textproduct: Cheyenne

KEY MESSAGES

- Above average temperatures with dry and breezy conditions lead to a Fire Weather Watch in the Nebraska Panhandle on Saturday.

- A pattern change will bring a gradual cool down and increased chances for precipitation Sunday through much of next week.

SHORT TERM /THROUGH SUNDAY/

Issued at 306 PM MDT Fri Oct 9 2026

The short term forecast when making headline decisions has a lot of uncertainty because our forecast area is on the border of some critical weather elements. At the upper levels there are two dynamic low pressure systems pushing into the western coastal region. One is hitting us from the Pacific Northwest and the other is Hurricane Rachel. These low pressure systems will collide against our weak upper level ridge. This ridge will slowly push east creating a sort of division between our Southeast WY and Nebraska Panhandle forecast area sections. These systems will be funneling Pacific moisture into the Rocky mountains while tightening the pressure gradient allowing for gusty winds today and tomorrow. The mountains on the western side of Wyoming will absorb most of the moisture flow but there looks to be enough to produce some showers for our area west of I- 25. For areas east of I-25 in Southeast Wyoming it looks to be more microburst-virga regime. The dry airmass underneath the ridge will still reside over the panhandle and possibly Torrington for lower RH values and lighter winds. Gusty winds of at least 35-40 mph look to be likely across Southeast Wyoming while the Panhandle will be a little bit less with max wind gusts up to 25 mph. THerefore, A fire weather watch was issued for the Nebraska Panhandle and a portion of Goshen county. There is some uncertainty if the wind gusts will last the 3 hour time requirement for a red flag warning so that why the watch was issued instead. Saturday night the stronger winds will reach portions of the Nebraska Panhandle but by the time they do our RH recovery will be way above any fire weather threshold. So its a little bit of a tricky forecast for our area since we are right on the line for some things. Temperatures will also decrease as the moisture and showers moves across Southeast Wyoming ranging between 70 and 80 degrees while the Panhandle will be fairly warm with temperatures between 80 and 90 degrees.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Issued at 435 PM MDT Fri Oct 9 2026

The stagnant warm and dry weather pattern will finally break on Sunday as a powerful upper level low approaches the area from the west. A complex interaction will take place between the approaching trough, which will be in the process of splitting, and the remnant moisture/circulation of former Hurricane Rachel. The best synoptic forcing for consistent rainfall will stall to our west, which has resulted in a drier trend for much of our area in the last few forecast cycles. That being said, we will still have abundant moisture in place over the area. Ensemble mean precipitable water is around 3 to 4 standard deviations above the mean, near climatological maximums. Still, with weak forcing and unimpressive instability, precipitation expectations are on the low side. Rawlins and Douglas, which will be closest to the strongest forcing, have ensemble median QPF values only around 0.1 to 0.2" for the first phase of this event which will last through Monday morning. Further east, expect a few showers Sunday into Sunday night, but precipitation should be fairly limited. In addition to the showers, gusty southwest winds will continue along and west of the Laramie range. Probabilities for high winds peak around 30% in the wind prone areas on Monday morning, but expect fairly consistent gusty winds all the way through at least Monday.

Meanwhile, the northern branch of the split trough will drop a surface high pressure down from the north. The surface front will push into the area Sunday, but stall around the Laramie range. As a result, we can expect a significant cool down for our northern areas, solidly behind the front, with Sunday's highs around 15 degrees cooler than Saturday. The front will struggle to reach the I- 80 corridor, so 24-hour temperature drops in this area will be only around 5 degrees or so with highs remaining well above average. The upper level low digging into the west coast will help amplify the downstream ridge over the central CONUS on Monday, helping to push drier air a little further north into our area. Expect a bit more sunshine Monday with temperatures around 5 to 10F above seasonal norms. A few isolated showers will be possible, but once again, do not expect much rainfall.

Precipitation potential looks more promising during the middle part of the week. The now closed upper level low over the west coast will push northeastward and eject into the Plains mid-week. This will deliver two additional windows for precipitation, both of which look better (if you want rainfall) compared to the first phase on Sunday/Monday. The "dry" (relatively) slot moves out as another surge in southwest flow and mid to upper level moisture pushes precipitable water back to around the 97.5 percentile by the end of the day Tuesday. Look for scattered showers developing across the area Tuesday continuing into Wednesday, supported by potent isentropic lift ahead of the primary trough axis. There is a little bit of uncertainty concerning the timing of the trough axis, but expect this to push through sometime between Wednesday and Thursday morning. There is also potential for a back-edge round of precipitation behind the upper level low, forced by the development of a TROWAL. The question for this period of time is how quickly does the system eject, and does it merge back with the primary flow to our north before passing through our area. This will determine exactly how the back edge of precipitation develops, and the potential for high winds (more likely the faster the closed low rejoins the parent trough). Overall, the second and third phase of this event look more promising in ensemble QPF, but there are a lot of ways for these ingredients to fail to come together and cause our area to miss out on rainfall. Current ensemble median QPF is around 0.5 to 0.75" for most of the area, but changes are nearly guaranteed as we get closer to the event. Relatively few ensemble members (perhaps 25%) have enough cold air with this system to drop snow levels into populated areas of southeast Wyoming, but some light snow about 9000 ft in elevation appears likely. We will get a cool down with this system regardless of the precise outcome. The most likely scenario brings temperatures back to near seasonal norms on Tuesday and Wednesday, and then possibly below seasonal norms for Thursday and Friday. A freeze is likely (50 to 75% probability) for Douglas, Rawlins, and Laramie by Friday morning, and possible (20 to 50%) for remaining portions of the area.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 526 PM MDT Fri Oct 9 2026

VFR conditions will prevail through the TAF period, with gusty winds being the main hazard over the next 24 hours. Breezy WSW winds with peak gusts up to 35-40 knots are expected to persist through the overnight hours into tomorrow at KRWL, with the other sites experiencing a decrease in winds below 15 knots into the night. For tomorrow, expect an overall increase in clouds from southwest to northeast throughout the afternoon ahead of our next upper-level disturbance. Introduced a PROB30 group for -SHRA at KRWL after 21Z where shower coverage will be highest.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 7 PM MDT this evening for WYZ417>422- 425-427-432. Fire Weather Watch Saturday afternoon for WYZ433. NE...Red Flag Warning until 7 PM MDT this evening for NEZ434. Fire Weather Watch Saturday afternoon for NEZ434>437.