03/801 PM.
A moderate Santa Ana wind event will bring gusty northeast winds to portions of southern California through Thursday. Cold conditions will bring freezing conditions to some areas each morning through Friday. A significant warming trend will begin this weekend and peak next Tuesday and Wednesday.
(Wed-Sat), 03/803 PM.
***UPDATE***
Not a whole lot to write about that is not already mentioned below. The forecast is in good shape. The offshore winds are following their typical diurnal trends, becoming more confined to the mountains and hills, but will strengthen and expand later tonight and peak in coverage and strength later Thursday morning. All the Frost and Freeze hazards look on track.
***From Previous Discussion***
This round of Santa Ana winds has been slow to develop, especially across more populated valleys and coasts as coastal marine influences have been battling the drier airmass. Advisory level gusts have begun to be observed across the San Gabriels and Santa Susanas, but coasts and coastal valleys have generally been below 35 mph, although winds have been ticking up in the last couple of hours. A relative lull will occur this afternoon through evening. But confidence is high in stronger and more widespread Santa Ana Winds returning late tonight and continuing into Thursday afternoon, with the peak being Thursday morning. We are expecting winds in the 25-35 mph range across the valleys and coasts, while favored foothills may gust to 45 mph at times. Across the San Gabriels, Santa Susanas, I-5 Corridor, and portions of the southern Ventura County mountains, winds will be common in the 35-45 mph range with gusts to 55 mph. Isolated gusts to 60 mph are possible in the mountains, especially the Western San Gabriels and the Santa Susanas. The current Wind Advisory will remain in place and no locations have been added. Although it has been dry for a couple weeks now, soils may still be wet below the surface, which could lead to trees being downed more easily. Don’t forget to secure those outdoor decorations and objects! Winds will weaken some and even turn onshore Friday and Saturday afternoon.
Tonight will feature quite cold temperatures region-wide for areas absent of Santa Ana Wind influences. Freeze Warnings have been issued for the Antelope Valley, southern Salinas Valley, and interior San Luis Obispo County valleys. Frost Advisories have been issued for the Antelope Valley Foothills (isolated temps below freezing possible), Ojai Valley, and Cuyama Valley. Widespread low temperatures tonight will be in the mid 20’s to mid 30’s, coldest in the areas with Freeze Warnings in place. Elsewhere, overnight lows will be in the 40’s and 50’s as the downsloping winds will play a part in keeping overnight lows elevated. For the Los Angeles Basin, temperatures will be in the 40s, with a very low (less than 10%) chance for overnight lows briefly dipping below 40 degrees in the downtown area. Overnight lows will tick up a few degrees each of the next couple nights.
As far as high temperatures go, the upper level weak troughing will be nudged to the east by the incoming Pacific Ridge. Highs will slowly climb into the 70’s for much of the area by Friday, save for interior portions and immediate coasts. The ridge will slowly move overhead over the weekend, fostering quite warm temperatures for this time of year over the weekend especially across the interior on Sunday. The immediate coasts will likely remain in the 60’s as the onshore flow kicks in Friday and Saturday.
(Sun-Wed), 03/211 PM.
The main focus in the long term will be the high temperatures. The Pacific Ridge moving overhead will be responsible for keeping us locked into a prolonged warm and dry period. By Sunday, 500 mb heights will reach the 90-95th percentile compared to climatology, and the ridge will park itself along the California Coast through most of the week. Monday through Wednesday looks the warmest, and 500 mb heights will likely exceed the 95th percentile during this period. Temperatures will start cooling next Thursday and Friday but still well above normal.
There will be some northerly flow developing Sunday night through Tuesday that will bring dry and gusty winds to north exposed areas which includes most of the mountains as well as southern Santa Barbara County.
04/0603z.
At 0510Z at KLAX, there was no marine layer. There was a sfc based inversion with a top of 1000 ft and temperature of 16C.
High confidence in cig/vis fcst. Moderate confidence in wind fcst for KOXR, KCMA, KVNY, KPMD, and KWJF. Wind direction may be off by +/- 30 degrees and speeds by 5-10 kts.
lgt-ocnl mdt turbulence is possible over and near to higher terrain.
KLAX, High confidence in cig/vis fcst. There is a 30% chance of a 6-8 east wind component 09Z-19Z.
KBUR, High confidence in TAF. Ocnl LLWS is possible after 09Z-19Z.
03/928 PM.
Northeast offshore winds will impact portion of the coastal waters south of Santa Barbara County tonight through Thursday morning. The strongest winds will be nearshore from Ventura Harbor south to Santa Monica and across the San Pedro Channel off the coast of Orange County. Winds 15 to 25 kt with local gusts up to 35 kt will be possible. There is a 60 percent chance of east wind gusts 15-25 kt occuring across east-facing harbors on Catalina Island Thursday morning.
Friday afternoon through Monday, Small Craft Advisory (SCA) winds are possible (40-60% chance) across the outer waters, with the greatest chances in the afternoon and evenings north of the Channel Islands. Seas may exceed 10 feet across the aforementioned area over the weekend. Otherwise and elsewhere, mild conditions are expected Thursday through at least the weekend.
Ca, Frost Advisory in effect until 8 AM PST Thursday for zones 38-357-381-382. (See LAXNPWLOX). Beach Hazards Statement in effect through Saturday morning for zones 87-349-350-362-366. (See LAXCFWLOX). Wind Advisory remains in effect until 3 PM PST Thursday for zones 88-354-355-358-362-369>371-374>376-378>380. (See LAXNPWLOX). High Surf Advisory in effect until 3 AM PST Thursday for zones 340-346. (See LAXCFWLOX). Freeze Warning in effect until 8 AM PST Thursday for zones 343-344-383. (See LAXNPWLOX). High Surf Advisory in effect until noon PST Thursday for zone 354. (See LAXCFWLOX). PZ, Small Craft Advisory in effect from 6 AM to 2 PM PST Thursday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 2 PM PST Thursday for zones 655-676. (See LAXMWWLOX).
