Grab That Umbrella: ‘Atmospheric River’ Bears Down on Pasadena

Following a dry but cool day, a wet and potentially da.m.aging storm is expected to arrive in the Southland Wednesday, bringing what forecasters are calling an “atmospheric river” of moisture that will persist into Friday.

According to the NWS, the low-pressure system is already gathering strength off the Oregon coast, and will likely remain mostly stationary through Thursday.

“This will create a steady and nearly persistent strea.m. of moist southwest flow, known as an atmospheric river, … with two to three days of nearly constant rain,” according to the weather service.

“All areas will see moderate to heavy rain later Thursday into Friday as the system swings through California. Things should taper off by Friday afternoon or night.”

Forecasters said Los Angeles County could see 1.5 to 3.5 inches of rain, with 2 to 5 inches possible in the foothills and mountains.

Here’s how Pasadena is expected to fare:

Wednesday: A 30 percent chance of rain, mainly after 11 a.m. Cloudy, with a high near 54. Southeast wind 5 to 10 mph.

Wednesday Night: A 30 percent chance of rain, mainly after 5 a.m. Mostly cloudy, with a low around 44. Southeast wind around 10 mph.

Thursday: Rain likely, mainly after 11 a.m. Cloudy, with a high near 59. Southeast wind 5 to 10 mph, with gusts as high as 15 mph. The chance of precipitation is 60%.

Thursday Night: Rain, with thunderstorms also possible after 11 pm. Low around 44. Southeast wind around 10 mph, with gusts as high as 15 mph. The chance of precipitation is 100%.

Friday: Rain and possibly a thunderstorm before 11 a.m., then showers likely and possibly a thunderstorm after 11 a.m. High near 54. The chance of precipitation is 90%.

Friday Night: Partly cloudy, with a low around 41.

Saturday: Sunny, with a high near 60.

Saturday Night: Mostly clear, with a low around 42.

Sunday: Mostly sunny, with a high near 66.

Sunday Night: Mostly cloudy, with a low around 47.

Monday: Mostly cloudy, with a high near 67.

Monday Night: Partly cloudy, with a low around 46.

Tuesday: A slight chance of rain. Mostly sunny, with a high near 63.