Mostly Sunny with a high near 74°F[23°C]. East wind to around 2 mph[4 kph], with wind gusts to near 13,"windGustMPS":6 mph[22 kph]. The dewpoint will be near 50°F[12°C] with a humidity of 85% and a barometric pressure around 29.82 in[1010 mb]. The UVI forecast is 5. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Tonight
Clear with a low around 53°F[12°C]. West wind to around 6 mph[9 kph], with wind gusts to near 11,"windGustMPS":5 mph[18 kph]. The dewpoint will be near 41°F[7°C] with a humidity of 37% and a barometric pressure around 29.91 in[1013 mb]. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Friday
Sunny with a high near 76°F[25°C]. East southeast wind to around 3 mph[6 kph], with wind gusts to near 12,"windGustMPS":6 mph[20 kph]. The dewpoint will be near 42°F[7°C] with a humidity of 65% and a barometric pressure around 29.93 in[1014 mb]. The UVI forecast is 6. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Friday Night
Clear with a low around 55°F[13°C]. West wind to around 4 mph[6 kph], with wind gusts to near 14,"windGustMPS":6 mph[22 kph]. The dewpoint will be near 46°F[8°C] with a humidity of 42% and a barometric pressure around 29.97 in[1015 mb]. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Saturday
Sunny with a high near 77°F[25°C]. East wind to around 5 mph[9 kph], with wind gusts to near 14,"windGustMPS":6 mph[22 kph]. The dewpoint will be near 42°F[7°C] with a humidity of 60% and a barometric pressure around 29.97 in[1015 mb]. The UVI forecast is 5. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Saturday Night
Mostly Clear with a low around 55°F[13°C]. West southwest wind to around 7 mph[12 kph], with wind gusts to near 10,"windGustMPS":5 mph[17 kph]. The dewpoint will be near 44°F[7°C] with a humidity of 41% and a barometric pressure around 29.98 in[1015 mb]. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Sunday
Partly Cloudy with a high near 75°F[24°C]. East wind to around 6 mph[10 kph], with wind gusts to near 15,"windGustMPS":7 mph[24 kph]. The dewpoint will be near 43°F[7°C] with a humidity of 54% and a barometric pressure around 29.97 in[1015 mb]. The UVI forecast is 5. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Sunday Night
Partly Cloudy with a low around 56°F[13°C]. Southwest wind to around 8 mph[13 kph], with wind gusts to near 12,"windGustMPS":5 mph[19 kph]. The dewpoint will be near 45°F[8°C] with a humidity of 44% and a barometric pressure around 30.01 in[1016 mb]. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Monday
Partly Cloudy with a high near 73°F[23°C]. East wind to around 6 mph[9 kph], with wind gusts to near 16,"windGustMPS":7 mph[25 kph]. The dewpoint will be near 45°F[10°C] with a humidity of 57% and a barometric pressure around 30.00 in[1016 mb]. The UVI forecast is null. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Monday Night
Partly Cloudy with Isolated Showers with a low around 57°F[14°C]. West southwest wind to around 8 mph[13 kph], with wind gusts to near 13,"windGustMPS":6 mph[20 kph]. The dewpoint will be near 51°F[12°C] with a humidity of 57% and a barometric pressure around 30.04 in[1017 mb]. Chance of precipitation is 23% with a qpf of 0.01 in[0.3 mm].
Tuesday
Partly Cloudy with Light Rain Showers with a high near 71°F[22°C]. East wind to around 6 mph[9 kph], with wind gusts to near 15,"windGustMPS":7 mph[23 kph]. The dewpoint will be near 51°F[12°C] with a humidity of 74% and a barometric pressure around 30.05 in[1017 mb]. The UVI forecast is null. Chance of precipitation is 23% with a qpf of 0.03 in[0.7 mm].
Tuesday Night
Mostly Clear with a low around 54°F[12°C]. West wind to around 8 mph[13 kph], with wind gusts to near 12,"windGustMPS":5 mph[19 kph]. The dewpoint will be near 54°F[12°C] with a humidity of 66% and a barometric pressure around 30.06 in[1018 mb]. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Wednesday
Mostly Sunny with a high near 73°F[23°C]. East wind to around 6 mph[10 kph], with wind gusts to near 15,"windGustMPS":7 mph[23 kph]. The dewpoint will be near 48°F[10°C] with a humidity of 70% and a barometric pressure around 29.97 in[1015 mb]. The UVI forecast is null. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Wednesday Night
Mostly Clear with a low around 58°F[14°C]. West northwest wind to around 4 mph[7 kph], with wind gusts to near 10,"windGustMPS":5 mph[17 kph]. The dewpoint will be near 45°F[7°C] with a humidity of 44% and a barometric pressure around 29.94 in[1014 mb]. Chance of precipitation is 0% with a qpf of 0.00 in[0.00 mm].
