Alert archive / Texas / Mesoscale Discussions in 2018

Mesoscale Discussion 187

March 28, 201813 parishes in Louisiana; 16 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2018, 11:38 AM CDT for 13 parishes in Louisiana; 16 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Mar 28, 2018, 11:38 AM CDT (16:38 UTC)
Expired
Mar 28, 2018, 12:45 PM CDT
In force
67 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 29 counties

Beauregard Parish, LA, Caldwell Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Richland Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Winn Parish, LA, Austin County, TX, Colorado County, TX, Fort Bend County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Liberty County, TX, Montgomery County, TX, Newton County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Tyler County, TX, Waller County, TX, Wharton County, TX

The radar

The Ft Polk radar (KPOE), 87 km from the middle of the area, began a volume at 16:41 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 4.6 hours before the alert went out and 127 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 2018-03-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 295 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 2018-03-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 159 square meters per square second.19395878Sfc1 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
295 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
650 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
159 m²/s²
0-3 km storm-relative helicity
215 m²/s²
Significant tornado parameter
0.2
Supercell composite
3.6

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 28, 12:03 PM CDTTornado WatchSPCAllen, Avoyelles, Beauregard, Bienville, Calcasieu, Caldwell and 12 more9 hr
Mar 28, 2:43 PM CDTMesoscale DiscussionSPCEast Carroll, Franklin, Madison, Morehouse, Richland, Tensas and 1 more92 min
Mar 28, 3:07 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Caldwell, Grant, Jackson, LaSalle and 4 more113 min
Mar 28, 3:27 PM CDTTornado WatchSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more8 hr
Mar 28, 5:32 PM CDTMesoscale DiscussionSPCMadison, Tensas118 min
Mar 28, 5:48 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, Evangeline, Grant, LaSalle and 2 more87 min
Mar 27, 9:23 PM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Blanco, Caldwell, Comal and 20 more97 min
Mar 27, 9:51 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bastrop, Bexar, Caldwell, DeWitt, Dimmit and 15 more5 hr
Mar 27, 11:58 PM CDTMesoscale DiscussionSPCAtascosa, Bastrop, Bexar, Caldwell, Comal, DeWitt and 17 more2 hr
Mar 28, 5:05 AM CDTMesoscale DiscussionSPCBastrop, Brazos, Burleson, Fayette, Grimes, Lee and 1 more85 min
Mar 28, 9:09 AM CDTMesoscale DiscussionSPCAtascosa, Bexar, Frio, Medina, Wilson2 hr
Mar 28, 6:53 PM CDTMesoscale DiscussionSPCBrooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 6 more97 min

Nearby

Mesoscale Discussions in Texas, 2018Mesoscale Discussions in Louisiana, 2018Every mesoscale discussion in 2018

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.