07/1125 PM.
Moderate heat impacts will continue through Friday away from the coast in response to a strong ridge over the region. Some relief from the heat is likely this weekend as the ridge breaks down and opens the door for possible monsoon showers or thunderstorms.
(tdy-Fri), 08/935 AM.
***UPDATE***
Sunny skies and hot weather on tap today, with the Heat Advisories still in place for areas away of the coast. Another round of Sundowner winds are expected tonight across Southwest Santa Barbara County, with gusts up to 55 mph possible. Thus, a Wind Advisory will be issued by the afternoon for that area.
Otherwise the short-term forecast is on track, and no changes were needed for the morning update in short-term forecast.
***From Previous Discussion***
An upper high will be centered over Srn CA today through Friday. Hgts will range from 594 to 596 dam, which is 3 to 4 dam higher than normal. There will be onshore flow to the east strongest in the afternoon, but a few mb weaker than it was earlier this week. There will be a mb or two of offshore flow from the north in the mornings turning weakly onshore to the north in the afternoons.
The marine layer has been smooshed down to about 800 ft by the hier than pressure aloft. The lack of an eddy means that there will only be minimal (if any) low clouds south of Pt Conception. The normal amount of onshore flow across the Central Coast will bring that area consistent night through morning low clouds today through Friday.
Max temps will be the main concern through the short term. The hier than normal hgts, lack of a solid marine layer and only weak to moderate onshore flow in the afternoon will all add up to warmer than normal conditions. Look for 3 to 6 locally 8 degrees of warming today under the subsidence from the upper high. This will bring vly highs of 92 to 103 degrees. Most max temps south of Pt Conception will be 4 to 8 degrees over normal. The Central Coast will only have near normal temps as the cooling sea breeze will greatly modify their temps. Most areas south of Pt Conception will see little change in temps on Thursday, but a weaker sea breeze will allow for 3 to 5 degrees of warming across the Central Coast. A 2 to 3 mb uptick in onshore flow on Friday will bring 3 to 5 degrees of cooling to the csts and vlys on Friday, but max temps will remain a few degrees over normals. A heat advisory is in effect for the LA vlys and interior cstl sections as well as all of the mtns and far interior vlys (please see the product LAXNPWLOX for all details).
Advisory level Sundowner winds are expected again this evening and Thursday evening for Southwest Santa Barbara County. Elevated fire weather conditions are expected for this area as well.
(Sat-Tue), 08/226 AM.
The upper high that will sit atop of Srn CA for the next three days will shift to the NE late Friday through Sunday. It will eventually reach the Dakotas. This movement will set up SE flow into Srn CA. At the sfc mdt to stg onshore flow will continue both to the N and E.
The SE flow will bring in monsoon moisture and there will be partly to mostly cloudy skies through the period as plenty of mid and high level clouds stream into and over the area. The moisture will not be low enough to create a convective threat on Saturday. For Sunday to Tuesday, however, the monsoon moisture will lower enough to bring a 10-20 percent chc of showers/isolated TSTMs to portions of LA and (less of a chc) VTA counties. The best chc of showers will be over eastern LA county and esp the eastern San Gabriels.
At the low levels, due to the increased onshore flow, night through morning low clouds and fog will affect most of csts and some portions of the lower vlys.
Look for 3 to 6 degrees of cooling on Saturday which will bring mid 70s to lower 80s to the csts (lower 70s at the beaches) and mid 80s to mid 90s in the vlys. These max temps are close to seasonal normals. There will be little day to day chg in temps Sun and Mon. Tuesday may warm a few degrees as the clouds thin out and the onshore flow relaxes a bit.
08/1711z.
At 1606z at KLAX, the marine layer was 800 ft deep. The top of the inversion was at 1400 ft deep with a temperature of 22 C.
High confidence in TAFs for KSBA, KBUR, KVNY, KPMD and KWJF.
Fair confidence in TAFs for KSBP and KSMX with a 25 percent chc of IFR conds redeveloping this evening around 5-7z and lasting through 16Z. VFR conds could occur +/- 1 hour from fcst.
Good confidence in TAFs for KOXR and KCMA with a 15 percent chc of IFR cigs 13Z-16Z.
Low confidence in TAFs for KSMO, KLAX, KPRB (40 percent chc of IFR cigs 10Z-17Z) and KLGB (40 percent chc of no cigs)
KLAX, Low confidence in TAF. There is a 40 percent chc of OVC008 conds 12Z-17Z). Good confidence that any east wind component will be AOB 5kt.
KBUR, High confidence in TAF.
08/239 AM.
High confidence in Small Craft Advisory (SCA) level NW winds persisting through at least Thursday across the Outer Waters. There is a 50-70% chance of Gale Force winds this afternoon and evening and again Thursday. Winds will likely be strongest near Point Conception and the Channel Islands, extending south to San Nicolas Island. Short- period, advisory level, choppy seas will gradually increase in height, reaching around 10 ft by mid- week and then subsiding below advisory levels Friday into the weekend.
SCA level NW-W winds will affect the inner waters along the Central Coast and the Santa Barbara Channel greatest during the afternoon and evening hours through at least Thursday. There is a 40% chance of Gales across the nearshore waters along the Central Coast and the Santa Barbara Channel in the afternoons/evenings through Thursday.
For the inner waters adjacent to Los Angeles County, moderate confidence in SCA level gusts through tonight. Otherwise, conds are expected to remain below SCA levels.
Ca, Heat Advisory remains in effect until 8 PM PDT Friday for zones 38-88-343>345-353-368-372-373-375>380-548. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Thursday for zones 645-650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 670-673-676. (See LAXMWWLOX). Gale Warning in effect from 3 PM this afternoon to 3 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX).
