textproduct: Cheyenne

KEY MESSAGES

- High Wind Warnings and Red Flag Warnings remain in effect through 6 PM today.

- A cold front pushes through Tuesday bringing isolated to scattered precipitation chances across the region and cooler temperatures for Wednesday.

- A potentially dangerous, high wind event is taking shape for Thursday, with gusts 80-100mph looking increasingly likely, especially in the wind prones and wind prone adjacent areas.

- Very strong winds expected to continue through the start of next week, with minimal precipitation chances.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 318 AM MDT Mon Mar 9 2026

A very windy week is in store for southeast Wyoming and western Nebraska, though a lull is expected Tuesday and Wednesday. Upper- level flow on Monday will be largely zonal, shifting to southwesterly as the upper-leve trough over southwest Canada meanders slightly south throughout the morning hours. Westerly flow persists down at 700mb all day today, with elevated gradients leading to the 700mb jet peaking around 55 to 60kts later this morning. Surface pressure gradients will increase today as a surface low develops west of the Black Hills and advanced southeasterly through west-central South Dakota. As a result, surface winds will remain strong throughout the day, especially across the typical wind prone areas of southeast Wyoming. The High Wind Warning remains in effect through 6 PM this evening. Temperatures will be warm as dry, downsloping winds warm surface temperatures into the mid-60s to mid- 70s east of the Laramie Range and mid-50s west of the Laramie Range. With dry, downsloping ongoing for the second day, afternoon humidity is expected to drop into the 13-20% range, with winds gusting between 35 and 55 mph depending on location. The Red Flag Warning will remain in effect this afternoon, and has been expanded to include central Laramie County once again. Linger snowpack has melted and with fairly breezy, downsloping, westerly winds overnight ground moisture is anticipated to evaporate overnight, leading drier then originally thought afternoon humidity values. Therefore, the Warning has been expanded to include this area.

As the surface low develops Monday and moves southeastward, a trailing cold front will move across the CWA starting in the early morning hours Tuesday and continuing through the afternoon hours. The front is expected to get hung up on the Laramie Range, likely resulting in warmer temperatures closer to the Range and much cooler temperatures outside of this area. Temperatures will be in the upper- 40s to mid-50s in the northern areas and low-50s to low-60s across southern portions of the CWA. Unfortunately, moisture is not expected to be much with this surface system, so precipitation chances remain quite low, around 30-40%, for most of the areas. The far eastern Nebraska Panhandle areas from Chadron down to Alliance may see slightly more moisture and prolonged rising motion due to the front stalling as it is caught up along the Laramie Range, increasing precipitation chances across this area. However, total accumulation is expected to be low. Tuesday into Wednesday morning will be the best, if not only, time precipitation looks likely through the work week, with increasing chances over the weekend.

Wednesday will be the coolest day this week as the cold front pushes through and a weak upper-level trough helps funnel in cooler air from Canada. Temperatures are expected to be in the mid-40s to low-50s everywhere. Mild weather is expected as the CWA is positioned on the back side of the departing upper-level jet. Even 700mb winds look to remain fairly tame through the afternoon hours. With subsidence moving in behind the trough, skies are expected to clear, though breezy conditions will continue. This cooler, quieter weather will be very short-lived as a 700mb trough begins to develop over southern Canada and 700mb height gradients begin to significantly increase through Wednesday evening into the overnight hours.

Thursday will be the most active day in the short term forecast period as a widespread, impactful, potentially damaging, high wind event is expected to set up across much of southeast Wyoming and potentially into western Nebraska. Northwesterly upper-level flow continues for Thursday with a strong, 250mb jet to the north and east of the CWA, placing the CWA largely in the right exit region of the upper-level jet, where subsidence is favored. The strong jet is favored to develop as a trough over southern Canada strengthens, resulting in a potent 500mb shortwave racing across the Northern Plains into Minnesota and portions of the Midwest. A 115-120kt jet is expected with this shortwave over South Dakota, with 60-70kts expected overhead. Looking down at 700mb, another Canada shortwave trough is expected to rapidly develop and strengthen as is pushes into eastern Montana, moving east-southeast across North and South Dakota. This low is anticipated to rapidly deepen from an open wave, 284m trough over southern Canada to a 273m closed over over northern Wisconsin by early Friday morning, putting the low over North Dakota as the rapid deepening begins. A potent 80-90kt 700mb jet is expected to develop to the southwest of the low across northern South Dakota, resulting in an 80-85kt jet across the Laramie Range around 18Z Thursday, with jet around 70kts starting 12Z Thursday morning. Looking further down at the surface, a similar story unfolds. The surface low starts over far southwestern Alberta Providence in Canada, nearly in eastern British Columbia, forecast to be around 1004mb around 06Z Thursday morning. By 12Z Thursday morning, the surface low has moved easterly into southwestern Saskatchewan Province Canada and is forecast to deep to around 998mb. Concurrently, at 12Z Thursday morning, the 700mb jet is peaking across Montana around 85-90kts. By 18Z Thursday morning, the surface low is expected to be over far northwestern North Dakota and is forecast to deepen to about 993mb, at which point the 700mb jet associated with the low is around 80-85kts. By 00Z Friday, the low is forecast to be over eastern North Dakota around 989mb and over Minnesota around 990mb by 06Z Friday. At this time, this low is not anticipated to "bomb out", or drop 24mb in 24 hours, however, it will still be quite strong and very impactful across southeast Wyoming.

