textproduct: Western and Central Wyoming

KEY MESSAGES

- A weak cold front will bring cooler temperatures into northern Wyoming tonight, bringing overnight low temperatures closer to normal in the 40s.

- More seasonable temperatures over the weekend with breezy winds across southern Wyoming. Skies will remain mostly clear, mostly clear skies expected. - A stronger and mainly dry cold front pushes through late Sunday that will bring cooler air to start the new work week Monday. Temperatures will fall to near freezing west of the Divide, and low 40s to the east.

UPDATE

Issued at 1245 PM MDT Fri Sep 11 2026

IR and radar continues to show clearing west to east across the CWA with the main finger of the PFJ well to the north on WV near the Canadian border. An approaching cold front over southern Montana will aid in not as warm temperatures this afternoon. FROPA by late afternoon for northern parts of the area to near sunset for the Wind River Basin to Natrona County before pushing south before midnight. Breezy westerly winds ahead of FROPA with northern flow behind it, being quite gusty up to 40 mph for areas of the northern Bighorn Basin to Johnson County. Some light showers possible (15-20%) for the northern Bighorns, but nothing of consequence. A seasonable weekend in terms of temperatures ahead of the next system and front Sunday. This will be mainly dry but with a more potent cold push dropping 10 to 15 degrees for morning lows and afternoon highs on Monday. Beyond that, not much to speak of with a relatively benign forecast going forward.

DISCUSSION

Issued at 158 AM MDT Fri Sep 11 2026

Moisture has finally arrived over the Cowboy State, ending this prolonged streak of critical fire weather conditions. Partly to mostly cloudy skies continue over the state this morning, scattering out by midday day. Isolated showers to the west of PIH and SLC will continue to track eastward this morning and move over far western portions of the forecast area around 10Z. Virga is likely from these showers, but amounts around 0.05" will be possible over the Tetons/Gros Ventres and toward Union/Togwotee Pass. These showers may cross the Divide and move over the Upper Green River Basin, after sunrise this morning, but will likely stay as virga. These showers are expected to end by 18Z, with dry conditions expected through the rest of the day. There is a 10% chance for virga showers over areas east of the Divide late in the afternoon as a cold front drops southward.

Widespread gusty winds will be the main concern again today, with west wind gusts of 25 to 35 mph occurring across the CWA this afternoon. The exception will be portions of the Bighorn Basin and the northern half of Johnson County. Northwest wind gusts up to 30 mph will occur in these areas as a cold front progresses southward through the afternoon. The front will pass through the Bighorn Basin and Johnson County by 00Z Saturday (6pm), quickly reaching the Casper area and Riverton between 01Z and 03Z, eventually becoming stationary along the Divide by 06Z. Temperatures will much cooler today, especially east of the Divide, running about 5 to 10 degrees cooler. This will apply to far northern portions, due to the proximity of the front.

Models have become aligned with the much talked about storm system for this weekend, with not much change from yesterday with the forecast track. The storm system is still forecasted to drop southward along the West Coast tonight into Saturday. The aforementioned cold front will gradually retreat northward Saturday afternoon, due to an increase in southwesterly winds. The front looks to get pushed into the Bighorn Basin and further north into Sheridan County through Saturday afternoon. Apart from isolated showers and thunderstorms over eastern portions of Sweetwater County Saturday afternoon, conditions are expected to remain dry. Precipitation chances continue to be pushed northward as the storm stays further north in MT. Little to no precipitation is now expected from this storm. The associated cold front will push through the Cowboy State Sunday night, clearing the forecast area by 12Z Monday. Sub-freezing temperatures will return to western portions Sunday night/Monday morning, with readings in the upper 30s to lower 40s elsewhere. Dry and cooler conditions will be in place Monday, with highs in the 60s to near 70 degrees across the area. Conditions will remain dry with seasonal temperatures Tuesday. A storm system may impact the region Wednesday, but confidence is low at this point as colder, Canadian airmasses begin to drop southward.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1050 PM MDT Fri Sep 11 2026

VFR conditions expected for most over the next 24 hours. A cold front has pushed southward east of the Continental Divide, and will bring breezy northeast winds to many locations in the basins of northern and central Wyoming. West of the Divide, westerly winds are weakening, and will become light overnight. Expect breezy west winds to redevelop Saturday afternoon, especially west of the Divide. Very little cloud cover to mention for most sites, with COD and CPR being exceptions. Both of theses sites could see brief scattered to broken MVFR cloud decks due to nearby light rainfall this evening, which had lead to a little moisture in the low levels of the atmosphere. Any low clouds near these sites are expected to quickly dissipate after sunrise.

RIW WATCHES/WARNINGS/ADVISORIES

None.