By Jim Purpura. Posted December 9, 2011, 2:19 PM.

It looks like southern California weather is about to see a pattern shift for the next one to two weeks...from a cool, dry pattern to a stormy, cool, wet one.

The winds aloft are beginning to shift to more northwesterly, and this will set the stage for at least two wintry storm systems.

This first will move into the area late Sunday, and stay around through Tuesday before moving off to the east. This storm looks to bring waves of showers and thunderstorms to Simi Valley through Tuesday. Right now, it looks like the heaviest rainfall...and snow in the mountains...will be on Monday.

Expect rainfall totals from this storm to be a 1/2 to 1 inch across the Simi Valley area and 1 to 2 inches in the mountains below 3500 feet and snow above that level.

There will be a brief break in the weather on Wednesday, then a second storm system affects portions of southern California beginning Wednesday evening through Friday. Most computer forecasts are now indicating these storms will miss the Simi Valley area and head toward San Diego, but some light rain amounts could still fall across the area.

Be sure to check back with WeatherCurrents for updates on this developing winter weather system.