The heat will begin to lessen going into the weekend with slight cooling of high temperatures for today with high temperatures cooling to around average on Friday and continuing around average into early next week. Monsoonal moisture in south to southeast flow aloft will begin to return today and slowly increase into the weekend, then slowly decrease into early next week. There is a slight chance of showers and thunderstorms each afternoon for the mountains onto the desert slopes of the mountains into next week with 10 to 20 percent chance for this afternoon and a 15 to 25 percent chance for Friday afternoon.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
(today through Saturday), Widespread moderate HeatRisk will continue for much of the area today except near the coast and in the higher elevations in the mountains with major HeatRisk in portions of the lower deserts.
High temperatures will cool a few degrees today with high temperatures around 5 degrees above average. High temperatures for today will range from the mid to upper 70s near the coast to the mid 90s to 104 of the Inland Empire with 108 to 112 for the lower deserts.
There will be greater cooling on Friday with high temperatures returning to around average for Friday through Monday of next week. High temperatures will range from the 70s near the coast to the upper 80s to mid 90s for the Inland Empire with 104 to 108 for the lower deserts.
Monsoonal moisture in south to southeast flow aloft will return today with a slight increase in moisture into the weekend, then a slight decrease into early next week.
There will be a slight chance of showers and thunderstorms each afternoon, mainly for the mountains onto the desert slopes of the mountains with a 10 to 20 percent chance for this afternoon and a 15 to 25 percent chance for Friday afternoon. The REFS 90th percentile hourly rainfall is around 0.50 to 1 inch from any isolated thunderstorms.
(Sunday through Wednesday), High temperatures will remain around average through Monday, then may warm a few degrees on Tuesday and again on Wednesday as high pressure aloft strengthens. With the warming, high temperatures on Wednesday would be a few degrees above average with high temperatures ranging from the mid 70s to near 80 near the coast to the 90s for the Inland Empire with 104 to 108 for the lower deserts.
For the middle of next week, there are some differences with high pressure across the area and the resulting strength of east to southeast flow and moisture transport into the area. Those solutions that have an axis of high pressure extending westward across the area from strong high pressure over the central and southern Rockies and Great Plains have the stronger east to southeast flow and resulting greater moisture transport into the area. Those solutions that have separate centers of high pressure over the central and southern Rockies and Great Plains and over the eastern Pacific are weaker with the east to southeast flow across the area with less moisture transport into the area.
160930z. Coast/Valleys, Very patchy low clouds with bases 600- 900ft MSL are present along the coast, most widespread in southern San Diego Co. There is about a 20%/40% chance for KCRQ/KSNA respectively to see CIGs through 15Z; clouds inland will clear by 16Z. Otherwise, periods of FEW-SCT high clouds AOA 15,000ft MSL and southerly breezes today. For this evening, there is a higher chance for more widespread, albeit still patchy, low clouds after 08Z Fri. Highest chances again for KSAN, with 30-40% chance at KCRQ/KSNA. Similar bases and vis to this morning are expected.
.Mountains/Deserts, Periods of high clouds AOA 15,000 ft and VFR conditions. SCT Cu based around 12,000ft MSL along with ISO TSRA over mountain ridges this afternoon after 21Z through about 03Z Fri.
No hazardous marine conditions are expected through Monday.
High amplitude southerly swell (4-5 ft) will arrive late this weekend, bringing elevated surf and strong rip and longshore currents for Sunday into early next week. Highest surf will be along south and southwest-facing beaches.
Ca, Heat Advisory until 8 PM PDT this evening for Orange County Coastal Areas-San Diego County Coastal Areas.
Extreme Heat Warning until 8 PM PDT this evening for Coachella Valley-Orange County Inland Areas-Riverside County Mountains-San Bernardino County Mountains-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.
