000
FXUS66 KSTO 171012
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
312 AM PDT Wed Oct 17 2018

.SYNOPSIS...
Warm and dry this week. Chance of precipitation by the middle of
next week.

&&

.DISCUSSION...
Clear skies continue across interior NorCal early this morning.
Pressure gradients have slackened a bit further compared to 24
hours ago (MFR-SAC is below 4 mbs while the RNO-SAC is under 6
mbs), and overall wind gusts have decreased as a result. Still
seeing a few spots in the northern Sierra and foothills with gusts
above 30 mph.

Dry weather with mild days and cool nights will continue through
the remainder of the week as ridging over the eastern Pacific
shifts over the PacNW and a weak trough lingers over SoCal.
Lighter winds are expected as gradients relax further.

&&

.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)
Weak upper low forecast to push across California on Sunday
bringing minimal impacts to norcal weather. Any precipitation
associated with this low should remain south of the forecast area
and even with a slight cooling, daytime highs are expected to
remain slightly above normal. Upper level Rex block pattern shifts
into the Great Basin on Monday bringing slightly cooler
temperatures but more importantly, the start of a transition to a
cooler and possibly wetter weather pattern. Models are in fairly
good agreement in pushing a shortwave trough into the Pacific
Northwest and Norcal on Tuesday. Models do differ a bit on depth
of this system but currently keep precipitation threat over the
northern portions of the CWA. Backed off somewhat on expanse of
precipitation chances using latest NBM as a guide. Even with the
cooling effect and cloud cover, current forecasts still keep
daytime highs Tuesday slightly above normal. Another shortwave
trough is forecast to move into the Pacific Northwest next
Wednesday for another degree or two of cooling but this still
looks to be a far northern California precipitation producer.

&&

.AVIATION...
VFR conditions all TAF sites next 24 hours. Winds generally below
12 knots except gusts to 15 knots down Sierra Nevada canyons
during the early morning hours.

&&

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

&&

$$