904
FXUS65 KRIW 192334
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
530 PM MDT FRI AUG 19 2022
SHORT TERM
THIS AFTERNOON THROUGH SATURDAY NIGHT
ISSUED AT 1041 AM MDT FRI AUG 19 2022
THE COWBOY STATE WILL GET SQUEEZED BETWEEN TWO WEATHER FEATURES
TODAY: A CLOSED LOW MOVING SOUTH OVER THE NORTHERN PLAINS/UPPER
MIDWEST WILL BRING A BACK DOOR COLD FRONT THROUGH AREAS EAST OF THE
DIVIDE AND A WEAK UPPER LOW OVER NORTHERN PORTIONS OF THE GREAT
BASIN WILL HELP ADVECT ANOTHER WAVE OF MONSOONAL MOISTURE INTO AREAS
WEST OF THE DIVIDE. NORTH TO NORTHEAST WINDS EAST OF THE DIVIDE AND
EAST TO SOUTHEAST WINDS OVER SOUTHERN PORTIONS WILL CONTINUE TODAY.
THIS WILL MAKE THE TIMING OF THE FRONT HARD TO IDENTIFY, AS THESE
WIND DIRECTIONS ARE INDICATIVE OF FROPA. ADDITIONALLY, THIS FRONT IS
WEAK AND ANY "COLD" AIR WILL BE CONFINED TO JOHNSON COUNTY. WITH ALL
THAT SAID, THE FRONT SHOULD PASS THROUGH EASTERN AND SOUTHERN
PORTIONS THIS AFTERNOON THROUGH TONIGHT. TEMPERATURES TODAY WILL BE
COOLER AS A RESULT, WITH HIGHS IN THE LOWER TO MIDDLE 80S FOR MUCH
OF THE CWA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
OCCUR OVER WESTERN PORTIONS THIS AFTERNOON AND EVENING, WITH
LINGERING SHOWERS POSSIBLE OVER SOUTHERN LINCOLN COUNTY AND THE
WESTERN HALF OF SWEETWATER COUNTY TONIGHT. THE LATTER SHOWERS ARE
EXPECTED TO END AFTER MIDNIGHT. PRECIPITABLE WATER (PWAT) VALUES ON
THE 12Z RIW SOUNDING ARE 0.74", SO LOCALLY HEAVY RAIN AND/OR
LOCALIZED FLASH FLOODING COULD OCCUR WITH THESE STORMS TODAY. WEAK
STEERING FLOW AND SLOW STORM MOTION WILL ALSO CONTRIBUTE TO THIS
HAZARD. LAST BUT NOT LEAST, SMOKE FROM WILDFIRES IN ID WILL RESULT
IN A SLIGHT HAZE OVER THE CENTRAL BASINS AND WESTERN PORTIONS TODAY.
THE OVERALL PATTERN CHANGES VERY LITTLE SATURDAY. THE UPPER HIGH
THAT GETS SQUEEZED TODAY WILL MOVE OVER EASTERN MT. THIS WILL HELP
KEEP THE UPPER FLOW IN A MORE EASTERLY DIRECTION, AT LEAST OVER
AREAS EAST OF THE DIVIDE. SHORTWAVES OVER UT, ASSOCIATED WITH THE
MONSOONAL SURGE OVER THE FOUR CORNERS, WILL PUSH NORTHWARD TOWARD
SOUTHWESTERN WY. THIS WILL TURN MID LEVEL WINDS IN A MORE SOUTHERLY
DIRECTION ACROSS AREAS WEST OF THE DIVIDE, ESPECIALLY ACROSS
SOUTHERN PORTIONS. THESE DIFFERING WIND FLOWS, COMBINED WITH THE
PROXIMITY OF THE APPROACHING SHORTWAVE, WILL KEEP SHOWERS AND
THUNDERSTORMS CONFINED WEST OF THE DIVIDE ONCE AGAIN. THIS
CONVECTIVE ACTIVITY LOOKS TO BE MORE ISOLATED/WIDELY SCATTERED
COMPARED TO TODAY, LIKELY A RESULT OF THE INFLUENCE OF THE UPPER
HIGH. PWATS ARE FORECASTED TO REMAIN BETWEEN 0.6 AND 0.8", SO THE
THREAT FOR LOCALLY HEAVY RAIN/LOCALIZED FLASH FLOODING WILL
CONTINUE. HIGHS WILL BE SLIGHTLY COOLER WEST OF THE DIVIDE, LIKELY A
RESULT OF INCREASED CLOUD COVER; HIGHS WILL BE IN THE MID 80S AGAIN
ACROSS CENTRAL PORTIONS, WHILE TEMPERATURES INCREASE TO THE UPPER
80S TO LOWER 90S OVER NORTHERN PORTIONS. THE SMOKE FROM THE ID
WILDFIRES LOOK TO HAVE LESS OF AN IMPACT SATURDAY.
LONG TERM
SUNDAY THROUGH FRIDAY
ISSUED AT 154 PM MDT FRI AUG 19 2022
THERE IS LITTLE CHANGE TO THE EXTENDED FORECAST. MOISTURE OVER
WESTERN WYOMING SUNDAY WILL ALLOW FOR SCATTERED SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING, ESPECIALLY FOR THE
NORTHWEST. EAST OF THE DIVIDE MAY SEE AN ISOLATED SHOWER OR
THUNDERSTORM, WITH THE BEST CHANCES BEING OVER HIGHER ELEVATIONS.
