Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 610

April 30, 2017Ashley County, Chicot County, Arkansas; 22 parishes in Louisiana; 10 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2017, 6:12 AM CDT for Ashley County, Chicot County, Arkansas; 22 parishes in Louisiana; 10 counties in Mississippi. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
Apr 30, 2017, 6:12 AM CDT (11:12 UTC)
Expired
Apr 30, 2017, 7:45 AM CDT
In force
93 min
Issued by
the Storm Prediction Center
All 34 counties

Ashley County, AR, Chicot County, AR, Acadia Parish, LA, Avoyelles Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Franklin Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Lafayette Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Pointe Coupee Parish, LA, Richland Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tensas Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Franklin County, MS, Issaquena County, MS, Jefferson County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS

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 00:00Z, 11.2 hours before the alert went out and 180 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 00:00Z on 2017-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3254 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 00:00Z on 2017-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 198 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
3254 J/kg
Mixed-layer CIN
-63 J/kg
Mixed-layer LCL
602 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
198 m²/s²
0-3 km storm-relative helicity
251 m²/s²
Significant tornado parameter
3.4
Supercell composite
26.7

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
Apr 29, 9:38 PM CDTMesoscale DiscussionSPCClark, Columbia, Hempstead, Hot Spring, Howard, Lafayette and 5 more67 min
Apr 29, 10:23 PM CDTSevere Thunderstorm WatchSPCArkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 36 more8 hr
Apr 29, 11:37 PM CDTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleveland, Columbia, Conway and 23 more53 min
Apr 30, 12:54 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clay and 26 more96 min
Apr 30, 1:10 AM CDTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lee and 4 more6 hr
Apr 30, 1:49 AM CDTTornado WatchSPCAshley, Chicot7 hr
Apr 30, 2:58 AM CDTMesoscale DiscussionSPCCrittenden, Cross, Lee, Mississippi, Phillips, Poinsett and 1 more92 min
Apr 30, 3:36 AM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Cleveland, Desha, Drew and 10 more84 min
Apr 30, 5:41 AM CDTMesoscale DiscussionSPCArkansas, Bradley, Clay, Cleveland, Craighead, Crittenden and 19 more64 min
Apr 30, 1:14 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 20 more91 min
Apr 30, 6:59 AM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Jefferson, Lafourche and 12 more2 hr
Apr 30, 7:32 AM CDTTornado WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 14 more7 hr
Apr 30, 10:06 AM CDTMesoscale DiscussionSPCChickasaw, Itawamba, Lee, Monroe, Pontotoc, Prentiss and 2 more84 min
Apr 30, 10:36 AM CDTTornado WatchSPCAlcorn, Benton, Calhoun, Chickasaw, Itawamba, Lafayette and 9 more8 hr

Nearby

Mesoscale Discussions in Louisiana, 2017Mesoscale Discussions in Mississippi, 2017Mesoscale Discussions in Arkansas, 2017Every mesoscale discussion in 2017

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.