Weather Outside Your Window: LA about to experience dramatic changes as storm eyes Southwest

Temperatures will come crashing down, and it may feel like a sudden shift in seasons as some areas across the drought-stricken Southwest will pick up beneficial rain.

By Alyssa Smithmyer, AccuWeather Meteorologist

Published Feb. 28, 2022 10:50 AM EST | Updated Feb. 28, 2022 3:34 PM EST

AccuWeather forecasters say that some drought-stricken areas of the southwestern United States will soon receive beneficial rainfall as the soaking storm that has been unloading excessive rain over the Northwest makes progress farther to the south and east. Even areas that will not experience precipitation will face major changes in the form of a temperature roller-coaster ride.

"After stormy weather pounds the Pacific Northwest early this week, the same moisture driving heavy rainfall over the region will shift south and east by midweek. This southward shift in available moisture will allow wet weather to spread over more of Oregon by Wednesday and push into much of Northern California by Thursday," AccuWeather Meteorologist Mary Gilbert said.

Over the weekend, Owl Mountain, located in the Olympic National Park in Washington, recorded a three-day rainfall total of 4.49 inches, and even more precipitation is on the way. Rain will continue to soak the Washington and Oregon coastlines as it pushes inland through Wednesday. As moisture reaches farther inland, snow will develop over the mountain ranges of the region.

The northward bulge in the jet stream over the West will continue to guide storms into the region through midweek. But, by late in the week, the jet stream is expected to dip southward over the Southwest and allow quite the pattern change.

Southwest cities will go from experiencing dry weather and above-average temperatures early on this week to dealing with unsettled weather and near-normal or even below-normal highs later this week.

Places such as Los Angeles and Phoenix are expected to record daytime highs well into the 80s F by Tuesday, roughly 10-15 degrees Fahrenheit above the norm for the first week of March. The building heat combined with the generally dry weather may briefly remind residents of hot summer days.

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According to the U.S. Drought Monitor, nearly all of the Southwest is experiencing at least moderate to severe drought conditions. Portions of Oregon, northwestern California, central Nevada, Utah and New Mexico are currently experiencing extreme drought, the second-highest level of drought classification designated by the U.S. drought monitor. Central Oregon and central Nevada also have areas that are enduring an exceptional drought, the highest level recognized.

Any rain that spreads to the Southwest later this week will help to make a dent in drought levels as areas farther north across southern Oregon will also pick up beneficial rainfall this week.

"Wednesday night into Friday, places like Medford, Oregon, and Redding, California, can receive some much-needed precipitation. Both cities were bone dry in February, recording just 0.08 of an inch and 0.02 of an inch of rain, respectively, as of Feb. 27. That's just 4 percent of the average monthly rainfall for February in Medford and statistically zero percent of the same parameter in Redding," Gilbert said.

Temperatures will begin to drop across the Southwest as the jet stream ushers in cooler air from the north. Near-freezing temperatures will infiltrate the mountainous regions across California and Nevada on Thursday and Friday.

"Los Angeles will likely struggle to reach even the mid-60s by Friday," said Gilbert. That's a few notches below normal with the average high in L.A. sitting at 69 F on Friday.

As cooler air arrives, rain and snow will begin to move southward.

"By Friday, the bulk of the moisture from the upcoming storm is set to be located over the Rockies while temperatures come slamming down across the Southwest," noted Gilbert.

AccuWeather forecasters say that the storm's impacts will be far from over after it spreads across the West. Widespread impacts are expected from the Plains to the Northeast as the storm shifts eastward and eventually moves into the Central states heading into the weekend.