textproduct: Western and Central Wyoming

KEY MESSAGES

- A prolonged period of unseasonable warm temperatures will begin today and persist through much of the upcoming week.

- Low humidity, warm temperatures and a gusty breeze for Monday have led to Red Flag Warnings and near critical fire weather conditions across portions of the state.

- Daily to possibly all time monthly high temperatures are possible Monday.

- Mainly dry conditions and above normal temperatures will continue through at least Friday.

UPDATE

Issued at 1136 AM MDT Sun Oct 4 2026

One thing to update regarding the near term forecast. Fire Weather Watches have been upgraded to Red Flag Warnings starting Monday at noon through 6PM MDT. This is due to confidence growing in min RH's hitting critical values, winds gusting above 25 mph, and unseasonably warm temperatures in the low to mid 80s. Other portions of the state are likely to near or meet elevated fire weather conditions as well during the afternoon and evening. Otherwise, not much else to update as warm near record breaking temperatures remain likely for Monday. Well above normal temperatures are forecast to prevail through the remainder of the week. A few very isolated virga showers cannot be ruled out over higher elevations and far southwestern WY on Monday afternoon/evening. However, little to no chances for precipitation are forecast through the rest of the week.

DISCUSSION

Issued at 1253 AM MDT Sun Oct 4 2026

This is around the time of year when those of us who have been in Wyoming for a while start thinking about when the first snow is going to fly. I can remember a few snowstorms before this date, including a few damaging ones. That makes days like this one even more precious. Today may be the perfect early autumn day. High pressure will be over the area today. The result will be a cool, crisp morning followed by a comfortably warm afternoon with lots of sunshine. Wind should also remain fairly light as well, especially by Wyoming standards. And, it falls on a weekend, so most people will get to experience it. Enjoy!

Things get a bit more active on Monday. A Pacific trough will begin to approach the area from the west. This will tighten the pressure gradient somewhat and bring a gusty breeze, especially to the favored southwest flow areas from east of Rock Springs through Casper. This area has at least a 3 out of 4 chance of wind gusts past 30 mph according to the NBM ensemble forecast, along with areas like the Upper Wind River Basin and the Lee of the Absarokas. With mean relative humidity on the NBM ensemble generally less than 15 percent in these areas, we hoisted Fire Weather Watches for this area from 12 pm to 6 pm Monday. However, elevated fire weather will be possible elsewhere. And, with the warming, downsloping flow, it will be an abnormally warm day for the fifth of October. Most locations East of the Divide under 6000 feet in elevation have at least a 3 out of 4 chance of high temperatures over 80 degrees. Most locations under 5000 feet have a 1 in 2 chance of highs of 85 degrees or higher. There will likely be some daily record high temperatures. A few locations could get close or possibly break all time monthly record high temperatures at well, which are generally in the mid to upper 90s.

The pressure gradient should relax somewhat on Tuesday, so the result will be less wind and as a result some improvement in fire conditions, This should allow for temperatures to be a bit cooler, but still well above average and possibly break some more daily records. The trough will be passing to the south on this day. There may be just enough moisture for a stray shower or thunderstorm in Sweetwater County in the afternoon, but the chance is less than 1 out of 8 so we left it out of the forecast for now.

Warm and dry weather should continue through the remainder of the workweek. The next chance for critical fire weather looks to be Friday as a shortwave trough moves through the area na could bring some gusty wind and low humidity. We may have a pattern change following this as the trough breaks down and a more potent Pacific system approaches from the west. It could arrive as early as Saturday, but experience tells me the models are usually too fast with Pacific systems this far out, so it is more likely for Sunday. This is not certain, but odds are increasing of seeing some cooler and possibly wetter weather for next weekend or early the following week.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 345 PM MDT Sun Oct 4 2026

VFR conditions for all TAF sites during the entirety of the period. Light winds towards sunset after 02Z due to radiational cooling through the overnight hours into Monday morning. Some passing high clouds for JAC/RKS overnight, and eastward by 17-19Z Monday. Winds increase as well during this time frame with daytime heating and mixing to the surface. Gusty winds up to 18kts, with CPR up to 25kts through the end of the period, not to diminish until the next TAF cycle towards sunset once again. Otherwise, no other weather elements are expected at this time.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts.

FIRE WEATHER

Issued at 1253 AM MDT Sun Oct 4 2026

Low humidity will be around today, but wind should remain light to moderate. A combination of humidity falling into the teens and a gusty southwesterly breeze will bring elevated to possibly critical fire weather Monday afternoon, with Sweetwater, Natrona and eastern Fremont Counties the area of greatest concern.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from noon to 6 PM MDT Monday for WYZ279-280- 289-300.