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Area forecast discussion 
National Weather Service Sacramento California
907 am PDT Tuesday Sep 1 2015

Synopsis...
temperatures will cool to well below normal by mid-week as another
weather system moves into the region. Most of the showers are
expected to remain across the far northern portion of the state.
Milder conditions will return for the Labor Day weekend.

&&

Discussion...
mostly clear skies over much of the area this morning with just a
few scattered low marine clouds over the western Delta and some
high clouds spreading into the the northern coastal range and the
northern Sacramento Valley. Temperatures continue to be a few
degrees warmer than yesterday morning for most locations, but an
approaching upper level trough will bring cooler afternoon
temperatures. Highs today will be in the lower 90s across the
valley with sunny skies. The forecast for today is on track, no
changes made.

For this evening and into Wednesday, a strengthening Delta breeze
will bring cooler temperatures into the Delta, southern
Sacramento Valley and northern San Joaquin Valley. The marine
layer may thicken enough to bring some low clouds through the
Delta into the Sacramento Metro area, which could bring a mostly
cloudy period in the early/mid morning.

Models appear to be trending towards a little deeper trough later
in the week, though the 12z GFS has backed off from the 06z run.
We may need to increase chances of precipitation some late
Thursday into Saturday, especially over the northern mountains.
Locations across the area will experience lower temperatures this
week, noticeably cooler Wednesday and continuing below normal
through the rest of the work week. Ek

&&
extended discussion (saturday through tuesday)

Weekend forecast still a bit uncertain as model differences remain
in regards to upper level trough progged to move across the
region. Models have been trending southward with this feature over
past several runs though. The GFS lifts trough east-northeast on Saturday as
it weakens. European model (ecmwf) drops trough a little further south, skirting
norcal Saturday into Sunday. Given southward trend, cannot rule
out a few showers this weekend, mainly across Shasta County, but
low confidence at this point as moisture is limited. Otherwise
dry weather expected elsewhere. More zonal flow moves in for the
start of next week with gradual warming trend. Temperatures will
be a few degrees above normal with 90s in the valley and 70s/80s
across higher elevations for Sunday into the start of the work
week. Ceo

&&

Aviation...

General VFR conditions expected through this evening. Some marine
stratus clouds may spread into the Delta overnight, and could
spread into the southern Sacramento Valley around 12-17z. Winds
generally around 10kt or less, except for a strengthening Delta
breeze after 00z, with gusts to around 25kt. Ek

&&

Sto watches/warnings/advisories...
none.
&&

$$

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