Pasadena in For Day of Heavy Rain Monday, Could See Small Hail

After several days of above-normal temperatures last week, the Southland will get a dose of badly needed rain on Monday, with a storm possibly arriving as early as late Sunday evening.

A Pacific storm system will move closer to the region Sunday night with widespread rain, high elevation snow and gusty winds through Tuesday morning, according to the National Weather Service.

There will be a chance of thunderstorms that could bring heavy downpours and small hail Monday afternoon through Monday night before drier conditions prevail late Tuesday through Friday, the NWS said.

Clouds were expected to develop slowly over the weekend, but a system will arrive by late Sunday that looks to be “our most significant storm of the month,” forecasters said.

The rain is not expected to start falling until Sunday night. But it will be noticeably cooler, with temperatures dropping between 10 and 15 degrees.

Moderate rates of rain are anticipated Monday morning, with steadier showers anticipated by Monday afternoon. Forecasters said between a half-inch and 1.5 inches of rain are possible throughout the San Gabriel Valley.

Highs were expected to drop to around 70 on Sunday and 62 by Monday.

Stormy conditions are expected to clear out by late Tuesday, with temperatures again climbing by 5 to 10 degrees, according to the NWS.

Here is the detailed forecast:

Overnight: Patchy drizzle and fog. Mostly cloudy, with a low around 53. Southeast wind around 5 mph.

Sunday: Patchy drizzle and fog before 11 a.m. Partly sunny, with a high near 70. South southeast wind 5 to 10 mph.

Sunday Night: A 50 percent chance of rain after 11 p.m. Mostly cloudy, with a low around 51. South southeast wind around 10 mph, with gusts as high as 15 mph.

Monday: Rain before 11 a.m., then showers after 11 am. High near 58. Breezy, with a south wind 15 to 20 mph, with gusts as high as 30 mph. The chance of precipitation is 100%.

Monday Night: Showers and possibly a thunderstorm. Low around 46. South southwest wind 5 to 15 mph, with gusts as high as 25 mph. The chance of precipitation is 100%.

Tuesday: A 20 percent chance of showers before 11 a.m. Mostly sunny, with a high near 68.

Tuesday Night: Partly cloudy, with a low around 49.

Wednesday: Mostly sunny, with a high near 70.

Wednesday Night: Patchy fog after 11 p.m. Otherwise, mostly cloudy, with a low around 52.

Thursday: A slight chance of rain after 11 a.m. Patchy fog before 11 a.m. Otherwise, partly sunny, with a high near 69.

Thursday Night: Patchy fog. Otherwise, mostly cloudy, with a low around 51.

Friday: Patchy fog. Otherwise, partly sunny, with a high near 73.

Friday Night: Partly cloudy, with a low around 52.

Saturday: Mostly sunny, with a high near 74.