Marine Weather and Tide Forecast for March ARB, CA

DISCUSSION
FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Visible satellite imagery was showing clear skies across Southern California this morning. Easterly winds this morning peaked at 45 mph in the San Diego mountains. The combination of weak offshore flow and a building ridge of high pressure will keep high temperatures today 10 to locally up to 20 degrees above average, with the greatest departure from average along the coast.

An upper level ridge will continue to build over Southern California for the first half of the week. This will maintain well above average temperatures for coastal areas, even further inland in the deserts high temperatures will remain up to 5 degrees above average.
The weak offshore flow is expected to continue through the middle of the week as well although wind gusts are expected to be 35 mph or less. The building ridge and offshore flow will keep marine layer low clouds and fog mostly absent from the coast through at least the middle of the week.

Global ensembles have trended slower with the onset of precipitation late in the week, with slight chances now beginning late Friday.
Significant differences remain in the evolution of the upper level pattern as the jet tries to split. Around 60% of the ensemble members (as well as the deterministic EC and GFS) show a deep closed low in the southern stream and digs it south off the coast of CA and potentially into northern Mexico Saturday. Models are notoriously poor at forecasting the track/timing of such systems, so if this pattern holds the precipitation forecast will likely change - potentially significantly - over the next few days. Around 20% of the members show a weaker open wave developing in the southern stream, which would be more progressive (precipitation starting and ending earlier with less accumulation). The remaining 20% does not produce any split flow with zonal winds across SoCal. Current NBM forecast favors the further south closed low scenario with higher precipitation probabilities over San Diego County on Sunday (60- 70%), decreasing to the north (45-60%). The only certain thing for Friday and Saturday is cooling with increasing cloud cover.

AVIATION
081800...SKC and VFR regionwide. E/NE winds gusting locally 20-35 kts in the San Diego County foothill slopes and in the Inland Empire downwind of the Banning Pass diminish this afternoon, increasing once again Mon after 16z. Otherwise, light W/NW winds around the coast during the day, becoming light E/NE at night.

MARINE
No hazardous marine conditions are expected through Thursday.

BEACHES
High tides will exceed 7 feet each morning through Tuesday, peaking today and Monday at 7.4-7.6 feet. A northwest swell at 2-3 feet with a period of 14-15 seconds will lead to surf of 3-6 feet with sets to along west-facing beaches today, with 3-4 foot waves more likely along south-facing beaches. This NW swell will increase to 3-4 feet Monday, which will increase surf to 4-7 feet for west-facing beaches through Tuesday. Surf on the San Diego Co coast will lead to hazardous swimming conditions and very strong rip currents through Tuesday night.

The combination of high tides and elevated surf will generate minor coastal flooding, with chances for moderate coastal flooding along west-facing beaches where surf will be higher. A Coastal Flood Advisory remains in effect through noon Tuesday for both the San Diego and Orange County coastlines. A Beach Hazards Statement is in effect as well for San Diego County through late Tuesday for elevated surf and strong rip currents.

Reminder, tides mentioned have been corrected to reflect the current trends in actual tide observations.

SKYWARN
Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.



SGX WATCHES/WARNINGS/ADVISORIES
CA...Coastal Flood Advisory until noon PST Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.

Beach Hazards Statement through Tuesday evening for San Diego County Coastal Areas.

PZ...None.