The reason for the heat wave in Placer County and throughout the state? It's sitting high over Nevada

The reason for the heat wave in Placer County and throughout the state? It's sitting high over Nevada It's called a "three-legged stool" – excessive heat, poor overnight recoveries and duration of the event. That's how a National Weather Service meteorologist in Sacramento described the current heat wave that has seen temperature records broken in the Sacramento Valley and throughout the state. Auburn recorded a high of 98 degrees Monday (short of the Aug. 17 record of 106 in 1920) and 96 on Tuesday (the Aug. 18 record is 105, set in 1950). "It's a serious heat wave," Rowe said. The excessive heat warning extends through 9 p.m. Wednesday, followed by a reprieve, Rowe said Wednesday morning. But 100-degree days are forecast to return by Saturday. Rowe explained the "root cause" is a massive upper-level high-pressure system over Nevada, "strong and broad," as he put it; so strong that excessive heat warnings have extended as far north as Washington state. Temperatures have been as much as 20 degrees over normal in some places. "Any time you get in that territory, it's bad news," Rowe said. Also, the usual marine layer along the coast has been missing, resulting in high overnight temperatures. "We normally get a Delta influence that breaks the heat," Rowe said. Through Sunday, there were 29 days at or above 100 degrees in Sacramento, and, "We will add six or seven days to that," Rowe said. The mean number in Sacramento for the last 30 days is 23 100-degree days. The record for consecutive 100-degree days in Sacramento is 11, recorded in 2006. There were also thunderstorms throughout the northern Sacramento valley and Bay Area. Rowe said there were numerous reports of lightning-caused fires, including several in Nevada County.