As thick fog cloaked many sections of Southern California today, the region was warned that rain – real, heavy rain – is possible in a few days.
Light rain was called for Sunday, heavy rain starting Monday night, and possible burst of intense, heavy rain was called possible for Tuesday.
A one-two set of weather systems was rotating in the North Pacific, and the first, weak wave of storms was to carry light rain to the parched area late tonight and early Sunday.
About a tenth of an inch was called likely in the L.A. basin, possibly up to a quarter inch in the foothills and mountains.
But it was the second, Tuesday pulse that was described as the real rainmaker. “A very large and strong upper level low” is how the National Weather Service office put it.
“Strengthening south to southwesterly flow aloft ahead of this storm is expected to tap into a rich subtropical moisture source well off the coast of Mexico, increasing the potential for heavy rainfall,” the NWS predicted.
It was too early to say exactly when that rain would hit, and how much, but the NWS said “the potential exists for 1 to 2 inches of rain in coastal and valley areas.”
And the winds coming out of the south means clouds will hit the local mountains head-on and dump rain on the south-facing foothills, like the recent fire areas near Azusa and Malibu.
“There is a chance of a 2-to-3-hour burst of very heavy rainfall with this storm, which will bring the threat of flash flooding and mud and debris flows in and around recent burn areas,” the NWS warned.
The subtropical nature of this rain means the freezing level will be quite high, above 7,500 feet, and only the highest mountains near Wrightwood will get snow.
Scattered rain might continue into Thursday, the NWS warned.