Near-record high pressure for late August will continue hot days and near-record warm nights through Friday night with a slight chance of showers and thunderstorms for the mountains for this afternoon and Friday afternoon. High pressure will weaken for the weekend into early next week with high temperatures cooling to around average on Monday of next week. For Tuesday and Wednesday of next week, there is a 10 to 20 percent chance for an increase in clouds and a chance of precipitation from a tropical system that has yet to develop.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
(today through Saturday), High temperatures will remain around 10 degrees above average through Friday with high temperatures ranging from the 80s at the beaches to 100 to 110 for the Inland Empire with 112 to 116 for the lower deserts. Nights will remain quite warm through Friday night with near-record warm overnight temperatures, mostly in the 70s for the coast and valleys and in the mid 80s to mid 90s for the lower deserts. Major to Extreme HeatRisk will continue through Friday for the lower deserts, inland valleys, and inland Orange County.
Monsoonal moisture will maintain a slight chance of afternoon showers and thunderstorms for the mountains through Friday. Temperatures will begin to cool a few degrees on Saturday as high pressure across the area begins to weaken.
(Sunday through Wednesday), The cooling trend will continue into early next week, but with increasing spread in the temperature guidance after Monday. High temperatures and low temperatures on Monday will be a few degrees below average with high temperatures on Monday ranging from the mid 70s to lower 80s near the coast to the 90s for the Inland Empire with 104 to 108 for the lower deserts.
For Tuesday and Wednesday, there could be an increase in clouds and a chance of precipitation from a tropical system that has yet to develop. The center of that possible tropical system would remain well to the southwest of the area, but a low pressure system near the West Coast could direct some mid and high level moisture and clouds from that possible tropical system toward the northeast and toward California.
271130z, Coast, Areas of low clouds based 200-800 feet MSL with vis reduced 0-6SM will be intermittent and random but most likely in San Diego County through 16Z. Fewer low cloud cigs are expected tonight after 05Z into Friday. Any cigs/vis would be similar.
Mountains/Deserts, Cumulus based around 9000 feet MSL will develop after 19Z along with isold CB cloud tops rising to 40000 feet MSL. There is a 15-20% chance of TSRA over the mountains and a 5-15% chance in the deserts 20-01Z. Any TS that develops could produce gusty, erratic winds.
Regionwide, High clouds AOA 15000 feet MSL will continue today and tonight, decreasing early Friday.
No hazardous marine conditions are expected through Monday.
A 4-foot southerly swell (from 170 degrees) at 12-13 seconds will continue to produce elevated surf today and tonight, particularly for south-facing beaches of Orange County and northern San Diego County. Surf of 3 to 5 feet, with sets up to 7 feet is expected. Check the Coastal Hazard Message for details on beach hazards.
Ca, Heat Advisory until 8 PM PDT Friday for Orange County Coastal Areas-Riverside County Mountains-San Bernardino County Mountains-San Diego County Coastal Areas.
Beach Hazards Statement through this evening for Orange County Coastal Areas-San Diego County Coastal Areas.
Extreme Heat Warning until 8 PM PDT Friday for Apple and Lucerne Valleys-Coachella Valley-Orange County Inland Areas-San Bernardino and Riverside County Valleys-The Inland Empire- San Diego County Deserts-San Diego County Mountains-San Diego County Valleys-San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.
PZ, None.
