680  
FXUS66 KSTO 112033  
AFDSTO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SACRAMENTO CA  
133 PM PDT MON AUG 11 2025  
   
DISCUSSION  
 
   
SYNOPSIS  
 
WIDESPREAD MODERATE HEATRISK AND LOCAL MAJOR HEATRISK TODAY WITH  
TRIPLE DIGIT HIGHS IN THE VALLEY. GRADUAL COOLING TREND BEGINS  
TUESDAY AND CONTINUES INTO THE WEEKEND. DRY WEATHER PREVAILS.  
 
   
KEY MESSAGES  
 
*TODAY:  
- HIGH CONFIDENCE IN WELL ABOVE NORMAL TEMPERATURES TODAY AS  
UPPER LEVEL RIDGING REMAINS OVER THE REGION WITH WIDESPREAD  
MODERATE HEATRISK AND LOCAL MAJOR HEATRISK ACROSS THE VALLEY  
AND FOOTHILLS AND INTO THE MOUNTAINS  
- PROBABILITY OF HIGH TEMPERATURES > 100F:  
-NORTHERN SACRAMENTO VALLEY: 80-100%  
-REMAINDER OF THE VALLEY: 35-75%  
 
*TUESDAY-WEDNESDAY:  
- THE EAST PACIFIC RIDGE AXIS ALOFT WEAKENS AS AN UPPER TROUGH  
FROM WESTERN CANADA DROPS DOWN BRINGING INCREASED ONSHORE FLOW,  
COOLER TEMPERATURES, AND HIGHER RELATIVE HUMIDITY  
- THE INCREASED DELTA BREEZE WILL GIVE NOTICEABLE RELIEF FOR THE  
DELTA AND SOUTHERN SACRAMENTO VALLEY, ESPECIALLY BY WEDNESDAY  
MORNING  
- SLIGHTLY COOLER BUT STILL HOT TEMPERATURES ARE FORECAST FOR  
TUESDAY, AND THEN CONTINUED COOLING WILL BRING TEMPERATURES  
CLOSER TO SEASONABLE NUMBERS BY WEDNESDAY  
 
*THURSDAY-WEEKEND:  
- NEAR TO BELOW AVERAGE TEMPERATURES THEN CONTINUE LATER THIS  
WEEK AND INTO THE WEEKEND WITH RISING RELATIVE HUMIDITY  
- PERIODICALLY BREEZY ONSHORE FLOW IS FORECAST AT TIMES,  
STRONGEST IN THE DELTA VICINITY AND OVER THE SIERRA CREST  
- LOW CONFIDENCE IN ISOLATED THUNDERSTORM POTENTIAL ALONG THE  
HIGHER ELEVATIONS IN THE MOUNTAINS THIS WEEKEND (UP TO 10-15%  
CHANCE), DRY WEATHER ELSEWHERE  
   
CHANGES FROM PREVIOUS FORECAST  
 
- MENTION OF LOW ISOLATED MOUNTAIN THUNDERSTORM POTENTIAL THIS  
WEEKEND  
 
 
   
AVIATION  
 
VFR CONDITIONS EXPECTED TO PREVAIL NEXT 24 HOURS ACROSS INTERIOR  
NORTHERN CALIFORNIA. SUSTAINED SURFACE WINDS GENERALLY 12 KTS OR  
LESS AT TAF SITES. WEST-SOUTHWEST WIND GUSTS 15-25 KTS THROUGH THE  
DELTA UNTIL 15Z TUESDAY. ADJACENT PARTS OF THE SOUTHERN  
SACRAMENTO VALLEY WILL SEE SIMILAR WINDS AT 15-20KTS FROM 22Z  
MONDAY TO 06Z TUESDAY.  
 
 
   
STO WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
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