FNUS75 KMSO 232247
FWSMSO

SPOT FORECAST FOR WEST RIVER FIRE
NATIONAL WEATHER SERVICE MISSOULA MT
447 PM MDT TUE AUG 23 2011

FORECAST IS BASED ON REQUEST TIME OF 1613 MDT ON AUGUST 23.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.

.DISCUSSION...WINDS BEHIND AN EXITING WEATHER SYSTEM WILL REMAIN
OVER THE FIRE THE REST OF THE AFTERNOON INTO THE EARLY EVENING.
ANOTHER SURGE OF DRAINAGE WINDS WILL DEVELOP RIGHT AFTER SUNSET
AND LAST FOR ABOUT ONE HOUR. A THERMAL BELT WILL DEVELOP AT MID
SLOPE TONIGHT WITH CLEAR SKIES AND DECREASING PRESSURE
GRADIENT...BUT THE TOP AND BOTTOM OF THE FIRE WILL BE DOWNSLOPE
2-4 MPH. HIGH POTENTIAL FOR SMOKE TO GET TRAPPED IN EASTERN
MISSOULA VALLEY AND POINTS EAST TONIGHT INTO WEDNESDAY. A RIDGE
WILL RE- AMPLIFY OVER THE FIRE WEDNESDAY INCREASING TEMPERATURES
AND INSTABILITY. DIURNAL/TERRAIN WINDS WILL BE DOMINANT MOST OF
THE DAY...BUT LATE DAY MIXING WILL ALLOW WEST WINDS 5-10 MPH TO
MIX TO THE SURFACE. THE TOP OF THE FIRE COULD SEE GUSTS OUT OF THE
WEST TO 25 MPH.

NOTE: THERE IS ALSO A POTENTIAL FOR SOME NOCTURNAL THUNDERSTORMS
IMPACTING THE FIRE AFTER MIDNIGHT WEDNESDAY INTO EARLY THURSDAY
MORNING. GIVEN VERY DRY LOW LEVELS...LIGHTNING AND WINDS WILL BE
THE MAIN IMPACTS.

.REST OF TODAY...

SKY/WEATHER.........MOSTLY SUNNY.
CWR.................0 PERCENT.
MAX TEMPERATURE.....85-90 BOTTOM...73-78 TOP.
MIN HUMIDITY........14-19 PERCENT BOTTOM....33-38 PERCENT TOP.
WIND (20 FT)........WEST 12-18 MPH WITH GUST TO 25 MPH.
MIXING HEIGHT.......6300 FT AGL.
MIXING WINDS........WEST 25 MPH.
HAINES INDEX........2 VERY LOW.

.TONIGHT...

SKY/WEATHER.........MOSTLY CLEAR.
CWR.................0 PERCENT.
MIN TEMPERATURE.....47-52 BOTTOM...57-62 MID SLOPE/TOP.
MAX HUMIDITY........56-61 PERCENT BOTTOM....40-45 PERCENT
                    MID SLOPE/TOP
WIND (20 FT)........WEST WINDS 10-15 MPH IN THE EARLY EVENING
                    BECOMING DOWNSLOPE 2-5 MPH AFTER 2130 MDT.
                    MID SLOPE WINDS WEST 5-9 MPH
MIXING HEIGHT.......300 FT AGL.
MIXING WINDS........SOUTHWEST 10 MPH.
HAINES INDEX........2 VERY LOW.

.WEDNESDAY...

SKY/WEATHER.........MOSTLY SUNNY.
CWR.................0 PERCENT.
MAX TEMPERATURE.....90-95 BOTTOM...78-83 TOP.
MIN HUMIDITY........4-9 PERCENT BOTTOM...19-24 PERCENT TOP.
WIND (20 FT)........UPSLOPE 2-4 MPH BECOMING WEST 9-12 MPH IN
                    THE AFTERNOON...MAINLY AFTER 1700 AT THE BOTTOM.
                    MIDSLOPES AND TOP OF FIRE SEEING WINDS AFTER
                    1400 MDT. GUSTS TO 25 MPH AT THE TOP OF FIRE.
MIXING HEIGHT.......8900 FT AGL.
MIXING WINDS........WEST 15 MPH.
HAINES INDEX........3 VERY LOW.

$$
FORECASTER...MEAD
REQUESTED BY...MATT BUTLER
TYPE OF REQUEST...WILDFIRE
.TAG 20110823.WESTR.01/MSO