Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 111017

317 AM PDT Fri Apr 11 2014

A weak system will bring a slight chance of showers and
thunderstorms mainly over the mountains Friday and Saturday. High
pressure and well above normal temperatures dominate into early
next week, followed by a series of weak troughs that move through
northern California by the middle of next week.


.Short Term Discussion (Today through Monday)...
Satellite imagery shows a cutoff low is currently near 32N 130W
and slowly drifting eastward. High clouds associated with the
system have since moved over most of California. A dry slot will
likely spread into the southern half of California today.

Closer proximity of the cutoff low and the cloud cover will keep
temperatures today and Saturday at least several degrees cooler
than Thursday. Nevertheless, temperatures are still expected to be
around 10 degrees warmer than normal.

The aforementioned cutoff low will move toward Southern
California today, and inland tonight. While most of the dynamics
will remain to our south, weather models have consistently shown
that increasing moisture and instability may bring showers and
thunderstorms this afternoon/evening and potentially again
Saturday. These showers should be isolated in nature and
generally confined to the higher elevations of the Sierra and
Shasta-Trinity/Mendocino mountains.

The upstream ridge builds over the the West Coast Sunday/Monday,
with a return of drier, more stable air and rising temperatures.


.Extended Discussion (Tuesday through Friday)
Tuesday/Wednesday...the GFS tracks a low through northern
California which would continue a shower threat and also notably
reduce temperatures and snow levels. Euro keeps flat ridge over
the area with main moisture/energy tracking north of the region.
Have used a blend of solutions given uncertainty which will keep
low shower chances in place.

An unsettled west-northwest flow pattern remains over far
northern California through the rest of the extended period,
though model discrepancies keep the strength and timing fairly
uncertain. Have continued shower chances mainly for the mountains
Thursday and Friday.


High pressure dominates with VFR conditions the next 24 hours.
Local southwesterly gusts to 25 kts possible through the delta
during the late afternoon.


.STO Watches/Warnings/Advisories...

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