How much rain does it take to set a record this time of year in Southern California? In some areas, anything more than a trace amount will do.
It’s not that we are getting an extreme amount of rain, but rather the records that stand are so low.
Several records are expected to be broken Thursday, when between .25 and .75 inches are expected along the coast and in the valleys. An inch is expected in the mountains.
“That will give us a pretty decent amount of rain for this time of year,” said NBC4 forecaster Shanna Mendiola.
The record for May 16 in downtown Los Angeles was set in 1996 — a meager .04 inches. At LAX, the record of .05 also was set in 1996. Long Beach and Lancaster only reported a trace in 2011, enough for records.
The monthly average for May is a quarter-inch.
The wettest day recorded in May was May 8, 1977, when we got about 2 inches. What about the second half of May? The wettest late May day was back in 1990 on the 28th when we got over an inch of rain.
It’s not the amount of rain, but the timing that might cause problems. Widespread rainfall early Thursday during the morning drive.
“Plan ahead for that,” said NBC4 forecaster Belen De Leon. “The heaviest rain will be falling in the morning hours.”
One of the toughest morning commutes was on the westbound 91 Freeway in the Corona area, where a big rig fire forced lane closures until about 6 a.m.
Wet conditions will continue through Thursday morning, and there’s a slight chance of thunderstorms and brief downpours.
Rain will fall for four to eight hours, averaging up to .20 inches per hour. That could mean street flooding and ponding water.
The system was making its way onshore Wednesday in Oregon and Northern California. It will dip south late Wednesday, but SoCal’s roads should still be dry by the evening drive.
The average rainfall for the whole month of May is .26″ and based on Thursday’s rain forecast we are looking at receiving up to three times the monthly average rainfall amount in one day. Unfortunately, it will mostly fall in the morning hours as you’re trying to get to work.
Rain will taper off Thursday after and evening before sunny conditions on Friday.
The snow level in the San Gabriel Mountains will drop to 6,000 feet. Winter driving conditions.
Rain also is in the forecast for Sunday and Tuesday.