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Western US weather

Cooler into California and the Southwest into early next week thanks to a slow upper low

By Brian Thompson , AccuWeather meteorologist
5/02/2019, 10:17:28 AM

Cooler weather and spotty showers will move into California while the Pacific Northwest has sunny, warm days ahead.

An upper-level low moving into California this weekend will not bring much rain, but it will cool things off a little bit, especially heading into Sunday and Monday.

The marine layer this morning does not appear to be as solid as some recent days. As this upper-level low approaches, it will likely beef up the marine layer some across Southern California Thursday and Friday nights.

As the upper low comes ashore into Sunday, some showers will likely break out across Central California, even across the San Joaquin Valley, where rain is very infrequent during the month of May.

Western Blog Model 5/2

The upper-level low moving inland late Sunday. This will produce some unsettled and cooler weather into next week.

These upper lows are simply cold pockets of air aloft, which will translate to some cooler days down at the surface by Sunday and Monday. Temperatures both days may struggle to get out of the mid-60s in Los Angeles and San Diego.

Also early next week, temperatures will get knocked down significantly in Las Vegas, where highs will be in the 70s. Phoenix will also see a noticeable drop, going from the mid-90s to the lower 80s next week.

Especially on Monday, there will be more clouds and perhaps even a shower or two throughout Southern California. Rainfall amounts, though, shouldn’t be anything to write home about in most cases. Even so, a shower or two can be enough to equal the monthly average in some areas. San Diego, for instance, averages 0.12 of an inch of rain for the month of May.

At the same time, it will be a partly to mostly sunny weekend in the Pacific Northwest. Temperatures in Seattle will get well into the 60s to near 70 over the weekend, while Portland gets into the 70s both days.

General trouginess will persist into next week across the West, a few more disturbances could trigger additional showers across the higher terrain of the Sierra and across Nevada into the middle of next week.

Eventually, a ridge will gradually build in heading toward next weekend, which should lead to a quieter pattern overall.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or


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Western US weather