Utah is bracing for a significant warming trend and heightened fire risks starting early next week, as the National Weather Service warns that temperatures could climb to 100 degrees in some valleys. The shift follows a mostly dry weekend, bringing concerns over dry lightning and erratic winds across the state.
According to an area forecast discussion issued by the National Weather Service in Salt Lake City on July 3, a zonal flow pattern is establishing over Utah. This pattern is allowing drier air to spread into the region, following the dissipation of convection that occurred earlier in the week over northern Utah and southwest Wyoming.
While much of the weekend will remain mostly dry with clouds gradually clearing overnight, the weather pattern is expected to shift by Monday. Forecasters noted that moisture levels are projected to peak on Monday, though even at this peak, widespread significant rainfall is unlikely due to the short duration of moisture advection.
The heat is expected to intensify as the week progresses. The National Weather Service reported that temperatures will likely climb to approximately five degrees above normal by early next week. There is a 30% chance that Salt Lake City could reach its first 100-degree day of the year.
In southern portions of the state, the heat may be even more extreme. Forecasters expect lower Washington County and the Lake Powell area to see temperatures ranging between 102 and 107 degrees throughout the week. As a result, a Moderate HeatRisk is expected to become widespread across Utah valleys during the middle to latter portion of next week, with some pockets potentially reaching Major HeatRisk levels late in the week.
The combination of rising heat and shifting winds has prompted specific fire weather concerns. The National Weather Service indicated that while a weak westerly flow will yield lighter winds this weekend, an increase in mid-level moisture on Monday could trigger scattered afternoon convection, primarily near higher terrain.
On Monday afternoon, elevated southwesterly winds are expected, which may lead to locally critical fire weather conditions, particularly across portions of southern Utah. The primary concerns for any storms that develop during the early part of the week include dry lightning strikes and gusty, erratic outflow winds.
The transition in weather will be marked by changing wind patterns and moisture levels. On Sunday, high pressure is forecast to establish itself near the Four Corners area, driving southerly flow that will spread midlevel moisture into the region. However, much of this moisture is expected to remain over Arizona and New Mexico.
A weak disturbance from the remnants of an eastern Pacific tropical system is also expected to move across California and western Nevada, contributing additional moisture to the area. Despite this, National Weather Service data shows that even at peak levels, precipitable water (PWAT) values are expected to remain low, ranging between 0.6 and 0.75 inches across much of the forecast area.
As the week continues, the weather pattern is expected to trend toward even drier conditions. High pressure will shift westward through midweek, reintroducing a drier westerly flow to Utah. This shift is expected to decrease the coverage of afternoon convection by Tuesday and Wednesday.
By the end of the week, the National Weather Service anticipates gradually decreasing relative humidity and increasingly poor overnight recoveries across the state as a very dry airmass begins to build into the region.
