textproduct: Cheyenne

KEY MESSAGES

- Arctic cold front will linger across the eastern plains Sunday with cold temperatures and some patchy freezing fog across western Nebraska.

- Warming trend expected later today through early next week with strong winds returning to southeast Wyoming Tuesday through Thursday.

- Next chance for precipitation on Wednesday with periods of snow and rain possible.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 225 AM MST Sun Dec 14 2025

Less active early this morning compared to yesterday as winds have diminished substantially. Arctic cold front still remains over the area as a stationary front, positioned just west of the Interstate 25 corridor near the Laramie Range. Temperatures are in the teens and upper single digits well to the east of the front including far eastern Wyoming and most of western Nebraska...with 20s near the stationary front. Further west, temperatures remains in the 30s to low 40s. Some patchy fog and low clouds have been observed across the central and southern Nebraska Panhandle...mainly impacting Box Butte, Morrill, and Cheyenne counties with visibility below 1 mile at times. Do not expect this fog to last too long this morning, so not expecting to issue a Dense Fog or Freezing Fog Advisory. Fog should lift around sunrise as the arctic front begins to retreat eastward.

All models in good agreement for today and Monday and show pleasant and benign weather for mid December. Models and all ensemble guidance show the arctic cold front retreating eastward slowly by late this morning and into this afternoon. Models have trended a bit slower with movement of the stationary front, so lowered high temperatures across portions of the Nebraska Panhandle to reflect this trend. Further west, expect highs in the mid 50s to low 60s across southeast Wyoming and far western Nebraska. This will result in a pretty nice day with relatively light winds. Similar weather expected for Monday as 700mb temperatures remain between 3c to 7c...resulting in afternoon highs a few degrees warmer compared to today. Winds will start to increase over the wind prone areas of southeast Wyoming early Monday morning, but High Wind criteria is not expected at this time.

For Monday night, low to midlevel pressure gradient begins to increase ahead of the next Pacific system, forecast to impact Wyoming as early as Tuesday...but mostly on Wednesday. 700mb winds will climb above 50 knots later in the period towards day break on Tuesday. Increased winds using in-house wind guidance as a template. Low level subsidence is expected to be delayed by several hours with this event, with subsidence peaking closer to Tuesday morning...even though 700mb winds climb above 50 knots after midnight Monday night. Since this event is still 48+ hours out, will not issue any High Wind headlines quite yet due to the subtle timing differences discussed above. Did increase wind gusts above criteria and will likely need a High Wind Watch shortly. This wind event looks like it will mainly impact the wind prone areas to start off, with windy conditions expected in the high valleys and the eastern high plains.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 235 AM MST Sun Dec 14 2025

Long range forecast generally on track, made a few tweaks to winds and temperatures as we head into Wednesday through late in the week. In-house wind guidance continues to show a few more wind events...with a second one on Wednesday and Wednesday night, and possibly a third starting Thursday night. The third event Thursday night/Friday may become more widespread over southeast Wyoming with the 00z GFS showing 85+ knot winds near the Laramie Range and apparent mountain wave activity likely extending eastward into the western Nebraska Panhandle. Other models aren't quite as strong, but still show a solid 70+ knots. Confidence is limited of course since it is still 5 days out, but the high wind signal is showing up in the 25th to 75th interquartile spread of the grand ensemble.

Increased POP Wednesday and Wednesday night as the Pacific trough moves through the region. Seems to be enough forcing along the Pacific cold front for rain and snow even in the lower elevations. Increased POP a bit to reflect this trend.

Previous LONG TERM discussion... Issued at 111 PM MST Sat Dec 13 2025

For the longer term things may not be as zonal aloft as once thought with multiple shortwaves likely to traverse the crest of the flattened ridge. Thursday then looks to bring a much more amplified and impressive wave to the northern rockies with a 700mb jet crossing right through the southeast Wyoming plateau and mountain gap areas. Guidance much more heavily favors this system to bring high winds to the region with greater than a 70% confidence from the random forest model that this will meet high wind warning criteria which is an impressive signal for something 5-6 days out. Along with the very likely high winds, this system should also bring moisture to the west with some high elevation snow. However with it falling over a multi day period it would be unlikely to meet advisory criteria.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1020 AM MST Sun Dec 14 2025

VFR conditions for all (once the low stratus decides to move out the NE terminals. Winds variable at times but under 10kts at most points and thus not impactful to operations. For the Nebraska sites as mentioned above cigs in the LIFE to IFR threshold will remain in AIA, SNY, and BFF for the next few hours as the cloud bank pulls back to the east and have utilized a tempo for the next 3 hours at those sites to capture the uncertainty with then things truly go SKC.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.