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Northern CA Forecast Discussion
FXUS66 KSTO 230920
Area Forecast Discussion
National Weather Service Sacramento CA
220 AM PDT Thu Mar 23 2023
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.
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
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`s need to be at 30 degrees for at least 30 minutes to cause
damage. The best chances to reach that will be over the
(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.