Gusty westerly winds will will quickly become northerly from north to south into Friday. This will bring a period of moderate to locally strong Santa Ana winds to the coastal mountain slopes, foothills, and into the valleys that will last through Sunday. Periods of Santa Ana winds will continue into next week, but are expected to be weaker. Areas of frost are possible in wind sheltered valley locations in San Diego county and the eastern Inland Empire tonight into early Friday morning. Warm days west of the mountains can be expected Friday into early next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Key Points:
*Moderate to locally strong Santa Ana winds are expected tonight into Friday for portions of Orange county, Inland Empire, and coastal slopes of the San Bernardino county mountains, expanding to San Diego county valleys and coastal mountain slopes Friday.
*Santa Ana winds will continue across all valleys, foothills, and coastal mountain slopes into next week. Winds for the first half of next week look weaker than the weekend, with lower confidence in winds for the second half of the week.
*Cold mornings and areas of frost are expected Friday through Sunday for the deserts, mountains, and wind sheltered valleys.
Westerly winds have begun to weaken as of 1 PM and northerly winds have begun to develop on the coastal slopes of the San Bernardino County mountains. A peak wind gust report for the westerly winds is headlined on our weather.gov/sandiego homepage. Peak west gusts overnight and this morning were mainly in the 50 to 65 mph range. Breezy westerly winds were observed in the coastal basin as well with with gusts mainly in the 15 to 20 mph range. West winds in Riverside and San Diego counties will diminish this afternoon/evening and more widespread offshore winds will develop as an inside slider continues to dig south and east into Arizona tonight.
Northerly winds are expected to peak in strength tonight into Friday morning for portions of the Inland Empire, foothills of the Santa Ana and San Bernardino mountains, and portions of inland Orange County. There could be impacts to travel due to strong cross-winds below the Cajon Pass and high profile vehicles should drive with caution Thursday night into Friday morning. Additionally, due to the recent rains the saturated soil may make trees more vulnerable to uprooting (especially on the coastal slopes of the San Bernardino mountains). Peak wind gusts for portions of inland Orange County and the Inland Empire will be 35-45 mph, gusts may be locally to 50 mph below the Cajon Pass. Gusts on the coastal slopes of the San Bernardino and Santa Ana mountains of 45-65 mph, locally higher in wind prone locations near the Cajon Pass.
Winds will become more northeast to east Friday through the weekend as the main driver of the Santa Anas becomes the pressure gradient between Southern California and the Intermountain West. This will spread moderate strength northeast to east Santa Ana winds to the San Diego mountain foothills, locally into the valleys. As the winds become more northeast to east in direction, winds previously mentioned in places north of San Diego county will weaken, but remain elevated. Overall peak gusts of 35-55 mph, locally up to 65 mph, are expected Friday afternoon through Sunday from the valleys to the coastal mountain slopes. The strongest winds will occur on the coastal slopes of the mountains into the foothills and below passes. Periods of Santa Ana winds are expected to continue into next week but current guidance is indicating winds will be weaker for the first half of the week. There remains uncertainty in the wind speeds for the second half.
A very cold airmass will be transported into our area deserts, mountains, and wind sheltered valleys. Coldest conditions are expected tonight into Friday morning for areas west of the mountains, with cold conditions for the deserts and mountains continuing into the weekend. Frost is possible in wind sheltered valley locations overnight tonight, most likely in the Inland Empire south of I-10 and east of I-215 and east of I-15 in San Diego County. Although nights will be chilly for the next few days, a gradual warming trend is expected through next week. By early next week, highs west of the mountains will reach the mid to upper 70s, with highs reaching the 80s for some locations by the end of the week. From Friday onward, marine layer low clouds and fog are expected to be absent from coastal areas due to the dominate offshore flow.
082100z, SCT clouds with bases around 3500-4500 ft MSL are moving through inland SD County and intersecting with the mountain ridges. Clouds continue to scatter out to the mountains through 23z. VFR conditions and clearing skies throughout the lowlands and VFR region-wide by 02z Fri.
Gusty NW winds gusting to 25-35 kts along northeastern portions of the Inland Empire to spread to areas south of the Cajon Pass after 02z Fri and through most of Orange County by 05z tonight as winds turn out of the N/NE. For these lowland areas, periods of gusts 30- 40 kts (locally higher) are possible through Friday afternoon. MOD/STG UDDFS expected for the western/southern foothills of mountains and passes.
In the mountains, 25-40 kt gusts over the Peninsular Range weaken this evening, then NE winds intensify after 03z and periods of gusts of 45-55 kts expected along all southwest facing mountains slopes and ridges through early Friday afternoon. East winds will also intensify to 35-45 kts through the Banning Pass and along SD Co. mtns after 15z Fri.
Gusts 25-30 knots in the outer waters and gusts 20-25 kts within 10 miles of the coast peak this afternoon and decrease by 10 PM this evening.
Additionally, combined seas of 9 to 13 feet with an 8-9 second period (providing locally steep waves) will occur today in the outer waters, peaking this afternoon, and decreasing tonight. Steep seas of 6 to 9 feet are also occurring within 10 miles of the coast today and come down tonight.
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.
Ca, Wind Advisory until 1 PM PST Sunday for Riverside County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains-San Gorgonio Pass near Banning.
Wind Advisory from 8 AM Friday to 1 PM PST Sunday for San Diego County Valleys.
High Wind Warning until 1 PM PST Sunday for San Bernardino County Mountains.
Wind Advisory from 9 PM this evening to 1 PM PST Sunday for Santa Ana Mountains and Foothills.
Wind Advisory from 9 PM this evening to 1 PM PST Saturday 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.
