Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
073 FXUS65 KSLC 141003 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 403 AM MDT Tue May 14 2024 .SYNOPSIS...A series of storm systems will impact Utah and southwest Wyoming through Wednesday, bringing less warm and more unsettled conditions. High pressure will return Thursday and Friday, bringing a warming and drying trend. Unsettled conditions are expected to return by early next week. && .SHORT TERM (Through 12Z Thursday)...The grazing trough that pushed a cold front into northern Utah yesterday has moved east into Wyoming this morning as a second wave slides into Idaho. The associated cold front is stalled near a KMLF-KEEO line, where some showers are persisting overnight. In taking a look at satellite data and observations, the broader area of echoes east of I-15 does not have cloud cover associated with it and is likely chaff, but the echoes over eastern Utah do appear to be associated with light showers. CAMs indicate this shower activity will die off over the next few hours, but have been overly bullish in ending the shower activity thus far. As the second shortwave grazes northern Utah during the day today, the cold front will make its way southward, likely moving into Arizona this evening. The passage of the trough is expected to bring another round of showers to areas near the Utah/Idaho border, but also to areas along the front over central and southern Utah, particularly over the higher terrain. Gusty downburst winds will be the main threat with any storms that develop given the atmospheric profile, but there is also a low chance of some small hail. As the second wave exits late tonight into early Wednesday, one last trailing wave will approach the area, sliding northwest to southeast across Utah. Thus, the area will see afternoon convection once again, with the track of this wave bringing the best coverage to areas east of I-15. These systems and the associated front will also bring a small amount of cooling to Utah and southwest Wyoming, though maxes will still average 5F above seasonal normals for Wednesday, the "coolest" day of the week. .LONG TERM (After 12Z Thursday)...Big picture of the long term forecast period is that warmer and largely dry conditions will prevail across Utah and southwest Wyoming through at least early next week. Under the influence of the eastern periphery of an offshore ridge, high pressure will remain the dominant weather feature over the area which will help to bring continued above normal temperatures and dry conditions throughout. This will be the trend through at least Saturday, with the forecast becoming a bit more uncertain thereafter. There continues to be a large amount of uncertainty revolving around the potential influence of a trough over the forecast area, however, models have been trending toward the eastern periphery of a ridge remaining the dominant weather feature until the pattern can transition toward more of a mean trough in the West as opposed to a mean ridge with troughs attempting to translate through the mean flow. That said, ensemble means from the EPS and GEFS paint a similar picture as a trough attempts to dive out of southern Canada and into the northern U.S. Rockies. The biggest uncertainty right now appears to revolve around the overall depth of this trough, with the EPS favoring a much more shallow feature than the GEFS. Through at least Sunday, ensemble consensus (including the Canadian ensemble) leans toward a shallower trough that would dictate only slight cooling over the northern half of the forecast area. It`s not until early to middle of next week when models begin favoring a mean trough developing over the western U.S., favoring cooler and wetter conditions over the forecast area. At this time, not seeing any potential for incredibly significant weather impacts. && .AVIATION...KSLC...Minimal weather concerns are forecast for the KSLC terminal through the valid TAF period. Predominantly southerly flow, with periods of light and variable, are expected through the morning hours. Northerly flow will return around 17Z and persist through the day under mid and upper level cloud cover. .Rest of Utah and Southwest Wyoming...VFR conditions are expected across the remainder of Utah and southwest Wyoming. Another round of isolated to scattered showers is expected in the forecast area, with a focus across the southern half of Utah and the UT/ID border region. Gusty and erratic outflow winds in excess of 30kts will be possible with passing showers. Otherwise, winds will favor a north to northwesterly direction. && .FIRE WEATHER...The cold front that moved through the area yesterday has now stalled over central Utah. As a second storm system grazes northern Utah later today, the front will be nudged southward, moving into Arizona Tuesday evening. The boundary will act as a focus for afternoon and early evening showers and thunderstorms, with the best coverage over the higher terrain. There is a chance of gusty downburst winds with any storms that develop. One last week storm system will move through the area Wednesday, bringing some additional convection. However, overall coverage will be less than yesterday and today and should primarily be focused over higher terrain areas east of I-15. High pressure will bring a drying and warming trend through at least Friday, with a dry cold front bringing slight cooling to northern Utah on Saturday. With the ridge having weakened with this front, a more unsettled pattern is expected to return for early next week. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ SHORT TERM/FIRE WEATHER...Traphagan LONG TERM/AVIATION...Webber For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity