Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 482

April 27, 201514 parishes in Louisiana; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2015, 1:08 PM CDT for 14 parishes in Louisiana; 15 counties in Texas. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2015, 1:08 PM CDT (18:08 UTC)
Expired
Apr 27, 2015, 2:45 PM CDT
In force
97 min
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 29 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Jefferson Davis Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Vernon Parish, LA, Angelina County, TX, Chambers County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Trinity County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 81 km from the middle of the area, began a volume at 18:11 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 6.1 hours before the alert went out and 82 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, Lake Charles Mun, LA at 12:00Z on 2015-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2462 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, Lake Charles Mun, LA at 12:00Z on 2015-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 189 square meters per square second.1939587897Sfc1 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
2462 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
722 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
189 m²/s²
0-3 km storm-relative helicity
364 m²/s²
Significant tornado parameter
6.1
Supercell composite
23.1

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 27, 1:27 AM CDTTornado WatchSPCBossier, Caddo, De Soto, Sabine6 hr
Apr 27, 4:56 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 15 more2 hr
Apr 27, 6:01 AM CDTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 36 more7 hr
Apr 27, 7:44 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, East Baton Rouge and 26 more91 min
Apr 27, 9:47 AM CDTMesoscale DiscussionSPCJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 6 more88 min
Apr 26, 7:10 PM CDTMesoscale DiscussionSPCArcher, Baylor, Carson, Childress, Clay, Collingsworth and 14 more65 min
Apr 26, 7:59 PM CDTSevere Thunderstorm WatchSPCBandera, Bexar, Blanco, Brown, Burnet, Coleman and 24 more6 hr
Apr 26, 9:29 PM CDTMesoscale DiscussionSPCDallas, Ellis, Hood, Hunt, Johnson, Kaufman and 4 more91 min
Apr 26, 10:45 PM CDTTornado WatchSPCAnderson, Bell, Bosque, Comanche, Coryell, Ellis and 19 more5 hr
Apr 27, 12:49 AM CDTMesoscale DiscussionSPCAnderson, Angelina, Atascosa, Austin, Bastrop, Bexar and 49 more86 min
Apr 27, 3:42 AM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Cooke, Denton, Foard and 12 more93 min
Apr 27, 5:25 AM CDTMesoscale DiscussionSPCBrooks, Kenedy95 min
Apr 27, 3:29 PM CDTMesoscale DiscussionSPCAustin, Bastrop, Bell, Bosque, Brazos, Burleson and 22 more91 min

Nearby

Mesoscale Discussions in Texas, 2015Mesoscale Discussions in Louisiana, 2015Every mesoscale discussion in 2015

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.