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Area forecast discussion 
National Weather Service Sacramento California
256 am PDT Sat Apr 25 2015

Synopsis...
a fast moving wet system pushes out of the area today with
scattered showers continuing across the mountains through this evening.
High pressure brings dry conditions Sunday through mid week next
week. Warmest temperatures Monday with slight cooling trend
through the end of the week.

&&

Discussion...
system currently moving across the area, with precipitation shield mainly
south of Redding and Red Bluff areas. Precipitation overnight has
been fairly steady and wetting in these areas with totals so far
ranging for a few hundredths in far northern and southern portions
of the valley and upwards of a half to three quarters of an inch
across central portions. Snowfall rates picked up after midnight
with moderate to at times heavy snowfall across the Sierra. Snow
levels generally in the 5000-6000 ft range. Chain controls in
place across I-80 and Highway 50 with slow-going and hazardous
travel likely continuing into at least the morning hours.
Travelers should continue to monitor caltrans Road conditions
before hitting the Road this morning. Latest hi-res guidance (like
hrrr, WRF, nam) has good handle on current situation and leaned
heavily on it for today's forecast. These solutions move precip
east out of the valley around daybreak this morning with dry
weather for the rest of the day. Have sped up timing of pops
accordingly in this area. Showers should linger in the mountains
through much of the day, but heaviest of precip will be tapering
off during the morning hours. Additional accumulations should be
light. Will continue winter wx advisory as is and let day shift
monitor trends and evaluate. Temperatures today should top out a
few degrees below normal with upper 60s to low 70s in the valley
and upper 30s to 50s in the foothills and mountains.

Ridging will build back in behind the departing system for Sunday
into mid-week. Dry weather will rule with mostly clear skies. This
will also kick off a warming trend with temperatures returning to
much above normal by Monday and Tuesday. A few locations in the
northern valley may once again see highs in the 90s on Monday.

Ceo

Extended discussion (wednesday through saturday)

High amplitude ridge forecast to break down and shift east
Wednesday as upstream trough digs southeastward from the Gulf of
Alaska. Result will be increasing onshore flow with minor synoptic
cooling trend. Trough is progged to move across norcal Thursday
with the GFS/Gem digging it further south than the ec. Continue to
lean forecast toward the deeper solutions and will continue to
mention a threat of showers and thunderstorms over the northern
mountains Thursday afternoon into evening. Greater cooling
expected Thursday. Models differ from broad troughing aloft to
weak upper ridging Friday into Saturday, but all suggest drier
weather with a slight increase in Max temps.

&&

Aviation...

Widespread MVFR with local IFR conditions in the Central Valley
through about 16z as the large area of rain shifts southeast, then
mainly VFR conditions and lighter winds expected with only local
MVFR conditions near remaining showers. Over northern Sierra,
widespread IFR conditions in rain and snow expected through about
18z with southwesterly winds 30-40 kts across the higher
elevations, then areas of MVFR conditions expected into this
evening with lingering showers and decreasing wind. Snow levels
050-055.

&&

Sto watches/warnings/advisories...
Winter Weather Advisory until 5 PM PDT this afternoon above 5000
feet in the West Slope northern Sierra Nevada...western Plumas
County/Lassen park.

&&

$$

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