05/728 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 some of the interior valleys Tuesday through Thursday. a Heat Advisory is in effect for non-coastal areas starting at 10 AM Tuesday.
(Sun-Wed), 05/829 PM.
***UPDATE***
The main weather focus through much of the coming week will be high temperatures, in combination with gusty winds in some areas, and widespread elevated to brief critical fire weather concerns due to very warm and dry conditions.
Heights aloft will be rising through Wednesday before leveling off on Thursday, with decreasing onshore winds through the period. Highs will rise a few degrees on Monday, with more significant warming expected Tuesday and Wednesday as heights rise to 592 mb Tuesday, and up to 596 by Wednesday and Thursday. A Heat Advisory is in effect for all areas away from the coast from Tuesday morning through Thursday evening. Highs in the valleys and interior will rise into the upper 80s to around 100 degrees Monday, with 90s to lower 100s on Tuesday. By Wednesday the warmest valleys will be near or over 100 degrees, with 104 or higher over the Antelope Valley. Overnight lows will be unusually warm as well, especially over the foothills and lower mountain slopes where mid 70s will be common.
Onshore winds gusting up to around 35 mph will affect the Antelope Valley and foothills tonight and again Monday afternoon and evening. Sundowner winds are expected across southwest Santa Barbara County each late afternoon to overnight period through Wednesday, likely strongest Tuesday and Wednesday with gusts between 45 to 50 mph.
As for low clouds, the marine layer should be able to reform tonight, at least for coastal areas. The Santa Barbara South Coast should remain clear due to Sundowner winds, and this will continue each night through midweek as the Sundowners strengthen. Otherwise, low clouds will likely be limited to coastal areas for much of this week under building heights aloft.
(Thu-Sun), 05/200 PM.
Above normal temperatures are anticipated through the forecast period as high pressure shifts from southern California northeastward into the northern Rockies. This will result in a very warm start to the extended periods, with afternoon temperatures peaking Wednesday and Thursday afternoons, before some modest cooling is realized by Friday and into next weekend. This cooling will be a result of heights aloft beginning to fall as some weak disturbances in southeasterly flow begin to track across the region, possibly bringing some monsoonal moisture to parts of the area.
While there is some uncertainty on how warm coastal areas get Tuesday through Thursday, with potential advisories for these areas possibly eventually being needed, confidence is high that all areas will see above normal temperatures through next weekend with some potentially dangerous heat impacting at least parts of the area through Thursday.
Late in the period, models are indicating that a monsoonal flow pattern will set up across the southwest with southeasterly flow steering multiple disturbances across the local area as early as this weekend and into the following week. While the current forecast remains dry, this could eventually justify the mention of some showers and thunderstorms across the higher terrain and deserts by next Monday as both the EC/GFS are indicating some light qpf across these areas.
06/0009z.
At 2230z at KLAX, the marine layer was 700 ft deep. The top of the inversion was 2000 ft deep with a temperature of 22 C.
High confidence in VFR TAFs for desert airfields (KWJF & KPMD).
Low to moderate confidence in remaining TAFs. Timing of flight cat may be off +/- 3 hours and CIG heights +/- 300 ft. Confidence in CIG forecast for KOXR, KCMA, KSMO, KLAX, & KLGB is lowest due to disorganized marine layer stratus. There is a 30% chance that CIGs do not arrive/form or remain brief late tonight into tomorrow morning.
KLAX, Moderate confidence in TAF. High confidence in VFR conds through 06/06Z. Low confidence from 06/06Z-18Z due to likely disorganized stratus, with a 30% chance that CIGs do not arrive or brief at times. No significant easterly wind component expected.
KBUR, Moderate confidence in VFR TAF. No wind issues expected.
05/829 PM.
High confidence in Small Craft Advisory (SCA) level NW winds persisting through at least Thursday across the Outer Waters. There is a 20-30% chance of GALE Force winds Tuesday afternoon through Thursday. Winds will likely be strongest near Point Conception, Channel Islands, and the far northern outer waters. Seas will gradually increase reaching advisory levels mid- week and will subside below Friday into the weekend.
SCA level NW-W winds will reach into the inner waters along the Central Coast and the Santa Barbara Channel starting Monday afternoon through Wednesday or Thursday. Most likely and strongest overnight during the afternoon and evening hours. Local gusts could reach 21 kts during the late afternoon-evening hours near Point Dume and across the San Pedro Channel through Tuesday or Wednesday.
Ca, Heat Advisory in effect from 10 AM Tuesday to 8 PM PDT Thursday for zones 38-88-343>345-353-372-373-375>380-548. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from 3 PM Monday to midnight PDT Monday night for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect from 5 PM Monday to 5 AM PDT Tuesday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 5 AM PDT Tuesday for zones 673-676. (See LAXMWWLOX).
