California, 2025Heat in California, August 3, 2025
August 3, 2025 · NWS STO · 1 event in 1 county or zone
A 15 month old child was left in a hot car which resulted in a fatality. Temperatures were in the low 80s to near 90 around Grass Valley with nearby max temperatures at a CWOP observation (K9JM Grass Valley) reporting at 89 degrees on Saturday and 86 degrees on Sunday.
- Deaths
- 1
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
A 15 month old child was left in a hot car which resulted in a fatality. Temperatures were in the low 80s to near 90 around Grass Valley with nearby max temperatures at a CWOP observation (K9JM Grass Valley) reporting at 89 degrees on Saturday and 86 degrees on Sunday.
What forecasters said that day
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before the first event at Aug 3, 12:37 PM PST, 3 hours 23 minutes earlier. Its key messages:
- * Today:
- Thunderstorm chances around 5-15% over the Shasta County mountains this afternoon/evening.
- Main threats include lightning, brief heavy rain, gusty winds, small hail, and possible fire starts. Short term models show convection initiating around 3 PM until 7 PM. Trends indicate storms remaining north of Shasta County, but an isolated shower or thunderstorms is still possible in our area.
- Elevated fire weather conditions are expected in the mountains due to the lightning and gusty outflow wind threat and any strikes outside the main precipitation cores will pose the threat for fire starts.
- Increased westerly flow through gaps and canyons in the Coastal Range for only a few hours this afternoon with gusts 20-30 mph.
- Breezy onshore flow expected during the afternoons and evenings.
- Probability of south to west wind gusts across the Delta and adjacent Valley > 30 mph: 60-90%
- Afternoon highs in the 90s throughout the Valley. * Monday-Thursday:
Area forecast discussion, Aug 3, 12:37 PM PST, 3 hours 23 minutes before
Area Forecast Discussion
National Weather Service Sacramento CA
137 PM PDT Sun Aug 3 2025
.DISCUSSION...
.SYNOPSIS...
Chances for afternoon and evening thunderstorms continue today
over the Shasta County mountains. Near to slightly below normal
temperatures are expected early this week with breezy winds. A
warming and drying trend is then anticipated from mid week onward
with areas of Moderate HeatRisk returning by late next week.
&&
.KEY MESSAGES...
* Today:
- Thunderstorm chances around 5-15% over the Shasta County
mountains this afternoon/evening.
- Main threats include lightning, brief heavy rain, gusty winds,
small hail, and possible fire starts. Short term models show
convection initiating around 3 PM until 7 PM. Trends indicate
storms remaining north of Shasta County, but an isolated shower
or thunderstorms is still possible in our area.
- Elevated fire weather conditions are expected in the mountains
due to the lightning and gusty outflow wind threat and any
strikes outside the main precipitation cores will pose the
threat for fire starts.
- Increased westerly flow through gaps and canyons in the Coastal
Range for only a few hours this afternoon with gusts 20-30 mph.
- Breezy onshore flow expected during the afternoons and
evenings.
- Probability of south to west wind gusts across the Delta and
adjacent Valley > 30 mph: 60-90%
- Afternoon highs in the 90s throughout the Valley.
* Monday-Thursday:
- Temperatures cool down slightly on Monday as a quick moving
system exists the region.
- Gradual warming and drying trend expected mid to late week as
Desert Southwest ridging amplifies.
- Periodically breezy onshore flow looks to continue as split
flow aloft persists over interior NorCal.
- High temperatures trend slightly above normal by the end of the
week, with 90s to lower triple digits through the Valley,
Delta, and foothills resulting in areas of Moderate HeatRisk.
.Changes from previous forecast...
- Increased westerly winds over the Coastal Range and Sierra
this afternoon and early evening, 40-60% chance of gusts > 30
mph.
&&
.AVIATION...
Generally VFR conditions expected to prevail next 24 hours across
interior NorCal. MVFR/IFR possible due to a slight (5-10%) chance
for isolated mountain showers/thunderstorms across Shasta County
mountains today until around 03Z Monday. Increased breezy onshore
surface winds up to 12 kts expected through Valley and Delta with
gusts 15 to 20 kts in the Valley until 08Z Monday and up to 25 kts
in the Delta and vicinity area through 18Z Monday. Westerly winds
over the Coastal Range and Sierra are expected to gust up to 25
kts until around 10Z Monday.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
Heat, Motherlode/Camptonville to Groveland
- When
- August 3, 4:00 PM PST to 9:00 PM PST
- Where
- Motherlode/Camptonville to Groveland forecast zone
- Deaths
- 1 direct, 0 indirect
- Reported by
- Law Enforcement
The Nevada County Sheriff's Office reported that first responders were called to Ragan Way in the Alta Sierra area south of Grass Valley on Sunday evening over reports of a child left in a hot car. A Nevada County Consolidated Fire crew started life-saving measures on the 15-month-old child, but the sheriff's office says the toddler died from being left in the hot car. Temperatures were in the low 80s to near 90 around Grass Valley with nearby max temperatures at a CWOP observation (K9JM Grass Valley) reporting at 89 degrees on Saturday and 86 degrees on Sunday.
- Heat
- Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
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NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1285157.