05/1155 AM.
Much cooler temperatures are expected Friday as a weak upper low moves into the area. Warmer temperatures will return Saturday and peak Sunday with highs around 10 degrees above normal. A return to normal temperatures is expected by next Tuesday with a chance of light rain.
(tdy-Sun), 05/1225 PM.
Another warm, offshore flow day across the area with highs in the 70s and 80s. Most areas cooled at least a few degrees from yesterday as gradients trended onshore and some high clouds moved overhead during the time of peak heating. Changes are finally coming to the overall weather pattern but there remains a lot of uncertainty on timing and we're not completely done with the hot weather just yet.
In the very short term, significant cooling is expected tomorrow as gradients actually turn onshore for the first time in several days. Some patchy low clouds and fog are possible near the coast in the morning and by afternoon most areas should be at least 5-10 degrees cooler than today. This is the result of a weak upper low splitting off from a trough in the Pac NW and moving into our coastal waters region Friday and then moving onshore over northern Baja on Saturday. The low has some energy associated with it as demonstrated by the cooling cloud tops a few hundred miles west of Pt Conception. Models are picking up on this as well, showing some weak instability tomorrow, mainly over the mountains. This is likely what the ensemble models were seeing earlier in the week when they were indicating some possibilities for light precip in the area Friday. This is still not a zero chance, and if something happens it would more likely be an isolated dry lightning strike in the mountains. But also can't rule out a brief and isolated light shower just about anywhere. Chances are less than 15% and thus not enough to put in the official forecast.
The upper low will exit the area by Friday night with dry and warmer conditions Saturday and peaking Sunday as gradients turn back offshore and high pressure aloft returns. Not expecting a return of advisory level northeast winds but could see some breezy conditions in the usual areas that are favored for Santa Ana winds. Highs expected to return to the low to mid 80s across the valleys by Sunday (or possibly as early as Saturday) and some coastal areas as well.
(Mon-Thu), 05/1238 PM.
High pressure aloft will begin to shift east out of the area Monday but not before another day of well above normal temperatures.
Much cooler temperatures are expected Tuesday and the rest of next week as the upper level pattern finally changes to more of a troughy pattern along the West coast. The first chance for rain still appears to be on Tuesday and models continue to indicate just a very light amounts of precip with that one, likely under a quarter inch in most areas. And there are at least 20-30% of the ensemble solutions showing little or no rain with this first system.
There's a second and third system later in the week into early the following week (between the 14th and 18th), the latter of which appears to be the strongest of the trio. Up until that time, most of the models are favoring mostly just light rain amounts. But there is overall high confidence in much cooler temperatures locally.
05/1839z.
At 0852Z at KLAX, there was no marine layer nor an inversion.
High confidence in TAFs, until 09Z Fri when MVFR cigs become possible at coastal sites south of Point Conception. However, there is a 40% chance of VFR conditions through the period at sites where cigs are forecast, and heights may be off by +/- 500 ft.
KLAX, High confidence in TAF, until around 09Z Fri when BKN010-BKN025 cigs become possible. However there is a 40% chance of VFR conditions through the period. Good confidence that any east wind component will be under 8 kt.
KBUR, High confidence in TAF, except for after 12Z there is a 10% chance of BKN010-BKN025 cigs developing.
05/206 PM.
Long period westerly swell will build tonight across the outer waters, and seas are likely to reach Small Craft Advisory (SCA) levels by Friday morning across the Outer Waters and nearshore along the Central Coast. The hazardous seas could last through Saturday evening especially south of Point Conception. Additionally, the westerly swell may cause issues at Morro Bay and Ventura Harbor Friday through early Saturday morning.
There is moderate chance for winds to reach SCA levels across the Outer waters late Saturday afternoon into evening hours, with the greatest chances for the waters west and south of the Channel Islands. Confidence is higher that by Sunday afternoon/evening SCA level winds will become widespread, and these winds may persist well into next week. SCA winds have the potential to spread into the Santa Barbara Channel & western portions of the PZZ655. There is also a chance for GALES across climatologically favored outer waters. Elevated up to SCA level seas are also possible, as several rounds of swells propagate into our coastal waters mid- week.
05/210 PM.
An active storm pattern over the northern Pacific Ocean will generate a series of swells which will propagate towards our coastline, first arriving on Friday and lasting well into next week. There is a high chance of an extended period of elevated surf. Advisory level surf is expected Friday through Saturday for all beaches, though the highest swell will be across west facing coasts. Additional high surf will be possible through Monday into Tuesday (and possibly longer) especially for the Central Coast and Ventura County Coast.
Peak surf heights are likely to be between 10 to 15 ft for west- facing beaches along the Central Coast, and between 5 and 10 ft south of Point Conception. Additionally, the long period westerly swell may cause issues at Morro Bay and Ventura Harbor Friday through early Saturday morning.
Ca, High Surf Advisory in effect from midnight tonight to 6 PM PST Saturday for zones 340-346-349-350-354. (See LAXCFWLOX). High Surf Advisory in effect from 6 AM Friday to 6 PM PST Saturday for zones 362-366. (See LAXCFWLOX). PZ, Small Craft Advisory in effect from 3 AM Friday to 3 PM PST Saturday for zones 645-670-673. (See LAXMWWLOX). Small Craft Advisory in effect from 9 AM Friday to 3 PM PST Saturday for zone 676. (See LAXMWWLOX).
