Marine Weather and Tide Forecast for La Presa, CA

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

At 3 AM, there was a patch of dense fog over northern Orange County with another patch of low clouds off the coast of San Diego county.
Otherwise, clear skies were being observed. Weak east to northeast drainage winds are expected to keep most of the low clouds and fog offshore, but local areas of new fog could form due to nocturnal cooling just inland from the coast through the morning hours. Any fog that develops will likely be dense. Another round of fog is likely over portions of the coastal waters and along the immediate coast into Sunday morning.

Weak Santa Ana winds are expected this morning, with peak gusts up to 30 mph. Highs today will be 7 to 15 degrees above normal for inland locations. The pattern changes slightly for Sunday, with the ridging aloft weakening as an area of low pressure moves into the Pacific Northwest. That will result in temperatures 5 to 8 degrees cooler than Saturday.

By Monday the upper level low pressure over the northern United States will dig into the Intermountain West. In addition, a surface high will build over the Great Basin, sparking another round of moderate to locally strong Santa Ana winds. East to northeast winds are expected with peak gusts up to 60 mph on mountain foothills and through passes. Wind gusts of 35 to 45 mph are possible into the valleys. Very dry air is expected in conjunction with the winds, bringing a period of critical fire weather conditions. Winds are expected to peak late Monday night into Tuesday, becoming more localized into Wednesday. Temperatures west of the mountains will generally stay above normal, with Wednesday the warmest day of the week. Thursday will be a few degrees cooler west of the mountains, and with a few degrees of additional warming for the mountains and deserts.

For the end of the week, there remains some uncertainty in the upper level pattern. For Thursday, about 66% of ensemble solutions show an upper level low moving into the Pacific Northwest, with the other solutions indicating some degree of ridging. For Friday and Saturday, the ridging solution becomes the minority with only 13% of solutions showing ridging on Friday and 18% on Saturday. The remainder of solutions show some degree of troughing aloft although there is uncertainty surrounding the strength and position of the trough. Most ensemble solutions are indicating dry conditions through Friday. By Saturday, 30 percent of ensemble solutions are trending wetter. Current forecast has less than 15 percent chance of precipitation for the end of the week and a gradual cooling to near normal temperatures.

AVIATION
071000Z
Coasts
Low clouds have scattered and moved offshore as weak offshore winds developed along the coast, except for one patch in far northern Orange County where vis is 1/2-1 SM. Low clouds redevelop along the coast after about 02Z Sun, moving into the immediate coastal areas after about 06Z. Low confidence in specific impacts to coastal sites. High confidence in reduced vis to at least 3-5 SM in BR again this evening along the coast, with a 40-60% chance for low cigs at KSAN and KSNA after 06Z and 09Z respectively.
If low clouds do move into coastal sites, expecting bases to be 200- 400 ft MSL and vis to be 0-2 SM, with areas of dense FG with vis to 1/8-1/2 SM at times.

Valleys/Mountains/Deserts...Mostly clear skies and VFR prevail through tonight.

MARINE
Very patchy fog with visibility as low as 1/4 nm possible over the waters through this morning, especially for the nearshore waters.
A Marine Weather Statement is in effect and contains more information. Another round of more widespread fog is expected to develop this evening, lasting into Sunday morning. Otherwise, no hazardous marine weather conditions expected through Wednesday.

BEACHES
Patchy dense fog for Orange County beaches north of Newport Beach will continue through this morning, with visibility down to 0-2 miles overnight. More dense fog, likely along most area beaches, redevelops tonight.

FIRE WEATHER
Areas of elevated fire weather conditions expected today due to daytime relative humidity of 10-20% and north to northeast winds gusting to 20-30 mph. In addition, high temperatures will be 7 to 15 degrees above average for inland locations.

Another round of east to northeast Santa Ana winds are expected Monday through Wednesday. Winds are expected to be moderate to locally strong. Winds will peak in strength late Monday night through Tuesday, and gradually fade through Wednesday. Riverside and San Diego County mountain foothills and adjacent inland valleys are expected to have the strongest winds. Gusts around 60 mph through favored passes and on mountain foothills. Gusts of 35-45 mph are expected in parts of the inland valleys. By Tuesday afternoon, relative humidity values should drop near 5-10% for inland areas and 20-30% at the coast. Low humidity, strong winds, and dry fuels will lead to critical fire weather conditions from Monday through Wednesday morning, highest risk on Tuesday.

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

SGX WATCHES/WARNINGS/ADVISORIES
CA...Fire Weather Watch from Monday morning through late Tuesday night for Riverside County Mountains-Including The San Jacinto Ranger District Of The San Bernardino National Forest-San Bernardino County Mountains-Including The Mountain Top And Front Country Ranger Districts Of The San Bernardino National Forest-San Bernardino and Riverside County Valleys -The Inland Empire-San Diego County Inland Valleys-San Diego County Mountains-Including The Palomar And Descanso Ranger Districts of the Cleveland National Forest-San Gorgonio Pass Near Banning-Santa Ana Mountains- Including The Trabuco Ranger District of the Cleveland National Forest.

PZ...None.