14/237 AM.
A Santa Ana wind pattern will create much warmer temperatures this week as well as gusty northeast winds at times, strongest Thursday and Friday. Another significant cool down is likely into next week.
(tdy-Fri), 14/927 AM.
***UPDATE***
Offshore gradients continue to increase today and the more sensitive sites in the mountains are already getting north to northeast winds between 40 and 50 mph. We're even seeing north winds in the western San Fernando Valley gusting to 25-35 mph. Those will weaken this afternoon as the sea breeze returns but still expecting a bigger and more widespread increase in Santa Ana winds Thursday through Saturday, peaking Friday.
***From Previous Discussion***
Today will be a very pleasant day but all eyes are on the strong Santa Ana wind event starting Thursday.
High Wind Watches, Wind Advisories and Red Flag Warnings cover the Santa Ana Wind Corridor Thursday and Friday. A Fire Weather Watch is also in effect Friday for the Santa Barbara and San Luis Obispo interior mountains. A Heat Advisory is also in effect Thursday through Saturday for Coastal areas. Please see weather.gov/lox to view individual product details.
Ydy's inside slider has moved east into AZ and NW flow with 582 dam hgts will cover the state. At the sfc there will be about 1 to 3 mb of offshore flow from both the E and N (strongest from the north) There is no marine layer and skies will be totally sunny. Max temps will respond in kind and rise 5 to 10 degrees across the board. There will be some sub advisory 25 to 35 mph NE wind gusts in the morning.
On Thursday the first moderate to strong Santa Ana wind event will kick off. An upper level ridge will nose into nrn CA and this will set up NE flow aloft over Srn CA. At the sfc 4 mb of offshore flow will develop from both the E and N and will not subside much at all through the day. 850 mb winds from the NE will peak around 45 mph in the morning. This will combine with the sfc gradients to produce advisory level 40 to 50 mph gusts through the Santa Ana Wind Corridor (~10 miles either side of a line from Santa Clarita to Mugu NAS). Another 4 to 8 degrees of warming will bring upper 80s to lower 90 degree temps to all most all cst/vly locations. Unlike earlier heat events this warm up will be accompanied by single digit humidities typical of a Santa Ana Event.
The Santa Ana will peak on Friday. Offshore gradients will be near 7 mb from the east and 4 mb from the north. NE 850mb winds will range from 45 to 55 mph. Sfc winds will likely reach warning levels in many portions of the Santa Ana wind corridor with high end advisory level gusts across any area where warning level gusts (58+ mph) will not be reached. Downslope warming will bring 5 to 6 degrees of warming to the csts and 2 to 3 degrees for the valleys. Most areas will end up about 10 degrees over normal but the LA/VTA csts will be 15 to 18 degrees over normal.
(Sat-Tue), 14/226 AM.
The Santa Ana will wane on Saturday as both upper level and sfc support weaken. The winds will also take on more of an easterly direction and this will light up some canyons that were not that windy Friday. Max temps will fall 2 to 4 degrees but max temps will remain well above normal.
Look for three days of cooling Sunday through Tuesday. Sunday the offshore flow will reverse to the east while the offshore flow from the north will weaken. This will bring 3 to 6 degrees of cooling to the csts and vlys. The inland areas will not see much change.
Hgts will fall on Monday as a trof approaches the state. Onshore flow will develop to the north and the onshore push to the east will increase. These two items will combine to lower max temps by 3 to 6 degrees (6 to 8 across the Central Coast). Most of SLO/SBA counties will end up a little below normal while areas south of Pt Conception will still be a few degrees over normal.
A big cold upper low will rotate into and through the state Tue/Wed. It will probably be a dry passage, but there is about a 30 percent chc that it will find enough moisture to squeeze out a few showers. It will bring gusty westerly winds and 5 to 10 degrees of cooling.
14/1640z.
At 1609Z at KLAX, there was no marine layer nor inversion.
High confidence in CAVU TAFs.
KLAX, High confidence in CAVU TAF. Any east wind component will be AOB 7 kts 10Z-16Z.
KBUR, High confidence in CAVU TAF.
14/905 AM.
For the Outer Waters, moderate to high confidence in current forecast. For this afternoon through evening, a small craft advisory has been issued starting 6PM this evening till 3AM Thursday for PZZ673/676. For Thursday through Saturday, high confidence in winds and seas remaining below SCA levels for most of the waters. The only exception is there is a 20-30% chance of E-NE SCA level wind gusts across the outer waters south of the Channel Islands and west to northwest of San Nicholas Island due to Santa Ana winds during the late night through morning hours Thursday through Saturday. The highest chances are on Friday.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. There is a 30-40% chance of SCA level winds this afternoon and evening. Otherwise expect conds to remain below SCA levels.
For the Inner Waters south of Point Conception, moderate confidence in current forecast. High confidence in winds and seas remaining below SCA levels for most area through tonight, with the only exception is the western half of the Santa Barbara Channel where there is a 30% chance of SCA level winds this afternoon and evening. Thursday through Saturday, there is a 40-60% chance of SCA level northeast winds from Ventura south to Santa Monica and out past Anacapa Island and possibly from the Orange County Coast out to Catalina Island, strongest during the late night into early afternoon hours.
Long period swells from the west and the south are affecting the coastal waters, and can create a confused sea state. This can make boating more challenging and dangerous, especially for small vessels.
Ca, Wind Advisory in effect from 6 AM Thursday to 8 PM PDT Friday for zones 88-354-355-358-362-370>374-376-377. (See LAXNPWLOX). Heat Advisory in effect from 10 AM Thursday to 8 PM PDT Saturday for zones 340-341-346-347-349-350-354-355-362-366>368. (See LAXNPWLOX). Beach Hazards Statement in effect through Thursday afternoon for zones 354-362-366. (See LAXCFWLOX). High Wind Watch in effect from Thursday morning through Friday evening for zones 369-375-378>380. (See LAXNPWLOX). Red Flag Warning in effect from 6 AM Thursday to 10 PM PDT Friday for zones 288-354-355-358-362-369>380-548. (See LAXRFWLOX). Fire Weather Watch in effect from Friday morning through Friday afternoon for zones 345-353. (See LAXRFWLOX). PZ, Small Craft Advisory in effect from 6 PM this evening to 3 AM PDT Thursday for zones 673-676. (See LAXMWWLOX).
