Strong high pressure aloft and locally gusty northwest winds will result in hot and dry conditions away from the coast through Sunday. The heat will peak Friday and Saturday. Heat-related illnesses and fire weather concerns exist. Meanwhile, dense fog will slow warming at the coast. A cooling trend is expected Sunday through Wednesday, with a return to normal by Tuesday.
The heat wave is still on track over the mountains and warmer valleys, but more unsure of the coast and some valleys due to uncertainty in the marine layer. Friday still looks the hottest overall, but saturday does not look much different and could be even a touch warmer over San Luis Obispo and Santa Barbara Counties. High pressure aloft, currently centered over western Arizona will change little through Saturday. North to south flow will also increase each night and enhance the warming and decreasing marine layer trend, with wind gusts between 20 and 40 mph over southern Santa Barbara County.
A heat advisory through Saturday night is in effect for most valleys and mountains as max temperatures in the warmest valleys and mountains should range between 97 and 107. Coastal areas will warm up as well but not as dramatically with highs in the mid 70s to high 80s for Friday, Saturday and Sunday.
Sunday will remain warmer than normal, but should be 3-6 degrees cooler than Saturday as the high shifts southward and the onshore flow strengthens. Also expecting the marine layer to increase in and coverage some as a result.
The upper level high currently fueling our heat wave, will continue to weaken and slide away from California Monday through Thursday, being replaced by a weak upper level trough. This should all add up to steady and gradual cooling, with temperatures and the marine layer generally back to normal by Tuesday