829 FXUS65 KCYS 302353 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 453 PM MST Tue Dec 30 2025 .KEY MESSAGES... - Another brief, marginal high wind event is expected tonight into Wednesday morning for the wind prone areas. Additional high winds are possible Thursday morning. - Above average temperatures, breezy conditions and a chance of precipitation primarily in the mountains expected through early next week, with a pattern change possible late. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Issued at 330 PM MST Tue Dec 30 2025 Mild and dry weather has returned to the area today. GOES satellite imagery shows some high level cloud cover drifting southward across the area associated with a weak vort-max. Broad ridging is building back into the western CONUS with continued dry northwest flow aloft. Most of the area is seeing temperatures approximately 10F above average once again today, with most of the area in the 40s to low 50s. The pressure gradient across our mountain barriers has relaxed since this morning, but will begin to creep up again after dark today. This looks like another marginal wind event confined to the wind prone areas, and perhaps even a little more marginal that last night. Most high wind parameters are a tough weaker for tonight compared with last night, with the exception of the Arlington to Bordeaux MSLP gradient. In-house guidance is also more reserved, showing about a 30 to 40% probability for high winds in each of our wind prone zones. Overall, confidence is lower than last night in reaching high wind criteria. Still, decided to upgrade the Arlington/Elk Mountain area to a High Wind Warning since we observed numerous gusts of 60 to 65 mph this morning. The other two zones were left as a Watch due to lower confidence. The I-80 summit only briefly touched 58 mph this morning, while the Bordeaux area did not get close. While the slightly stronger pressure gradient over the Laramie range could lead to higher wind speeds at Bordeaux, the confidence is not there yet to issue a warning. Gradients will come down once again Wednesday morning, and lead into a very mild last day of 2025. NAEFS mean 700-mb temperatures climb to between +4 and +6C tomorrow, which will be around the 90th to 99th percentile of climatology. Expect to see highs reaching the mid 50s to low 60s over the High Plains and generally the upper 40s for the valleys west of I-25. Currently, no daily record highs are explicitly forecast, but we will be within a few degrees at several locations. Much of the area will be breezy on Wednesday, but high winds are not expected after about mid to late morning. Pressure gradients will climb once again, which may support additional gusty winds towards early Thursday morning. This event once again looks quite marginal. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 330 PM MST Tue Dec 30 2025 Long term will be semi-active as an upper level low pressure system moving inland from California weakens and moves across the Four Corners region, helping to disrupt the high pressure ridge controlling the area. While this ridge should then re- establish into the weekend, multiple systems will then begin riding the periphery of this feature, helping to begin slowly shifting and weakening it through the end of the forecast period, keeping some sensible weather concerns present for the CWA including winds and mountain precipitation. As mentioned, an upper level low moving inland will help to disrupt the high pressure ridge holding control of the region in the short term, allowing temperatures to stop their rising trend and hover in the 40's to 50's for highs on Thursday and Friday. Meanwhile we should see another brief increase in gusty winds, but still uncertain if it will be strong enough to warrant a high wind warning for our wind prone locations for Thursday. In house guidance indicates only a maximum of around 50% probability for gusts 58+ mph, and will be mostly gradient driven as 700mb support will be lacking. Still, knowing how our wind prone locations do like to over perform, wouldn't be surprised if we see another another round of products. Friday the 700mb jet should briefly re-strengthen and this combined with favorable surface pressure gradients will bring a higher risk of strong winds for our wind prone locations, this time with a slightly better probability (60-70%). Otherwise, this change should bring a little more moisture to the area alongside westerly to southwesterly flow, allowing for mountain precipitation to develop. Without significant forcing this should mostly be orographically forced in nature, with light to moderate snow in the Snowy and Sierra-Madre ranges. Snowy range may be shadowed by the southwesterly flow, but the Sierra-Madre range is currently forecast to see enough snowfall Thursday into Friday to warrant an advisory with around 6 to 10 inches possible. Over the weekend and into early next week, the ridge will start to re-establish, leading to a warmer day on Saturday with highs a few degrees warmer than the end of the week, but multiple systems riding the periphery of this feature will help to keep it slowly transient through the end of the forecast period, while also beginning to flatten the feature and keep our weather semi-active. Widespread winds through the end of the period look to remain breezy (gusting 20-40 mph), but in house guidance isn't as excited for any stronger wind events currently. Meanwhile generally westerly to southwesterly flow may fuel some light chances of precipitation in the high terrain, but once again a lack of significant features and lower moisture will preclude significant activity, with general light mountain snow showers expected. Temperatures should start to fall a few degrees each day though, keeping us above average as we move into the first full week of the new year but not a widespread record setting event compared to last week. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 453 PM MST Tue Dec 30 2025 VFR Conditions are expected throughout the TAF period. With the exception of a few high based clouds, skies will be rather clear. Winds may be a little gustier than forecast in the afternoon tomorrow but not by much. Otherwise winds are looking rather light compared to the past few days. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...High Wind Watch from 2 AM MST Wednesday through Wednesday morning for WYZ106-116. High Wind Warning from 11 PM this evening to 9 AM MST Wednesday for WYZ110. NE...None. && $$ SHORT TERM...MN LONG TERM...CG AVIATION...MM