Flash Flood Warning 6, NWS Riverton, WY

745 
WGUS75 KRIW 252219
FFSRIW

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
419 PM MDT SUN MAY 25 2014

WYC025-252232-
/O.CAN.KRIW.FF.W.0006.000000T0000Z-140526T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NATRONA WY-
419 PM MDT SUN MAY 25 2014

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR EAST CENTRAL
NATRONA COUNTY IS CANCELLED...

EMERGENCY MANAGEMENT REPORTED THAT NO FLOODING WAS OBSERVED IN THE 
AREA AT 415 PM AND RAIN HAD ENDED...ENDING THE FLOOD THREAT. IF 
FLOODING HAS BEEN OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW 
ENFORCEMENT AGENCY.

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

LAT...LON 4270 10617 4274 10626 4286 10619 4285 10606
      4280 10607

$$

MEUNIER

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
306 PM MDT SUN MAY 25 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

CONVECTION IS POPPING OVER EASTERN SWEETWATER COUNTY...FAR
SOUTHEAST FREMONT COUNTY...SOUTHEAST NATRONA COUNTY INCLUDING
CASPER AS WELL AS THE SOUTHERN BIG HORN MTNS. THE NORTHWEST BACK
EDGE OF THIS AREA OF CONVECTION IS ABOUT EXACTLY WHERE THE
TRANSITION FROM NEGATIVE TO POSITIVE LIFTED INDICES WAS PROGGED BY
THE GFS FOR THIS AFTERNOON. IN REALITY...THE BEST CELLS ARE
POPPING WHERE THE LIFTED INDICES RANGE FROM -1 TO -4 AS OPPOSED TO
PLUS ONE TO MINUS 2 TO THE NORTH AND WEST OF THE CONVECTION.
HIGHEST CAPES ARE AROUND CASPER AND FAR SOUTHEAST SWEETWATER CO.
THESE SLOW MOVING LOCALLY HEAVY RAINERS WILL LINGER INTO THE
EVENING.

THIS TREND WILL CONTINUE WITH THE BEST CONVECTION SLIDING OFF TO
THE SOUTHEAST AS THE GENERAL FLOW SHIFTS FROM EAST AND
NORTHEASTERLY TO WESTERLY LATE TONIGHT AS THE STUBBORN UPPER LOW
MOVES EAST ALONG THE NM/CO BORDER AND THE ASSOCIATED COL REGION
SLIDES OFF TO THE EAST OF US. THE TREND FOR HOTTER AND DRIER
CONDITIONS WILL BEGIN MONDAY WITH HIGH TEMPERATURES STEADILY
RISING THROUGH WEDNESDAY WHEN HIGHS REACH 90 AT SOME LOWER
ELEVATIONS EAST OF THE DIVIDE AND 75 TO 80 WEST...HOTTEST
TEMPERATURES OF THE SEASON SO FAR AS THE HOTTER DRIER AIR MOVES IN
FROM THE WEST. ONLY ISOLATED THUNDERSTORMS...MAINLY OVER THE NORTHERN
MOUNTAINS...ARE EXPECTED MONDAY. BY WEDNESDAY...THE MINIMUM RH WILL
BE DOWN IN THE UPPER SINGLE DIGITS TO LOW TEENS WHICH WILL ELEVATE
THE POTENTIAL FIRE DANGER IN SOUTHERN WYOMING AND IN THE WIND
RIVER BASIN.

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY

NO MAJOR CHANGES IN THE FORECAST PACKAGE WITH THE 12Z RUNS OF THE
GFS AND ECMWF TODAY. A RIDGE CONTINUES TO BUILD OVER THE NORTHERN
ROCKIES AND NORTHERN PLAINS BY WEDNESDAY...IN RESPONSE TO A CLOSED
LOW MOVING ONSHORE OVER THE PACIFIC NORTHWEST. THERE ARE SOME TIMING
ISSUES BETWEEN THE GFS AND ECMWF...BUT BOTH MODELS FORECAST THIS
SYSTEM TO MOVE INTO SOUTHERN ALBERTA. WARM...BREEZY SOUTHWEST WINDS
WILL BE THE RESULT FOR THE FORECAST AREA FROM THIS SYSTEM. THE COLD
FRONT ASSOCIATED WITH THIS SYSTEM...WILL BECOME STATIONARY ACROSS
CENTRAL PORTIONS...EXTENDING FROM SHERIDAN COUNTY TO EASTERN
SWEETWATER COUNTY BY THURSDAY AFTERNOON. ANY CONVECTIVE ACTIVITY
GENERATED BY THIS BOUNDARY WILL BE ISOLATED AT BEST...DUE TO LIMITED
MOISTURE.

