Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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343 FXUS65 KCYS 212050 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 250 PM MDT Sun Apr 21 2024 .KEY MESSAGES... - Elevated to high winds possible for areas west of the Laramie Range Monday afternoon. - Relatively mild temperatures are expected for Wednesday and Thursday along with a chance of late day showers and thunderstorms. - Cooler and unsettled weather is likely for Friday and the weekend. && .SHORT TERM /THROUGH TUESDAY/... Issued at 220 PM MDT Sun Apr 21 2024 Current Visible Satellite loop shows mostly sunny skies across southeast Wyoming and western Nebraska after 3 straight days of overcast skies for a good portion of the area late last week. Shortwave upper level ridge axis has pushed east across the state with 700mb temperatures climbing over 0c and towards 5c late this afternoon. Surface temperatures have responded in most locations with readings in the 50s to mid 60s. However, a persistent southerly wind has kept the west to east facing ridges in the mid to upper 40s for most of the day. Expect winds to gradually shift into the southwest and west later today, but locations such as Cheyenne, Kimball, Harrison, Lusk, and Sidney may struggle to reach the upper 50s to low 60s this afternoon. Not as cold tonight with increasing high clouds and increase winds ahead of the next cold front, with lows mainly in the 30s to near 40. Main forecast concern will likely be winds for Monday, but impacts should be confined to southeast Wyoming with minor impacts at best. All models show 700mb winds increasing between 45 to 55 knots by early Monday morning and remaining elevated through most of the day. Pacific cold front should be quick to push into the eastern plains through the afternoon, so expect the warmest temperatures to be across southern Wyoming and the southern Nebraska Panhandle where highs in the 60s to around 70 degrees are expected...along and south of the I-80 corridor. With the lack of a west to east pressure gradient, due to the progressive nature of the front, low level gradients are lacking for a widespread wind event. However, will have to watch some of the wind prone areas for gusts of 55 to 60 MPH early Monday morning through late Monday afternoon. Some of the zones near the wind prone areas may receive some of these higher gusts due to mountain wave activity, but confidence with timing and location(s) are low. Boundary layer subsidence isn`t all that impressive, but it does peak in the late morning/early afternoon on Monday in the lee of the Snowy Range and across the foothills of the southern Laramie Range. Expect these locations to have the best chance at seeing wind gusts around 55 to 60 MPH. Other than winds, not much else to discuss for the weather early this week. Tuesday will be slightly cooler after FROPA with highs in the mid 50s to mid 60s, seasonable for this time of the year. Increased POP across southeast Wyoming later on Tuesday since the remnants of the cold front will provide low level convergence along and west of the Laramie Range with easterly winds along/east of I-25, and winds shifting into the northwest along and west of the front. Expect showers and some rumbles of thunder to return to the forecast area as early as Tuesday evening. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 135 PM MDT Sun Apr 21 2024 Wednesday...Ridging aloft builds across the region which will produce a decent warming trend as 700 mb temperatures rise to near 5 Celsius, yielding maximum temperatures in the upper 60s and lower 70s. Looks like there may be enough low and mid level moisture combined with easterly upslope winds to spark isolated to scattered afternoon showers and thunderstorms. Thursday...The next progressive shortwave trough aloft moves across Wyoming and Colorado, helping to produce scattered afternoon and evening showers and thunderstorms. Continued relatively mild based on the projected 700 mb temperatures. Friday...In the wake of the passing shortwave trough aloft and its associated cold front, cooler and unsettled weather expected with adequate low and mid level moisture. Looks like scattered to numerous showers, along with isolated thunderstorms. Saturday...Cool and unsettled weather looks to continue as another potent shortwave trough aloft approaches Wyoming near peak heating. With abundant low and mid level moisture, combined with decent upslope and low level convergence and dynamic lift, we anticipate scattered to numerous afternoon and evening showers, along with scattered thunderstorms. Relatively cool temperatures due to all the cloud and precipitation coverage. Sunday...Although the shortwave trough aloft will be located in the Dakotas, it looks like there will be adequate low and mid level moisture over our counties along with cyclonic curvature aloft, to produce scattered afternoon and evening showers, along with isolated thunderstorms. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1144 AM MDT Sun Apr 21 2024 Northwest flow aloft will become west overnight and strengthen. Clear skies will prevail this afternoon, then scattered to broken clouds near 15000 feet will spread across the terminals tonight and Monday. Winds will gust to 26 knots at all terminals except Scottsbluff until 02Z, then will gust to 30 knots at Rawlins and Laramie after 15Z Monday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...TJT LONG TERM...RUBIN AVIATION...RUBIN