.SHORT TERM (WED-SAT)...11/804 PM.

***UPDATE***

Current forecast on track in the short term. Gusty winds continued along the SBA County Central Coast, SW SBA County coast and mtns, VTU County mtns to the I-5 Corridor in NW L.A. County, and the Antelope Vly and foothills, especially on the west side. Gusts up to 60 mph are expected over the SW SBA County coast and mtns, especially through and below the passes and canyons. A High Wind Warning continues for this area until later Thu morning. The other aforementioned areas are under Wind Advisories until late Thu morning due to gusts of 35-55 mph, strongest in the higher terrain. Please see the latest Non-Precipitation Weather Message (LAXNPWLOX) for further details.

The marine inversion has deepened to about 1600 ft at VBG early this evening, while at LAX it was running about 1000 ft or so. Low clouds have moved into portions of the Central Coast early this evening and will expand further overnight and into the Santa Ynez Vly. S of Point Conception, low clouds which were E of Catalina Island are also expected to expand to the L.A. County coast overnight and northward to the VTU County coast by daybreak. Low clouds are also expected to develop over the SLO County interior vlys overnight. Elsewhere and otherwise, mostly clear skies will prevail thru the night.

***From Previous Discussion***

Satellite loops show a large upper trough amplifying off the British Columbia coast to the Pacific Northwest. For the remainder of this week, the trough will further deepen and slide southeastward and then eastward, sending cooler air across the local area. LAX-DAG pressure gradients have increased by another 3 mb over the past 24 hours, signaling the strengthening onshore flow, with early-afternoon temperatures down 10-20 degrees from where they were 24 hours ago. By Thursday, high temperatures in the 70s and 80s will be common region-wide, except a little cooler at the beaches. Only a slight rebound in temperatures comes on Friday and Saturday as the upper trough moves farther away from the area.

The mass response to synoptic troughing will continue to bring about an increase in winds over the high terrain. Wind Advisories have gone into effect for gusty west to north winds across the Interstate-5 Corridor, Antelope Valley and adjacent western foothills, as well as the Ventura County Mountains and Santa Barbara County Interior Mountains. Gusts of 45-55 mph will be common in these areas during the Wind Advisory in effect until late Thursday morning. Local gusts to 60 mph will be possible in the most wind-prone areas through canyons and passes. For the southwest Santa Barbara County coast and western Santa Ynez Range, the combined influences of a strong coastal jet, offshore pressure gradients for SBA-SMX and SBA-BFL up to 3-4.5 mb, and some upper support have increased confidence in gusts reaching 60 mph warranting issuance of a High Wind Warning. Onshore wind gusts to 35 mph also warrant Wind Advisories for the Santa Barbara County Central Coast Beaches. Expect winds to be decreasing later in the day on Thursday and into Friday as pressure gradients weaken, though weak Sundowners should persist late this week.

The marine layer will continue to advance inland to the south of Point Conception through Thursday in response to the strengthening onshore flow and falling midlevel heights. By Thursday, marine- layer depth and areal coverage will maximize, facilitating more widespread stratus and night through morning fog extending through coastal valleys and toward the foothills. Some patchy drizzle could occur during that time-frame, as well. Then by Friday, pressure gradients trend offshore owing to the eastward progression of the surface ridge well north of the forecast area.
This will lead to a faster clearing trend following any overnight marine stratus or fog. Otherwise, dry conditions are expected through the end of this week. The marine layer will begin to more prominently return once again by Saturday while pressure gradients trend onshore ahead of the next reinforcing trough.

In addition, smoke is included in the forecast in northeastern LA County, in association with ongoing wildfires.

.LONG TERM (SUN-WED)...11/217 PM.

High-amplitude troughing will predominate over the western states for the remainder of this weekend and into next week, bringing an extended period of cooler-than-normal temperatures. While high temperatures will be in the 70s and 80s in most areas through late weekend, temperatures for next week should fall by at least another 5 or 10 degrees -- as an unseasonably strong and large vorticity maximum envelops much of the western CONUS. While there are some differences among model solutions regarding the exact geometry and depth of this feature, there is growing confidence in this much more significant cool-down occuring early next week.
Moreover, there is a 20-40% chance for high temperatures to be several degrees cooler than current Monday through Wednesday projections, and afternoon temperatures might not rise much above 70 degrees in many areas -- if the core of the upper low ends up deeper or displaced farther south.

With the stronger flow fields surrounding the strong upper disturbance, gusty winds over the high terrain and Antelope Valley will be a concern especially late this weekend and into early next week. There is a 30% chance for wind headlines to become necessary between Sunday and Monday.