Forecasts for: QPF - Max Wind Speed - Max Humidity - Snowfall - Ice Accumulation
000
FXUS66 KSTO 201954
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
1254 PM PDT Wed Sep 20 2023
.SYNOPSIS...
A chance of showers and thunderstorms over the Sierra tonight and
Thursday, otherwise cool and dry weather continues into the
weekend. Gusty northerly winds with low humidity will lead to
critical fire weather conditions tonight through Thursday
afternoon. Pattern change will bring rain chances early next week.
.Discussion...
The upper low off the coast of south Central
California will be moving eastward later today, continuing a
pattern of onshore flow and lower than normal temperatures, along
with a chance for isolated showers and thunderstorms in the Sierra
tonight into Thursday. Thursday, the upper low currently over
Canada will drop southwestward over Northern California, bringing
northerly winds to the northern Sacramento Valley, with sustained
speeds between 15-25 mph, and a 60-90% chance of gusts exceeding
30 mph. Winds are expected to be strongest overnight on Wednesday,
though breezy and even gusty conditions may continue into
Thursday afternoon. In addition to gusty winds, poor overnight
humidity recovery means that parts of the northern Sacramento
Valley and areas along the Coastal Range will see critical fire
weather conditions. The smoke currently causing haze and impacting
air quality in the Sacramento Valley will also likely continue to
influence the area through at least Thursday, thanks to the
northerly winds brought on by the low.
The upper low will then quickly move eastward on Friday and over the
weekend, leaving Northern California caught between a weak ridge to
the east and another upper low to the west over the Pacific. This
will cause onshore flow with locally breezy conditions, especially
in the Delta region. Temperatures are expected to remain below
normal with highs in the upper 70s to low 80s in the Valley. //SP
.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)...
The center of the upper level low that will be off the coast of
the Pacific Northwest on Saturday will primarily remain in place
into next week, though its intensity will fluctuate some. However,
as the system weakens early in the week, the axis of the trough
will shift slightly eastward to cover Northern California.
Ensembles are indicating this will result in onshore, breezy
conditions and widespread showers, primarily in the northern and
central Sacramento Valley, as well as in the surrounding
foothills. The NBM is currently showing a 20-60% chance of the
aforementioned area receiving at least 0.5" of rainfall over a 48
hour period from Monday to Tuesday, with a 10-15% chance further
south, through Sacramento. Conditions will begin to dry out on
Wednesday morning, though temperatures will remain below normal,
with highs in the upper 70s to mid 80s in the Valley. //SP
&&
.AVIATION...
General VFR conditions over interior NorCal next 24 hrs with
local MVFR visibilities in HZ due to wildfire smoke at times.
Isolated SHRA/TSRA possible (10-20% probability), mainly over the
Sierra Nevada 00Z Thursday-02Z Friday. Surface winds mainly below
12 kts except northerly winds 10-20 kts with gusts 20-30 kts in
the northern/central Sacramento Valley and surrounding terrain
after 03Z Thursday (primarily impacting KRDD and KRBL).
Southwesterly wind gusts 20-25 kts vicinity Delta through 12Z
Thursday. //KH
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 PM this evening to 5 PM PDT Thursday
for Central Sacramento Valley in Glenn, Colusa, Yuba, Northern
Sutter, and Butte County Below 1000 Ft-Eastern Mendocino NF-
Eastern Portion of Shasta/Trinity NF-Northern Sacramento Valley
to Southern Tehama County Line Below 1000 Ft-Northern Sierra
Foothills from 1000 to 3000 Ft. Includes portions of Shasta-
Trinity and Butte Units-Southeast Edge Shasta-Trinity NF and
Western Portions of Tehama-Glenn Unit-Southern Sacramento Valley
in Yolo-Sacramento Far Western Placer, southern Sutter and
Solano County Below 1000 Ft.
&&
$$