Marine Weather and Tide Forecast for Lake Forest, CA

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

Low clouds and fog spread inland overnight and nearly all of the coastal basin got shrouded. The marine inversion is pretty strong and the stratus deck is pretty solid, suggesting that clearing at the coast might be partial at best today. Some high clouds hint at the upper level low that has begun to form to our north. This will develop today and Thursday over SoCal. That will maintain our deep marine layer, with a similar low cloud coverage the next two nights and mornings. It will also bring a curious chance of showers and thunderstorms in our northern zones, the high desert and San Bernardino Mountains, during the afternoons Thursday and Friday. The moisture and instability in the northeast quadrant of the upper low justify that small chance. The low moves east Friday, but lingering moisture continues that small chance of precip in that area. Temperatures will be a couple degrees lower with less sunshine and more marine influence, especially near the coast, but Friday should be a little warmer. The bigger storm system moves down the coast Saturday. Initially, it will bring strong onshore winds by Saturday afternoon, especially for the mountains, deserts and coastal waters. Top gusts in the top spots through mountain passes should exceed 60 mph. Then comes the precipitation Saturday evening. Winds decrease only a little Sunday while the greatest precipitation appears focused on Sunday. A few thunderstorms should enter the mix Sunday afternoon.
Storm total precip is not impressive, less than 0.50 inch for the top mountain spots. Snow levels will drop rapidly to about 5,000 feet by sunrise Sunday. Several inches of snow are likely at elevations above 7,000 feet. Several shortwaves will rotate within this upper low that cuts off from the jet stream. These will dumbell for a couple days while the moisture gradually decreases.
For most areas, showers will decrease and end Sunday night, but the dumbell effect will continue to provide energy to work with the decreasing moisture to prolong precip chances through Monday especially over the mountains and in southern San Diego County.
Some guidance indicates these chances of mountain showers continuing through Tuesday. Such is the nature of closed lows that cut off from the jet stream, they are content to sit and spin in one place for a while, and tend to overstay their welcome. By midweek, the low should weaken and move east enough to forecast a warming and drying trend.

AVIATION
301530Z
Coasts/Valleys
Low clouds based 1000-1500 feet MSL with tops around 2500 feet MSL have filled most of the coastal basin.
Visibility 2-5 SM for most of the Inland Empire with coastal slopes of the mtns shrouded in FG. Low clouds will clear to the coast by 18- 20z. 25% chance that cigs remain BKN through the afternoon along the San Diego County coast and over nearshore waters. Regardless of whether scattering occurs, low clouds will reinvade coastal sites after 02z this evening and quickly push inland. Bases of around 1000- 1500 ft MSL, will remain around the same height. Vis restrictions possible (2-5 SM) for the Inland Empire and FG where the cloud layer intersects coastal slopes of the mtns. Similar clearing pattern expected Thursday morning with low clouds scattering to the coastline by around 18z. Low clouds may linger at the beaches and over nearshore waters again Thursday afternoon.

Mountains/Deserts...SCT high clouds through Thursday morning.
Isolated thunderstorms after 20z Thursday in the High Desert and San Bernardino County Mtns. If any storms develop, associated vis restrictions and up/downdrafts will be possible.

MARINE
No hazardous marine conditions are expected through Friday. Gusty west to northwest winds will develop over the coastal waters this weekend, with strongest winds Saturday night and Sunday. Peak gusts of 25 to 30 kt expected. Gale force winds are possible, with a 25 percent chance of winds reaching at least 34 kt in the outer coastal waters near San Clemente Island Saturday night into Sunday morning.

BEACHES
Elevated surf of 3 to 6 feet with sets to 7 feet will occur through today. Highest surf occurred on south facing beaches today and will gradually lower tonight into tomorrow. Strong rip currents are expected, especially today.

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

SGX WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement through this evening for Orange County Coastal Areas.

PZ...None.