18/215 PM.
Steady cooling through Friday with below normal temperatures continuing through the weekend. There will ample low clouds each morning through the weekend. Gusty onshore winds will affect interior areas through the next week and will be strongest Friday. A significant warming trend remains on track for next week with heat impacts expected.
(tdy-Sun), 18/131 PM.
Marine layer stratus clouds have been slow to clear today, especially across Ventura and LA counties. This is due mostly to strong onshore flow, helping increase the depth of the marine layer - up to 3000-4000 ft this morning - and push the stratus further inland. A coastal eddy south of Point Conception may also be contributing to the persistent low clouds. Everywhere below the lingering stratus/stratocumulus was still experiencing temperatures mostly in the 60s at noon today. The longer the clouds linger over some of the inland valleys the less likely the temperatures are to reach upper 70s to lower 80s and some of the areas closer to the coast may only reach the upper 60s.
The June Gloom trend will continue through the short term with moderate to strong onshore flow and the deeper marine layer forecast to continue through this weekend. There may be enough lift esp near the foothills to produce some morning drizzle. Clearing will be slow today and many beaches will not clear at all esp across VTA county.
The upper level flow will turn weakly cyclonic on Friday with a shortwave trough moving through and will then become zonal on Saturday. Hgts will remain near 588 dam through the period. Much more importantly will be the strong onshore flow both to the N and E. The push to the east will be near 10 mb each afternoon.
The passing shortwave Friday combined with the already strong onshore flow and deep marine layer should induce slightly stronger southwesterly downsloping winds into the Antelope Valley compared to previous days which saw peak gusts up to 35-45 mph. A Wind Advisory has been issued for Friday afternoon with the anticipated slight uptick in magnitude.
A cooling trend will continue through Friday, with afternoon max temperatures cooling another 1-3 degrees compared to today. Only a few of the warmest vly locations will see highs reach or eclipse 80 while the rest of the area sits in the 70s (the nearshore area will actually not escape the 60s). Max temp will change little on Saturday (perhaps a few degrees of warming across San Obispo County) as the area remains swaddled by the cool marine air and zonal flow. A few degrees of warming is expected on Sunday as guidance shows onshore flow weakening slightly and H5 heights rising slightly.
(Mon-Thu), 18/212 PM.
Zonal flow will continue over the area through at least Monday morning before anticyclonic flow develops as an upper level high strengthens ESE of SoCal. The onshore flow will weaken just a little bit. This should decrease the morning cloud coverage a little bit and allow for somewhat better and faster clearing. Look for around 3 to 6 degrees of warming is possible Monday as hgts rise a little and compresses the marine layer.
Models have backed off a little on the degree of warming slated for next Tue-Thu. Hgts should still warm to an above normal with global ensembles supporting 593-596 dam, which will be around the 90th-95th percentile of climatology. At the sfc, mdt-stg onshore flow will persist in the W to E direction, but the onshore push to the north will weaken through the period. The higher hgts will likely smoosh the marine layer to 1000 ft or less which will greatly reduce the amount of clouds making it into the vlys in the mornings. This compression will strengthen the marine inversion which will hinder the clearing near the shore. The current forecast calls for 2 to 4 degrees of warming each day Tue and Wed with little change on Thursday. This warming would bring vly temps into the mid 80s and lower 90s. Latest NBM has good chances (50%) of reaching 100 degrees across the Antelope Valley and even slight chances (10%) in Paso Robles Wed-Fri. An Extreme Heat Watch was issued for Tue-Thu for parts of LA County, including LA, with temperatures expected to reach the 80s, to around 90 east of Downtown LA. With an influx of people, especially those not from the area, and events the risk of heat impacts will be greater, despite forecast HeatRisk magnitudes of high-end Minor to low-end Moderate.
18/1656z.
At 1636Z at KLAX, the marine layer was 1700 ft deep. The top of the inversion was near 4000 ft with a temperature of 19 Celsius.
High confidence in KPMD & KWJF.
Fair confidence in TAFs - VFR transition could be up to 2 hours later than fcst.
KLAX, Moderate confidence in TAF. VFR conds may arrive any time 19Z-22Z. No significant east wind component expected.
KBUR, Moderate confidence in TAF. VFR conds may arrive any time 18-19Z.
18/250 PM.
Fairly high confidence in winds and seas staying below Small Craft Advisory (SCA) criteria through Saturday, but typically gusty winds of 15 to 20 knots will form each afternoon and evening, mainly over western portions of the Santa Barbara Channel and southward to San Miguel Island. Lower confidence after Saturday.
18/241 PM.
A long period south to southwest swell (14 seconds and 16 seconds) will continue to affect the coastal waters through at least Friday. A Beach Hazard Statement is in effect through Thursday evening due to elevated surf of 3 to 5 feet on south- facing beaches of Ventura County Beaches, Malibu Coast, and Los Angeles County Beaches. Portions of the Southern Santa Barbara County Beaches could see surf to 2 to 4 feet.
High tides will continue to lower and should stay below 6.5 feet MLLW. The coastal flooding risk has lowered significantly as a result.
Ca, Extreme Heat Watch in effect from Tuesday morning through Thursday evening for zones 88-368-372-373-379-380-548. (See LAXNPWLOX). Beach Hazards Statement in effect through late tonight for zones 349-350-354-362-366. (See LAXCFWLOX). Wind Advisory in effect from 1 PM to 10 PM PDT Friday for zones 381-383. (See LAXNPWLOX). PZ, NONE.
