Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 17, NWS Sacramento, CA

September 12, 2017Nevada County, Sierra County, California

NWS Sacramento, CA issued this severe thunderstorm warning at Sep 12, 2017, 2:57 PM PDT for Nevada County, Sierra County, California. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 12, 2017, 2:57 PM PDT (21:57 UTC)
Expired
Sep 12, 2017, 3:45 PM PDT
In force
48 min
Issued by
NWS Sacramento, CA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Nevada County, CA, Sierra County, CA

The radar

The Beale AFB radar (KBBX), 85 km from the middle of the area, began a volume at 21:59 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.

The nearest sounding before it

Reno, NV (KREV), launched 12:00Z, 10.0 hours before the alert went out and 210 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 12:00Z on 2017-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 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 12:00Z on 2017-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1891 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 8:04 PM PDTSpecial Weather StatementSTOStanislaus41 min
Sep 12, 12:51 PM PDTSpecial Weather StatementSTONevada24 min
Sep 12, 1:19 PM PDTSpecial Weather StatementSTOSierra26 min
Sep 12, 1:40 PM PDTSpecial Weather StatementSTOPlacer35 min
Sep 12, 2:18 PM PDTSpecial Weather StatementSTONevada42 min
Sep 12, 2:20 PM PDTSpecial Weather StatementSTOSierra25 min
Sep 12, 2:22 PM PDTSpecial Weather StatementSTOEl Dorado53 min
Sep 12, 2:32 PM PDTSpecial Weather StatementSTONevada43 min
Sep 12, 2:57 PM PDTSpecial Weather StatementSTOLake48 min
Sep 12, 3:25 PM PDTSpecial Weather StatementSTOEl Dorado35 min
Sep 12, 4:18 PM PDTSpecial Weather StatementSTONevada42 min
Sep 12, 4:49 PM PDTSpecial Weather StatementSTOPlumas41 min

Nearby

Severe Thunderstorm Warnings in California, 2017Every severe thunderstorm warning in 2017

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.