Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 220447

945 PM PDT Thu Aug 21 2014

Weak trough over the west coast with northwest flow aloft will
bring dry conditions with a near to a few degrees below normal
temperatures through early next week. High pressure moving inland
over the west coast will bring warming to near or a little above
normal Tuesday into Thursday.


At 02z...temps were running some 4 to 13 deg warmer in the valley
and foothills...which was about the difference in max temps on Thu
as well. Most of the warming came in the Delta influenced area where
max temps were warmer than yesterday by double digits. (Near
persistence over the mountain areas.) We underestimated the warming
for the valley in the evening update last night...on account of the
marine layer on the Ft Ord profiler became squashed around 1500 ft
after 11z this morning...and did not expect that much of a
difference that early in the day. The expected modest Delta Breeze
did kick in as planned this evening...just a little tardy and with
much less cooling than expected.

For Fri...we are expecting more of an influence of the upper trof
moving through the Pac NW and brushing Norcal. Synoptic cooling from
the lowering heights/upper trof passage...and increasing onshore
gradients should lower max temps on Fri. A short wave (vort max)
embedded in the trof is progged to move across the NErn zones Fri
nite with renewed cooling overnight. This feature may also provide
the momentum for a stratus intrusion for the valley as suggested by
the NAM Bufkit forecasts soundings for Sat morning. This will
lead to continued below normal temps...albeit modest warming for
areas north of the I-80 corridor...and near persistence or slight
warming on Sat as heights recover later in the day for areas along
and south of the I-80 corridor.    JHM

.Previous Discussion...

Temperatures are expected to be in the mid 80s to low 90s in the
Valley and 60s and 70s in the mountain Fri afternoon which is a few
degrees below normal for this time of year. Temperatures will be
similar to a little warmer on Saturday and be about the same on
Sunday as Northern California lies between ridge of High pressure
over the Eastern Pacific and a trough over the Western U.S.
Temperatures are expected to be in the mid 80s to mid 90s in the
Valley and low 60s to low 80s in the mountains on Sun which is near
to several degrees below normal for this time of year.

.Extended Discussion (Monday through Thursday)

Ridge of high pressure over the Eastern Pacific builds into
Northern California bringing warmer temperatures into mid-week.
Although the ECMWF is showing a cut off low off of the Northern
California Coast possibly Wednesday and moving inland Thursday
which would increase onshore flow bringing some cooling,
especially to the delta and adjacent valley areas.



Northwest flow aloft over interior NorCal with VFR conditions the
next 24 hours. Southerly wind gusts up to 20 kts through 03Z for
KRDD and KRBL. Local MVFR from stratus/fog in west delta after


.STO Watches/Warnings/Advisories...

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