THIS WILL BE SHORT-LIVED...AS THE REMNANTS OF A TROPICAL SYSTEM
QUICKLY MOVES NORTHWARD OVER THE FOUR CORNERS AREA THURSDAY
AFTERNOON...AND INTO WYOMING BY NOON FRIDAY. EVEN WITH INCREASED
CLOUD COVER...THERE SHOULD BE ENOUGH INSTABILITY FOR CONVECTION TO
DEVELOP. HAVE BROAD BRUSHED POPS ACROSS THE FORECAST AREA...BUT
STRONGER STORMS SHOULD BE CONFINED ACROSS EASTERN AND CENTRAL
PORTIONS.

AS THIS SYSTEM BEGINS TO EXIT EASTWARD OUT OF THE AREA...ANOTHER
TROUGH DIGS ALONG THE COAST AND MOVES ONSHORE OVER NORTHERN
CALIFORNIA SATURDAY MORNING. THERE WILL BE ENOUGH RESIDUAL MOISTURE
LEFT OVER FROM FRIDAY FOR ADDITIONAL THUNDERSTORMS...AS A WARM FRONT
ASSOCIATED WITH THE TROUGH MOVES NORTHWARD. MOIST SOUTHERLY FLOW
WILL OCCUR FOR SUNDAY...AS THE TROUGH SLOWLY MAKES ITS WAY ACROSS
THE GREAT BASIN.

&&

.AVIATION.../00Z ISSUANCE/

&&

.HYDROLOGY...

RAIN FROM THE SLOW MOVING THUNDERSTORMS OVER THE LAST COUPLE DAYS
HAS RESULTED IN SATURATED SOILS AND RIVER RISES ACROSS THE AREA.
OVER THE NEXT FEW DAYS...RIVERS MAY HAVE ADDITIONAL RISES. THERE
IS PARTICULAR CONCERN OVER THE THUNDERSTORMS LATE TODAY AND
TONIGHT OVER EASTERN PORTIONS OF THE FORECAST AREA AS THEY ARE
SLOW MOVING AND HAVE THE POTENTIAL TO DROP A LARGE AMOUNT OF RAIN
IN A SHORT PERIOD OF TIME. THE BEST CHANCE FOR HEAVY RAIN REMAINS
OVER NATRONA COUNTY AND SOUTHERN JOHNSON COUNTY BUT THE GENERAL
SOUTHWEST TRACK OF THE STORMS AND NEARLY STATIONARY FLOW OVER THE
BIGHORNS LED US TO INCLUDE THE BIGHORNS AND THE EASTERN BIGHORN
BASIN IN THE FLASH FLOOD WATCH AS WELL. THUNDERSTORM ACTIVITY
DECREASES AFTER TODAY.

THE WORK WEEK WILL FEATURE A WARMING TREND THROUGH WEDNESDAY OR
THURSDAY WITH TEMPERATURES POTENTIALLY RISING INTO THE 90S...THIS
SHOULD REALLY BEGIN TO BRING DOWN A LOT OF WATER IN THE HIGHER
ELEVATION SNOW PACK. THE LONG RANGE MODELS ARE ALSO HINTING AT A
TROPICAL SYSTEM MOVING INTO THE REGION LATE FRIDAY INTO
SATURDAY...WHICH COULD BRING MORE RAIN ON TOP OF A VERY RIPE SNOW
PACK AND SWOLLEN RIVERS. RESIDENTS NEAR RIVERS ARE ENCOURAGED TO
STAY AWARE OF CURRENT LEVELS AND TAKE NEEDED PRECAUTIONS IF RIVER
LEVELS RISE TO BANKFULL OR BEGIN TO FLOOD.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT
WYZ004-006-008>011-019-020-022.

&&

SHORT TERM...LIPSON
LONG TERM...LAVOIE
AVIATION...LIPSON
HYDROLOGY...ALLEN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MDT SUN MAY 25 2014

WYZ001>020-022>030-261200-
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-
242 PM MDT SUN MAY 25 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

...A FLASH FLOOD WATCH IS IN EFFECT FOR PORTIONS OF EAST CENTRAL
WYOMING THROUGH MIDNIGHT...

.DAY ONE...TODAY AND TONIGHT

ANOTHER ROUND OF AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE. GUSTY WIND...SMALL HAIL...AND PERIODS OF HEAVY RAINFALL
WILL BE POSSIBLE WITH STORM DEVELOPMENT. SOME RIVERS AND STREAMS
ACROSS THE AREA HAVE ALREADY BEEN IMPACTED BY PAST SLOW MOVING
THUNDERSTORMS...AND MAY SEE ADDITIONAL RAINFALL TODAY. CONDITIONS
FOR FLOODING WILL BE MONITORED AND NEARBY RESIDENTS SHOULD PAY
ATTENTION TO RISING RIVER LEVELS AND TAKE APPROPRIATE ACTION.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

MONDAY THROUGH WEDNESDAY...WARMER. ISOLATED THUNDERSTORMS EACH
AFTERNOON AND EVENING. BREEZY TO WINDY TUESDAY AND WEDNESDAY WITH
INCREASED FIRE DANGER FOR THE LOWER ELEVATIONS OF THE SOUTHWEST AND
CENTRAL PORTIONS OF THE FORECAST AREA. THIS WILL ALSO INCREASE HIGH
ELEVATION SNOWMELT TUESDAY AND WEDNESDAY.

