textproduct: Cheyenne

KEY MESSAGES

- Widely scattered showers and isolated thunderstorms are expected this afternoon and evening, and may produce gusty and erratic winds.

- An powerful cold front arriving Monday will bring a chance for showers and thunderstorms, changing over to snow Monday night and continuing into Wednesday morning.

- Accumulating snowfall is likely (70% chance) over 6000 feet in elevation, with significant snowfall possible in the Snowy Range, southern Laramie Range, and their adjacent foothills.

- Drier, warmer, and windier weather returns to the area for the second half of the work week.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 216 PM MDT Sun May 3 2026

Now: Some storms are popping up across Campbell county and are slowly dipping south into Converse and Niobrara county. These storms are currently producing lightning with some rain possibly hitting the ground but would still need to watch out for any fires started by dry lightning. There are also a couple showers that is producing mostly virga with a couple spits of rain in Central Laramie County and crossing the Colorado border. The HREF shows some modest CAPE that these storms could utilize along the Northern border of our forecast area.

Monday and Tuesday: A cold front will push through Monday morning to kick off some rain showers in the early afternoon. The surface cold front is expected to pass through during the day. This may reach Douglas to Chadron by 7AM or so, stunting high temperatures there for the day. The front should reach the I-80 corridor by midday. As a result, expect most areas to see a morning or early afternoon high temperature, with gradual cooling through the afternoon hours. After sunset, temperatures will begin to rapidly cool. The surface front will slow down as it pushes up against the higher terrain of southern Wyoming and northern Colorado, leading to frontogenesis. Forecast soundings along the I- 80 corridor Monday afternoon look nearly saturated with fairly steep lapse rates in place. SBCAPE could locally exceed 1000 J/kg. Strong forcing provided by the frontogenesis and moderate overrunning flow should kick off numerous showers and scattered thunderstorms around midday Monday, mostly along the I-80 corridor. A few stronger storms capable of producing hail and gusty winds cannot be ruled out. By the evening into the overnight hours the rain will transition to snow across the southern half of the forecast area. The mountains will likely transition into snow the quickest due to the higher elevation. The lower elevations are expected to switch a lot slower leading to more of a rain/snow mix through the overnight period. Majority of model guidance depicts strong a strong band of FGEN with some isentropic lift to increase the precipitation rates and lead to greater accumulations. The LREF shows a 25/75th percentile of 3 to 8 inches of snow for Central Laramie county and between 5 to 11 inches for the foothills/summit area. Due to the favorable upslope flow the Snowy range could see between 13 to 18 inches depending on elevation. The models also show the band of FGEN to be pretty progressive through our area, however the mountains may hinder it some leading to possibly higher amounts on the mountain. The Sierra Madres are expected to be mostly shadowed by the Snowies this event so up to 6 inches is expected for that range. Since Laramie also sits in bowl, there's also some potentially shadowing for the town as well leading to lower accumulations than the rest of the area. Accumulations will also depend on the timing, as snow falling during the day will be much less likely to stick and accumulating thanks to the very strong early May sun. We will therefore wait a little longer for confidence to improve before including lower elevation zones in any winter weather headlines. However, if this plays out like the models are anticipating then an Advisory or a winter storm warning may be needed for the lower elevations in the mountains and also possibly for Laramie county as well.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Issued at 410 AM MDT Sun May 3 2026

Strong ridging will try to build back into the western US immediately after this storm system. While Wednesday will still feature temperatures well below average for this time of year, expect warmth to recover quickly. Highs around 5F above average can be expected on Thursday, climbing closer to 10F above average by Saturday. Northwest flow will kick up quickly behind the departing trough axis on Wednesday, and lead to breezy to windy conditions. The strongest winds are anticipated on Thursday, when the southeast Wyoming wind prone areas continue to have a 20 to 40% chance for high winds. Both Thursday and Friday will feature isolated to widely scattered PM showers and perhaps a few thunderstorms, but rainfall expectations are limited at best. Precipitation potential will tick up over the weekend a progressive upper level low approaches the area from the northwest. The details concerning this system remain highly uncertain at this lead time.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 521 PM MDT Sun May 3 2026

Isolated to scattered showers and storms are ongoing across portions of the area, namely northern portions of the Nebraska Panhandle. Gusty and erratic winds are possible in and around any showers and storms across the area. Showers will start to taper off over the next 1 to 2 hours, with most locations not seeing precipitation after 02Z. Light and variable winds return overnight before gusty winds pick up behind a passing cold front tomorrow afternoon. Precipitation chances pick up significantly after the end of the 00Z TAF period.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Winter Storm Watch from Monday evening through Wednesday morning for WYZ110-114-116-117. Red Flag Warning until 8 PM MDT this evening for WYZ430-431. NE...None.