A winter storm “with enough oomph to trigger thunderstorms” made its way ashore in Southern California Sunday, bringing rain and storm to the drought-stricken region.

Heavy rain began to move ashore at midday in a band from northern Orange County to LAX, and the National Weather Service reported its radar detected rain falling at a rate greater than a half inch per hour.

The rain was measured at Long Beach, the Palos Verdes Peninsula, the South Bay cities and inland towards downtown Los Angeles and the Pasadena area.

An urban and small-stream flood advisory was issued for the central part of Los Angeles County.

And a national television audience was treated to a rare sight — November rain in Southern California — as the Rams-Dolphins NFL game was played in a steady rain at the L.A. Memorial Coliseum.

Snow levels were expected to drop to the 7,000- or 6,000-foot elevation contours Sunday and tonight, enough to dust the mountains with 3-8 inches of snow at mountaintops higher than Mt. Wilson.

But that snow would turn to rain below 6,000 feet, and would not ice up the Grapevine or Cajon Pass, forecasters at the National Weather Service said.

A winter weather advisory said up to 12 inches of snow would fall at the highest elevations of the San Gabriel and San Bernardino mountains. Cold winds gusting to 40 miles per hour were predicted for tonight in the mountains.

But the convective behavior — energy that is lifting moisture into the atmosphere — might trigger thundersnow, and those types of clouds can drop larger volumes of snow, the NWS warned.

Thuderstorms were also possible across the Southland’s flatlands and coastline, the NWS cautioned.

A flash flood watch was up for recent burn area in Los Angeles and Ventura counties, with heavy rain expected between 4 p.m. Sunday and 4 p.m. Monday. Rain could fall at the rate of one inch per hour under the thunderstorms that might blossom.

Recent fire areas near Santa Clarita were singled out for particular dangers of debris flows. Pacific Coast Highway west of Malibu, in the Station Fire burn area, have seen rockfalls in recent similar storms, CHP officers have said.

By midday, small amounts of rain had fallen in the San Fernando Valley and the Los Angeles coastal plain. But hard rain had hit some other areas, like 1.3 inches near Boney Mountain and .85 inches at Leo Carrillo Beach, both west of Malibu, and .27 inches at upper Las Flores Canyon.

Other unofficial NWS midday totals included .22 inches at Santa Fe Dam in El Monte, .46 inches at Del Valle near Castaic, and .22 inches at the Chilao Ranger Station, near Mt. Wilson.

–City News Service

Updated at 3:51 p.m. Nov. 20, 2016

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