textproduct: Salt Lake City

KEY MESSAGES

- Building high pressure will bring a steady warming trend in temperatures through Thursday across the south and through Friday across the north.

- Monsoon moisture will move back into Utah and southwest Wyoming late in the week, persisting through at least early next week. This will bring an increased threat of showers and thunderstorms capable of producing flash flooding.

DISCUSSION

High pressure centered over AZ this evening will shift east on Thursday before ending up over NM/west TX over the weekend where it is expected to remain in place into early next week. This shift will initially aid in a continued warming trend before bringing increased moisture into the area beginning during the Thursday/Friday timeframe. Current PWATs of around 0.8 inches is expected to increase to 1-1.1 inches across the area by Saturday afternoon.

Expect afternoon highs of near to above 100 degrees in many valleys on Thursday even as midlevel moisture starts to creep into southern Utah. On Friday, as the moisture starts to surge into southern and central Utah, temperatures there may begin to cool but continue to trend slightly warmer or at least remaining near persistence across northern Utah. This moisture, the initial surge being associated with a vort max lifting through the area, will then spread into northern Utah by Saturday, allowing for a cooling trend thereafter. HeatRisk is in the Red (Major) category across many valley areas on Thursday, then will become more confined to northern Utah for Friday. Heat Advisories are in effect for west- central through northwest Utah valleys as a result. The need for any Warnings is diminished due to acclimation to hot temperatures throughout the summer.

With the arrival of the moisture, expect increasing coverage of showers and thunderstorms along with increasing heavy rain potential into early next week. There is currently a Marginal Risk of Excessive Rainfall across southern Utah Thursday and Friday. This Marginal Risk will spread through the rest of the forecast area for Saturday and Sunday.

The high pressure looks to slowly start building westward again by the middle of next week. Depending on how for west the high center ends up (as there is still some model spread in this regard), the airmass may start to gradually dry for the second half of next week.

AVIATION...KSLC

The SLC terminal will see VFR conditions through the overnight hours with some high clouds. Light and variable winds will become prevailing southerly by 05Z and should shift to the northwest again between 18Z and 20Z.

REST OF UTAH AND SOUTHWEST WYOMING...The airspace will see VFR conditions with generally light and terrain driven winds through the overnight hours. Isolated showers and thunderstorms are expected to develop over eastern Utah tomorrow afternoon before dissipating tomorrow evening. Any storms that develop will be capable of producing gusty and erratic thunderstorms winds, lightning, and brief mountain obscurations.

FIRE WEATHER, Issued 131 PM MDT Wed Aug 19 2026

Strengthening high pressure will continue to bring a trend of warming and drying across Utah, with high temperatures in many lower lying valley areas reaching back into the triple digits. Alongside the heat, further drying is expected across Utah's West Desert on Thursday with humidity falling by another 5 percent. As such, isolated pockets of single digit humidity are expected in the West Desert on Thursday afternoon. On a positive note, winds will remain generally light and terrain driven through the heat and low relative humidity, keeping significant fire weather concerns low. High-based moisture will make a subtle increase on Thursday, bringing increased coverage of dry thunderstorms over Utah's high terrain. Still, coverage is expected to be isolated to widely scattered.

Moisture continues to increase through the late week and into the weekend, bringing increased coverage of showers and thunderstorms across Utah. With increasing lower level moisture, the potential for wetting rains from individual storms will greatly increase. In addition to the increasing chances for wetting rains, afternoon relative humidity will also significantly improve throughout the mountainous terrain while RH values in the lower elevation valleys of western and eastern Utah will struggle to rise out of the teens.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Heat Advisory from noon Thursday to 7 AM MDT Saturday for UTZ101>106.

Heat Advisory from noon Thursday to 7 AM MDT Friday for UTZ115- 116.

WY...None.