Alert archive / California / Mesoscale Discussions in 2005

Mesoscale Discussion 193

February 21, 2005Los Angeles County, Orange County, Ventura County, California

The Storm Prediction Center issued this mesoscale discussion at Feb 21, 2005, 12:48 PM PST for Los Angeles County, Orange County, Ventura County, California. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Feb 21, 2005, 12:48 PM PST (20:48 UTC)
Expired: Feb 21, 2005, 2:15 PM PST
In force: 87 min
Issued by: the Storm Prediction Center

Counties Los Angeles County, CA, Orange County, CA, Ventura County, CA

The radar

The Santa Ana Mts radar (KSOX), 46 km from the middle of the area, began a volume at 20:48 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 27Feb 21, 3:30 PM PST

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 8.8 hours before the alert went out and 111 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 645 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 243 m²/s²
0-3 km storm-relative helicity: 275 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.

Issued	Product	Office	Counties	Lasted
Feb 21, 2:10 AM PST	Mesoscale Discussion	SPC	Orange	3 hr
Feb 21, 6:38 AM PST	Mesoscale Discussion	SPC	Los Angeles, Orange, San Diego, Ventura	2 hr
Feb 21, 7:40 AM PST	Severe Thunderstorm Watch	SPC	Los Angeles, Orange, San Diego, Ventura	7 hr
Feb 21, 1:53 PM PST	Mesoscale Discussion	SPC	Alameda, Amador, Calaveras, Contra Costa, Fresno, Kings and 18 more	2 hr
Feb 21, 3:30 PM PST	Severe Thunderstorm Watch	SPC	Amador, Calaveras, Fresno, Kern, Kings, Los Angeles and 11 more	7 hr

Nearby

Mesoscale Discussions in California, 2005 Every mesoscale discussion in 2005

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.