textproduct: Cheyenne

KEY MESSAGES

- Locally dense fog is possible over portions of the High Plains Friday night into Saturday morning.

- Mild conditions are expected for Halloween (Saturday), though a few showers will be possible along and west of I-25.

- A complex but disorganized storm system will move into the area Sunday, bringing cooler temperatures and a chance for rain and high elevation snow showers.

- Widespread blustery conditions are anticipated Monday into Tuesday along and east of the Laramie range.

SHORT TERM /THROUGH SUNDAY/

Issued at 246 PM MDT Fri Oct 30 2026

Expect an uneventful rest of the day as the CWA sits at the edge of an upper-level ridge to the east. Some low stratus still lingers in the Nebraska panhandle, and will likely stay through the overnight hours. Places without cloud cover are having a pleasant, mild day, with highs in the 50s and 60s. Continued light southerly flow into the overnight hours will lead to another round of likely dense fog developing overnight and continuing into Saturday morning. An area from Cheyenne to Sidney to Alliance is the most likely area to see dense fog Saturday morning, making for a spooky start to Halloween!

Areas west of the Laramie Range will likely see a showery start to Halloween as a shortwave moves across the Rockies. Hi-Res guidance has precipitation moving into Carbon County early Saturday morning and moving eastward into Albany County by mid-morning. For the most part, Hi-Res guidance shows this as the areal extent of precipitation coverage, with showers dissipating before reaching the Laramie Range. Once the stratiform precipitation dissipates, a few isolated showers could still be possible during the afternoon, but overall looks like great trick or treating weather across the forecast area. Mild temperatures will continue for Saturday with highs in the 50s and 60s. By the evening hours, temperatures will fall into the 40s and 50s, perfect temperature to keep your candy from melting! The remainder of Saturday night will be uneventful, with the potential for more fog developing in the Nebraska panhandle overnight.

Sunday has the potential to be a much wetter day as a moisture-rich trough begins to push into Wyoming. Hi-Res guidance has stratiform precipitation moving into the southwest corner of the CWA during the morning hours with precipitation gradually filling in eastward. Precipitation coverage will be greater than Saturday, with some locations likely picking up some decent rainfall amounts. However, its likely still a bit early to nail down specific rainfall amounts as synoptic models still show disorganized upper-levels with this system. This system will become more organized on Monday after it exits the forecast area.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Issued at 246 PM MDT Fri Oct 30 2026

On Monday morning, southeast Wyoming and western Nebraska will sit in-between a surface low to the east in the Great Plains and an upper-level trough to the west over the northern Rockies. Despite the presence of nearby systems however, the day will likely start off mostly dry given a lack of favorable overlap of lift and moisture directly in our local vicinity. As Monday progresses, the upper-level trough to the west will swing eastward, and surface winds will shift out of the north. Lingering low-level moisture to the northwest of the surface low looks to get wrapped around the trough as it departs, increasing the chances of showers and possibly some snow showers to east-central Wyoming and potentially the NE panhandle. Ensemble QPF totals with the backside of this system on Monday afternoon/night still remain rather low and dispersive, similar to overnight guidance. Overall, it looks like only a tenth of an inch or so of QPF is likely east of I-25 and north of I-80. Higher amounts are possible in the northern Laramie range where favorable orographics and snowfall may last a bit longer. The other big story on Monday and Monday night will be a dramatic increase in winds on the backside of this system in the wake of a passing cold front. Ensemble guidance still is in strong support of winds possibly exceeding 50 mph, even approaching high wind criteria east of I-25 through the NE panhandle. The strongest period of high winds appears to be mid to pate afternoon, potentially over the I-80 corridor, as mixing is maximized at the time of the passage of the strongest mid-level jet aloft. The north to north-northwesterly orientation of surface flow could bring significant crosswind impacts to travelers along I-80 from the summit eastward through the high plains during this timeframe. As the high wind even diminishes on Tuesday morning, dry weather and above-average temperatures will move in for the remainder of the week. The synoptic pattern aloft does remain fairly active, with two weak vort-maxes passing by on Tuesday night and on Wednesday night. However, both of these systems will be starved of moisture and bring only occasional increases in mid and upper-level cloud cover through the area. Forecast confidence remains relatively high through the end of the week on both above normal temperatures and drier weather. However, by the end of the week, attention will turn to a larger system with upper- level support moving through the southwestern CONUS. Ensemble guidance is quite dispersive with both the track and the amount of moisture with this event, but there is a broad consensus that Wyoming and possibly western Nebraska will see some form of precipitation from this event given its more favorable storm track bringing in southerly and southeasterly flow. We will continue to monitor this system and potential impacts with both precipitation and winter weather in the high country as we start the month of November.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1152 AM MDT Fri Oct 30 2026

Main aviation impact today will be low stratus in the Nebraska panhandle. Light southerly winds will keep low-level moisture high, leading to persistent low stratus throughout the day. MVFR to IFR CIGs are anticipated for western Nebraska terminals. When winds become more calm overnight, the ample low-level moisture will likely lead to the development of fog for most terminals east of the Laramie Range. Visibility impacts can be expected, with MVFR to IFR conditions. Low stratus will stick around through the overnight hours.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.