textproduct: Cheyenne

KEY MESSAGES

- A Red Flag Warning remains in effect for all areas east of the Laramie Range until Wednesday evening as critical fire conditions are expected.

- Strong wind gusts caused by downburst winds are possible Wednesday afternoon, though the Marginal Risk has moved east of the CWA.

- A widespread, high wind event looks likely Wednesday afternoon through Thursday evening for most of southeast Wyoming. All High Wind Watches in southeast Wyoming have been upgraded to High Wind Warnings, while Watches remain in effect for western Nebraska.

- A cooler weather pattern with more frequent chances for precipitation will take over Thursday and last into early next week.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 225 AM MDT Wed Apr 22 2026

A tale of two worlds over the next couple of days as the upper-level ridge leading to warmth and fairly light winds shifts off to the east and a strong, upper-level trough moves in from the west. Strong southerly to southwesterly flow will develop aloft later this afternoon as the upper-level trough attempts to strengthen across Idaho. Strong 500mb vorticity advection will accompany this approaching trough, with multiple lobes of 500mb vorticity ejecting out ahead of the trough axis. 700mb flow will increase and turn southwesterly across western portions of the region this morning into the late morning and early afternoon hours as the 700mb low struggles to develop over northern Montana. The 700mb jet will increase to around 50kts by this afternoon, with modest to strong downward omegas suggesting by the GFS around the same time. Surface pressure gradients increase in the early afternoon hours, leading to a 4 to 5mb gradient across Carbon County. As a result, strong winds are expected to develop late this morning into the early afternoon for much of Carbon County and the Arlington/Elk Mountain wind prone zone. Similarly, along and east of the Laramie Range, very strong winds are anticipated to develop later this evening as the 700mb low continues to strengthen across northern Montana and a strong, westerly, 700mb jet develops across the Laramie Range. Surface pressure gradients increase significantly as a surface low riding the Canada Border deepens an drags a cold front through the area. A strong, Bora Event is anticipated to develop behind the cold front as surface pressure gradients remain highly elevated, the 700mb jet retains its strength, and downward omega values are progged to be maxed out along and east of the Laramie Range. As a result, all High Wind Watches for southeast Wyoming have been upgraded to High Wind Warnings. The strongest winds along and east of the Laramie Range are most likely to occur overnight tonight into the early morning hours on Thursday. Confidence remains low for the Nebraska Panhandle to see strong winds associated with this system, so High Wind Watches remain in place for southern portions of the Panhandle.

Temperatures today will be quite warm ahead of the cold front, in the 60s west of the Laramie Range and mid-70s to upper-80s east. This cold front is expected to be quite strong, so temperatures will tank quickly behind the system for locations not seeing downslope warming associated with the Bora Event across the Laramie Range. Precipitation will be isolated at best across the region this afternoon into the overnight hours, with the higher terrain out west most likely see accumulating precipitation in the form of snow. The western Nebraska Panhandle has since been moved out of the Marginal Risk for severe weather, but an isolated thunderstorm cannot be ruled out, especially across Dawes and Box Butte counties where an isolated pocket of 200-500 J/kg of CAPE may develop. Unfortunately, very dry surface conditions will continue this afternoon, so any precipitation that falls out of showers in the Panhandle will likely evaporate before reaching the ground. Therefore, there is an increased threat for isolated, downburst winds with any shower or storm that develops across the Panhandle today, but these are not expected to be widespread in nature. Additionally, with very dry conditions and increasing winds through the afternoon hours, Red Flag Warnings will continue today with extreme fire danger across much of the area east of the Laramie Range. Fire concerns decrease behind the cold front as temperatures cool rapidly and a touch more moisture pushes into the region.

