textproduct: Salt Lake City

KEY MESSAGES

- Showers and isolated thunderstorms with the potential for gusty outflow/microburst winds exist for today and tomorrow, primarily across the northern 2/3rds of the area.

- Freezing temperatures across the Cache Valley (Wednesday morning only), western Uinta Basin, and Sanpete valley Wednesday and Thursday morning.

DISCUSSION

A cutoff low is situated off the central California coast while a trough is diving south across the northern plains. These two features will help to initiate showers with isolated thunderstorms through Wednesday morning before a relatively quiet period sets up for the remainder of the period. Ensemble members are is good agreement regarding a broad ridge of high pressure building into the western CONUS by the weekend and into early next week.

Mid and upper level moisture with a relatively dry surface layer exists across central and northern Utah/SW Wyoming. This moisture will result in showers and isolated thunderstorms developing today. Drier air is starting to move into southern Utah, which will limit convective activity near the Arizona border. Instability will be marginal today with the best CAPE and DCAPE across northern Utah. Wind shear is weak across the area which will keep showers and storms in a short-lived mode. Weak steering flow will also inhibit showers from being able to move off of the terrain and into adjacent valleys. But these showers could produce some gusty microburst winds as they collapse.

Convection will be slightly more widespread on Tuesday as there will be better proximity to dynamics associated with the approaching trough to our northeast and closed low coming from the west are able to provide more lift for storms. Profiles aren't quite as dry near the surface for tomorrow, so microburst winds will be less pronounced. Showers will start to push to the east and will clear the area by Wednesday morning as a cold front sweeps through the area.

This front will bring back the threat for freezing temperatures across the Cache Valley Wednesday morning and the western Uinta Basin and Sanpete Valley both Wednesday and Thursday morning. Wednesday morning has ~30-50% chance of freezing temperatures in these locations. The main source of uncertainty is likely associated with residual clouds and moisture behind the front. If conditions are able to clear out sufficiently before sunrise on Wednesday then freezing temperatures will have a better chance of occurrence. Thursday morning won't have the threat of cloud coverage, but temperatures will already be warming aloft by then so the threat of freezing temperatures will be confined to the Sanpete Valley and western Uinta basin.

With troughing to our east and ridging building to our west we will be in a mostly stable northwest flow through the weekend. Grazing shortwaves will remain possible within this flow regime, particularly across northern Utah/SW Wyoming so diurnal showers can't be totally ruled out. A more prominent ridge will start to build across the west by early next week which will lead to dry stable conditions with warmer than normal temperatures.

REST OF UTAH AND SOUTHWEST WYOMING

Showers and thunderstorms will continue to develop from a line roughly north of CDC to BCE to HVE to a line roughly south of ENV to OGD to EVW through 03Z. Gusty and erratic microburst winds up to 50 mph and brief periods of MVFR will occur near this convection. Additional showers and thunderstorms will impact portions of Utah between OGD and Nephi between 03-10Z.

SLC WATCHES/WARNINGS/ADVISORIES

UT...None. WY...None.