High Heat and Fire Risk: Los Angeles to San Francisco

By Anthony Sagliani, Meteorologist
September 30, 2012; 10:00 AM ET
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Construction worker Richard Villa takes a drink to cool off from the sweltering heat in downtown Los Angeles on Thursday June 19, 2008. Southern California roasted Thursday in a record-breaking, end-of-spring heat wave that sent temperatures soaring past 100 degrees in many areas, posing hazards for anyone who ventured outside. (AP Photo/Nick Ut)

As high pressure in the middle and upper reaches of the atmosphere strengthens, the result will be a period of extreme heat over California on Sunday through Wednesday.

This high pressure will promote a weak to moderate offshore wind, which will blow hot air straight to the coast and beaches.

Temperatures will range anywhere from 10-20 degrees above normal for Sunday through Wednesday, and some places will have temperatures upwards of 25 or 30 degrees above normal.

As Ken Clark, AccuWeather's Western Weather Expert, puts it, "records will be challenged Sunday through Wednesday."

According to Clark, "Temperatures in Southern California will rise well into the 90s for the coastal cities on Sunday, with the valleys climbing well above the 100-degree mark. On Monday and Tuesday, the heat will peak with temperatures hitting the middle to upper 90s to near 100 along the coastal plain. The valleys will likely approach 104-110."

Clark also states that the central valleys of California, as well as the central California Coast and Bay Area, will hit the 90s to low 100s.

In fact, it is likely that this will be the hottest weather in San Francisco since June, and may be the hottest it has been all year.

In addition to the dangerous heat, offshore winds will create a high fire danger, especially for Southern California.

Relative humidity levels will plummet to less than 10 percent in many locations. With most of the region abnormally dry, a mere spark could ignite a fire. Throw in gusty afternoon and evening winds, and an explosive fire threat will be present.

Be sure to keep checking back with AccuWeather.com for the latest on the upcoming heat and fire situation, and for all your weather needs.


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