Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
158 FXUS65 KSLC 030900 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 300 AM MDT Mon Jun 3 2024 .SYNOPSIS...A passing cold front will bring showers and thunderstorms to southwest Wyoming and northern Utah today. High pressure will build over the region beginning Tuesday, bringing dry and increasingly hot conditions through the end of the work week. && .SHORT TERM (Through 12Z Wednesday)...Seeing increasing high and mid-level clouds over northwest Utah this morning as a trough makes its way onshore over the Pacific Northwest. The main trough is expected to remain north of the area as it continues east, but an associated cold front will makes its way through northern Utah and southwest Wyoming during the day today. The associated upper jet is expected to graze northern Utah during this time, providing some more favorable instability. As a result, anticipating the development of an area of showers with some embedded thunderstorms for northern portions of the forecast area from about midday through the early evening, with the best coverage occurring for areas closer to the Utah/Idaho border. Associated cooling will be modest, about 5F for northern Utah compared to yesterday, bringing maxes back down to around seasonal normals as dry and unseasonably warm conditions continue over southern Utah. The system is on track to move east of the area by Tuesday morning as the associated cold front fizzles and moves south out of Utah. This will allow a broad Pacific ridge to spread eastward into Utah and southwest Wyoming, bringing dry conditions and increasingly hot conditions, described further in the long term discussion. .LONG TERM (After 12Z Wednesday)...Wednesday will be the first day in what will be several consecutive days of much warmer than normal temperatures. This will be as a powerful ridge slides inland from the eastern Pacific and builds into the western U.S. Southwest Wyoming and northern Utah will have the biggest increase in temperatures from Tuesday, with valley highs in the mid to upper 80s. Temperatures will get into the 90s for most southern Utah valleys, while lower Washington County will get into the 100s. Temperatures will warm further Thursday. There is good model agreement on the ridge axis positioned over Utah, extending far to the north. Valley high temperatures throughout northern Utah will range from the low 90s near the Idaho border to the mid 90s for the urban corridor. Mid to upper 90s are likely for many central valleys, and 100s are likely around Lake Powell and again for lower Washington County. An Excessive Heat Watch is in effect starting Thursday for both Lake Powell and lower Washington County. Along with the day temperatures, minimal cooling will happen overnight for those locations, with low temperatures in the low to mid 70s. The ridge axis will be nearly over Utah or slightly downstream Friday. Models are in general agreement on weak shortwave energy tracking into Utah within anticyclonic flow as the axis tracks east. Shortwave energy along with warming of the day will bring more clouds. Isolated showers and thunderstorms will almost exclusively stay around terrain with weak forcing, little moisture, and minimal wind shear. For temperatures, nearly identical numbers to Thursday are likely. Forecast highs and lows each day are almost all less 5F from record highs and lows throughout southwest Wyoming and Utah. The Excessive Heat Watch for those aforementioned locations is in effect through Friday. There is a bit more uncertainty into the weekend on details with the ridge. Most likely, it will stay in place, but not be as strong as late in the week. There is general agreement on shortwave energy rotating into Utah with isolated to scattered showers and thunderstorms, primarily near higher terrain. && .AVIATION...KSLC...Overcast conditions are likely by 17Z as a cold front and light rain build into northern Utah. Winds will transition to northwest around 17Z. Isolated showers from roughly 17-21Z will be capable of gusty, erratic outflow winds. Light rain is likely from roughly 21-00Z. VFR conditions will prevail, but ceilings will likely lower into MVFR range at times. Winds will transition to southeast around 00Z. Isolated showers will last through around 03Z. .REST OF UTAH AND SOUTHWEST WYOMING...A cold front with light rain will track into northwest Utah late in the morning. Overcast conditions, likely into MVFR range, and light rain is likely for much of northern Utah from roughly 20-00Z. Isolated showers will last through roughly 03Z, with clouds decreasing through the night. The front will push into southern Utah in the evening, bringing more clouds, but minimal precipitation. && .FIRE WEATHER...A Pacific Northwest storm system will bring a cold front across northern Utah during the day today, with good coverage of showers along with a few thunderstorms, primarily during the afternoon and early evening. The best chance of wetting rainfall will be for areas north of I-80. As the system exits the area, a Pacific ridge will build over the area through the work week, resulting in dry and increasingly hot conditions. Uncertainty increases as the weekend approaches, with a chance of a dry lightning threat due to increasing mid-level moisture. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Excessive Heat Watch from Thursday morning through Friday evening for UTZ123-131. WY...None. && $$ SHORT TERM/FIRE WEATHER...Traphagan LONG TERM/AVIATION...Wilson For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity