BARSTOW — Cooler weather this week also could bring slight rainfall, with its best chance likely coming Wednesday morning, according to the National Weather Service.

Colder systems Wednesday morning and afternoon could mean "as much as half-an-inch" of rainfall in the region, said meteorologist Stephanie Sullivan.

"There's a low-pressure system that's moving into Southern California and tapping some sub-tropical moisture," Sullivan said.

An active pattern will be in effect for the next couple of weeks, with "another storm coming on Saturday, possibly into Sunday," she said. Any rainfall then, however, is expected to be less than on Wednesday.

Here's the forecast for the week:

Tuesday: A 25 percent chance of rain, mainly after nightfall. Partly cloudy, with a high of 73. Winds could gust as high as 21 mph. 

Wednesday: Cooler with periods of rain and a high of 63 degrees. Nighttime lows will be near 46, with winds gusting to 21 mph again.

Thursday: Gusty winds will linger and there will be periods of sun and clouds. The high will be 67, the low 42. Winds could gust to 23 mph.

Friday: Sunny and mild, with a high of 74, winds topping out at 14 mph, and an overnight low of 50.

Saturday: Cooler with a few showers, and winds gusting to 29 mph. The high will be 64, the low 45.

Sunday: Partly sunny, with a high of 67 and a low of 46. Winds will gust to 17 mph during the day, but increase to 34 mph at night.

Shea Johnson can be reached at 760-955-5368 or Follow him on Twitter at @DP_Shea.