18/720 PM.
Very nice weather will continue into early next week with maximum temperatures within 5 degrees of normal for most of the region through Monday. Dense coastal fog will be possible Sunday and Monday mornings. Then a weak upper low will swing across southern California Wednesday, bringing cooler weather with a chance of drizzle or light rain. There is another chance of rain next weekend.
(Sat-Tue), 18/811 PM.
***UPDATE***
Mainly quiet weather is expected through the short term, other than a chance of low clouds returning to some near-coastal areas tonight with a likelihood of patchy dense fog if the clouds materialize. While models hint at this solution, the low cloud/fog coverage appears somewhat limited with a better chance of more widespread low clouds and fog Sunday night into early Monday. Light north winds along the Santa Barbara South Coast will keep that area clear. Gusts there are around 15 to 25 mph, otherwise mainly light winds are currently affecting the 4-county area.
Once any low clouds clear Sunday morning, sunny skies and slightly cooler temperatures are expected. Highs will lower around 3 to 6 degrees across most of Ventura and LA Counties, and 5 to 10 degrees along the Central Coast. The Antelope Valley may warm a couple of degrees.
Overall expect to see continued gradual cooling through Tuesday as surface pressure gradients trend to weakly onshore.
(Wed-Sat), 18/202 PM.
A weak upper low that has been spinning about 600 miles southwest of southern California will finally start drifting slowly to the northwest Tuesday based on the last few sets of ensemble solutions. There are still some uncertainties with the timing as it could arrive as early as Tuesday or as late as Wednesday night or early Thursday. But more than 50% of the solutions support the Wednesday timing. While there isn't a ton of moisture with it, the cooling aloft as the upper low moves overhead will likely deepen the marine layer considerably, creating an environment that would be favorable for areas of drizzle or very light rain. Based on the forecast trajectory of the low the most likely areas for light precip would be south of Pt Conception, though deep marine layer would be present along the Central Coast as well. Clouds may linger for most of the day, leading to high temperatures that are 5-10 degrees below normal area-wide, and possible as much as 15 degrees in areas with precip.
The latter half of the week will feature temperatures rebounding back to near normal as a brief ridge fills in. The southern edge of a trough which is lining up to be a significant rain maker for the northern half of the West Coast will clip Southwest California by Saturday afternoon. Although the trough does not appear to dig far enough south south to bring significant rain to our area, ensembles are bullish on the Central Coast receiving light measurable rain. There is less agreement south of Point Conception, but a number of solutions bring some precipitation all the way down to LA County by Saturday night.
19/0521z.
At 0444Z at KLAX, there was a surface based inversion to 2000 ft with a temperature of 25 C.
High confidence in TAFs for KPRB, KBUR, KVNY, KPMD, and KWJF.
Moderate confidence in TAFs for KSMX and KSBA. 20% chance for brief LIFR conds at KSBA from 12Z-17Z. 40% chance for 1/4SM vsbys while cigs are present.
Low confidence in remaining TAFs. Flight cat changes may be off +/- 2 hours. There is a 30% chance for VLIFR to LIFR conds at KOXR and KCMA from 10Z-18Z. For LA coastal TAFs, 40% chance for no low clouds to establish, but if cigs arrive, 30% chance for VLIFR conds. For KSBP, there is a 30% chance conds remain VFR, but if cigs arrive, 50% chance for VLIFR conds.
KLAX, Low confidence in TAF. There is a 40% chance that conds remain VFR through the period. If cigs arrive, 30% chance for 1/2SM to 1SM vsbys and/or OVC002 cigs. Flight cat changes may be off +/- 2 hours. No significant east wind component is expected.
KBUR, High confidence in TAF.
18/704 PM.
For the Outer Waters, moderate to high confidence in current forecast. Tonight through Monday, high confidence in winds remaining below Small Craft Advisory (SCA) levels, however moderate confidence in seas with heights nearing 10 feet across PZZ670. On Monday, there is a 60-80% chance of SCA level seas building to near or above 10 feet across PZZ670/673. On Tuesday, high confidence in winds and seas remaining below SCA levels. For Thursday through Friday, there is a 30-40% chance of SCA level winds, especially across PZZ673/676.
For the Inner Waters north of Point Sal, high confidence in current forecast with winds and seas expected to remain below SCA levels through Thursday.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For a majority of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Thursday. The only exception will be the western half of the Santa Barbara Channel where there is a 20-30% chance of SCA level winds Wednesday through Thursday, mainly during the late afternoon and evening hours.
Tonight into early next week, there is an increasing chance of dense fog developing.
Ca, NONE. PZ, NONE.
