12/541 PM.
Near normal temperatures are expected on Sunday, followed by below normal temperatures through at least Wednesday. Low clouds will affect coastal areas during the night to morning periods, along with gusty onshore winds each afternoon. Warming is likely to return towards the end of this coming week.
(Sat-Tue), 12/810 PM.
***UPDATE***
Gradual cooling has affected the region over the past couple of days, with max temperatures near to slightly above normal today. Highs along the coast were in the 70s to lower 80s, with mid 80s to mid 90s over the interior. Additional slight cooling is expected tomorrow, lowering to near or slightly below normal. The most significant temperatures drops are likely to occur over the far interior, lowering around 6 to 10 degrees below today's highs.
Gusty winds are affecting portions of the area, including NW to N Sundowners over the western Santa Barbara South Coast where gusts are increasing to over 40 mph at of 700 PM. Wind Advisories are in effect for the whole South Coast and adjacent Santa Ynez Foothills through 6 AM Monday. Across the eastern sections where north to northeast winds are expected, speeds may be slower to rise to advisory levels. KSBA to KBFL gradients are forecast to increase further Sunday night compared to tonight. Gusty northerly winds will affect other areas north of Point Conception, including the Central Coast south of Morro Bay and the Santa Lucias. Northerly winds will also increase through the Grapevine, possibly reaching Advisory levels Sunday night.
Breezy onshore winds are affecting interior areas as well, such as the passes and canyons into the Antelope Valley and interior SLO County, and are expected to occur each afternoon to evening period.
Night to morning low clouds and fog will mainly affect coastal areas thanks to light offshore flow over the next several days.
***From Previous Discussion***
A relatively quiet stretch of weather will continue over the next several days across southwestern California. Areas south of Point Conception will see cooling through Wednesday, with highs generally cooler than mid-September averages, especially Monday- Wednesday. The combination of light offshore flow in the overnight through morning period and limited marine layer cloud cover (thanks to the offshore flow) will result in slight warming over the Central Coast Sunday and Monday, with a cooling trend taking the reigns Tuesday-Wednesday. More noticeable will be the much less muggy feeling weather at atmospheric mositure is much lower than last week, and will continue to decrease through tonight.
Breezy onshore winds will be common each afternoon, with some gusty northwest to northeast winds across some interior and even some coastal mountains (eastern Santa Ynez/Santa Lucias), with a low to moderate chance for wind advisories to be needed for Sunday night in windiest areas, such as the Grapevine area. Additionally, gusty Sundowner winds will impact southern Santa Barbara County through Monday morning, and a Wind Advisory is in place.
Night through morning marine layer clouds will be common at times, however offshore flow will limit marine keep clouds along the Central Coast the next couple of nights. Sundowner winds will likely keep marine layer clouds away from the Santa Barbara south coast and potentially Ventura County.
(Wed-Sat), 12/1243 PM.
Little change expected Tuesday-Wednesday with a fairly stagnant upper pattern and persistent moderate to strong onshore flow. There may be slight cooling each day, but the fairly mild mid- September should continue. The marine layer will likely become more robust across all coasts and maybe some lower valleys.
The consensus in models for Thursday through the end of next week is for warming, as high pressure builds in from the southeast and onshore flow weakens. The magnitude of that building high pressure and the offshore trends are still to be settled, which means the magnitude of the warming is uncertain. Temperatures pushing above normal look very likely, with a low but non-zero chance of Heat Hazard-level hotness. Peering down to the south, there are a couple of tropical systems that could provide some moisture, but the signal is weak at this point.
13/0049z.
At 2351Z at KLAX, the marine layer was 1400 feet deep. The top of the inversion was at 3400 feet with a temperature of 24 degrees Celsius.
For the 00Z TAF package, high confidence in CAVU conditions for KPRB, KSBA, KWJF and KPMD.
For all other sites, low to moderate confidence due to uncertainties in marine layer cloud coverage overnight. There is a 40% chance of MVFR/IFR conditions at KSBP, KOXR and KCMA 08Z-15Z. For KBUR and KVNY there is a 30-40% chance that no CIGs occur, or that CIGs appear briefly or intermittently. For the LA Basin TAFs, timing of flight category changes could be +/- 3 hours of current forecasts.
KLAX, Low to moderate confidence in the 00Z TAF. The timing of MVFR conditions could be +/- 3 hours of current forecast of 09Z-17Z. CIGs could be brief or intermittent. No significant easterly wind component is expected.
KBUR, Low confidence in the 00Z TAF. The timing of CIG/VSBY restrictions could be +/- 3 hours of current 09Z-16Z forecast. There is a 30-40% chance that no CIGs occur.
12/639 PM.
High confidence in current suite of Small Craft Advisories (SCA) and Gale Warnings (GLW). Gale Force winds are expected for all outer waters through Sunday night, with Sunday afternoon and evening likely the strongest. Gale conditions may linger into Monday morning, with moderate confidence that SCA winds will linger into late Monday night or early Tuesday morning. Strong SCA winds will reach into the nearshore waters along the Central coast and Santa Barbara Channel through the weekend. These winds will generate a building short-period fresh swell over all waters, peaking in the afternoon & evening hours.
Ca, Wind Advisory in effect until 6 AM PDT Monday for zones 349-351-352. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 11 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Sunday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PDT this evening for zones 670-673-676. (See LAXMWWLOX). Gale Warning in effect until 6 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).
