Area Forecast Discussion
Issued by NWS Salt Lake City, UT
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Issued by NWS Salt Lake City, UT
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-- Discussion containing changed information from previous version are highlighted. --533 FXUS65 KSLC 221003 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 403 AM MDT Sun Sep 22 2024 .SYNOPSIS...-- Changed Discussion --Seasonable temperatures will continue, with a few isolated showers possible across higher terrain of eastern Utah Sunday afternoon. A weak, dry cold front will graze the area Monday, with high pressure building thereafter.-- End Changed Discussion --&& .SHORT TERM (Through 12Z/6AM Tuesday)...-- Changed Discussion --Shortwave ridging will continue to build across the area today, producing largely quiescent conditions with high temperatures a smidge below normal. Most areas will see mostly sunny skies, though expect some cumulus build ups on higher terrain this afternoon. Given residual moisture in some areas, a few isolated showers are even possible over the higher terrain of eastern Utah, including near Boulder Mountain northwards to the high Uinta Mountains. A weak disturbance moving in from the north will graze our area on Monday on the downstream end of a building western US ridge, though impacts will remain minimal. Breezy conditions are possible across Uinta Co., WY, but otherwise, temperatures will be largely unchanged and precipitation chances are nearly zero. Enjoy the beautiful weather as we transition into fall! .LONG TERM (After 12Z/6AM Tuesday)...Ensemble and deterministic guidance is in excellent agreement through Friday, lending a high degree of confidence in the forecast through that timeframe. Model consensus depicts a ridge building across the PacNW at the beginning of the period on Tuesday morning, with downstream height rises underway across Utah and SW Wyoming. This ridge will build across our area on Wednesday. The emergence of this pattern will ensure dry, stable conditions with steadily warming temperatures. While the ridge will weaken through Friday, positive height anomalies/general ridging will remain in place across the area as represented by ensemble means, bringing mainly clear, cool nights and warm days, with high temperatures 5F-15F above normal -- a very tranquil start to the beginning of Autumn indeed! Currently, there is a 10-20% chance of reaching 90F at SLC Thursday and Friday, underscoring the warm afternoons. Heading into next weekend, the solution space does begin to diverge a bit regarding the large-scale pattern evolution. Two scenarios begin to emerge: the first maintains ridging over the area, with a resultant continuation of warm, tranquil conditions. The second scenario allows for a more amplified trough passage to our north, which would tend to favor a largely dry cold frontal passage across the north, along with periods of breezy conditions. Even at this juncture, less than 10% of the solution space generates QPF, so prospects for precipitation appear quite low through the period.-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --KSLC...Easterly pressure gradient in place early this morning will result in largely variable winds (with a general, dominant southerly component) before typical lake breeze/afternoon valley circulation forces a wind shift to the NW. Latest guidance suggests this will occur around 17Z. Downvalley/drainage SSE flow is expected to develop between 03-04Z this evening. Otherwise, VFR conditions once again expected through the period. .REST OF UTAH AND SOUTHWEST WYOMING...Upper low will continue to move east of the area on Sunday. Just enough moisture will linger to promote the development of terrain-based cumulus with isolated showers this afternoon. Otherwise, VFR conditions are expected through the period.-- End Changed Discussion --&& .FIRE WEATHER...-- Changed Discussion --A brief period of high pressure will build today as the low pressure system continues to move eastward over CO. Lingering moisture could help produce a few showers over higher terrain of eastern Utah Sunday afternoon, but overall expect a trend towards drier conditions. A weak, dry cold front will slide across northeastern areas on Monday, bringing a slight increase in wind gusts to 15-25 mph over higher terrain in northern/eastern Utah. Critical fire weather conditions are not expected. Stronger high pressure will then build through the week, producing drier conditions for the near future. RH recoveries are likely to worsen, becoming marginal to poor by midweek across much of the area.-- End Changed Discussion --&& .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Cunningham/ADeSmet For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity