Cool and unsettled weather pattern continues into next week with occasional showers and mountain snow. Areas of morning frost will be possible beginning Friday through the weekend. Another winter storm next week with breezy winds, widespread Valley rain and significant mountain snow.
One weak shortwave is moving through the region this morning will be followed by a slightly stronger one late this afternoon through the evening. Showers this morning should gradually dissipate in the valley but persist over the western slopes as the first wave exits this morning.
Showers in the mountains should briefly taper for several hours before enhancing in the late afternoon and evening. During the afternoon showers the will likely occur in the valley mainly over the Sacramento Valley and eastern side of the San Joaquin Valley.
Instability is indicated over the area bringing a chance of thunderstorms mainly mid afternoon through the early evening hours. Wind shear is the best from the central Sacramento valley northward where the strongest thunderstorms would likely occur. Half to three quarter inch hail looks possible.
Snow levels today look to be between 4000 to 4500 feet lowering to near 3500 feet after midnight.
On Friday the low will be east of the area and only a few residual showers will remain over the mountains before ending. The morning will be chilly with chances of frost mainly over the Sacramento Valley and foothills. Northerly flow will develop over the area.
On Saturday an inside slider will move into the Great Basin that may produce some showers mainly over the mountains. For the valley it will enhance the northerly flow so would expect breezy conditions during the day.
Wind along with some cloud cover will likely reduce frost chances for a lot of the valley Saturday morning.
Sunday will be a dry day and the coldest morning temperatures are expected. Some north wind over the westside of the Sacramento Valley may limit frost development with the best chances over the eastern side and from around I-80 southward and foothills.
This time of year fruit plants need to get to 30 degrees or lower to cause damage to most fruit trees. Pear, Plum, Peach, Prunes and Cherry trees need to be at 30 degrees for at least 30 minutes to cause damage. The best chances to reach that will be over the foothills.
Extended Discussion (Monday through Thursday)
Longwave troughing continues along the West Coast early next week as cold upper low drops into it Monday and lingers over the area into Wednesday. Widespread precipitation expected with heavy mountain snow.
Breezy to windy conditions Monday night through Tuesday as vertically stacked system digs down the CA coast. Elevated CAPE values depicted in the Central Valley Tuesday afternoon for increased thunderstorm potential.
Latest WPC storm total QPF estimates from Monday through Wednesday night showing around 1 to 2.5 inches of rain in the Central Valley, highest in the Northern Sacramento Valley.
1 to 4 inches of liquid equivalent expected in the foothills and mountains with several feet of new snow expected at pass levels.
Model discrepancies increase midweek as to how quickly upper low ejects, which leads to uncertainties as to how long unsettled weather persists. For now, decreasing threat of showers expected late Wednesday or Thursday.
Below normal high temperatures expected through the extended forecast period.