Enjoy the dry, cool days that mark the start of this week in the Sacramento area. Then get ready for an "atmospheric river" late in the week that will bring perhaps 3 inches of rain to the valley region, the National Weather Service said today.
Darren Van Cleave, NWS meteorologist, said the current fair days and cool nights with patchy morning fog are forecast to deliver daytime highs in the mid-60s and overnight lows in the low 40s.
The change comes Wednesday afternoon with what will amount to a "warmup" storm that should deliver 0.5 of an inch to about 1 inch to much of Northern California.
That system, Van Cleave said, should be brief, giving way on Thursday to a brief short drying on Thursday.
By late Thursday, that "atmospheric river" will be headed straight for the capital area and will bring strong southerly winds, he said.
The term of art - atmospheric river - tells the story: Van Cleave describes it as a "garden hose ... focused right in our area."
Forecast models show the Sacramento region "getting very wet with this into the weekend - in the neighborhood of 3 inches (of rain) or more for the valley."
Atmospheric rivers, he said, tend to be longer than they are wide. This one fits that description. But they also tend to affect an area for about 12 to 24 hours. Forecasts show that this one lingering over the valley beyond Thursday night well into the weekend.
"I don't see a significant change until Sunday," Van Cleave said.
That river of moisture will transport fairly warm air - meaning that the foothills and western slope of the Sierra Nevada are likely to see mainly rain, too.