textproduct: Salt Lake City

KEY MESSAGES, Issued 1001 PM MDT Wed Sep 2 2026

- Gusty southwest winds are expected each afternoon and evening across Utah and southwest Wyoming through the end of the work week. With minimum relative humidities approaching critical values in pockets of western Utah, this will result in some locally critical fire weather conditions.

- An influx of tropical moisture over the holiday weekend will increase the risk of flash flooding into early next week, particularly on Sunday across central and southern Utah.

DISCUSSION, Issued 1001 PM MDT Wed Sep 2 2026

Utah and southwest Wyoming remain sandwiched in between an upper low off the Pacific Northwest coast and a broad ridge over the central United States. This has resulted in a persistent breezy southwesterly flow that is advecting drier air into the area. Thursday is anticipated to be the driest day for the region, with minimum relative humidity values approaching critically low values for portions of western Utah, the northwest desert in particular. This will likely result in some locally critical fire weather conditions during the afternoon, but given the improvement in fuels from recent rains, the fire danger is not as high as it could be. The airmass over the area will stay just a bit on the cool side, with maxes running near to up to 5F below seasonal normals through the end of the work week.

As we enter the holiday weekend, all eyes will turn to the eastern Pacific where Hurricane Marie is currently tracking westward away from Mexico. Guidance continues to indicate that the southerly flow will tap into deep tropical moisture from the system, bringing that moisture up through Utah and southwest Wyoming by Sunday. This influx of moisture will bring the return of fairly widespread coverage of showers and thunderstorms, with any storms that develop capable of producing heavy rain that could lead to flash flooding.

There remains lower confidence than usual in the timing of the arrival of this moisture and its trajectory, as this is dependent on the precise track of Marie, something that global models can struggle with, and also the trough currently over the Pacific Northwest. The prevailing thought is that the system will spin just off the coast through the first part of the weekend before eventually grazing northern Utah early next week. Its passage is expected to give a more westerly component to the flow, cutting off the tropical moisture and bringing drier air back in. However, there remains disagreement as to when it will graze the area, and how far south the system will actually get. Hopefully details will become a bit clearer over the next few days.

AVIATION

KSLC...Light, westerly winds will likely shift back to southeasterly by 08-09z, though there is a chance that winds remain light and variable overnight. Southerly winds will begin to pickup after 16z, with gusts to 20-25kts through the afternoon. VFR conditions will prevail.

REST OF UTAH AND SOUTHWEST WYOMING...Southwesterly to southerly winds will persist through the overnight hours at most sites south of and including roughly KU19-KSVR-KEVW. North of this boundary, sites have been slowly shifting to westerly/northwesterly, and will become largely light and terrain-driven overnight. Strong southwesterly winds will return after 15-17z Thursday across much of the area. VFR conditions will prevail.

FIRE WEATHER, Issued 1001 PM MDT Wed Sep 2 2026

Breezy southwest flow will remain over the state through the end of the workweek, with isolated gusts in excess of 40 mph developing both Thursday and Friday afternoons. Drier air continues to advect into the state, with isolated pockets of minimum RHs near critical values developing again both Thursday and Friday. This combination will bring some locally critical fire weather conditions, but coverage will not be enough to warrant headlines, especially considering the improved nature of fuels. Deep tropical moisture associated with Hurricane Marie will spread northward across the state over the weekend, particularly on Sunday, bringing a high chance of wetting rainfall and an increased threat of flash flooding, before drier conditions return by the middle of next week.

SLC WATCHES/WARNINGS/ADVISORIES

UT...None. WY...Red Flag Warning until 9 PM MDT Thursday for WYZ277.