textproduct: Salt Lake City

KEY MESSAGES

- Northern valley inversions will remain in place through Friday. Increasing haze, decreasing air quality and areas of fog will continue.

- Approximately 50% of ensemble members bring sufficient mid- level cooling to at least partially ventilate the northern valleys Friday evening into Saturday morning.

- If valleys at least partially ventilate, with northwest flow remaining across the region early next week, valley inversions will remain weaker.

DISCUSSION...Northern valley inversions continue

as northwest flow remains in place across the Beehive State. A weak shortwave trough embedded in northwest flow will shift across northern Utah this afternoon. Given weak mid-level cold air advection, do not anticipate any relief from valley inversions with this shortwave trough, though areas above the inversions will see a few degrees of cooling from yesterday's (Wednesday's) highs.

A stronger shortwave trough will shift south and east into the Plains Friday into Saturday. Mid-level cold air advection associated with this developing trough will bring 700mb temperatures down to about -4C to -6C. Looking at model soundings, this may be enough to ventilate some northern valley locations. Right now, it looks to be about a 50/50 probability that valleys will see ventilation with this system.

The region will remain in northwest flow through most of the next week, which will avoid another round of substantial mid-level warm air advection. The majority of ensemble members keep 700mb temperatures at or below 0C through the remainder of the forecast period. While visibilities in haze may reduce through early next, inversions look to be significantly weaker.

Unfortunately, there isn't much of a chance of precipitation for the next 7 days.

For the short term, visibility reduction in haze will continue through at least Friday, with fog developing near the Great Sale Lake through Friday morning.

REST OF UTAH AND SOUTHWEST WYOMING

Persistent haze will bring MVFR VIS along the Wasatch Front throughout the TAF period. Isolated pockets of fog exist across northern Utah, mainly in the Bear River valley and near KBMC, but will burn off through the morning hours. Expect light, diurnally driven flows across all terminals today alongside clear skies.

SLC WATCHES/WARNINGS/ADVISORIES

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