13/206 PM.
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.
(Tue-Fri), 13/757 PM.
***UPDATE***
The brief cool period that brought an Autumn-like feeling to much of Southwest California will transition into our first Santa Ana Wind event of the season, so in some ways it will feel like Fall once again since this is quite typical in October. Some breezy winds will occur over the mountains tomorrow, but the most impactful portion of this event begins Thursday. A slew of headlines are in place with Red Flag Warnings, Fire Weather Watches, High Wind Watches, Wind Advisories, and Heat Advisories stretching across all four counties. We have high confidence in this moderate to strong event occuring.
As for today's weather, it was very quiet. Temperatures were a little warmer today versus yesterday, and skies were clear. Expecting another bump up in temperatures tomorrow, then the Santa Ana event will kick off Thursday.
***From Previous Discussion***
HIGH CONFIDENCE in a MODERATE TO STRONG SANTA ANA event peaking this Thursday and Friday with damaging wind, power outages and large fast moving fires possible in the region. HIGH WIND WATCHES, Wind Advisories and Red Flag Warnings cover the typical Santa Ana Wind Corridor in Los Angeles to Ventura County for 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 with highs up to 95 degrees. See weather.gov/lox to view individual product details.
Some actions to consider with the upcoming wind/heat/fire weather hazards:
Have a plan in place in the case of a power outage, especially if a wind or fire weather product is in effect in your area.
Secure loose outdoor items and be prepare for dangerous cross winds when driving, especially on elevated roadways.
In the event of a nearby wildfire, smoke may increase heat and physical stress. If smoke impacts your area; 1) Have a cooling plan in place as smoke could limit your ability to cool your home through open windows and 2) If you have air conditioning, set on air recirculation within the home to avoid smoke exposure. Local officials may have additional guidance.
Forecast details: The forecast through this weekend remains largely unchanged. A low pressure system is moving slowly through the Great Basin through Wednesday. That will set the stage for a developing Santa Ana wind event across portions of southern California this week as high pressure over the Great Basin forces winds up and over the mountains and down into the valleys and coastal areas. The rapid acceleration of the air into increasingly higher pressure at lower elevations will force the air to heat up significantly (per the gas law). Will start to see this process as early as today as the upper low advances to the southeast, allowing the transport of air from the north to begin. Latest models show just a very light north-northeast wind developing over the mountains today and tonight, then increasing in speeds each day through Friday, by which time winds aloft will be around 40-50 mph. In response, temperatures across the coast and valleys will warm by roughly 10 degrees each day, peaking Friday with highs in the upper 80s to mid 90s in most areas. Mountains and deserts will warm as well but by much lower amounts.
The Santa Ana winds will be strongest for most areas Friday but Thursday likely a close second within the Santa Wind Corridor of Los Angeles to Ventura Counties. We could see wind gusts into the 60s and 70s in the most favored exposed areas of the San Gabriel Mountains. Widespread peak gusts of 35-55 mph are expected within the Wind Advisory. Gusty east winds of 30-40 mph may expand into interior Santa Barbara and San Luis Obispo mountains into Friday and is covered by the Fire Weather Watch.
(Sat-Tue), 13/206 PM.
One more day of gusty Santa Ana winds are possible (30-40 percent chance of reaching advisory levels) into Saturday, taking on a more easterly orientation.
Temperatures are expected to remain well above normal through Sunday, but rapidly cool into early next week. And looking out a little further there is fairly high agreement in the models that another cold upper low will move into the area the middle of next week, for another big swing into temperatures and weather conditions. It looks like mainly a dry system at this point, but there is a 30-40 percent chance that it tracks just enough offshore to support some shower activity. The much cooler weather will arrive on gusty northwest to west winds focused in the Tuesday/Wednesday window.
13/2317z.
At 1736Z at KLAX, there was no marine layer nor inversion.
High confidence in VFR TAFs for all sites.
KLAX, High confidence in TAF. Light easterly wind component expected to remain below 7 kts in the morning hours.
KBUR, High confidence in TAF. No wind issues expected.
13/757 PM.
For the Outer Waters, moderate to high confidence in current forecast. For the afternoon and evening periods through Wednesday, there is a 50-70% chance of SCA level winds across the Outer Waters, especially around Point Conception. 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. Through Wednesday, there is a 30-40% chance of SCA level winds in the afternoon and evening hours. Otherwise expect conds to remain below SCA levels.
For the Inner Waters south of Point Conception, moderate confidence in current forecast. Through Wednesday, high confidence in winds and seas remaining below SCA levels for most area, but the only exception is the western half of the Santa Barbara Channel where there is a 50% 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 until 9 PM PDT this evening for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until midnight PDT tonight for zones 670-673-676. (See LAXMWWLOX).
