A cooling trend will continue in Pasadena through the end of the week before a storm system brings the area’s highest chance of rain this weekend, according to the National Weather Service.
Forecasters expect temperatures to fall from a high near 74 degrees Thursday to about 68 degrees Saturday as increasing moisture and cloud cover spread across Southern California. Rain chances will increase Saturday afternoon, with the most widespread precipitation expected Saturday night and Sunday morning.
Thursday’s forecast calls for mostly cloudy skies and a high near 74 degrees. Light south-southwest winds around 5 mph are expected during the afternoon.
Cloudy conditions will continue overnight, with a 20% chance of rain developing after 11:00 p.m. Temperatures are expected to drop to around 56 degrees.
Friday is forecast to remain mostly cloudy, with gradual afternoon clearing and a high near 71 degrees. Winds will remain light.
The weekend storm system is expected to arrive Saturday, bringing a 40% chance of rain after 11:00 a.m. Saturday. Daytime temperatures are forecast to reach about 68 degrees.
Rain is expected to become more widespread Saturday night, when the chance of precipitation increases to 80%. National Weather Service forecasters said rainfall is likely to peak Saturday evening and continue overnight into Sunday morning.
Sunday will bring a 60% chance of rain, primarily before 11:00 a.m. Skies are expected to gradually clear during the afternoon, with temperatures reaching about 70 degrees.
The National Weather Service said most areas could receive between one-quarter and one-half inch of rain from the system, although forecast confidence on exact rainfall totals remains limited. Forecasters noted there is still considerable variation among weather models regarding storm timing and precipitation amounts.
The cooler weather will leave Pasadena temperatures about 5 to 10 degrees below normal for late October through Saturday.
Dry conditions are expected to return early next week. Monday is forecast to be sunny with a high near 74 degrees, followed by mostly sunny skies Tuesday and a high near 76 degrees. Wednesday is expected to remain mostly sunny with temperatures near 74 degrees.
Forecasters said weak offshore flow and building high pressure will support the warming trend early next week, though temperatures are expected to remain slightly below seasonal averages.
Here is the Pasadena forecast from the National Weather Service as of 2:52 a.m. Thursday:
Today: Mostly cloudy, with a high near 74. Calm wind becoming south southwest around 5 mph in the afternoon.
Tonight: A 20 percent chance of rain after 11:00 p.m. Cloudy, with a low around 56. South wind around 5 mph.
Friday: Cloudy, then gradually becoming mostly sunny, with a high near 71. Calm wind becoming south southwest around 5 mph in the afternoon.
Friday Night: Mostly cloudy, with a low around 54. South southwest wind around 5 mph becoming east southeast after midnight.
Saturday: A 40 percent chance of rain after 11:00 a.m. Mostly cloudy, with a high near 68. Calm wind. New precipitation amounts of less than a tenth of an inch possible.
Saturday Night: Rain. Low around 56. Chance of precipitation is 80%.
Sunday: Rain likely, mainly before 11:00 a.m. Partly sunny, with a high near 70. Chance of precipitation is 60%.
Sunday Night: Mostly clear, with a low around 53.
Monday: Sunny, with a high near 74.
Monday Night: Mostly clear, with a low around 55.
Tuesday: Mostly sunny, with a high near 76.
Tuesday Night: Mostly clear, with a low around 56.
Wednesday: Sunny, with a high near 74.
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