Red Flag Warning 4, NWS Riverton, WY

000 
WWUS85 KRIW 271405
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
805 AM MDT SUN SEP 27 2009

...RED FLAG WARNING FOR THE LOWER ELEVATIONS OF SWEETWATER...
SUBLETTE...UINTA AND SOUTHERN LINCOLN COUNTIES FROM NOON TODAY
THROUGH 9 PM THIS EVENING...

.NORTHWEST FLOW BEHIND A DEPARTING TROUGH WILL BRING GUSTY WEST
TO NORTHWEST WINDS TODAY ACROSS SOUTHWEST WYOMING.  THESE WINDS
WILL COMBINE WITH VERY LOW RELATIVE HUMIDITIES AND CRITICALLY DRY
FUELS TO CREATE RED FLAG CONDITIONS THIS AFTERNOON AND EVENING. 
ALSO...A COLD FRONT WILL MOVE IN THIS EVENING WITH A SHARP WIND
SHIFT FROM THE NORTHEAST.

WYZ277>279-280300-
/O.CON.KRIW.FW.W.0004.090927T1800Z-090928T0300Z/
LINCOLN AND UINTA COUNTIES / LOWER ELEVATIONS-
UPPER GREEN RIVER BASIN / ROCK SPRINGS BLM-
SWEETWATER COUNTY / ROCK SPRINGS BLM / FLAMING GORGE NRA-
805 AM MDT SUN SEP 27 2009

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING...

THIS INCLUDES THE FOLLOWING FIRE WEATHER ZONES... 
IN WYOMING...277...278...279

WEST TO NORTHWEST WINDS OF 10 TO 15 MPH WITH GUSTS TO 25 MPH...
ALONG WITH VERY LOW RELATIVE HUMIDITY VALUES OF BELOW 15 PERCENT
ARE EXPECTED THIS AFTERNOON AND EVENING. THESE WEATHER CONDITIONS
WILL COMBINE WITH CRITICALLY DRY FUELS TO PRODUCE RED FLAG
CONDITIONS THIS AFTERNOON AND EVENING ACROSS MUCH OF SOUTHWEST
WYOMING. A COLD FRONT WILL MOVE IN THIS EVENING PRODUCING AN
ABRUPT WIND SHIFT FROM THE NORTHEAST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS
ARE EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF
STRONG WINDS...LOW RELATIVE HUMIDITY...AND WARM TEMPERATURES WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

&&

$$

000 
WWUS85 KRIW 280225
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
825 PM MDT SUN SEP 27 2009


WYZ277>279-280330-
/O.CAN.KRIW.FW.W.0004.000000T0000Z-090928T0300Z/
LINCOLN AND UINTA COUNTIES / LOWER ELEVATIONS-
UPPER GREEN RIVER BASIN / ROCK SPRINGS BLM-
SWEETWATER COUNTY / ROCK SPRINGS BLM / FLAMING GORGE NRA-
825 PM MDT SUN SEP 27 2009

...RED FLAG WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS CANCELLED THE RED
FLAG WARNING. 

THIS INCLUDES THE FOLLOWING FIRE WEATHER ZONES...
IN WYOMING...277...278...279

THE COLD FRONT HAS MOVED THROUGH MOST OF THE AREA. ALSO...WINDS
HAVE SLACKENED AND RHS HAVE RISEN ABOVE RED FLAG CRITERIA.
THEREFORE...THE RED FLAG WARNING HAS BEEN CANCELLED.

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 PM MDT SAT SEP 26 2009

.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT

DRY AND BREEZY CONDITIONS WILL PREVAIL TONIGHT ACROSS WESTERN AND
CENTRAL WYOMING. A DRY CANADIAN COLD FRONT WILL PUSH SOUTH FROM MONTANA
ACROSS NORTHERN AND CENTRAL WYOMING THROUGH THE DAY SUNDAY
BRINGING COOLER TEMPERATURES...NORTH NORTHEAST WIND AND HIGHER
HUMIDITY. AN UPPER LEVEL HIGH PRESSURE RIDGE WILL THEN BUILD OVER
WYOMING THROUGH MONDAY WITH THE RIDGE AXIS SHIFTING EAST OF THE
AREA ALLOWING WARMER SOUTHWEST WINDS TO RETURN TO THE AREA. AHEAD
OF A PACIFIC LOW PRESSURE TROUGH MOVING INTO THE WEST COAST. WIND
SHOULD KEEP AIR MASS MIXED MONDAY NIGHT AND HAVE BOOSTED
TEMPERATURES SOME EAST OF THE CONTINENTAL DIVIDE IN RESPONSE TO THE
BREEZE.

