Arctic Blast Brings Christmas Chill

A blast of arctic air will keep temperatures well below average in the San Fernando Valley much of the week making things feel, well, a lot like Christmas, forecasters said

Today’s weather will be mostly sunny and cold, with highs reaching the low to upper 50s, said Jeff House, a meteorologist with WeatherData Inc, which provides forecasting services for The Times. At nightfall, the mercury is expected to dive into the mid-to-low 30s around the Valley, with patchy frost expected.

As the week progresses, daytime temperatures will climb slightly each day, reaching into the 60s by Christmas Day. But overnight, predictions are for continued lows ranging from the mid-30s to low 40s.

House attributes the cold snap to a southerly flow in the jet stream, which is taking cold air from Northern Canada and sending it down the Pacific Coast.

“This is how Los Angeles gets its coldest weather, and it will keep temperatures lower than normal all week,” House said. “This is the closest thing you are going to feel to Christmas.”