Alert archive / California / Mesoscale Discussions in 2011

Mesoscale Discussion 230

March 18, 20117 counties in California

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2011, 9:26 AM PDT for 7 counties in California. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2011, 9:26 AM PDT (16:26 UTC)
Expired
Mar 18, 2011, 1:30 PM PDT
In force
4 hr
Issued by
the Storm Prediction Center

Counties Alpine County, CA, El Dorado County, CA, Nevada County, CA, Placer County, CA, Plumas County, CA, Sierra County, CA, Tuolumne County, CA

The radar

The Beale AFB radar (KBBX), 86 km from the middle of the area, began a volume at 16:30 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

Oakland, CA (KOAK), launched 12:00Z, 4.4 hours before the alert went out and 221 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, Oakland, CA at 12:00Z on 2011-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 21 joules per kilogram.LCLLFCEL10008507005003002001001 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, Oakland, CA at 12:00Z on 2011-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 203 square meters per square second.1939587897117Sfc1 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
21 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
757 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
203 m²/s²
0-3 km storm-relative helicity
285 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 11:37 AM PDTMesoscale DiscussionSPCSan Mateo, Santa Cruz53 min

Nearby

Mesoscale Discussions in California, 2011Every mesoscale discussion in 2011

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.