PACIFIC STORM COULD DROP 2.5 INCHES OF RAIN
Cold system moving in Thursday morning may bring potentially damaging winds and more urban flooding
A cold Pacific storm will drop 2 to 2.5 inches of rain across much of San Diego County from Thursday morning to Friday afternoon, possibly causing heavy runoff in a region still recovering from last week’s damaging, storm-induced flooding, the National Weather Service said.
The heaviest rain will fall on Thursday afternoon and evening and could include thunderstorms capable of dropping 0.75 inches of precipitation per hour, a rate that typically leads to urban flooding. Isolated spots could receive as much as 3 inches of precipitation. In San Diego, city crews were working to clear storm channels in preparation.
Forecasters stressed that the fast-moving system will make a mess of Thursday’s evening commute on local freeways and could leave people seeking shelter as they await trolley service, including in southeastern San Diego, where rain and flooding were most intense last week.
The new storm also will cause parts of the San Diego River to rise to at least 10 feet, leading to flash flooding in some areas, notably in Mission Valley, where many unhoused people live in the riverbed.
The rain will be preceded by winds out of the south that will gust 35 to 45 mph in spots like Imperial Beach, possibly damaging trees and signs.
The weather service also said that the county will get hit by a second major storm that will begin to push ashore late Sunday night and will cause big downpours on Monday and Tuesday, again raising the risks of urban flooding. That system will move slowly, allowing it to absorb additional moisture from the subtropics as it approaches land. Some
areas could get 1.5 to 2 inches of precipitation from that storm.
Computer models suggest that Thursday’s storm will not produce the sort of unusually long and intense rainfall that fell last Monday and overwhelmed creeks and outdated stormwater runoff systems in parts of San Diego. That earlier system dropped rain at 1.25 to 2 inches per hour, making it a meteorological anomaly in Southern California.
But the storm that will dive into San Diego from the Pacific will tap into subtropical moisture, which can lead to comparatively short but potentially damaging downpours.
The weather won’t feel subtropical. San Diego’s daytime high will be 63 on Thursday and 59 on Friday and Saturday. The seasonal high is 67.
The storm also will generate ocean waves in the 8to-10-foot range, eroding beaches that have already been torn up by lots of big surf over the past month. Forecasters are advising the public to stay away from coastal cliffs, jetties and piers.
The rain could make it harder to repair the portion of railroad track in San Clemente that was damaged by last week’s storm. Workers are still trying to restore passenger rail service between Orange County and San Diego.
Several inches of snow could fall at elevations as low as 4,000 feet on Friday as the cold front moves through. Mount Laguna and Palomar Mountain have received comparatively little snow so far this winter.
The county and local cities will provide the public with free sandbags at many locations. Go to sandiegocounty.gov for a complete list. The county’s emergency app, which is called SD Emergency, is available for
iPhone users in the App Store and for Android phone users in the Google Play store.
Seasonal rainfall update
Since the rainy season began on Oct. 1, San Diego International Airport has recorded 5.06 inches of precipitation, which is 0.29 inches above average. Oceanside Airport has recorded 5.62 inches, which is 0.05 inches above average. Ramona has received 4.87 inches, which is 1.79 inches below average.