12/449 PM.
Minor to moderate coastal flooding is likely continue through at least Tuesday. Beginning Tuesday, moderate to strong offshore flow will bring warm and dry conditions to the area through late in the week.
(Mon-Thu), 12/821 PM.
Current satellite imagery showing some residual low level moisture and associated clouds across the interior, otherwise mostly clear skies. Any rain chances have ended this evening across the area, and we will be noticeably cooler tonight in most areas, especially the interior where lows in the 40s will be common. A slight offshore wind component will begin to develop across the interior on Tuesday, and that will lead to mostly sunny skies and some warming. Further warming and drying will occur as an uptick in offshore winds develop across the mountains and valleys of LA/Ventura counties. At this point, thinking most areas will remain below wind advisory thresholds on Wednesday, but the LA county mountains will be close with gusts up to 40 mph likely. LAX-Daggett pressure gradient peaks at -3 mb on Wednesday morning. This will be enough offshore wind to bring another bump up in temperatures on Wednesday, with most areas climbing into the mid 70s to mid 80s. This will likely set the drying stage before our first widespread Santa Ana event that will likely peak Thursday into Friday, bringing a return of fire weather concerns to the region.
*** From previous discussion ***
A highly amplified upper level pattern has developed over the eastern Pacific and it appears southwest California will be experiencing quite a range of temperatures and weather conditions over the next couple of weeks. The upper low over the area yesterday and today that has brought scattered light showers and much cooler temperatures will evolve into our first real Santa Ana wind event of the season later in the week. For today though, highs will mostly be in the 60s which is 10-20 degrees below with some off and on light showers, mainly in the morning.
As the upper low slowly moves into the Great Basin, onshore pressure gradients will be weakening and a light northeast flow aloft will develop over the area as early as Tuesday afternoon. Not expecting any winds of significance Tuesday but high temperatures will warm up 4-8 degrees area-wide as the air mass dries out and heights rise at least 10dam.
Wednesday will be noticeably warmer and drier as offshore gradients continue to increase across the area heights climb another 10dam. Still not expecting any significant winds yet except possibly some northeast winds in the San Gabriel mountains up to 40 mph.
Santa Ana winds will really pick up Thursday into Friday as all the ingredients appear be in place and properly aligned. We have above normal confidence in moderate to strong Santa Ana winds during this timeframe. The latest ensemble pressure gradients indicate that the peak offshore gradient will occur Friday morning somewhere in the 5-7 mb range. Couple that with 50kt winds at 850 mb and very strong upper level subsidence, that should result in peak winds of 50-70 mph in the San Gabriel mountains and 35-55mph across the LA/Ventura valleys as well as the Ventura County coastal areas and Santa Monica mountains. This will likely be a hot and dry Santa Ana, so large and fast moving fires are a concern heading into this time frame. As a reminder, Santa Ana winds typically do not impact the LA Metro area and LA coast.
Temperatures will be peaking during these days as well with highs in the upper 80s and 90s across all coast and valleys, including the Central Coast. There is a very strong chance (60-80%) that heat advisories will be needed for coastal areas and perhaps some coastal valleys areas starting as early as Thursday and especially into Friday.
(Fri-Mon), 12/208 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 slowly cooling into 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 some potential is tracks just enough offshore to support some shower activity.
13/0006z.
At 00Z at KLAX, A moist layer was present up to 8000 feet.
Overall, moderate confidence in TAFs. There is a threat of isolated sprinkles or very light showers across LA county until sundown. There will be 20-40% chance of MVFR CIGs through early evening across KLAX, KSMO, KLGB, KBUR, AND KVNY.
KLAX, Moderate confidence in TAF. There is a threat of isolated sprinkles or very light showers at KLAX until sundown. There is a 30% chance of MVFR CIGs through early evening. A slight north to northeast winds component will most likely develop on Tuesday morning, but expected to remain 6 knots or less.
KBUR, Moderate confidence in TAF. There is a threat of isolated sprinkles or very light showers at KBUR until sundown. There is a 30% chance of MVFR CIGs through early evening. A slight north to northeast winds component will most likely develop on Tuesday morning, but expected to remain 6 knots or less.
12/755 PM.
For the Outer Waters, moderate to high confidence in current forecast. On Tuesday afternoon and evening, there is a 40-60% chance of SCA level winds around Point Conception. For Wednesday through Saturday, high confidence in winds and seas remaining below SCA levels.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. For Tuesday Wednesday, there is a 30% 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 Tuesday afternoon and evening. On Thursday and Friday, there is a 40-60% chance of SCA level northeast winds from Ventura south to Santa Monica.
Long period swell 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.
12/804 PM.
While the peak timing for the most impactful coastal flooding has passed, there is still a threat of minor to moderate coastal flooding through Tuesday, due to continued high tides and elevated surf. The highest tides will occur during the mornings and range from 7.0 to 7.5 feet through Tuesday, with secondary high tides during the evenings (around 6 feet tonight decreasing to 5 feet by Tuesday evening). As for elevated surf, a long period southerly swell and long period westerly swell will impact the coastal waters the next several days.
The Coastal Flood Advisory for the San Luis Obispo and Santa Barbara coasts are in effect until later this evening, and the rest of the coasts the Coastal Flood Advisory will continue until Tuesday afternoon. The Beach Hazards Statement for Santa Barbara South Coast will continue into Tuesday afternoon for a combination of elevated surf and minor tidal overflow during high tides.
A Beach Hazards Statement Tuesday through Thursday morning will likely be issued following the Coastal Flood Advisory expiration on Tuesday for the LA/Ventura County Beaches. This is due to minor tidal overflow continuing to be possible during morning high tides (remaining around 6.5 feet) and the 2 foot 15-16 second southerly swell continuing to impact the area.
Please continue to monitor the forecast and refer to the Coastal Hazard Product (CFWLOX) for more information.
Ca, Coastal Flood Advisory in effect until 2 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). Beach Hazards Statement in effect through Tuesday afternoon for zones 349-350-354-362-366. (See LAXCFWLOX). PZ, NONE.
