Flash Flood Warning 6, NWS Riverton, WY

234 
WGUS75 KRIW 031447
FFSRIW

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
847 AM MDT SUN JUL 3 2011

WYC013-031500-
/O.CAN.KRIW.FF.W.0006.000000T0000Z-110704T1400Z/
/00000.0.SM.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FREMONT WY-
847 AM MDT SUN JUL 3 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR CENTRAL FREMONT 
COUNTY IS BEING CANCELED...

THE FLASH FLOOD WARNING HAS BEEN CANCELED.  WATERS IN THE LITTLE 
WIND RIVER HAVE RECEDED AND THIS TREND IS EXPECTED TO CONTINUE.

REPORT FLOODING TO THE NATIONAL WEATHER SERVICE OFFICE IN RIVERTON AT
1-800-211-1448.

LAT...LON 4303 10838 4299 10836 4300 10871 4296 10901
      4303 10903 4306 10875

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 AM MDT SUN JUL 3 2011

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

DRY AIR HAS MOVED IN BEHIND THE UPPER WAVE THAT BROUGHT
THUNDERSTORMS TO PORTIONS OF CENTRAL AND SOUTHERN WYOMING SATURDAY.
THE WARMING TREND CONTINUES TODAY AS RIDGE STRENGTHENS OVER THE
WESTERN CONUS.  STEEP MID LEVEL LAPSE RATE WILL ALLOW FOR ISOLATED
THUNDERSTORMS TODAY BUT COVERAGE WILL BE SPARSE AS MOISTURE WILL BE
SOMEWHAT LIMITED OVER MUCH OF THE AREA.  A PLUME OF SUBTROPICAL
MOISTURE WILL WRAP AROUND THE STRENGTHENING SOUTHWEST HIGH ON MONDAY
BRINGING INCREASED COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR
MONDAY AFTERNOON.  THIS INFLUX OF MOISTURE SHOULD KEEP CONVECTION
AROUND THROUGH THE NIGHT AND INTO TUESDAY.  INCREASED INSTABILITY
WILL BRING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS FOR TUESDAY
AFTERNOON AND EVENING.  THE GREATEST CHANCE COMING TO THE BIG HORN
BASIN AND JOHNSON AND NATRONA COUNTIES.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

MODELS CONTINUE TO BE IN FAIRLY GOOD AGREEMENT WEDNESDAY THROUGH
FRIDAY WITH THE UNSETTLED WEATHER PATTERN. THE MID AND UPPER LEVEL
MOISTURE WILL COME IN SURGES DURING THIS PERIOD AND THERE WILL BE
INCREASED CHANCES FOR THUNDERSTORMS WITH GUSTY WIND AND LOCALLY
HEAVY RAIN. SURFACE AND NEAR SURFACE DEWPOINT VALUES WILL ALSO BE
KEY TO THE RAIN POTENTIAL AND THE MODELS SEEM TO BRING IN SURGES OF
THAT AS WELL WED THROUGH FRI. THE GFS MODEL MAINTAINS AN UNSETTLED
SW FLOW ALOFT PATTERN SATURDAY AND NEXT SUNDAY WITH THE CHANCE OF
MORE STORMS. THE ECMWF MODEL PUSHES THE BETTER MOISTURE TO THE SOUTH
AND MAINLY OVER THE FAR SOUTH ZONES THOSE DAYS. THIS IS DUE TO A
STRONGER WEATHER SYSTEM MOVING THROUGH SOUTHERN CANADA AND PUSHING
THE RIDGE TO THE SOUTH. SOME GFSENSEMBLE MEMBERS AGREE WITH THE
ECMWF. WILL SEE HOW THINGS LOOK TONIGHT. FOR NOW HAVE KEPT THE
THUNDERSTORM CHANCE IN THE FORECAST SATURDAY AND NEXT SUNDAY.
TEMPERATURES WILL POSE A CHALLENGE DUE TO THE CLOUD COVER AND THE
EXPECTED STORM ACTIVITY. HAVE MADE MINOR CHANGES TO GOING FORECAST.
MOST HIGHS WILL BE IN THE 80S TO AROUND 90 WITH 60S AND 70S FOR THE
HIGH COUNTRY FROM WED THROUGH NEXT SUNDAY.

&&

.AVIATION...

