textproduct: Salt Lake City

KEY MESSAGES, Issued 1216 PM MDT Sun Jun 21 2026

- High pressure will bring a warming trend early this week. Daytime temperatures will run 5 to 10 degrees above normal by Tuesday, with hot conditions continuing through at least Thursday. The potential for heat related illness will increase across valley locations by the middle of the week.

- Moisture spreading northward will bring a chance for showers and thunderstorms Wednesday and Thursday, with the greatest chance for precipitation across southern Utah. Lightning associated with these storms may result in new fire starts.

- Strengthening and drying southwesterly flow ahead of an approaching cold front will bring the return of critical fire weather conditions late in the week.

DISCUSSION, Issued 1216 PM MDT Sun Jun 21 2026

A slightly cooler and more stable airmass has spread across much of the forecast area today in the wake of Saturday's cold front passage. As a result a lighter northwesterly low level flow will persist through this afternoon and early evening with seasonal temperatures and slightly higher relative humidity. The exception is far southern Utah in vicinity of the lingering surface trough, where a westerly flow and slightly warmer airmass remain in place.

Mid level ridging will build across the Desert Southwest through the early portion of the week, allowing for a warming and drying trend across the forecast area. By Tuesday max temperatures will once again run 5-10 degrees above climo, with low-mid 90s along the Wasatch Front Tuesday climbing into the mid to upper 90s Wednesday. Lower deserts of southern Utah including St George, Zion Canyon and Bullfrog will reach or exceed 105F each afternoon. With these temperatures and elevated overnight lows, HeatRisk will reach the moderate category across most valleys with pockets of high, and will be accompanied by an increased risk for heat related illnesses.

Model guidance is coming into better agreement pulling moisture northward into the Desert Southwest around the periphery of the upper ridge, and spreading into southern Utah by Wednesday. Initially this moisture will likely be elevated with a deeply mixed sub cloud layer favoring dry lightning and microburst winds Wednesday, with perhaps a better chance for precipitation by Thursday.

There is also fair agreement late in the week heading into next weekend bringing an upper trough into the Pacific Northwest/northern Great Basin. The resultant strengthening southwesterly flow would advect drier air back into the state and result in another round of critical fire weather conditions Friday into Saturday.

AVIATION, Issued 1216 PM MDT Sun Jun 21 2026

KSLC...Northwesterly winds will persist through the early evening, becoming light and variable after ~03-04z. VFR conditions will likely prevail, however smoke from nearby wildfires could produce periods of MVFR VIS, particularly around sunset/sunrise and again Monday afternoon.

REST OF UTAH AND SOUTHWEST WYOMING...Winds will remain relatively light and terrain-driven across much of the area, except for the western Uinta Basin where westerly winds will gust to around 20- 25kts through roughly 02z. Although many sites will experience VFR conditions, wildfire smoke could result in reductions in slantwise VIS, particularly around sunrise/sunset.

FIRE WEATHER

A slightly cooler and more stable airmass has spread across much of the state, resulting in a general northwesterly flow and seasonal temperatures this afternoon. Although RH has trended slightly higher, values will still remain near or below 20 percent across most low and mid elevations into the early evening hours. Near the Arizona border, the airmass remain hot and very dry, and gusty west winds will result in local critical fire weather conditions in portions of zones 496 and 498 through early evening.

High pressure will strengthen across the area during the first half of the week, resulting in a return to hot and very dry conditions by Tuesday. Daytime temperatures Tuesday and Wednesday will run 5-10 degrees above normal with very low daytime RH and marginal to poor overnight recovery. With this strengthening high, general winds will remain fairly light from the west to southwest. The exception will be portions of south central and east central Utah, where gusts may locally exceed 25 mph and result in pockets of locally critical fire weather conditions in zones 482, 489 and 498

High based moisture will begin to increase Wednesday afternoon across southern and potentially central Utah, bringing a chance for high based showers and dry thunderstorms. This moisture looks to increase on Thursday, bringing a mixture of wet and dry thunderstorms. A dry and strengthening southwesterly flow will follow Friday into Saturday as this ridge breaks down, which will likely bring a return to critical fire weather conditions across much of the area.

SLC WATCHES/WARNINGS/ADVISORIES

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