Alert archive / Mississippi / Mesoscale Discussions in 2009

Mesoscale Discussion 791

May 10, 20096 counties in Alabama; Concordia Parish, Grant Parish, Louisiana; 16 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 10, 2009, 7:29 PM CDT for 6 counties in Alabama; Concordia Parish, Grant Parish, Louisiana; 16 counties in Mississippi. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: May 10, 2009, 7:29 PM CDT (00:29 UTC)
Expired: May 10, 2009, 8:30 PM CDT
In force: 61 min
Issued by: the Storm Prediction Center

All 24 counties

Choctaw County, AL, Clarke County, AL, Marengo County, AL, Monroe County, AL, Washington County, AL, Wilcox County, AL, Concordia Parish, LA, Grant Parish, LA, Adams County, MS, Amite County, MS, Clarke County, MS, Covington County, MS, Franklin County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lauderdale County, MS, Lawrence County, MS, Lincoln County, MS, Newton County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Wayne County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 85 km from the middle of the area, began a volume at 00:32 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 287May 10, 7:50 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 0.5 hours before the alert went out and 94 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: 1666 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 1226 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 101 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 7.4

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
May 10, 7:50 PM CDT	Severe Thunderstorm Watch	SPC	Choctaw, Clarke, Conecuh, Dallas, Greene, Hale and 6 more	5 hr
May 10, 11:45 PM CDT	Mesoscale Discussion	SPC	Autauga, Barbour, Bullock, Butler, Coffee, Conecuh and 12 more	90 min
May 11, 1:05 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 11 more	85 min
May 11, 2:20 PM CDT	Mesoscale Discussion	SPC	Allen, Avoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana and 13 more	55 min
May 11, 2:52 PM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 21 more	5 hr
May 11, 6:15 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Iberville, Livingston, Saint Charles, Saint James and 2 more	90 min

Nearby

Mesoscale Discussions in Mississippi, 2009 Mesoscale Discussions in Alabama, 2009 Mesoscale Discussions in Louisiana, 2009 Every 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.