Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
157 FXUS65 KSLC 060954 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 354 AM MDT Sun Oct 6 2024 .SYNOPSIS...High pressure will remain the dominant weather feature through late week bringing warm and mainly dry conditions. Temperatures will trend a bit warmer each day through Thursday, remaining well above normal for early October. && .SHORT TERM (THROUGH 12Z TUESDAY)...High pressure continues to build over the area this morning, although a very weak disturbance is noted cutting into the ridge. This disturbance is helping to draw some midlevel moisture into the area, as some midlevel clouds exist central NV currently. Some CAMs are hinting at very isolated, high- based showers over portions of southern through west-central Utah this afternoon. These will produce very little to no precipitation, although can not rule out some gusty and erratic outflow winds. Otherwise, a subtle warmup in the already above normal temperatures is expected for today. Smoke from the Yellow Lake fire will likely be an issue again for the Uinta Basin. However, lighter winds today may aid in decreased fire activity. Moisture continues to increase tomorrow with HREF ensemble mean PWATs rising to between 0.4-0.6 inches across much of the area. This will bring increased coverage of high-based showers to the area, and all CAMs are showing modest simulated reflectivities over most mountain areas. Ensemble mean SBCAPE values remain very low, although ensemble maxes reach 100-250 J/kg. Have raised chances of showers to 10-20% over the mountains, but thunderstorm chances remain minimal. .LONG TERM (After 12Z/6AM Tuesday)...The start of the period will feature a ridge of pressure over the eastern Great Basin, with the ridge axis sliding slowly slowly eastward as a trough of low pressure drops into southern California. This pattern will facilitate a southerly flow with increasing moisture in the mid- to upper-levels. While mean CAPE values remain modest at best, generally below 200 J/kg, moisture combined with divergent flow should lead to isolated convection on Tuesday, primarily across higher terrain. Given dry air in the lower levels of the atmosphere, the potential will exist for dry microburst winds. With ridge amplification and a dry southwest flow aloft, Wednesday and Thursday will be dry and warm, with high temperature expected to be 10 to 15 degrees above normal. A potential pattern change is in store for late Friday through the weekend, though a tremendous amount of spread in ensemble solutions indicates low confidence in any given scenario. Roughly 35 percent of members indicate a broad trough of low pressure sweeping through the Great Basin on Saturday, with 30 percent indicating a much shallower trough moving through region. Other ensemble solutions indicate a flat ridge of high pressure over the region with a trough remaining off the Pacific Coast. The Deeper trough scenario would suggest the potential for stronger winds and potentially critical fire weather conditions on Friday, though relative humidities look marginal, especially across northern Utah. At this time, none of the scenarios indicate any significant precipitation. High temperatures should be at or below normal by Sunday. && .AVIATION...KSLC...VFR conditions will prevail through the TAF period. Light southeast drainage winds will transition to northwest winds around 18Z, then back to southeast drainage winds around 03Z. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail through the TAF period, with the exception of over northeast Utah, where wildfire smoke will reduce visibilities. Winds will be generally light and terrain driven, except over northeast Utah and extreme southwest Wyoming, where a moderate west to northwest flow aloft will mix down to the surface this afternoon. && .FIRE WEATHER...High pressure will be in place over Utah through at least the middle of the week, maintaining warm and generally dry conditions. Midlevel moisture will gradually spread into the area through Tuesday. Very isolated high-based showers producing very little or no precipitation will be possible across southern through west-central Utah today. Cannot rule out briefly erratic and gusty winds underneath some of the showers. These showers will spread northward tomorrow while gradually increasing in coverage through Tuesday. Towards the end of the week, increasing southwesterly flow becomes more likely as the high pressure shifts east. These winds will have the potential of bringing critical fire weather conditions to localized areas where humidities are low enough, although currently, forecast minimum relative humidities for many areas are above the 15% threshold. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Cheng/Barjenbruch For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity