Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
846 FXUS65 KSLC 102202 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 402 PM MDT Fri May 10 2024 .SYNOPSIS...An area of low pressure will remain over the region through Saturday, keeping showers and thunderstorms in the forecast for much of Utah. Higher pressure builds into the region through the weekend, bringing a warming and drying trend to Utah and southwest Wyoming into early next week. Thereafter, there is potential for a storm system to bring another round of wetter and cooler conditions to the region. && .SHORT TERM (Through 12Z/6AM Sunday)...An upper level low remains parked over the Great Basin region, bringing afternoon showers and thunderstorms over the area. Easterly winds aloft remain in place across northern Utah, however, previously strong winds in the typical downsloping areas have subsided. That said, with the easterly component to the wind lingering, should continue to see isolated wind gusts to around 30 mph near canyons on the northern Wasatch Front. With the low lingering over the region, general instability tied to the mid-level cold core will help to maintain showers and thunderstorms over Utah during the heating hours. As of this afternoon, the best instability and moisture availability exists across the southern half of Utah, and thus have been seeing the greatest coverage of showers and thunderstorms from Provo southward and the central mountain spine westward. With limited shear, developing showers have been very short lived with limited threat of hail, however, have been seeing isolate gusts of 30+ mph. These showers will decrease in coverage as we lose heating later this evening. Tomorrow, the low remains in place over the region, however, an eastward shift in the center of the low is expected. Another round of showers and thunderstorms are expected during the afternoon hours, with the primary focus being over the high terrain and downwind valley areas. Steering flow will gradually shift from a northeasterly flow (favoring southwest progression of storms) to a north to northwest flow by the mid-to-late afternoon (favoring south to southeast progression). The steering flow later tomorrow afternoon will begin to favor showers potentially progressing into more flash flood prone basins (i.e. Paria River Basin). While limited deep moisture availability exists (PWAT values less than 0.5 inches), can`t rule out an isolated shower producing moderate to heavy rainfall over a flashy drainage. .LONG TERM (After 12Z/6AM Sunday)...By the beginning of the long-term forecast period, the upper low will have already (finally!) made its way east into Colorado, while high pressure builds into the Great Basin. Utah will be under a north-northeast flow aloft for much of the day Sunday, with a warming and drying trend. That said, isolated to locally scattered convection remains possible across the higher terrain Sunday afternoon. Temperatures will return to above-normal values. Heading into Monday, zonal flow will develop over Utah as a shortwave trough grazes by to the north. This general pattern is reflected on the majority of global ensembles. A few showers remain possible with the trough skirting the area, otherwise temperatures will continue to trend warmer, given H7 temperatures ranging from +6 to +10C across Utah. Afternoon max surface temperatures will have a good chance of reaching 80F in many valley locales (a 64% chance at SLC per the NBM). Thereafter, the pattern starts to amplify with a ridge building off the West Coast. This would allow the next trough to drop into northern Utah some time on Tuesday or Tuesday night, bringing another round of precipitation along with cooler temperatures. Depending on how much the pattern amplifies, the trough could continue to impact Utah into Wednesday. For the latter part of the week, there is more uncertainty based on cluster analysis of ensemble solutions. The four clusters range from varying amplifications the upstream ridge to a more zonal pattern over the area. For the time being, the NBM is trending towards a generally dry pattern with a gradual warming trend through the end of the week. && .AVIATION...KSLC...Largely northerly to northeasterly winds will continue with gusts to 20kts through roughly 02z. Scattered showers this afternoon will be capable of producing gusty and erratic winds up to 25kts, with the most likely direction being out the east as showers move off the terrain. There is also a 15% chance of lightning. .REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and thunderstorms capable of producing gusty and erratic outflow winds will continue until roughly 01-03z, mainly across areas south of KENV-KOGD-KEVW and especially along higher terrain. Largely light winds are expected overnight, aside from some residual easterly canyon winds along the Wasatch Front with gusts to 25 mph at canyon entrances. && .FIRE WEATHER...An area of low pressure will linger over the southern half of Utah through tomorrow, keeping general instability draped over the area. Lower level moisture and instability will bring a higher likelihood of showers and thunderstorms over the high terrain from about the Salt Lake area southward through the Arizona border, with higher likelihood of wetting rains across the central and southern Utah mountains while the northern Utah mountains will have a much lower probability of wetting rains. Humidity will stay more moderated through this period, however, a warming and drying trend is expected through about Monday. Thereafter, there is potential for a cooler and wetter storm system to move through from Tuesday through Wednesday. That said, there remains some uncertainty on the details. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ SHORT TERM...Webber LONG TERM...Cheng AVIATION...Cunningham FIRE WEATHER...Webber For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity