Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 201656

956 AM PDT Sun Apr 20 2014

Warm temperatures under high pressure ridge this afternoon. A
Pacific trough will approach the coast Monday bringing increasing
clouds and a chance of rain and higher elevation snow Monday
night and Tuesday. Another trough will bring unsettled conditions
Friday and Saturday.


Temperatures are running 5 to 10 degrees warmer versus 24 hours at
most valley locations. Have updated forecast to raise high temps
a few degrees to match better with short term guidance. This gives
high temperatures in the low to mid 80`s for valley areas.
Otherwise...dry conditions with generally light winds. A weak
delta breeze will develop through the delta...but not move farther
east than about Davis.

.Previous Discussion...
Weak high pressure building over the region today will produce
light northerly winds and warmer temperatures. Highs today will be
in the low to mid 80s in the central valley with 60s to lower 70s
for the mountains.

On Monday a stronger shortwave will approach the interior and may
be able to produce a few mountains showers for the afternoon over
the far northern sections ahead of the front. At this time the
system looks to start to move inland Monday night. Cooler air
filtering into the region will cool valley temperatures back into
the 70s.

The system will still be impacting the interior on Tuesday with
showers and isolated thunderstorms expected over most of the
interior. Snow levels will remain above pass level through Monday
but lower Monday night and Tuesday below major pass levels in the
Sierra Nevada. Not a lot of snow or precipitation is forecast at
this time but several inches of snow near pass levels look
possible. Temperatures will continue to cool on Tuesday which
looks like the coldest day this week. Highs will be in the 60s for
the central valley.

On Wednesday the system will have moved well to the northeast of
the area to keep most areas dry. Zonal flow into the far northern
part of the state may produce a few showers over the southern
Cascades otherwise expect dry and warmer conditions to prevail.

.Extended Discussion (Thursday through Sunday)

Mostly dry conditions on Thursday with above normal daytime highs.
Could see a few lingering showers over the northern mountains,
though. Valley highs in the mid to upper 70s with some isolated
spots reaching 80. By Friday, NorCal will transition back to a
cooler, wetter pattern as a cold front brings chances of
precipitation over much of the area by afternoon. Additional
storm waves will continue through the weekend, with continued wet periods
and below normal temperatures. However, models are out of synch
for the details over the weekend. The GFS & GEM show another wet
storm impacting NorCal on Saturday but the ECMWF shows less
precipitation for that system. Then on Sunday, the ECMWF shows a
wetter storm wave moving into NorCal while the GFS & GEM trend towards
a weak ridge over the region. Have generally kept a mention of
precipitation through the weekend until details become more clear.



VFR conditions will continue the next 24 hours across interior
Northern California. North to Northwest winds 5-15 kt for TAF
sites. Stronger winds will develop again in the delta region with
gusts up to 25 kt.


.STO Watches/Warnings/Advisories...

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