Alert archive / Arkansas / Mesoscale Discussions in 2018

Mesoscale Discussion 249

April 13, 20184 states

The Storm Prediction Center issued this mesoscale discussion at Apr 13, 2018, 8:54 PM CDT for 4 states. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Apr 13, 2018, 8:54 PM CDT (01:54 UTC)
Expired
Apr 13, 2018, 10:00 PM CDT
In force
66 min
Issued by
the Storm Prediction Center
All 84 counties

Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Clay County, AR, Cleburne County, AR, Cleveland County, AR, Columbia County, AR, Conway County, AR, Craighead County, AR, Cross County, AR, Dallas County, AR, Faulkner County, AR, Fulton County, AR, Garland County, AR, Grant County, AR, Greene County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Jefferson County, AR, Lafayette County, AR, Lawrence County, AR, Lee County, AR, Lincoln County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Phillips County, AR, Pike County, AR, Poinsett County, AR, Pope County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, Sevier County, AR, Sharp County, AR, St. Francis County, AR, Stone County, AR, Union County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Dunklin County, MO, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Upshur County, TX

The radar

The Little Rock radar (KLZK), 133 km from the middle of the area, began a volume at 01:53 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, 1.9 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, Shreveport, LA at 00:00Z on 2018-04-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1539 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 2018-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 238 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
1539 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
1018 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
238 m²/s²
0-3 km storm-relative helicity
235 m²/s²
Significant tornado parameter
1.4
Supercell composite
13.1

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 13, 7:06 PM CDTMesoscale DiscussionSPCHoward, Montgomery, Yell24 min
Apr 13, 7:22 PM CDTTornado WatchSPCArkansas, Ashley, Chicot, Desha, Drew, Lincoln and 1 more3 hr
Apr 13, 8:36 PM CDTMesoscale DiscussionSPCGarland, Howard, Pike54 min
Apr 13, 9:53 PM CDTTornado WatchSPCArkansas, Baxter, Bradley, Calhoun, Clark, Cleburne and 37 more8 hr
Apr 13, 10:12 PM CDTTornado WatchSPCAshley, Chicot, Clay, Craighead, Crittenden, Cross and 8 more10 hr
Apr 14, 2:10 AM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Desha, Drew and 3 more2 hr
Apr 14, 6:37 AM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 20 more83 min
Apr 14, 6:57 AM CDTTornado WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 22 more7 hr
Apr 13, 8:42 PM CDTMesoscale DiscussionSPCBollinger, Butler, Camden, Cape Girardeau, Carter, Cole and 33 more63 min

Nearby

Mesoscale Discussions in Arkansas, 2018Mesoscale Discussions in Louisiana, 2018Mesoscale Discussions in Texas, 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.