Thursday will feature the upper-level trough slowly rotating across the region, though unfavorable 500mb vorticity advection looks to limit the speed as which this trough moves out of the area. The 500mb vorticity profile looks a litter messy, for lack of a better term, leading to a much slowly progression of the upper-level trough as unorganized vorticity advection occurs. Therefore, cool temperatures are anticipated to continue for the next several days as the upper-level trough slowly advects out of the area. Luckily, the position of the upper-level trough will continue to support synoptic ascent, leading to continued precipitation chances throughout the day Thursday. The best of the precipitation looks to remain confined to Montana as the surface low meanders slightly further north into southern Canada. However, a secondary cold front pushes through the area Thursday evening, leading to a reinforcement of cooler air aloft and continued precipitation chances. Snowfall totals from Wednesday evening through Friday morning will be low, likely in the Trace to half an inch category outside of the mountains. Rain will be the primary precipitation type before the cooler, reinforcing cold air moves into the region. Given the very warm temperatures recently, it will take a long time for any snow to start accumulating, so significant accumulations are not anticipated at this time. Strong winds slowly come to an end through Thursday evening, before another shot of elevated winds move into western portions of the region for Friday.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 225 AM MDT Wed Apr 22 2026

No major changes with the forecast update. Please see the previous long term discussion...

As we head into the long term period, one thing will be very clear, the air will feel a little crisper on your skin. Expect temperatures to be and remain near normal, believe it or not, with highs topping out in the 50s across southeast Wyoming and low to upper 60s in the Nebraska Panhandle. Not only this, but we will be in an active pattern, so precipitation chances will be elevated compared to what we've been seeing as of late. Why, well, more on that in a bit. Hopefully this increased chance of precipitation will make a dent in the extreme drought (U.S. Drought Monitor) we are in and cut down our fire weather threat. So, what is different this time around? Well, the main player in this forecast period will be a robust upper- level low that becomes parked over Saskatchewan with a trough stretching south into our region. This will allow vort maxes, pulses of energy, to feed into our CWA and kick start that increased precipitation chance. As we progress into and through the weekend, this upper-level low will remain quasi-stationary over Saskatchewan through at least Monday. Thereafter, it will move off to the east and weaken as a weak transient ridge builds across our CWA, drying us out briefly.

What are the probabilities of seeing at least 0.10" of precipitation? Well, there will be a weak system that slides in Friday and ensemble guidance has probs remaining relatively low across the CWA. However, there will be another system over the weekend into early next week that will give us a better chance. Probs with this one are in the 60 to 80% range of seeing 0.10" of liquid precipitation. Most locations will see primarily rain, but in the higher elevations this rain may mix with snow or remain all snow, with amounts still needing a bit of ironing out. Winds in the long term will not be much of a concern with meager mid-level support. Friday morning has our best chances with a 50 knot 700MB jet sliding in. Per GFS, omega will be lacking so these winds may not mix down to the surface.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 508 AM MDT Wed Apr 22 2026

Increasing winds expected late this morning into the afternoon hours for all terminals. Strongest winds are expected at KCYS, KLAR, and KRWL where gusts up to and over 50kts will be possible. Wind shift expected later this afternoon between about 21 and 00Z, with winds continuing to increase. Isolated, showers may develop near KCDR this afternoon, though confidence is low. If showers do develop, gusty and erratic winds will be possible with all showers that form. Winds continue to increase overnight tonight, with winds not decreasing until late Thursday evening.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 8 PM MDT this evening for WYZ417-418- 430>433. High Wind Warning from noon today to 3 PM MDT Thursday for WYZ101. High Wind Warning from 9 AM this morning to 3 PM MDT Thursday for WYZ104-109-111-113. High Wind Warning from 3 PM this afternoon to 6 PM MDT Thursday for WYZ106-116>118. High Wind Warning from 6 PM this evening to 6 PM MDT Thursday for WYZ107-108-115-119. High Wind Warning from 9 AM this morning to 6 PM MDT Thursday for WYZ110. NE...Red Flag Warning until 8 PM MDT this evening for NEZ434>437. High Wind Watch from Thursday morning through Thursday afternoon for NEZ003-019>021-054-055-096.