.LONG TERM...TUESDAY THROUGH SATURDAY

A SIGNIFICANT TROUGH WILL AFFECT THE FORECAST AREA TUESDAY THROUGH
THURSDAY. EARLY THIS MORNING...WATER VAPOR IMAGERY SHOWS THIS
TROUGH OVER WESTERN ALASKA SOUTH ACROSS THE ALEUTIAN ISLANDS...AND
THE NORTHERN PACIFIC. AHEAD OF THIS TROUGH ON TUESDAY...DEEP
SOUTHWEST FLOW IS EXPECTED ACROSS THE REGION. THESE WINDS AND A
LEE TROUGH DEVELOPING WILL RESULT IN BREEZY TO LOCALLY WINDY
CONDITIONS TUESDAY AFTERNOON AND EVENING. SOME DIFFLUENT FLOW
AHEAD OF THE SYSTEM AND INCREASED MID LEVEL MOISTURE SHOULD ALLOW
FOR ISOLATED CONVECTION...MAINLY WEST OF THE DIVIDE. MEDIUM RANGE
MODELS IN DECENT AGREEMENT IN BRINGING THE STRONG COLD FRONT
THROUGH LATE TUESDAY NIGHT AND DURING THE DAY ON WEDNESDAY. SNOW
LEVELS ARE EXPECTED TO DROP TO ABOUT 8500 FEET OVER THE EXTREME
WEST BY 12Z WEDNESDAY. MEDIUM RANGE MODELS ARE SHOWING SOME
SPLITTING WITH THE TROUGH WITH THE SOUTHERN ENERGY MOVING ACROSS
UTAH AND COLORADO...WITH THE ECMWF A BIT FARTHER SOUTH AND A BIT
SLOWER DURING WEDNESDAY AND THURSDAY. REGARDLESS THERE IS A GOOD
CHANCE FOR PRECIPITATION WEDNESDAY THROUGH THURSDAY MORNING. BOTH
MODELS INDICATE 700MB TEMPS DROPPING DOWN TO BETWEEN -6 AND -9 DEG
CELSIUS BY 12Z THURSDAY...WHICH WOULD MEAN THAT MOST AREAS WOULD BE
SEEING SNOWFALL IF PRECIP OCCURS. LOOKS LIKE DECENT UPSLOPE
CONDITIONS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. THIS SYSTEM
WILL NEED TO BE WATCHED FOR THE POSSIBILITY OF SIGNIFICANT
SNOWFALL FOR THE MOUNTAINS...AND EVEN THE POSSIBILITY OF THE FIRST
SNOWFALL FOR THE LOWER ELEVATIONS. HOWEVER...THIS WILL DEPEND ON
THE DETAILS OF THIS SYSTEM WHICH WILL BECOME CLEARER IN THE COMING
DAYS. HAVE GONE BELOW MEX MOS GUIDANCE BOTH WEDNESDAY AND
THURSDAY...BASED ON 700 MB TEMPS AND THE INCLEMENT WEATHER
EXPECTED. AFTER THURSDAY...COOL AND MAINLY DRY CONDITIONS ARE
EXPECTED. ANOTHER SYSTEM WILL APPROACH THE REGION ON
SATURDAY...AND WILL HAVE SLIGHT POPS ACROSS THE WEST FOR THIS
SYSTEM.

&&

.AVIATION...
VFR CONDITIONS CAN BE EXPECTED THROUGH SUNDAY. WEST WINDS OF 20 TO
35 MPH CAN BE EXPECTED OVER MUCH OF THE AREA THROUGH THIS EVENING
WITH LIGHTER WIND SPEEDS EXPECTED OVER THE BASINS...VALLEYS AS WELL
AS OVER JOHNSON COUNTY. A WIND SHIFT TO THE NORTH IS EXPECTED EAST
OF THE DIVIDE TONIGHT AS A COLD FRONT PUSHES SOUTH OVER THE AREA.

&&

.FIRE WEATHER...
A STRONG JET STREAM WILL MOVE EAST ACROSS SOUTH CANADA THIS EVENING.
THE ASSOCIATED INCREASING WIND AT MOUNTAINTOP LEVEL AND ABOVE
WILL KEEP SURFACE WIND UP THROUGH THE EVENING. THE INCREASING WIND
WILL COMBINE WITH A VERY DRY AND WARM AIRMASS TO CREATE RED FLAG
CONDITIONS IN FIRE WEATHER ZONES 140...277...278...279...286...AND
288 UNTIL 9 PM MDT. OTHER AREAS WILL EXPERIENCE HEIGHTENED FIRE
WEATHER CONDITIONS WITH BREEZY WIND AND LOW RELATIVE HUMIDITY LEVELS
IN THE TEENS. A DRY BACKDOOR COLD FRONT WILL MOVE THROUGH CENTRAL
WYOMING ON SUNDAY. COOLER TEMPERATURES ALONG WITH SLIGHTLY HIGHER
RELATIVE HUMIDITY LEVELS ARE EXPECTED EAST OF THE DIVIDE SUNDAY.
DRY AND BREEZY CONDITIONS WILL CONTINUE WEST OF THE DIVIDE SUNDAY
AFTERNOON BUT WITH LESS WIND...SLIGHTLY COOLER TEMPERATURES...ONLY
LOCAL CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ140-277>279-
286-288.

&&

SHORT TERM...C.BAKER
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...C.BAKER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
914 PM MDT SAT SEP 26 2009

WYZ001>020-022>030-271200-
ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST-
BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY-
TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN-
WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
YELLOWSTONE NATIONAL PARK-
914 PM MDT SAT SEP 26 2009

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

A WINTER-LIKE STORM SYSTEM WITH THE POTENTIAL FOR SIGNIFICANT
SNOWFALL IN THE MOUNTAINS...IS EXPECTED TO AFFECT WESTERN AND CENTRAL
WYOMING TUESDAY NIGHT THROUGH THURSDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

TEAM RIVERTON