VFR CONDITIONS ARE EXPECTED EXCEPT FOR AREAS NEAR ANY ISOLATED
AFTERNOON AND EARLY EVENING CONVECTION. A BUILDING RIDGE WILL LIMIT
CONVECTION TODAY...BUT INTENSE INSOLATION AND ADEQUATE MOISTURE
COULD RESULT IN VERY ISOLATED CONVECTION THIS AFTERNOON AND
EVENING...MAINLY OVER THE HIGHER TERRAIN AND ADJACENT FOOTHILLS. A
WEAK COLD FRONT IS EXPECTED TO PUSH SOUTH...EAST OF THE DIVIDE LATE
TONIGHT/MONDAY MORNING. THIS FRONT SHOULD MOVE ACROSS BIG HORN BASIN
AND JOHNSON COUNTY AFTER 06Z MONDAY...WITH ONLY A WIND SHIFT TO THE
NORTH/NORTHWEST EXPECTED.

&&

.FIRE WEATHER...

HOT AND DRY CONDITIONS ARE EXPECTED TODAY OVER WESTERN AND CENTRAL
WYOMING.  A FEW HIGH BASED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON
BUT THE MAINLY DRY CONDITIONS WILL KEEP THE COVERAGE TO A MINIMUM.
HUMIDITIES TODAY WILL RANGE FROM THE LOW TEENS TO LOW 20S.  COOLER
TEMPERATURES AND INCREASING MOISTURE IS EXPECTED ACROSS THE AREA FOR
MONDAY AND TUESDAY INCREASING LOW LEVEL HUMIDITY AND COVERAGE OF
SHOWERS AND THUNDERSTORMS.

&&

.HYDROLOGY...

HOTTER TEMPERATURES WILL CONTINUE THE SNOWMELT IN THE MOUNTAINS OF
WESTERN AND CENTRAL WYOMING TODAY.  THE SNOWPACK HAS MOSTLY MELTED
BELOW 9500 FEET IN THE BIGHORNS WHILE SOME SIGNIFICANT SNOWPACK
REMAINS IN AREAS OF THE WEST.  MOST RIVERS AND STREAMS WILL BEGIN TO
RECEDE BY EARLY IN THE WEEK AS THE AREAS COVERAGE OF SNOW
DECREASES.  SIGNIFICANT RAIN IS NOT EXPECTED TODAY BUT SHOWERS AND
THUNDERSTORMS WILL INCREASE IN COVERAGE MONDAY AND TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

SHORT TERM...BERC
LONG TERM...AR
AVIATION...WM
FIRE WEATHER...BERC
HYDROLOGY...BERC

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
400 AM MDT SUN JUL 3 2011

WYZ001>020-022>030-041200-
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-
400 AM MDT SUN JUL 3 2011

...FLOOD WARNING FOR THE WIND RIVER FROM DUBOIS TO RIVERTON AND
FOR SMALLER CREEKS AND RIVERS OF BIG HORN...SUBLETTE...AND PARK
COUNTIES...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING...MAINLY ACROSS MOUNTAINOUS AREAS. GUSTY WIND WILL BE THE
PRIMARY THREAT WITH ANY THUNDERSTORMS.

EXCESSIVE SNOWMELT DUE TO WARM TEMPERATURES WILL CONTINUE TO CAUSE
HIGH WATER LEVELS ON THE WIND RIVER FROM FROM DUBOIS THROUGH
RIVERTON. FLOODING WILL CONTINUE IN LOW LYING AREAS ADJACENT TO THE
WIND RIVER.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

CREEKS AND RIVERS WILL CONTINUE TO RUN HIGH AND SWIFT THROUGH AT
LEAST TUESDAY AS THE HIGH MOUNTAIN SNOWPACK CONTINUES TO MELT. THE
WIND RIVER...SHOSHONE RIVER...GREYBULL RIVER...GREEN RIVER...BLACKS
FORK RIVER...NORTH FORK OF THE POPO AGIE...AND THE BIG HORN RIVER
WILL BE MOST SUSCEPTIBLE TO THE HIGH RUNOFF. EXERCISE CAUTION NEAR
FAST FLOWING RIVERS AS THE CURRENT WILL BE DANGEROUS AND DEBRIS WILL
BE FLOWING IN THE CHANNEL.

THUNDERSTORM COVERAGE WILL BE ON THE INCREASE FROM MONDAY THROUGH AT
LEAST THURSDAY AS THE WEATHER PATTERN CHANGES TO A MORE UNSETTLED
SCENARIO.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT SEVERE WEATHER AND FLOODING TO THE
NATIONAL WEATHER SERVICE AT 1-800-211-1448. THANK YOU.

TEAM RIVERTON