Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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154 FXUS65 KCYS 111003 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 403 AM MDT Sat May 11 2024 .KEY MESSAGES... - Trending warmer through the weekend, but remaining unsettled with daily chances for showers and storms. Severe weather is not expected. - Colder with widespread precipitation chances expected across much of SE Wyoming the Nebraska Panhandle on Wednesday. && .SHORT TERM /THROUGH SUNDAY/... Issued at 340 AM MDT Sat May 11 2024 Warmer temperatures and mostly clear skies today will bring a welcome change from the chilly last few days. High temperatures in the 60s to low 70s are expected across southeast Wyoming and western Nebraska. While there are precipitation chances, confidence is low in much accumulating rainfall as conditions will be mostly dry across the High Plains. Any thunderstorms that do develop will likely be relatively weak as HiRes guidance is only showing CAPE values 100-300 J/kg and bulk shear 10-20 knots. The best chances for thunderstorm development is expected to be along and south of the Interstate-80 corridor. Sunday brings similar conditions to Saturday with high temperatures just a few degrees warmer. However, as the low pressure system currently positioned near the Four Corners region drifts east, there is an additional push of low- level moisture into far southeast Wyoming and the southern Nebraska panhandle that will aid in the precipitation chances. Any thunderstorms that do develop are still expected to be weak, mainly tied to higher terrain and areas along and south of the Interstate-80 corridor. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 340 AM MDT Sat May 11 2024 The long term forecast continues to show chances for isolated afternoon thunderstorms, with better chances for more scattered to widespread precipitation chances Tuesday and Wednesday. Temperatures will continue to be warm Monday and Tuesday with temperatures likely remaining in the upper 60s to low 70s. By midweek, we are tracking a cold storm system that will push a potent cold front through the region that will increase precipitation chances across the region as well as bring cooler temperatures. We should trend toward drier conditions with gradually warming temperatures toward the end of the week. By Sunday night, the slow churning upper level low pressure system will be pushing east across western Nebraska/Kansas with the bulk of the wrap around moisture and precipitation should be coming to an end from west to east as the evening progresses. With the position of the low pressure system we could see some easterly winds develop that may keep some low clouds and drizzle in place across the typical upslope regions during the early morning hours on Monday. Monday looks be quiet day across the region as a weak upper level ridge axis moves but this too will quickly move east of the region throughout the day on Monday. We will see the benefits of some warmer 700mb temperatures which will allow for temperatures to jump into the 70s across much of SE Wyoming and the Nebraska Panhandle. Heading into Tuesday models have shifted a bit on the overall pattern across the region. Models are now showing a deeper trough developing across western Montanta which will have a downstream transition to to a SW flow across much of Wyoming, this deeper trough also means the ridge will hold in place longer before getting ejected to the east. The evolution of this trough becomes quite messy with models initially pushing this feature in as a positively tilted trough before pinching off a weak closed low over central Utah with strong shortwave pushing out of eastern Montanta on Wednesday. This secondary shortwave looks to push a cold front north to south across the region bringing with it colder temperatures and more widespread precipitation chances with the potential for some high elevation mountain snow showers. This system looks to move through the region quickly and it is looking like Wednesday may be the only day of cold, wet weather as in the wake of this passing shortwave, a ridge axis begins to nose eastward from the western CONUS into our region that should dry the region out and bring back some warmer temperatures. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 340 AM MDT Sat May 11 2024 VFR conditions expected to persist through the 12Z TAF period with mostly clear skies and generally light winds overnight. Saturday afternoon southeast Wyoming may see wind gusts 20 to 25 knots, weakening near sunset. In addition, there`s a chance for an isolated shower/thunderstorm near KCYS, KLAR, and KSNY between 18Z and 03Z, but confidence is low in direct TSRA at the terminals. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...LEG LONG TERM...AW AVIATION...LEG