textproduct: Salt Lake City

KEY MESSAGES, Issued 123 PM MDT Fri Sep 4 2026

- Gusty winds out of the southwest persist through at least Sunday across much of Utah and southwest Wyoming, with an emphasis on areas west of I-15.

- Tropical moisture advects north into Utah Sunday increasing chances for precipitation.

- Threats for both flash flooding and severe weather look to develop on Sunday with the arrival of tropical moisture.

- The active upper air pattern continues into next week, potentially resulting in more precipitation by mid-week following an early week lull.

DISCUSSION, Issued 123 PM MDT Fri Sep 4 2026

Currently, a large upper low is slowly moving into the Pacific NW, deepening with eastern extent. A tight southwest- northeast oriented pressure gradient exists across nearly all height levels resulting in another afternoon of enhanced southwesterly flow overhead. With another clear and dry afternoon, mixing has already begun as surface temperatures warm up statewide with enhanced southwesterly gusts making it down to the surface. Most areas across UT and SW WY can expect to see gusts in the 25-35mph range, though areas west of I-15 may see gusts approach (and potentially exceed) 45mph given stronger winds aloft with higher surface temperatures to encourage stronger mixing. This general pattern is expected to continue into Sunday with enhanced afternoon dry southwesterlies developing around the 10AM-12PM timeframe each day.

Come Sunday, moisture associated with Hurricane Marie is forecast to phase into the mean upper flow as a result of the southern stream increasing in strength. As a result, PWAT anomalies on the order of 0.5-0.8 above seasonal normals (potentially exceeding 200% normal values) are forecast to push north across much of Utah. Widespread ascent will overspread as the strengthening southern stream phases into the mean flow with the aforementioned upper low, resulting in a somewhat quicker eastward progression over time. As such, widespread showers and thunderstorms are forecast to develop in the morning hours across much of southern and central UT, potentially nudging into northern UT as well. While enhanced flow aloft suggest fast moving storms, the overall moisture content within the atmosphere and preceding wet conditions from rainfall earlier this week across portions of central and southern UT leads to some degree of flash flooding concerns on Sunday. Current guidance suggests hourly rainfall rates ranging from 0.4-0.6"/hr, with some isolated rates nearing 0.8-1"/hr rates possible. Some uncertainties still exist with this setup, particularly surrounding how quickly the system ultimately moves out of the region, though heavy rainfall appears likely regardless of timing.

Additionally, a mentionable threat for severe weather exists across primarily northern and central UT Sunday afternoon given the strength of the upper trough. Bulk shear values ranging from 30- 50kts appears likely given the strength and persistent deepening of the upper level low, though timing may serve to limit this event overall. Previous runs were much slower with the progression of this system, though guidance has sped up the eastward progression considerably over the last day. This has resulted in a shorter window for destabilization, with limited CAPE areawide keeping this event more isolated than previously thought with respect to severe thunderstorms. Regardless, an impressive kinematic environment exists and trends will be monitored going forward.

Come Monday and Tuesday, the upper low progresses east leaving the forecast area in a dry westerly flow regime keeping conditions calm to start the week. Come Wednesday, another shot of moisture looks to advect north as another strong upper low dives south along the CA coastline putting the forecast area beneath enhanced southwesterly flow once again. Considerable uncertainty remains in place regarding the upper air pattern moving into later next week and the progression of the aforementioned upper low, though a return to a wetter pattern appears favored following Wednesday next week.

AVIATION

KSLC...VFR conditions will persist for the KSLC terminal through the period. Dry conditions will continue with a few high clouds. Winds will remain breezy out of the south for the duration of the period with the strongest wind gusts during the day.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist for the entire airspace through the period. Dry conditions will continue with a few high clouds. Winds will remain breezy out of the southwest for the duration of the period with the strongest wind gusts during the day.

FIRE WEATHER, Issued 123 PM MDT Fri Sep 4 2026

Moisture will continue to gradually increase into the weekend as southwesterly flow pushes moisture further north. Today and tomorrow, expect locally critical fire weather conditions primarily across the West Desert and Great Salt Lake Desert where humidities may drop below 15%. Additionally, strong wind gusts across areas primarily west of I-15 will range from 30-45mph each afternoon into Sunday.

On Sunday, a stronger push of moisture arrives to Utah with widespread showers and thunderstorms across the state, though primarily across central and southern Utah. Temporary drying is expected Monday and Tuesday, though the pattern developing midweek supports another round of moisture pushing north subsequently increasing chances for showers and thunderstorms across Utah once again.

SLC WATCHES/WARNINGS/ADVISORIES

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