Alert archive / California / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 13, NWS Sacramento, CA

April 9, 2026San Joaquin County, Stanislaus County, California

NWS Sacramento, CA issued this severe thunderstorm warning at Apr 9, 2026, 7:14 PM PDT for San Joaquin County, Stanislaus County, California. It was in force for 31 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 9, 2026, 7:14 PM PDT (02:14 UTC)
Expired
Apr 9, 2026, 7:45 PM PDT
In force
31 min
Issued by
NWS Sacramento, CA
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties San Joaquin County, CA, Stanislaus County, CA

The radar

The San Francisco radar (KMUX), 87 km from the middle of the area, began a volume at 02:16 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Reno, NV (KREV), launched 00:00Z, 2.2 hours before the alert went out and 333 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Reno, NV at 00:00Z on 2026-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 29 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Reno, NV at 00:00Z on 2026-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
29 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
2279 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
140 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

529 
WUUS56 KSTO 100214
SVRSTO
CAC077-099-100245-
/O.NEW.KSTO.SV.W.0013.260410T0214Z-260410T0245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sacramento CA
714 PM PDT Thu Apr 9 2026

The National Weather Service in Sacramento has issued a

* Severe Thunderstorm Warning for...
  East central San Joaquin County in central California...
  Central Stanislaus County in central California...

* Until 745 PM PDT.

* At 714 PM PDT, a severe thunderstorm was located near Riverdale
  Park, or 8 miles west of Ceres, moving north at 15 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* Locations impacted include...
  Modesto, Ceres, Manteca, Riverbank, Patterson, Ripon, West Modesto,
  Riverdale Park, Shackelford, Salida, Empire, Westley, Bret Harte,
  Bystrom, Grayson, Del Rio, and Keyes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3745 12103 3751 12123 3780 12119 3768 12084
TIME...MOT...LOC 0214Z 201DEG 13KT 3756 12110 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

NR
2 follow-up statements
860 
WWUS56 KSTO 100225
SVSSTO

Severe Weather Statement
National Weather Service Sacramento CA
725 PM PDT Thu Apr 9 2026

CAC077-099-100245-
/O.CON.KSTO.SV.W.0013.000000T0000Z-260410T0245Z/
San Joaquin CA-Stanislaus CA-
725 PM PDT Thu Apr 9 2026

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM PDT
FOR EAST CENTRAL SAN JOAQUIN AND CENTRAL STANISLAUS COUNTIES...

At 724 PM PDT, a severe thunderstorm was located over Riverdale Park,
or near Ceres, moving north at 15 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
Modesto, Ceres, Manteca, Riverbank, Patterson, Ripon, West Modesto,
Riverdale Park, Shackelford, Salida, Empire, Westley, Bret Harte,
Bystrom, Grayson, and Del Rio.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3748 12101 3753 12123 3780 12119 3768 12084
TIME...MOT...LOC 0224Z 201DEG 13KT 3760 12108 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

NR
169 
WWUS56 KSTO 100242
SVSSTO

Severe Weather Statement
National Weather Service Sacramento CA
742 PM PDT Thu Apr 9 2026

CAC077-099-100250-
/O.EXP.KSTO.SV.W.0013.000000T0000Z-260410T0245Z/
San Joaquin CA-Stanislaus CA-
742 PM PDT Thu Apr 9 2026

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL SAN JOAQUIN AND
CENTRAL STANISLAUS COUNTIES WILL EXPIRE AT 745 PM PDT...

The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire. A new Severe 
Thunderstorm Warning remains in effect for portions of Stanislaus 
and San Joaquin Counties until 815 PM PDT.

LAT...LON 3748 12101 3753 12123 3780 12119 3768 12084
TIME...MOT...LOC 0240Z 201DEG 13KT 3765 12106 

$$

NR

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Apr 9, 1:08 PM PDT, 6 hours 6 minutes earlier. Its key messages:

  • Cooler temperatures and active weather today through the weekend with rain, strong to severe thunderstorms, gusty winds, and significant mountain snow
  • Winter Storm Warning in effect for the Sierra and Southern Cascades Friday evening through Sunday evening
Area forecast discussion, Apr 9, 1:08 PM PDT, 6 hours 6 minutes before
Area Forecast Discussion
National Weather Service Sacramento CA
108 PM PDT Thu Apr 9 2026

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

.KEY MESSAGES...

 - Cooler temperatures and active weather today through the
   weekend with rain, strong to severe thunderstorms, gusty winds,
   and significant mountain snow

 - Winter Storm Warning in effect for the Sierra and Southern
   Cascades Friday evening through Sunday evening

&&

.DISCUSSION...

