textproduct: Salt Lake City

KEY MESSAGES

- Dangerous heat will continue through Saturday across southern Utah, through Sunday for the remainder of the Utah. Those without access to cooling or proper hydration will be most at risk for heat- related illness. With temperatures remaining elevated overnight, there will be little recovery. Heat stress is cumulative.

- Critical fire weather conditions will continue across southern Utah today as widely scattered thunderstorms develop after a long duration period of very dry, very hot conditions. This threat will spread north and east this weekend into Monday.

- A marginal risk of excessive rainfall has been outlooked across southern Utah Friday and Saturday, shifting north and east Sunday.

DISCUSSION

A quick discussion today as active weather continues. Looking at the latest mesoanalysis, SBCAPE continues to climb to near 1000-1500 J/kg. With little deep layer shear, storm motions have been very slow. The biggest question in regard to any flash flood threat will be whether storms are able to sustain shear/cold pool balance and continue to shift with outflow boundaries. This will be something to monitor over the next few hours.

Excessive Heat Warnings and Heat Advisories continue for many locations. For southern Utah, these continue through Saturday, the remainder of Utah through Sunday. No changes were made with this package to the heat headlines.

Looking at the latest runs of the HRRR, CAMs may be trending toward more convective coverage Saturday. SBCAPE values will be slightly less than today, with little to no deep layer shear. Cold pool/shear balance will be a question again.

This monsoon surge will continue to spread north and east Sunday into Monday and continue through much of the week. Storm motions and shear will increase to an extent Sunday into early next week, which may allow for more intense rainfall rates.

AVIATION...KSLC

Winds will be light and variable over the next hour or so, becoming stronger out of the northwest between 1830-1900z. A transition back to southeasterly drainage winds is expected around 03-04z, however winds may also be light and variable during the overnight hours. VFR conditions will prevail most of the time, though wildfire smoke may cause slantwise VIS reductions briefly into MVFR, particularly around sunrise/sunset.

REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and isolated thunderstorms will develop after 18-19z across primarily southwestern Utah south of KDTA and west of KBCE, though some storms may reach northward into Utah County, potentially impacting KPVU this afternoon. Storms will be capable of producing gusty outflow winds up to 40kts (up to 30-35kts further north). Otherwise, winds will follow typical diurnal trends. VFR conditions will largely prevail, however wildfire smoke may cause slantwise VIS reductions briefly into MVFR (or lower very close to local wildfires).

FIRE WEATHER

Widely scattered thunderstorms will continue to develop across southwestern Utah this afternoon and evening. Given very dry and very hot antecedent conditions, issued a Red Flag Warning for zones 495 and 496 for this afternoon and evening. Convective coverage will trend lower for Saturday...before increasing once again on Sunday across much of the higher terrain of Utah. This trend will continue into the next workweek.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Extreme Heat Warning until midnight MDT Sunday night for UTZ101- 102-104-105-115-120-121.

Heat Advisory until midnight MDT Sunday night for UTZ103-106-107- 114-116.

Heat Advisory until 9 PM MDT Saturday for UTZ118-119-122-126-127.

Red Flag Warning until 9 PM MDT this evening for UTZ495-496.

Extreme Heat Warning until 9 PM MDT Saturday for UTZ123-124- 128>131.

WY...Red Flag Warning until 9 PM MDT this evening for WYZ277.