Marine Weather and Tide Forecast for Rossmoor, CA

.SHORT TERM (TDY-WED)...25/957 AM.

***UPDATE***

Marine layer clouds have been very slow to develop this morning and many areas have remained clear. Cloud that have formed will likely burn off earlier in the day than yesterday. Main focus of today's forecast will be winds Tuesday afternoon and night and the small chance of precipitation with the low pressure system that will impact the region Tuesday through Thursday.

***From Previous Discussion***

Today will be the last day with near normal temperatures until late in the week. Although low clouds have been slow to form, a weak to moderate eddy will likely support low clouds into at least coastal sections of LA County with broad northwest onshore flow also favoring the Central Coast and adjacent valleys.
Low clouds that are established by morning will likely burn off a bit faster than previous days.

Below normal forecast confidence for the Wednesday into Thursday timeframe related to uncertainty in the track and resulting impacts associated with notoriously difficult to forecast cut-off low pressure systems.

A potent (for late May) cold cut- off low pressure system has trended further south and west and closer to Southwest California for the Wednesday and Thursday time frame in particular. This places increased confidence toward enhanced southwest to northwest winds across the region by Tuesday with the potential for additional wind advisories especially for San Luis Obispo and Santa Barbara Counties. A deepening marine layer will likely bring drizzle at times especially Tuesday and Wednesday mornings just about anywhere low to mid level clouds occur. By Wednesday we'll likely have a deep moist layer with sufficient dynamics and shallow instability for a 10-30 percent chance of generally light showers or drizzle, highest across the interior mountains. Snow levels may dip to 6000-8000 feet, lowest at night, potentially supported a rain/snow mix at times for high elevations. The closer proximity of the system also brings with it sufficient instability to warrant a small (5-10 percent chance) of a thunderstorm focused across interior mountains and valleys of San Luis Obispo, Santa Barbara, and Ventura Counties mid afternoon Wednesday to the evening hours. Gusty winds, brief heavy rain and cloud-to-ground lightning look to be the main threats should a thunderstorm occur.

.LONG TERM (THU-SUN)...25/115 AM.

The low pressure system may remain parked in the region into Thursday with additional rotating spokes of moisture and energy around the weakening system retaining at least a small chance of showers across the region, perhaps focused across San Luis Obispo and Santa Barbara Counties.

Friday through Sunday temperatures will trend upwards as the low travels to the east, becoming within a few degrees of normal over the weekend (highs in the low 70s to low 80s for coast and valleys). Moderate strength onshore surface pressure gradients will continue, thus some coverage of marine layer stratus is likely each night and morning, and breezy onshore afternoon to evening winds will continue for the Antelope Valley and likely return in the form of Sundowner winds for southwest Santa Barbara County.

AVIATION
25/1726Z.

At 1609Z at KLAX, the marine layer was 2900 ft deep. The top of the inversion was at 4000 ft with a temperature of 13 C.

High confidence in VFR TAFs for desert airfields (KPMD & KWJF).

Moderate confidence in remaining sites. Timing of flight cat changes may be off +/- 2 hours and minimums by one category.
Marine layer -DZ is possible when CIGs are present.

KLAX...Moderate confidence in TAF. Arrival and clearing times of MVFR CIGs should be accurate within +/- 2 hours of current forecast. CIGs most likely to rise above 2,000ft threshold between 13Z-16Z Tuesday. No significant easterly wind component is expected.

KBUR...Moderate confidence in TAF. No wind issues expected.

MARINE
25/808 AM.

For the Outer Waters, moderate to high confidence in current forecast. Through Monday morning, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. Winds will increase to SCA levels Monday afternoon for the waters south of Point Sal to San Nicholas Island. By Tuesday afternoon, high confidence in winds and seas increasing to SCA levels across all outer waters through at least Wednesday night. There is a GALE WATCH for Tuesday afternoon through Tuesday night. Followed by SCA conditions through early Thursday. Thereafter, conditions are likely to fall below SCA levels for a short-time, before returning later Friday into the weekend.

For the Inner Waters north of Point Sal, moderate confidence in current forecast. Through Monday afternoon, high confidence in winds and seas remaining below SCA levels. There is a 30% chance of SCA level winds Monday afternoon and evening. For Tuesday through early Wednesday, high confidence in a combination of SCA level winds (strongest in the afternoon and evening hours) and seas. There is a 40% chance of SCA winds and seas Wednesday afternoon through evening. There is a GALE WATCH for Tuesday afternoon through Tuesday night. From late Wednesday night through Thursday night, conds should drop below SCA levels.

For the Inner Waters south of Point Conception, moderate confidence in current forecast. From this afternoon through tonight, SCA level W to NW winds are expected across the Santa Barbara Channel, around the Channel Islands, and into Santa Monica Channel during the evening hours. On Tuesday and Tuesday night, there is a 90% chance of SCA level winds across the Santa Barbara Channel with a 40-50% chance of Gale force winds. Local Gale Force winds could occur nearshore Anacapa island during this timeframe.
SCA level winds could linger into Wednesday especially across the channel. Otherwise, expecting conditions to fall below SCA levels thereafter.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory remains in effect from 2 PM to 10 PM PDT Tuesday for zones 340-341. (See LAXNPWLOX).
High Surf Advisory in effect from 5 PM Tuesday to 5 PM PDT Wednesday for zones 340-346. (See LAXCFWLOX).
Wind Advisory remains in effect from 6 PM Tuesday to 6 AM PDT Wednesday for zones 349-351. (See LAXNPWLOX).
Wind Advisory remains in effect from 11 AM Tuesday to midnight PDT Tuesday night for zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 8 AM to 4 PM PDT Tuesday for zones 645-670-673. (See LAXMWWLOX).
Gale Watch in effect from Tuesday afternoon through late Tuesday night for zones 645-650-670-673-676. (See LAXMWWLOX).
Small Craft Advisory in effect from 2 PM this afternoon to 1 AM PDT Tuesday for zones 650-655-673-676. (See LAXMWWLOX).
Small Craft Advisory in effect from 10 AM to 4 PM PDT Tuesday for zone 676. (See LAXMWWLOX).