Strengthening high pressure aloft and offshore flow will bring much warmer high temperatures for coastal areas into the western valleys today will a long-duration heatwave expected to last through much of next week. Easterly Santa Ana winds for today will gust to 30 to 40 mph with winds on Saturday gusting to 35 to 45 mph with isolated gusts to 55 mph for the San Diego County mountains and inland valleys. Moderate or greater HeatRisk is expected for the coast and valleys through next Thursday with Major HeatRisk for the coast into the western valleys for today and Saturday and Extreme HeatRisk for locations just inland of the beaches into the western valleys for Sunday through Thursday. Nights will be quite warm for the coast and valleys with low temperatures for Saturday through Tuesday mostly in the 70s. Gradual cooling could develop around Friday of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
(today through Sunday), Strengthening high pressure aloft and offshore flow will bring much warmer high temperatures for coastal areas into the western valleys today will a long-duration heatwave expected to last through much of next week. High temperatures for today will range from around 90 at the beaches to 100 to 105 for the western valleys with Major HeatRisk for the coast into much of the valleys. Easterly Santa Ana winds will develop this morning and continue into early this evening with gusts to 30 to 40 along the coastal slopes of the mountains in Riverside and San Diego Counties into the adjacent inland valleys.
High temperatures on Saturday will be 15 to 20 degrees above average for the coast and valleys, locally exceeding 25 degrees above average for San Diego County coastal areas on Saturday. High temperatures on Saturday for the coast and valleys will be mostly in the 90s to around 105 with the hottest temperatures for inland coastal areas into the western valleys. Easterly Santa Ana winds are expected to be stronger and more widespread on Saturday with gusts to 35 to 45 mph, locally to 45 to 55 mph for the San Diego County mountains into the adjacent inland valleys. These winds will strengthen around sunrise, then diminish from north to south during the afternoon and early evening. Winds for Sunday are expected to be weaker and more localized.
Low temperatures for the coast and valleys for early today will be mostly in the 60s and lower 70s. Low temperatures will warm into the 70s for Saturday and Saturday. HeatRisk on Saturday will be similar to today with Extreme HeatRisk on Sunday for coastal areas into the western valleys.
(Monday through Thursday), With the weakening of offshore flow, a weak sea breeze will begin to spread some cooling into coastal areas with high temperatures near the beaches cooling into the mid 80s with more elevated and inland coastal areas still warming into the mid to upper 90s. High temperatures for the valleys will be mostly into the mid 90s to 105. Low temperatures for the coast and valleys will gradually cool into the upper 60s to mid 70s for Wednesday and Thursday. Extreme HeatRisk will continue through Thursday from just inland of the beaches into the western valleys with Moderate to Major HeatRisk elsewhere for the coast and valleys.
Some gradual cooling may develop beginning around Friday of next week.
020930z, Coast/western valleys: Patchy low clouds/fog have formed along parts of the coastline this morning. Bases 300-700 ft MSL are leading to vis reductions 0-3SM. Clouds will continue to be somewhat patchy and intermittent through the morning before clearing 15-16Z. Clear skies follow through the period as offshore winds aloft prevent low cloud formation this evening.
Inland Valleys/Foothills/Mountains: East winds increase over west- facing foothills, inland valleys and in parts of the Inland Empire after 17Z, gusting 25-40 kts by this afternoon. Winds diminish after 01Z Sat.
Otherwise, Clear skies through the TAF period.
No hazardous marine conditions are expected through Tuesday.
Ca, Extreme Heat Warning from 10 AM this morning to 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 from 6 AM to 6 PM PDT Saturday 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.
