First of 2 Storms Batters Southland; Largest Storm of the Season Expected Sunday

Rain battered the Southland as the first — and smaller — of two anticipated storms doused the region and flooded multiple streets during the morning rush hour, making the commute a nightmare for thousands of Angelenos. The next storm is expected to arrive Sunday.

By early afternoon Thursday, however, the brunt of the storm had moved out of the area. Forecasters warned that showers and isolated thunderstorms were still possible early Friday.

“The main frontal band has passed to the east, however, it has left behind a moderately unstable air mass which will be able to produce scattered showers and possibly even an isolated thunderstorm or two with brief periods of heavy rain,” according to a mid-afternoon statement by the National Weather Service Thursday.

Thursday’s deluge, however, was only a preview of what’s to come beginning as early as Sunday, when the area will be hit by what forecasters are calling “the largest storm of the season.”

The storm is “forecast to spin down the coast and lift an atmospheric river into and across Southern California,” according to the NWS.

“While the exact timing, rates and amounts are still uncertain, it is very likely that this will be a serious two- to three-day storm system,” forecasters said.

“Over the (Sunday to Tuesday) period the early estimates call for widespread rain amounts of 2 to 4 inches for lower elevations and likely twice those amounts in the south facing mountains,” according to the NWS. “There are more than a few (forecasts) that call for much higher amounts than those. Citizens and authorities need to be aware of the likelihood of significant hydrologic issues.”

The downpours Thursday left their mark across the region. Heavy rain began falling well before daybreak Thursday, making for a soggy morning commute. Flooding was reported on freeways and streets across the region.

Slippery conditions caused cars to spin out on freeways in Los Angeles and Orange counties, resulting in various lane and road closures. The California Highway Patrol reported at least 50 spinouts and crashes on freeways and roads in the central Los Angeles area Thursday morning.

Despite the dramatic impacts of the overnight and early morning rain, forecasters said the region actually got a bit of a break thanks to the speed at which the storm system moved through the area.

“The front is moving along at a decent clip and this will minimize the flash flooding threat — still advisory level flooding is almost certain in and around the front,” forecasters wrote in a statement early Thursday morning.

As of 1:30 p.m. Thursday, 1.4 inches had fallen in Pasadena.

Here is the most recent National Weather Service forecast for Pasadena, reported at 3:18 a.m. Friday morning:

Today: Isolated showers before 10 a.m. Mostly sunny, with a high near 60. West southwest wind 5 to 10 mph, with gusts as high as 15 mph. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 41. South southwest wind 5 to 10 mph.

Saturday: Mostly sunny, with a high near 59. East wind 5 to 10 mph becoming south in the afternoon.

Saturday Night: Rain likely, mainly after 4 a.m. Mostly cloudy, with a low around 44. East southeast wind around 10 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.

Sunday: Rain. High near 59. Windy, with a southeast wind 15 to 20 mph increasing to 25 to 30 mph in the afternoon. Winds could gust as high as 40 mph. Chance of precipitation is 80%. New precipitation amounts between 1 and 2 inches possible.

Sunday Night: Rain. The rain could be heavy at times. Low around 50. Breezy. Chance of precipitation is 90%.

Monday: Rain and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 59. Breezy. Chance of precipitation is 80%.

Monday Night: Rain and possibly a thunderstorm. Cloudy, with a low around 48.

Tuesday: Rain. Cloudy, with a high near 58.

Tuesday Night: Rain likely, mainly before 4am. Mostly cloudy, with a low around 43.

Wednesday: Rain likely. Mostly cloudy, with a high near 57.

Wednesday Night: A chance of rain. Mostly cloudy, with a low around 41.

Thursday: A chance of rain. Partly sunny, with a high near 56.