Alert archive / Alabama / Mesoscale Discussions in 2017

Mesoscale Discussion 549

April 22, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2017, 6:40 PM CDT for 4 states. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2017, 6:40 PM CDT (23:40 UTC)
Expired: Apr 22, 2017, 7:45 PM CDT
In force: 65 min
Issued by: the Storm Prediction Center

All 41 counties

Autauga County, AL, Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Dallas County, AL, DeKalb County, AL, Etowah County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Marengo County, AL, Marshall County, AL, Perry County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa 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, Union County, GA, Walker County, GA, Whitfield County, GA, Cherokee County, NC, Bradley County, TN, Polk County, TN

The radar

The Birmingham radar (KBMX), 89 km from the middle of the area, began a volume at 23:43 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, 11.7 hours before the alert went out and 89 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: 1098 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 22, 12:51 PM CDT	Mesoscale Discussion	SPC	Colbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 7 more	114 min
Apr 22, 3:08 PM CDT	Severe Thunderstorm Watch	SPC	Blount, Colbert, Cullman, Fayette, Franklin, Greene and 15 more	4 hr
Apr 22, 4:56 PM CDT	Mesoscale Discussion	SPC	Blount, Colbert, Cullman, DeKalb, Etowah, Fayette and 18 more	64 min
Apr 22, 10:57 AM CDT	Mesoscale Discussion	SPC	Alleghany, Ashe, Caswell, Granville, Person, Rockingham and 6 more	2 hr
Apr 22, 2:17 PM CDT	Severe Thunderstorm Watch	SPC	Alamance, Caswell, Durham, Edgecombe, Forsyth, Franklin and 12 more	4 hr
Apr 22, 3:12 PM CDT	Mesoscale Discussion	SPC	Alamance, Caswell, Durham, Edgecombe, Forsyth, Franklin and 12 more	2 hr

Nearby

Mesoscale Discussions in Alabama, 2017 Mesoscale Discussions in Georgia, 2017 Mesoscale Discussions in Tennessee, 2017 Every mesoscale discussion in 2017

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.