THE DIURNALLY DRIVEN ACTIVITY DIES DOWN SUNDAY NIGHT, AS A LOW
PRESSURE SYSTEM MOVES INTO THE WASHINGTON AREA. WITH THIS SYSTEM,
MOISTURE IS SHIFTED OVER THE NORTHERN HALF OF WYOMING FOR MONDAY.
AS A RESULT, SCATTERED CONVECTION FOR NORTHWESTERN AND NORTHERN
WYOMING WILL OCCUR AGAIN IN THE AFTERNOON AND EVENING HOURS,
POTENTIALLY LINGERING A BIT AFTER MIDNIGHT. THE BEST CHANCES FOR
PRECIP ON MONDAY WILL BE CENTERED OVER THE ABSAROKAS AND NORTHERN
WIND RIVER MOUNTAINS.
TUESDAY AND WEDNESDAY WILL BE VERY SIMILAR TO ONE ANOTHER, AS THE
SLOW MOVING SYSTEM TRACKS TOWARDS MONTANA. MOISTURE WILL REMAIN
BEST OVER THE NORTHERN HALF OF WYOMING THESE DAYS, WITH SCATTERED
SHOWERS AND THUNDERSTORMS FOR THE AFTERNOONS AND EVENINGS.
ISOLATED CONVECTION IS EXPECTED ELSEWHERE, WITH SWEETWATER COUNTY
LIKELY REMAINING THE DRIEST. THURSDAY AND FRIDAY LOOK TO HAVE THE
MOST WIDESPREAD SHOWER AND STORM ACTIVITY FOR THE CWA, WITH
NORTHERN WYOMING, AGAIN, HAVING THE BEST CHANCES.
TEMPERATURES FOR THE PERIOD WILL BE WARMEST SUNDAY, WITH UPPER 80S
TO MIDDLE 90S EAST OF THE DIVIDE AND UPPER 70S TO LOWER 80S FOR
THE WEST. MONDAY WILL SEE HIGH TEMPERATURES ONLY DROP A COUPLE
DEGREES. A COOLING TREND WILL CONTINUE THROUGH FRIDAY, ESPECIALLY
EAST OF THE DIVIDE. HIGHS WILL BE AROUND 80 FOR MOST OF THE CWA
BY FRIDAY.
AVIATION
FOR THE 00Z TAFS THROUGH 00Z SUNDAY
ISSUED AT 530 PM MDT FRI AUG 19 2022
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD, WITH A SLIGHT CHANCE
OF MVFR UNDER AND AROUND THUNDERSTORMS. SHOWERS AND THUNDERSTORMS
WILL CONTINUE ACROSS WESTERN WYOMING THROUGH THIS EVENING, ENDING
BETWEEN 02-03Z GENERALLY, WITH ACTIVITY ACROSS FAR SW WY THROUGH
06Z. THESE STORMS WILL SLOWLY MOVE SOUTH-SOUTHWEST FOR A VERY GOOD
CHANCE OF BRIEF HEAVY RAIN. KBPI, KJAC, KPNA, AND KRKS HAVE VCTS
CONTINUING AS A RESULT. GUSTY WINDS TO 40 KNOTS COULD OCCUR NEAR ANY
SHOWER OR THUNDERSTORM. KRIW MAY SEE SOME OF THIS OUTFLOW AS A
NORTHWEST WIND THIS EVENING. THERE IS ANOTHER CHANCE FOR SHOWERS AND
THUNDERSTORMS SATURDAY AFTERNOON AND EVENING ACROSS WESTERN WYOMING,
PRIMARILY AT KJAC AND KRKS. GENERAL ENE FLOW WILL CONTINUE SATURDAY
AS WELL.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
FIRE WEATHER
ISSUED AT 1041 AM MDT FRI AUG 19 2022
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR WESTERN
PORTIONS THIS AFTERNOON AND EVENING. LOCALLY HEAVY RAIN AND/OR
LOCALIZED FLASH FLOODING WILL BE POSSIBLE WITH THESE STORMS, DUE TO
ASSOCIATED MONSOONAL MOISTURE. LINGERING SHOWERS WILL REMAIN
POSSIBLE OVER PORTIONS OF ZONES 277/279, ENDING AFTER MIDNIGHT. A
WEAK COLD FRONT WILL MOVE THROUGH EASTERN AND SOUTHERN PORTIONS OF
THE FORECAST AREA THIS AFTERNOON AND TONIGHT. HIGHS THIS AFTERNOON
WILL BE IN THE LOWER TO MIDDLE 80S ACROSS MUCH OF THE AREA, WITH
UPPER 80S IN ZONES 275/282. HUMIDITY WILL BE IN THE UPPER TEENS TO
20S ACROSS MUCH OF THE AREA AND WINDS WILL BE RELATIVELY LIGHT. RH
RECOVERY WILL BE FAIR ACROSS PORTIONS OF THE BIGHORN BASIN,
INCLUDING ZONE 287. ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL REMAIN CONFINED WEST OF THE DIVIDE SATURDAY
AFTERNOON. LOCALLY HEAVY RAIN WILL CONTINUE TO BE A THREAT.
HUMIDITY VALUES WILL BE IN THE UPPER TEENS EAST OF THE DIVIDE
SATURDAY AFTERNOON, HOWEVER, WINDS WILL REMAIN LIGHT ACROSS MUCH
OF THE AREA.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...LAVOIE
LONG TERM...WITTMANN
AVIATION...MCDONALD
FIRE WEATHER...LAVOIE
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