THURSDAY...BREEZY TO WINDY AREAS AND STILL WARM ACROSS THE CENTRAL
AND SOUTH. SLIGHTLY COOLER OVER THE NORTH AND WEST. ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS.

FRIDAY...A CHANCE OF SHOWERS AND THUNDERSTORMS AND COOLER.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS SHOULD REPORT ANY HAIL OR WIND GUSTS OF 40 MPH OR
HIGHER...AS WELL AS ANY FLOODING AND RAINFALL AMOUNTS. THANK YOU.

TEAM RIVERTON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
1212 PM MDT SUN MAY 25 2014

WYZ004>011-014-015-017>020-022-028>030-252000-
BIGHORN MOUNTAINS SOUTHEAST-BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-WIND RIVER BASIN-
WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
1212 PM MDT SUN MAY 25 2014

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO INCREASE IN
COVERAGE OVER THE NEXT COUPLE OF HOURS. MODERATE TO HEAVY RAIN MAY
OCCUR WITH UP TO ONE HALF INCH OF RAIN POSSIBLE IN SOME LOCATIONS
ALONG WITH SMALL HAIL AND FREQUENT LIGHTNING.

IF PLANNING OUTDOOR ACTIVITIES TODAY...PLEASE REMAIN WEATHER AWARE
AND IF YOU HEAR THUNDER PLEASE SEEK SHELTER. ALSO...THERE IS A
HEIGHTENED RISK OF FLASH FLOODING WITH THE STORMS TODAY...ESPECIALLY
ACROSS NATRONA COUNTY.

COUNTY ROADS AND DIRT ROADS IN THE AREA MAY SEE SOME PONDING OF WATER
OR WATER CROSSING OVER THE ROAD WHERE HEAVIER RAIN DOES FALL. REPORT
ANY FLOODING TO LOCAL LAW ENFORCEMENT OR TO THE NATIONAL WEATHER
SERVICE AT 1-800-211-1448.

19

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RIVERTON WY
219 PM MDT SUN MAY 25 2014

WYZ004>011-014-015-017>020-022-028>030-252200-
BIGHORN MOUNTAINS SOUTHEAST-BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-WIND RIVER BASIN-
WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
219 PM MDT SUN MAY 25 2014

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO INCREASE IN
COVERAGE OVER THE NEXT COUPLE OF HOURS. MODERATE TO HEAVY RAIN MAY
OCCUR WITH UP TO ONE HALF INCH OF RAIN POSSIBLE IN SOME LOCATIONS
ALONG WITH SMALL HAIL AND FREQUENT LIGHTNING.

SOME OF THE THUNDERSTORMS WITH THE HEAVIEST RAINFALL AND MOST
FREQUENT LIGHTNING HAVE BEEN OBSERVED 5 TO 10 MILES SOUTHWEST OF
CASPER.

BOATERS OUT ON ALCOVA AND PATHFINDER RESERVOIRS IN SOUTHERN NATRONA
COUNTY AS WELL AS 5 MILES EAST OF FLAMING GORGE RESERVOIR IN
SWEETWATER COUNTY WILL NEED TO HEAD TO SHORT AT THE FIRST SIGN OF
THREATENING WEATHER.

SINCE THESE STORMS ARE MOVING QUITE SLOWLY...THE RESIDENCE
TIME WITH ANY ONE OF THESE STORMS WILL ALLOW TIME FOR THE RAINFALL TO
ADD UP TO ONE HALF INCH IN LOCAL AREAS.

IF PLANNING OUTDOOR ACTIVITIES TODAY...PLEASE REMAIN WEATHER AWARE
AND IF YOU HEAR THUNDER PLEASE SEEK SHELTER. ALSO...THERE IS A
HEIGHTENED RISK OF FLASH FLOODING WITH THE STORMS TODAY...ESPECIALLY
ACROSS NATRONA COUNTY.

COUNTY ROADS AND DIRT ROADS IN THE AREA MAY SEE SOME PONDING OF WATER
OR WATER CROSSING OVER THE ROAD WHERE HEAVIER RAIN DOES FALL. REPORT
ANY FLOODING TO LOCAL LAW ENFORCEMENT OR TO THE NATIONAL WEATHER
SERVICE AT 1-800-211-1448.

LIPSON