Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 262229

Area Forecast Discussion
National Weather Service Sacramento CA
329 PM PDT MON SEP 26 2016


An upper level ridge will remain in place through Tuesday, which
will keep above normal temperatures across the region. A cool down
is expected as an upper level trough moves into northern
California for the rest of the week and into the weekend.


.DISCUSSION (Today through Thursday)...

Water vapor imagery and model analysis continued to show a strong
upper level high pressure system positioned over the Great Basin,
which kept warm and dry air in place for northern California.
Clear skies with temperatures in the upper 80s/lower 90s were
prevalent during the early afternoon hours across the valley, and
temperatures in the upper 70s for higher elevations.

Models are in good agreement to keeping the upper level ridge in
place across northern California through Tuesday, and as a result,
high temperatures between 10 and 15 degrees above normal. The
ridge will break down starting Wednesday as an upper level low
pressure system begins to deepen off the coast of the Pacific
Northwest. This trough feature will continue to deepen late into
the work week and bring slightly cooler high temperatures
Wednesday and Thursday. No significant chances for precipitation
are expected at this time.


The main feature during the extended period will be a trough of
low pressure deepening over the forecast area, with embedded
disturbances in the upper flow. The upper trough should result in
cooler temperatures over interior Northern CA. Temperatures
could be 5 to 12 degrees below normal this weekend, with Valley
highs mainly in the 70s. There are still some model differences
regarding the evolution of this system after the Sunday period,
but have kept precipitation chances mainly over the northern



VFR conditions over interior NorCal next 24 hours. Light winds
will prevail across TAF sites.

.STO Watches/Warnings/Advisories...

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