textproduct: San Diego

SYNOPSIS

Strong westerly winds in the mountains and deserts today will be followed by a wind shift to northerly winds in San Bernardino County and the Inland Empire late today and tonight. High pressure and Santa Ana winds will bring warmer weather, especially west of the mountains through the middle of next week. Northeast winds in foothills and parts of valleys will be strong at times.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

One low pressure trough has exited, and the next one is flying into SoCal from the northwest today. This will boost westerly winds this morning, especially on desert slopes of mountains and into deserts. Gusts 45-65 mph are expected in these areas. This wind pattern will abruptly switch to northerly winds as this inside slider system dives into Arizona late today. With the switch to offshore, some populated zones west of the mountains will become part of the advisory for these offshore Santa Ana winds. High pressure aloft will amplify and strengthen along the West Coast Friday into next week. This will bring a warming trend, although initially Friday it will be quite cool. A dry and cold air mass over the region and clear skies will allow for some cold nights in the SoCal interior through Saturday morning, especially where winds calm down. We lose some of the upper support for offshore winds Friday and Saturday, but the offshore pressure gradient actually tightens this weekend. Areas of strong northeast winds will continue in the usual foothill and inland valley areas, but also at times venturing into coastal areas. There's no end in sight for this offshore Santa Ana pattern, at least for the next week. Temperatures will start to rise into the 70s at lower elevations by Saturday, and increase each day through Wednesday, when upper 70s and low 80s will be common. Fire potential will rise with the winds and temperatures, but fuel moistures remain above critical levels. However, many days of this prolonged offshore flow will certainly bring down fuel moisture. Skies will remain mostly clear Friday and beyond.

AVIATION

081630Z...SCT-BKN low clouds with bases around 2000-3000 ft MSL and tops to 5000-6000 ft MSL are moving through most of the coastal basin and intersecting mountain terrain. Clouds scatter out slowly through 23z from northwest (Orange County) to southeast (SD Co. mtns). VFR conditions and clear skies prevail in areas where clouds scatter out.

Breezy onshore flow expected across the coasts and valleys today, with northwest gusts 20-25 kts and locally to 30 kts expected from through 23z this afternoon. Winds remain elevated in the Inland Empire this evening as winds switch direction out of the N/NE. These winds increase after 02z Fri, especially south of the Cajon Pass and eventually spreading through most of Orange County by 05z Fri. For these lowland areas, periods of gusts 30-40 kts are possible through Friday morning. MOD/STG UDDFS expected for the western/southern foothills of mountains after 06z Fri.

Mountains/desert slopes will experience even stronger gusts through the period. Through 00z Fri, west winds with gusts 40-50 kts expected for mountain ridges and east facing desert slopes of the Peninsular Range. After 03z Fri, NE winds intensity and periods of gusts of 45-55 kts expected along all southwest facing mountains slopes and ridges through Friday morning. East winds will also intensify to 30-40 kts through the Banning Pass and along SD Co. mtns after 15z Fri.

MARINE

Gusts this morning increasing to 25-30 knots in the outer waters and gusts 20-25 kts within 10 miles of the coast, peaking in the afternoon and decreasing by 10 PM this evening.

Additionally, combined seas of 8 to 11 feet with an 8-9 second period (providing locally steep waves) will occur today in the outer waters, peaking in the afternoon, and decreasing tonight. Seas briefly reach 6 to 9 feet within 10 miles of the coast today.

A Small Craft Advisory remains in effect through 10 PM this evening contains more details. After today, no hazardous marine conditions expected through this weekend.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Wind Advisory until 1 PM PST Saturday for San Bernardino and Riverside County Valleys-The Inland Empire.

High Wind Warning until 1 PM PST Saturday for San Bernardino County Mountains.

Wind Advisory until 1 PM PST this afternoon for Apple and Lucerne Valleys-Coachella Valley-Riverside County Mountains- San Diego County Deserts-San Diego County Mountains-San Gorgonio Pass near Banning.

Wind Advisory from 9 PM this evening to 1 PM PST Saturday for Santa Ana Mountains and Foothills.

Wind Advisory from 9 PM this evening to 1 PM PST Friday for Orange County Inland Areas.

PZ...Small Craft Advisory until 10 PM PST this evening for Coastal Waters from San Mateo Point to the Mexican Border and out to 10 nm-Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.