National Weather Service Warns Of High Temperatures For Memorial Day And Tuesday Bay City News Service FacebookTwitterEmail By Bay City News The National Weather Service is warning people -- especially the elderly and anyone with heat sensitivity -- to be cautious outdoors Monday and Tuesday, as temperatures are expected to be well above normal. The forecast is for temperatures reaching the upper 80s and 90s, possibly 100 in North and East Bay Valleys and Mountains, South Bay, Santa Cruz Mountains, Interior Monterey County and San Benito County. Elsewhere it will be cooler but still well above normal. Temperatures are expected Monday and Tuesday in the 70s and 80s around the shoreline of San Francisco Bay, and up to the mid-70s along the Sonoma and Marin coasts, San Mateo Coast and Monterey Bay Shoreline.