Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 232139

239 PM PDT Sat May 23 2015

Warmer temperatures with showers and thunderstorms expected this
weekend into next week, mainly over mountains.


.Discussion (Today through Tuesday)...
Low pressure area is currently centered over the Bay Area and will
continue to move south today and tonight through the region. As the
low drops south showers and isolated thunderstorms will continue
to develop with a slight chance that we could see some isolated
activity in the valley. The low is expected to be centered over
the San Joaquin Valley this evening. As it moves south throughout
the evening the shower activity should be reduced.

On Sunday the region will be between high pressure out over the
pacific and low pressure the Rockies. Shower and thunderstorm
chances will continue over the mountains for the afternoon but
they should be located more towards the crest. Skies will be a lot
clearer on Sunday and temperatures will warm up to around normal
for most areas.

On Monday another low pressure area will move over the Pacific
Northwest with the tail end of the trough dipping down into the
far northern part of the state. This will continue the shower and
thunderstorm activity over the mountains and bring a slight chance
for some activity to the far northern end of the central valley.

On Tuesday the low over the Pacific Northwest will move slightly
eastward. This should result in less precipitation over the
interior but still some isolated activity remaining over the


.Extended Discussion (Wednesday through Saturday)

Upper level trough starts shifting east on Wednesday with a
disturbance moving through Northern California. This will bring a
threat of showers and thunderstorms to the mountains again
Wednesday afternoon and evening. Temperatures will be near to a
little above normal with high temperatures in the Valley in the 80s
to around 90 and low 50s to low 70s in the mountains.

Weak ridge over Northern California Thursday and Friday bringing a
little warmer temperatures. Showers and thunderstorms may develop
near the Sierra Crest Thursday afternoon but Friday is expected to
be dry at this time.

Another trough is expected off the west coast on Saturday bringing
increased onshore flow and a little cooler temperatures. Kept the
showers and thunderstorms out for Saturday for now with low
farther offshore. High temperatures are expected to be in the 80s in
the Valley and 50s and 60s in the mountains.



General VFR conditions expected next 24 hours except areas of
MVFR with local IFR conditions over the mountains in the vicinity
of showers and isolated thunderstorms. Local southwesterly wind
gusts up to 30 kts through the Delta.


.STO Watches/Warnings/Advisories...

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