A steady warming trend is moving across the region due to building high pressure, according to the National Weather Service Salt Lake City. Heat Advisories have been issued for west-central through northwest Utah valleys, with temperatures expected to reach near or above 100 degrees in many valleys on Thursday.
The HeatRisk is currently in the Red (Major) category across many valley areas for Thursday. This heat risk is expected to become more confined to northern Utah by Friday. While temperatures may begin to cool in southern and central Utah as moisture surges into the area on Friday, temperatures in northern Utah are expected to remain near current levels or trend slightly warmer.
Monsoon moisture is expected to move back into Utah and southwest Wyoming late in the week and persist through at least early next week. This influx of moisture is projected to increase the threat of showers and thunderstorms capable of producing flash flooding. Currently, there is a Marginal Risk of Excessive Rainfall across southern Utah for Thursday and Friday, which is expected to spread through the rest of the forecast area for Saturday and Sunday.
Precipitable water (PWAT) values of approximately 0.8 inches are expected to increase to 1-1.1 inches across the area by Saturday afternoon. While moisture is increasing, dry air at the surface remains, with minimum relative humidity in the upper single digits to 20s across the entire area today.
Isolated afternoon thunderstorms may develop across the terrain and portions of eastern Utah. Due to dry surface conditions, these storms may struggle to produce wetting precipitation, instead resulting in frequent lightning and strong gusty outflow winds. By Friday afternoon, storms are expected to become more widespread across the state with increasing chances of wetting rain.
The high pressure is expected to slowly begin building westward again by the middle of next week. Depending on where the center of the high pressure ends up, the airmass may start to gradually dry during the second half of next week.
