textproduct: Salt Lake City

KEY MESSAGES

- High based showers and thunderstorms will develop over northern Utah and southwest Wyoming late this afternoon into the evening, with any storms that develop capable of producing strong to severe wind gusts, with the threat returning Wednesday afternoon and evening.

- Gusty winds and low relative humidity will combine to produce areas of critical fire weather conditions over some southern Utah valleys this afternoon. The threat of critical fire weather conditions will expand into the mountains of southern Utah for Wednesday.

- There is increasing confidence that a notable heat wave will develop over the weekend, with many valleys forecast to see HeatRisk values in the red (major) range, and some northern Utah valleys seeing values in the purple (extreme) range Saturday into Sunday.

DISCUSSION

A broad area of high pressure is centered over the central United States this morning, with Utah and southwest Wyoming under a breezy southwest flow on the back side of this feature, enhanced by some shortwave energy moving over the top of the ridge. Highs today will be similar to yesterday, with maxes running up to 5F above seasonal normals. Though the southwest flow is drawing some moisture northward, relative humidities will still be low enough in some valleys of southern Utah to combine with the breezy winds to result in areas of critical fire weather conditions.

Guidance continues to indicate a setup favorable for another round of strong to severe convection for northern Utah and southwest Wyoming this afternoon. A shortwave is expected to move over northern portions of the area late this afternoon into the early evening with some decent jet support providing upper level divergence. Combined with anticipated bulk effective shear of 30-40 kts, this has the potential to bring a bit of more organized convection. Given the high based nature of these storms, primary threat will be strong, gusty outflow winds and isolated dry lightning. However, cannot rule out some hail. Overall, have increased POPs a bit over northern Utah to account for the threat and extended the mentionable POPs into the first part of the overnight hours given model trends.

With the central US ridge expected to weaken tomorrow, the flow aloft over the area is expected to have more of a westerly component, tapping into a dry slot over the California coast. This will drop relative humidities from southwest to northeast over the forecast area, resulting in more widespread critical fire weather conditions as winds remain elevated. Some moisture will remain over parts of northern Utah and southwest Wyoming, with more shortwave energy expected to move through during the late afternoon and early evening once again. This feature looks better defined than the one expected today, with a weak boundary in association with it, so if anything seeing better dynamics for tomorrow compared to today, though the main threat will shift slightly farther north.

Drier air is expected to continue to move in through the remainder of the work week. By Friday, a ridge centered near southern Nevada will start to expand, before the axis shifts overhead Saturday and east of the area on Sunday. There is high confidence that this will bring some of the hottest temperatures of the season so far, particularly for northern Utah and southwest Wyoming. HeatRisk forecasts show red (major) values for many valleys across the area, with perhaps the exception of the lowest southern Utah valleys. By Sunday, there is an increasing chance of purple (extreme) HeatRisk values for some northern Utah valleys, including the Cache Valley and Wasatch Front. There is high confidence that these highs will challenge at least daily records, with some guidance indicating monthly records, and, in the case of Logan, all-time records will be in play. Predictably, this will significantly increase the chance of heat related illnesses across the area over the upcoming weekend.

As the ridge continues east of the area early next week, there is increasing confidence that temperatures will move from extremely hot to just hot, with guidance showing highs "just" 5-10F above seasonal normals by day seven. Increasing southerly flow could also bring a return of moisture by the middle of next week.

AVIATION, Issued 1042 PM MDT Mon Jul 6 2026

KSLC...Winds expected to gradually settle southerly overnight with SCT to BKN VFR clouds lingering above ~12 kft. Winds then anticipated to shift NW around 18-20Z. There will once again be potential for afternoon convection and associated erratic gusty outflows, though at this time it is around a 10-20% chance of impacts at the terminal. Otherwise, VFR skies with mid/upper level clouds continue to prevail.

REST OF UTAH AND SOUTHWEST WYOMING...Forecast pattern for Tuesday looks similar to that of Monday as the associated system lingers. This will result in afternoon convective potential at northern terminals, though with less coverage expected than Monday, and favoring areas further north and east. Still, this will result in potential for some gusty erratic outflow which would interrupt the typical diurnal wind cycle if near any terminals. Skies largely expected to remain VFR with SCT to BKN cloud cover generally above 10 kft. At southern terminals, clear conditions are maintained, with fairly typical wind directions and speeds.

FIRE WEATHER, Issued 658 AM MDT Tue Jul 7 2026

High pressure near the Four Corners region this morning will shift westward across Arizona, allowing a drier westerly flow to spread into Utah through the mid to late week period. However, lingering moisture today will maintain isolated to scattered showers and thunderstorms, mainly initiating over and near the northern and central mountains and northwest Utah and shifting into the adjacent valleys to the east. While isolated pockets of wetting rain will be possible, the bulk of the showers will remain high-based, resulting in a threat of isolated dry lightning and gusty outflow winds. As increasingly drier air spreads into the area, the convective threat will then decrease each day into Thursday and will become increasingly confined to northern Utah.

In addition to the dry lightning threat, the westerly winds will increase enough that, when combined with decreasing humidities, near-critial to critical fire weather conditions will develop, mainly in portions of central and southern Utah through at least Wednesday and potentially into Thursday.

By the end of the week and through the beginning of next week, high pressure will strengthen over Utah, bringing dry and hot conditions to the area. Valleys will likely exceed 100 degrees, especially Saturday and Sunday. These hot temperatures will be paired with low afternoon relative humidities mostly in the single digits. However, a potential moisture surge is on the horizon, which could bring a cooling trend and an increased potential for wetting rain by the middle of next week.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Red Flag Warning until 9 PM MDT Wednesday for UTZ492-495-497-498.

Red Flag Warning from noon to 9 PM MDT Wednesday for UTZ493-496.

WY...None.