Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 210500
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1000 PM PDT Sat May 20 2017

.SYNOPSIS...
Dry and very warm the next several days. NorCal`s first triple
digit heat possible early next week over the Northern Sacramento
Valley. A chance of Sierra showers and isolated thunderstorms
Tuesday next week.

&&

.Discussion (Today through Tuesday)...

Short wave along the OR/ID border looks to be too far E to cause
convection on our side of the Sierra Crest on Sun, but will likely
cause an increase in Ely pressure gradients resulting in an increase
in the downslope flow/katabatic wind. Although no significant winds,
they will result in poor to moderate RH improvement Sun nite.  JHM

High pressure will be the dominate feature for Northern California`s
weather through Tuesday. The Valley will see highs again in the 90s
and slight warming over todays highs.

High pressure will continue to build Monday and Tuesday when the
warmest airmass will be over the interior. Dry conditions are
expected for Monday but Tuesday a weak low located near 31N and
130W may help to bring draw some moisture northward along the
crest to bring a chance of thunderstorms. Moisture is limited so
that may change as well but have left a mention in for now.

&&

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)

Models for the long term period starting Wednesday are consistent
in forecasting a pattern change with an upper level disturbance
approaching northern California. Temperatures Wednesday ranging
between 5 and 10 degrees above normal will drop to near normal by
Memorial Day weekend. Onshore flow will return to bring cooling
into the delta influenced locations. Instability associated with
the passing upper level trough will create some chances for
showers and thunderstorms for the mountains, but the valley and
foothills should remain dry from Wednesday through next weekend.

&&

.AVIATION...

VFR conditions the next 24 hours. Southwest winds 10-15 kts in and
near the Delta, otherwise winds less than 10 kts with winds
shifting to the WNW at valley TAF sites.

&&

.STO WATCHES/WARNINGS/ADVISORIES...

None.

&&

$$


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