Alert archive / Arkansas / Mesoscale Discussions in 2017

Mesoscale Discussion 602

April 29, 201711 counties in Arkansas; 5 parishes in Louisiana; 10 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2017, 9:38 PM CDT for 11 counties in Arkansas; 5 parishes in Louisiana; 10 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Apr 29, 2017, 9:38 PM CDT (02:38 UTC)
Expired
Apr 29, 2017, 10:45 PM CDT
In force
67 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 26 counties

Clark County, AR, Columbia County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Pike County, AR, Sevier County, AR, Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Sabine Parish, LA, Webster Parish, LA, Bowie County, TX, Cass County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 41 km from the middle of the area, began a volume at 02:40 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

Shreveport, LA (KBAD), launched 00:00Z, 2.6 hours before the alert went out and 48 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, Shreveport, LA at 00:00Z on 2017-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1748 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, Shreveport, LA at 00:00Z on 2017-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 251 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
1748 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
772 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
251 m²/s²
0-3 km storm-relative helicity
454 m²/s²
Significant tornado parameter
3.0
Supercell composite
19.0

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, 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, 6:12 AM CDTMesoscale DiscussionSPCAshley, Chicot93 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 29, 7:34 PM CDTMesoscale DiscussionSPCAnderson, Delta, Fannin, Franklin, Freestone, Henderson and 11 more56 min
Apr 29, 8:57 PM CDTMesoscale DiscussionSPCBastrop, Brazos, Burleson, Caldwell, Fayette, Gonzales and 11 more63 min
Apr 30, 1:25 AM CDTMesoscale DiscussionSPCDallam, Sherman6 hr

Nearby

Mesoscale Discussions in Arkansas, 2017Mesoscale Discussions in Texas, 2017Mesoscale Discussions in Louisiana, 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; radar from the NEXRAD Level II archive.