...Today through the Weekend...
Current radar and satellite imagery show showers and thunderstorms
starting to develop across far northern California, including the
higher terrain of the Coast Range, Shasta County and southern
Cascades. A pattern change is bringing cooler and wetter weather
to the region today through the weekend. Temperatures are
currently trending approximately 5 to 8 degrees cooler than this
time yesterday. Forecast highs will be in the 50s to 60s in the
mountains and 60s to around 80 in the Valley and foothills today,
continuing to cool with highs in the 30s to 60s by the weekend.

Scattered showers and thunderstorms will impact the area through
the weekend as well. Latest forecast precipitation amounts have
trended slightly higher than the previous forecast. Slick roads
and minor travel delays can be expected from rain. The latest
probability of thunder from the National Blend of Models indicated
a 45-65% chance for today and Friday for thunderstorms across
basically our entire forecast area. High resolution guidance
depicts sufficient CAPE and shear values that could lead to severe
hail (1.00+ inch), and also weak tornadoes or funnel clouds.
These impacts will be in addition to the threat for brief heavy
rain, gusty winds and lightning. Thunderstorm chances will also
linger into Saturday and Sunday. When thunder roars, go indoors!

The snow forecast has also trended slightly higher since the
previous forecast. The Winter Storm Watch has been upgraded to a
Winter Storm Warning from Friday evening through Sunday evening
for elevations above 4500 feet. Snow levels will initially be at
pass level or above on Friday, and will lower below the passes
over the weekend. Heaviest snow rates and lowest snow levels are
expected to be from Saturday afternoon through Sunday where major
impacts to mountain travel are anticipated. Mountain travel is
discouraged this weekend while the Warning is in effect. Gusty
southerly winds are also forecast, with the strongest on Saturday.
The north/central Sacramento Valley, northeast foothills and
Sierra Crest will see the strongest winds. We will continue to
montior the trends in the forecast to see if a product will be
needed for the winds.

...Early Next Week...
There may be some lingering showers mainly in the mountains on
Monday. Otherwise drier and warmer weather is projected to return
early to mid next week. Forecast highs will generally be in the
60s to 70s in the Valley and foothills.

&&

.AVIATION...
Primarily VFR conditions over the next 24 hours, except within
thunderstorms through 09z Friday, and again between 18z Friday and
09z Saturday, which will bring potential for brief MVFR/IFR
conditions in any heavy rainfall. Surface winds generally at or
below 12 kt in the Valley through 12z Saturday, before southerly
wind speeds begin to increase across interior NorCal and continue
through late Saturday; gusts up to 35-45 mph in the Valley and up
to 50 mph in the mountains at times. Gusty and erratic winds will
occur near any thunderstorms as well.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 5 PM Friday to 11 PM PDT Sunday for
West Slope Northern Sierra Nevada-Western Plumas County/Lassen
Park.

&&

The office that day

Everything else NWS Sacramento, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 9, 5:01 PM PDTSevere Thunderstorm WarningSTOShasta, Tehama29 min
Apr 9, 5:22 PM PDTSevere Thunderstorm WarningSTOShasta38 min
Apr 9, 6:52 PM PDTSevere Thunderstorm WarningSTOSan Joaquin, Stanislaus38 min
Apr 9, 7:39 PM PDTSevere Thunderstorm WarningSTOSan Joaquin, Stanislaus36 min
Apr 10, 7:50 AM PDTSevere Thunderstorm WarningSTOButte, Nevada, Plumas, Sierra, Yuba40 min
Apr 10, 1:55 PM PDTSevere Thunderstorm WarningSTOSan Joaquin, Stanislaus35 min
Apr 10, 2:13 PM PDTSevere Thunderstorm WarningSTOStanislaus15 min
Apr 10, 2:21 PM PDTTornado WarningSTOSan Joaquin, Stanislaus24 min
Apr 10, 2:38 PM PDTSevere Thunderstorm WarningSTOStanislaus26 min
Apr 10, 2:40 PM PDTSevere Thunderstorm WarningSTOCalaveras, San Joaquin, Stanislaus35 min
Apr 10, 3:00 PM PDTSevere Thunderstorm WarningSTOSacramento, San Joaquin, Solano, Yolo30 min
Apr 10, 4:08 PM PDTSevere Thunderstorm WarningSTOCalaveras, Tuolumne25 min

Nearby

Severe Thunderstorm Warnings in California, 2026Every severe thunderstorm warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.