textproduct: Cheyenne

KEY MESSAGES

- Dry conditions expected through Friday alongside critical Fire Weather conditions.

- Moisture and cooler temperatures return for the weekend, with another shot of cooler air to start next week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 1219 AM MDT Thu Sep 10 2026

Transient ridging today continues to produce some of the driest conditions we've seen, with surface pressure gradients in the western half of our CWA promoting critical fire weather conditions from gusty winds. Looking at latest high resolution output, seeing enough concern of more widespread 20-40 mph wind gusts to expand the Red Flag Warnings across the region, including more of the mountains through the Laramie Summit area and into Platte and Goshen Counties. In fact, would not be surprising to see Red Flag conditions possibly expanding into Laramie County, but for now have left the Cheyenne zone out, but will pass along concerns to the incoming day shift. Outside of this critical fire weather environment, sensible weather concerns are nil during an otherwise benign weather day, with highs around 5 to 8 degrees above normal.

Friday we'll see increasing zonal flow with monsoonal moisture beginning to return, though we'll still remain notably dry overall. At the surface, a cold front should drop down from the north and fully pass across our region by Saturday morning. While the increased moisture may bring a chance at precipitation returning, inverted V profiles remain prevalent across the forecast area, meaning we should continue to primarily see gusty virga showers and perhaps some dry lightning. Gustier winds should shift further east, and with RH values remaining in the teens across far eastern Wyoming and the Nebraska Panhandle, it's very likely we'll need to continue Red Flag Warnings and extend them to the east for the day. Otherwise, temperatures largely similar to Thursday, still remaining several degrees above normal before the cold front drops us back down over the weekend.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 145 PM MDT Wed Sep 9 2026

A cold front should have made its way through the area overnight Friday. The timing is in fairly good agreement between global models with a five degree drop in the morning minimum temperatures compared to Friday. This will translate into a pleasant afternoon with highs in the upper 70s to low 80s. The northerly winds behind the front swap to southeasterly in the afternoon with the return flow. Aloft it is possible that a shortwave trough is passing through the area. This shortwave would provide a little more lift and moisture to perhaps kick off scattered showers and thunderstorms with IVT in the 90th percentile.

Sunday we should start to feel the effects of a new upper level system moving into the Pacific Northwest. Stronger return flow ahead of this system's passage would increase storm potential. Some machine learning models are depicting a risk area on and east of I- 25. Ensemble models have 75 percent of members having CAPE and shear values above climatological average and about 30-50 percent having values above the 90th percentile of climate. In other words the signal for severe weather is starting to show in guidance. A cold front associated with the Pacific system passes through sometime Sunday night into Monday morning.

Post front temperatures cool and a drying trend starts as a ridge builds up again. Return flow possible on Tuesday which could allow more diurnal shower and storm activity. The signal for another system at this range is murky. If no other system turns up in ensembles expect the ridging pattern to persist in the long term.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1131 AM MDT Thu Sep 10 2026

This afternoon, wind will become breezy over the WY terminals, weakening in the evening and overnight. Wind over the NE terminals will pick up this evening and into the morning hours, staying gusty through tomorrow afternoon. Sky conditions are expected to be SKC, with a FEW to SCT high level cloud decks moving in this afternoon and evening. Otherwise, VFR conditions are expected for this TAF period.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 8 PM MDT this evening for WYZ419>429- 432. NE...None.