCENT. 20 FOOT WINDS.......WEST WINDS AROUND 8 MPH WITH GUSTS TO AROUND 15 MPH EARLY IN THE EVENING SHIFTING FROM THE NORTH SHORTLY AFTER SUNSET...BECOMING DOWNSLOPE/DOWNVALLEY 4-7 MPH AFTER MIDNIGHT. RIDGE TOP WINDS.....SOUTH 10 TO 15 MPH. HAINES INDEX........2 OR VERY LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......3100-4100 FT AGL EARLY EVENING...DECREASING TO 500-1000 FT AGL AFTER MIDNIGHT. TRANSPORT WINDS.....SOUTH 10 TO 15 MPH. SMOKE DISPERSAL.....GOOD EARLY EVENING...THEN BECOMING POOR BY MIDNIGHT. .THURSDAY... SKY/WEATHER.........CLOUDY (75-85 PERCENT). CHANCE OF SNOW SHOWERS...MAINLY IN THE AFTERNOON. MAX TEMPERATURE.....40-43. MIN HUMIDITY........46-49 PERCENT. 20 FOOT WINDS.......WEST SOUTHWEST 4-7 MPH IN THE MORNING...BECOMING SOUTHWEST AROUND 10 MPH IN THE AFTERNOON. RIDGE TOP WINDS.....SOUTH 5 TO 10 MPH INCREASING TO 15 TO 20 MPH IN THE AFTERNOON. HAINES INDEX........3 OR VERY LOW POTENTIAL FOR LARGE PLUME DOMINATED FIRE GROWTH. MIXING HEIGHT.......4300-5300 FT AGL. TRANSPORT WINDS.....SOUTH 10 TO 15 MPH INCREASING TO NEAR 20 MPH IN THE AFTERNOON. SMOKE DISPERSAL.....FAIR TO GOOD (58500-87900 KNOT-FT). .FORECAST DAYS 3 THROUGH 5... .THURSDAY NIGHT...CLOUDY WITH CHANCE OF SNOW SHOWERS. LOWS IN THE LOWER 20S. WINDS GENERALLY LESS THAN 10 MPH. .FRIDAY...MOSTLY CLOUDY WITH CHANCE OF SNOW SHOWERS. LOWS AROUND 15. HIGHS IN THE LOWER 30S. WINDS GENERALLY LESS THAN 10 MPH. .SATURDAY...PARTLY CLOUDY. LOWS AROUND 19. HIGHS IN THE UPPER 30S. WINDS GENERALLY LESS THAN 10 MPH. .SUNDAY...NOT AS COOL. PARTLY CLOUDY. LOWS IN THE MID 20S. HIGHS IN THE UPPER 40S. WINDS GENERALLY LESS THAN 10 MPH. $$ FORECASTER...MEUNIER REQUESTED BY...JASON LAWHON REASON FOR REQUEST...PRESCRIBED .TAG 20120404.LAVAR.01/RIW