textproduct: Western and Central Wyoming

KEY MESSAGES

- Mainly dry and warmer today across the area. Elevated fire weather is likely this afternoon is southern Wyoming.

- Rather hot Thursday and Friday with widespread highs in the 90s. Any thunderstorms would be confined to in and near the mountains.

- Deeper monsoonal moisture returns for the weekend and much of next week, bringing an increased chance of daily showers and thunderstorms.

DISCUSSION

Issued at 1230 AM MDT Wed Aug 19 2026

We still have a few showers out there early this morning, but these should be gone by sunrise. It finally looks like we will get a break from the monsoon, but it is like a shark. It is only leaving for a brief interlude, it will be back for more, but there will be break.

The main concern the next few days looks like it will shift to more hot temperatures. A ridge across the desert southwest will slowly build to the north, and bring a gradual rise in temperatures over the next few days. The rise in temperatures begins today, with widespread mid to upper 80s across most of the lower elevations, with a few locations possibly touching 90. As for precipitation, we can't completely rule it out but the chance will be close to zero for 95 percent of the area. We did add some slight chance POPs across southern Lincoln and western Sweetwater Counties where just enough moisture may linger for an isolated shower. With the dry low levels, it would likely only be virga. But even here, the chance is only 1 out of 6. Normal to below normal precipitable water levels should keep the rest of the area rain free. There is one other concern. There will be a bit of breeze developing in southern zones, and relative humidity will be falling to around 15 percent. This raises some concern for fire weather. At this time, the chance of getting 3 hours of critical fire weather is less than 1 out of 3, so we will not issue any fire weather highlights. Elevated fire weather will be likely for a few hours this afternoon though.

As we head to Thursday and Friday, the main concern will be heat as 700 millibar temperatures approach 20 celsius in portions of the area. On Thursday. most of the population centers below 6000 feet will have at least a 1 in 2 chance of high temperatures over 90. Friday still looks like the hottest day, with locations below 6500 feet having at least a 3 out of 5 chance of high temperatures over 90. Areas below 5000 feet will have a 1 in 2 chance of high temperatures over 95. The good news is this will be Wyoming heat, meaning humidity will remain low, meaning it should not be dangerous heat. As for potential convection, chances will increase each day as monsoonal moisture begins to creep back in. However, as per the usual progression, it will be largely at the mid levels first. Through Friday, most convection would be confined to the mountains with nothing more than a 1 out of 3 chance in any particular spot. And with many of the showers, rain may not even reach the ground. As for fire weather concerns, wind should remain light to moderate so critical fire weather is not expected despite the low humidity.

We will should be back in the monsoonal pattern on Saturday as deeper moisture spreads back over the area. Precipitable waters have the potential to climb over 150 percent of normal starting on Saturday and continuing through much of next week. All areas will have a chance of showers and storms starting on Saturday. As for the most impacted areas, the majority of guidance favors the maximum impact in western Wyoming this weekend, but confidence on this is low. There will be the usual ebbs and flows in the coverage of convection into next week, and it is difficult to nail down details this far out as to what day will be the most active. As for temperatures, with more cloud cover temperatures should begin to cool starting Saturday. Overall though, temperatures should remain largely above average into next week. So after around a three day break, the monsoonal pattern of diurnal convection likely returns this weekend.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 400 AM MDT Wed Aug 19 2026

VFR conditions will dominate through 12Z Thursday. Terminals should not see any impact from convection with the chance of an afternoon shower less than 10 percent. There is a slightly higher chance of a shower in vicinity of KRKS with isolated convection over the Unitas, but even here the chance is only around 10 percent. Wind will be light to moderate for the most part, although gusts to around 20 knots will be possible at KRKS this afternoon before decreasing after sunset.

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 1230 AM MDT Wed Aug 19 2026

A combination of an afternoon breeze and humidity falling to around 15 percent across portions Unita, Sweetwater, Sublette and southern Lincoln Counties will bring elevated to near critical fire weather this afternoon. Although relative humidity will remain low through Friday, lighter wind should improve fire concerns somewhat.

RIW WATCHES/WARNINGS/ADVISORIES

None.