textproduct: Western and Central Wyoming

KEY MESSAGES

- Wildfire smoke remains present across Wyoming, especially the northern portions of the state through at least early Wednesday afternoon.

- Rain shower potential increases today and becomes more numerous across western and central Wyoming. Rain chances (50%-90%) become more widespread on Thursday with cooler temperatures and rain chances continuing into the weekend.

DISCUSSION

Issued at 150 AM MDT Wed Aug 12 2026

A pattern shift is currently underway that will lead to chances for precipitation each day through the rest of the week and through the weekend. This shift will also put an end to the latest heat wave with temperatures remaining at or slightly below normal through the weekend. The culprits for this cooler and wetter pattern will be a broad area of high pressure over the Deep South/Gulf Coast and a longwave trough over the West Coast. The Cowboy State will be sandwiched between these two features resulting in a moist southwesterly flow pattern. Embedded shortwaves will rotate northward over the region, bringing widespread chances for showers and thunderstorms across the CWA each day through Sunday. The threat for locally heavy rain will also return as monsoonal moisture will return as well. Precipitable water values of 0.75" to 1" will be in place across the region today and remain in place through the forecast period. Chances for precipitation will increase over western portions after sunrise this morning, spreading across areas east of the Divide through the rest of the morning and continue through the rest of the day. A separate wave of showers looks to move over Sweetwater County after 20Z. Most showers will be ending in the evening, with some lingering over the central basins through 08Z Thursday. Any thunderstorm is likely to be very isolated due to a lack of instability for the mostly cloudy/overcast skies. These clouds will also be the reason why temperatures will be 4 to 10 degrees cooler today. The hazy/smoky conditions will begin to thin today, with improving conditions expected by Thursday as the increased chances for precipitation allow the atmosphere to become more mixed. Additionally, the southwest flow aloft will cut off the source region of most of the smoke (the large fire complexes in OR/WA).

Showers and possible thunderstorms will return across areas west of the Divide by early Thursday afternoon and spread across the rest of the CWA through the rest of the day into the evening. There will still be a threat for locally heavy rain, with a higher focus over Johnson County and portions of Natrona County. This will be due to Gulf moisture advecting into the region, pushing PWAT values to 1.25" in this area. Strong thunderstorms are possible as well, with forecasted CAPE values of 1500 to 2000 J/kg and a lifted index of minus 4 to minus 6. However localized flash flooding will likely be the highest threat as bulk shear will only be up to 30kt. WPC Excessive Rain Outlook is also forecasting a Slight risk for this area for Thursday.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 450 AM MDT Wed Aug 12 2026

Light rain will continue to move over western portions of the forecast area from UT/ID this morning. The main impact will be wind gusts up to 25kt. Most terminals have at least a 30 percent chance of rain showers, and associated breezy winds, through the day today, with showers impacting KRKS by 20Z. Most activity is forecast to diminish by 01Z Thursday. A few rumbles of thunder cannot be completely ruled out later this afternoon. Although conditions are expected to remain largely VFR, a heavier rain shower could cause brief periods of MVFR visibilities and ceilings in addition to gusty 25 kt to 30 kt winds. Outside of any shower activity, winds are forecast to remain 12 kt or less at most terminals. Occasional gusts around 20 kt are possible at KRKS, KCPR, KRIW, and KBPI from outflow boundaries. Smoke is expected to continue across the state, especially in the area of KCOD and KWRL, through at least sunrise on Wednesday. However, visibilities are forecast to remain VFR.

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

RIW WATCHES/WARNINGS/ADVISORIES

Air Quality Alert until noon MDT today for WYZ001>011-019.