000
FXUS66 KSTO 190958
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
258 AM PDT Thu Sep 19 2019

.SYNOPSIS...
Showers linger across the mountains today, with dry and mild
weather returning through the early weekend. Another system
skims the area Sunday possibly bringing additional chances for
mountain precipitation. Breezy north winds may be seen across the
Valley early next week.

&&

.DISCUSSION...
Radar shows a few showers continuing early this morning across
eastern Shasta County and across the far northern Sierra Nevada
close to the center of the upper low over northeast California.
Elsewhere, skies remain partly to mostly cloudy over the mountains
while clear skies cover much of the Central Valley. Current
temperatures are cooler compared to 24 hours ago across much of
the area and range from the mid 30s in the mountain valleys to the
lower 60s across milder portions of the Central Valley.

Besides some lingering showers in the northern Sierra today as the
low shifts east, dry weather is expected to linger into the
weekend. Northerly winds return through Friday in the Sacramento
Valley, but won`t be overly strong. As ridging rebuilds,
temperatures rise to near average with Valley temperatures ranging
from the mid 80s to around 90 degrees by Saturday.

The next upstream trough is forecast to move into the area on
Sunday bringing a chance of showers to the northern mountains and
northern Sierra Nevada and cooling temperatures a bit.

&&
.EXTENDED DISCUSSION (Monday THROUGH Thursday)...

To commence the week, amplified flow returns to the West Coast as
an elongated trough dives down toward northern California/Nevada.
Details in the eventual placement of this system remain nebulous
as dictated by the forecast spread. While spatial differences have
decreased in recent model cycles, ensemble members still show
enough solutions with an upper low track through northern
California that it cannot be discounted. Ensemble means continue
to favor a more eastward solution over far western Nevada which
will remain the preferred route in the forecast package.

The current ramifications of this solution would be dry, northerly
winds which will reduce relative humidities early next week, thus
elevating wildfire concerns. At this juncture, the gustiest winds
would be on Monday with winds speeds over the Sacramento Valley in
the 20 to 30 mph range. Farther east into the foothills and
Sierra, local gradients favor more of a east-northeasterly flow,
potentially gusty at times. In addition to the winds, high
temperatures will remain warm, especially on Tuesday with readings
likely approaching the mid 90s given 700-mb temperatures in the
12-14C range. There will be a potential cool down later in the
week although it depends on the position of the mentioned upper
low which stalls over the Desert Southwest. In terms of
precipitation, while the threat is low, some isolated showers are
possible Monday over the high Sierra (south of I-80). ~BRO

&&

.AVIATION...

Some residual cloud cover lingers over the southern Cascades and
Sierra with scattered showers continuing into the afternoon.
Otherwise, all TAF sites can expect VRF conditions with mostly
north winds, generally less than 10 knots.  ~BRO

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$