Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 210401
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
901 PM PDT TUE SEP 20 2016

.SYNOPSIS...
Cooling trend with a slight chance of Mountain showers and
thunderstorms Wednesday and Thursday. Warming and drying trend by
the weekend.

&&

.Discussion...
A trough of low pressure over the Pacific Northwest will continue
to dig south over the next two days and continue producing a
cooling trend. The delta breeze has increased this evening between
15 and 25 kts and the marine layer has reformed but at this time
remains low at around 1200 feet. Temperatures are generally
running 5 to 10 degrees cooler this evening throughout the
interior.

Models continue to shower a little bit of moisture from Hurricane
Paine making its way far enough northward late tonight and
Wednesday morning from around I-80 southward. This may bring some
a few showers to parts of the west slopes during the AM hours.
Temperatures will continue to cool into the upper 70s to mid 80s
for the valley to the 60s to lower 70s for the mountains.

As the trough continues to deepen Wednesday night into Thursday
and more cooling is expected. The through will bring a chance of
showers mainly around the central part of the low starting over
Shasta County Wednesday evening then brining chances into Plumas
County later at night. The atmosphere looks unstable enough that
some isolated thunderstorms can not be ruled out for those areas.

As the low moves into Nevada on Thursday some wrap around moisture
may bring some showers along the crest. Snow levels will fall
between 6000 and 7500 feet as the low moves through but not much
in the way of accumulation is expected. Breezy northerly flow
will develop on Thursday within the valley. Thursday is expected
to be the coolest day of the week with highs in the 70s for the
valley to the 50s to mid 60s in the mountains.

Dry warmer with breezy north winds is expected for Friday. This
will be the start of a warming trend.

.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)

Warm weather and dry conditions will return to NorCal as an upper
level ridge of high pressure strengthens over the eastern Pacific
this coming weekend. High temperatures will return to about 5 to
10 degrees above normal this weekend through the beginning of next
week. Forecast models are in good agreement to having the high
pressure system dominating the weather for NorCal at least
through the middle of next week.

&&

.AVIATION...

Mainly VFR conditions continue the next 24 hours with lcl MVFR
conditions over the mountains after 12Z. Gusty winds through the
delta with gusts up to 30 kts and over ridgetops.

&&

.STO Watches/Warnings/Advisories...
Red Flag Warning from 11 AM to 8 PM PDT Wednesday for Northern
Sierra Including Lassen NP and Plumas and Lassen NF/S West of
the Sierra Crest (West of Evans Peak-Grizzly Peak-Beckworth
Peak).

&&

$$



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