While parts of the country are still feeling the brunt of winter, Southern California is headed into an overheated weekend that could bring record-breaking temperatures.
Unfortunately for thousands of runners, the heat coincides with Sunday's annual LA Marathon, whose start time has been moved up by a half-hour to 6:55 a.m. Runners also will have access to ice, cold towels, misting stations and even "cooling buses."
An enormous high-pressure ridge centered 800 miles offshore is moving toward the region, the National Weather Service said Thursday.
The dome-like ridge will be right over Southern California on Saturday and Sunday, with highs of 90 or above in Los Angeles and surrounding cities — some 20 degrees above normal for the period, said Stuart Seto with the weather service in Oxnard.
The 90-degree high for downtown Los Angeles on Saturday is expected to beat a record for the date of 88 that was set in 1951, while Sunday's high of 89 should top the previous high of 85 recorded in 1978, Seto said.
The region began warming Thursday as offshore winds start heating things up, Seto said.
Friday was expected to be warmer with winds continuing across Ventura and Los Angeles counties. Gusts of 30 to 40 mph were expected at the coast and in valleys with some 50-mph gusts in the mountains, according to a weather service forecast.
Saturday and Sunday will be calm but scorching, forecasters said.
It should be slightly cooler on Monday, but highs will still be well above normal, according to the weather service.
The weekend hot spell also won't do thirsty Southern California any good. "The main thing about the heat is that it's going to effect the evaporation at reservoirs ... and the snowpack," Seto said.
Water from melting Sierra Nevada snowpacks is a crucial part of Southern California's water supply, but recent surveys have found the snowpacks to be far below normal.
The heat wave continues a winter season that has seen an unusual number of warm months, Seto said. Longer-range global forecasts are suggesting that March, April and May probably also will see above-normal temperatures all along the West Coast, he said.
Los Angeles already is far below normal in rainfall. The wettest month, February, typically gets 3.8 inches of rain, but this year the total was well under an inch, Seto said. March has received 0.87 of an inch so far and is unlikely to get much more.
Los Angeles is more than 4 ½ inches of rain below normal for the water year that began on Oct. 1, Seto said.
"We haven't gotten anything near like what we need," he said. "Not good, and this is our fourth year going into this drought."