059 FXUS65 KRIW 101108 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 508 AM MDT Thu Jul 10 2025 .KEY MESSAGES... - Widely scattered rain showers will continue over the southern half of the forecast area this morning. Isolated showers will be possible across areas east of the Divide this afternoon. - A cold front will move over areas east of the Divide early Friday morning, becoming stationary along the Divide. Highs in the 70s will be widespread in these areas as a result. - Dry conditions and a warming trend over the weekend with elevated fire weather conditions returning by Sunday. && .DISCUSSION... Issued at 120 AM MDT Thu Jul 10 2025 Weak showers will continue over the southern half of the CWA this morning, as a remnant low approaches the area from southern ID. Any rainfall amounts will be very low, a trace to 0.02", along with very isolated lightning strikes. Showers will remain isolated over this area through the rest of the morning after sunrise, as the low reaches far southern WY. The focus for precipitation will shift east of the Divide this afternoon, as the low exits over eastern portions of the state. Wind gusts of 50 to 55 mph will be the main threat, along with some lightning. Instability will be limited, as CAPE values will range between 200-500 J/kg. Temperatures will be about 10 degrees cooler across the CWA as a result of the passage of this remnant low. Fire weather conditions will remain elevated as well, with critical RH values returning to portions of the Wind River and Bighorn Basins and Sweetwater County. A cold front will reach northern WY sometime between 06Z and 12Z Friday, quickly progressing southward and reaching the Divide by 15Z. Any precipitation looks to be confined to northern portions through much of the day Friday, but could progress into the Wind River Basin in the afternoon. Any thunderstorms look to occur along the Divide, due to the front. Highs in the 70s east of the Divide remains in the forecast, while areas west of the Divide stay in the low to middle 80s. Locations in northern Johnson County may not reach 70 degrees, which would be a 30 degree dip from yesterday. Dry conditions then return for the weekend, with a somewhat northwest flow pattern aloft. This will lead to seasonal temperatures on Saturday and highs in the 90s return for areas east of the Divide on Sunday. Showers and thunderstorms could be possible Monday and Tuesday, as another trough drops south from British Columbia and bringing the trough/cold front through Tuesday night. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 449 AM MDT Thu Jul 10 2025 VFR conditions expected throughout the period at all TAF sites. Some ongoing rain showers/ thunderstorms continue west of the Divide to include KRKS through the morning at 13Z . Increasing winds up to 18kts at most locations, highest at KPNA up to 22 knots after 16Z-18Z through peak heating until sunset after 01Z-02Z with radiational cooling. The chance of thunderstorms (around a 1 in 5 up to a 1 in 4 chance) will be found in and near most mountain ranges, especially East of the Divide. We have added PROB30 groups for KRIW, KCPR, KLND and KCOD for this afternoon and early this evening as a result. Any shower or thunderstorm could bring brief MVFR conditions, but enough confidence to include in the TAFs at this time. Additional showers may approach the northern Wyoming sites late Thursday night but most should hold off until after 12Z Friday. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence && .FIRE WEATHER... Issued at 120 AM MDT Thu Jul 10 2025 Elevated fire weather conditions will return for one more day today, with critical RH values occurring along eastern portions of the Bighorn Basin, the Wind River Basin and Sweetwater County. Winds will not be a contributing factor, however gusty outflows could occur (20% chance) from showers over the Absaroka, Bighorn and Wind River Mountains this afternoon. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...LaVoie AVIATION...Hattings FIRE WEATHER...Dziewaltowski