11/459 PM.
A significant cooling trend will begin Thursday, with temperatures falling to near normal by Friday. Off and on rain is expected Thursday night into early Saturday and more storms are possible next week.
(tdy-Sat), 12/937 AM.
***UPDATE***
Big cooling today as this week long offshore pattern finally swings onshore. Highs today expected to be 5-10 degrees cooler than yesterday.
Our next weather system is rapidly approaching. Dry during the daytime hours but increasing rain chances after 10pm in southern Santa Barbara County and after midnight in LA County. There are some convective elements to this but best chances for any thunderstorms would be south of LA County. Rain rates will mostly be under a quarter inch per hour but high res models still showing around a 20-30 percent chance rates as high as a half inch per hour.
Scattered showers expected during the day Friday, more so in the morning and mostly south of Pt Conception.
***From Previous Discussion***
The second shot of precipitation, associated with a frontal passage, will impact the area late Friday afternoon/evening into Saturday morning. This will bring a good chance of more widespread rainfall to the area. At this time, rainfall totals with this second impulse look to be in the 0.25-0.75 inch range with locally higher amounts possible across more favored mountain slopes.
Between the two impulses, rainfall totals are expected to top out in the 0.25-1.00 inch range for most areas with locally higher amounts possible across some mountain slopes and associated with any thunderstorm activity. Rainfall rates are expected to mostly be 0.25 inches/hour or less although local rates around 0.50 inches/hour will be possible.
Other than the rain chances, this pattern will bring noticeably cooler conditions to the area on Friday/Saturday with high temperatures topping out in the 60s to lower 70s. Additionally, there will gusty southwest to northwest winds Friday and Friday night with a chance of some low end advisory-level winds across interior sections.
(Sun-Wed), 12/118 AM.
For the extended, models continue to exhibit decent synoptic agreement. Pattern-wise, the "storm train" is expected to continue with one storm impacting the area Sunday night through Tuesday then another system during the day on Wednesday/Wednesday night.
At this time, the ECMWF is more bullish with rain totals than the GFS. Based on current QPF guidance, the Sunday night-Tuesday system will likely generate 0.10-0.50 inches and the Wednesday and Wednesday night storm will likely generate 0.25-1.00 inches. Of course, given this is in the extended period, these expected totals will likely change from day-to-day. Looking at the respective ensembles, there is a 10-20% chance of totals being higher than the current forecast.
Other than the rain chances, partly to mostly cloudy conditions will be likely through the extended period. High temperatures will be cooler, generally in the 60s with temperatures in the 40s and 50s across the mountains.
12/1907z.
At 1732Z at KLAX, the marine inversion was 1700 feet. The top of the inversion was 2300 feet with a temperature of 18 degrees Celsius.
Moderate to high confidence in TAFs due to the potential for off and on MVFR cigs through this evening, especially for Ventura County and northward. Gusty southerly winds will impact Central Coast sites through this afternoon, then weak southerly winds may occur overnight at any site. -SHRA will likely impact most sites overnight into Friday morning, but timing may be off +/- 3 hours.
KLAX, High confidence in TAF. 15% chance for brief MVFR cigs 015-030 through this evening. Timing of -SHRA +/- 3 hours. Any east wind is likely to remain less than 8 knots. 10% chance of -TSRA overnight.
KBUR, High confidence in . Through this evening, CAVU conditions are expected. Overnight, VFR CIGs are expected with a chance of light showers. 5% chance of -TSRA overnight.
12/803 AM.
For the Outer Waters, high confidence in current forecast. Today through Tuesday, a combination of Small Craft Advisory (SCA) level winds and seas is expected. Winds look to peak on Friday and Saturday, then again on Monday. Dangerously large seas are expected to peak on Saturday (15-22 feet) with a secondary peak expected on Monday (12-18 feet).
For the Inner Waters north of Point Sal, high confidence in current forecast. Tonight through Tuesday, a combination of SCA level winds and seas are expected. Winds look to peak on Friday, then again on Monday. Dangerously large seas are expected to peak on Saturday (14-19 feet) with a secondary peak on Monday (11-15 feet).
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For today, high confidence in winds and seas remaining below SCA levels. For Friday through Saturday, there is a 40-50% chance of SCA level winds. On Sunday, high confidence in winds and seas remaining below SCA levels. On Monday, there is a 60-80% chance of SCA level winds.
With the expected large westerly swell this weekend, there is the threat of dangerous breaking waves at Ventura and Morro Bay harbor entrances.
Today through Monday, there will be the threat of showers, especially Friday/Saturday then again on Monday. Also, there will be a slight chance of thunderstorms south of Point Conception late tonight and Friday.
12/824 AM.
A series of very large, long period west-northwesterly swells will impact the coastline of southwest California through at least Tuesday of next week, creating large surf.
Largest surf will be focused along west to northwest facing shores and surf is expected to peak on Saturday. Significant beach erosion and shallow flooding of sea water over low-lying beach walkways, parking lots, and roads is likely, especially in the morning hours near high tide. Large surf will create dangerous rip currents, along with strong long shore currents, potential sneaker waves and large shore pound. Impacts will be less for south-facing shores.
The highest risk will be for the Central Coast with potential for localized damage to the most vulnerable areas - such as to piers, roads, and structures. A coastal flood watch has been issued to highlight the potential for WARNING-level inundation, such as widespread flooding at Oceano Dunes State Park. There is a HIGH chance for WARNING-level Surf which current guidance shows potential for 18-25 ft across northwest facing shores.
For west-facing beaches in LA/Ventura counties, there is a high chance for advisory level surf as soon as this afternoon and continuing into Tuesday of next week, with brief relative lulls possible at times. There is a low chance for WARNING-level surf for Ventura County beaches on Saturday.
Ca, Beach Hazards Statement in effect through Tuesday afternoon for zones 87-349-350. (See LAXCFWLOX). High Surf Advisory in effect until 9 PM PST Friday for zones 340-346. (See LAXCFWLOX). High Surf Warning in effect from 9 PM Friday to 3 AM PST Sunday for zones 340-346. (See LAXCFWLOX). Coastal Flood Warning in effect from 3 AM to 6 PM PST Saturday for zones 340-346. (See LAXCFWLOX). Beach Hazards Statement in effect until 2 PM PST this afternoon for zone 354. (See LAXCFWLOX). High Surf Advisory in effect until 3 PM PST Tuesday for zone 354. (See LAXCFWLOX). Beach Hazards Statement in effect through Friday afternoon for zones 362-366. (See LAXCFWLOX). High Surf Advisory in effect from 2 PM Friday to 3 PM PST Tuesday for zones 362-366. (See LAXCFWLOX). PZ, Small Craft Advisory in effect from 3 AM Friday to 3 AM PST Wednesday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Wednesday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PST Wednesday for zone 673. (See LAXMWWLOX). Small Craft Advisory in effect from 6 PM this evening to 3 AM PST Wednesday for zone 676. (See LAXMWWLOX).
