Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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354 FXUS65 KCYS 252043 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 243 PM MDT Sat May 25 2024 .KEY MESSAGES... - Mountain snow showers will accumulate in the Snowy and Sierra Madre tonight and early Sunday, with total possible accumulations of 2 to 6 inches above elevations of 9500 feet. Scattered rain showers and an isolated strong to potentially severe thunderstorm can`t be ruled out east of the Laramie Range and Nebraska Panhandle today. - Strong winds are possible in the wind prone and gap areas of southeast Wyoming early Sunday morning through the mid- afternoon. Please see the latest High Wind Watch Statement for further details. - A much warmer, milder week ahead as an upper-level ridge overtakes the region. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 150 PM MDT Sat May 25 2024 Radar analysis shows a band of showers with a few embedded thunderstorm cores stretching from Cheyenne to Scottsbluff with this whole area moving off to the northeast. A few isolated thunderstorm cores are trying to organize but with the limited instability available, they are remaining on the weaker side. Still could see pea sized hail out of those cores but outside of that, impacts a limited. Temperatures have cooled off where rain has been observed dropping much of SE Wyoming down into the 50s. With the passing shortwave aloft, we can expect additional development of showers for the lower elevations through the rest of the afternoon. Heading into the overnight hours we will see the development of that high elevation mountain snow. Some of the highest peaks over the Sierra Madre and Snowy`s could see 5-7" of snow. This shortwave will move to the east of the Front Range by tomorrow morning allow for some subsidence to advect in its wake. Coinciding with this subsidence will be a band of 50kt 700mb winds arriving with the next shortwave trough moving west to east through Wyoming. In-house model guidance continues to show high probabilities for high winds primarily for the Arlington wind prone area. The setup does favor areas along the south Laramie Range Foothills and Summit to see some periods of high winds as well. The current High Wind Watch seems appropriates it captures the current forecast trends. With a more potent shortwave trough passing aloft and some residual low level moisture in place across SE Wyoming and the Nebraska Panhandle, we could see more showers and thunderstorms develop Sunday afternoon. These storms will encounter a better environment as daytime heating and limited cloud over should allow for some destabilization to occur with the best corridor of CAPE values being shown across the northern Nebraska Panhandle. A few strong storms will be possible and we can`t rule out a storm or two becoming severe. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 150 PM MDT Sat May 25 2024 Few changes made to the long term forecast, with Memorial Day still looking dry for those with outdoor plans. Likely a bit breezy across the area as a shortwave passes to our northeast, but temperatures will be average for late May with afternoon highs in the upper 60s and 70s. Headed into the remainder of the work week, an upper-level ridge will build over the Rockies Tuesday into Wednesday, sandwiched between two troughs. This will lead to warmer, above average temperatures during this time frame as 700 mb temperatures climb into the +10C to +14C range. By Wednesday, highs will be in the upper 70s and low 80s. Ridging will lead to dry conditions on Tuesday, but an embedded disturbance moving through the ridge on Wednesday could spark some afternoon and evening convection. Per GFS soundings for Wednesday afternoon, there is the potential for severe storms. Soundings from across the Nebraska panhandle do show surface CAPE values approaching 2000 J/kg. MUCAPE values are also approaching 2000 J/kg which will primarily lead to a large hail threat. Aside from hail, will also have to keep an eye on PWs as these soundings are encroaching on 1 inch PWs. Cloud layer winds are also on the slower side which could lead to the potential for minor flooding. After Wednesday, daily precipitation chances look possible through the end of the work week. Although the GFS and ECMWF diverge by Thursday and Friday, both still have afternoon thunderstorm chances. The biggest difference between the two is temperature. The GFS sends a trough north of the CWA, while the ECMWF dives the trough further south with a strong cold front moving across the CWA. If the ECMWF solution comes true, expect much cooler, below average temperatures headed into the start of the weekend. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1150 AM MDT Sat May 25 2024 Main aviation concern today will be scattered showers and thunderstorms this afternoon and evening. Storms could contain hail and gusty, erratic winds. Some visibility reductions could be possible in moderate rain. Scattered showers will continue later tonight. Low CIGs could be possible at KRWL and KLAR tonight as a shortwave passes over the region. Low CIGs will clear by sunrise. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...High Wind Watch from late tonight through Sunday afternoon for WYZ106-110-116-117. NE...None. && $$ SHORT TERM...AW LONG TERM...SF AVIATION...SF