Southern California and Desert Southwest Brace for Major Holiday Weather Shift with Storms Returning Next Week

After nearly a month of unusually warm and dry weather in the Desert Southwest and Southern California, a huge pattern shift is forming, and it is projected to come just in time for the Christmas holiday season. Forecasters are increasingly confident that the continuous ridge that has kept the region dry will weaken and shift east, allowing Pacific storms to move farther south.

A Major Pattern Flip Expected Around Christmas Week

Meteorologists are growing convinced that a deeper West Coast trough will form next week, allowing a series of disturbances to sweep into California. Early forecasts indicate that unsettled weather will arrive around Christmas Day, if not sooner, bringing an end to the extended period of dry warmth.

This is the first significant storm threat in weeks, with repercussions expected across Southern California, Central California, and parts of Arizona and Nevada.

Storms May Tap Into Tropical/Subtropical Pacific Moisture

Forecast information shows that the forthcoming pattern may again connect to warmer tropical or subtropical Pacific moisture plumes, perhaps leading to:

Higher snow levels initially above 7,000–8,000 feet
Widespread rainfall statewide
Potentially heavy precipitation in some regions

However, cooler air behind each system may gradually reduce snow levels, increasing the likelihood of accumulating mountain snowfall later in the trend.

Storm Timing: Still Uncertain but Growing More Likely

Although the first storms are still around ten days away, many agencies—including NOAA and CW3E atmospheric river monitoring—show:

Increasing probability of moisture plumes hitting California
Elevated risks for heavy precipitation between December 23–29
Potential for high winds in parts of the West
Heavy snow possible across mountain ranges, including the Sierra Nevada and Southern California mountains

Confidence grows that this will not be a one-time occurrence but rather a succession of storms continuing through Christmas and possibly beyond.

Model Outlook Highlights

According to NOAA’s 8-14 day forecasts:

Above-normal precipitation is favored along nearly the entire California coast
Temperature trends shift cooler as the ridge weakens
Travel across mountain passes may become increasingly difficult

CW3E atmospheric river probability maps reveal many IVT plumes aimed at California between December 21 and 26, increasing the risk of prolonged wet weather.