Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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600 FXUS65 KRIW 012206 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 406 PM MDT Wed May 1 2024 .KEY MESSAGES... - Afternoon scattered showers and weak thunderstorms are in the forecast daily through Friday. Light mountain snow accumulations are also possible over the next 48 hours. - Elevated fire weather conditions exist this afternoon for Sweetwater and Natrona counties, due to a combination of breezy winds and a dry air mass. - This weekend will be warm and dry east of the Divide, with cooler and wetter conditions for western Wyoming mountains and valleys. && .DISCUSSION... Issued at 250 PM MDT Wed May 1 2024 A longwave trough resides over the Intermountain West this afternoon, with an approaching embedded shortwave. The cool air aloft will encourage scattered shower development, but accumulations from the short-lived showers will be minimal. This afternoon and evening will also feature breezy winds in the Sweetwater to Natrona county wind corridor as the shortwave trough tightens the surface pressure gradient. When combined with the relatively dry air mass, elevated fire weather conditions will exist through sunset. Thursday and Friday feature much of the same weather, with temperatures about 5 degrees below seasonal averages, and scattered afternoon showers. Accumulations will again be minimal for lower elevations. Winds will be lighter these days, so fire weather concerns are not as high. On Saturday, a brief ridge moves through the Rockies, leading to a quick warm up to about 10 degrees above seasonal normals. No precipitation is expected, and winds are not overly breezy, making conditions favorable for many outdoor spring activities. On Sunday, a deep trough begins to push into the western Wyoming mountains. This will bring a return of showers for locations west of the Divide, but those in the basins east of the Divide will enjoy a very mild day, with temperatures 15 or so degrees above average. On Sunday night into Monday, the weather system associated with this trough will move across the state, bringing a noticable cooldown, as well as more numerous showers and measurable precipitation for many. Western Wyoming valleys could see light snow during the overnight timeframe, but this would likely melt quickly after sunrise Monday given high temperatures in the 40s. In the wake of this system, conditions moderate to near seasonal averages by mid-week. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 342 PM MDT Wed May 1 2024 The best chances for precipitation should be coming to an end the first few hours of the TAF period, mainly for northern Wyoming sites. There is about a 15% chance for showers impacting KCPR, KLND, and KRIW through about 06Z, slightly longer at KCPR. Winds also decrease after sunset for most locations, with gusty winds ending by around 05Z. A northwest drainage wind is possible longer at KRIW. Winds then increase again Thursday, with gusts generally 20 to 30 knots for many sites. Showers are again possible for the afternoon, occurring in similar locations to what occurred Wednesday. 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. && $$ DISCUSSION...VandenBoogart AVIATION...Lowe