Dry and quiet weather will continue through the end of the week into the weekend. Temperatures across the middle of the week will hover around seasonal normals, before hot, above normal temperatures arrive from Friday through Monday. Resultant widespread Major HeatRisk is forecast across the weekend ahead, alongside elevated fire weather concerns.

Dangerous heat forecast for the weekend and beyond

Discussion (Today through Friday)

An upper level ridge over the desert Southwest will continue to back build westward through the middle portions of the week ahead. This will lead to temperatures warming to near to slightly above normal values today through Thursday.

Resultant HeatRisk values will remain generally minor today and Wednesday, with pockets of moderate cropping up on Thursday within the Valley.

By Friday, ensemble guidance is in generally good agreement that the aforementioned upper level ridge will begin to build northwestward over interior NorCal. This will in turn result in the first day of well above normal temperatures and widespread Moderate HeatRisk for the region on Friday.

Otherwise, given the large scale ridging aloft, quiet and dry weather will prevail through the remainder of the week ahead.

Extended Discussion (Saturday through Tuesday)

Cluster analysis continues to hold onto the large scale anomalous ridging over the region through the weekend and into early next week. Resultant high and low temperatures from Saturday through Monday look to remain well above normal. Probabilities of exceeding 100F are in the 80-100% range within the Valley over the weekend, with still a 70-90% chance on Monday. Chances for exceeding 110F are lower (30-60%), but still nonzero, especially across the northern Sacramento Valley.

Major Heat Risk on Saturday and Sunday, July 15-16, 2023.

Latest HeatRisk continues to paint areas of widespread Major values, with some pockets of Extreme for Saturday and Sunday, with a slight reduction to widespread Moderate for Monday.

This will be due in part to the hot afternoon high temperatures, but also from persistently warm overnight low temperatures as well. Probabilities of overnight lows exceeding 70F are in the 75-95% range from the foothills to the northern Sacramento Valley from Saturday morning through Monday morning.

Accompanying this hot weather across the weekend and early next week will be generally drying conditions as well. Forecast minimum RH values in the teens are anticipated throughout the Valley and foothills.

Fire safety

While winds are only expected to be locally breezy, with these very dry conditions, elevated fire weather conditions will be possible over the weekend.

With warming temperatures, mountain snowmelt continues to occur across the region. This means that area waterways are still running fast and cold. Be sure to practice cold water safety and remember to wear a life jacket if engaging in water recreation activities.