Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 251231
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
531 AM PDT Sat Oct 25 2014

.Synopsis...
Strong winds and precipitation moves in today with a frontal
system. Thunderstorms today with heavy rain, accumulating small
hail, and maybe even isolated tornadoes. Snow levels will come
down to below Sierra passes tonight. A brief break late Sunday
into Monday will be followed by potentially more wet weather mid
next week and again late week.

&&

A frontal rain band is reaching the Coastal Range as of 500am with
the cold front near the coast. The front is moving about 20 mph
and rain should begin over Redding and Red Bluff between 530 and
600am. Southerly winds have dramatically increased this morning.
We have added wind advisories to the Coastal Range and lower
foothills of Plumas and Shasta counties, to go with the wind
advisory already in place over the Sacramento Valley and western
Delta. We have also issued a High Wind Warning for the higher
Sierra into tonight. As the front approaches and passes later this
morning and afternoon, winds will continue to increase to 15 to 30
mph with gusts 40 to 50 mph in the Valley and 50 to 90 mph over
higher terrain. This could cause some trees and even some power
poles to come down, potential causing some localized power
outages. Remember that leaves are still on the trees, so these
stronger winds can potentially produce more damage to trees. Winds
should be decreasing this evening.

Shasta county mountains could see up to 2 inches of precipitation
by Sunday morning with good orographics with the southerly winds.
Snow levels will be around 8000 ft this morning and drop down to
around 5300 to 6500 ft on Sunday morning. Snow accumulations up to
10 inches are possible on Mt Lassen and up to 4 inches possible
over the higher Sierra passes. Consequently, motorists should be
prepared for possible winter driving conditions in the mountains
this weekend. Good instability and shear this afternoon behind the
cold front will bring a threat of thunderstorms and possibly weak
tornadoes, especially within the northern and central Sacramento
Valley. Precipitation will taper off on Sunday with showers mainly
lingering over the Shasta County and down the Sierra. High
temperatures this weekend will be in the mid 60s to low 70s in the
Valley and mid 30s to low 50s in the mountains. Monday and Tuesday
will be drier and warmer with ridging dominating, expect for a
slight chance of rain over western Shasta county by Tuesday
afternoon.  JClapp


.Extended Discussion (Wednesday through Saturday)
Amplifying ridge forecast over the western US during the middle
of next week as another trough deepens over the eastern Pacific.
This will likely keep all but the far northern portion of the
forecast area precipitation-free into Thursday. Forecast
confidence decreases later in the week as significant differences
develop between the models in the handling of the trough as it
moves onto the west coast Halloween and next weekend. Though, it
appears much of the region will see a chance of precipitation
sometime next Friday or Saturday.

&&

.Aviation...
Pacific cold front moves across the area today bringing rain and
increasing winds along with areas of MVFR conditions to the valley
and widespread IFR conditions to the mountains. Wind gusts to 45
mph will be developing after 12Z, especially over the northern
Sacramento Valley and gusts over 50 mph will be likely over the
northern Sierra Nevada. Scattered showers along with isolated to
scattered thunderstorms will be likely behind the front this
afternoon into this evening.

&&

.STO Watches/Warnings/Advisories...
High Wind Warning until 11 pm PDT this evening Burney Basin /
eastern Shasta county...west slope Northern Sierra Nevada...
western Plumas county/Lassen Park.

Wind Advisory until 11 pm PDT this evening Clear Lake/southern
Lake county...mountains southwestern Shasta county to northern
Lake county...northeast foothills/Sacramento Valley...Shasta
Lake area / northern Shasta county.

Wind Advisory until 8 pm PDT this evening Carquinez Strait and
Delta...Sacramento Valley.

&&

$$

JClapp





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