Sacramento and the region face latest excessive heat watch. Here’s when it takes effect

UPDATE: Northern California faces dangerous heat. Here’s where it will be hottest and for how long

An excessive heat watch will go into effect in the Sacramento Valley and other areas of Northern California in the coming week, with the National Weather Service warning of “widespread moderate to locally high” risks.

The watch called by the Weather Service begins at 11 a.m. Tuesday and is expected to last through 8 p.m. Friday.

“Stay hydrated and vigilant,” National Oceanic and Atmospheric Administration spokesperson Scott Rowe said. “People should pull down the shades in daylight hours, and avoid caffeine and alcohol.”

Meteorologists will determine in the next 12 to 24 hours if the watch will be elevated to a warning, Rowe said.

Regional highs are expected to range from 100 to 109 degrees in the Valley and 96 to 106 in the foothills. Overnight lows in the Valley will dip only to about 65 to 75 degrees, and to 70 to 80 in the foothills.

Due to those relatively high nightly temperatures, there will be poor overnight recovery that is only going to compound the situation. It means there will be more stress on the body, Rowe said.

People working or participating in outdoor activities are at risk for heat-related illness, according to the Weather Service. They advise people to drink plenty of fluids, monitor weather warnings for updates, stay in air-conditioned rooms, and check on neighbors and relatives throughout heat waves.

“Heat stroke is a medical emergency and you need to call 911 if someone is exhibiting signs,” Rowe said.

The alert again warns people to never leave children or pets unattended in vehicles. Car interiors can reach lethal temperatures in minutes.

Sacramento County in recent days announced it has opened cooling centers for this heat wave.

The centers will be open to the public from 2 p.m. to 8 p.m. Sunday and 8 a.m. to 4 p.m. Monday to Friday. On weekdays, centers will stay open longer for weather respite for the homeless and those in need, extending hours from 4 p.m. to 8 p.m.

Areas that will be affected include:

• Carquinez Strait and Delta

• Central Sacramento Valley

• Motherlode

• Mountains, southwestern Shasta County to western Colusa County

• Northeast foothills, Sacramento Valley

• Northern Sacramento Valley

• Northern San Joaquin Valley

• Southern Sacramento Valley