Biggest storm in weeks forecast to dump hail in SF Bay Area Amy Graff As a late winter storm moves across the San Francisco Bay Area, there's a chance for sporadic lightning, brief heavy downpours, low elevation snow and especially small hail in the Tuesday and Wednesday weather forecast, according to the National Weather Service. This could be the last significant storm before the end of winter, and it's the biggest system the region has seen in weeks — though rainfall will generally be moderate. San Francisco recorded 0.43 inch of rain Feb. 12, and the last time a storm delivered more than a half-inch to the city was Feb. 7, said Brayden Murdock, a forecaster with the weather service.