Heat and humidity envelop Bay Area and Central Coast, with hotter tempertures on the way
Muggy conditions prevailed across the Bay Area and Central Coast on Monday, as monsoonal moisture from the southwestern U.S. and northwestern Mexico continued to envelop the region, with hotter temperatures on the way, forecasters said.
The National Weather Service said in its daily forecast summary for the region on Monday clouds and humidity are clearing out and ushering in above-average heat. A heat advisory will be in effect from 10 a.m. to 10 p.m. on Tuesday for North Bay interior mountains and valleys, the Santa Clara Valley and Eastern Hills, the East Bay hills and valleys, and the Northern Salinas Valley/Hollister Valley and Carmel Valley.
The NWS said the loss of cloud cover and the onset of full sunshine will bring temperatures into the mid-90s for inland locations around the Bay Area, and up to triple digits for some of the hottest area as well as for the Central Coast interior. Coastal locations will see temperatures in the mid-70s, while most areas will see at least 5 to 10 degrees above normal as a ridge of high pressure strengthens over the region.
For Monday, the Weather Service said there was still a 10% chance of dry thunderstorms and isolated showers. Despite that low probability, the NWS said with the added threat of lightning and gusty winds, these conditions still pose a fire risk. Even if it seems counterintuitive that the Bay Area's fire danger is rising, increased moisture and humidity won't do much in the way of fire prevention. Most rainfall will evaporate before reaching the ground, while dry lightning from thunderstorms can still reach the surface, NWS said. On top of that, vegetation is continuing to dry out, the Weather Service added.
The Weather Service said the heat shouldn't last long; strong onshore winds will arrive Tuesday afternoon and help cool the coast quickly. By Thursday, the Eastern Pacific trough that helped pump up the moisture earlier in the week will arrive, bringing a weak cold front and kicking off a late-week cooling trend.
In addition, a coastal flood advisory remained in effect until 4 a.m. Wednesday for areas including Point Reyes National Seashore, the San Francisco Peninsula, Northern and Southern Monterey Bay, and Big Sur area. For the shoreline surrounding San Francisco Bay and San Pablo Bay, the flood advisory was in effect until 4 a.m. on Thursday.
The NWS said inundation may reach up to 1.8 feet above normal due to higher-than-normal astronomical tides, leading to flooding of lots, parks, and roads. These tides are predicted to be lower than those in June, and the Weather Service estimates that areas not impacted in June can expect to be unaffected over the next week as well.
Marine conditions this week are set to become increasingly hazardous for boaters, especially over the outer coastal waters where fresh northerly winds and building seas are expected. Conditions will deteriorate further by midweek as northwest swells increase, the Weather Service said. There is also a small craft advisory in waters from Point Arena to Point Reyes until 3 p.m. on Wednesday.
Temperatures along the coast will remain relatively comfortable, with San Francisco, Half Moon Bay, Pacifica, Monterey, Santa Cruz, and other coastal communities expected to see their hottest temperatures in the 60's and 70s, with some lower 80s possible near bayside locations. Half Moon Bay and Pacifica in particular will remain cool throughout the week.
Around the bayshore and urban corridors, temperatures will be warmer than average, with San Jose, Oakland, Walnut Creek, Santa Rosa, and Napa generally seeing highs in the upper 70s to low 90s, with overnight lows into the 60s.
As usual, the hottest weather will be farther inland, with interior East Bay valleys, southern Salinas Valley, interior Monterey County, and interior portions of San Benito County climbing into the upper 90s and low 100s in some hotspots.
