Weather Tracker: San Francisco Hit by Second Rainiest Day on Record | California

California ended 2022 with heavy rains that caused flooding in and around San Francisco, leading to landslides, flooded roads and evacuation orders. The second-highest daily rainfall total on record fell on New Year’s Eve in downtown San Francisco (with records dating back to 1949), with 5.46 inches recorded. That’s more than 25 percent of average annual precipitation, and just 0.08 inches less than the all-time high set in November 1994.

The recent heavy rains were part of an atmospheric riverine event – ​​where a conveyor belt of warm, moist tropical air is able to interact with and feed mid-latitude storm systems, greatly enhancing precipitation potential.

Due to an unusually dry start to 2022, San Francisco had seen about 20% of normal total precipitation through early October. Prior to this latest event, total precipitation since October was near average, meaning that – despite December’s wet end – San Francisco ended 2022 with only about two-thirds of the annual average precipitation.

After a brief lull in the heavy rains that began this week, a new atmospheric river is expected to hit California starting Wednesday, bringing more heavy rain, high winds and mountain snow. About 3 inches of rain is currently forecast with the next storm system for lowland areas around San Francisco Bay, with totals exceeding 6 inches in the Coast Mountains to the north and south.