23/851 AM.
High pressure anchored over the West will keep a hot air mass in place through early next week. The hottest temperatures are expected for late this weekend and through the weekend. Elevated risk for heat stress and heat illness will continue as the prolonged hot daytime and warm overnight conditions are expected through Monday. Gusty northerly winds will continue affect portions of the area through Friday.
(Thu-Sun), 23/834 PM.
***UPDATE***
High temperatures remained toasty over the interior with highs in the 100s for the Antelope Valley and 90s to low 100s for the valleys. The Central Coast highs were similar to yesterday's with 60s to low 70s common. Southern coastal areas were on the warmer side and highly variable, with some areas reaching the 80s and other spots in the 70s. Sundowner winds played a role in keeping the Santa Barbara south coast warmer today, and winds have strengthened again is this afternoon. Advisory level winds look a bit less widespread, but favored areas are seeing northerly winds of 20-35 mph with gusts up to 55 mph.
Looking ahead, temperatures were lowered for Friday and Saturday, especially along the Central Coast given how cool it was there today and with the expectation of breezy northwest winds and morning marine layer clouds. Other areas should still be quite warm through the weekend as high pressure remains in control. Otherwise, the current forecast looks on track. Will want to monitor the potential for convection over the Ventura County and LA County mountains Saturday and Sunday afternoon/evening.
***From Previous Discussion***
A broad upper-level ridge of high pressure, currently centered over the Borderland region, is starting to shift westward this afternoon. The ridge will recenter into the Four Corners region for late week, allowing more influence of the high pressure system on the weather pattern across the southern California region. 500 mb heights are expected to climb and onshore flow will weaken some across the region over the next couple of days. The hottest days are expected today and Friday when the mix of high heights combine with weakening onshore pressure gradients. 950 mb temperatures will warm by a degree or two each day through Saturday.
There is a moderate to high risk of heat illness over the next several days. A heat advisory remains in place for a majority of the coastal, valley, and mountain areas, while an extreme heat warning is in effect for the Antelope Valley floor. As the region sits on the edge of higher heat risk to the east, there is a moderate to high (30-50 percent) chance that localized extreme heat warning criteria could be met on Friday when the warmest temperatures are forecast. For those sensitive to the heat, such as the very young, the very old, those without air conditioning, and those active or working outdoors, the risk for heat illness is high.
A tighter northwesterly surface difference across the state will bring another round of Sundowner winds across the region late this afternoon through tonight. Breezy to gusty northwest to north winds across southern Santa Barbara County will develop tonight with the strongest winds expected again across the southwestern portion of the county. Motorists driving on area roadways, especially on Highway 101 between Gaviota and Goleta, should be aware of gusty cross winds that could develop and make driving difficult.
(Mon-Thu), 23/239 PM.
High pressure aloft will shift back to the east early next week and allow for some cooling. Stronger onshore flow should develop and bring a return of night through morning low clouds and fog to the coastal areas. 500 mb heights drop into mid week next week. Enough cooling should develop to bring down the heat advisories by Monday.
The main wrinkle could end being an easterly wave propagating under the ridge over the weekend. Some of the solutions push some moisture over the region, but the main question is enough energy will be present. A low but non-zero threat of monsoon convection will remain in the forecast over the mountains through the weekend.
High pressure aloft will remain in place and keep above normal temperatures in place through next week. Another round heat could develop for the end of next week.
23/2327z.
At 2159Z at KLAX, the marine layer was 800 ft deep. The top of the inversion was at 2700 ft with a max temperature of 28 C.
Moderate confidence in KPRB, KSMX, & KSBP.
KPRB: 15% chance of brief LIFR CIGs from 24/10Z-14Z. KSBP: 40% chance of LIFR/IFR CIGs from 24/03Z-11Z. KSMX: 60% chance of LIFR CIGs from 24/08Z-15Z.
High confidence in VFR conditions for remaining sites.
KLAX, High confidence in VFR TAF. No significant east wind component expected.
KBUR, High confidence in VFR TAF. No wind issues expected.
23/559 PM.
Widespread strong Small Craft Advisory NW winds are expected to continue across the Outer Waters thru at least the weekend. Periods of low-end GALE Force wind gusts are likely at times. A GALE Warning remains in effect through 3 AM Friday for all outer water zones. Additional warnings may be needed later. Seas will near 10 ft at times. SCA winds will spread into the nearshore waters along the Central Coast & western portion of the Santa Barbara Channel at times through the forecast period.
23/624 PM.
A long period, southern hemisphere swell will arrive early Saturday and will add to the continuing swell from Hurricane Fausto. This swell will result in an increased risk of dangerous rip currents across the coastal beaches, as well as elevated surf of 3-6 ft across the Los Angeles and Ventura County Beaches. Therefore, Beach Hazard Statements are in effect through the weekend for Los Angeles and Ventura County beaches and the Central Coast beaches. Rip currents and elevated surf will be strongest across south to southwest facing beaches and harbors such as Avila Beach.
The Eastern Pacific looks to remain active with tropical systems over the next couple of weeks. This could result in additional southerly swells to impact the coastline.
Ca, Heat Advisory remains in effect until 8 PM PDT Monday for zones 38-88-342>345-348>358-362-366>382-548. (See LAXNPWLOX). Beach Hazards Statement in effect from Friday afternoon through Sunday evening for zones 340-346. (See LAXCFWLOX). Wind Advisory in effect until 3 AM PDT Friday for zones 349-351. (See LAXNPWLOX). Beach Hazards Statement in effect through Sunday evening for zones 354-362-366. (See LAXCFWLOX). Extreme Heat Warning in effect until 8 PM PDT Monday for zone 383. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Saturday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until midnight PDT tonight for zone 650. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Friday for zones 670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect from 3 AM Friday to 3 AM PDT Sunday for zones 670-673-676. (See LAXMWWLOX).
