Marine Weather and Tide Forecast for Pismo Beach, CA

.SHORT TERM (TDY-SUN)...16/933 AM.

***UPDATE***

The marine layer has deepened to around 3000 feet this morning in response to the next upper level trough approaching the West Coast. Onshore flow is trending strongly onshore today and that will continue into Saturday. Temperatures are already trending cooler this morning across coast and valleys, in some areas by as much as 10 degrees. Overall, most areas will end up 3-6 degrees cooler than yesterday, with the marine layer only slowly clearing through the morning and early afternoon.

***From Previous Discussion***

Saturday, when the marine influence looks to be greatest, looks to the be the coolest day of the period. Temperatures around the 60s to lower 70s will be common across the coastal and valley areas and clouds will likely struggle to clear and there may be some areas of drizzle.

Gusty onshore winds will develop between Saturday and Sunday night due to strong onshore pressure gradients. Advisory level winds are likely along the coastal areas and across the interior valleys, especially each afternoon and evening. The dying frontal boundary will slide south over the area on Saturday and the pattern will shift the wind from southwest to west on Saturday to west to northwest between Saturday night and into Sunday. Wind advisories will likely be needed for most coastal areas and the Antelope Valley on Saturday and Sunday, and through the Interstate 5 Corridor and across southern Santa Barbara County on Saturday night and into Sunday.

The northerly pressure gradient will likely tighten again on Sunday night into Monday. There is a low-to-moderate chance of warning level winds developing through the Interstate 5 Corridor and across southern Santa Barbara County. A few solutions of the EPS members indicate warning level gusts at KSDB, while the latest NAM-WRF solutions indicate 45-50 knots of wind at 850 mb across the Transverse Ranges on Sunday night. Further hinting at the possibility, ECMWF EFI values highlight the Transverse Ranges on Sunday night, while NAEFS standardized anomalies nosing 850-700 mb winds between 3 and 4 standard deviation versus the CFSR period over the Central Coast. Wind advisories are likely to be issued for Sunday night when the timing and finer details come together, but the High Wind Warning potential will need to be watched closely.

.LONG TERM (MON-THU)...16/405 AM.

Gusty northerly winds are likely to persist into Monday morning as the surface pressure gradients remain tight.

Confidence remains high for a warming trend for next week as high pressure aloft will build in over the region. While there is some uncertainty for Monday, EPS 500 mb height means climb through at least Thursday. By Wednesday or Thursday, EPS high temperature means suggest values in the 90s being common for the valleys, foothills, and desert, while temperatures in the 80s to lower 90s could be common across the coast. Deterministic ECMWF solutions support the idea of warming as pressure gradients weaken substantially to near neutral or light offshore. NBM solutions give about a 15 percent chance of KPMD and KWJF of hitting 100 degrees, which if it occurred would be about three weeks earlier than normal. Away from the coast, the temperature forecast leans more heavily into the 75th percentile of NBM solutions between the period between Wednesday and Thursday night. Experimental NWS heat risk values climb for Wednesday and Thursday, trending toward a period potentially dangerous heat.

AVIATION
16/1746Z.

At 1640Z at KLAX, the marine inversion was around 3000 feet deep.
The top of the inversion was 4500 feet with a temperature of 14 degrees Celsius.

High confidence in TAFs for KWJF and KPMD.

Moderate confidence in TAFs for remaining sites. There is a 30% chance for IFR to MVFR cigs between 12Z and 18Z at KPRB. Coastal sites forecast to clear have a 30% chance of not clearing, and 30% chance for sites forecast to not clear to SCT. Dissipation of cigs may be off +/- 2 hours, and arrival may be off +/- 3 hours.
Minimum flight cat may be off by one cat for KSBP/KSMX.

KLAX...Moderate confidence in TAF. There is a 30% chance for cigs to SCT between 20Z and 03Z. Cigs may SCT tomorrow between 20Z and 00Z. There is a 20-40% chance for an east wind component of 8 kts between 11Z and 18Z. Best chances between 14Z and 18Z.

KBUR...Moderate confidence in TAF. Return of cigs may be off +/- 3 hours, and there is a 20% chance for cigs 007-009.

MARINE
16/806 AM.

For the Outer Waters, moderate confidence in current forecast.
Today through Tuesday, high confidence in combination of Small Craft Advisory (SCA) level winds and seas. For Saturday afternoon through Sunday night, there is a 50-60% chance of Gale force winds, with higher chances Sunday afternoon through late night.

For the Inner Waters, moderate confidence in current forecast.
Today through Sunday night, high confidence in SCA level winds, especially in the afternoon and evening hours. There is a 50% chance of Gale force winds Saturday afternoon through Sunday evening. For Monday through Tuesday, there is a 50-70% chance of SCA level winds continuing.

For the Inner Waters south of Point Conception, moderate confidence in current forecast. Through Saturday morning, high confidence in winds and seas remaining below SCA levels. For Saturday through Sunday night, high confidence in SCA level winds, focus through the Santa Barbara and western sections of the southern Inner Waters. Additionally, there is a 50% chance of Gale force winds across the Santa Barbara Channel Saturday evening through Saturday night, with a 30% chance Sunday afternoon through late night. For Monday through Tuesday, high confidence in winds and seas remaining below SCA levels.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory in effect from 10 AM to 9 PM PDT Saturday for zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zone 645. (See LAXMWWLOX).
Gale Watch in effect from Saturday afternoon through late Saturday night for zones 645-670-673-676. (See LAXMWWLOX).
Gale Watch in effect from Saturday evening through late Saturday night for zone 650. (See LAXMWWLOX).
Small Craft Advisory in effect until 2 PM PDT Saturday for zones 670-673-676. (See LAXMWWLOX).