Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 272230
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
330 PM PDT FRI MAY 27 2016


.SYNOPSIS...
A few afternoon showers or thunderstorms over the northern Sierra
through Monday. Very warm weather expected through the middle of
next week. Breezy north winds later today and Saturday.

&&

.DISCUSSION...
Northern California remains under northwest flow aloft between
high pressure over the eastern Pacific and an upper trough over
the Pacific Northwest. Skies are mostly clear across most of the
region, and even Sierra cumulus development is a fair bit less
than the past few days. Pressure gradients have tightened the last
several hours, and breezy northerly winds have developed along the
northern and western Sacramento Valley. Temperatures are now
running 2 to 8 degrees warmer than yesterday, and are expected to
peak around 90 degrees across the Valley.

Heights and thicknesses will increase a bit the next several days
as th eastern Pacific ridge builds eastward. Slight warming is
expected accordingly through the weekend, with peak temperatures
expected on Memorial Day when the Valley could reach the mid to
upper 90s.

Isolated showers or thunderstorms will be possible over the higher
Sierra the next several days. A weak upper low will form over
Central and Southern California on Saturday, which could increase
coverage of thunderstorms. Otherwise, forcing and instability will
be relatively limited.

Dang

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)


The forecast concern during this period continues to be the heat
that will affect northern California with above normal temperatures
through the end of next week. A broad upper level high pressure
system will continue to build into the west from the eastern
Pacific, which will bring widespread temperatures in the mid to
upper 90s across the valley Tuesday. Higher elevations will
likely see the 60s and 70s.

Model forecast solutions start to diverge Wednesday.  The ECMWF has
a higher amplitude trough of low pressure moving into the eastern
Pacific, which could bring chances for scattered showers and
thunderstorms to higher elevations in northern California, but
the GFS solution advertises a shortwave trough of low pressure
moving across the Pacific northwest with a ridge of high pressure
still in position over the forecast area. For now, left the
forecast trending towards the GFS solution due to little variation
from previous run compared to the ECMWF with more variability from
the previous forecast period.

In both forecast scenarios, temperatures will cool slightly
towards the end of next week as a trough of low pressure moves
towards northern California, however temperatures will still be
above normal for the forecast area. Chances for precipitation next
week are expected to be minimal.
&&

.AVIATION...



VFR conditions are expected at the terminals for the next 24
hours. Light wind shifts are expected for TAF locations near
Sacramento overnight. Periodic mid to late morning gusts are
possible Saturday for the terminals, and will last through the
afternoon hours.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$


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