May 2, 2019 – Dry and warm today and Friday with an increasing chance of mountain showers or thunderstorms over the weekend and early next week. Mainly dry with well above normal temperatures the second half of next week.
Discussion
Building high pressure aloft over the eastern Pacific and west coast will bring fair skies and well above normal temperatures over the next couple of days. An upper level Pacific low approaches the central coast on Saturday. Diffluent flow aloft ahead of this low will bring a slight chance of showers over the northern Sierra in the afternoon or evening. This mountain shower threat spreads northward on Sunday as the upper low moves inland. Models show enough instability for a mountain thunderstorm threat as well.
Daytime highs cool most areas on Sunday under at least some cloud cover and a cooler airmass. The southern CWA will see the most cooling closest to the low center while the northern portions will remain a little above normal. The upper low is forecast to move into the Great Basin Sunday night bringing a continued threat of mountains going into early next week.
Extended Discussion (Monday through Thursday)
Light shower activity mainly over higher terrain early next week as closed upper low gradually drifts inland. By Tuesday, shower coverage will be limited to areas south of I-80. Showers may persist over higher terrain through the period as guidance shows shortwave energy digging down the West Coast by the middle of next week. Near or slightly cooler than average highs early in the period will be followed by above normal highs by the middle of next week. Breezy north winds could develop by Wednesday/Thursday.