https://www.sfgate.com/weather/article/ ... 420325.php
A major warmup is on the forecast for the Bay Area this week, with temperatures projected to climb as high as the upper 90s and low 100s by Wednesday and Thursday. That’s about 10 to 15 degrees above average for this time of year, Rick Canepa, a meteorologist for the National Weather Service, told SFGATE on Sunday afternoon.
“Very recently, the forecast weather models have been kind of jumpy,” he said over the phone. “Just a couple of days ago, we were thinking there was going to be rain, and now that’s totally shifted gears.”
Residual tropical moisture from Hurricane Marie and a mid-latitude low pressure system to the north are joining forces to kick off the warming trend starting Sunday, he said, causing a ridge of high pressure to redevelop and strengthen over Northern California. If more energy is involved with the low pressure system arriving from the north, temperatures could soar even higher, but if the high pressure ridge isn’t as strong as expected, projected highs could drop by a few degrees.
“It’s a bit of an unknown,” Canepa said.
For now, temperatures are expected to reach the upper 80s and low 90s on Labor Day, with similar conditions to Sunday afternoon. Highs will be slightly lower along the coastline, reaching the upper 70s to low 80s in cities like San Francisco and Half Moon Bay.
“Once you get further inland, temperatures will warm up quite rapidly,” Canepa said. “It will be hot again inland Tuesday as well.”
Wednesday is when triple-digit temperatures are forecast to arrive in the North Bay and South Bay, with projected highs of 102 in Concord, 99 in Livermore, 94 in Santa Rosa, and 96 in Kentfield, according to Canepa.
Meteorologists are looking at a moderate to major risk of heat-related illness, but are waiting to issue any official guidance until the forecast comes into clearer focus. For now, the weather service is advising people to stay hydrated and avoid direct exposure to sunlight during the hottest parts of the day.
A beach hazards statement remains in effect through Monday evening. People going out to the coast to cool off throughout the holiday weekend are encouraged to avoid standing on jetties, rocks and piers due to breaking waves of up to 10 feet high. “Never turn your back on the ocean,” Canepa said.
The good news is that some respite is expected by Friday, when northwest winds are likely to cool temperatures down to normal again.
“It’s an interesting contrast with the jump in sea surface temperatures caused by atmospheric pressure, which has recently kept temperatures on the cool side,” Canepa said, noting record-breaking rainfall in Santa Rosa and San Rafael. “We’re due to turn it back around and above normal if the current forecast plays out.”
