October 15, 2017
Summary: Short term, the combination of upper level high pressure building in from the west and the south and an off shore flow which is being created by a much colder air mass is causing the warming. Barometric pressure is also rising over the interior west and this is generating an off shore flow which will peak today before subsiding tonight.
There is still a chance Santa Ana winds over the Kern County mountains could leak downslope and make their way to the valley floor. The greatest risk of this occurring will be near the base of the Tehachapi Mountains from late morning through the afternoon. This downslope effect also causes heating, so I wouldn’t be surprised to see a few 90 plus degree readings today and again Monday.
Beginning Monday, upper level high pressure will be the dominate feature, continuing through Wednesday.
A complex pattern will set up Thursday as a low pressure system which has been meandering well off the central coast for days and days is picked up by a strong trough of low pressure moving through the Pacific Northwest and much of California. This will happen Thursday night through Friday night. High resolution models continue to be bullish on significant precipitation up and down the Sierra, possibly as much as an inch or two with widespread, much lighter rain on the valley floor. Even so, at this point, one quarter inch plus totals are possible north of Kern County with lighter amounts in Kern County.
It appears the best window of opportunity for this whole mess to move inland will be Friday and Friday night though it wouldn’t be a total shock to see showers show up as early as later Thursday night.
The trough will be in Nevada Saturday with lingering showers over the Sierra Nevada. A zonal flow will begin Sunday and last through Wednesday with a westerly flow in the atmosphere moving through California with the main storm track moving back into the Pacific Northwest.
Forecast: Other than occasional cloudiness, it will be mostly clear and warm through Wednesday. Partly cloudy Wednesday night and Thursday. Increasing cloudiness Thursday night with a slight chance of showers. Showers likely Friday and Friday night with a chance of a few showers early Saturday morning. Partly cloudy Saturday afternoon through Sunday.
Temperatures: Highs today and tomorrow will warm into the mid to upper 80s, possibly the lower 90s in Kern County. Lows tonight north of Kern County will be in the mid to upper 40s and the upper 40s to the mid 50s in Kern County. Highs Monday will warm into the upper 80s. Lows Monday night will cool into the upper 40s to the lower 50s north of Kern County and the mid 50s to the lower 60s in Kern County. Highs Tuesday will warm into the upper 80s.