FXUS65 KSLC 222145 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 345 PM MDT Mon Apr 22 2024 .SYNOPSIS...Warming trend temperatures associated with high pressure are expected Tuesday into Wednesday before a cooler and more stormy pattern develops for the latter part of the week. && .SHORT TERM (Through 12z Wednesday)...Surface obs and MSLP analysis indicate the remnants of a weak boundary over central Utah at this time, the driver for slightly cooler temps across the north today vs. yesterday. Mean ridging encompassing much of the Great Basin will further build into the region over the next 24-36 hours lifting the aforementioned boundary over the northern third of the state this evening while providing a subtle W-E zone of moisture convergence and isolated shallow convection potential. Buildups tracking in from Nevada more than anything, but a mountain sprinkle is possible. This zone will remain established over the north through Tuesday owing to slightly higher probs for convection, again largely isolated, with little if any rainfall potential. With the aforementioned high pressure gradually orienting overhead, northern areas will once again see an upward tick of temperatures with only periodic cloud cover associated with aforementioned convective buildups. Changes to come in the long term portion of the forecast however... .LONG TERM (After 12Z Wednesday)...Long term period starts off with a ridge axis shifting east into the Great Plains, a closed low approaching the lower California coast, and the local forecast placed within enhanced southwesterly flow between these two features. With this, mild H7 temps will promote afternoon high temperatures around 7 to 15 degrees above climatological normal, and will see some modestly gusty conditions (gusts generally ~20-30 mph) develop across portions of southern and western Utah. Widespread precipitation isn't expected, but combination of a bit more synoptic support from the aforementioned low, diurnal heating, and sufficient lingering moisture will likely yield some isolated to scattered afternoon/evening showers across southwest Wyoming and northern Utah (generally north of the I-80 corridor). On Thursday, guidance continues to show decent consensus that the closed low will lift through the forecast region, opening up as it begins to interact/phase with the northern stream. With the exception of portions of far southern Utah, the combination of a bit more moisture and widespread synoptic forcing will bring about increasing precipitation chances through the morning, with showers becoming more widespread through the afternoon. Generally, guidance continues to favor the northern third of the forecast region in terms of better QPF amounts Thursday. Additionally, there is some signal for a bit of destabilization (likely on the order of some pockets of CAPE up to 200 J/kg or so), so a few thunderstorms will be a possibility. Given the lower latitude origin of the system, H7 temperatures won't cool too much, so snow levels largely remain above 8.5kft to around 9.0kft. Pattern remains active moving into Friday, as while Thursday's trough continues to depart to the northeast, a more potent northern stream trough begins to dig in from the northwest. Much of the forecast region will be placed in the divergent exit region of approaching ~100+ kt upper jet, which in combination with a lower level cold front gradually working through during the day will yield widespread precipitation more or less areawide. Still some uncertainty on how long the initial shortwave lingers, but most guidance suggests enough trailing energy to keep cooler post frontal shower activity maintained on into Saturday. Given the colder origins of this system, will see snow levels fall generally into the 7.5kft to 8.5kft range Friday, and continue down to around 7.0kft to 7.5kft by Saturday. Surface temperatures across the region will also fall as the colder airmass sinks in, with afternoon highs Friday and Saturday shifting downward generally to around 5 to 15 degrees below climatological normal. Uncertainty remains a bit high Sunday onward into early next week given differences in how guidance resolves the evolution of the flow. Individual deterministic guidance depiction ranges from zonal flow within broad longwave troughing across much of the CONUS to weak shortwave or weak ridge slipping through. Ensemble members seem to be similarly weighted with no clear signal really favored. As a result, kept NBM PoPs which carry isolated to scattered diurnal activity from central Utah northward Sunday and Monday, and NBM temps which impart a warming trend as the colder H7 temperatures exit the region. && .AVIATION...KSLC...VFR conditions will persist across the KSLC terminal through the period. Conditions will remain dry with a few mid and high clouds. Winds will likely remain light and out of the north. There is about a 30% chance they briefly go to a light southerly flow overnight. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist for the entire airspace as dry conditions with a some mid to high clouds continue. Winds will be light and variable across central and northern Utah with some gusty westerly winds across southern Utah easing overnight. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Merrill/Warthen/Mahan For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity