Major Winter Storm to Drench Pasadena With Potentially Heavy Rain Starting Wednesday

National Weather Service forecasters are alerting Pasadena residents to prepare for a significant winter storm system that will bring substantial rainfall to the area from Wednesday through Friday. The storm is expected to deliver between 1.5 to 3 inches of rain at lower elevations, with potential rainfall rates approaching one inch per hour during its peak intensity.

Tuesday remains cool and partly cloudy across Pasadena, with morning low clouds and temperatures struggling to reach 60 degrees. The deep marine layer has pushed inland, bringing cooler than normal conditions to the Los Angeles basin.

The approaching storm system will make its presence felt early Wednesday as an initial wave of moisture moves into Southern California. Rain is expected to develop by midday Wednesday, bringing light to moderate precipitation to the Pasadena area. A brief lull may occur Wednesday evening before conditions deteriorate significantly early Thursday.

Temperatures will remain notably cool throughout the week, with highs hovering in the mid-50s to lower 60s, several degrees below seasonal normals for February. The persistent cloud cover and rainfall will help maintain these cool conditions across the region.

The most intense period of rain is forecast for Thursday into early Friday morning, when the main storm system arrives. The event will begin with steady rain during the pre-dawn hours Thursday, transitioning to potentially heavy rainfall as the cold front moves through late Thursday night. Rainfall rates could reach dangerous levels, with forecasters predicting up to an inch per hour during the storm’s peak.

While the strongest winds will primarily affect higher elevations, Pasadena residents should prepare for gusty conditions during the passage of the cold front Thursday night. Any thunderstorms that develop could bring locally stronger wind gusts to the area.

The weekend will bring welcome relief as high pressure builds into the region. Saturday will feature partly cloudy skies with temperatures beginning to moderate, though still remaining below normal. By Sunday, residents can expect partly to mostly cloudy conditions with temperatures warming into the mid-60s to lower 70s.

The intensity of the rainfall has prompted the National Weather Service to issue a Flash Flood Watch for the area from Thursday morning through early Friday morning. Pasadena residents, particularly those near the foothills or in flood-prone areas, should stay alert and monitor conditions closely.

Looking ahead to next week, conditions appear to stabilize with a slight chance of morning marine layer clouds. Temperatures are expected to remain near or slightly below seasonal averages.

The coming storm represents the most significant rainfall event for Pasadena so far this winter season, with total precipitation amounts potentially exceeding several inches. Residents are advised to clear storm drains, secure outdoor items, and prepare for possible local street flooding during periods of intense rainfall.

Here is the latest forecast for Pasadena as of 3:33 a.m on Tuesday, February 11, from the National Weather Service:

Tuesday: Cloudy through mid morning, then gradual clearing, with a high near 60. Light and variable wind becoming southwest 5 to 10 mph in the morning. Winds could gust as high as 15 mph.

Tuesday Night: Rain likely after 4:00 a.m. Increasing clouds, with a low around 42. West wind 5 to 10 mph becoming east after midnight. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Rain. High near 55. Calm wind becoming east southeast around 5 mph in the morning. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday Night: Rain. Low around 47. East wind around 5 mph. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

Thursday: Rain. High near 58. Chance of precipitation is 100%.

Thursday Night: Rain. Low around 48. Chance of precipitation is 100%.

Friday: Rain, mainly before 4:00 p.m. Mostly cloudy, with a high near 59.

Friday Night: A chance of rain before 10:00 p.m. Partly cloudy, with a low around 45.

Saturday: Mostly sunny, with a high near 63.

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

Sunday: Partly sunny, with a high near 69.

Sunday Night: Patchy fog. Otherwise, mostly cloudy, with a low around 48.

Washington’s Birthday: Patchy fog. Otherwise, partly sunny, with a high near 69.