textproduct: Salt Lake City

KEY MESSAGES

- Dry conditions with valley inversions persisting through Thursday before valley rain and mountain snow arrive this weekend that will help to mix out the inversions.

- Another storm early next week could bring cooler temperatures aloft and more widespread precipitation, but confidence is low on the timing and track.

DISCUSSION

A weak dry shortwave moved through this morning with a few mid level clouds. However, given the light winds at the surface and aloft this passage didn't mix valley inversions out very well. The 12Z sounding showed this inversion well, and inversion conditions will likely persist through Thursday before a more substantial storm moves through the area on Saturday.

Southwesterly flow will start to increase ahead of an elongated trough on Friday. Current guidance has elevated winds increasing at the surface for western portions of the CWA. If they are able to break through the surface inversion then hazy conditions in the valleys could see improvement as early as Friday. Otherwise, improvement will likely come on Saturday as widespread valley rain and mountain snow move through most of the CWA. Confidence is highest regarding the speed in which this trough moves through. Most of the guidance have it moving through relatively quickly which will limit precip duration and totals. Confidence is still shaky regarding the track of this trough. 44% of ensemble members keep the trough to the west with a drier solution that would result in little accumulation of valley rain and mountain snow. Whereas the other 56% of members bring a quick round of valley rain (0.15-0.4") and mountain snow (4-8" above 8000 feet).

A more substantial and potentially colder storm early next week could provide for high precipitation totals and lower snow levels. The clusters are split into two scenarios. The first (67% of members) scenario brings more of an open wave through the Great Basin with widespread valley rain and mountain snow. The second (33% chance) scenario has a splitting storm that brings the greatest precipitation to the desert southwest with some precipitation making it into southern Utah. Median 700 mb temperatures dip to -7C with this storm which could bring snow levels as low as 6000-6500 feet.

AVIATION

KSLC...VFR conditions will prevail with light, terrain-driven winds. Northwesterly winds will prevail this afternoon, but may become light and variable at times. Southeasterly winds will return after 02-03z.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail with light, largely terrain-driven winds. A westerly to northwesterly direction will be favored this afternoon across Uinta Co., WY.

SLC WATCHES/WARNINGS/ADVISORIES

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