Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 200959
Area Forecast Discussion
National Weather Service Sacramento CA
259 AM PDT Thu Oct 20 2016
Dry through the end of the week with a little above normal
temperatures. A little cooling Saturday with a chance of
precipitation spreading over the forecast area late Sunday
through mid week with below normal temperatures.
High pressure over the southwest U.S. will keep clouds and
precipitation north of the state with just a little warming
expected most areas today. A light northerly surface gradient will
bring light north winds under the ridge. An upper trough digging
into the eastern Pacific will bring a turn to more onshore flow
and a slight cooling on Friday. This cooling trend continues on
Saturday as the upper trough deepens offshore with daytime highs
dropping to below normal. The higher elevations will see
increasing southwest winds. Sunday starts out dry but forecast
models bring a frontal band into northwest California by
afternoon. Models are in fairly good agreement in bringing
precipitation into the northern Sacramento valley by 06z Monday.
Increasing southwest winds and cooler temperatures will also
result as this frontal band moves inland with daytime highs Sunday
about 10 degrees below normal. Light precipitation will spread
over the north end of the state Sunday night mainly north of about
interstate 80. Precipitation amounts will be light with heavier
rainfall having to wait until later in the week.
.EXTENDED DISCUSSION (Monday THROUGH Thursday)
Active weather looks on track for next week as forecast models
continue to be in alignment with an upper level low positioned in
the eastern Pacific. The position of the upper level jet stream
will pool moisture into northern California to bring increased
chances for rain, especially for the northern mountains and
northern Sacramento valley. A general lack of instability will not
allow for thunderstorm development. Snow levels are expected to
remain above 6500 feet, so some mountain passes in the northern
mountains could receive some light snow accumulations next week.
Otherwise, the highest elevations of the mountains could receive
heavier accumulations. High temperatures will generally be about 5
to 10 degrees below normal next week in the 50s and 60s as a
result of the weather system continuing to remain over the west.
VFR conditions next 24 hours. Light northerly winds will prevail
across TAF sites.