02/830 PM.
A moderate Santa Ana wind Event will impact SoCal Wednesday morning through Thursday. Cold overnight low temperatures will occur through the work week, coldest Wednesday night into Thursday morning away from the coasts. A significant warming trend will begin this weekend and will approach 5-10 degrees above normal in most areas. Highs will peak sometime next week at 10-15 degrees above normal.
(Tue-Fri), 02/828 PM.
***UPDATE***
High clouds and currently blocking our view of any low cloud development, but based on some other observations, there are some unorganized smatterings of low clouds. The HREF wants to develop those later tonight over Los Angeles and Ventura Counties, but with offshore flow developing it will be very hard to predict. Concerning that offshore flow, it is still on target to impact the area Wednesday and Thursday. The current Wind Advisory looks good for later Wednesday Night through Thursday, but really unsure just how strong it will be during the day on Wednesday and how far down to the coast it will blow. Will likely need some more Freeze Warnings and Frost Advisories for Thursday and Friday mornings, but will let future shifts sort that out. The rest of the forecast looks on track.
***From Previous Discussion***
After a relatively mild weather day today, Santa Ana Winds will return Wednesday morning, continuing through Thursday. This is shaping up to be a moderate wind event with 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.
Wind Advisories have been issued across the typical Santa Ana Wind corridor for Wednesday morning through Thursday afternoon. There is a chance that coastal and valley winds will struggle to develop in the early morning hours, so the onset may be delayed until later in the morning. Relative lulls in the winds are also possible in the later afternoon and evening hours Wednesday. There is a chance that Wind Advisories will need to be extended across the mountain areas into late Thursday as the winds will turn slightly more northerly. While winds are not forecast to be widespread at damaging speeds, there is still a small chance for trees to come down more easily due to wet soils from the November rainfall. Winds may also knock down or blow away outdoor holiday decorations, so be sure to secure those decorations or keep them sheltered from the winds. While some Santa Ana Wind events will produce very warm temperatures, this is not one of them. Highs will increase slightly and highs in the upper 60’s to low 70’s will be common.
In addition to the incoming Santa Ana winds, some fairly cold overnight temperatures will be common across much of the interior portion of the region as the offshore flow limits marine air influence. Freeze Warnings have been issued for the southern Salinas Valley as well as the interior SLO County Valleys. Although low temperatures will be near freezing for portions of the Antelope Valley, a Freeze Warning was NOT issued as overnight lows are forecast to be slightly warmer than last night’s freeze. Wednesday night into Thursday morning will likely be the coldest night of the season so far. Low temperatures in the 20’s and 30’s will be common across most areas away from the coasts, while coastal and coastal valley areas will bottom out in the 40’s to low 50’s. Widespread Frost/Freeze products are likely for this time period.
Temps will begin to steadily climb Friday as upper level ridging takes over the West Coast. Weak onshore flow to the east will develop Friday and Saturday in the afternoon, but northerly gradients will remain offshore. If post Santa Ana wind fog is able to form, it’ll likely be confined to the coast (and coastal waters) and be dense.
(Sat-Tue), 02/202 PM.
The Pacific (and persistent) Ridge will continue to build into the region over the weekend, parking itself and becoming more robust early next week, with 500 mb heights approaching the 95th percentile climatologically. It’ll be quite a warm stretch as all indications are that this ridge will continue through the end of next week. Widespread temps in the 70’s and potentially the low 80’s will be common come Sunday or Monday. Both the EC and GFS indicate weak to moderate offshore flow from the north and east early next week.
03/0222z.
At 2350Z at KLAX, there was no marine layer, and no inversion.
Moderate to high confidence in TAFs for KPRB, KSBP, KSMX, and KSBA, KWJF, and KPMD. At KPRB, KSMX, and KSBA there is a 10 percent chance of IFR-MVFR cigs from 13-16Z Wed.
Low to moderate confidence for KOXR, KCMA, KSMO, KLAX, KLGB, KBUR, and KVNY. Arrival of any cigs may be off by 2-3 hours from forecast and may be off by 1 category at times. There is also a 10-20% chance that no cigs form at sites where they are forecasted. Short-lived IFR- MVFR conditions are possible (20% chance) between 12Z-16Z Wed at KBUR and KVNY, and there is a 10% chance of brief dense fog (V/LIFR) conditions across the LA Basin from 13Z-16Z Wed.
KLAX, Moderate confidence in TAF, cigs may for between BKN008-BKN025, with a 20 percent chance of VFR conditions through the period. East winds are possible from 10Z Wed to 20Z Wed, with a 30-40% chance of the east wind component exceeding 6-8kt. Best chance for stronger east winds is around 13Z to 17Z.
KBUR, Moderate confidence in TAF, there is a 20% chance of BKN008-BKN025 cigs between 12Z-17Z Wed.
02/942 PM.
For the outer waters, moderate to low confidence in the current forecast. The NW swell came in somewhat lower than expected, therefore Small Craft Advisories were canceled for the outer waters south of Point Sal. Some localized winds may gust near SCA levels at times tonight, but should be short-lived. Then winds and seas should mostly remain below Small Craft Advisory (SCA) levels Thursday through Saturday, with winds increasing to near SCA levels at times, mainly Friday night and Saturday night.
For the nearshore waters, easterly winds are expected to develop from the Ventura County Coast into the Santa Barbara Channel late morning to early Wednesday afternoon. Localized gusts near SCA levels will be possible through the afternoon hours. Then there is a 40 to 50 percent chance of SCA level winds with short- period seas developing late Wednesday night into Thursday morning. Northeast Santa Ana wind will be the strongest near the coastline between Ventura Harbor and Santa Monica. Late Thursday through Saturday, winds and seas are expected to generally remain below SCA levels.
Ca, Wind Advisory remains in effect from 6 AM Wednesday to 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 remains in effect from 1 AM to 8 AM PST Wednesday for zones 343-344. (See LAXNPWLOX). Beach Hazards Statement in effect through Saturday morning for zones 349-350-362-366. (See LAXCFWLOX). High Surf Advisory in effect until noon PST Thursday for zone 354. (See LAXCFWLOX). Coastal Flood Advisory in effect from 3 AM to 10 AM PST Wednesday for zone 354. (See LAXCFWLOX). Frost Advisory in effect from 1 AM to 8 AM PST Wednesday for zone 357. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 10 AM PST Wednesday for zone 670. (See LAXMWWLOX).
