Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 729

May 6, 20096 states

The Storm Prediction Center issued this mesoscale discussion at May 6, 2009, 7:22 AM CDT for 6 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
May 6, 2009, 7:22 AM CDT (12:22 UTC)
Expired
May 6, 2009, 8:45 AM CDT
In force
83 min
Issued by
the Storm Prediction Center
All 68 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marengo County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Ashley County, AR, Chattooga County, GA, Dade County, GA, Floyd County, GA, Haralson County, GA, Polk County, GA, East Carroll Parish, LA, Madison Parish, LA, Morehouse Parish, LA, West Carroll Parish, LA, Attala County, MS, Clarke County, MS, Hinds County, MS, Issaquena County, MS, Jasper County, MS, Kemper County, MS, Lauderdale County, MS, Leake County, MS, Lowndes County, MS, Madison County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Warren County, MS, Winston County, MS, Yazoo County, MS, Giles County, TN, Lincoln County, TN

The radar

The Columbus AFB radar (KGWX), 79 km from the middle of the area, began a volume at 12:24 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

Jackson, MS (KJAN), launched 12:00Z, 0.4 hours before the alert went out and 163 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, Jackson, MS at 12:00Z on 2009-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2140 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, Jackson, MS at 12:00Z on 2009-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 251 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
2140 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
510 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
251 m²/s²
0-3 km storm-relative helicity
271 m²/s²
Significant tornado parameter
2.9
Supercell composite
10.8

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
May 5, 11:45 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Colbert, Cullman, Etowah, Fayette and 13 more90 min
May 6, 1:27 AM CDTMesoscale DiscussionSPCBlount, Cullman, Fayette, Franklin, Jefferson, Lamar and 4 more3 hr
May 6, 3:05 AM CDTMesoscale DiscussionSPCFayette, Jefferson, Lamar, Marion, Pickens, Tuscaloosa and 1 more115 min
May 6, 4:03 AM CDTSevere Thunderstorm WatchSPCBibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 27 more6 hr
May 6, 6:58 AM CDTMesoscale DiscussionSPCGreene, Pickens, Sumter3 hr
May 6, 9:04 AM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Bullock, Butler, Calhoun and 27 more56 min
May 6, 9:27 AM CDTTornado WatchSPCAutauga, Barbour, Bibb, Blount, Bullock, Calhoun and 31 more9 hr
May 6, 12:37 PM CDTSevere Thunderstorm WatchSPCButler, Choctaw, Clarke, Conecuh, Covington, Crenshaw and 4 more6 hr
May 6, 1:57 PM CDTMesoscale DiscussionSPCBullock, Russell93 min
May 6, 4:47 PM CDTMesoscale DiscussionSPCDale, Geneva, Henry58 min
May 5, 10:07 PM CDTMesoscale DiscussionSPCArkansas, Calhoun, Clark, Cleveland, Conway, Crittenden and 28 more83 min
May 5, 10:27 PM CDTSevere Thunderstorm WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 49 more8 hr
May 5, 11:26 PM CDTSevere Thunderstorm WatchSPCSebastian6 hr
May 6, 12:53 AM CDTMesoscale DiscussionSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Dallas and 14 more37 min
May 6, 12:54 AM CDTTornado WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 20 more5 hr
May 6, 2:00 AM CDTMesoscale DiscussionSPCSebastian2 hr
May 6, 2:26 AM CDTMesoscale DiscussionSPCCleburne, Conway, Craighead, Crittenden, Cross, Faulkner and 23 more2 hr
May 6, 5:29 AM CDTSevere Thunderstorm WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more8 hr
May 6, 5:45 AM CDTSevere Thunderstorm WatchSPCAshley, Bradley, Calhoun, Chicot, Cleveland, Desha and 3 more7 hr
May 6, 7:47 AM CDTMesoscale DiscussionSPCBanks, Barrow, Clarke, Columbia, Elbert, Franklin and 17 more88 min
May 6, 5:08 AM CDTMesoscale DiscussionSPCBossier, Caddo, De Soto97 min
May 6, 11:34 AM CDTMesoscale DiscussionSPCTensas86 min

Nearby

Mesoscale Discussions in Alabama, 2009Mesoscale Discussions in Mississippi, 2009Mesoscale Discussions in Georgia, 2009Every mesoscale discussion in 2009

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.