textproduct: Cheyenne

KEY MESSAGES

- High Wind Warnings are in effect for the typical wind prone areas of southeast Wyoming starting this afternoon.

- High Winds expected to occur in three phase, with minimal downtime between each phase.

- Warming trend through the start of the week, before the next system moves in mid-week.

- The probability for a significant and widespread wind event on Thursday and/or Friday continues to increase.

SHORT TERM /THROUGH TUESDAY/

Issued at 215 AM MST Sat Mar 7 2026

Quieter weather returns to the region this weekend through at least mid-week, with only strong winds expected Saturday through Monday and no precipitation chances until Wednesday. The upper-level trough is departing this region this morning with upper-level water vapor imagery showing the main trough axis along a line from about Rapid City, SD, southwest through Salt Lake City, UT, and slowly advancing southeasterly. The trough axis should clear the CWA by mid-morning, lead to northerly flow aloft returning as the upper-level ridge to the west tilts eastward. The ridge as a whole does not look to move much, with a low to the east, the upper-level pattern across the western CONUS looks like an Omega Block trying to setup today and remaining in place through mid-week. Usually, a setup like this would lead to mostly benign weather across the CWA, upper-level zonal flow will push the apex of the ridge to the south and lead to zonal, westerly, upper-level flow through about Wednesday morning. While the overall weather will be quieter than Friday, a prolonged high wind event will setup this afternoon through at least Monday afternoon. With zonal flow remaining in place for the work week, several other high winds events look likely, potentially lead to a very warm and windy week, especially across southeast Wyoming.

The primary threat for high winds this weekend through the start of the week will be Saturday morning through Monday morning, starting with Arlington Saturday morning and impacting all the wind prones by Saturday evening. This prolonged event is expected to occur in three phases, the first on Saturday afternoon/evening with a surface pressure gradient driven event, then an increasing surface pressure gradient with strong 700mb wind event Sunday morning/afternoon, and the final being the strong combination of strong pressure gradients, strong 700mb flow, and strong downward omega event late Sunday night through the morning on Monday. No changed were made to the High Wind Warnings, especially since minimal downtime is expected between each of the three phases playing out.

Phase one begins later this morning through the afternoon hours at Arlington/Elk Mountain as surface pressure gradients increase to 3- 4mb across the Arlington wind prone region and 700mb winds remain fairly weak, around 40kts at peak strength early this evening. Downward omega values are progged to be fairly strong, leading to downward acceleration of winds and, therefore, strong wind gusts at and near Arlington. Craig to Casper gradients will be a bit on the weaker side, only between about 50 and 60m through the evening. In- house random forest guidance suggests 60+% probability of high winds at Arlington, further increasing confidence for a gradient-driven event this afternoon. Wind gusts at Arlington up to 65mph will be expected with this first phase, with Bordeaux, the Summit, and Foothills likely remaining in the 40 to 50mph range this afternoon, starting to increase for Phase 2 in the evening and overnight hours.

Phase two starts later tonight through the overnight hours and into the afternoon hours Sunday. 700mb flow will begin to strengthen later tonight as a 700mb low over Canada moves further south, increasing height gradients across much of the Intermountain West and Pacific Northwest. The 700mb jet across the Laramie Range increases to around 50kts in response to the increasing height gradients by early Sunday morning, between 2 and 5 AM. Surface pressure gradients remain very strong across the CWA, as a high over western Colorado strengthens and a low strengthens across southern Canada, increasing pressure gradients as far south as northern Colorado. This phase will be one of the stronger two phases, with more locations potentially seeing high winds. Surface pressure gradients across the Arlington zone remain around 3 to 4mb Sunday evening into the overnight hours, with Craig to Casper gradients increasing into the low-60s overnight. Surface pressure gradients across the Laramie Range near Bordeaux and the I-80 Summit will be stronger, likely between about 4 and 5mb, resulting in very strong surface winds, likely gusting 75+mph. Elevated downward omega values will help mix down 700mb winds, helping surface pressure gradient- driven winds increasing as downslope acceleration comes into play as well. In-house random forest guidance keeps about a 80% chance for high winds at Arlington and about a 60% change at Bordeaux, increasing confidence in the wind event continuing through Sunday.

