textproduct: Western and Central Wyoming

KEY MESSAGES

- Above normal temperatures today, with a mostly sunny sky.

- A weak weather system brings gusty winds to the area Tuesday morning through Tuesday evening. Gusts 20 to 30 mph will be common across the area, with wind prone areas having gusts up to 40 mph.

- Weak, very isolated (15%) showers are possible across Yellowstone and along the Montana/Wyoming border between 4am and 11am Tuesday. No impacts expected.

- Dry and mild weather continues through the rest of the week.

UPDATE

Issued at 1152 AM MST Mon Nov 9 2026

No major changes with this update, with a weak weather system bringing limited rain/snow chances to northern Wyoming and gusty winds for Tuesday. Have updated the minor precipitation chances tonight into tomorrow across far northern Wyoming with the latest hi- res guidance. Chances for an accumulations remains about 10 percent or lower for most, with the best odds (15-20%) for Yellowstone into the Cody foothills. Any precipitation would be little to nothing. Timing of these light showers occurs between about 4am and 11am. If anything, cloud cover will be around. Elsewhere, conditions remain dry with passing clouds.

DISCUSSION

Issued at 110 AM MST Mon Nov 9 2026

The weather patterns often remind may of my college work in meteorology many moons ago. Some of the courses, like map analysis, synoptic and mesoscale (the forecasting classes) as well as severe weather, were the exciting and interesting classes. Then we had courses like dynamics (I still have bad flashbacks about having to derive the equations almost 30 years later) that are, no offense to my former professors, rather boring and tedious. The forecast over the next five days or so, falls into the latter, rather boring.

Things today look fairly similar to yesterday with a flat ridging / zonal flow over the area. This means temperatures fairly similar to yesterday (8 to 12 degrees), cloud cover similar to yesterday (passing areas of mid to high clouds) and (noticing a pattern), wind fairly similar to yesterday (light to moderate for most, but gusty in westerly flow locations, like the lee of the Absarokas and Casper). Humidity does look a bit higher than yesterday though, so fire concerns should be a bit less (there had to be one difference).

The one bit of rather measured excitement will occur late tonight into tomorrow as a weak shortwave brushes by to the north. There will be two main impacts. One will be the chance, although a small one for some showers across northern Wyoming. The chance outside of the models is very small through, generally less than 1 out of 5 with any amounts rather negligible. But even in the mountains, the chance of greater than a tenth of an inch of precipitation is less than 1 out of 10. All showers should be east of the area by mid afternoon. The other impact will be for gusty wind across the area. The 700 millibar winds only max out at around 30 to 35 knots, so high wind is not expected. However, much of the area has at least a 3 out of 5 chance of wind gusts on Tuesday, with the strongest gusts in the afternoon with wave passage and period of maximum diurnal mixing. Wind should decrease at night as the wave moves away and the atmosphere decouples.

We then enter a boring period as strong ridging moves over the area starting Wednesday and lasting at least into Friday. This means a few pleasant days with sunshine and mild temperatures. Wind should be light through most of the period for most locations. The exception will be in the favored southwest flow locations, which may see a gusty wind as the pressure gradient tightens ahead of the next potential weather maker.

And notice the word potential (aren't modifiers wonderful). Because, as would be expected this far out, there is a fair amount of uncertainty with the details. Different ensemble members are all over the place, as well as the deterministic models. All guidance has the ridge breaking down, although at different speeds. For example, the European is faster and shows the Pacific system being a little stronger, with the associated trough becoming negatively tilted and bring a bit more wrap around moisture to northern Wyoming. The GFS is much slower, holding the ridge and not bringing the system in until Sunday night or Monday. The trough is also much weaker and having more of a west / southwesterly flow upslope - downslope pattern with the precipitation, with most falling in the western mountains. It also means a longer period of above normal temperatures and gusty southwest wind; with potentially elevated fire weather to portions of central Wyoming. The European does tend to be too fast with Pacific systems this far out, so the greater chance (about a 2 out of 3 chance) is for a slower arrival of the precipitation. Stay tuned as we get closer to next weekend as the details come into better focus.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1032 AM MST Mon Nov 9 2026

VFR conditions are expected across all terminals through the TAF period as dry conditions linger along with lighter winds. The exception being KJAC and KCPR which will gust up to 15-20kts through sunset and return to light winds overnight. KJAC will also not see wind shifts overnight as 190-220 degree winds hold through tomorrow morning. A weak disturbance will then move in tomorrow bringing breezier winds across all sites, gusting up to 20kts after 17-18z, while KRIW and KLND see gusts trend lighter. A few high level clouds are expected above 20000ft through mid morning tomorrow, clearing out to clear skies for tomorrow afternoon.

RIW WATCHES/WARNINGS/ADVISORIES

None.