textproduct: Salt Lake City

KEY MESSAGES, Issued 1009 PM MDT Tue Jul 28 2026

- Monsoon moisture will increase and spread northward for Wednesday, bringing a heightened threat of flash flooding, before building high pressure brings a drying trend Thursday through the weekend. - There is a high chance that temperatures will become extremely hot by the weekend as the ridge continues to build, bring the potential for an increase in heat related illness.

DISCUSSION, Issued 1009 PM MDT Tue Jul 28 2026

A broad ridge is centered over the central United States this evening, allowing for a southerly flow to develop over Utah and southwest Wyoming. The airmass over the area has remained relatively moist, with satellite derived PW values in the 0.8 to 1.0 range across much of the area, highest over southern Utah. Earlier showers and storms over southern Utah are decreasing in coverage at this time. However, a series of weak shortwaves moving north across Utah overnight will allow for some showers to continue into the morning.

The southerly flow will allow moisture over the area to increase and spread northward through tomorrow afternoon, with PW values of an inch or more expected to spread over the vast majority of the forecast area. Combined with the supplemental instability from the shortwaves, this will bring another round of showers and thunderstorms, and any storms that develop will be capable of producing heavy rain that could lead to flash flooding. The showers and associated cloud cover area expected to keep high temperatures near to just below seasonal normals during the day.

Beginning Thursday, the broad ridge is expected to re-orient itself over the west, with the center moving directly over Utah for the weekend. This will add a westerly component to the flow aloft that will draw a drier airmass into the area, decreasing the threat of convection. As the ridge strengthens, temperatures will become increasingly hot, peaking on Saturday with 700mb temperatures expected to be in the lower 20s Celsius across the entire area. This will result very hot temperatures that will increase the risk of heat related illness, particularly for valley locations. Some uncertainty remains with regard to how high the HeatRisk will get on Friday, with Thursday nights lows potentially getting low enough to keep the HeatRisk in the orange (moderate) range for much of northern Utah during the day. For Saturday and Sunday, confidence is higher than usual in the potential for very hot maximum temperatures, but there remains a good amount of spread in the ensembles with regard to low temperatures and therefore how much overnight relief the area, northern Utah in particular, will see. Therefore, have decided to hold off on an Extreme Heat Watch at this time due to uncertainty about the length of time of the event.

By early next week, the ridge is expected to weaken a bit and shift south as a Pacific Northwest trough moves over the top of it. This would provide some relief from the heat, at least for northern portions of the area, though there remains a good amount of spread in the guidance with regard to how much the trough will act to weaken the ridge and therefore how much of a drop in temperatures there might be. It does seem likely, however, that the very hot weather will continue for at least southeast Utah.

AVIATION

KSLC...There is a 30% chance for showers to impact the terminal with variable winds between 12-15z. Otherwise, showers continue along the high terrain east of the terminal through the evening. Showers and thunderstorms moving in from the west after 00z have a 30% chance to bring gusty and erratic outflow winds to 40-45 kts through around 04z. VIS reductions are also possible with storms this evening, with potential to result in brief MVFR conditions. Convective activity tapers thereafter, with generally light southeasterly winds prevailing overnight.

REST OF UTAH AND SOUTHWEST WYOMING...Showers across central Utah will continue spreading northeast through early this afternoon. Additional development of showers and thunderstorms are expected across southern Utah this afternoon and evening, moving into northern Utah and southwest Wyoming later in the evening. Storms today will be capable of producing gusty and erratic outflow winds to 45 kts as well as brief heavy rainfall that could produce brief VIS reductions to MVFR. Conditions quickly dry out areawide after 06z, with generally light terrain driven winds prevailing overnight.

FIRE WEATHER, Issued 214 AM MDT Wed Jul 29 2026

Scattered showers and thunderstorms are expected to develop early this morning across central Utah, spreading northward through late morning. Another round of showers and thunderstorms develops early this afternoon across southern Utah, with coverage becoming more widespread across the state through the remainder of the afternoon. Expect activity to taper off late tonight. Storms today will be capable of producing locally heavy rainfall, lightning, and gusty and erratic outflow winds upwards of 40 to 50 mph. Monsoonal moisture is flushed out of the state quickly on Thursday as high pressure strengthens across the western US, introducing a much drier airmass through at least early next week. This pattern will also result in temperatures trending 5 to 10 degrees warmer this weekend. Given the combination of unseasonable heat and relative humidity values reaching critical values statewide by Friday, heightened fire weather concerns will exist through the weekend especially across the western half of the state.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Extreme Heat Watch from Friday afternoon through Sunday evening for UTZ123-124-128-131.

WY...None.