textproduct: Cheyenne

KEY MESSAGES

- Moderate to heavy mountain snowfall expected through Thursday, mainly above 8500 feet. A Winter Storm Warning and Winter Weather Advisory are in effect.

- Snow squalls will again be possible for along and west of the Interstate 25 corridor Wednesday afternoon.

- Light to moderate snowfall is possible over the Plains Wednesday night into Thursday, followed by temperatures falling below seasonal averages for the end of the week.

- A Winter Weather Advisory has been issued for east central Wyoming, including Douglas and Lusk, starting this evening and continuing Thursday morning. This Advisory may be extended eastward into the western Nebraska panhandle later.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 305 AM MST Wed Feb 18 2026

First Pacific storm system of a "set" has lifted well to the northeast of the forecast area early this morning with deceptively quiet conditions reported across the region. Winds have continued to dissipate and any returns on radar have been confined to the mountains. However, we still have to get through the second potent upper level trough later today, and possibly a third one on Friday...with widespread snowfall looking likely across much of the area.

IR Satellite loop shows the next potent upper level trough pushing eastward across the Great Basin region at this hour. Models have been consistent and show this trough lifting northeast and becoming negatively tilted as it moves into the northern and central Rocky Mountain Region. At the surface, 00z models show a deepening surface low across northeast Colorado, near the base of the upper level trough, with an inverted surface pressure trough extending northwest into eastern Wyoming. This surface trough pretty much runs parallel to the Laramie Range tonight as another reinforcing shot of colder air moves southward out of Canada. Thus, this storm system will have plenty of cold air to work with (which has been the exception to the rule this winter it seems) and a decent amount of surface convergence and forcing. The only detail that is going to be the difference between light snow accumulations and near- Winter Storm criteria is the speed of the system and the movement of the low. As of right now, synoptic models are all trending towards a more progressive system with the surface low and associated upper level trough already in their weakening phase by Thursday morning. The surface low also takes on a more west to east motion across the plains, instead of a more preferred southwest to northeast route in the same area.

For this morning, expect snow to redevelop across Carbon and Albany counties over the next several hours with bands of moderate to briefly heavy snow showers possible. Winds are expected to increase late this morning and this afternoon, so some of this activity may be snow squall or squall-like in nature with favorable conditions this afternoon due to ample boundary layer moisture, instability, and 100 j/kg to 300 j/kg of CAPE to work. An area of moderate frontogenesis is also expected to move over this area today enhancing the risk. Preferred to handle this hazard with Snow Squall Warnings instead of Winter Weather Advisories since we had similar conditions yesterday with a limited amount of surface accumulation. Will likely see better snow accumulation today with the colder air, but the axis of convergence and forcing will quickly shift east of Carbon county. Still, 1 to 2 inches of snow are possible in the lower elevations west of the Laramie Range with a few spots close to 3 inches. The Winter Storm Warning for the Sierra Madre Range still looks good this morning, with a few SNOTEL sites already near 12 inches of snow...with more on the way and starting over the next few hours.

Further northeast, issued a Winter Weather Advisory for the northern Laramie Range, Converse & Niobrara counties starting late this afternoon. All high res guidance and synoptic models show a persistent axis of convergence in this area with additional upslope northerly flow developing after sunset as the surface low to the south strengthens. Total snow accumulations should generally be 3 to 5 inches with 4 to 8 inches of the N. Laramie Range. With the banded nature of the snow, a few locations across the lower elevations may see 6+ inches. However, with how fast the surface low and precipitation moves to the east, believe the moderate to locally heavy snow will be brief.

Far southeast Wyoming and the western Nebraska panhandle have the lowest confidence with this system. High res guidance continues to show some moderate to heavy snow accumulations, although models trends from the NAMNEST and HRRR have generally showed a progressive solution as well. The NAM shows the heaviest snow near the Wyoming/Nebraska border and extends this area of snow across the central and southern Nebraska Panhandle while high res guidance puts the bulls eye over the northern Panhandle. Guessing that the NAM is expecting rapid cyclogenesis and a deeper surface low, but not seeing any evidence of that in the other model output. We still have some extra time before the snow starts, so decided to give the next shift another look at it before deciding on Advisory as opposed to Winter Storm Warning. For now, kept the highest accumulations over the Pine Ridge with favored northerly upslope flow and most models showing the TROWEL hanging around the area for a longer duration. Further south, kept snow accumulations generally around 1 to maybe 2 inches at best, due to the potential of downslope west to northwest winds. Will continue to monitor model trends as these systems tend to be tricky and may change at the last minute.

