Marine Weather and Tide Forecast for Rossmoor, CA

.SHORT TERM (TDY-WED)...20/221 PM.

The region will remain beneath broadly cyclonic flow aloft between a series of impulses tracking across the Pacific Northwest, and a subtropical stream south of the international border. Patches of high clouds will be advected over the area as flow peripheral to the impulses grazes the subtropical stream. However, it will remain adequately dry in the mid-levels to prevent precipitation from occurring. Larger-scale pressure gradients will trend increasingly onshore through early this week, while mean upper troughing north of the area re-positions westward. This will foster an increase in low clouds and night through morning fog especially near the coast. Temperatures will be near normal to a couple degrees below normal across the region through early and middle parts of this week, with highs generally in the 70s except 60s near the beaches and lower 80s in parts of the Antelope Valley.

.LONG TERM (THU-SUN)...20/221 PM.

Later in the week and into next weekend, medium-range model guidance indicates a higher-amplitude trough and perhaps deep cyclone developing in the vicinity of the Pacific Coast. Model solutions vary significantly regarding the details of these features, though perturbation trajectories should remain far enough inland to minimize precipitation chances. The main effects from this system will be temperatures cooling by a couple of degrees late this week into next weekend, as midlevel heights fall. The falling midlevel heights could also initially support drizzle development in the deepening marine layer. In addition, northwest to north pressure gradients will trend offshore as a result of strong surface high pressure building upstream of the trough over the Pacific waters. In addition, low clouds and fog will eventually be shunted southward, becoming confined to LA County and vicinity -- and perhaps dissipating by next weekend as cooling aloft with the trough erodes the inversion surmounting the marine layer.

AVIATION
21/0026Z.

At 00Z at KLAX, the marine inversion was 1000 feet deep. The top of the inversion was 2000 feet with a temperatures of 18 degrees Celsius.

For 00Z TAF package, high confidence in KBUR
KVNY
KWJF and KPMD. For all other sites, moderate confidence due to some uncertainties in behavior of marine layer stratus. North of Point Conception, timing of flight category changes could be +/- 2 hours of current forecasts. For coastal sites south of Point Conception, there is a 60-80% chance of IFR/LIFR CIGs and VSBYs after 06Z tonight.

KLAX...Overall, moderate confidence in 00Z TAF. For tonight, moderate to high confidence in return of CIG/VSBY restrictions with timing of return +/- 2 hours of 00Z forecast. No significant easterly wind component is expected.

KBUR...High confidence in 00Z TAF.

MARINE
20/1249 PM.

For the Outer Waters, moderate to high confidence in current forecast. Through Monday, there is a 20% or less chance of Small Craft Advisory (SCA) level winds around Point Conception. For Tuesday afternoon through Friday, there is an 80% chance of SCA level winds across the Outer Waters.

For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through Tuesday, high confidence in winds and seas remaining below SCA levels. For Wednesday through Friday, there is a 50% chance of SCA level winds in the afternoon and evening hours.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Through Friday, high confidence in winds and seas remaining below SCA levels across most areas. The only exception will be the western half of the Santa Barbara Channel where there is a 30% chance of SCA level winds Wednesday through Friday, mainly during the late afternoon through evening hours.

LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.