FNUS75 KRIW 251337
FWSRIW

SPOT FORECAST FOR LOWER GROS VENTRE...BRIDGER TETON NATIONAL FOREST
NATIONAL WEATHER SERVICE RIVERTON WY
737 AM MDT FRI SEP 25 2009

FORECAST IS BASED ON IGNITION TIME OF 0725 MDT ON SEPTEMBER 25.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.

.DISCUSSION...
FINAL DAY OF THE NORTH FLOW BEFORE THE UPPER LOW FINALLY MOVES OFF
EAST. EXPECT ANOTHER UNSTABLE...DRY AND SUNNY DAY TODAY. A WEAK
TROUGH WILL MOVE THROUGH OVERNIGHT TODAY BACKING THE FLOW TO THE
WEST TO NORTHWEST. NO WEATHER OR EVEN APPRECIABLE CLOUDS ARE
EXPECTED WITH THE TROUGH PASSAGE. SOUTH TO SOUTHWEST WINDS SURFACE
WINDS WILL BEGIN TO INCREASE SATURDAY IN RESPONSE TO A ANOTHER
TROUGH MOVING ACROSS CANADA. THE TROUGH MOVES THROUGH VEERING THE
WINDS TO THE NORTHWEST ON SUNDAY. THE TROUGH NEXT WEEK STILL LOOKS
ON TRACK WITH WINDS INCREASING MONDAY AND TUESDAY...WITH A TURN TO
COOLER AND WETTER CONDITIONS TUESDAY/WEDNESDAY INTO THURSDAY.

...THUNDERSTORMS IMPLY STRONG GUSTY AND ERRATIC WINDS...
...HAINES INDEX IS HIGH LEVEL HAINES BOTH DAY AND NIGHT...

FORECASTER...T.BAKER

.TODAY...
SKY/WEATHER.........MOSTLY SUNNY (15-25 PERCENT).
MAX TEMPERATURE.....68-72.
MIN HUMIDITY........16-18 PERCENT.
20 FOOT WINDS.......LIGHT AND VARIABLE...BECOMING NORTH TO NORTHEAST
                    5-10 MPH AROUND 1300.
RIDGE TOP WINDS.....VARIABLE 3-7 MPH...BECOMING NORTH 5-10 MPH
                    GUSTS TO 20 MPH AROUND 1300.
LAL.................1.
CHC OF WETTING RAIN.ZERO PERCENT.
HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME DOMINATED
                    FIRE GROWTH.
MIXING HEIGHT.......500 FT AGL INCREASING TO 8000 FT AGL AROUND NOON.
TRANSPORT WINDS.....NORTH 15 MPH.
SMOKE DISPERSAL.....POOR (7500 KNOT-FT) INCREASING TO (120000 KNOT-FT)
                    IN THE AFTERNOON.

.TONIGHT...
SKY/WEATHER.........MOSTLY CLEAR (15-25 PERCENT).
MIN TEMPERATURE.....40-43.
MAX HUMIDITY........46-49 PERCENT.
20 FOOT WINDS.......NORTHWEST TO NORTH WINDS 5-10 MPH EARLY IN THE
                    EVENING BECOMING DOWNSLOPE/DOWNVALLEY 2-6 MPH.
RIDGE TOP WINDS.....NORTH TO NORTHWEST 10 TO 15 MPH...BECOMING
                    WEST-NORTHWEST 5-10 MPH.
LAL.................1.
CHC OF WETTING RAIN.ZERO PERCENT.
HAINES INDEX........4 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED
                    FIRE GROWTH.
MIXING HEIGHT.......5000 FT AGL DECREASING TO 500 FT AGL AFTER
                    MIDNIGHT.
TRANSPORT WINDS.....NORTH TO NORTHWEST 15 MPH SHIFTING TO THE NORTHWEST
                    EARLY IN THE MORNING.
SMOKE DISPERSAL.....FAIR (45000 KNOT-FT) DECREASING TO POOR (7500
                    KNOT-FT) AFTER MIDNIGHT.

.SATURDAY...
SKY/WEATHER.........SUNNY (5-15 PERCENT).
MAX TEMPERATURE.....65-70.
MIN HUMIDITY........16-20 PERCENT.
20 FOOT WINDS.......LIGHT AND VARIABLE IN THE MORNING...BECOMING SOUTH TO
                    SOUTHWEST 5-10 MPH WITH SOME HIGHER GUSTS AROUND
                    1300.
RIDGE TOP WINDS.....VARIABLE 4-8 MPH...BECOMING SOUTHWEST 10-15 MPH WITH
                    GUSTS TO AROUND 25 MPH AROUND 1300.
LAL.................1.
CHC OF WETTING RAIN.ZERO PERCENT.
HAINES INDEX........5 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED
                    FIRE GROWTH.
MIXING HEIGHT.......500 FT AGL INCREASING TO 8000 FT AGL IN THE
                    AFTERNOON.
TRANSPORT WINDS.....WEST 20 MPH.
SMOKE DISPERSAL.....POOR (10000 KNOT-FT) INCREASING TO EXCELLENT (160000
                    KNOT-FT) IN THE AFTERNOON.

.FORECAST DAYS 3 THROUGH 5...
.SATURDAY NIGHT...CLEAR. LOWS AROUND 40. WEST WINDS AROUND
10-15 MPH.
.SUNDAY...MOSTLY CLEAR. LOWS IN THE LOWER 30S. HIGHS IN THE LOWER
60S. SOUTHWEST WINDS 10-15 MPH.
.MONDAY...MOSTLY CLEAR. LOWS IN THE LOWER 40S. HIGHS AROUND 60.
SOUTHWEST WINDS 15-20 MPH.
.TUESDAY...COOLER. PARTLY CLOUDY. CHANCE OF SHOWERS...
THUNDERSTORMS AND SNOW SHOWERS. LOWS AROUND 30. HIGHS IN THE
UPPER 40S. SOUTHWEST WINDS AROUND 15-20 MPH.

$$

FORECASTER...T.BAKER
REQUESTED BY...MACK
REASON FOR REQUEST...PRESCRIBED
.TAG 20090925.LOWER.01/RIW