Strong high pressure will continue the warming today with widespread moderate or greater HeatRisk for inland areas into Friday with widespread major HeatRisk for the lower deserts through Thursday. For Sunday into next week, monsoonal moisture in southeast flow aloft will increase the humidity and bring chances for showers and thunderstorms with the greater chances over the mountains each afternoon and early evening.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
, High pressure aloft will continue to strengthen across the area today with forecast 500 mb heights later today above the 95th percentile, but not quite record setting for the date. High pressure will then slowly weaken through Thursday night before beginning to restrengthen on Friday. Widespread moderate or greater HeatRisk will continue for the Inland Empire, mountain elevations below 6000 feet, and the deserts through Friday with widespread major HeatRisk for the lower deserts through Thursday. The Excessive Heat Warning for the lower deserts and Heat Advisories for the Inland Empire and mountain elevations below 6000 feet through Thursday may need to be extended through Friday.
High temperatures for today will warm and few to around 5 degrees for inland areas with not much change on Thursday. High temperatures on Friday will only cool slightly. High temperatures for today and Thursday will range from near average at the coast to 5 to 10 degrees above average for the mountains, deserts, and inland valleys. High temperatures for today and Thursday will range from the 70s near the coast to the mid 90s to 105 for the Inland Empire with 112 to 118 for the lower deserts. While these high temperatures are expected to mostly remain below daily high temperature records, there could be a few record warm low temperatures in the mountains.
The marine layer will continue to become slightly shallower with night and morning coastal low clouds spreading into the far western valleys at times.
(Saturday through Tuesday), The center of high pressure aloft across southern California into Arizona on Friday will strengthen and move toward the northeast over the weekend. The flow aloft across the area will become southeasterly over the weekend into early next week with monsoonal moisture increasing for Sunday into early next week. Over the past couple of days, ECMWF ensemble precipitable water values have trended higher while the spread between wetter and drier ensemble members has narrowed. There will be a slight chance for showers on Sunday with greater chances for shower and thunderstorms over the mountains on Monday afternoon. Chances for afternoon and early evening thunderstorms for the mountains could continue through at least the middle of next week.
081730z. Coast/Valleys, Low clouds have cleared inland locations but are hanging onto the OC coast and a few areas of the SD coast. These low clouds based around 1,400ft MSL should clear at least OC in the next hour with a 30-40% chance of it sticking along areas of the SD coast through 20Z. VFR conditions will prevail through 02-04Z when low clouds with bases 700-1,100ft MSL will start developing along SD coast. Low clouds will increase in coverage and push north and inland up to 20 miles 07-09Z. Clouds will begin to clear inland locations after 15Z, clearing most coastal sites by 18Z.
.Mountains/Deserts, VFR conditions prevail through the TAF period.
No hazardous marine conditions are expected through Tuesday.
Astronomical high tides of 7.0-7.2 ft are forecast July 12-14. Higher than normal tides combined with a modest south swell (3 ft swell 14/15 seconds from 190 degrees) generating surf of 4-6 ft may result in areas of coastal flooding in low lying areas, boardwalks, beach parking lots, and beach adjacent streets during evening high tides.
Ca, Heat Advisory until 8 PM PDT Thursday for Riverside County Mountains-San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains.
Extreme Heat Warning until 8 PM PDT Thursday for Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, None.
