Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 572

April 20, 201213 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2012, 1:30 PM CDT for 13 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 20, 2012, 1:30 PM CDT (18:30 UTC)
Expired
Apr 20, 2012, 3:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Brooks County, TX, Cameron County, TX, Duval County, TX, Hidalgo County, TX, Jim Hogg County, TX, Jim Wells County, TX, Kenedy County, TX, Kleberg County, TX, Nueces County, TX, Starr County, TX, Webb County, TX, Willacy County, TX, Zapata County, TX

The radar

The Corpus Christi radar (KCRP), 141 km from the middle of the area, began a volume at 18:32 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.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 6.5 hours before the alert went out and 149 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, Corpus Christi, TX at 12:00Z on 2012-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 633 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, Corpus Christi, TX at 12:00Z on 2012-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 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
633 J/kg
Mixed-layer CIN
-475 J/kg
Mixed-layer LCL
1213 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
47 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
Apr 19, 9:13 PM CDTMesoscale DiscussionSPCCooke, Denton, Grayson, Jack, Montague, Wise62 min
Apr 19, 10:49 PM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Cooke, Foard, Hardeman and 7 more116 min
Apr 20, 12:35 PM CDTMesoscale DiscussionSPCAngelina, Aransas, Austin, Bee, Brazoria, Calhoun and 33 more2 hr
Apr 20, 12:57 PM CDTSevere Thunderstorm WatchSPCAransas, Austin, Bastrop, Bee, Brazoria, Brazos and 43 more7 hr
Apr 20, 2:29 PM CDTSevere Thunderstorm WatchSPCBrooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 10 more5 hr
Apr 20, 3:44 PM CDTMesoscale DiscussionSPCAngelina, Austin, Brazoria, Brazos, Burleson, Chambers and 27 more91 min
Apr 20, 4:48 PM CDTMesoscale DiscussionSPCBrooks, Cameron, Hidalgo, Kenedy, Kleberg, Nueces and 2 more57 min
Apr 20, 6:12 PM CDTMesoscale DiscussionSPCAransas, Brazoria, Calhoun, Chambers, Fort Bend, Galveston and 18 more93 min

Nearby

Mesoscale Discussions in Texas, 2012Every mesoscale discussion in 2012

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.