NZUS95 KSLC 011638
LLLSLC
UTZ101>131-WYZ021-020438-

Public Information Statement
National Weather Service Salt Lake City UT
1038 AM MDT Wed May 1 2024

.LONG TERM (After 12Z/6AM Friday)...The long-term period begins with another shortwave trough grazing northern Utah, bringing isolated showers to the northern third of Utah and southwest Wyoming on Friday before drying out in the evening and overnight. A shortwave ridge will then build across Utah on Saturday, but this feature will be transient as another strong closed low forming off the coast of the PacNW begins to move inland. Increasing southwesterly flow is also expected on Saturday along with strong warm-air advection with H7 temperatures reaching +7C by Saturday evening. Ensemble guidance suggests H7 winds reaching around 35-50kts across southwestern UT, with surface wind gusts approaching High Wind Warning criteria (50kts)...something that will need to be monitored in the coming days. 

As the closed low continues inland, this will bring a potent cold front through our forecast area later in the weekend. The main impacts with this front will be a quick transition to northwesterly winds, onset of widespread precipitation, potential for thunderstorms along the frontal boundary, and snow levels dropping to around 5500-6500ft. Winds could be quite gusty behind the front; ensemble guidance suggests a mean of around 20-30kts at 700-mb, though the GFS is a bit more anomalous, reaching 45kts over northern Utah. Precipitation chances will likely continue through Monday as the parent trough continues to shift over the western US….as well as the chances for afternoon thunderstorms given steeper lapse rates under the cold core. H7 temperatures will drop quite a bit with this trough, down to around -6C to -9C.

There is still a lot of uncertainty regarding the timing of the cold front. This could move through as early as late Saturday evening (21% of ensemble members) or as late as Sunday evening (another 21%). The most likely solution is Sunday morning to around mid day. 

.AVIATION…KSLC…Northwesterly flow will continue, with gusts to 20kts possible mainly during the afternoon. Light, southeasterly flow is expected around 09-10z. VFR conditions will prevail.

.REST OF UTAH AND SOUTHWEST WYOMING…Northerly to northwesterly winds will prevail through the afternoon and evening across the area, becoming gusty to around 20-25kts, especially across eastern areas. These northerly winds will weaken, becoming light and diurnally-driven overnight. VFR conditions will prevail.

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