Swell Matrix

Area Forecast Discussion

National Weather Service Los Angeles/Oxnard Ca

914 pm PDT Sun aug 14 2022

Synopsis

14/141 PM.

Above normal temperatures will continue through most of the week, peaking Wednesday and Thursday. Skies will be mostly clear except for night through morning low clouds and fog along the Central Coast. Monsoonal showers or thunderstorms may return to eastern areas later in the week.

Short Term

(Sun-Wed), 14/907 PM.

Mostly clear skies were present this evening above a shallow marine layer stratus filling in along the Central Coast and extending to the to outer waters. Northwest to onshore pattern remained in place with a Santa Barbara to Santa Maria -3.5 gradient supporting a bit stronger Sundowner winds than anticipated for southwest Santa Barbara county. Even still gusts to around 40 mph in wind prone areas such as Refugio and Gaviota slot in just below advisory level.

Low clouds and patchy dense fog will continue to fill into the Central Coast, likely pushing into lower portions of the Santa Ynez valley. Pooling of low clouds of the San Diego county coast, a weak eddy, and increased ensemble support all point to increased low cloud and fog coverage late tonight into Monday morning for the South Bay area and possibly nosing north to some other coastal areas of Los Angeles and Ventura counties. Some mild fog may form in place in other coastal areas.

Benign weather continues into Monday afternoon with some cooling possible immediate coastal areas south of Point Conception thanks to the increasing marine layer influence. All other areas will be similar if not warmer Monday than it was today.

***From Previous Discussion***

High pressure over the western states will remain in place through the forecast period at least. Most ensembles favor a slight warming trend through mid week. Considering we've been teetering on heat advisory criteria the last few days the slight warm up coming this week will likely push some interior areas over the edge by Wednesday, especially with overnight lows warming up as well.

Besides the continued warmer than normal temps the weather locally is pretty quiet. Marine layer stratus has made a partial return to southern coastal areas but onshore flow remains light and high pressure aloft will keep the depth under 1000'. So for areas south of Pt Conception most likely it will only clip the beaches but could possibly reach some coastal airports. Along the Central Coast low clouds and areas of dense fog will continue through the night and morning hours.

Pretty impressive monsoon push across AZ and extreme southern California with dewpoints as high as 80 in the southeast deserts south of Palm Springs. However, models continue to keep most of that east of LA County and not expecting much locally other than some afternoon cu buildups over the eastern San Gabriels. Chances for thunderstorms do increase later in the week the models continue to show a slight westward shift in the monsoon and increasing instability.

Long Term

(Thu-Sun), 14/200 PM.

High pressure remains in place through the weekend and into early next week so above normal temperatures will continue. However, onshore flow will be increasing later in the week that will likely bring at least a few degrees of cooling to coast and valleys. The threat of afternoon monsoon thunderstorms continues to get pushed farther into the extended period and it now looks like at least Thursday before there's even a small chance of storms across the eastern mountains and deserts. And even that's looking pretty unlikely as the 12z GFS and the EC/GEFS ensembles both show minimal instability and moisture even into next weekend. So it looks like our CWA will continue to be on the outside looking in with regard to convective activity for the next several days.

Aviation

15/0002z.

At 23Z at KLAX, the marine layer was around 600 ft deep. The top of the inversion was at 2100 ft with a temperature of 27 deg C.

High confidence in VFR conds for valley to desert TAFs.

High confidence that KSMX and KSBP will have an early return IFR or lower cigs/vsbys tonight. Timing of return may be off by 2 hours.

Moderate confidence in other coastal TAFs, except low confidence in KLGB. Flight category changes may be off by 2 hours and one category. There is a 30-50 percent chance (highest KLGB) of IFR or lower cigs after 08Z for immediate coastal terminals.

.KLAX, Moderate confidence in the TAF. There is a 30 percent chance of IFR cigs/vsbys sometime between 10-17Z. Any east wind component will be 5 kt or less.

KBUR, High confidence in VFR conditions thru the period.

Marine

14/911 PM.

Forecast is trending well this evening, although isolated Gale conditions are likely through very early Monday morning. Local Small Craft Advisory (SCA) conditions may persist for the inner waters north of Point Sal through very early Monday morning. Have updated the forecast to reflect the slightly stronger winds and seas.

In the outer waters, Small Craft Advisory (SCA) level winds will continue thru late Mon night. There is a 50% chance that SCA conds will persist Tue through Thu evening mainly for the western portion of zones 670 and 673. SCA conds are also possible Thu through Fri.

Across the inner waters north of Pt. Sal, is a 30% chance of SCA conds Tue afternoon/evening and again from Thu through Fri.

In the SBA Channel, there is a 30% chance of SCA conditions Thu and Fri afternoons.

In the southern inner waters, there will be locally gusty west winds from Anacapa Island to Malibu Thu afternoon and evening, otherwise, SCA conds are not expected.

Watches, Warnings, Advisories

Ca, NONE. PZ, Small Craft Advisory in effect until 3 AM PDT Tuesday for zones 670-673-676. (See LAXMWWLOX).

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