284
FXUS66 KSTO 171909
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
1209 PM PDT Sun May 17 2026
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.KEY MESSAGES...
- A Red Flag Warning is currently in effect for the Valley and
Delta below 1000 feet, and continues until 8 PM Monday.
- Critical fire weather concerns for the Valley & Delta, with
gusty north winds and low humidity. Strongest winds through
tonight along and west of the I-5 corridor.
- Above-normal temperatures continue through the forecast period
with Minor to Moderate HeatRisk.
&&
.DISCUSSION...
...Today & Monday...
Highs are expected to be in the high 70s to low 80s across the
Valley, and in the 60s to mid 70s in the foothills. Gusty north to
east winds peak today in the Valley, with gusts up to 40 to 50
mph through the evening. Valley winds will gradually decrease
overnight before picking up slightly again on Monday; however,
wind speeds on Monday will generally be lower than today, up to 35
mph in the Valley through Monday evening. Delta wind speeds will
continue to gust up to 50 mph through Monday evening. A Wind
Advisory for portions of the Valley and Delta remains in place
until 8pm tonight. Additionally, with daytime humidities falling
into the single digits and teens throughout the Valley, and poor
overnight recoveries, a Red Flag Warning remains in place for
elevations below 1000 ft through 8pm Monday.
...Tuesday to Saturday...
A warming trend continues on Tuesday and through the late week,
with increasing areal coverage of Moderate HeatRisk in the Valley
and foothills. Thursday also sees 70 to 90% chance of triple digit
temperatures, primarily in the central and southern Sacramento
Valley east of I-5. Daytime relative humidities will also remain
in the single digit to teen range through at least the end of the
week. This means that even with light winds in the forecast for
the remainder of the week, some elevated fire weather risk will
remain. It therefore remains important to practice fire safety
this week! There is some indication that ridging will flatten out
and therefore that temperatures will cool slightly over the
weekend, but there is still some uncertainty in the forecast. Make
sure to stay up to date at weather.gov/sacramento.
&&
.AVIATION...
VFR conditions are expected over the next 24 hours. Northerly
winds 20-30 kts with gusts 30-40 kts for the Valley and Delta
through tonight. Then, northerly wind gusts up to 15-30 kts in the
Valley and Delta until 00z Tuesday. Northeast to east winds 20-35
kts with gusts up to 35-50 kts over the Sierra through tonight,
then gusts up to 20-35 kts through mid-day Monday.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 8 PM PDT Monday for Butte County Below
1000 ft-C. San Joaquin County including Stockton-C. Solano
County including Fairfield-C. Stanislaus County including
Modesto-C. Yolo/NE Solano including Woodland-Central Colusa
County Incl. I-5-Central Glenn Co & Interstate 5-Eastern Colusa
County-Eastern Glenn County-N. Sac Valley in Tehama County-NE
San Joaquin Valley Below 1000 ft-SW Solano County including
Vallejo-Sac Metro/W. El Dorado/Amador County-Sacramento County
Delta-San Joaquin County Delta-Shasta Metro-Sutter/Yuba counties
below 1000 ft-Tracy Triangle Below 1000 ft-W. Stanislaus County
Above 1000 ft & I-5-W. Yolo County including Capay/I-505.
Wind Advisory until 8 PM PDT this evening for Butte County Below
1000 ft-C. Solano County including Fairfield-C. Yolo/NE Solano
including Woodland-Central Colusa County Incl. I-5-Central Glenn
Co & Interstate 5-Eastern Colusa County-Eastern Glenn County-N.
Sac Valley in Tehama County-SW Solano County including Vallejo-
Sacramento County Delta-San Joaquin County Delta-Shasta Metro-
Sutter/Yuba counties below 1000 ft-W. Yolo County including
Capay/I-505.
&&
$$
