Alert archive / Arkansas / Mesoscale Discussions in 2017

Mesoscale Discussion 706

May 12, 201726 counties in Arkansas; Morehouse Parish, West Carroll Parish, Louisiana; 4 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 12, 2017, 10:59 AM CDT for 26 counties in Arkansas; Morehouse Parish, West Carroll Parish, Louisiana; 4 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
May 12, 2017, 10:59 AM CDT (15:59 UTC)
Expired
May 12, 2017, 1:30 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 32 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Jefferson County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Phillips County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Union County, AR, Morehouse Parish, LA, West Carroll Parish, LA, Bolivar County, MS, Coahoma County, MS, Sunflower County, MS, Washington County, MS

The radar

The Little Rock radar (KLZK), 93 km from the middle of the area, began a volume at 16:00 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 nearest sounding before it

Little Rock, AR (KBYH), launched 12:00Z, 4.0 hours before the alert went out and 203 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 12:00Z on 2017-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 113 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 12:00Z on 2017-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 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
113 J/kg
Mixed-layer CIN
-95 J/kg
Mixed-layer LCL
678 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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
May 12, 4:24 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 4 more3 hr
May 12, 9:56 AM CDTMesoscale DiscussionSPCAscension, Assumption, Jefferson, Lafourche, Livingston, Orleans and 8 more3 hr
May 12, 10:35 AM CDTSevere Thunderstorm WatchSPCAssumption, Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard and 5 more5 hr
May 12, 1:42 PM CDTMesoscale DiscussionSPCSaint Bernard108 min
May 12, 1:43 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 12 more3 hr

Nearby

Mesoscale Discussions in Arkansas, 2017Mesoscale Discussions in Mississippi, 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.