FNUS75 KRIW 282234
FWSRIW

SPOT FORECAST FOR ARNICA FIRE...NPS YNP
NATIONAL WEATHER SERVICE RIVERTON WY
434 PM MDT MON SEP 28 2009

FORECAST IS BASED ON REQUEST TIME OF 1553 MDT ON SEPTEMBER 28.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE.

.DISCUSSION...CLOUD COVER PUT A DAMPER ON WINDS THIS AFTERNOON.
VISIBLE SATELLITE SHOWED AN AREA OF CLEARING MOVING INTO THE WESTERN PORTION
OF THE PARK WITH MOSTLY CLEAR SKIES EXPECTED THROUGH 2300 BEFORE MORE
CLOUDS WORK THERE WAY IN. SURFACE OBSERVATIONS SHOWED SOME MIXING
OUT OF SOUTH SOUTHWEST WIND ACROSS THE WESTERN PORTION OF THE
PARK. EXPECT THE POTENTIAL FOR THESE SOUTH SOUTHWEST WINDS TO MIX
OUT OVER THE BURN AREA THROUGH SUNSET BEFORE WINDS DIMINISH.

SOUTHWEST FLOW WILL INCREASE TUESDAY AFTERNOON AHEAD OF A STRONG
COLD FRONT WITH THE FRONT EXPECTED TO MOVE THROUGH YELLOWSTONE
PARK AROUND MIDNIGHT TUESDAY...FOLLOWED BY MUCH COOLER
TEMPERATURES AND WIDESPREAD RAIN AND SNOW SHOWERS BY SUNRISE WEDNESDAY.


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

FORECASTER...MEUNIER

.TONIGHT...
SKY/WEATHER.........BECOMING MOSTLY CLEAR (10 PERCENT) UNTIL 2300 THEN
                    MOSTLY CLOUDY (70 PERCENT). AREAS OF SMOKE.
MIN TEMPERATURE.....33-36.
MAX HUMIDITY........60-70 PERCENT.
20 FOOT WINDS.......SOUTH SOUTHWEST WIND 5 TO 15 MPH WITH GUSTS 15 TO 20 MPH
                    THROUGH SUNSET...BECOMING SOUTH SOUTHEAST 4 TO 8 MPH
                    AFTERWARDS.
RIDGE TOP WINDS.....SOUTH 15 TO 20 MPH.
LAL.................1.
CHC OF WETTING RAIN.ZERO PERCENT.
HAINES INDEX........4 OR MODERATE POTENTIAL FOR LARGE PLUME
                    DOMINATED FIRE GROWTH.
MIXING HEIGHT.......4400 FT AGL DECREASING TO 2000 FT AGL AFTER
                    MIDNIGHT.
TRANSPORT WINDS.....SOUTH 17 TO 20 MPH.
SMOKE DISPERSAL.....POOR TO GOOD (30300-68600 KNOT-FT).

.TUESDAY...
SKY/WEATHER.........PARTLY CLOUDY (40-50 PERCENT). AREAS OF SMOKE
                    IN THE MORNING.
MAX TEMPERATURE.....59-62.
MIN HUMIDITY........19-22 PERCENT.
20 FOOT WINDS.......UPSLOPE/UPVALLEY 5-9 MPH BECOMING SOUTH SOUTHWEST 10
                    TO 15 MPH WITH GUSTS TO AROUND 25 MPH BETWEEN NOON
                    AND 1400.
RIDGE TOP WINDS.....SOUTH SOUTHWEST 10 TO 15 MPH IN THE MORNING
                    INCREASING TO 20 TO 35 MPH IN THE AFTERNOON.
LAL.................1.
CHC OF WETTING RAIN.ZERO PERCENT.
HAINES INDEX........5 OR MODERATE POTENTIAL FOR LARGE PLUME
                    DOMINATED FIRE GROWTH.
MIXING HEIGHT.......2800 FT AGL INCREASING TO 10800 FT AGL IN THE
                    AFTERNOON.
TRANSPORT WINDS.....SOUTHWEST 17 TO 22 MPH.
SMOKE DISPERSAL.....FAIR (43600 KNOT-FT) INCREASING TO EXCELLENT
                    (185700 KNOT-FT) IN THE AFTERNOON.

.FORECAST DAYS 3 THROUGH 5...
.TUESDAY NIGHT...CLOUDY. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS IN THE EVENING...THEN NUMEROUS SNOW SHOWERS AND
ISOLATED THUNDERSTORMS AFTER MIDNIGHT. LOWS IN THE UPPER 20S.
SOUTHWEST WINDS AROUND 11 MPH.
.WEDNESDAY...MUCH COLDER. NUMEROUS SNOW SHOWERS AND ISOLATED
THUNDERSTORMS. LOWS AROUND 17. HIGHS IN THE MID 30S. NORTHWEST
WINDS AROUND 10 MPH.
.THURSDAY...PARTLY CLOUDY WITH ISOLATED SNOW SHOWERS AND SHOWERS.
LOWS AROUND 15. HIGHS IN THE MID 30S. WINDS GENERALLY LESS THAN
10 MPH.
.FRIDAY...PARTLY CLOUDY WITH SLIGHT CHANCE OF SNOW SHOWERS. LOWS
IN THE LOWER 20S. HIGHS AROUND 40. WINDS GENERALLY LESS THAN
10 MPH.
.SATURDAY...PARTLY CLOUDY WITH SLIGHT CHANCE OF SHOWERS AND SNOW
SHOWERS. LOWS IN THE LOWER 20S. HIGHS IN THE LOWER 40S. WINDS
GENERALLY LESS THAN 10 MPH.

$$

FORECASTER...MEUNIER
REQUESTED BY...ED FOLTS
REASON FOR REQUEST...WILDFIRE
.TAG 20090928.ARNIC.01/RIW