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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