FNUS75 KRIW 212141
FWSRIW

SPOT FORECAST FOR ARTHUR 2...NPS YNP
NATIONAL WEATHER SERVICE RIVERTON WY
341 PM MDT SAT AUG 21 2010

FORECAST IS BASED ON REQUEST TIME OF 1514 MDT ON AUGUST 21.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.

.DISCUSSION...

SOUTHWEST FLOW WILL CONTINUE OVER THE ARTHUR FIRE THROUGH EARLY
SUNDAY EVENING. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
THIS EVENING. SOME SOUTHWEST BREEZES ARE EXPECTED TODAY AND
SUNDAY. THE THUNDERSTORM ACTIVITY WILL BECOME SCATTERED SUNDAY
AFTERNOON AND EVENING AS A PACIFIC TROUGH APPROACHES. GUSTY WINDS
TO 40 MPH AND LIGHTNING WILL BE THE MAIN THREATS. SOUTHWEST WINDS
WILL INCREASE AS WELL. THE WIND WILL SHIFT TO THE WEST TO
NORTHWEST AS THE TROUGH PASSES...PUSHING A COLD FRONT THROUGH.
MONDAY AND TUESDAY LOOK DRY...WITH DIMINISHING WINDS.

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

FORECASTER...T.BAKER

.TONIGHT...
SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT). ISOLATED
                    THUNDERSTORMS IN THE EVENING. ISOLATED RAIN
                    SHOWERS THROUGH THE NIGHT.
MIN TEMPERATURE.....41-44.
MAX HUMIDITY........76-79 PERCENT.
20 FOOT WINDS.......SOUTHWEST WINDS 6 TO 12 MPH. GUSTS UP TO 20
                    MPH.  DECREASING TO 5 TO 10 MPH AFTER 2100.
                    GUSTY AND ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS
                    IN THE EVENING.
RIDGE TOP WINDS.....SOUTHWEST 15 TO 20 MPH GUSTS TO 35 MPH.
LAL.................2 UNTIL 2400...THEN 1.
CHC OF WETTING RAIN.3 PERCENT.
HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME
                    DOMINATED FIRE GROWTH.
MIXING HEIGHT.......6100-7100 FT AGL DECREASING TO 2200-3200 FT AGL
                    AFTER MIDNIGHT.
TRANSPORT WINDS.....SOUTHWEST 22 TO 28 MPH.
SMOKE DISPERSAL.....EXCELLENT (151400 KNOT-FT) DECREASING TO FAIR
                    (57000 KNOT-FT) AFTER MIDNIGHT.

.SUNDAY...
SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT) THEN BECOMING
                    MOSTLY CLOUDY (65-75 PERCENT). ISOLATED RAIN
                    SHOWERS IN THE MORNING...THEN SCATTERED SHOWERS
                    AND THUNDERSTORMS IN THE AFTERNOON.
MAX TEMPERATURE.....72-75.
MIN HUMIDITY........23-27 PERCENT.
20 FOOT WINDS.......SOUTHWEST WINDS 8 TO 15 MPH WITH GUSTS TO
                    AROUND 30 MPH. GUSTY AND ERRATIC WINDS EXPECTED
                    NEAR THUNDERSTORMS IN THE AFTERNOON.
RIDGE TOP WINDS.....SOUTHWEST AROUND 15-25 MPH WITH GUSTS TO 35 MPH.
LAL.................1 UNTIL 1200...THEN 4.
CHC OF WETTING RAIN.15 PERCENT.
HAINES INDEX........4 OR LOW POTENTIAL FOR LARGE PLUME DOMINATED
                    FIRE GROWTH.
MIXING HEIGHT.......3700-4700 FT AGL INCREASING TO 6400-7400 FT AGL
                    IN THE AFTERNOON.
TRANSPORT WINDS.....SOUTHWEST 26 TO 28 MPH.
SMOKE DISPERSAL.....GOOD (97700 KNOT-FT) INCREASING TO EXCELLENT
                    (156100 KNOT-FT) IN THE AFTERNOON.

.FORECAST DAYS 3 THROUGH 5...
.SUNDAY NIGHT...PARTLY CLOUDY. SCATTERED SHOWERS AND THUNDERSTORMS IN
THE EVENING...THEN ISOLATED SHOWERS... THUNDERSTORMS AND SNOW
SHOWERS AFTER MIDNIGHT. LOWS IN THE MID 30S. SOUTHWEST WINDS 10-15
MPH...SHIFTING WEST TO NORTHWEST AROUND 11 MPH IN THE MID EVENING.
.MONDAY...COOLER. MOSTLY CLEAR. LOWS IN THE LOWER 30S. HIGHS IN
THE MID 60S. WEST WINDS AROUND 10 MPH.
.TUESDAY...CLEAR. LOWS IN THE MID 30S. HIGHS IN THE MID 70S.
WINDS GENERALLY LESS THAN 10 MPH.
.WEDNESDAY...MOSTLY CLEAR. LOWS IN THE MID 30S. HIGHS IN THE MID
70S. WINDS GENERALLY LESS THAN 10 MPH.
.THURSDAY...PARTLY CLOUDY WITH SLIGHT CHANCE OF SHOWERS...
THUNDERSTORMS AND SNOW SHOWERS. LOWS IN THE MID 30S. HIGHS IN THE
MID 70S. WINDS GENERALLY LESS THAN 10 MPH.

$$

FORECASTER...T.BAKER
REQUESTED BY...LAURA DOOLEY
REASON FOR REQUEST...WILDFIRE
.TAG 20100821.ARTHU.01/RIW