Scientific Forecaster Discussion
fxus66 ksto 141000
Area forecast discussion
National Weather Service Sacramento California
300 am PDT Mon Oct 14 2019
dry and mild weather early this week with temperatures close to
average, then cooler for the second half of the week. A weather
system will bring a chance of showers mid-week.
clear skies cover the region early this morning as the lingering
weak trough edges slowly east. Infrared difference product still
indicating some "heat" from the wildfire near Kirkwood, and with
light easterly gradients and downslope flow expect to see some
smoke drift back into at least the eastern edge of the Sacramento
Valley again this morning. Current temperatures are cooler across
most of the area compared to 24 hours ago and generally range
from the upper 20s in the colder mountain valleys to the 40s to
mid 50s across the Central Valley.
Upstream ridging will move overhead proving more dry and mild
weather the next few days. Some high clouds will spill into norcal
from the north today, but otherwise skies will remain mostly
sunny. Highs will be close to average for mid-October and
overnight lows will be a bit chilly. Depending on fire activity,
there will continue to be some areas of light smoke in the Central
Valley in the mornings.
A stronger low pressure system approaches the West Coast mid-week
that brings a chance of rain to norcal Wednesday night through
early Thursday. Ensembles are in better agreement with the latest
GFS and European model (ecmwf) operational runs lending confidence to forecast of
light quantitative precipitation forecast mainly north of I-80.
Extended discussion (friday through monday)...
a weak short wave embedded within long wave troughing will push
over the northern part of the County Warning Area on Friday. This will bring just
a slight chance for showers for the southern Cascade mountains. A
more robust short wave trough will dig south into the region on
Saturday. This will bring a better chance for showers but activity
is expected to remain over the higher elevations with the best
chances in the north. The track of the trough is an inside slider
type track and it does look like we will see some what breezy
north winds on Sunday as precip chances end. Currently the winds
don't look very impactful and look much weaker than our last
inside slider event. A ridge of high pressure builds in into early
next week. Cool below average temperatures are expected for much
of the extended period but will be returning to near normal early
next week. -Cjm
VFR conditions the next 24 hours at the taf sites. Winds remain
under 12 knots.