Bay Area sees first signs of rain as major pattern change is forecast

Forecasters say light, 'nuisance' rain may begin Sunday evening in the Bay Area after a month without notable precipitation, and the National Weather Service predicts a shift toward a wetter pattern by mid-February.

Light, mostly nuisance rain is expected to begin Sunday evening across parts of the Bay Area after a monthlong gap without notable precipitation. The change follows recent record-high temperatures and a prolonged high-pressure ridge over the region. The National Weather Service's Climate Prediction Center reports a developing trough over the West that favors a wetter pattern from the West Coast to the Continental Divide by mid-February. Forecasts also show daytime temperatures dropping toward seasonal averages near 60 degrees by early next week. Key details: - Light rain is forecast to start Sunday evening into Monday, with the North Bay having the highest likelihood of showers. - The South Bay has a less than 15% chance of light rain Sunday evening, according to the weather service. - Forecasters expect higher chances of rain early next week, with Monday through Wednesday totals around a quarter inch in many locations. - The North Bay and coastal mountains may receive slightly higher amounts than other areas. - The pattern change is linked to a low-pressure system moving south along the California coast that will break down the existing high-pressure ridge. - Temperatures are expected to fall back toward seasonal averages by early next week. Summary: This light rain is the initial signal of a move back to a somewhat active weather pattern for the region. Forecasters expect higher chances of rain early next week with modest totals through Wednesday and a taper by Thursday, followed by the possibility of renewed activity. Forecasts and outlooks are subject to change as the system evolves.