A strengthening upper-level ridge
of high pressure is the culprit - or the benefactor, depending on your view of extremely hot weather - for the continued high temperatures.
The heat is the result of an upper-level ridge
of high pressure that began building Saturday and centered over Southern California, according to the NWS.
An upper-level ridge
of high pressure - a really strong one - has built up over us, moving basically from the southeast Nevada desert," said meteorologist Wanda Likens at the Weather Service office in Portland.