11/312 AM.
One more day of sunny, warm and dry weather. A noticeable cooling trend will start Thursday, with temperatures falling to near normal by Friday. Rain is expected area wide Friday into early Saturday and again next Monday.
(tdy-Fri), 11/312 AM.
One more very pleasant day on tap as the ridge tries to hang on as a large trof begins its push to the east. Weak offshore flow will keep the low clouds away and it will be a sunny day. 582 dam hgts and the offshore flow will bring max temps from the lower to mid 80s to the csts and mid 80s to lower 90s for the vlys. Most max temps will be about 12 degrees over normal.
For those wondering how unusual these temperatures are for this long, it's actually not that rare. We're actually just barely cracking the top 20 where highs were 80 degrees or higher in Downtown LA, the longest being 14 days straight days in 1890, and more recently 7 days in 2008 and 2016.
On Thursday the trof will move closer to the coast and will begin to pinch off a cut off low at its base. The upper flow over Srn CA will turn to the SW. Hgts will fall to 576 dam and onshore flow will return. Morning low clouds are possible across the Central Coast. Look for about 6 degrees of cooling across the board.
On Thursday night the upper low will start to move to the SE missing the CA coast and moving into Baja Friday morning. This system does not look to be much of a rainmaker and may be too far to the west to really affect the Central Coast. Areas south of Pt Conception have a better shot at rain. The far interior will likely see no rain at all. Rain totals will be around a tenth to a quarter inch with inconsequential rainfall rates.
The rain from the upper low should end late morning or early afternoon. At this time round 2 of the rain will start. A cold front assoc with a powerful storm off of the coast of British Columbia will begin to move into SLO county from the NW either later in the afternoon or more likely in the evening. This front will move through the area from the NW to the SE and should exit the area around noon Saturday. This front will bring a period of steady rain to all of the area. This system should bring about a third of an inch to a half inch of rain to most areas except the interior sections will see about half as much. The Central Coast may see a little more rainfall as well. Rainfall rates with this system will be heavier than those in the earlier system but should not reach any critical thresholds. Snow levels will remain above 8000 ft.
Look for 4 to 8 degrees of cooling Fri with an additional 3 to 6 degrees likely Saturday. This cooling will bring below normal temps to the area.
(Sat-Tue), 11/312 AM.
Sunday should be dry with partly cloudy skies as a little pop up ridge in between storms moves over the area. There will not be much warming, however, and max temps across the csts/vlys will end up in the mid 60s to lower 70s.
A colder trof will 556 dam hgts will sweep through the state some time during the early Monday to early Tuesday period. The system is moving at a good clip and exact timing will take a few more days to narrow down. Most areas can expect 3 to 6 hours of rain from this system. This system is a little more unstable and showery, but also drier due to how cold it is. Early rainfall estimates call for a tenth to a third of an inch of rain. There is a higher potential for localized heavier rainfall rates under convective showers with this system. Snow levels will be lower than Saturday's system but will still be above 7000 ft. Monday will be a cool day with highs only in the 60s.
Tuesday should be dry much like Sunday as it will be an in between storm day.
More rain is possible either Wed or Thu, but there is considerable mdl confusion on the exact details and timing.
11/1112z.
At 0828Z at KLAX, there was a surface based weak inversion. The top of the inversion was at 1000 ft with a temp of 26 C.
Moderate confidence in KPRB, KSMX, and KSBP where there is a 20% chance for brief cigs 12Z-16Z.
Good confidence in TAFs for KLAX, KSMO and KLGB with a 10 percent chc of IFR/LIFR cigs 12Z-15Z.
High confidence in TAFs for all remaining sites. KLAX, Good confidence in TAF. There is a 10 percent chc of BKN005 conds 12Z-15Z. Lower confidence in cld fcst aft 12/10Z. Any east wind component is expected to remain below 7 kts.
KBUR, High confidence in TAF.
11/312 AM.
For the Outer Waters, moderate to high confidence in current forecast. Seas will remain slightly below SCA levels through Wednesday. Expecting 10+ ft seas to return Thursday through at least Sunday, with models indicating potential for wave heights 15 to 20+ ft. At this time the peak looks to be Saturday afternoon into early Sunday. As for winds, SCA winds are likely near and south of Point Conception Friday night through Saturday night.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Conditions are expected to remain below SCA levels through Thursday. SCA level seas could return as early as late Thursday night or Friday, peaking over the weekend. Gusty SCA level winds are possible nearshore Friday night through Saturday afternoon.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Winds and seas are expected to remain below SCA levels for the southern Inner Waters through Thursday. SCA winds will then be possible at times Friday night through Saturday.
There is concern for a large westerly swell this weekend which could produce dangerous breaking waves at Ventura and Morro Bay harbor entrances.
There is a chance of showers sometime from Thursday night into the weekend across the coastal waters.
10/1026 PM.
A very large, long-period west to northwest swell originating from a strong Aleutian low pressure system will arrive at the beaches this weekend. Impacts will be focused along west to northwest facing shores and are 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 longshore currents, potential sneaker waves and large shore pound. Impacts will be less for south-facing shores.
The highest risk will be along the Central Coast with potential for localized damage to the most vulnerable areas. Oceano Dunes State Park flooding with limited to no vehicle access is likely. If guidance remains consistent, WARNING-level surf is likely and a coastal flood watch may be needed to highlight the moderate potential for WARNING-level coastal flooding.
For LA/VTA west-facing beaches, there is potential for at least advisory level surf and cannot rule out a High Surf WARNING especially for the Ventura coastline.
Coastal hazards are likely to continue well into next week as the northern Pacific remains very active.
Ca, Beach Hazards Statement in effect through Monday morning for zones 87-349-350-354-362-366. (See LAXCFWLOX). High Surf Advisory in effect until noon PST Monday for zones 340-346. (See LAXCFWLOX). PZ, NONE.
