Alert archive / Mississippi / Mesoscale Discussions in 2011
Mesoscale Discussion 499
The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2011, 10:22 PM CDT for 4 states. It was in force for 83 min.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2011, 10:22 PM CDT (03:22 UTC)
- Expired
- Apr 20, 2011, 11:45 PM CDT
- In force
- 83 min
- Issued by
- the Storm Prediction Center
All 44 counties
Bibb County, AL, Blount County, AL, Cullman County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Ashley County, AR, Bradley County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, West Carroll Parish, LA, Attala County, MS, Bolivar County, MS, Carroll County, MS, Choctaw County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Kemper County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Sharkey County, MS, Sunflower County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yazoo County, MS
The nearest sounding before it
Little Rock, AR (KLZK), launched 00:00Z, 3.4 hours before the alert went out and 157 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 749 m above ground
- 0-6 km bulk shear
- 68 kt
- 0-1 km storm-relative helicity
- 44 m²/s²
- 0-3 km storm-relative helicity
- 240 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 7:45 PM CDT | Severe Thunderstorm Watch | SPC | Bibb, Blount, Calhoun, Cherokee, Cleburne, Etowah and 15 more | 6 hr |
| Apr 21, 2:25 PM CDT | Mesoscale Discussion | SPC | Benton, Clark, Conway, Crawford, Dallas, Franklin and 19 more | 65 min |
| Apr 21, 2:35 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Benton, Boone, Carroll, Clark, Conway and 22 more | 7 hr |
| Apr 21, 6:13 PM CDT | Mesoscale Discussion | SPC | Benton, Crawford, Franklin, Garland, Johnson, Logan and 7 more | 92 min |
| Apr 21, 10:00 AM CDT | Mesoscale Discussion | SPC | Caldwell, Catahoula, Concordia, Franklin, Jackson, LaSalle and 4 more | 90 min |
Nearby
Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Arkansas, 2011Every mesoscale discussion in 2011
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.