Alert archive / Mississippi / Mesoscale Discussions in 2007

Mesoscale Discussion 454

April 11, 200715 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2007, 7:30 AM CDT for 15 counties in Mississippi. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Apr 11, 2007, 7:30 AM CDT (12:30 UTC)
Expired: Apr 11, 2007, 8:30 AM CDT
In force: 60 min
Issued by: the Storm Prediction Center

Counties Attala County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Itawamba County, MS, Lee County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Pontotoc County, MS, Webster County, MS

The radar

The Columbus AFB radar (KGWX), 106 km from the middle of the area, began a volume at 12:32 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

Jackson, MS (KJAN), launched 12:00Z, 0.5 hours before the alert went out and 143 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 441 J/kg
Mixed-layer CIN: -84 J/kg
Mixed-layer LCL: 605 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 327 m²/s²
0-3 km storm-relative helicity: 367 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 1.3

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.

Issued	Product	Office	Counties	Lasted
Apr 11, 2:19 AM CDT	Mesoscale Discussion	SPC	Bolivar, Coahoma, Humphreys, Issaquena, Leflore, Quitman and 4 more	116 min
Apr 11, 2:56 AM CDT	Severe Thunderstorm Watch	SPC	Attala, Benton, Bolivar, Calhoun, Carroll, Chickasaw and 29 more	5 hr
Apr 11, 4:36 AM CDT	Mesoscale Discussion	SPC	Attala, Benton, Calhoun, Carroll, Chickasaw, Choctaw and 26 more	114 min
Apr 11, 12:16 PM CDT	Mesoscale Discussion	SPC	Alcorn, Attala, Chickasaw, Choctaw, Clarke, Clay and 19 more	59 min
Apr 11, 1:42 PM CDT	Tornado Watch	SPC	Clarke, Jasper, Kemper, Lauderdale, Lowndes, Neshoba and 3 more	5 hr

Nearby

Mesoscale Discussions in Mississippi, 2007 Every mesoscale discussion in 2007

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.