By Reginald Stanley. Posted December 16, 2019, 3:49 PM.

A cold Santa Ana wind episode has begun over Southern California this week, due to high pressure moving over western Colorado. Winds are expected to strengthen tonight into Tuesday morning.

Following a cold morning, Santa Ana winds picked up across the region Monday, prompting the National Weather Service to issue a Wind Advisory for the valleys and a High Wind Warning for the mountains. In the WeatherCurrents network, Simi Valley has been affected most by the winds, with sustained gusts exceeding 20 mph since Monday morning there. As of 330 PM Monday, Simi Valley has recorded a max gust of 36 mph. In the Inland Empire, WeatherCurrents' stations in Beaumont (Cherry Valley) and Wildomar both recorded max gusts of 31 mph. Other stations with gusts exceeding 20 mph Monday included Riverside (Presidential Park), Riverside (Orangecrest), Perris, Moreno Valley, Murrieta and Temecula.

Fair skies and cool temperatures dominated on Monday, with most valley locations in the 60s. Strengthening winds Monday night through Tuesday morning were expected to be replaced by onshore flow Wednesday and Thursday, as a weak trough passes the region. Weak high pressure is forecast to rebuild Friday and Saturday.