A fast-moving storm will move ashore on Halloween night and intensify before dawn Sunday, dropping up to 0.8 inches of rain in some of San Diego County’s coastal cities and an inch or more across inland valleys and foothills, the National Weather Service says.
The system — known as a pineapple express because it forms in the tropical Pacific — will begin producing significant rain early Saturday night, during the height of trick-or-treating. It will grow stronger around 1 a.m. Sunday and mostly fade away by mid-morning. Saturday evening temperatures will be in the low to mid-60s.
Forecasters say the coastal rain will be heaviest from San Diego south to the border. Winds will be comparatively light, but there is an outside chance of thunderstorms, which can produce strong, isolated gusts.
The storm could push San Diego’s total October rainfall above 2 inches. The city averages about a half-inch in October.