Lightning. Erratic Winds. Hail. Waterspouts. Flooding. Forecasters suggest these environmental conditions are all possible through Tuesday in the Bay Area, and the Sierra Nevada will likely get its first significant snow of the season. Gass said the storm could bring a suite of environmental issues with it, including lightning, offshore water spouts and small hail. But he said the "biggest threat will be nuisance flooding" where areas that typically pool water could flood.
The heaviest rain is expected from the middle of the afternoon and into the evening commute. At about 1 p.m., cities like Oakland, San Mateo and Half Moon Bay will see lighter rain. The East Bay will see heavier rain by 3 p.m. and by 4 p.m., in the middle of the commute and it won't exit until around 7 p.m. or 8 p.m.