Friday evening weather forecast – Nov. 19
A warming trend is expected for most of the forecast area on Saturday then Santa Ana conditions will arrive for Sunday and Monday. Gusty and dry northeast winds will result in critical fire weather conditions in our mountains and throughout Ventura County. Cooler conditions are forecast for Tuesday and Wednesday as a weak weather system moves over the region, but offshore flow is expected to redevelop on Thanksgiving Day.
Fairly quiet weather in store for the area through Saturday. Mid and high level clouds will at least create some filtered sunshine for the remainder of the afternoon with a little thicker coverage overnight Friday night and Saturday morning. Expect a return of low clouds and patchy fog tonight and early tomorrow morning along the coastal zones and some nearby valleys, also extending into the San Luis Obispo County interior.
Mid level west to northwest flow increases tonight in advance of a weak trough that passes through Saturday morning. This will produce some breezy conditions. Saturday will see a gradual switch to offshore flow by the evening which will help to warm the coastal and nearby valley zones Saturday. Another trough passes from our northwest on Sunday night while surface high pressure builds over the Western Great Basin. This will increase the offshore pressure gradients and start a 24 to 30 hour period of moderate to isolated strong Santa Ana winds through Ventura County. Wind gusts are expected to be between 35 and 55 mph with isolated 60 mph values in the more wind prone areas. Wind speeds will sustain through Sunday and Sunday evening with only slight weakening, then pick up again slightly on Sunday night. Offshore gradients change little by Monday morning, however the upper level flow pattern becomes less favorable for gusty northeast winds as a closed upper low about 500 miles offshore socal opens up and moves northeast to produce southwest flow aloft Monday morning and through the day. This upper flow also pulls quite a bit of mid and high level moisture from the tropics to make for a pretty cloudy day on Monday. The northeast winds therefore weaken through the afternoon and coastal areas will get a weak sea breeze by later in the afternoon. This shouldn't be a very warm Santa Ana event, especially compared to what we've experienced with the last few Santa Ana events when we had highs in the 90s in some locations. This is mainly due to the cooler low level temperatures off the surface and also hindered by the cloudiness expected on Monday. Expect highs in the upper 70s to low 80s
Critical fire weather is expected in the mountains and throughout Ventura County. A red flag warning is in palce for Ventura County from Sunday 9AM through Monday 3PM as gusty winds drop humidity and create dangerous fire conditions. A fire weather watch is in place Sunday for the mountains of Santa Babrara and San Luis Obispo Counties.
A deep upper low moving in on Tuesday will cool temperatures right back down. For now Thanksgiving looks to be comfortable with seasonable conditions.
