NWS Area Weather Forecast Discussion
County Warning Area [CWA]: STO Regional NWS Weather Office: Sacramento, CA
FXUS66 KSTO 291136
Area Forecast Discussion
National Weather Service Sacramento CA
336 AM PST Sun Nov 29 2020
Dry conditions with mild afternoons and cool nights are forecast
through the week. Breezy north to east winds are expected around
Upper level ridging continues over the region with light winds
and clear skies overnight. A fairly strong inversion is setting up
with warmer temperatures in the foothill thermal belts. For
example, Blue Canyon (5300 feet) at 3 am was 48 degrees. Below
the inversion in the Valley, winds are calm and there were some
frosty temperatures, such as Fairfield at 30 degrees, Modesto 31.
Expect areas of light frost by daybreak.
Temperatures today will be similar to on Saturday, with mild
Valley highs in the mid to upper 60s.
A weak system will pass through the region on Monday but will have
few effects other than bringing us some high clouds ahead of the
front and maybe some cumulus clouds over the northern mountains.
Dry conditions continue across the forecast area with
precipitation now expected to stay north of Shasta County.
Behind the front Monday night into Tuesday north to northeast
flow will set up. Winds should stay up enough over the north and
westside of the valley to help warm the overnight lows.
Temperatures will remain warmer than normal during the day with
the north and some spots on the westside of the valley noticeably
warmer than the rest of the valley. The strongest northerly winds
will be over the north and westside of the Valley and through
favored passes and northeast to southwest oriented canyons and
ridges for the mountains and foothills. Valley gusts up to 20-25
mph possible. Canyon winds could locally reach 40-50 mph in
places like Jarbo Gap early Wednesday. Lighter northerly winds are
forecast for Thursday. EK
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)...
Cluster analysis is in very good agreement we are likely to have
an amplified ridge over the West Coast throughout the extended
forecast period. This will mean dry and quiet weather for Northern
California. Forecast high temperatures are expected to be
anywhere from 5 to 15 degrees above average for this time of year.
It should be noted however, this high pressure pattern will also
yield cool, slightly below average lows for the Valley with
widespread 30s expected each morning. Locations along the thermal
belts will stay a bit warmer due with inversion in place. Low
temperatures for those areas will be closer to climatological
averages. Some of these foothill locations will actually see lows
5 to 10 degrees above average for this time of year.
VFR conditions expected with generally light winds under 10 kts.