textproduct: Cheyenne

KEY MESSAGES

- An arctic front will move across the region tonight, bringing much colder temperatures along with light snowfall accumulations to the forecast area through the weekend.

- Very active long term forecast expected with multiple troughs moving through and promoting snow chances, as well as a high wind event possible Tuesday.

- Temperatures will remain very cold through mid-week, before a weak warming trend arrives Wednesday onwards.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 135 PM MST Fri Nov 28 2025

The big story in the short term will be the arctic front that dives south across the CWA late this evening and through the overnight hours. But first, enough lift and instability is in place to increase precipitation chances this afternoon. Scattered light snow showers will begin west of the I-25 corridor and spread east. As it does, some of the precipitation may transition to a rain/snow mix or all rain with a northern surge of warmer air in the mid-levels, helping surface temps climb into the 40s and 50s for many locations, warmest east of I-25. By this evening, as the front approaches, in- house guidance depicts decent parameters for the likelihood of snow squalls, with the greatest threat west of Cheyenne. Timing will play a big role, winds are slated to decrease this afternoon which limits the snow squall potential, but this will be monitored as any burst of snow could reduce visibility along highways. Then we go into the late evening and overnight hours, as the arctic front approaches closer to the CWA, widespread snow chances increase along with winds shifting and becoming gusty from the north. With north winds, orographic enhancement will increase snow totals, places such as Pine Ridge or any city on a north facing slope. Snow accumulations appear to be minor in the Cheyenne area, generally less than an inch, while higher amounts to the west and north, with many places seeing 1 to 4 inches, greater in the mountains and along Pine Ridge. Due to orographic effects along with higher QPF values, Pine Ridge could see snowfall totals in the 3 to 5 inch range. With a swath of up to 5 inches of snow stretching from Converse east to Dawes County, Winter Weather Advisories are in affect from 8 PM tonight into Saturday morning. Confidence is high regarding snowfall amounts due to good agreement between the deterministic models and ensembles. As mentioned earlier, winds will shift to the north, this will allow a surge of cold Canadian air to move into the CWA, making temperatures plummet tonight with lows bottoming out in the low teens to single digits in many places.

This front and associated precipitation will have pushed off to the east by Saturday, with any lingering snow showers ending by the early afternoon hours. Cold air will have settled in, and don't expect that thermometer to rise much for the high, as highs Saturday look to only top out in the teens to 20s while lows plummet once again to near zero, especially across eastern portions of the CWA, where skies remain clear longer.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 135 PM MST Fri Nov 28 2025

Fairly active long term weather forecast for southeast Wyoming and western Nebraska as multiple troughs dig through the region throughout the week. On Sunday, the first upper-level trough expected this week is progged to push into the Intermountain West early Sunday morning before strengthening through the late-morning hours. Ample 500mb cyclonic vorticity advection will eject out from the jet and push across the CWA. In combination with the left exit region of the upper-level jet across the CWA, ample synoptic lift is expected with this positively tilted, upper-level trough. 700mb flow will remain fairly messy, as a closed 700mb low attempts to develop before transitioning to an open wave east of the CWA. Despite the messy flow, southeasterly 700mb flow is expected across the Sierra Madre and Snowy Ranges, which is a favorable upslope flow regime, specifically for the Sierra Madres. Snow is expected to start across the higher terrain as early as 12Z Sunday morning. With ample lift and moisture across the region, mostly cloudy skies will develop and keep the region cold for an additional day. As the 700mb system pushes through, a surface trough will develop with an attendant cold front, dropping 700mb temperatures into the -12 to -10C range, from the -9 to -6C range, by the early morning hours Monday. As a result, surface high temperatures will remain in the teens to 30s for the entire region, with overnight lows into Monday morning in the single digits. Luckily, winds should remain fairly light throughout the day Sunday, though they will be strong enough to drop the apparent temperatures into the teens across southern portions of the region and single digits across the furthest north locations. Overall, another chilly day expected Sunday, prolonging this cold snap into next week.

Cold conditions will continue into the day Monday as the upper-level trough pushes over the CWA, funneling continental arctic air from Canada into the region. The trough will begin to pinch off throughout the day Monday as the next upper-level trough from Canada digs into the northwestern CONUS, with very brief ridging possible early Tuesday morning. The departing and weakening upper-level trough will keep 700mb temperatures in the negative single digits Monday, before a briefly warming into the -3 to 0C range for the early morning hours Tuesday. With the transitioning upper-level pattern, Monday will be mostly dry, though cold. Surface high temperatures will remain in the mid-20s to mid-30s Monday. Winds begin to increase throughout the day Monday, with high winds possible on Tuesday. With the cooler temperatures and increasing winds, apparent temperatures will remain in the teens to 20s for the afternoon on Monday. Overnight lows Monday into Tuesday will be a bit warmer, thanks to the brief upper-level ridging expected Monday night into early Tuesday morning. Tuesday morning lows will only bottom out in the teens to mid-20s, much warmer than the single digits from the night before.

The warming will be short-lived as the upper-level ridging quickly gets shunted to the east early Tuesday afternoon and the next upper- level trough pushes into the region. Snow chances increase west to east on Tuesday as the positively tilted, upper-level wave moves into the region and the CWA once again remains in the left exit region of the upper-level jet. 700mb temperatures will tank back into the -10 to -8C range Tuesday afternoon and evening as the attendant cold front surges through. Prior to the cold front arriving, a brief zonal pattern will develop across the CWA Tuesday morning into the afternoon hours at 700mb. A brief period of enhanced height gradients at 700mb will increase the low-leve jet to around 50 to 55kts, with pockets around 60kts, across the Laramie Range. Downward omega values increase Tuesday morning and afternoon as well, leading to ample downward mixing through the day. In addition to this, the Craig to Casper 850mb gradient increase to over 70m, with the 700mb gradient approaching 60m. In house guidance is very excited about this event, with a 90% probability of high winds at Arlington and 70% probability at Bordeaux. With all these factors combined, strong to near-high winds are likely Tuesday afternoon in the wind-prone regions.

The remaining long term period is dominated by upper-level troughing, cold 700mb temperatures, and daily snow chances across the region. The previously mentioned trough stays over the region through Friday before the next upper-level trough moves in and pushes the aforementioned trough off the east. Temperatures for the remaining week will warm slightly, though 20s, 30s, and 40s are still likely across the region. In-house guidance is hinting at another high wind potential Friday, with about a 50% probability at this time. Things will still change between now and Friday, but did start increasing the winds late in the period to start hinting at the next possible high wind event across the region.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 431 PM MST Fri Nov 28 2025

VFR Conditions will likely turn into IFR conditions once the cold front hits and it starts to snow. Ceilings are also likely to drop between 600ft to 2,500ft by 06z with visibility to start dropping below 3SM with the wind and snow. KCDR will likely be in IFR conditions the longest as the system pushes ENE out of the region. Winds are expect to slowly die down by 18z tomorrow.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Winter Weather Advisory from 8 PM this evening to 8 AM MST Saturday for WYZ101-102. NE...Winter Weather Advisory from 8 PM this evening to 11 AM MST Saturday for NEZ002. Winter Weather Advisory from 8 PM this evening to 8 AM MST Saturday for NEZ095.