647 FXUS65 KRIW 232004 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 204 PM MDT Fri Apr 23 2021 .SHORT TERM...(This evening through Saturday night) Issued at 1259 PM MDT Fri Apr 23 2021 The short term will see a series of weather systems moving across the forecast area. There is a cold front currently moving across the area with rain and snow showers, mainly across the north. This system will exit the area tonight, leaving slightly cooler temperatures in its wake. The southeast is seeing higher CAPE values, so there is still a chance of an isolated thunderstorm or two this afternoon and evening. This is also staying in agreement with the Storm Prediction Center general area. There will be a brief period of dry weather tonight and Saturday morning as a transitory ridge builds into the region. Saturday afternoon will see the next wave approach western Wyoming, with widespread showers and the chance of convective activity. Rain and snow showers will be mainly across the west, with POPs and QPF staying on the light side. These showers will continue through Sunday across the west, with the help of another wave that will move in. East of the Divide will be a bit breezy, but should stay mainly dry. .LONG TERM...(Sunday through Friday) Issued at 1259 PM MDT Fri Apr 23 2021 The next more potent storm system comes ashore at northern California Sunday, with strong southwesterly flow ahead of it. Energy around the leading edge of the trough along with moisture being brought in on the southwesterly flow will bring a good chance of precipitation to western WY. Since this is a more Pacific-oriented trough, it is not accompanied by a significant cold pool. Thus snowfall will be limited to the higher elevations, with western valleys remaining rain. As the trough slowly moves east across the Rockies, the best energy and moisture from the trough move across the state during the day Monday, bringing rain chances into central WY and more snowfall to the Big Horn Range. The precip chances will continue for central WY into the day Tuesday, before the trough axis passes through, shifting winds aloft from the northwest, helping to push the main energy into the Central Plains. A fast-moving training shortwave will race through Wednesday, mainly to keep skies mostly cloudy and bring some flurries to NW WY. A larger trough will try to build across the western US late week, but may not be strong enough to deflect other minor impulses Friday and into next weekend. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1134 AM MDT Fri Apr 23 2021 Radar continues to note showers drifting across the state, mainly affecting northern and western WY. These showers will continue to produce briefly moderate snow at KCOD and possibly KJAC before moving off to the east this evening. High pressure moving into the state tonight will allow winds to relax at all sites tonight into early Saturday. && .FIRE WEATHER... Issued AT 1259 PM MDT Fri Apr 23 2021 A cold front dropping southward across the state today has brought scattered rain and snow showers, mainly across northern and western Wyoming. Temperatures are staying on the cooler side as well. A thunderstorm or two can't be ruled out in the afternoon. Dry weather should return from tonight into Saturday morning. More showers are possible Saturday afternoon and night but should be confined to western Wyoming. Relative humidity may fall to around 20 percent in the southwest, but should remain above critical levels. A gusty breeze will blow at times today and Saturday. Mixing and smoke dispersal will generally range from fair to poor east of the Divide to good to excellent in the west and south. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Swanson LONG TERM...Straub AVIATION...Straub FIRE WEATHER...Swanson