Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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938 FXUS65 KCYS 302306 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 506 PM MDT Thu May 30 2024 .KEY MESSAGES... - Potential for a late night severe thunderstorm event in the Nebraska Panhandle late this evening into the early morning hours Friday. - Daily chances for precipitation continue into the weekend before turning drier early next week with above average temperatures. - After a weather disturbance produces a slight chance for showers and thunderstorms on Sunday, dry and warm weather will prevail for Monday through Thursday. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 200 PM MDT Thu May 30 2024 Beautiful day ongoing this afternoon with only some upper level clouds being observed across the CWA. Most of Wyoming under the influence of surface high pressure...in between a departing cold front across central Nebraska and an approaching cold front to the northwest. Surface trough extends from north central Colorado...north into the west slopes of the Laramie Range and then northwest into northern Carbon County. Latest mesoscale guidance continuing to forecast a late show tonight for convection...focusing on thunderstorms developing after 06Z. HRRR most aggressive with development and coverage over Cheyenne and Kimball Counties...possibly into the eastern half of Laramie County. MUCAPE values near 1000 to 1500 J/KG over these areas this evening. Did add severe wording into the southern Panhandle for late this evening into early Friday for thunderstorms. Upper shortwave tracks across eastern Montana/northeastern Wyoming Friday afternoon for another rounds of scattered afternoon and evening showers/thunderstorms. Saturday may perhaps be our best chance for severe convection as a dryline develops across southeast Wyoming and pushes eastward into western Nebraska. Depending on the timing of this dryline push...could see supercells developing across the Panhandle Saturday afternoon. Storm Prediction Center already has a Slight Risk area identified for the Panhandle Saturday afternoon. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Issued at 200 PM MDT Thu May 30 2024 Sunday...A progressive and low amplitude shortwave trough aloft is progged to move across the forecast area around peak heating. Although low and mid level moisture looks rather scant, there should be enough moisture for isolated to widely scattered afternoon showers and thunderstorms, mainly east of Interstate 25. A bit warmer than Saturday with 700 mb temperatures near 11 Celsius, yielding maximum temperatures in the upper 70s west of I-25, with 80s east of I-25. Monday...Looks like the warmest day of the week with 700 mb temperatures near 15 Celsius, yielding high temperatures from the mid 80s to mid 90s. Warm temperatures aloft and limited low and mid level moisture will likely keep this day dry. Tuesday...A progressive shortwave trough aloft moves across the northern Rockies, sending a dry cold front across our counties, and dropping high temperatures some 5 to 10 degrees. Wednesday-Thursday...Ridging aloft builds across our forecast area, producing mostly clear conditions and warm temperatures with 700 mb temperatures near 14 Celsius on Wednesday and 17 Celsius on Thursday. Warm temperatures aloft will likely inhibit convective development. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 501 PM MDT Thu May 30 2024 A complex forecast for all terminals east of the Laramie Range due to the threat of overnight thunderstorms. KLAR and KRWL should remain VFR throughout the TAF period, with little concern for nocturnal convection over these sites. High clouds and relatively calm winds expected at these terminals. For remaining terminals (KCYS, KBFF, KCDR, KSNY, KAIA) nocturnal thunderstorm activity will be a concern for all sites. Thunderstorm activity expected to begin just after 06Z and continue through about 13Z. Expect lowering ceilings with these storms, as well as gusty and erratic winds around any storm that develops. Behind the storms, could see ceilings dropping towards the IFR category by sunrise at KCYS and KSNY. Gusty winds initially at KCYS and KBFF before all winds decrease overnight, except when thunderstorms are present. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...GCC LONG TERM...RUBIN AVIATION...AM