Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 230417
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
917 PM PDT Wed Oct 22 2014
A slow moving weather system will bring a roller coaster of
wet/dry/wet weather to end the work week into the weekend.
Thursday will see the first wave impact mainly the coastal range
and northern Sacramento valley. Dry and a rebound in temperatures
Friday. Saturday through Sunday will see widespread precipitation
with breezy winds and isolated thunderstorms Saturday. Saturday
night will bring some high elevation snow to northern Sierra, and
lingering showers Sunday. Next week will continue below average
with periods of precipitation in the north.
A low pressure is spreading precipitation along the northwest
coast and into the far northern interior sections of the state
just to the north and west of Shasta County. Late tonight and
Thursday is when chances increase mainly for areas north of I-80.
This will be the first wave of precipitation to move into
California. Amounts within the valley will be light but this
system may be able to bring about an inch or so of rain to the
As the low deepens on Thursday night into Friday out over the
Pacific a second front forms and becomes a little bit more
oriented north to south on Friday. As this happens a ridge will
develop over Northern California and any remaining precipitation
over the far north will end Friday morning. The system continues
to slow but may reach the coastal range late Friday night.
Saturday is when the front pushes inland given areas the greatest
chance of widespread rain over the entire interior. Winds should
become breezy in the valley and windy across the ridges as the
system passes. Snow levels will remain high above major pass
levels through Saturday but may lower enough to bring some snow
near to levels Saturday night. Instability may become great enough
over the Sacramento valley late Saturday afternoon and evening to
produce some thunderstorms over the Sacramento valley with the
better chances the further north you go.
.Extended Discussion (Sunday through Wednesday)
There is some discrepancies in the models as far as the timing of
the trough exiting northern California Sunday/Sunday night.
Therefore, have lingered showers over northern California through
the day, then shifted to the northern mountains and lowered to
slight chance Sunday night. Monday through Wednesday, the models
show a progressive flow ushering in weak pacific weather systems
across northern California. However, the exact strength and timing
of each wave is uncertain. Therefore, after what looks like a dry
day on Monday, have continued a chance of precipitation Tuesday
and Wednesday. It does appear the best moisture/energy from each
wave will impact locations north of Interstate 80. Temperatures
will remain at to just below normal, with readings in the lower to
Increasing clouds as the cold front approaches, but TAF sites
should remain VFR through overnight. Generally light winds for
the Valley, around 10kt or less. Rain will gradually begin to
spread into the northern Sacramento Valley after 08z. KRDD and
KRBL may have reduced visibilities during showers after 12z, but
expect those sites to hover between MVFR/VFR. Light rain expected
north of I-80 Thursday morning into evening.