06/1131 PM.
Weak onshore flow will continue to bring limited low cloud cover to the coasts and coastal valleys each night through morning over the next several days as temperatures warm across the region. Interior temperatures will likely reach 100 degrees or higher across the interior valleys today through Friday. A Heat Advisory is in effect for non-coastal areas starting at 10 AM today and starting at 10 AM Wednesday for the Los Angeles County Inland Coast - including Downtown Los Angeles.
(tdy-Thu), 07/1034 AM.
***UPDATE***
The warm up continues today with 2-5 degrees of warming over the past 24 hours focused away from the coast and especially Los Angeles and Ventura Counties. The Heat Advisory for many interior areas start today, but the peak of the heat for most areas will be Wednesday and Thursday. We will need another wind advisory this evening for Southwest Santa Barbara County where winds may peak about 5 mph stronger than yesterday evening.
***From Previous Discussion***
Srn Ca is under the western side of a 595 dam upper high centered near the 4 corners. Hgts over Srn CA are near 592 dam. Onshore flow this morning will be weakly onshore to the east and weakly offshore from the N. The combination of high hgts and weak flow will only allow patchy low clouds to develop south of Pt Conception. A little strong onshore push up north has brought a blanket of low clouds to the Central Coast. Weaker than normal onshore flow and higher than normal hgts will team up to bring 1 to 3 degrees of warming to the area today. Many areas will end up 3 to 5 degrees above normal today.
The upper high shifts westward and over Srn CA on Wednesday. This will raise hgts to 594 dam. Weak onshore flow will continue and the marine layer will continue to be patchy across the csts S of Pt Conception (still expecting a pretty solid stratus deck across the Central Coast). This will make Wednesday the warmest day of the next 7 with 2 to 4 locally 6 degrees of warming on tap. Look for highs in the mid 90s to 102 in the vlys, 105 to 107 degrees in the Antelope Vly. Even the normally cool coasts will see highs in the mid 80s. Due to the heat head advisories are in effect for all of the mtns and interior vlys as well as all of the LA county Vlys and the LA county interior coastal section. Please see the product LAXNPWLOX for all of the details.
There will not be much change in the weather on Thursday. The upper high will remain overhead and a little further atmospheric warming will bring a degree or two of warming to the mtns and far interior. The vlys will see little change. The coasts may cool a couple of degrees as a slight increase in the afternoon onshore push will bring a little stronger and earlier sea breeze.
Gusty Sundowner winds will develop across the southwest coast of Santa Barbara county each evening. Wind advisories are likely for the SW corner of SBA county each evening and overnight.
(Fri-Mon), 07/209 AM.
During the xtnd period the upper high will drift to the NE through Sunday and then will set up camp over South Dakota. This high will grow in size and the state will remain under the western flank of the high. Hgts will fall from 592 dam on Friday to 590 dam on Sunday, Hgts will then increase again Monday as the upper high grows even larger. The bigger news will be the increase in onshore flow on Friday. This will generate more marine layer stratus in the morning and a stronger sea breeze. Max temps will fall 3 to 6 degrees and many coastal areas will see blo normal temps.
The Saturday through Monday fcst will be a little different. The upper highs new location will set up SE flow over Srn CA. This flow will bring in monsoon moisture through the three day period. Just high level moisture on Saturday, but enough moisture in 8000-10000 ft region on Sunday and Monday is enough to allow for a slight chc of some convection (best chc over the LA mtns) esp if an easterly wave develops. In addition to the slgt chc of showers or TSTMs the monsoon flow will bring partly to mostly cloudy skies which will help keep max temps from changing much from Friday's values.
07/1712z.
At 1622z at KLAX, the marine layer was 1100 ft deep. The top of the inversion was 6100 ft deep with a temperature of 21 C.
High confidence in VFR for KVNY, KPMD and KWJF.
Moderate confidence in TAFs for KPRB, KSMX and KSBP where MVFR transition may be off by 90 minutes this evening.
Moderate confidence in TAFs for KSBA, KOXR and KCMA where there is a 25 percent chc of IFR cigs 11Z-17Z.
Low confidence in TAF for KSMO with a 40 percent chc of IFR cigs 11Z-16Z tonight.
Moderate Confidence in TAFs for KLGB and KLAX. There is a 40 percent chc of no low clouds developing this evening. Arrival and clearing times could be off by as much as 90 minutes.
KLAX, Moderate confidence in TAF. There is a 40 percent chc of no low clouds developing this evening. Low clouds could arrive as late a 14Z. Good confidence that any east wind component will be AOB 5kt.
KBUR, High confidence in TAF.
07/210 AM.
High confidence in Small Craft Advisory (SCA) level NW winds persisting through at least Thursday across the Outer Waters. There is a 40-60% chance of GALE Force winds this afternoon through 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 during the afternoon and evening hours through Wednesday or Thursday. There is a 40-60 percent chance of GALES Tuesday and Wednesday in the western Santa Barbara Channel, and a 40-50% chance of Gales along the Central Coast Wednesday and Thursday.
For the inner waters adjacent to Los Angeles County, moderate confidence in SCA level gusts through Tuesday night. 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>345-353-372-373-375>380-548. (See LAXNPWLOX). Heat Advisory remains in effect from 10 AM Wednesday to 8 PM PDT Friday for zone 368. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Wednesday for zones 645-670. (See LAXMWWLOX). Small Craft Advisory in effect until 2 PM PDT this afternoon for zones 650-673-676. (See LAXMWWLOX). Gale Warning in effect from 2 PM this afternoon to 3 AM PDT Wednesday for zones 650-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 10 PM PDT this evening for zone 655. (See LAXMWWLOX).
