Alert archive / Alabama / Mesoscale Discussions in 2007

Mesoscale Discussion 490

April 14, 200716 counties in Alabama; 14 counties in Georgia; 12 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2007, 12:24 PM CDT for 16 counties in Alabama; 14 counties in Georgia; 12 counties in Tennessee. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: Apr 14, 2007, 12:24 PM CDT (17:24 UTC)
Expired: Apr 14, 2007, 1:30 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center

All 42 counties

Blount County, AL, Calhoun County, AL, Cherokee County, AL, Cleburne County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Jackson County, AL, Jefferson County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, St. Clair County, AL, Talladega County, AL, Walker County, AL, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Haralson County, GA, Murray County, GA, Pickens County, GA, Polk County, GA, Walker County, GA, Whitfield County, GA, Bledsoe County, TN, Bradley County, TN, Franklin County, TN, Grundy County, TN, Hamilton County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Polk County, TN, Rhea County, TN, Sequatchie County, TN

The radar

The Northeast Alabama radar (KHTX), 74 km from the middle of the area, began a volume at 17:27 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

Birmingham, AL (KBMX), launched 12:00Z, 5.4 hours before the alert went out and 140 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 972 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 238 m²/s²
0-3 km storm-relative helicity: 289 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

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 14, 10:07 AM CDT	Mesoscale Discussion	SPC	Baldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 7 more	53 min
Apr 14, 10:26 AM CDT	Tornado Watch	SPC	Autauga, Baldwin, Barbour, Bibb, Bullock, Butler and 32 more	7 hr
Apr 14, 2:12 PM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Barbour, Bibb, Bullock, Butler and 32 more	63 min
Apr 14, 3:35 PM CDT	Tornado Watch	SPC	Coffee, Dale, Geneva, Henry, Houston	7 hr
Apr 14, 5:04 PM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Bibb, Bullock, Butler, Chambers and 26 more	56 min
Apr 14, 5:26 PM CDT	Tornado Watch	SPC	Autauga, Baldwin, Barbour, Bullock, Butler, Choctaw and 19 more	6 hr
Apr 14, 2:40 PM CDT	Mesoscale Discussion	SPC	Atkinson, Bacon, Baker, Baldwin, Ben Hill, Berrien and 73 more	65 min
Apr 14, 4:53 PM CDT	Mesoscale Discussion	SPC	Appling, Brantley, Bryan, Bulloch, Camden, Candler and 11 more	97 min

Nearby

Mesoscale Discussions in Alabama, 2007 Mesoscale Discussions in Georgia, 2007 Mesoscale Discussions in Tennessee, 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.