Alert archive / Mississippi / Mesoscale Discussions in 2006

Mesoscale Discussion 591

April 20, 20065 counties in Arkansas; 32 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2006, 7:35 PM CDT for 5 counties in Arkansas; 32 counties in Mississippi. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2006, 7:35 PM CDT (00:35 UTC)
Expired
Apr 20, 2006, 9:00 PM CDT
In force
85 min
Issued by
the Storm Prediction Center
All 37 counties

Arkansas County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Coahoma County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Monroe County, MS, Montgomery County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tippah County, MS, Union County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS

The radar

The Columbus AFB radar (KGWX), 124 km from the middle of the area, began a volume at 00:36 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 (KLZK), launched 00:00Z, 0.6 hours before the alert went out and 113 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 2006-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 512 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 2006-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 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
512 J/kg
Mixed-layer CIN
-90 J/kg
Mixed-layer LCL
1181 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
130 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 9:31 PM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Craighead and 29 more89 min
Apr 20, 10:00 PM CDTSevere Thunderstorm WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 33 more7 hr
Apr 21, 2:15 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Chicot, Desha, Drew and 5 more2 hr
Apr 21, 12:04 AM CDTMesoscale DiscussionSPCAlcorn, Benton, Itawamba, Lafayette, Lee, Marshall and 8 more116 min
Apr 21, 5:00 AM CDTMesoscale DiscussionSPCAlcorn, Benton, Calhoun, Chickasaw, DeSoto, Itawamba and 12 more60 min
Apr 21, 9:51 AM CDTMesoscale DiscussionSPCAdams, Amite, Attala, Claiborne, Copiah, Covington and 25 more84 min
Apr 21, 10:16 AM CDTSevere Thunderstorm WatchSPCAdams, Amite, Claiborne, Clarke, Copiah, Covington and 27 more6 hr
Apr 21, 12:52 PM CDTMesoscale DiscussionSPCAmite, Clarke, Copiah, Covington, Forrest, George and 26 more83 min
Apr 21, 1:24 PM CDTSevere Thunderstorm WatchSPCClay, George, Greene, Harrison, Jackson, Lowndes and 6 more8 hr

Nearby

Mesoscale Discussions in Mississippi, 2006Mesoscale Discussions in Arkansas, 2006Every mesoscale discussion in 2006

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.