665
FXUS66 KSTO 142027
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
127 PM PDT Wed Aug 14 2024


.SYNOPSIS...
Near to slightly below normal temperatures persist alongside
periodically breezy diurnal winds heading into the weekend.

&&

.Discussion...
GOES-West visible satellite imagery reveals mostly clear skies
overhead much of interior northern California on this pleasant
summer afternoon. Only indication of clouds would be some cumulus
starting to bubble up around Lassen National Park, extending north
into Oregon. Additionally, some areas of smoke can be observed
in far northern California. Dry conditions are largely forecast
for the region this afternoon, exception being far northern Shasta
County where there is a 10-15% chance of afternoon showers and
thunderstorms. This potential increases traveling north into
Siskiyou and Oregon. Highs this afternoon will land in the
low/mid-90s for most Valley communities, equating to about 2-6 deg
F below mid-August climatology.

Weak upper-level shortwave along the California-Nevada coast will
push inland overnight and into Thursday. This will promote renewed
onshore flow over the coming days. A deeper longwave trough will
dig behind along the 130 W meridian towards the end of the work
week. Temperatures will remain near or slightly below normal as a
result, along with increasing onshore winds by Saturday. While
minimum afternoon relative humidity values are expected to be in
the 25-35% range, will still need to keep a close eye on winds
around active wildfires. Along with the ECMWF Extreme Forecast
Index highlighting for winds, the National Blend of Models is
advertising a 50-70 percent chance of wind gusts exceeding 25 mph
in the central/northern Sacramento Valley on Saturday, including
near the Park Fire. The approaching trough will also increase
thunder chances on Saturday to 15-20 percent for north/west
portions of Shasta and Tehama Counties. // Rowe

&&

.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)...
Upper level trough will remain along the West Coast with
continued periods of onshore breezy winds expected for the second
half of the weekend. Through the middle of next week, cluster
analysis of the ensembles suggests that this trough will remain
quasistationary offshore as it battles with a strengthening, back-
building ridge over Texas. Positioning of these synoptic features
will ultimately determine potential warming in the extended, but
right now, the Climate Prediction Center`s 6-10 day temperature
outlook probabilistically favors below-normal to near-normal
temperatures for the northern third of California, and increased
likelihood of above-normal for southern and eastern California
into the Desert Southwest. // Rowe

&&

.AVIATION...
VFR conditions will prevail for the next 24 hours, except local
MVFR in vicinity of the Park Fire. Surface winds generally below
12 knots, except in the Delta and Sierra Nevada where 15-25 knot
winds. Period of breezy to gusty surface winds at Valley sites
from around 00Z-06Z with surface gusts 20-25 knots possible.

&&

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

&&

$$