textproduct: Salt Lake City

KEY MESSAGES

- Slight weakening of inversions has led to partial ventilation of valleys, but inversions will persist with patchy morning fog near the GSL.

- Dry conditions will persist through the next week or so with a large amount of uncertainty regarding the next storm at the end of next week.

DISCUSSION

Dense fog this morning along the south end of the Great Salt Lake was able to spill into portions of Tooele, Salt Lake, and Davis counties. This fog is still persisting southwest of Antelope Island. Expect more patchy dense freezing fog development overnight as skies remain clear with light winds.

Cooling aloft from the trough and arctic airmass moving across the eastern CONUS has led to some slight inversion improvements. Thermal profiles aren't as inverted as previous days, and air quality sensors have seen improvement over the last couple of hours as diurnal mixing helps to ventilate the valleys. Unfortunately, model soundings do show valley inversions building back into the area. The silver lining with this pattern is that we stay in a north/northwest flow regime that will prevent temperatures aloft from warming too much, which will help to limit the strength of the inversions.

Conditions remain dry through most of next week with the potential for a storm on Friday still in ~40% of ensemble members. But even if this storm does pan out, guidance doesn't have much moisture with the system.

Looking out further in time, the MJO will be switching to phase 7/8 which will favor a more active pattern by the end of the month and into February. Guidance is starting to show more troughs moving into the west by the end of the runs, which would coincide with the end of the month into early next month.

REST OF UTAH AND SOUTHWEST WYOMING

Valley haze along the Wasatch Front may be progressively less noticeable Friday, though the chance for significant slantwise reduction remains for sunset this evening and sunrise Friday. A period of fog development in low-lying areas has a ~20-40% chance of developing for the Cache valley, around the Great Salt Lake, and the West Desert between 14-18Z Friday as another night of significant radiational cooling is on deck. Winds will be generally light and terrain driven across the forecast area throughout the day, with the exception of southwest Wyoming at the far western periphery of a slow moving trough expected to just brush by the area through the next few days.

SLC WATCHES/WARNINGS/ADVISORIES

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