Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Sacramento California
330 am PST Fri Nov 24 2017
dry weather with mild temperatures today and Saturday. More
widespread rain spreads south Saturday night and Sunday followed
by a colder system early next week.
satellite imagery shows plenty of high clouds continuing to move
across interior norcal from the west and southwest as the upper
ridge reasserts itself. A few light showers linger near the Oregon
border. Still some patches of fog and stratus in the valleys
beneath the higher clouds with a few locations occasionally
reporting visibility below a mile. Current temperatures remain
rather mild ranging from the mid 30s and 40s in the mountain
valleys to the 50s and lower 60s in the Central Valley.
Dry weather returns to the forecast area today with the ridge
moving overhead. Temperatures will remain unseasonably mild, but
perhaps not quite as mild as Thanksgiving for many areas as the
subsidence inversion strengthens.
Most of the region will remain dry and mild on Saturday. The
inversion weakens as a weak weather system brushes the far north
and much of the area may see a little milder temperatures
compared to today. Precip chances will be limited to the far
northern portion of the state.
More widespread precip is expected Saturday night into Sunday,
with high snow levels. A colder system arrives Sunday night and
continues into Monday. This system has been trending wetter, with
accumulating snow looking more and more likely to impact travel
Sunday night into Monday. Snow levels are expected to drop below
the higher northern Sierra pass levels by Sunday evening, and
travelers should be prepared for winter driving conditions.
Extended discussion (tuesday through friday)
drier weather is expected across the region toward the middle of
next week as high pressure over the eastern Pacific builds into
California. A bit of north wind may occur during this timeframe,
but it remains to be seen whether this will inhibit valley fog
formation. Look for high temperatures to be within a few degrees
Both the GFS and European model (ecmwf) bring a closed upper low toward the coast
late next week. This may signal a change toward more active
weather, as both models bring a series of more potent systems
toward the region next weekend. Dang
patchy fog has begun to pop up across portions of the Central
Valley. Expect local IFR/LIFR conditions through late morning,
improving to VFR/MVFR for the afternoon. Light winds continue.