FNUS75 KBYZ 101620
FWSBYZ

SPOT FORECAST FOR GRASSY RX...USDA FOREST SERVICE GALLATIN NATIONAL FOREST
NATIONAL WEATHER SERVICE BILLINGS MT
1020 AM MDT FRI MAY 10 2013

FORECAST IS BASED ON IGNITION TIME OF 1005 MDT ON MAY 10.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.

.DISCUSSION...
A COLD FRONT WILL MOVE THROUGH THE BURN SITE LATE THIS MORNING.
THIS FRONT WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
THIS AFTERNOON AND EVENING. A DISTURBANCE WILL MOVE THROUGH THE
AREA SATURDAY AFTERNOON AND PROVIDE ANOTHER SHOT OF SHOWERS AND
THUNDERSTORMS. SUNDAY LOOKS MAINLY DRY AS HIGH PRESSURE TRIES TO
WORK INTO THE AREA. WARMER TEMPERATURES ARE EXPECTED SUNDAY AND
MONDAY WITH LOWERING HUMIDITIES EACH DAY. WINDS WILL BE DRIVEN
PRIMARILY BY TERRAIN TODAY THROUGH SUNDAY...BUT WILL GET ERRATIC
IN THE AFTERNOON AS UPSLOPE WINDS BATTLE WINDS ALOFT WHICH WILL BE
PRIMARILY OUT OF THE WEST. MONDAY WILL HAVE THE STRONGEST WINDS
AS WINDS ALOFT INCREASE FROM THE SOUTHWEST. A COLD FRONT WILL PUSH
INTO THE AREA MONDAY EVENING AND THIS WILL TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS. TWH


.TODAY...

SKY/WEATHER.........BECOMING PARTLY CLOUDY. SCATTERED SHOWERS AND
                    ISOLATED THUNDERSTORMS DEVELOPING IN THE
                    AFTERNOON.
CWR.................16 PERCENT.
LAL.................2...1 TO 8 STRIKES/15 MIN/CELL.
MAX TEMPERATURE.....58-63.
MIN HUMIDITY........34-39 PERCENT.
WIND (20 FT)........
 SLOPE/VALLEY.......NORTHWEST WINDS 5 TO 10 MPH. WINDS ERRATIC IN
                    THE AFTERNOON. GUSTY AND ERRATIC WINDS EXPECTED
                    NEAR THUNDERSTORMS.
 RIDGETOP...........NORTHWEST 5 TO 15 MPH.
MIXING HEIGHT.......6400 FT AGL.
MIXING WINDS........NORTHWEST 5 TO 15 MPH.
HAINES INDEX........5.

.TONIGHT...

SKY/WEATHER.........MOSTLY CLOUDY. SCATTERED SHOWERS AND ISOLATED
                    THUNDERSTORMS IN THE EVENING...THEN ISOLATED
                    SHOWERS OVERNIGHT.
CWR.................16 PERCENT.
LAL.................2...1 TO 8 STRIKES/15 MIN/CELL.
MIN TEMPERATURE.....36-41.
MAX HUMIDITY........85-90 PERCENT.
WIND (20 FT)........
 SLOPE/VALLEY.......NORTHEAST WINDS 5 TO 15 MPH IN THE EARLY EVENING.
                    WINDS BECOMING DOWNSLOPE BY LATE EVENING. GUSTY
                    AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS.
 RIDGETOP...........NORTHWEST 5 TO 15 MPH.
MIXING HEIGHT.......3800 FT AGL.
MIXING WINDS........NORTHWEST 5 TO 10 MPH.
HAINES INDEX........4.

.SATURDAY...

SKY/WEATHER.........PARTLY SUNNY. ISOLATED SHOWERS IN THE
                    MORNING...THEN SCATTERED SHOWERS AND
                    THUNDERSTORMS IN THE AFTERNOON.
CWR.................14 PERCENT.
LAL.................3...9 TO 15 STRIKES/15 MIN/CELL.
MAX TEMPERATURE.....61-66.
MIN HUMIDITY........30-35 PERCENT.
WIND (20 FT)........
 SLOPE/VALLEY.......DOWNSLOPE WINDS 5 TO 10 MPH IN THE MORNING
                    SHIFTING UPSLOPE BY LATE MORNING. WINDS ERRATIC
                    IN THE AFTERNOON. GUSTY AND ERRATIC WINDS
                    EXPECTED NEAR THUNDERSTORMS.
 RIDGETOP...........WEST 10 TO 20 MPH.
MIXING HEIGHT.......9400 FT AGL.
MIXING WINDS........WEST 5 TO 15 MPH.
HAINES INDEX........5.

.SUNDAY...

SKY/WEATHER.........PARTLY SUNNY. ISOLATED SHOWERS AND
                    THUNDERSTORMS IN THE AFTERNOON.
CWR.................14 PERCENT.
LAL.................2...1 TO 8 STRIKES/15 MIN/CELL.
MAX TEMPERATURE.....65-70.
MIN HUMIDITY........28-33 PERCENT.
WIND (20 FT)........
 SLOPE/VALLEY.......DOWNSLOPE WINDS 5 TO 10 MPH EARLY MORNING
                    BECOMING UPSLOPE 5 TO 15 MPH BY MID MORNING.
                    WINDS ERRATIC IN THE AFTERNOON WITH SOME GUSTS
                    TO 20 MPH POSSIBLE NEAR THE TOP OF THE SLOPES.
                    GUSTY AND ERRATIC WINDS EXPECTED NEAR
                    THUNDERSTORMS.
 RIDGETOP...........WEST 10 TO 20 MPH. STRONGEST IN THE MORNING.
MIXING HEIGHT.......9400 FT AGL.
MIXING WINDS........WEST 10 TO 20 MPH.
HAINES INDEX........5.

.MONDAY...

SKY/WEATHER.........PARTLY SUNNY. SCATTERED SHOWERS AND
                    THUNDERSTORMS.
CWR.................14 PERCENT.
LAL.................3...9 TO 15 STRIKES/15 MIN/CELL.
MAX TEMPERATURE.....68-73.
MIN HUMIDITY........25-30 PERCENT.
WIND (20 FT)........
 SLOPE/VALLEY.......SOUTH TO SOUTHWEST WINDS 10 TO 20 MPH WITH
                    GUSTS TO 25 MPH. GUSTY AND ERRATIC WINDS
                    EXPECTED NEAR THUNDERSTORMS.
 RIDGETOP...........SOUTHWEST 15 TO 30 MPH.
MIXING HEIGHT.......9400 FT AGL.
MIXING WINDS........SOUTHWEST 15 TO 25 MPH.
HAINES INDEX........5.

$$
FORECASTER...HUMPHREY
REQUESTED BY...CRISTI HEANEY
TYPE OF REQUEST...PRESCRIBED
.TAG 20130510.GRASS.01/BYZ