20/743 PM.
After a chilly start to the day on Saturday, a warming trend will take shape through the weekend. Temperatures will remain below normal into Saturday but then rise above normal on Sunday. Chances for rain next week continue to fade with an upper-level trough likely taking a track into northern California.
(Fri-Mon), 20/832 PM.
***UPDATE***
Another cold night is on tap for Southwestern California, with mostly clear skies and light winds allowing for efficient radiational cooling. Freeze Warnings have been issued for the Cuyama Valley and Antelope Valley foothills, with Frost Advisories for the Ventura valleys and the San Fernando Valley, where lows in the lower to mid 30s are expected. There is the small chance for patchy low clouds to form overnight tonight due to all the recent rain. Winds will shift to weakly offshore overnight, increasing some during the mid- morning hours. The combination of high pressure building aloft with offshore trends will result in a warming trend over the next few days, with warmer temperatures forecast for Saturday, especially for Ventura and L.A. Counties west of the mountains.
Mostly clear skies are expected to persist through the short term, aside from occasional high clouds moving over the region. As a ridge aloft builds over the area, along with continued offshore breezes, warming will continue into early next week.
***From Previous Discussion***
Overall, 12Z models in good synoptic agreement through the short term period. At upper levels, ridge will gradually build through the weekend, peaking in strength on Monday (582-586 DM heights). At the surface, offshore flow will gradually strengthen, peaking on Monday.
As for temperatures, the combination of building upper level ridge and increasing offshore surface gradients will bring a welcome warming trend to the area. By Sunday, most areas will be 2-6 degrees above normal then about 6-12 degrees above normal on Monday. As for overnight lows, tonight will be another chilly night, but should be a degree or two warmer than this morning. So, at this time, will not issue any Frost/Freeze products, but future shift may need to reevaluate that possibilty.
(Tue-Fri), 20/207 PM.
For the extended, 12Z models continue to exhibit good synoptic agreement. At upper levels, ridge weakens a bit on Tuesday and Wednesday, but will rebound on Thursday and Friday. Near the surface, weak onshore flow will prevail Tuesday and Wednesday, but offshore flow will begin to return Thursday and Friday.
On Tuesday and Wednesday, models continue to shift a weak atmospheric river further northward. So, the rain chances for the area are very limited. At this time, there is a chance for light rain across San Luis Obispo county (amounts around 0.10 inches or less), but dry conditions are likely elsewhere. This matches up well with the latest ensembles which only have a few members indicating any measurable rain south of Point Conception. With the weak onshore flow and slight weakening of the upper ridge, temperatures will be a couple degrees cooler across most areas.
For Thursday and Friday, dry conditions are expected. Temperatures will gradually warm, due to the building ridge and weak offshore flow. There will be some offshore winds, but they look to be on the weak side.
21/0255z.
At 0011Z at KLAX, no inversion and no marine layer were present.
High confidence in TAFs with VFR conditions and light winds through the period. 10% chance for VLIFR conds at KPRB after 10Z.
KLAX, High confidence in VFR TAF. No significant east wind component expected.
KBUR, High confidence in VFR TAF.
20/745 PM.
For the Outer Waters, moderate to high confidence in current forecast. Seas have subsided below the Advisory level of 10 feet this evening. For Saturday, there is a 40-60% chance of SCA level southerly winds in the late afternoon and overnight hours, highest across PZZ670. Moderate confidence in conditions remaining below SCA levels Sunday and Monday, then NW winds are expected to increase Tuesday.
For the Inner Waters north of Point Sal, moderate confidence in conditions remaining below SCA levels through Tuesday.
For the Inner Waters south of Point Conception, high confidence in conditions remaining below SCA levels through Tuesday.
Ca, Freeze Warning remains in effect from midnight tonight to 9 AM PST Saturday for zones 38-381-382. (See LAXNPWLOX). Frost Advisory in effect from midnight tonight to 9 AM PST Saturday for zones 88-357-358-371-372-374-375. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from 3 PM Saturday to 3 AM PST Sunday for zone 670. (See LAXMWWLOX).
