Phoenix, Arizona – An unusually strong ridge of high pressure building over the western United States is setting the stage for an early-season heat wave that could push temperatures to record levels across the Desert Southwest and southern California as the week progresses.
According to the National Weather Service, a gradually strengthening upper-level ridge will trap warm air across the Southwest and Great Basin, allowing daytime temperatures to climb well above typical mid-March levels. Cities including Phoenix, Las Vegas, and Palm Springs could challenge or tie daily record highs over the next several days.
Forecasters say the early burst of heat will expand across California’s interior valleys and much of Nevada through midweek. These elevated temperatures may serve as a starting point for even more widespread record-breaking heat later in the week as the ridge strengthens.
While the Southwest heats up, a much cooler pattern will linger across the Pacific Northwest. High temperatures in Washington and Oregon are expected to remain mostly in the 40s as colder air holds behind a nearby frontal boundary.
Moisture from a Pacific system will also begin increasing rain chances across the Northwest late Sunday into Monday. The most consistent rainfall is expected across northwestern Washington through Tuesday morning.
Residents across the Southwest are urged to stay hydrated and limit prolonged outdoor activity during the hottest part of the afternoon as temperatures continue to climb this week. Meanwhile, unsettled weather will persist across the Pacific Northwest with additional rain possible early this week.
