022 FXUS65 KRIW 050345 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 945 PM MDT Wed Jun 4 2025 .KEY MESSAGES... - Chances (50 to 60%) of showers during the evening and overnight hours, especially east of the Divide. - Afternoon shower and thunderstorm chances (15 to 25%) continue Thursday with lesser chances Friday. - Warming trend accelerates towards Friday, with 80s returning by Saturday and continuing warming through the early part of next week. && .UPDATE... Issued at 133 PM MDT Wed Jun 4 2025 A wave of showers pushed through portions of central WY during the morning, and exited the region by around 1100L. Partially thanks to increased cloud cover and cooler temps behind that wave, and also the result of a meso-high over central WY, afternoon convection will generally be suppressed. A few showers and storms will be possible (10 to 20% chances), mainly along the mountains, but any storms will be weak with little forcing to sustain them. By the early evening, a shortwave pushing out of SW WY will bring better chances for showers to the region. Hi-res guidance remains in agreement that this wave will push into eastern Sweetwater County around 1700L. As it crosses the Divide a few hours later, the wave will start to tap into some additional moisture, with PWATs east of the Divide increasing through the evening to around 0.5 in. Have ticked up QPF amounts through the evening and overnight to reflect this. Similarly to today, showers will push east out of the CWA by mid- to late-morning on Thursday. CAMs continue to develop convection Thursday afternoon, again primarily along and east of the Divide, with terrain looking to play a key role in initiating lift for those storms. Models have begun to push the upper level ridge into the region more quickly than previous runs, which should limit convection more-so on Friday. Friday will also see temperatures that are around 10 degrees warmer than Thursday as the warming trend accelerates with the incoming high pressure. && .DISCUSSION... Issued at 1254 AM MDT Wed Jun 4 2025 Multiple shortwaves moving over Wyoming is the weather story for the next couple days. Showers continue to track eastwards across the Bighorn Basin and into Johnson County early this morning. This continues through the morning hours, with most of this activity done by early afternoon. Rain chances then turn to afternoon convection as a shortwave passes through. Not much change from the previous forecast with respect to where showers and storms are most likely. High-resolution models continue to keep a majority of showers/storms over the mountains, namely the Absaroka, Wind River, and Bighorn Ranges. Some of this convection could move off the higher terrain, into the nearby foothills and lower elevations. Mid-to-late afternoon, there could also be some showers and storms over Sweetwater County as well, as another shortwave moves in. After midnight, precipitation chances (30% to 70%) will be along and east of the Continental Divide, which then continues through Thursday morning. Shower and thunderstorm chances continue for Thursday, mainly along and east of the Divide, though there will be some west of the Divide too. Gusty winds over 30 mph would be the main hazard with Thursday storms. Similar story for Friday as the northwest flow aloft continues to push shortwaves through. Temperatures also warm through the end of the workweek. The eastern extent of a high pressure system pushes into the area for Saturday. This should limit precipitation chances, but there still may be a few over the mountains. However, overall it will be warm and dry, with highs in the upper 70s to upper 80s. Even warmer for Sunday as high pressure shifts east. Current long range models would suggest Monday or Tuesday being the warmest with this high pressure, before the axis moves to our east. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 944 PM MDT Wed Jun 4 2025 To begin the TAF period a weather system is sliding across the area with rain pushing through central Wyoming. Expect -RA at KRIW, KLND, KWRL, and KCPR tonight, with rain pushing east out of the area Thursday morning. KCPR will drop to MVFR/IFR due to low CIGS and decreased VIS from rain. At other terminals with rain tonight the rain should be light enough that VIS remains VFR and CIGS should not drop to MVFR. Isolated rain showers and thunderstorms will develop Thursday afternoon, but again should be mostly limited to mountains. Another weather system will bring more scattered rain showers through central Wyoming Thursday evening into Thursday night. Expect frequent mountain obscuration around Casper Mountain and the Bighorn Mountains tonight into Thursday morning. Wind will be around 10-15 knots at KRIW and KCPR this evening into tonight from the northeast/east as the weather system slides through the area. It will also be a bit breezy from the northwest at KBPI, KPNA, and KRKS Thursday afternoon. At KRKS the wind will shift northeasterly once again Thursday evening as the next weather system slides into the area. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hensley DISCUSSION...Wittmann AVIATION...Rowe