Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 240519
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1015 PM PDT Sun Apr 23 2017

.SYNOPSIS...
Several Pacific storms move through bringing cooler temperatures
with some light precipitation tonight into Thursday.

&&
.DISCUSSION (Today through Wednesday)...

A slightly stronger disturbance will move through the interior late
tonight and Monday. This will bring some precipitation to the
interior starting late in the evening and lasting through Monday.
Clouds should continue to be on the increase ahead of the
precipitation. Generally a trace to less than a tenth of an inch of
rainfall is expected within the valley to a quarter to three
quarters of an inch of rain for the foothills and mountains with the
higher totals over the north. Snow levels will be high enough at
times to limit the amount of snowfall below major pass levels to an
inch or two. Radar beginning to detect an area of light rain moving
onto the coast from Ft Bragg Nwd as baroclinic leaf cloud hits the
coast. Water vapor imagery shows the main impulse near 44N/130W and
this feature is progged to move ESEwd across Norcal overnite and into
Mon morning. By 18z Mon, it is forecast to be in NV. Thus the bulk
of the precip should correlate reasonably well with this feature as
the colder cloud tops from the leaf should move across the area with
this feature. Then cloud tops should warm over Norcal, although
moist NWly flow should keep cloudy skies and scattered light showers
going into Mon afternoon. Higher resolution QPF/REF progs show some
rather hit/miss showers with some higher REFs in Tehama/Placer
counties which could mean a chance of isolated and brief thunder as
well, around 5 pm Mon.    /JHM

Moist zonal flow will continue to stream clouds over the region
through Wednesday. A weaker disturbance on Tuesday may bring some
more light amounts of precipitation to the interior. Most of the
precipitation will be over the mountains north of I-80 but a few
showers may move over the Northern Sacramento Valley at times. A
third weak disturbance will move through late Tuesday night and
Wednesday and bring a slightly better chance at getting showers
down to the Sacramento region within the valley. Snow levels will
be high and snow will be a non factor with both weak systems.

Temperatures on Monday look to be the coolest this week with
gradual warming through midweek back to near normal.

$$
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)

High pressure continues to build over the eastern Pacific causing
a continued increase of temperatures through the weekend. A brief
system could brush through the far northern Sacramento valley and
northern Sierra crest Thursday, though very little accumulations
are currently expected. Otherwise, dry weather expected for the
rest of interior NorCal with temperatures rising to near or higher
than normal by Saturday. The synoptic setup with this upper level
ridging could bring gusty northerly winds Thursday evening
through Saturday. Models have been trending toward higher wind
speeds than previous runs, and current model runs indicate winds
could reach wind advisory criteria Friday, especially in the
northern San Joaquin valley. However, this far in advance will
have to continue keeping an eye on the model trends.

&&

.AVIATION...

VFR conditions for the next 24 hours. A weather system will bring
lower ceilings and light precipitation after 6Z Monday. Local MVFR
ceilings possible with precipitation and over the Sierra crest
overnight.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$



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