textproduct: Cheyenne

KEY MESSAGES

- A winter weather advisory is in effect for the Sierra Madre and Snowy mountains for snow accumulations up to 10 inches.

- A High Wind Watch has been issued for the wind prone areas of southeast Wyoming beginning Monday evening.

- Long term remains active with multiple systems promoting prolonged periods of high winds alongside mountain snow and chances of lower elevation snow as well.

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

SHORT TERM /THROUGH TUESDAY/

Issued at 339 PM MST Sun Nov 30 2025

Mid-level water vapor shows the low tracking farther north than the models had it yesterday. Recent model runs have severely decreased QPF and snow accumulations. A weighted blend of old grids/NBM/NAM12 was used to retain advisory level snow accumulations for the mountains but also add in some light snow accumulations for almost everywhere east of I-25. As this system pushes east-southeast, the synoptic forcing from the low passing over Southeast Wyoming should be enough for light stratiform snow over the next 12 hours. While accumulations wont be anything substantial accumulation's of a few tenths can't be ruled out. There is also a little bit more moisture than what the global and hi-res models are advecting in. Surface dewpoints and RH levels are showing up a little higher than what the models are forecasting. So there should be a sufficient amount available to utilize that greater synoptic forcing to carry snow production outside of the mountains. As this system rides the CO/WY border it will drag cold dry air down from Canada abruptly ending the light snowfall early Monday morning. A 700mb jet starts to develop Monday afternoon causing the wind gusts to increase. Most of the models have the jet increasing between 60 to 65kts by 06z or midnight Monday going into Tuesday. Over the past couple runs the global omega fields have been steadily increasing the subsident flow over our wind prones concurrently with the increasing 700mb jet. Our in-house guidance still maintains high confidence (80-90% probs) of reaching high wind criteria by 00z Monday for the Arlington area. However, the timing of jet intensification provided by the models is a little delayed compared to our in-house guidance. Given there is a little bit more time before headline decisions have to be made. So, the watch was continued with no alterations to the timing.

LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/

Issued at 339 PM MST Sun Nov 30 2025

Long term remains active thanks to multiple systems bringing rounds of precipitation alongside long durations of high winds, with temperatures steadily warming during the later part of the week to bring us back to near normal by the weekend.

The long term starts on Tuesday as an upper level trough will sweep down the western US and will deepen into a near cutoff low, with the strongest part of the system remaining well to the south as this feature moves across the Four Corners area. But then moving into the weekend, a weak ridge will try and take over, but will be flattened by a quick moving trough into Saturday. Under this pattern, we'll see our first round of high winds beginning just before the long term on Monday and continuing into Tuesday afternoon, weakening thereafter. A high wind watch is already out through 03Z Wednesday for our usual wind prone locations, and we will likely see that upgraded within the next 24 hours as models have remained consistent on 700mb winds in the 60-70 knot range, favorable downward omegas, and strong, favorable pressure gradients across the area. In house guidance continues to produce a 70-80% probability of high winds as well, leading to very high confidence. Meanwhile a few models have shown some increased QPF which would lead to higher snowfall, but the majority of ensembles and the NBM are keeping QPF in the mountains and to our south, so the expectation remains we'll see amounts high enough to warrant products, at least advisories, in the mountains, with around 1-3 inches in the lower terrain thanks to shadowing effects.

Moving into Wednesday and Thursday, both days should be relatively calm and dry as the ridge tries to build in, but our winds will once again begin increasing on Thursday in response to the next approaching system as pressure gradients tighten and the 700mb jet begins to re-establish and remain firmly planted over the CWA through the weekend. In house guidance continues to highlight this period and with such consistency there is moderate to high confidence in a multi-day high wind event once again for our wind prone regions. Meanwhile models expect that this flow should allow for more chances of mountain snowfall with some of this able to spill over into the adjacent high plains, but once again shadowing effects are likely going to limit how much accumulation we can produce outside of the high terrain. Finally our temperatures start off near normal on Tuesday with highs in the 30's to 40's, dropping notably on Wednesday thanks to the passage of the front with the first system and highs not making it out of freezing, but as the ridge tries to take control through the weekend a modest warming trend should bring us back to the 30's and 40's by Saturday.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1012 PM MST Sun Nov 30 2025

Snow showers are slowly tapering off across southeast Wyoming and western Nebraska. IFR ceilings have remained behind at KCYS, with MVFR to near-IFR ceilings possible at KLAR in the next few hours. Ceilings remain at VFR status in the Panhandle, though visibility will fluctuate with remaining snow shower activity across KBFF, KSNY, and KAIA for the next 1 to 3 hours. Clouds slowly clear out overnight with light winds. Gusty conditions return for the afternoon hours with clear skies expected at most terminals.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Watch from Monday evening through Tuesday morning for WYZ106-116-117. High Wind Watch from Monday afternoon through Tuesday evening for WYZ110. Winter Weather Advisory until 5 AM MST Monday for WYZ112-114. NE...None.