Now, focusing on southeast Wyoming and western Nebraska, the 700mb jet is progged to be around 60-65kts at 09Z Thursday morning with downward omega values across the CWA starting to drop. This jet is currently forecast to strengthen to 70-75kts by 12Z Thursday morning as the surface low rapidly intensifying across the Northern Plains. By 18Z Thursday afternoon, the 700mb jet over the CWA is forecast to peak at 80-85kts, with the GFS suggesting surface sustained flow of around 45-50kts east of the Laramie Range. Usually, something like this may draw some caution as it is still several days out and some of these numbers are quite ridiculous. However, even the ECMWF is similar at this time, with a 700mb jet around 60-65kts and surface sustained flow around 30-35kts. With the larger grid spacing of the ECMWF, it is entirely possible that some of the highest values are being smooth out. The GFS has also been suggesting a very strong winds even Thursday/Friday for about a week now and has maintained strength, if not strengthened slight, further increasing confidence in the system as a whole. Taking a look at surface pressure gradients across the Laramie Range, at the event peak, around 18Z Thursday afternoon, surface pressure gradients across the Laramie Range are at about 5-6mb and 4-5mb across the Arlington wind prone area, further suggesting very strong winds at this time. Additionally, surface pressure gradients between 6 and 7mb is modeled across the I-80 Summit and Foothills, which is extremely high and not a "typical" number for "typical" wind events. Peaking at the GFS Omega fields, they are, un-surprisinly, maxed out along the Laramie Range, suggesting very strong downward acceleration as well. NAEFS Mean 700mb Zonal Wind Speed climatology is Maxed out on the percentile, suggesting a very uncommon event for this time of year. Craig to Casper gradients are well above 75m for the duration of this event. In-house random forest guidance is nearly off the charts, with a probability of high winds at around 90% for Arlington, and 80-85% for Bordeaux, the Summit, and Foothills. Even Cheyenne is high, around 50% probability, when we usually look for around 25% due to the lower number of model training cases for Cheyenne. So, overall, this looks to be an extremely impactful event across southeast Wyoming, with some locations likely gusting 90+mph or higher with this level of setup. Cheyenne itself could easily see wind gusts over 75mph, if not higher, while the wind prones may be at that 90+mph range, with 100mph gusts not impossible to see. This event will continue to be monitored over the next several forecast updates, but High Wind Headlines could be issued as early as Tuesday. This could be a particularly dangerous setup for the region, especially with afternoon humidity expected to be quite low.

The last topic for this discussion will be the ongoing fire weather concerns across the region. Today, a Red Flag Warning is in effect for much of southeast Wyoming and western Nebraska as afternoon humidity values are expected to dry out into the 13-20% range with winds potentially gusting 35 to 55mph, depending on location. A brief break in fire weather concerns is expected Tuesday as the cold front pushes through and precipitation chances return. However, elevated conditions are still expected. Unfortunately, relative humidity values bottoming out in the 15-25% range is expected daily from Wednesday through Sunday. Should these humidity values continue to drop, a very dangerous situation could unfold for Thursday with the high end high wind event potential. This is not set in stone yet, but with downslope ongoing leading up to Thursday, it is not entirely possible for a very dangerous fire weather day to shape up on Thursday as well. More details on this in the days to come.

LONG TERM /FRIDAY THROUGH SUNDAY/

Issued at 318 AM MDT Mon Mar 9 2026

Northwest upper-level flow will slowly transition to more zonal flow Friday into Saturday morning ahead of an incoming trough Saturday evening into the morning hours Sunday. This upper-level trough will bring widespread precipitation chances back to the region for Saturday through Sunday, as northwest flow returns late Sunday night. Despite this trough moving in and precipitation returning, there appears to be no end in sight for high wind potential across southeast Wyoming. 700mb flow looks to remain very elevated through the weekend and into the start of the work week. Therefore, this windy pattern is not expected to go anywhere anytime soon. Temperatures will remain warm through the end of the week and into the weekend with daily highs in the 60s and 70s Friday and Saturday, with a cooler day expected Sunday as the upper-level trough funnels cooler air back into the region.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1100 AM MDT Mon Mar 9 2026

VFR conditions will dominate at all terminals this afternoon. Expect gusty westerly winds at LAR and RWL with winds increasing at CDR and BFF as well. Overnight, winds will relax but fast flow aloft will result in wind shear at LAR. VFR expected in the morning on Tuesday at all terminals with lowering ceiling heights starting around 18z in the NE panhandle terminals.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 6 PM MDT this evening for WYZ417-418- 430>433. High Wind Warning until 6 PM MDT this evening for WYZ101-106- 110-116-117. NE...Red Flag Warning until 6 PM MDT this evening for NEZ434>437.