175 FXUS65 KSLC 060329 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 929 PM MDT Sat Sep 5 2020 .UPDATE...Smoke from the California and Oregon fires has begun to work into far northern Utah this evening. Initially, this smoke will remain aloft early Sunday, with some deterioration of visibilities and air quality possible later in the day. If the smoke layer are somewhat opaque, look for high temperatures up north to come in a few degrees cooler than Saturday's readings. && .SYNOPSIS...High pressure will remain across the region through the weekend. A weak but dry cold front will cross the state Sunday, followed by a much stronger cold front early next week. Much colder temperatures are expected Tuesday and Wednesday. && .SHORT TERM (Through 12Z Tuesday)...The unusually strong upper high centered near the Utah/Nevada border will bring another day of near record to record highs across much of state into Monday. This high will shift west into Nevada late Sunday, bringing slightly cooler but still well above normal temperatures to northern Utah Monday. Record could still fall across the south, even with temperatures down a few degrees to begin the week. A longwave trough will continue to deepen across the northern and central Plains through the weekend. This will help to flatten the northeastern portion of the ridge and continue to increase the mid-level winds across Utah. Despite hot temperatures and nearly clear skies, gusty winds can be expected across a broad area of Utah Sunday afternoon and evening. Red Flag Warnings remain in effect for a significant portion of the state. Please review fire restrictions and best practices if venturing outdoors over the next few days as record temperatures, high Haines Index values, gusty winds and extremely critical fuels will present very elevated fire danger. A weak and dry cold front will cross the state Sunday. This will help to cool temperatures a bit across northern Utah but it will still be quite hot. The main show is Monday as a very fall-like front sets up. A digging, strong shortwave will round the western side of the previously mentioned longwave trough. Through continental...and thus associated with limited moisture...this shortwave trough will bring a much colder airmass in its wake, with 700mb temperatures falling to near -12C near the Montana/Canadian border by Monday evening. This trough will bring a strong cold front through Utah Monday into early Tuesday. Expect a substantial wind threat with this front...though right now looks to remain in a solid advisory range. Also of note...sufficient moisture for at least a period of snow will exist Monday night into Tuesday across portions of the Wasatch Mountains, western Uinta Mountains, Book Cliffs, Wasatch Plateau and central Utah mountains. While totals won't be significant, this will be the first snow for a lot of these locations. Anyone in the backcountry Monday night into Tuesday including campgrounds near Mirror Lake Highway should be prepared for winter-like conditions. As far as headlines go...an excessive heat warning remains in effect for lower Washington County and Zion National Park through Monday evening. A wide variety of Red Flag Warnings remain in effect through Monday evening as well. No winter or wind headlines are in effect...but this will need to be revisited over the next several shifts. .LONG TERM (After 12Z Tuesday)...The models are in general agreement in digging a vigorous shortwave trough through the area early Tuesday. The associated frontal boundary should be south of the Arizona border at the beginning of the Long Term period, with a tight northerly gradient in its wake resulting in breezy to windy conditions across most of the area. In addition strong easterly flow on the back side of this wave across southwest Wyoming into northern Utah may result in a favorable set-up for downslope winds along the northern Wasatch Front Tuesday morning. Some variance remains between model runs but will need to increase messaging about this potential high wind event if models lock in as the timeframe approaches. Sub-zero 700mb temperatures associated with this trough are expected Tuesday afternoon keeping max temps along the Wasatch Front, as well as most valley locations, confined to the 60s. With the cold airmass in place outlying locations including the Wasatch Back and perhaps the Cache Valley may be looking at a hard freeze Tuesday night. In the wake of this trough mid level ridging will gradually build back into the region allowing for a warming trend during the middle to latter portion of next week. && .AVIATION...The SLC terminal will see VFR conditions through the evening with clear skies. Light southeast will turn back to the northwest around 17Z-18Z Sunday. && .FIRE WEATHER...The next 7 days will be quite the range of forecast impacts. Expect near record to record heat through Monday across the state...with extremely low humidity and gusty winds. A very strong cold front will cross the state Monday into early Tuesday. With gusty winds and low humidities Sunday and Monday and this strong frontal passage...Red Flag Warnings are in effect for much of the state through Monday. Portions of southern and western Utah remain in a Fire Weather Watch for Monday as confidence is lower with the frontal timing impacting these areas prior to Monday night. This cold front will be very strong, bringing a temperature drop of around 20 degrees to much of the state. Expect strong winds with this front as well. For those higher terrain areas across the Wasatch, western Uintas, Bookcliffs and central Utah mountains, there is the potential for light snow accumulations, mainly above 8000 feet Monday night into Tuesday. Model guidance rapidly shifts to warmer temperatures and dry conditions by late in the week as high pressure builds back into the area. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Red Flag Warning from noon Sunday to 9 PM MDT Monday for UTZ484- 493-494-496. Red Flag Warning until 9 PM MDT Monday for UTZ479>483-488-489. Red Flag Warning from noon to 9 PM MDT Monday for UTZ478-492. Fire Weather Watch from Monday afternoon through Monday evening for UTZ495-497-498. Excessive Heat Warning until 9 PM MDT Monday for UTZ019. WY...&& $$ UPDATE/AVIATION...CONGER LONG TERM...SEAMAN SHORT TERM/FIRE WEATHER...KRUSE For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity For frequently asked questions about the Area Forecast Discussion visit... http://weather.gov/saltlakecity/general/afd_faqs.php