textproduct: Salt Lake City

KEY MESSAGES

- High pressure will bring hot and very dry conditions through the first half of the upcoming week. There is a greater than 50 percent chance HeatRisk will reach the major category across the lower deserts of southern Utah including Zion National Park and St George Tuesday and Wednesday.

- Elevated to locally critical fire weather conditions will impact portions of central and eastern Utah on Monday.

- Gusty northwest winds combined with hot and very dry airmass will result in critical fire weather conditions Tuesday and Wednesday across much of the state where fuels are critically dry.

DISCUSSION

An upper low spinning over northern California has helped pull moisture northward into southern and eastern Utah, where showers and thunderstorms once again developed by early afternoon. These storms have been decreasing over the past couple of hours as instability wanes, and will continue to diminish over the next few hours. This upper low will weaken and retrograde back over the eastern Pacific later tonight through Monday, as mid level ridging builds into the Pacific Northwest and northern Great Basin. A drier northwest flow will erode this moisture over southern Utah, although hi-res guidance suggests enough moisture will lingering to support a few high based showers/dry thunderstorms Monday afternoon mainly across the southern mountains.

As mid level ridging becomes established just upstream of the forecast area, a hot and very dry airmass will build into the forecast through midweek. By Tuesday temperatures will be running 7-10 degrees above climo, with max temps exceeding 105F around St George and Zion Canyon. This will push the HeatRisk into the moderate category across most lower elevations across the forecast area, with local areas of southern Utah potentially reaching the major category Tuesday and Wednesday. Additionally, a shortwave trough passing northeast of the area late Tuesday into Wednesday will enhance northwest winds across areas east of I-15, resulting in critical fire weather conditions where fuels are sufficiently dry.

Later in this week this ridge axis will weaken as it shifts overhead, eventually allowing for a southwesterly flow to become established across the forecast area by Friday as an upper trough develops along the Pacific Coast. This will result in a slight cooling trend, but the increase in southwest flow late in the week will shift the focus for critical fire weather conditions into western Utah. As this trough moves inland, associated moisture and dynamics will bring a chance for precipitation to northern Utah next weekend.

AVIATION...SLC

VFR conditions will persist at KSLC through the TAF period. Winds overnight will remain southeasterly with periods of light and variable, before northwest winds become re- established by 16Z Monday.

REST OF UTAH AND SOUTHWEST WYOMING...Lingering showers and thunderstorms across southern Utah may bring gusty erratic winds to KCDC and KSGU through 06Z. Otherwise VFR conditions will prevail across all terminals through the period with general northwest winds redeveloping Monday morning.

FIRE WEATHER

Convection across southern and eastern Utah is diminishing this evening. Lingering moisture will result in isolated high based showers and dry thunderstorms across portions of southern Utah Monday afternoon. Otherwise a drier pattern will build into the region Monday, with locally elevated to locally critical fire weather conditions across portions of central and eastern Utah Monday afternoon and evening. Northwest winds will increase on Tuesday, with critical fire weather conditions expected across the eastern valleys as well as the central and southern mountains. Winds will increase a bit more on Wednesday...which may spread critical fire weather conditions into the Grand Staircase. While winds will decrease Thursday a bit, eastern valleys, and the central and southern mountains will likely remain in critical fire weather conditions through Friday. Overnight recoveries in these areas will become quite poor Tuesday night through at least Thursday night.

As a system approaches the Pacific Coast Thursday into Friday, winds will also increase across the western valleys, bringing a threat of critical fire weather conditions to these locations as well.

Bottom line, the threat of wetting rains will end today...followed by an extended hot, dry, and gusty period for most of the next week.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Fire Weather Watch from Tuesday afternoon through Wednesday evening for UTZ482-488-489-493-496.

WY...None.