Your friends in the Midwest might laugh, but it's actually cold in Los Angeles. Sure, it's not Minneapolis, keep-every-inch-of-skin-covered cold, but morning temperatures in some parts of the county are near and even below freezing.

That can happen after a Pacific storm moves through. Rich Thompson, a meteorologist with the National Weather Service in Oxnard, says that while cloud cover associated with rain can provide insulation for the air around us, it also can prevent the sun from warming up the surface below. Then, cold air from the northwest can slide in behind a front, pushing temperatures into uncomfortable ranges.

"Clouds act as a blanket, but clouds also prevent the ground from warming up," Thompson says. "It's a double whammy."

Low temperatures this morning were in the low 40s in the L.A. basin, he said. They reached the mid to upper 30s in the San Fernando Valley, and the upper 30s in the San Gabriel Valley. The coldest part of the county appears to be the Antelope Valley, which was solidly showing readings in the 30s, Thompson says. "It's a very chilly morning," he says.

The Los Angeles County Department of Public Health has issued a cold weather alert, expected to stay in effect through Friday, for the Antelope Valley, local mountains, Santa Clarita and the Pomona area. "Wind chill temperatures are expected to be below 32 degrees," according to a county statement.

The health department's interim chief, Jeffrey Gunzenhauser, urges those in poor health or who are susceptible to the cold, including the elderly, to stay indoors. Homeless folks can find a place to stay and transportation to get there through this county website.

Thompson says the high downtown today was expected to reach 57, and the low overnight could reach 40. The cold snap could last through Thursday, but warmer temps are ahead. A high-pressure system is moving over the Southwest, and it will push winds toward the ocean.

"By Saturday we're looking at 69," Thompson says of the highs. "Sunday and Monday could be in the lower 70s."

 That's more like it.