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.

- There is a Marginal Risk (Level 1 of 5) for severe weather Wednesday afternoon. The primary concerns will be damaging winds gusts caused by microbursts.

- The potential for high winds will return Wednesday afternoon into Thursday. This may event spread outside of the wind prone areas. A High Wind Watch has been issued for Wednesday afternoon through Thursday evening.

- 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 316 PM MDT Tue Apr 21 2026

The apex of the upper level ridging is just about centered over the Intermountain West. This ridging has help facilitate our mostly clear skies and drier air being pumped towards the surface. Looking across the Southeast Wyoming and Nebraska Panhandle area winds remain rather light with RH values being around 15 percent or less across the forecast area. As this ridge pushes off this evening an upper level trough will slowly push eastward from the Pacific Northwest and along the Canadian border. The pressure gradient is expected to increase as the trough pushes into the region as well as the dry line moving through. High winds look to start Wednesday morning and last through the evening Thursday. WInds in and along the wind prones look to possibly reach up to 80 mph as the 700mb jet increases to around 70 to 75 knots late Wednesday night into early Thursday morning. With the increasing downsloping winds Wednesday afternoon into Thursday, its questionable as to whether the dryline will have any moisture to lift considering the RH values being so low. If any showers do develop along the dryline then the highest threat would most likely be a dry microburst type setup where precipitation falls out of the cloud and evaporates before hitting the ground, however the weight and pressure displaced by the precipitation is still moving towards the ground causing and increase in wind gusts in all directions from the center point of where this column of weight and pressure impacts the ground. The high winds will continue into Thursday as the upper level trough continues to push through the Intermountain West and into the Northern Plains. There is a little bit of moisture being advected into the region along the trough axis as it pushes eastward. The highest chance for any measurable precipitation is in the mountains and lower elevations of Carbon county. The dry layer near the surface will be reinforced by the high winds east and along the I-25 corridor thus limiting the amount of any measurable precipitation hitting the ground in the lower elevations. As the high winds start to die down Thursday afternoon the precipitation chances will start to increase for the lower elevations east of I-25. Even though most of the forcing looks to be contained in the Dakota's, there are a couple vort maxes that lagged behind the main trough and increase the amount of synoptic forcing for our area. By Thursday evening the High winds should be done but we will have lingering strong gusts along I-80 and in our wind prone areas. Overnight Thursday, another shortwave will push into the Intermountain West giving greater precipitation chances across the forecast area moving into Friday morning.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 316 PM MDT Tue Apr 21 2026

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 /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1122 AM MDT Tue Apr 21 2026

Minimal aviation concerns as VFR conditions will prevail across all terminals for the duration of this TAF period. Gusty winds of up to 20 knots will impact the southeast Wyoming sites through 13Z Wednesday while the Nebraska terminals will see winds generally less then 12 knots. Winds will once again ramp up, first for KRWL around 13Z then spread east to KCYS by 16Z Wednesday, KBFF and KCDR will not be immune as they will too see their winds increase. So, expect gusts to increase during this timeframe into the 20 to 40 knot range, strongest at KRWL and KLAR.

CYS WATCHES/WARNINGS/ADVISORIES

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