textproduct: Cheyenne

KEY MESSAGES

- Warmer this weekend with temperatures around 5 to 10 degrees above normal. Chance for Thunderstorms on Sunday as the next Pacific storm system moves onshore.

- A strong Pacific storm system will bring scattered showers and storms along with seasonably cool temperatures for the start to middle of next week, with a slow warming trend into the later part of the week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 115 PM MDT Sat Sep 26 2026

Conditions remain mostly quiet today under drier air across the CWA. That being said, there is some meager moisture present along with upslope flow across the higher terrain of the region, and high resolution guidance does try to produce some sort of, albeit weak, echoes for the area. A small thunderstorm did form just south of the Wyoming border and quickly fell apart, and that's what the expectation will be moving into the rest of the afternoon and evening as we may see some weak precipitation pop up and then fall apart as quickly as it came, mostly for areas along and west of I-25. Otherwise we continue to see some breezy conditions but nothing too unusual for this region under mostly fair skies.

On Sunday expect a similar setup in regards to temperatures as highs once again sit around 7 to 10 degrees above normal with widespread 70's to 80's. But as flow turns more southwesterly and brings low and mid-level moisture back to the region, we'll begin to see an increase in precipitation chances once again. We should see activity start to form off of the high terrain beginning during the mid to late afternoon timeframe and continue into the evening and overnight hours. While stronger and more favorable conditions for enhanced storms will sit just off to our east, a pocket of modest instability in the realm of 500-1000 J/kg alongside bulk shear values in the 30-40 knot range should be present across primarily the Nebraska Panhandle, and so as convection develops and propagates eastwards we may see a stronger storm or two for the area. Initial lapse rates will also be quite favorable, but with storms forming a bit on the later side it's likely they won't be able to take advantage of this during the evening. With PWAT values also on the rise thanks to this influx of moisture, peaking at around 0.75-1 inch for the day, some of this activity could produce very localized heavy rainfall, but storms are expected to remain isolated to scattered in nature and therefore a widespread precipitation event is not likely for the area. Chances may be better moving into the long term, but even that may be lessening with the newest model runs.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 115 PM MDT Sat Sep 26 2026

Unsettled weather will continue into the early part of the week ahead, but it is widespread beneficial rainfall is looking less likely. A split trough approaches the area on Monday, with the northern split passing to our north, and the southern split will be abandoned over the southwest to eventually absorb abundant tropical moisture associated with the remnants of Hurricane Polo. While precipitable water will be well above average Monday through early Wednesday, pushing around the 90th to 99th percentile of climatology, forcing for ascent looks weak at best, and instability remains unimpressive. The official forecast maintains modest PoPs (mostly 20 to 50%) through Monday and into Tuesday morning, as we can expect to see at least a few showers and storms around, but odds of significant rainfall are slim. Probabilities for total precipitation (through Tuesday) over 0.1" are lowest between I-25 and the WY/NE state-line, running around 20 to 50% here. Western Nebraska and the higher terrain of southern Wyoming both have higher odds, between about 50 and 80%. That being said, expect rainfall to be spotty, though the abundant atmospheric moisture will support the potential for highly localized heavy rainfall. A cool front moving through the area will knock down temperatures for Monday, with Tuesday looking like the coolest day.

For the middle of the week, the most likely scenario puts our area just outside of the region of precipitation associated with a soggy closed upper level low to our south. Ensembles are still all over the place in terms of the location of this low pressure system as it ejects eastward into the plains Wednesday into Thursday, but only the far northern end of the envelope of solutions (10 to 20% probability) would bring any impact to our area. The vast majority of ensemble members keep all rainfall with this system to our south, but it is still worth a mention as a shift north would lead to a vastly different outcome than currently shown in the official forecast for Wednesday and Thursday. Expect temperatures to warm up through the latter half of the week, with highs peaking above seasonal averages on Friday.

Another low-confidence storm system is showing up in a handful of ensemble members around next weekend. This will be another Pacific trough moving from the northwest. In about 20% of ensembles, this system is strong enough to knock temperatures enough to support a widespread freeze Sunday morning along with a quick shot of rain and snow showers to the area. However, the other ~80% have light showers and a modest cool down, with overall minimal impacts.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1120 AM MDT Sat Sep 26 2026

VFR conditions expected for the forecast period. Mid-level cloud cover will increase this afternoon, especially in Wyoming as west to northwest winds gradually weaken. Winds will be variable at times late this afternoon into the early evening, especially in Wyoming where some high based showers will be affecting the wind. Not much more than a few sprinkles is anticipated. Winds will be generally light overnight before picking up again late morning Sunday.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.