An area of high pressure will remain over the Desert Southwest through much of the upcoming week, leading to a prolonged period of hot daytime temperatures and warm nights mainly west of the mountains. Breezy Santa Ana winds will continue today and Sunday, highest near the coastal-facing mountain slopes. The peak of the heat will be this weekend, but confidence is still low on how long the heat lasts into the end of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
Santa Ana winds have been observed this morning. East flow around an area of high pressure has resulted in gusts near 30-45 MPH across the San Diego County mts/foothills. Gusty winds and lower relative humidity each day will lead to elevated to near-critical fire weather conditions, so make sure to do your part that leads to one less spark! East winds have even made it to the coast this morning, shooting temperatures up into the 90s along the beaches. Onshore winds will start to take hold this afternoon, knocking temperatures down 5-10 degrees.
Hot weather will continue into early next week, as an area of high pressure anchors over our region. Today and Sunday will likely be the warmest days as weaker offshore flow prevails. The high will weaken slightly and move more toward the southwest as we go into the early part of next week. This will allow increased onshore flow closer to the coast, bringing a few degrees of cooling. Nights will still remain warm for many areas in the lower to mid 70s west of the mountains. The mountains and deserts will still be warm for this time of year with highs near 5 to 10 degrees above normal, but not as intense as places west of the mountains. Mountain areas like Julian and Big Bear will be in the 70s and 80s for most of this event. Areas 3000-6000 ft will also see low temperatures well above normal. Please make sure to be in areas of A/C and check on those without effective cooling.
By Friday, most models begin to diverge on the high starting to weaken as a trough to the north begins to enter the Pacific NW. The progression of this trough is still uncertain, and will help determine how cool we get by the end of next week. By Friday, greater onshore cooling looks to spread inland helping to lower temperatures mainly into the 80s and 90s west of the mountains. Further cooling may occur if the trough is strong enough to push further south into California by next weekend.
040000z, Coast/western valleys: SKC and VFR through the period. E/SE winds gusting 10-20 kts could reach parts of the coast from 15- 19z Sun, including at KSAN and KCRQ, then turn onshore W/NW Sun afternoon.
Inland Valleys/Foothills/Mountains: East winds weaken inland, remaining elevated over higher west facing slopes near mountain ridges tonight. E/SE winds increase and expand westward to valleys in the early morning hours ~11-15z, peaking between 15-19z with gusts to 15-30 kts (locally to 35 kts). MOD UDDFS expected over coastal slopes. Winds gradually turn westerly Sunday afternoon through the valleys as the sea breeze moves inland.
Otherwise, Clear skies through the TAF period.
No hazardous marine conditions are expected through Wednesday.
Ca, Extreme Heat Warning until 8 PM PDT Thursday for Orange County Coastal Areas-Orange County Inland Areas-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Coastal Areas-San Diego County Valleys-Santa Ana Mountains and Foothills.
Wind Advisory until 6 PM PDT this evening for Orange County Inland Areas-Riverside County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains-San Diego County Valleys-San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.
PZ, None.
