textproduct: Salt Lake City

KEY MESSAGES, Issued 130 PM MDT Mon Sep 21 2026

- Moisture is pushing into southwestern Utah and will continue to gradually shift north and east with convection developing across central and northern Utah on Tuesday.

- Moisture remains elevated across the Four Corners through the week which will keep diurnal convection possible across southeastern Utah with dry conditions elsewhere in Utah.

DISCUSSION, Issued 130 PM MDT Mon Sep 21 2026

Moisture is starting to push into the southwestern portions of Utah with reflectivity on radar, however this rain is struggling to make it to the surface. RH across these areas are between 20% (lower elevation) up to 60% across the higher elevations. It will take a bit for the PBL to moisten, especially given the light rainfall rates. This activity is thanks to an upper level low that is currently centered over central California. This low will continue to move east with precipitation developing across eastern Nevada and western Utah this afternoon and evening.

This activity shifts into central and northern Utah on Tuesday with morning showers transitioning to afternoon thunderstorms. There will be plenty of shear (40+ kts) and steep lapse rates, although the CAPE will be marginal. This will favor quasi-linear storms that will be capable of producing gusty winds for areas near and east of the Wasatch and in Castle country. The storm motion with these will be rather fast, so that will limit the threat of any flash flooding to areas that are highly sensitive or areas where training thunderstorms occur.

This low pushes out of the area by Wednesday with a return to near seasonal temperatures and dry/stable conditions. The one exception will be across eastern and southeastern Utah as moisture remains elevated.

AVIATION

KSLC...Light northwesterly winds transition to southeasterly after 04z. Moisture increasing from the south will yield increasing clouds overnight with a 30% chance for showers to impact the terminal between 06-12z, with minimal operational impacts outside of variable winds. Additional shower activity is possible through the afternoon before chances for thunderstorms increase after 20z. Storms tomorrow afternoon will be capable of producing heavy rainfall and gusty and erratic outflow winds in excess of 35 kts.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions prevail overall for all regional terminals into Tuesday morning. Winds remain generally light and diurnally driven across northern Utah into Tuesday, while gusty southwesterly winds develop across southwest Utah Tuesday afternoon. Shower activity currently ongoing across southwest Utah will continue to spread northward through the evening and overnight, with showers impacting most northern Utah and southwest Wyoming terminals through Tuesday afternoon. Thunderstorms are expected to develop mainly across the northeastern portion of the airspace after roughly 20-21z, with potential to produce gusty and erratic outflow winds in excess of 40 kts and heavy rainfall that could drop VIS to MVFR/IFR at times.

FIRE WEATHER, Issued 130 PM MDT Mon Sep 21 2026

An area of low pressure is moving into the Great Basin. This is bringing an increase in cloud cover and showers to southwestern Utah. This activity will gradually shift north and east overnight with showers and thunderstorms developing across central and northern Utah on Tuesday. These storms on Tuesday will be capable of producing gusty and erratic winds along with frequent lightning, small hail, and brief heavy rain.

This activity moves out of Utah on Wednesday, but moisture will remain elevated across the Four Corners with diurnal convection possible across southeastern portions of Utah, but confidence in details remain low on these storms. The heaviest precipitation looks to remain across New Mexico and Colorado. Otherwise, winds will remain light and diurnally driven through the week with near normal temperatures.

SLC WATCHES/WARNINGS/ADVISORIES

UT...None. WY...None.