Bay Area Storm Brings Heavy Rain Snow

A late-season Pacific storm moved into the Bay Area on Monday and will keep rain, thunderstorms and mountain snow in the forecast through Wednesday. (weather.gov) The National Weather Service said the main band of rain was expected to sweep through Monday into Tuesday morning, with post-frontal showers lingering into Wednesday. Thunderstorm chances were forecast to peak Tuesday afternoon and evening at 20% to 30%. (forecast.weather.gov, weather.gov) Forecasters said the main hazards were lightning, locally heavy rain and small hail, with localized flooding possible under heavier cells. The weather office also posted wind and marine advisories across parts of the region on Tuesday morning. (weather.gov, weather.gov) This is unusual for late April because the Bay Area’s main rainy season usually fades by the start of the month, not deepens into a three-day storm. The Mercury News reported this month is on track to be the region’s wettest April in nearly a decade. (mercurynews.com, forecast.weather.gov) The system is cold enough to bring snow to higher elevations while rain falls at lower levels, which is why the Sierra picked up winter storm alerts at the same time San Francisco faced a wet commute. The Bay Area forecast office said heavy high-elevation snow would continue in the Sierra through Wednesday. (weather.gov, ktvu.com) The timing also matters for travel and outdoor plans because the heaviest rain was expected around the Monday evening and Tuesday morning commute windows. The forecast discussion warned of a “messy evening commute” as rain spread across the San Francisco Bay Area. (forecast.weather.gov) This storm follows an earlier April swing from heat to rain across Northern California. Patch reported that a separate storm earlier this month came after a heat wave that cut Sierra snowpack by roughly 25%. (patch.com) The forecast turns quieter later this week, with the National Weather Service calling for seasonal temperatures and drier conditions after Wednesday. For now, the Bay Area is spending the first half of this week under a spring storm that looks and behaves more like winter. (forecast.weather.gov)