textproduct: Cheyenne

KEY MESSAGES

- Widespread snowfall is expected Thursday night through Friday, with accumulations of 2 to 4 inches in the Winter Weather Advisories, and a dusting to 2 inches outside of the Advisories.

- Winter-like temperatures in the teens to low 20s are expected by Saturday morning, creating a risk for outdoor irrigation and sensitive vegetation that has emerged from winter dormancy early.

SHORT TERM /THROUGH SUNDAY/

Issued at 324 AM MDT Fri Apr 17 2026

Blustery conditions continue behind the strong cold front that moved through earlier Thursday night. Precipitation behind the front so far has been minimal, with only a few sites across the forecast area reporting snow. Currently, most snow is falling in Carbon and Converse Counties, with webcams from these areas showing light accumulations on grassy areas. As the surface low continues to track southeast with front, precipitation will fill in further eastward into extreme southeast Wyoming and the Nebraska panhandle. Hi-Res guidance like the HRRR shows precipitation moving into the areas by mid-Friday morning and continuing into the afternoon hours. Stratiform precipitation will start to transition to more shower-like precipitation later in the afternoon as some peaks of sun could lead to pockets of instability. Model soundings from the GFS show up to a few hundred joules of CAPE during the afternoon hours which could lead to some spotty showers once the stratiform moves out. Snow accumulations with this progressive front will be on the lighter side, with the greatest accumulations expected west of the Laramie Range and in Converse County. Here, most locations are in a Winter Weather Advisory for roughly 2 to 4 inches of snow. Synoptic ensembles also are generally on board with these totals as well as Hi-Res guidance. On the east side of the Laramie Range, snow totals are expected to be less, with anywhere from a dusting to 2 inches expected. Given the warm ground temperatures further east, it is possible that snow will not stick, however, decent snowfall rates may overcome the warm ground and lead to minor accumulations. Any remaining showers will taper off during the evening hours on Friday, leading to a chilly overnight. Clearing skies and calmer winds will lead to overnight lows falling into the teens and low 20s across the area.

High pressure will begin to build into the Rockies on Saturday as upper-level ridging takes hold of western CONUS. The ridge will begin to push cold air out of the region allowing warmer air to take its place. High temperatures on Saturday will be much warmer than Friday, however still below normal for this time of year. West of the Laramie Range, highs are expected to be in the 40s, while temperatures east of the range will be in the 50s. Highs will be roughly 5 to 8 degrees below average for mid-April. With the ridge building in, precipitation chances will be minimal, but cannot rule out a stray shower in the northern Nebraska panhandle as residual moisture and energy from the trough push out during the afternoon.

The return to warmer and drier weather is expected on Sunday. 700 mb temperatures will climb back above 0C, leading to above average highs in the 60s and 70s. Subsidence under the ridge will ensure that mostly sunny skies keep conditions dry with no precipitation chances.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Issued at 311 PM MDT Thu Apr 16 2026

The long term period will begin under a high amplitude mid-level ridge resulting in dry conditions with above-average temperatures, translating to forecast highs in the mid to upper 60s east of the Laramie Range with 50s further west. Longwave ridging will remain in place over Southeastern Wyoming and Western Nebraska heading into Monday, resulting in median 700 mb temperatures exceeding the 95th percentile for our entire area per LREF guidance. While this won't translate to record-breaking high temperatures at the surface (76 degrees is the record for Cheyenne, recorded back in 1989), we will continue to see anomalously warm temperatures of 15-20 degrees above climatology. Mean 700 mb flow looks to be rather relaxed at around 20 knots, so high wind highlights aren't anticipated at this time. This is supported by in-house random forest guidance which has the wind-prone areas at < 20% probabilities of meeting high wind criteria. However with ensemble guidance showing 75th percentile wind gusts exceeding 20 mph and RH values of 15-20%, fire weather highlights may be needed as we get closer to Monday. Any beneficial moisture we can get from the system on Friday and earlier in the weekend would help mitigate these concerns.

Tuesday, the ridge axis will be situated over the eastern half of Wyoming with 500 mb heights exceeding the 90th percentile relative to climatology. Unsurprisingly, this will be accompanied by another day of high temperatures around 20 degrees above-average. In fact, some of our Nebraska counties will likely exceed 80 degrees. On Wednesday the ridge axis will shift east of Wyoming and Western Nebraska ahead of a closed 500 mb low, placing us in broad SW mid- level flow. While large-scale forcing for ascent appears rather weak, ensemble guidance is hinting at a narrow band of enhanced 700 mb frontogenesis east of the Laramie Range. This mesoscale forcing for ascent will become more clear and quantifiable in future forecasts, however in combination with PWAT anomalies around the 90th percentile, a chance of showers and perhaps a few thunderstorms seems appropriate at this time, most likely confined to the higher terrain. Thursday will continue to be unsettled, however temperatures look to remain above-average as we remain in a SW flow regime.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1123 AM MDT Fri Apr 17 2026

A weather disturbance aloft will move across the forecast area today, with strong northwest flow developing for tonight and Saturday.

Wyoming TAFS...High confidence in ceilings from 5000 to 9000 feet at Rawlins until 01Z, then clearing skies as the weather disturbance moves away. Gradients suggest winds gusting to 25 knots untl 01Z, and after 15Z Saturday.

For Laramie and Cheyenne, moderate confidence in ceilings from 1500 to 3500 feet through 02Z, with a weather disturbance producing occasional light snow and visibilities to 3/4 mile, then scattered to broken clouds prevail after 02Z. Winds gusting to 30 knots until 02Z, and to 30 knots after 15Z Saturday.

Nebraska TAFS...For Chadron and Alliance, moderate confidence in ceilings near 8000 feet until 02Z, with a weather disturbance producing light snow and visibilities to 3 miles with ceilings near 2000 feet, then skies will become clear after 02Z. Gradients support wind gusts to 28 knots until 02Z, and to 30 knots after 15Z Saturday.

For Scottsbluff and Sidney, moderate confidence in ceilings from 2500 to 5000 feet until 02Z, then clearing skies. A weather disturbance will produce light snow and visibilities from 3/4 to 4 miles with ceilings near 1500 to 2500 feet. Gradients support wind gusts to 30 knots until 02Z, and after 15Z Saturday.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Winter Weather Advisory until noon MDT today for WYZ101. Winter Weather Advisory until 3 PM MDT this afternoon for WYZ103>105-109>111-113. NE...None.