textproduct: Salt Lake City

KEY MESSAGES, Issued 1229 PM MDT Wed Oct 21 2026

- Widespread precipitation will bring an elevated and prolonged threat of flash flooding across southern and central Utah through Thursday. There is a Slight Risk of Excessive Rainfall (level 2 of 4) across southern Utah today, and across southern through east central Utah Thursday.

- There is a slight risk (level 2 of 5) for severe thunderstorms capable of producing strong winds and hail across southern Utah Wednesday afternoon and evening, and a 2% chance of a tornado. A Marginal Risk (level 1 of 5) for severe thunderstorms is in place on Wednesday across southern and western Utah on Thursday.

- The late week storm will also bring accumulating snowfall to the high terrain across northern and central Utah on Friday, with 1-4" likely above 9000 feet. Locally higher amounts are possible in favored locations.

DISCUSSION, Issued 1015 PM MDT Tue Oct 20 2026

Midday satellite imagery and objective analysis show an upper low spinning off the CA coast, with a deep layer of southerly flow extending downstream across much of AZ and southern UT. This flow has pulled tropical moisture northward into the region, which will enhance the threat for heavy rain and flash flooding across southern and central Utah over the next 36 hours. An embedded upper jet lifting through western AZ is aiding large scale ascent, and has resulted in numerous strong to severe thunderstorms across AZ over the past few hours, while precipitation has remained more stratiform extending into south central and southeast Utah.

As the upstream low encroaches on the CA coast this afternoon through tonight, increasing upper level diffluence will spread across southern and central Utah, resulting in an increase in showers and thunderstorms. With the increase in heavy rainfall flooding is expected within most drainages across south central Utah later this afternoon through tonight. Additionally, ample deep layer shear in excess of 40 kts will support supercells capable of all severe weather hazards this afternoon and evening across southern Utah where sufficient instability exists. It appears the most likely area for severe convection will encompass far south central and southwest Utah where breaks in cloud cover are allowing surface heating and destabilization of the airmass.

As the upper low spreads inland and across the western Great Basin Thursday, increasing large scale forcing will maintain showers and thunderstorms across southern and central Utah, with this activity spreading into northern Utah during the afternoon and evening hours. Ample deep layer shear will continue to support organized convection anywhere sufficient instability can develop through Thursday evening, particularly across southern and western Utah.

As the upper low quickly lifts through northern Utah into southern Idaho Thursday night into Friday, precipitation will wind down from south to north with time. Colder air being pulled into the area as this low passes will drop snow levels into the 8000-8500 foot range across northern Utah. Accumulating snow is still expected across the northern mountains above 9000 feet, however the overall evolution of the pattern and shorter duration of precipitation will likely keep accumulation limited to the 1-4" range, with a few pockets of higher amounts possible.

In the wake of this initial low, a secondary wave is forecast to dig into Arizona Saturday, before lifting into the central Rockies on Sunday. This will maintain cool temperatures through the weekend, with precipitation persisting across eastern portions of the forecast area. Beyond the weekend, drier conditions with seasonal temperatures are expected, however confidence is low in how the large scale pattern will evolve through next week.

AVIATION, Issued 1229 PM MDT Wed Oct 21 2026

KSLC...VFR conditions will persist for the KSLC terminal through the period. Isolated showers will push into the terminal area this afternoon before mostly dry conditions move in overnight with mid level cloud cover remaining. Mountain obscuration will be possible this afternoon. More showers and convection will redevelop tomorrow afternoon. Winds will remain out of the south with gusty conditions this afternoon and variable conditions associated with any showers impacting the terminal.

REST OF UTAH AND SOUTHWEST WYOMING...Mostly VFR conditions with some brief MVFR across the southern airspace through the period. Widespread showers and thunderstorms will continue across the southern airspace with isolated showers across the northern airspace this afternoon. Most of the activity shifts into the eastern airspace overnight. Mountain obscuration will persist for the southern airspace. Winds will primarily remain out of the south with gusts during the day, and variable gusty winds will be possible with nearby showers and storms that move near any terminals.

DISCUSSION

Not found in SLCFWFSLC.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Flood Watch through Thursday evening for UTZ117-120-121-123>131.

WY...None.