The quick return to reinforced upper troughing and strengthening onshore flow will foster deepening of the marine layer through late this weekend. As a result, marine stratus and night through morning fog will quickly return and may be somewhat slow to recede each day by Sunday. By Sunday night into Monday, significant deepening of the marine layer will yield increasing chances for drizzle. Also, there will be a 20-30% chance for light rain showers to affect the region Sunday night into Monday as the strongest forcing for ascent ahead of the upper vorticity maximum crosses the region, and midlevel temperatures cool serving to destabilize the troposphere. The eventual position and depth of this disturbance will greatly influence the evolution of marine stratus and fog, which could completely clear out by next Tuesday or Wednesday due to the erosion of the inversion surmounting the marine layer from cooling aloft.

AVIATION
12/0618Z.

Around 0515Z, the marine layer depth was around 1600 feet deep at KLAX. The top of the inversion was near 2800 feet with a temperature around 21 degrees Celsius.

Low-to-moderate confidence in the forecast for coastal and valley terminals forecast, otherwise high confidence in the forecast for desert terminals. Higher confidence exists in flight categories.
Less confidence exists in timing.

IFR to MVFR conditions are likely across coastal and valley terminals through at least 15Z. There is a moderate chance of LIFR conditions at Central Coast terminals between 10Z and 16Z.
VFR conditions should develop between 16Z and 18Z. For desert terminals, VFR conditions are likely to persist.

KLAX...There is a 70 percent chance of MVFR conditions. MVFR conditions could push into KLAX as soon as 09Z, or as late as 12Z.
VFR conditions should develop between 17Z and 18Z, but there is a 30 percent chance of VFR conditions holding off until as late as 20Z. Any easterly winds should be less than 7 knots.

KBUR...There is a 60 percent chance of IFR to MVFR conditions. IFR to MVFR conditions could arrive as soon as 11Z, or as late as 14Z. VFR conditions should develop between 15Z and 17Z. No wind impacts are expected at this time.

MARINE
11/1009 PM.

For the Outer Waters from the Central Coast to San Nicolas Island, wind gusts have been close to or briefly hitting gale force. Will be keeping the current Gale Warning in effect thru at Thurs morning, however it may need to be expired early. Leaning towards not extending the Gale Warning through Thursday night as current guidance suggests winds will be weaker than tonight (max gusts of 30-32 kt possible). Expecting strong Small Craft Advisory (SCA) level winds Thursday evening, lasting into Friday morning, with a 20-30% chance they persist thru Friday night. SCA level winds are not expected Sat morning thru evening, but high confidence in winds picking back up to SCA level by as early as late Sat night and persisting thru at least the weekend. Seas will be steep and choppy thru at least Friday.

For the nearshore waters off the Central Coast, moderate confidence in the forecast. There is a 30 percent chance that winds will come in just under Gale Force thru late tonight, or be limited to the western edge of the zone (10 NM out). Winds will subside but likely (70% chance) remain above SCA level thru late Thur. Then winds should remain below SCA level thru most of the weekend. However, moderate confidence in winds increasing to SCA level Sunday in the afternoon thru evening hours. Steep and choppy seas are expected through Friday.

For the Santa Barbara Channel, moderate confidence in the forecast. Winds are will be strongest in the western and southern portions of the channel (SCA levels or near) for tonight.
Moderate confidence in SCA level winds occuring tomorrow in the afternoon thru evening hours in the same area. Moderate to high confidence in winds remaining below SCA level thru Sunday morning, with a 20-30% chance of SCA level winds in the afternoon thru evening hours Sunday. Seas will be to be choppy through Friday morning.

For the inner waters off the Los Angeles/Orange County coasts, moderate to high confidence in forecast. There is a 20-30% chance of SCA level winds during the afternoon and evening hours tomorrow, with the best chance across the western and far northern portion. Seas are likely to be choppy through Thursday.
Otherwise, conds are expected to remain below SCA levels through the weekend.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory remains in effect until 11 AM PDT Thursday for zones 346-353-376>378-381-383. (See LAXNPWLOX).
High Wind Warning remains in effect until 11 AM PDT Thursday for zones 349-351. (See LAXNPWLOX).
Red Flag Warning in effect until 10 AM PDT Thursday for zones 380-382. (See LAXRFWLOX).
PZ...Gale Warning in effect until 3 AM PDT Thursday for zone 645. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PDT Thursday for zone 650. (See LAXMWWLOX).
Gale Warning in effect until 9 AM PDT Thursday for zone 670. (See LAXMWWLOX).
Gale Warning in effect until 11 AM PDT Thursday for zones 673-676. (See LAXMWWLOX).