Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
965 FXUS65 KSLC 092137 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 337 PM MDT Sun Mar 9 2025 .SYNOPSIS...High pressure over the area will shift east and flatten for the early part of the week. An upper level low will pass well south of the Utah/Arizona border Tuesday, keeping the majority of the Beehive State dry. The next significant winter storm will impact much of the state beginning Wednesday night and continue into at least Friday. && .SHORT TERM (THROUGH 00Z WEDNESDAY)...High pressure over Utah this afternoon will continue to maintain dry and stable conditions over the area. This high pressure will shift east and flatten tonight into tomorrow, resulting in increasing west to southwesterly flow aloft. This will enhance mixing for tomorrow. As such, even though H7 temperature will trend slightly cooler, surface temperatures are expected to be warmer, with most valleys forecast to be in the upper 50s to 60s for the max. The NBM has an 87% chance of reaching 60F or higher at SLC tomorrow. On Tuesday, the chance increases to 97%. However, clouds are expected to increase into the area by then, as a storm system tracks into the desert southwest, so will see if this is enough to hold temperatures down a bit. The storm itself is still forecast to remain south of Utah, with minimal impact to the area. .LONG TERM (After 00Z Wednesday/6PM Tuesday)...A potent trough will bring statewide mountain snow, gusty winds, and the potential for impactful valley snow between late Wednesday and Friday. Key points are as follows: * Southwesterly winds will begin to increase on Wednesday, becoming very gusty in the afternoon/evening across western valleys. Moisture will overspread the area, with heavy mountain snow expected beginning early Thursday for favored areas such as Brian Head. * A potent cold front will bring heavy precipitation, a transition to northwesterly flow, and plummeting snow levels below most valley floors by Thursday night. * Lighter mountain/valley snow will continue overnight and into Friday, with northwest-flow favored higher terrain seeing additional accumulations. Western valleys will see increasing south to southwesterly winds on Wednesday, with the NBM 24-hour max gust well exceeding Wind Advisory criteria and even approaching High Wind Warning criteria (30-40% chance). In addition to these prone areas (western Millard and Juab Counties), we`ll have to monitor the potential for these winds in the Tooele/Rush Valleys on Wednesday, and then across eastern valleys on Thursday and even Friday. Blowing dust and haze may also become a concern, particularly across western Utah. Winds could be locally maximized near high-based showers, as we saw ahead of the most recent storm system. In this pre-frontal environment, a surge of moisture will result in precipitation quickly ramping up on Wednesday and Wednesday night, with mountain snow potentially becoming quite heavy by Thursday morning. Snow levels will initially be fairly high, around 6000- 7000ft across the state. As mentioned in the bullets above, a strong cold front will make its way across Utah and southwest Wyoming likely between mid-day Thursday and Friday morning. Temperatures at 700-mb will quickly drop from around -4C to around -14C, resulting in high confidence in most valleys transitioning to snow sometime between Thursday evening and early Friday morning. Given the nature of this front, we`ll have to monitor the chances for snow squalls/flash freezes moving forward. To summarize, this storm system will bring beneficial snowfall to all of Utah`s mountains. While snow amounts aren`t anything terribly anomalous (even across valleys), what`s potentially more impressive is the anomalous cold this system will bring so quickly...at least compared to most other storms this winter. && .AVIATION...KSLC...Clear skies will continue with light southeast winds into Monday afternoon. High clouds will build in for the afternoon, with winds transitioning to northwest around 20Z. .REST OF UTAH AND SOUTHWEST WYOMING...Clear skies will last through much of the TAF period, with high clouds building in early in the afternoon Monday. Relatively light winds will last into Monday, with gusts around 20 knots from 18-01Z for southwest Utah and southwest Wyoming. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Cheng/Cunningham/Wilson For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity