Updated Drift Smoke visible from Parrotts Ferry Bridge (file photo) A Red Flag Warning is now in effect until 6 PM Monday for the Southern Mother Lode (Tuolumne and Calaveras Counties below 3,000 feet) and the Northern San Joaquin Valley. According to the National Weather Service, gusty north to east wind, low humidity and unseasonably dry fuels will result in critical fire weather conditions over portions of the Central Valley and surrounding foothills below 2,000 feet. The strongest winds are expected through favorably oriented gaps and canyons in the surrounding foothills. Lighter wind is expected Tuesday, but hot and dry weather conditions will continue.