textproduct: Salt Lake City

KEY MESSAGES

- Isolated to widely scattered convection across southern and central Utah Friday.

- An approaching trough will bring cooler temperatures and 50% chance for widespread precipitation Sunday-Tuesday, with tropical moisture potentially leading to locally significant amounts.

DISCUSSION

Weak, diffuse low pressure is in place this evening across AZ and extending into UT and eastern CO. This, combined with PWATs near 0.7 inches allowed isolated to widely scattered weak convection to develop over mainly the southern Utah mountains this afternoon which have now mostly dissipated, leaving some mid and high clouds in place that will continue over much of southern and eastern Utah into Friday morning.

An upper trough currently noted off the PacNW coast will make its way inland tonight, crossing ID Friday before ejecting across western MT. Ahead of this trough, isolated to widely scattered convection can be expected once again Friday afternoon. These are expected to develop over the southern and central Utah mountains, then shift into the adjacent eastern valleys with the flow aloft turning more westerly. A shallow cold front will push into northwest Utah Friday night, bringing slightly cooler temperatures to that area through Saturday.

With generally dry and stable conditions expected on Saturday, attention then turns to the next trough, which will be deepening off the West Coast on Sunday. Ahead of this trough, a vort max originating near Hurricane Odalys in the eastern Pacific is progged to lift into Utah Sunday afternoon, bringing an increase in moisture and some widely scattered convection. The trough itself is progged to approach Utah by Monday. Latest deterministic EC/GFS and an increasing number of global ensemble members are trending towards a splitting, closed-low evolution, which would bring the system farther south with a slower eastward progression. This would result in the system being able to better tap moisture from Hurricanes Odalys and Polo, with longer duration precipitation potentially aiding greater amounts. Widespread precipitation appears likely across southern and eastern Utah, but at this time, quite a bit of uncertainty remains with regards to precipitation amounts, with a large spread in the NBM 25th-75th percentile amounts. For example, many southeast Utah valley areas have 48-hr totals Monday through Tuesday of 0.10 inches or less at the 25th percentile but around 1 inch or more at the 75th percentile. However, even with the uncertainty, the amounts at the higher end of the probabilistic spectrum have been climbing, meaning increasingly greater amounts are becoming possible.

Besides precipitation, the trough will bring cooler temperatures into the area, with afternoon maxes falling 5-10 degrees below normal for Monday and Tuesday, with many valleys reaching low 70s at best. Temperatures will slowly rebound midweek as the storm system exits the area, but significant spread exists in the large scale pattern for the second half of next week.

AVIATION

KSLC...VFR conditions will continue through the TAF period. Southeasterly winds will prevail overnight, becoming southerly and gusty Friday morning around 15Z, before a delayed return to northwesterly around 20Z Friday.

REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will continue through the TAF period at all terminals. Diurnally driven winds can be expected at all terminals through mid-morning Friday, before winds become southwesterly late morning through afternoon.

FIRE WEATHER, Issued 1040 AM MDT Thu Sep 24 2026

A relatively quiet and seasonable pattern will continue for the next several days as dry air and stable conditions cover most of the region. Moisture across the Four Corners will keep isolated storms possible across southern and southeastern Utah today and tomorrow. Most of this activity will be confined to the higher terrain, but rain rates could be heavy given the moisture content. Winds will start to increase out of the southwest this weekend ahead of an approaching storm that could mix with tropical moisture for widespread heavy precipitation early next week.

SLC WATCHES/WARNINGS/ADVISORIES

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