Alta Sierra, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

831
FXUS66 KSTO 160930
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
230 AM PDT Mon Sep 16 2024

.Synopsis...
Cooler unsettled weather thru mid-week with periods of showers
and isolated thunderstorms. Dry and warmer weather returns late in
the week into next weekend.

&&

.Discussion...
557 DM upper low centered just NE of KEDU this morning is progged
to continue to dig SSE today is it slowly begins to fill. Best
chances for showers looks to be in the vicinity of low center and
with wrap around moisture over the mountains. Isolated
thunderstorms also possible over the mountains today in areas of
higher CAPE. Snow levels remain at or above pass levels with local
light accumulation`s possible in stronger cells. System has
ushered in cooler air, and high temps today forecast to be
upwards of 20+ degrees below normal. NBM predicting low to mid 70s
for the Central Valley with 40s to 60s for the mountains and
foothills.

Primary upper low continues to fill tonight as it heads to SoCal
while secondary low develops over the Great Basin. Lingering
showers possible overnight, mainly over the Sierra Nevada with
snow levels remaining at or above pass levels.

Drier weather expected Tuesday with slight warming as weak short
wave upper ridging moves through. Another short wave trough then
progged to drop into West Coast long wave Tuesday night into
Wednesday. This will bring another round of unsettled weather to
interior NorCal. POPs increase from N to S Tuesday night with
widespread threat of showers over the CWA Wednesday. Best
instabilities depicted over the foothills and mountains for
potential thunderstorms. This wave appears not as cold aloft as
the system moving through today, and 5H cold core remains
offshore through Wednesday. Thus bulk of precip in mountains
expected to be liquid as snow levels remain well above pass
levels.

Upper low is progged to continue to dig south along the CA coast
to near Point Conception by 12z Thu, then track eastward across
CA. Precip threat continues over the Sierra Nevada Thursday while
remainder of the CWA sees fair weather with warming as EPAC upper
ridging begins to build inland. High temperatures Thursday climb
back into the 80s for the Central Valley.

&&

.EXTENDED DISCUSSION (Friday THROUGH Monday)...
Dry weather expected through the extended forecast period as EPAC
high extends inland over NorCal. AMS slowly warms into the
weekend with high temperatures returning to near normal Sunday
into Monday.

&&

.AVIATION...
In Central Vly, isold MVFR conditions possible at times in shra
til 03z Tue, otherwise mainly VFR next 24 hrs. Sfc wind generally
below 12 kts.

Over fthls and mtns, areas MVFR/IFR possible next 24 hrs with
trrn obscd. Isold tsra possible thru 03z Tue. Snow levels abv 7k
ft. Lcl Wly sfc wind gusts to 20 kts possible over hyr trrn thru
00z Tue.

&&

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

&&

$$