Scientific Forecaster Discussion
fxus66 ksto 131050
Area forecast discussion
National Weather Service Sacramento California
250 am PST Wed Nov 13 2019
dry weather pattern continues this week with a cooling trend.
Warmer this weekend with highs returning to well above average.
partly cloudy skies cover the region early this morning. Winds are
light across most of the area except for some local lingering east
winds of 15-25 mph over the northern Sierra foothills. Current
temperatures range from the mid 20s in the mountain valleys to the
lower to mid 60s across the milder foothill thermal belts. Central
Valley locales are mainly in the mid 40s to lower 50s.
The persistent West Coast ridge will shift east over the next
couple of days as the upper trough off the coast approaches and
then moves onshore later Thursday into Friday. Lots of mid and
high level cloudiness will spread across the region (even more
than what we've seen over the past few days), and combined with
synoptic cooling from weakening high pressure, will lead to cooler
temperatures through the end of the work week (though still above
average for mid-november).
Pattern repeats itself beginning this weekend as Rex block
redevelops along the West Coast leading to a return of warmer
temperatures and likely some daily record highs in jeopardy.
Extended discussion (sunday through wednesday)...
a powerful upper ridge will be in place to commence the weekend
with 500-mb height anomalies in the 1.5 to 2 Standard deviation
range. Projected heights may reach 590-dm on Sunday which is quite
impressive for the time of year. The accompanying 850-mb
temperatures of 18c would support highs well in the 80s in a well
mixed atmosphere. However, such an environment is often
unattainable deeper into the cool season so valley highs from the
mid 70s to low 80s are more likely. Relative to climatology, this
is roughly 10 to 20 degrees above average. With a daily record
high in Redding of 83 degrees (dating back to 1893), would not be
surprised to see this either tied or broken. Well above average
readings will continue into Monday given the ridge lingers yet
From Tuesday into later in the week, the upper ridge will finally
have advanced into The Rockies. A seasonably strong trough enters
the picture while accelerating through the Pacific northwest early
Tuesday. While a few ensemble members support the trough taking a
farther west track bringing some scattered showers to the region,
a vast majority carry the system through the central Great Basin
instead. The latter scenario would favor an uptick in northerly
gradients which lowers humidities and enhances wind fields. Given
this trough remains nearly a week out, it will need to be closely
monitored for any notable impacts. In the meanwhile, high
temperatures from Tuesday Onward should be noticeably cooler, but
still roughly 3 to 6 degrees above average. ~Bro
VFR conditions the next 24 hours except local MVFR visibilities
from ksac southward 12z-17z. Winds generally below 10 knots.