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 and variable flows are expected over the KSLC terminal through the morning hours, with a persistent south flow prevailing after 15Z. Afternoon wind gusts are expected to be around 20-25 kts. There is about a 25% chance that north winds push over the airfield around 01Z. Otherwise, south winds prevail through the period under VFR conditions.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions prevail areawide alongside breezy southwest winds. Southwest winds are expected to be 20-25 mph across a majority of the area, with the strongest winds (30-35kts) expected across the southwest area.

FIRE WEATHER, Issued 433 AM MDT Thu Sep 3 2026

Windy conditions are expected to resume today across much of Utah alongside continued low afternoon humidity values, especially across western Utah. With only marginal improvements to daytime relative humidity, strong winds will pair with this dry environment to create another day of locally critical fire weather conditions in western Utah, especially for areas that did not receive a sufficient amount of rainfall over the past week. Areas across the eastern half of Utah are expected to see a more noteworthy drop in relative humidity as compared to yesterday (about 5-10 percent lower) but still remaining above, or right around, critically dry thresholds (15 percent).

Moisture is expected to increase late in the week and through the weekend, bringing improvements to humidity values areawide. While overall moisture in the atmosphere will rise through the weekend, shower and thunderstorm activity is expected to be meager at best on Friday and Saturday, with coverage being limited to high terrain features in the southern Utah mountains. That said, a more significant push of moisture is anticipated to inundate the region by Sunday, bringing much greater coverage of showers and thunderstorms capable of producing wetting rains. A weak cold front may graze northern Utah late Monday/ Tuesday, bringing potential to shunt moisture out of Utah. Beyond early next week, the forecast becomes more uncertain.

SLC WATCHES/WARNINGS/ADVISORIES

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