The first significant rain and snow of the season is expected to develop in Southern California and the Southwest midweek and will bring some relief from abnormally dry conditions.
A change in the upper-level weather pattern will allow rain and mountain snow to develop in the West.
Early next week, a cutoff upper-level low will be located near the Baja Peninsula, which could pull in some tropical moisture from Tropical Storm Raymond. Raymond might reach the southern tip of the Baja California Peninsula by late Sunday, but will be weakening.
The cutoff low will combine with a low-pressure system that'll move into the Southwest midweek. This system will first push into the Northwest early in the week before diving southward.
Rain and higher elevation snow will develop as a result of this setup.
Wet Forecast
The Northwest will see rain and mountain snow Monday and Tuesday before the system tracks into the Southwest.
Rain chances will increase in Southern California and much of the Southwest by Tuesday night. Snow will fall in the higher elevations of the Sierra and Rockies.
There is some uncertainty in the forecast as to how far north the rain and snow will reach in California, and as a result, the best chance for precipitation is in Southern California.
The chance for rain and higher elevation snow will continue through Thursday for most locations. This system will likely begin to move away from the Southwest by Friday.
Cooler temperatures are also expected to accompany the increase in cloud cover and precipitation. High temperatures will be 10 to 20 degrees above average for much of the West Monday and Tuesday, but temperatures will return closer to average Wednesday and Thursday across the region, with highs as much as 10 degrees below average in the Southwest.
Los Angeles and Phoenix's high temperatures will drop from the 80s on Monday to the 60s on Wednesday.
How Much Rain and Snow?
Light to moderate rainfall is anticipated from Southern California into the Four Corners region. More than an inch of rain will likely fall in some spots, especially in Arizona, through Thursday.
Several inches of snow will likely pile up in the Sierra, with more than a foot possible in the higher elevations of southern Utah, southern Colorado and Arizona.
Precipitation will be spread out over several days, so widespread flash flooding is less likely, but could occur in some heavier downpours.
It is too early for rain and snow total specifics, given the pieces to this system won't come together until early next week, so be sure to check back frequently for updates.
This will likely be the first notable precipitation in this region so far this wet season, which typically begins in November and lasts through April.
More than 80% of California is at least abnormally dry, according to the latest U.S. Drought Monitor, since precipitation has not fallen this wet season. This is a big jump from Nov. 5, when less than 18% of the Golden State experienced abnormally dry conditions.
Los Angeles and San Diego average around an inch of rainfall from Oct. 1 through Nov. 15, but have not seen any rain so far during this period. It has been the eighth driest start to the water year in downtown San Francisco, where only 0.03 inches has been measured and it does not appear that much, if any, rain will fall here with this upcoming system.
Drought conditions have also developed and expanded in the Four Corners region since late-summer due to a relatively dry monsoon season in Arizona and New Mexico, according to the U.S. Drought Monitor.
Drought conditions cover about a quarter of the West.
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.
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