Area Forecast Discussion
Issued by NWS Sacramento, CA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

FXUS66 KSTO 241709

1009 AM PDT Fri Oct 24 2014

Warmer conditions today as a ridge of high pressure builds
over the western U.S. A weather system will bring rain, mountain
snow and windy conditions Saturday with showers Sunday. A brief
break Monday will be followed by a chance of rain over areas north
of Sacramento Tuesday and Wednesday. This precip threat will drop
southward bringing rain or mountain snow over much of NORCAL for
the end of the next week.

Upper level trough in the Eastern Pacific with a weak ridge over
Northern California today. Areas of fog developed around Chico and
south to east of Modesto this morning. Fog became dense in some
locations this morning including Sacramento and Marysville so
dense fog advisory is out until 10 am as Visibilities are gradually
improving this morning. Temperatures this afternoon will be warmer
than yesterday with mostly sunny skies and a little warmer
airmass. Although temperatures will be similar to yesterday around
Sacramento  to Stockton with fog and low clouds this morning.

The trough approaches the coast tonight increasing the clouds and
spreading a threat of precipitation into the Coastal range and
Shasta County around midnight and spread southeast across interior
northern California Saturday. Southerly winds will increase late
tonight into Saturday as the cold front and trough move inland.
This will bring breezy and gust winds with gusts to around 40 mph
in the Valley and up to 60 mph in the mountains so holiday
decorations should be secured. Precipitation amounts are expected
to be around an inch in the mountains except Shasta County
mountains will see more due to good orographics. About a quarter
to half an inch in the Northern Sacramento Valley to less than a
tenth of inch in the northern San Joaquin Valley is expected. Some
instability Saturday afternoon and evening for threat of
thunderstorms. Winds should decrease Saturday evening and
precipitation decreasing Sunday morning. Snow levels will start
between 8000 and 9000 ft and drop to around 6000 to 7000 feet by
Sunday morning. Several inches of snow are possible around Mount
Lassen but only around a couple inches expected around the Sierra
passes. Precipitation will taper off on Sunday with showers mainly
lingering over the Shasta County and down the Sierra. Monday will
be a drier and warmer day with ridge building into the area as
trough shifts east.

.Extended Discussion (Tuesday through Friday)

Flat high pressure over the southwest U.S will keep at least the
southern half of the forecast area dry Tuesday and Wednesday. The
northern portions of the forecast area will see a continued threat
of light rain. Daytime high temperatures under mainly cloudy skies
are expected to come in a few to several degrees below normal.
Another cool low pressure system dropping out of the Gulf of
Alaska will bring precipitation chances southward on Thursday and
Friday. Models still not showing real good consistency during this
7 to 8 day time frame however both run to run and model to model so
forecast confidence not high during this time frame.



Lingering rainfall this morning is associated with a frontal
boundary currently located along the northern coastal range and
northern mountains. This is shifting north, with dry conditions to
the south. Areas of dense fog around KCIC to KSCK this morning
including Sacramento. Visibilities should increase aft 17z with
VFR/MVFR conditions expected this afternoon. High thin clouds
with winds from the south between 10-15 mph in the afternoon. A
system spreads in late tonight bringing chances of rain and
increasing winds.


.STO Watches/Warnings/Advisories...

$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.