Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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511 FXUS65 KRIW 131118 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 518 AM MDT Mon May 13 2024 .KEY MESSAGES... - Fast moving pattern bring multiple systems through the region this week. Multiple chances for showers and thunderstorms through midweek. - Temperatures remain near normal across the state in the 60s. - Ridging brings warmer conditions for the latter half of the week, but daily showers will remain a threat for higher elevations. && .DISCUSSION... Issued at 212 AM MDT Mon May 13 2024 Weather pattern will remain a little more active starting this week, as westerly flow brings multiple rounds of spring rainfall to western WY. First round arrives today On the leading edge of a shortwave trough sweeping in from the northwest. This first wave will focus most shower activity on the northern third of the state and the western mountains, where the best probability of measurable rainfall occurs. Some showers may reach into Fremont and Natrona Counties this afternoon, but overall activity there will be brief and light still. Next shortwave follows quickly on its heels for Tuesday, which is currently more amplified than the Monday wave. This will bring some added lift and shear across the northern 2/3 of the state, resulting in more numerous showers and thunderstorms. With dry air remaining at the sfc, inverted-v profiles will bring the threat for gusty winds with any of these thunderstorms, starting Tuesday afternoon across the Bighorn Basin and the western mountain ranges, then shifting southeast across Fremont, Natrona, and Johnson Counties Tuesday evening. Lower elevations of Lincoln, Sublette, and Sweetwater Counties have a lower chance for showers, but the gusty wind threat remains there as well. Shortwave trough number three follows right behind just in time for Wednesday afternoon. Models are differing enough on placement of this trough that rainfall forecast confidence begins to decrease at this point. The trough likely will remain farther west, taking most midlevel energy with it. But there`s enough moisture still in place east of the divide for the shower possibility to continue during peak heating Wednesday afternoon. Beyond this for the latter half of the week, models are all over the place on trying to build some weak ridging across the Four Corners. While there would be a lack of shortwaves across western WY Thursday through Saturday, enough moisture and daytime heating would still bring daytime showers and thunderstorms along the higher elevations of western and northern WY each afternoon. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 514 AM MDT Mon May 13 2024 Largely VFR conditions will prevail through Monday night. However, local MVFR conditions will be possible in any shower or thunderstorm. We have added VCSH to KCOD, KWRL and KCPR given morning radar trends. Convection will be increased in coverage Monday afternoon, though still focused on the northern half of Wyoming. KCOD, KJAC, and KWRL will have the best chance of terminal impacts, though confidence remains low on specific timing. We also added VCSH to KBPI and KPNA given radar trends. Otherwise, KBPI, KPNA, and KRKS will see a breezy afternoon. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Straub AVIATION...Hattings