Alert archive / Arkansas / Mesoscale Discussions in 2018

Mesoscale Discussion 1092

July 19, 201846 counties in Arkansas; Coahoma County, Tunica County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jul 19, 2018, 8:02 PM CDT for 46 counties in Arkansas; Coahoma County, Tunica County, Mississippi. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
Jul 19, 2018, 8:02 PM CDT (01:02 UTC)
Expired
Jul 19, 2018, 10:00 PM CDT
In force
118 min
Issued by
the Storm Prediction Center
All 48 counties

Arkansas County, AR, Baxter County, AR, Clark County, AR, Cleburne County, AR, Cleveland County, AR, Conway County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Faulkner County, AR, Fulton County, AR, Garland County, AR, Grant County, AR, Greene County, AR, Hot Spring County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Jefferson County, AR, Johnson County, AR, Lawrence County, AR, Lee County, AR, Lincoln County, AR, Logan County, AR, Lonoke County, AR, Marion County, AR, Monroe County, AR, Montgomery County, AR, Newton County, AR, Perry County, AR, Phillips County, AR, Poinsett County, AR, Pope County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, Searcy County, AR, Sharp County, AR, St. Francis County, AR, Stone County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Coahoma County, MS, Tunica County, MS

The radar

The Little Rock radar (KLZK), 55 km from the middle of the area, began a volume at 01:03 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

Little Rock, AR (KBYH), launched 00:00Z, 1.0 hours before the alert went out and 193 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, Little Rock, AR at 00:00Z on 2018-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3860 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, Little Rock, AR at 00:00Z on 2018-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
3860 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
1358 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
2.1
Supercell composite
21.5

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
Jul 19, 7:07 PM CDTSevere Thunderstorm WatchSPCBaxter, Boone, Carroll, Cleburne, Fulton, Independence and 10 more3 hr
Jul 19, 8:54 PM CDTSevere Thunderstorm WatchSPCArkansas, Bradley, Calhoun, Clark, Clay, Cleveland and 35 more114 min
Jul 19, 11:21 PM CDTMesoscale DiscussionSPCChicot, Desha, Phillips114 min
Jul 20, 9:25 AM CDTMesoscale DiscussionSPCArkansas, Cleburne, Crittenden, Cross, Faulkner, Independence and 13 more2 hr
Jul 20, 12:58 PM CDTMesoscale DiscussionSPCClay62 min
Jul 20, 3:46 PM CDTMesoscale DiscussionSPCBaxter, Boone, Fulton, Izard, Marion, Randolph and 2 more59 min
Jul 20, 3:58 PM CDTSevere Thunderstorm WatchSPCBaxter, Clay, Craighead, Cross, Fulton, Greene and 8 more6 hr
Jul 20, 5:54 PM CDTMesoscale DiscussionSPCCrittenden, Lee, Phillips, St. Francis3 hr
Jul 20, 6:22 PM CDTTornado WatchSPCCrittenden, Lee, Mississippi, Phillips, St. Francis8 hr
Jul 20, 1:23 PM CDTMesoscale DiscussionSPCAttala, Carroll, Choctaw, Clarke, Copiah, Covington and 20 more97 min
Jul 20, 2:11 PM CDTSevere Thunderstorm WatchSPCClarke, Covington, Forrest, Hinds, Jasper, Jefferson Davis and 14 more3 hr

Nearby

Mesoscale Discussions in Arkansas, 2018Mesoscale Discussions in Mississippi, 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.