The final phase will combine all of the features we typically look for with high winds, resulting in it also being the other of the two strongest events, especially near Bordeaux, starting late Sunday night and continuing through Monday afternoon. Late Sunday night, the most zonal upper-level flow is expected to develop, leading to vertical stacking of stronger, zonal winds from 250mb down through the surface. 700mb height gradients will remain very elevated as cooler air pushes southwards, dipping heights down to the north while keeping them similar to the south. A 55 to 60kt 700mb jet is expected to remain in place across the Laramie Range, with a 700mb terrain-induced trough. Very strong surface pressure gradients continue Sunday night through Monday as the surface high over western Colorado strengthens and the surface low over southern Canada continues to strengthen and move eastward. The cold front associated with this low will increase surface pressure across the Northern Plains through Monday morning. With the CWA and wind prones sandwiched between two highs and having the lowest pressure between the two systems, surface pressure gradients will remain high. At the peak, the surface pressure gradient across the Arlington zone will be about 4 to 5mb, with similar gradients expected across the Laramie Range and the other zones. Downward omega values will be elevated again for the final phase of this event, adding downward acceleration to this breezy equation. Combining all of the features, strong winds will continue, likely gusting 75+mph throughout the period as well. The biggest difference with this final phase is the potential for strong, 700mb winds to spread eastward along with the best downward omega values. Wind prone-adjacent areas could see high winds with this final phase, namely central and eastern Laramie County, eastern Platte County, and potentially as far east as Kimball County in Nebraska. 750mb winds across central and eastern Laramie County, as well as eastern Platte County, are expected to increase up to 55 to 60kts late Sunday night, with downward omegas also pushing east, likely adding downward acceleration to the mix for these areas. In-house guidance suggests about a 20% chance for high winds in Cheyenne, and with this model we typically look for about 25% probability due to fewer number of training cases. Therefore, an eastward expansion of the High Wind Warning may be needed for the final phase of the event, but decided not to expand at this time due to some uncertainty. The highest uncertainty will be for western portions of the Panhandle, namely Scotts Bluff County souther through Kimball County, where 800mb winds are expected to increase to around 50kts, but downward omega values are not as impressive and, therefore, may not bring enough energy down to get high wind criteria. This will be something to watch over the next several days.

With highs winds comes warmer temperatures and dry conditions. Today will be the coolest day in the short term forecast period, with highs only in the low-40s to mid-50s across the region. Some uncertainty in maximum temperature exists for the Nebraska Panhandle this afternoon due to the speed at which the snowpack melts. If the snowpack starts melting quicker, highs in the mid-50s to potentially upper-50s would be expected. With a slower melting of the snowpack, cooler temperatures would be expected across the Panhandle. Nudged temperatures across the Panhandle down, due to a slightly higher likelihood of the snowpack taking longer to melt this morning into the afternoon hours. A warming trend returns Sunday through Monday with highs expected to be in the low-50s to upper-60s Sunday, mid- 50s to low-70s Monday, and low-50s to low-60s on Tuesday as a broad, upper-level trough starts to dip towards the region. Overall, expecting a warmer than average weekend and start of the week with limited to no precipitation expected until Wednesday onwards.

LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/

Issued at 215 AM MST Sat Mar 7 2026

As these two systems push off to the east Tuesday into Wednesday, the intermountain west may see the pressure gradient slightly relax and cause a mid level jetstream de-acceleration and temporarily suspend our high winds. However the jet will still maintain a speed of 45 to 50 knots giving us possibly elevated winds but its still a little uncertain if we will reach possible high wind criteria during this time as the global omega fields due suggest some maintaining of subsident flow over our wind prone areas. To further cement the idea that the gradient will relax enough to prevent high winds is the expansion of stronger rising motion across our forecast area as the subsident flow is shown to weaken across our wind prones. Our in house algorithm does also agree with this meteorological ideology as it maintains a 60 percent probability for elevated winds instead of High winds like the previous days. However, given we are still in westerly flow aloft the Intermountain west is prone to the development of strong mountain waves from that direction which still may give us high winds despite the lack of support from the jetstream itself. A brief ridge does push into the Intermountain West at this time which does generally help weaken the mountain wave potential while maintaining our warmer weather. From Thursday through the weekend, the ridge becomes more broad and less amplified as it dominates the Southwestern United states behind the earlier southern low pressure system continuing to push east into the Gulf region. Meanwhile another system (another one) pushes itself through the Canadian Providences from the Pacific Northwest. This arrival of a new system compresses the gradient against the broad ridge rejuvenating the high winds over the Intermountain west with the 700mb jet ramping up to 70 knots. So another high wind warning may come into existence later this week as well.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1020 PM MST Fri Mar 6 2026

Minimal aviation weather concerns as VFR conditions will prevail across all terminals for the duration of this TAF period. Winds overnight will be generally less than 10 knots. However, winds will ramp right back due to a strengthening 700mb jet, so expect westerly gusts in the 25-40 knot range by 19Z Saturday for all sites. At the tail end of this TAF period, LLWS may become an issue and it was added into the KCYS TAF. Other sites in the Nebraska Panhandle may need LLWS added, but it is expected just outside of this forecast.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning from 5 PM this afternoon to 6 PM MST Monday for WYZ106-116-117. High Wind Warning from 8 AM this morning to 6 PM MST Monday for WYZ110. NE...None.