247
FXUS66 KSTO 142009
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
109 PM PDT Mon Jul 14 2025

For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.

.DISCUSSION...

.SYNOPSIS...
Hot weather continues today with Moderate to locally Major
HeatRisk. Increasing Delta breeze influence will bring minor
cooling and overnight relief tonight and through the week in the
Delta and adjacent Valley locations. Dry weather and periodically
breezy onshore winds are expected through Friday alongside
temperatures returning to near normal mid to late week.

&&

.KEY MESSAGES...

* Heat Advisory remains in effect through 11 PM tonight for the
  northern/central Sacramento Valley and surrounding foothills and
  mountain locations.

*  Today-Tuesday:

 - Widespread Moderate HeatRisk with areas of Major HeatRisk across
   interior NorCal.
 - Smoke will continue to impact areas in the vicinity of the
   Green Fire, though more southerly winds this evening and on
   Tuesday should keep most smoke out of the Valley during the day.
 - Locally breezy northerly flow in the northern/central
   Sacramento Valley and adjacent terrain, mainly in the overnight
   through morning timeframe.
 - Increasing onshore flow and Delta Breeze influence expected
   through the weekend, bringing minor cooling and overnight
   relief to the Delta and adjacent Valley.
- Breezy to gusty southerly winds expected Tuesday evening,
      especially in the vicinity of the Delta.
- Probability of gusts 30 mph or greater on Tuesday:
- 20 to 50% in the central and northern Sacramento Valley
- 60 to 95% in the Delta and vicinity
 - Low daytime relative humidity today with moderate to poor
   overnight recoveries over foothills and mountains. Humidities
   improve slightly throughout this week, especially closer to the
   Delta.
 - Low (5-10%) chance for isolated thunderstorms across the high
   terrain of Shasta County during the afternoon/evening today.

*  Wednesday-Sunday:

 - Upper level pattern remains largely persistent with broad
   troughing/northwesterly flow across interior NorCal. Some
   signals for ridging and increasing heights aloft into next
   weekend.
 - A slight cool down to more seasonable temperatures mid to late
   week, followed by a gradual warming trend by next weekend.
 - Periodically breezy onshore flow expected to persist in the
   afternoon and evening, shifting toward terrain driven
   influence during the overnight hours.
 - Persistent and periodic late day wind gusts 20 to 30 mph
   anticipated throughout the Delta and vicinity each day.

.Changes from previous forecast...
 - Minimal changes from the previous forecast.

&&

.AVIATION...
Wildfire smoke will result in MVFR, IFR, and LIFR conditions at
times in the northern Sacramento Valley, including KRDD. VFR
conditions expected elsewhere across interior Northern California
over the next 24 hours. West-southwest winds will be breezy
through the Delta with gusts 15 to 25 kts through 18Z Tuesday.
Elsewhere, sustained speeds generally at or below 12 knots over
the next 24 hours, with periodic gusts 15 to 20 kts in the Valley
between 22Z Monday and 06Z Tuesday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 11 PM PDT this evening for Burney Basin /
Eastern Shasta County-Central Sacramento Valley-Mountains
Southwestern Shasta County to Western Colusa County-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Shasta
Lake Area / Northern Shasta County-Western Plumas County/Lassen
Park.

&&

$$