271
FXUS65 KRIW 231600
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1000 AM MDT SUN AUG 23 2026
KEY MESSAGES
- MONSOONAL MOISTURE CONTINUES THIS AFTERNOON AND EVENING BUT
NOT AS WIDELY SCATTERED AS SATURDAY WITH LOCALIZED FLOODING
POSSIBLE IN THE STRONGEST STORMS.
- STRONG TO SEVERE STORMS POSSIBLE (30-40%) LOOKING MORE LIKE
THE EVENING TIME FRAME AFTER 6PM WITH A LINE OF STORMS FROM
IDAHO CAPABLE OF PRODUCING DAMAGING WINDS UP TO 60 MPH.
- MONSOONAL MOISTURE WILL LINGER MUCH OF THE WEEK, WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS EACH DAY. TEMPERATURES WILL BE
CLOSER TO SEASONABLE FOR THIS TIME OF YEAR NEARING THE END OF
AUGUST.
DISCUSSION
ISSUED AT 226 AM MDT SUN AUG 23 2026
IT WAS A TYPICAL MONSOON DAY YESTERDAY, WITH SOME AREAS, MAINLY IN
SOUTHWEST AND IN JOHNSON AND NATRONA COUNTIES GETTING A LOT OF RAIN,
CAUSING SOME LOCAL FLOODING. OTHER AREAS SAW NOTHING. AND WE
CONTINUE TO HAVE SOME SHOWERS AND EMBEDDED THUNDER AROUND LATE
TONIGHT, ALTHOUGH INTENSITY IS SIGNIFICANTLY LESS. AND THESE WILL
CONTINUE THROUGH THE NIGHT, GRADUALLY BECOMING WEAKER AND LESS
NUMEROUS.
WE WILL HAVE ANOTHER ROUND OF SHOWERS AND STORMS TODAY. THERE ARE
SOME DIFFERENCES. FOR ONE, PRECIPITABLE WATER VALUES ARE LESS TODAY
BY ABOUT 20 PERCENT IN MOST LOCATIONS. THIS SHOULD BRING LESS
COVERAGE AND SOMEWHAT LESSER RAINFALL RATES. THE OTHER DIFFERENCE IS
THAT THERE WILL BE MORE STEERING FLOW TODAY, GENERALLY ABOUT 10 TO
15 KNOTS AT 700 MILLIBARS AND 25 TO 35 KNOTS AT 500 MILLIBARS. SO
STORMS SHOULD HAVE MORE MOVEMENT. THIS SHOULD DECREASE THE CHANCE OF
FLOODING SOMEWHAT. WE STILL HAVE AN EXCESSIVE RAINFALL OUTLOOK
ACROSS MOST ARES WEST OF THE DIVIDE THOUGH, SO THE THREAT IS
STILL THERE. THERE IS ALSO THE RISK OF STRONG TO SEVERE
THUNDERSTORMS. MOST OF THE AREA IS UNDER A MARGINAL RISK OF
SEVERE WEATHER TODAY. THERE COULD BE SOME SMALL HAIL, BUT THIS
NOT THE MAIN RISK. THE MAIN RISK LOOKS TO BE STRONG WIND GUSTS.
ROUGHLY NORTH AND WEST OF A BUFFALO TO RIVERTON TO LYMAN LINE
HAS A CONDITIONAL 1 OUTLOOK FOR WIND, OR POSSIBLE CONVECTIVE
WIND GUSTS TO 75 MPH. SOUNDINGS DO SHOW SOME INVERTED V
PROFILES, ESPECIALLY ACROSS NORTHWESTERN WYOMING WHERE THE
SURFACE WILL BE DRIER, WITH LOW AND MID LEVEL LAPSE RATES CLOSE
TO 9 C/KM. THIS COULD LEAD TO SOME STRONG DOWNBURST WINDS LATER
TODAY. AGAIN, THE BEST CHANCE WOULD BE ACROSS THE NORTHWEST BUT
MOST AREAS WILL HAVE A CHANCE. AND, LIKE PREVIOUS NIGHTS, MOST
CONVECTION SHOULD END AFTER SUNSET BUT A FEW SHOWERS AND STORMS
WILL LIKELY LINGER THROUGH THE NIGHT. AS FOR TEMPERATURES, THEY
SHOULD BE A FEW DEGREES WARMER THAN YESTERDAY WITH MORE SUNSHINE
EXPECTED.
THE REST OF THE WEEK LOOKS LIKE MORE OF THE SAME AS THE ANNOYING
MONSOONAL MOISTURE WILL HANG AROUND THE AREA THROUGH AT LEAST
THURSDAY AND POSSIBLY INTO FRIDAY AS WELL. THE MODELS CONTINUE TO
HAVE DIFFERENT IDEAS ON WHICH DAY WILL BE MORE ACTIVE WITH NO REAL
WELL DEFINED SHORTWAVES WITH CHANGES FROM DAY TO DAY. PRECIPITABLE
WATER GENERALLY AVERAGE ABOUT 125 TO 150 PERCENT OF NORMAL THROUGH
THE PERIOD THOUGH. SO, AT THIS POINT WE WENT WITH A GENERIC SOLUTION
OF MAINLY DIURNAL SHOWERS AND STORMS EACH AFTERNOON. TEMPERATURES
SHOULD REMAIN FAIRLY SIMILAR THROUGH THE PERIOD, NOT VERY HOT BUT
AVERAGING AROUND 4 TO 8 DEGREES ABOVE NORMAL ON AVERAGE, WITH THE
POSSIBILITY OF A COOLER DAY IF THERE IS MORE CLOUD COVER THAN
EXPECTED. DRIER AIR MAY THEN WORK IN FOR NEXT WEEKEND AND BRING A
RETURN TO DRIER WEATHER BUT UNCERTAINTY REMAINS HIGH ON THE EXACT
TIMING. SO, ALL IN ALL, IT CONTINUES TO LOOK LIKE MORE OF THE SAME
AS THE SUMMER OF THE MONSOON LIVES ON IN WESTERN AND CENTRAL
WYOMING.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 416 AM MDT SUN AUG 23 2026
A FEW SHOWERS WILL LINGER EARLY THIS MORNING IN VICINITY OF
KCPR AND KRKS UNTIL AROUND 13Z TO 14Z, FOLLOWED BY A CLEARING
SKY. TODAY WILL BE ANOTHER DAY OF SCATTERED SHOWERS AND
THUNDERSTORMS, WITH THE BEST CHANCE OF A SHOWER OR THUNDERSTORM
AFTER 20Z UNTIL AROUND 04Z MONDAY. THE BEST CHANCE IS ACROSS THE
NORTHWESTERN TERMINALS, ESPECIALLY IN VICINITY OF KJAC WHICH HAS
THE HIGHEST CHANCE. MOST OTHER TERMINALS HAVE AROUND A 20 TO 25
PERCENT CHANCE, AND PROB30 GROUPS WERE INCLUDED FOR THOSE. THE
SMALLEST CHANCE IS AT KCPR, WITH THE CHANCE LESS THAN 20 PERCENT
SO WE LEFT THUNDER OUT OF THE FORECAST FOR NOW. HOWEVER,
CONFIDENCE IS LOW IN TIMING INDIVIDUAL SHOWERS AND STORMS. A
GUSTY WIND WILL INCREASE IN VICINITY OF KRKS AND KCPR THIS
AFTERNOON, WITH GUSTS OF 20 TO 25 KNOTS.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC
FOR THE LATEST INFORMATION ON SMOKE, ICING AND TURBULENCE
FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HATTINGS
AVIATION...HATTINGS
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