Speaking of winds(!) in-house wind guidance across the wind prone areas of southeast Wyoming took a noticeable upward trend in the potential for strong winds, mainly over the I-80 Summit/southern Laramie Range, with another weaker signal over the Arlington/Elk Mountain area. This makes sense given how rapidly the surface low develops and intensifies tonight. Issued a High Wind Watch for the I-80 Summit and foothills late this evening through the middle of Thursday morning for gusts around 65 MPH. Keep in mind, if this surface low fails to develop and/or intensify, winds may be considerably weaker in this area.

By late Thursday afternoon, this potent storm system is forecast to push east of the area and redevelop across the Great Lakes region later this week. Snow will gradually end from west to east, with the northern Nebraska Panhandle hanging onto light snow into Thursday evening. Snow pack and clearing skies may set up a very cold night into early Friday morning with forecast lows below zero. Winds should be light, so not thinking about Cold Weather Advisory (for Wind Chill) quite yet.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 424 PM MST Tue Feb 17 2026

Long term begins active as we see multiple systems passing across the region, bringing some more chances of fairly widespread precipitation alongside breezy but not quite high winds, with ridging then returning and bringing what else - above normal temperatures and dry conditions to end the weekend start next week. Thursday evening begins on the backside of a quick moving shortwave, with transient ridging briefly taking over early Friday, but by Friday evening another shortwave from a deeper low in Canada will swing across the region. This will be followed by stronger high pressure starting to overtake the area, but a third shortwave from the aforementioned Canadian low will ride the periphery of this ridge and just graze our area Saturday afternoon before ridging then becomes the dominant feature into early next week, with perhaps one more shortwave riding this feature on Sunday but weaker than the previous ones.

Based on this pattern, the primary sensible weather concerns will involve precipitation chances, temperatures, and winds. For precipitation - while not a guaranteed chance across our area, probabilities continue to rise for light snow overspreading even into the Nebraska Panhandle by Friday evening. Outside of our western high terrain zones, the NBM now paints a 20-40% probability of 0.5 inch or more of snowfall from Cheyenne to Sidney and as far north as Wheatland and Scottsbluff. Temperatures meanwhile should be cold for once this winter, with highs on Friday widespread at or below freezing (hard to believe, right?). Highs remain in the 30's to low 40's through the weekend, putting us below to near normal through Sunday. This also will promote very chilly overnight lows, including Thursday night into Friday lows in the single digits to negatives, with apparent temperatures widespread in the negatives. Single digits to teens can then be expected into early next week. To start next week however, we'll be back up well above average as the ridging and warmth finally catch back up, with 50's back in the forecast for locations around and east of I-25, and long range models just beyond the long term indicating 60's by Tuesday. Finally, the passing trough on Saturday will bring a chance at some enhanced winds, but probabilities remain too low to consider high wind events currently. In house guidance only peaks at a 40% probability of high winds at that time, and both 700mb winds and pressure gradients aren't quite what we'd like to see to promote a stronger wind event.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 500 AM MST Wed Feb 18 2026

Snow will develop from west to east today through tonight as a secondary potent Pacific storm system moves into the region. Conditions will gradually deteriorate with periods of light to moderate snow for most locations, and even a few snow squalls for southeast Wyoming.

HAZARDS/WEATHER TRENDS: KRWL, KLAR, and most of the western Nebraska terminals have the best chance to see periods of IFR conditions starting this morning for KRWL, but not developing until 03z to 09z Thursday for KCDR, KBFF, and KAIA. Tried to time the IFR conditions and moderate snow for KRWL and KLAR, but there will be some degree of natural variability with snow showers and squall activity. KCYS and KSNY are the most likely terminals to remain VFR through most of the next 24. Added a few PROB30 groups for the most favorable timing for snow. Otherwise, light winds this morning will gradually increase this afternoon and tonight out of the south or southwest this afternoon and then shift more northerly tonight. Gusts 30 to 40 knots possible for KRWL, KLAR, and KCYS tonight as a surface low pressure strengthens to the east of the region.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Winter Weather Advisory from 5 PM this afternoon to 11 AM MST Thursday for WYZ101>103. Winter Storm Warning until 5 AM MST Thursday for WYZ112. Winter Weather Advisory until 5 AM MST Thursday for WYZ114. High Wind Watch from this evening through Thursday morning for WYZ116-117.

NE...None.