textproduct: Cheyenne

KEY MESSAGES

- Cooler, wetter weather will continue tonight and Friday.

- A strong cold front moves through tonight into the early morning hours Friday, resulting in high winds across portions of southeast Wyoming.

- Warmer, drier weather returns this weekend, with fire concerns increasing for the start of the week.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 125 PM MDT Thu Apr 2 2026

Tonight...A progressive and potent upper trough moves from western Wyoming this evening to eastern Wyoming by dawn Friday, with its associated strong cold front sweeping west to east across our forecast area this evening across southeast Wyoming and after midnight across the Nebraska panhandle. With the projected track of the upper trough and the expected 50+ knot winds in the low levels, combined with our Craig to Casper 850 and 700 mb height differences ramping up over 60 meters, we continue to anticipate strong winds increasing across southeast Wyoming this evening, with the current High Wind Warnings for Arlington, Bordeaux and the I-80 Summit and foothills cranking up this evening. Winds still not boosting up a lot across Carbon County, and thus will continue with the High Wind Watch there through this afternoon. Low level gradients and winds as well as the strong cold air advection will help strong winds to spread into Central Laramie County and Cheyenne after mid evening and thus the timing of the High Wind Warning looks decent there.

With adequate low and mid level moisture combined with 500-300 mb and 700-500 mb quasigeostrophic lift and orographics, heavy snow expected to ramp up across our Snowy and Sierra Madre Ranges this evening and with expected snowfall totals, the inherited Winter Storm Warning looks on track.

Friday...A blustery and cold day expected as the upper trough moves from eastern Wyoming to central South Dakota by evening, with strong low level northwest winds and cold air advection, as well as the 850 and 700 mb Craig to Casper height gradients suggesting strong winds continuing through the afternoon for Arlington, Bordeaux, the I-80 Summit and foothills and central Laramie County and Cheyenne. Orographic snows continue for our Snowy and Sierra Madre Ranges and the northern Laramie Range and nearby lower elevations, as well as cyclonic flow aloft helping to generate snow showers.

Friday night...As the upper trough moves to eastern South Dakota and low level winds decouple from the stronger winds aloft, winds will decrease somewhat in the evening, with strong winds ending across the I-80 Summit and foothills by late evening. Areal snow coverage will decrease during the late evening as low and mid level moisture wanes and lift decreases.

Saturday-Saturday night...Breezy day expected for Saturday under brisk northwest flow aloft and based on low level gradients, though much less windy compared to Friday. 700 mb temperatures near -2 Celsius will yield maximum temperatures near 50 degrees west of I- 25, with 50s to near 60 degrees east of I-25. Dry with minimal low and mid level moisture. A quiet night anticipated Saturday night under northwest flow aloft.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

Issued at 125 PM MDT Thu Apr 2 2026

Some shifts in the long-term forecast pattern have been noted on today's 12z guidance. A broad ridge of high pressure will be in place over the southwestern CONUS this weekend, resulting in a generally dry and tranquil forecast for southeast Wyoming and western Nebraksa. However, ensemble guidance has trended farther west and more suppressed with this ridge today, allowing for the high plains region to remain under the influence of northwest flow aloft. After a dry and mild day on Sunday with temperatures running around 10 degrees above average, forecast guidance is hinting at a weak band of frontogenetic forcing to set up somewhere from northeast Wyoming through western South Dakota and into western Nebraksa. These kinds of scenarios, driven by a potent gradient between a broad low pressure over the Great Lakes/Canadian shield and a ridge to the southwest, can often result in a band of shower activity and breezy weather throughout east-central Wyoming and into the NE panhandle. Forecast guidance has trended this direction today, and some shower activity with cloud cover is now possible on Monday in the aforementioned areas, with slightly cooler temperatures.

Forecast confidence decreases on Tuesday and Wednesday as a few very weak pieces of energy traverse the northern portion of the ridge over the southwest CONUS and bring an uptick in mid/upper level moisture in over the Rockies and High Plains. Very low-end chances of afternoon showers are present, but very poor spatiotemporal agreement among ensemble guidance exists with regard to the best chances for showers. With our region remaining on the fringes of the ridge with west to southwesterly flow in place, temperatures will continue to run 5-10 degrees above average despite the cloud cover and shower activity.

A more robust low pressure system and chance for precipitation over Wyoming and Nebraska still looks possible toward the end of next week. However, ensemble guidance has shifted to a more cutoff-low- pressure system look, with a slow-moving low pressure system moving through the Great Basin by Thursday/Friday. Showers and possibly some afternoon thunder are possible on Thursday along with warm temperatures, but any chances of heavier, steady precipitation now look to hold off until at least Friday. GEFS members in general remain more bullish and progressive with this system, whereas ECMWF ensemble guidance favors a slower system possibly getting absorbed by the next wave in the Pacific wavetrain. We will keep an eye on this timeframe as any precious moisture is worth noting given the extreme to exceptional drought ongoing throughout the entire west.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 1058 AM MDT Thu Apr 2 2026

A complex and challenging aviation forecast today for all terminals as showers move through the region. Scattered rain and possibly snow showers at RWL and LAR will move through this afternoon with potential for VIS dropping into the MVFR category and brief IFR ceilings in the heaviest precipitation. This system will move east through the afternoon and evening, affecting CYS with scattered showers, MVFR vis and IFR ceilings possibly in the 22-03z timeframe. Farther east, the next 6 hours will end up mostly dry in the Nebraska terminals, however around 0z onward, MVFR to IFR conditions are possible for both Ceiling and Visibility. A period of moderate steady rainfall is likely at BFF, SNY, CDR and possibly AIA from around 4z through 8z overnight. Very low confidence exists in specific timing for showers and possibly afternoon thunder, with very high dispersion amongst short-term models showing a very scattered nature to convective showers.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning from 6 PM this evening to 6 PM MDT Friday for WYZ106. High Wind Watch until 6 PM MDT this evening for WYZ109. High Wind Warning until 6 PM MDT Friday for WYZ110. Winter Storm Warning until 6 PM MDT Friday for WYZ112-114. High Wind Warning until 9 PM MDT Friday for WYZ116-117. High Wind Warning from 9 PM this evening to 6 PM MDT Friday for WYZ118. NE...None.