May 17, 2019
Summary: It is a relatively quiet afternoon weather-wise over central California. There are quite a few cumulous cloud formations, especially in the south valley, where upsloping is occurring against the Kern County mountains and the extreme southern Sierra Nevada. Over the Pacific Ocean, a complex weather system is developing in the southern Gulf of Alaska. It will drive southeastward into northern California as early as midmorning Saturday. There will be an increasing chance of showers from mainly Fresno County north Saturday afternoon with precipitation spreading over the remainder of the valley Saturday evening ahead of an advancing cold front.
That front will result in periods of rain into early Sunday morning. Most of the models this afternoon place the center of circulation of a cold upper low over the northern two-thirds of California during the day Sunday. These models continue to favor numerous showers and isolated to scattered thunderstorms Saturday, especially during the afternoon and evening hours. The main body of low pressure will not slide east of the Sierra Nevada until the late evening hours Sunday.
The potential for significant rain over the entire valley is high with this system. Half-inch plus totals would not be a surprise at all just about anywhere in the valley with the heaviest amounts in the center and east side as we should see somewhat of a rain shadow develop along the west side.
Models are trying to come into some kind of agreement for the Monday through Wednesday time frame. It still appears Monday and more especially Tuesday will see unsettled weather with a small chance of showers Monday and a somewhat higher risk Tuesday and Tuesday night. some models show the main body of low pressure moving over the Desert Southwest by Wednesday afternoon. This would be much less favorable for showers with the possible exception of the Sierra Nevada.
There will be a daily chance of showers over the higher elevations of the sierra Nevada Thursday and Friday, but in all likelihood the valley floor will remain dry. Even though next weekend and beyond don’t show indicators for the extremely active pattern we’re experiencing, the two week model which goes out through the last day of the month is still indicating a higher than normal risk of precipitation during this period with below average temperatures continuing.
Forecast: partly cloudy tonight. Increasing cloudiness Saturday morning. A chance of showers mainly north of Kern County Saturday afternoon. Periods of showers with a chance of thunderstorms Saturday night. periods of showers continuing Sunday into the late evening hours with a chance of isolated to even scattered thunderstorms, especially Sunday afternoon and evening. A slight chance of showers Monday with a greater risk of showers late Monday night through Tuesday night. becoming partly cloudy Wednesday and Wednesday night. mostly clear Thursday through Friday.
Temperatures: Lows tonight will drop into the mid 40s to the lower 50s. Highs Saturday will warm into the low to mid 70s. Lows Saturday night will cool into the low to mid 50s. highs Sunday will warm only into the mid to upper 60s.