Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 210424
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
924 PM PDT Mon Oct 20 2014
Frontal system will continue cooler temperatures and
precipitation chances through tonight...mainly for the mountains.
An elongated frontal system impacts northern CA with potential
showers from Wednesday night into the weekend.
.Short Term Discussion (Tonight through Thursday)...
The central core of the low pressure system continues to push
inland this evening. Showers with isolated thunderstorms will
continue for a couple more hours before gradually dissipating
after midnight. The earlier thunderstorms over Shasta County
brought some strong thunderstorms the produced some heavy
rainfall and hail up to dime size. One gauge near Shasta Dam
recorded half and inch in less than an hour.
The low will move into Nevada overnight and zonal dry flow will
set up behind the front for Tuesday. A low pressure area in the
gulf of Alaska will start to spread precipitation along the
northwest coast late Wednesday and into the far northern interior
sections of the state Wednesday night into Thursday. Late
Wednesday night and Thursday is when chances increase mainly for
areas north of I-80.
As the low deepens on Thursday night into Friday the front begins
to shift and become a little bit more oriented north to south.
This may dry out the interior sections while the coastal range may
continue to see some precipitation. Friday night is when the front
pushes inland given the greatest chance of widespread rain over the
entire interior along with some higher elevation snow.
.Extended Discussion (Friday through Monday)
A cooler and unsettled weather pattern will continue the end of
the week through the weekend. A low in the gulf of Alaska will
slowly move south and send disturbances inland over northern
California and the Pacific Northwest. The first such weather
system will move over northwest CA early Thursday and spread light
showers across the northern Sacramento valley by Thursday
afternoon/evening. By the weekend, the main weather system will
move inland over Oregon and Washington and spread more showers
into northern California. There is some discrepancy in the models
as to how much moisture/energy make it into the valley and how
fast the system moves through. At this time, have continued the
chance of showers in the forecast through the weekend. There`s
also a possibility of light snow accumulations Saturday night in
the northern Sierra. Progressive pattern looks to continue into
early next week, but timing and strength of systems is uncertain
at this time.
Scattered showers over the mountains will gradually taper off
late tonight. VFR in the valley with areas of MVFR cigs and vsbys
in the mountains through 12z with LCL IFR conditions. Conditions
improving after 12z.