FXUS66 KSTO 042039

AFDSTO



Area Forecast Discussion

National Weather Service Sacramento CA

139 PM PDT Tue Aug 4 2026



For additional details on weather and expected impacts over the

next 7 days, please visit weather.gov/sto/briefing.







.KEY MESSAGES... 



 - Hot and dry conditions continue this week, with widespread

   Moderate HeatRisk.



 - Elevated Fire Weather Conditions in the northern Sacramento

   Valley and surrounding terrain, Burney Basin, and Sierra

   Foothills through Saturday due to hot temperatures and low 

   humidities.



 &&





.DISCUSSION...



Today-Saturday...

Upper level ridging begins to flatten out today, allowing for

marginally cooler daytime highs compared to yesterday (but only 

by a few degrees) and increased onshore flow through the Delta. 

Widespread Moderate HeatRisk continues today and through the 

remainder of the week. The aforementioned increase in onshore 

flow will continue through midweek as the ridge continues to 

weaken slightly. This will provide minor relief from the heat 

especially during the overnight period. Overnight low temperatures

and maximum relative humidities will remain elevated in the 

foothills throughout this period, with only the Delta and Valley 

receiving marginal benefits from this increased onshore influence.

Outside of the Greater Sacramento Area and Delta, daytime RHs in 

the Valley will remain in the upper single digits to mid teens 

through Saturday. Additionally smoke from the Gann Wildfire 

located in Calaveras County will continue affecting surrounding 

communities with west winds pushing near surface smoke into the 

foothills and southwesterly transport winds advecting lofted smoke

northward.



This "cooling" trend is expected to be short-lived, as the EC 

ensemble guidance shows the upper ridge amplifying once again 

over Northern California Friday into the weekend, resulting in 

another period of hot and dry conditions similar to those earlier

this week. Areas of Major HeatRisk are already creeping into the 

foothills on Saturday, and this area of coverage may increase as 

we approach the weekend. 



As a result of these continued hot and dry conditions, fire 

weather conditions will remain elevated through Saturday across 

the northern Sacramento Valley and surrounding terrain, the Sierra

foothills, and Burney Basin. 







Sunday into early next week...

Ensembles show the upper ridge beginning to break down on Sunday

allowing for temperature to cool off slightly as offshore

troughing develops to the northwest. This offshore troughing is

forecast to deepen early next week, potentially knocking some 

Valley locations finally out of the triple digits.







&&





.AVIATION...



VFR conditions are expected to prevail over the next 24 hours. 

Winds generally remain 12 kts or less at TAF sites. West to 

southwest gusts up to 25 kts in the Delta from 00Z through 18Z 

Wednesday. 



&&



.STO WATCHES/WARNINGS/ADVISORIES...

None.

&&



$$