Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
443 FXUS65 KSLC 132132 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 332 PM MDT Sat Jul 13 2024 .SYNOPSIS...A strong area of high pressure will continue to bring very hot and dry conditions to the region through this evening. Moisture will continue to spread into southern Utah today, and then increase across the entire area to start the upcoming week, bringing with it some shower and thunderstorm activity. The ridge is then expected to build back in for the latter part of the upcoming week. && .SHORT TERM (Through 12Z/6AM Monday)...High pressure remains in place over the region this afternoon, with the ridge axis currently situated near the Utah/Colorado border. This has put Utah and southwest Wyoming under a southerly flow aloft, which is drawing moisture and instability northward. This has led to the development of showers and thunderstorms this afternoon, primarily focused over the higher terrain. Given this moisture has been initially mid and high based and the rather hot and dry antecedent conditions, seeing little in the way of rainfall with areas of strong and gusty microburst winds. This combination has resulted in high fire danger over southern Utah, with a Red Flag Warning in effect. As the moisture continues to increase and spread northward tomorrow, will see convection increase in coverage and become more widespread across the area. Though lower levels will become more moist over southern Utah, extended the RFW for going zones and also expanded northward to the remainder of the zones in our responsibility just because of how hot and dry things have been. Under the ridge, very hot temperatures continue, with most areas seeing temperatures around 10F above seasonal normals. However, with the increase in moisture will see high temperatures drop a few degrees tomorrow areawide, and this will be enough to decrease HeatRisk values into the orange (moderate) range for most areas tomorrow. So while impactful, especially for sensitive groups, the danger from the heat looks to decline a bit tomorrow so have not extended the going Excessive Heat Warnings at this time. .LONG TERM (After 12Z/6AM Monday), Issued 432 AM MDT...At the start of the long- term period on Monday, the ridge of high pressure that brought record- breaking temperatures to our area will have shifted eastward, providing some relief from the heat, especially as the ridge weakens a bit on Monday. With this weakening/flattening of the ridge, this will allow some drier air to filter in from the west. However, mid- level moisture is still expected to hang around through at least Day 7, providing daily chances for showers and thunderstorms especially across southern areas and across higher terrain. The low levels will remain fairly dry, deterring flash flood chances unless storms are able to train or back-build. Gusty and erratic outflow winds will continue to be a threat near any developing showers. It`s worth noting that portions of northern UT (such as the Wasatch Front) may remain quite dry during this time, with only increasing cloud cover during the afternoons. Heading into mid-week, the ridge will regress and begin to build once again right over Utah. This will likely bring a slight increase in temperatures, though current guidance isn`t suggesting a heatwave like this past week. Moisture will increase once again heading towards the weekend, with increasing coverage of showers and thunderstorms across much of the area. && .AVIATION...KSLC...Light rain showers and gusty, erratic outflow winds will be possible through the evening, with showers diminishing around 06Z. Light northwest winds will prevail through around 03Z, with a transition to southeast winds around then. Isolated showers and thunderstorms are likely from around 20Z through the evening. .REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and thunderstorms capable of gusty, erratic outflow winds will diminish around 06Z. Light winds with dry conditions are likely through around 18Z. Showers and thunderstorms will build around 19Z and last through the evening. && .FIRE WEATHER...Record heat will remain over the area this afternoon before conditions becoming slightly less hot on Sunday, with the less hot temperatures continuing during the early part of the week. High based moisture has made its way into the area, resulting in showers and thunderstorms that are producing strong gusty winds and little rainfall, initially focused over the higher terrain, particularly over central and southern Utah. Coverage of showers and thunderstorms will increase tomorrow and spread northward as the moisture and instability continue to move back in. Given the recent very hot and dry conditions ahead of this expected scattered thunderstorm activity, have extended the going Red Flag Warning through tomorrow evening and have added the remainder of the zones in our area to the RFW for tomorrow. The threat of showers and thunderstorms will continue through the early part of the week, though storms will become wetter in nature and temperatures will continue to become less hot. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Excessive Heat Warning until midnight MDT tonight for UTZ101>107- 114>116-118>124-128>131. Red Flag Warning from noon to 9 PM MDT Sunday for UTZ478>484-488- 489-494. Red Flag Warning until 9 PM MDT Sunday for UTZ492-493-495>498. WY...None. && $$ SHORT TERM/FIRE WEATHER...Traphagan LONG TERM...Cunningham AVIATION...Wilson For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity