textproduct: Western and Central Wyoming

KEY MESSAGES

- One more day of isolated showers and thunderstorms today, with temperatures a few degrees warmer than yesterday.

- Very hot temperatures return this weekend, many lower elevation sites having highs over 100. Some all time record high August temperatures may be set, especially on Sunday.

- Elevated to critical fire weather is likely this weekend into early next week, with Sunday and Monday looking like the days of most concern.

- A cold front will bring some relief from the hot temperatures early next week, mainly across northern and central Wyoming.

DISCUSSION

Issued at 158 AM MDT Fri Jul 31 2026

We have finally reached the end of July. And, like many of the past months in the past year, it has been a very warm one. Several of our climate sites are having their warmest July on record and many others are in the top 5. And this looks to continue into the weekend. And then, we may finally get some relief from the record warmth we have been experiencing.

It is generally more of the same today. It will be another very warm to hot day today, with temperatures a few degrees warmer than yesterday. Precipitable water values also drop another 10 to 20 percent today, finally getting back to near climatological averages. However, there is still just enough low and mid level moisture for some isolated showers and storms. As for where, the models continue to be on the struggle bus when it comes to where they will form. So, for now I have just gone with a broad area of slight POPS across most of the area, similar to the Storm Prediction Center outlook. The chance at most spots is less than 1 out of 5 though and most areas will not see one. The main threat from any storm would be strong wind gusts given the large dew point depressions. And this should be another show where most showers and storms should end by sunset with all showers done by midnight.

The ridge builds northward over Wyoming over the weekend. This will have two impacts. One, with the warming aloft and much drier air, the chance of convection will be almost zero. It will also warm quite a bit, with 700 millibar temperatures climbing as high as 20 to 21 degrees celsius. This should push high temperatures in locations below 7000 feet into the 90s, with areas below 5000 feet likely seeing highs into the triple digits. The peak of the heat still looks to be on Sunday. The reason for this will be a southwesterly, downsloping breeze that will develop ahead of an cold front dropping into Montana. This should add a few degrees to the temperatures in the lower elevations, with most locations below 5500 feet having at least a 3 in 5 chance of high temperatures of 100 or higher. The center of the heat looks to be in central Wyoming, where the Big Horn Basin from Basin to Thermopolis as well as the Wind River Basin below 5000 feet have a 1 in 2 chance of high temperatures of 105 or higher. This is the day we could see some all time record high temperatures for August. For some locations, this could be the third time this calendar year (they also occurred in March and July, as well as December of last year). As for highlights, we elected to go with heat advisories rather than excessive heat warnings. Why? For one, the really hot temperatures should only last two days, not four like back in July. In addition, the nights are now getting longer so we have a longer period to cool off at night. And relative humidity will be very low, as low as 5 percent. And this lowers the heat index. However, this will lead to another possible hazard.

And that hazard is elevated to critical fire weather. Elevated fire weather is likely on Saturday with the low humidity. However, wind is not expected to be strong and should remain below critical levels. It will be a different story on Sunday as the cold front approaches and tightens the pressure gradient. It is a bit lighter than yesterday, but still has a greater than 1 in 2 chance of gusts over 25 mph over portions of the area. We will hold off for now since there is still time, but future shifts may have to issue Fire Weather Watches starting on Sunday afternoon.

The aforementioned cold front drops through the area Sunday night and Monday, although it will be a slow passage. Temperatures will cool East of the Divide on Monday anywhere from 10 to 20 degrees, making for a nice, refreshing change from the recent hot weather. Southern Wyoming will likely see one more hot day before the front sips through Monday night. There is very little moisture with it though, so the chance of any showers is basically zero. And with the poor humidity recovery and gusty wind around the front, there will likely be another day of elevated to critical fire weather, so any highlights may end up being multi-day warnings.

Tuesday may should end up being the coolest and most comfortable day, possibly a taste of September. Many areas have at least a 1 in 2 chance of high temperatures under 85 degrees, with the warmest temperatures in southern Wyoming, where the front will likely wash out. The GFS MOS has a high temperature of 65 in Cody on Tuesday. This looks way too cool given the early August sun angle though. Following this, we should see a gradual warming trend, although record warm temperatures look unlikely the rest of next week. It also looks rather dry, with any deeper moisture likely remaining south of Wyoming. So, any chances of precipitation look slim for much of next week.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1104 PM MDT Thu Jul 30 2026

To start the period a few showers may linger mainly across western WY but overall terminals will see dry conditions with decreasing clouds overnight. VFR conditions will prevail across all terminals through the TAF period. Winds will remain light through much of the first half of the period at around 5 to 10 knots. Showers and thunderstorms will be possible once again starting shortly after 18Z Friday. Coverage is forecast to be very limited with most terminals likely to remain dry. PROB30 groups remain at KBPI, KPNA, KJAC, KLND, KCOD, and KCPR but that may change as confidence continues to decrease. If any storms do develop Friday afternoon the most likely impacts would be lightning and gusty outflow winds in excess of 35 knots. A brief period of MVFR conditions cannot be ruled out especially if any storms move overhead a terminal. Precipitation is expected to dissipate shortly after 00Z Saturday with all terminals remaining dry into the end of the TAF period. Mountain obscuration will be possible mainly in association with developing showers and storms during the afternoon/evening Friday.

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

RIW WATCHES/WARNINGS/ADVISORIES

Heat Advisory from noon Saturday to 10 PM MDT Sunday for WYZ003>006-010-011-013-016>020-023-025>030.