textproduct: Cheyenne

KEY MESSAGES

- A winter weather advisory will go into effect for the Sierra Madre and Snowy mountains Sunday morning for snow accumulations up to 10 inches.

- 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 MONDAY/

Issued at 321 PM MST Sat Nov 29 2025

A short lived ridge moves over the Intermountain West for a quick break between systems. While it will be cold today the skies will stay relatively clear and winds rather light for the region this afternoon and evening. 700mb temperatures look to remain between -10 to -15C allowing for another night of temperatures in the single digits across Southeast Wyoming and the Nebraska Panhandle. Mid level water vapor already shows the next system pushing into the Pacific Northwest. This system is expected to track through the southern portion of Idaho and into the Northern portion of Utah and into Colorado. There is still a little discrepancy in the exact track of this system but overall consensus has the system tracking through the middle of Colorado confining most of our precipitation to the higher elevations in our southern counties. Some high-res guidance does take the storm a little further south causing some lighter snow accumulations but using the average Kuchera and 10:1 ratio for snow accumulations a range put between 6-10 inches for the Sierra Madre and Snowy Mountains. The adjacent areas could see between 2-4 inches from 11am Sunday through 5am Monday. The global models depict a band of frontogenesis and stream of vorticity setting up over Carbon and Albany county increasing the snowfall rates and overall accumulations. The Nam Nest has a slightly more Northern track and chose violence with total snow accumulations up to 18 inches for the 12z run using the Kuchera ratio. While an outlier diverting from the model consensus it can't necessarily be ruled out if the system were to wobble slightly North. THe HREF paints a neighborhood probability of 70 to 90 percent of seeing greater than 5.0 inches of snow over the Sierra Madre mountains and a 20 percent chance of over 5 inches for the SNowy mountain from Sunday night through 5 am Monday morning. The probabilities drop to 20 percent for greater than 10 inches for the Sierra Madre range and 0 percent for the Snowy range. This increases the confidence of snow accumulations between 6 to 10 inches prompting a Winter Weather advisory for the mountains.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Issued at 321 PM MST Sat Nov 29 2025

Long term remains active as we see a system bring gusty winds and precipitation chances to start the period, followed by a brief dry period alongside some warming to bring us back to near normal temperatures, but another approaching system at the end of the period will cause another potential high wind event alongside increasing precipitation chances once again.

The period begins Monday as we see high winds returning to the CWA thanks to an approaching trough and strong jet. Winds at 700mb late Monday through Tuesday should increase into the 50-60 knot range and, while not the strongest, downward omega values should be conducive enough to mix these winds to the surface primarily at our windiest spots of both Arlington and Bordeaux. In house guidance paints an 80-90% probability for Arlington, while Bordeaux sits a little lower in the 50-60% range, but still likely. With such consistency, the expectation is likely we'll see high wind warnings with this system. Meanwhile prior to the arrival of this, temperatures will remain several degrees cooler compared to normal on Monday, followed by a slight warmup that should place us around average on Tuesday. Then into Tuesday as the trough starts to move into the region, precipitation overspreads with temperatures also cooling thanks to the passing cold front. Expect as precipitation moves in later Tuesday through Wednesday, we should be cold enough at all levels to promote snowfall, but without a strong amount of QPF, overall accumulations should be fairly light - a few inches for the mountains, and around an inch or less for lower elevation locations, with some locally heavier amounts not out of the question and windy conditions promoting blowing snow and some locally high drifts.

Temperatures on Wednesday remain widespread at our below freezing for highs, but expect a gentle warming trend thereafter with highs warming into the 30's to 40's by Friday. The region will dry out on Wednesday, but Thursday into Friday we should see a return of light to occasionally moderate mountain snow thanks to upslope flow. And on the note of our flow pattern, models continue to indicate we'll be seeing our next high wind event Friday into Saturday with the approach of our next trough, with in house guidance already peaking into the 60-80% probability range for our wind prone locations. While overall active, overall current forecasts suggest our most impactful conditions will remain the region's usual high winds as we move into the start of December.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 405 PM MST Sat Nov 29 2025

Fairly benign to start the 00Z TAF period with mostly clear skies, decreasing winds, and no visibility reductions. Upper- level clouds move in after sunset with winds becoming light and variable. Primary aviation concern for the 00Z TAF period will be the incoming snow showers late in the period with increasing winds in the morning and decreasing ceilings ahead of the snow. VFR expected to prevail through the period at all sites except for KRWL, KCDR, and KAIA. KCDR and KAIA may see low-level ceilings early this morning, though confidence is low at this time.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Winter Weather Advisory from 11 AM Sunday to 5 AM MST Monday for WYZ112-114. NE...None.