Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 701

May 4, 200913 counties in Alabama

The Storm Prediction Center issued this mesoscale discussion at May 4, 2009, 3:24 PM CDT for 13 counties in Alabama. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 4, 2009, 3:24 PM CDT (20:24 UTC)
Expired: May 4, 2009, 4:30 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center

Counties Bibb County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Coosa County, AL, Dallas County, AL, Hale County, AL, Marengo County, AL, Perry County, AL, Randolph County, AL, Shelby County, AL, Talladega County, AL

The radar

The Birmingham radar (KBMX), 87 km from the middle of the area, began a volume at 20:27 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, 8.4 hours before the alert went out and 87 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: 132 J/kg
Mixed-layer CIN: -76 J/kg
Mixed-layer LCL: 546 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 206 m²/s²
0-3 km storm-relative helicity: 310 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.1

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
May 4, 1:30 AM CDT	Mesoscale Discussion	SPC	Barbour, Bullock, Butler, Choctaw, Clarke, Coffee and 13 more	3 hr
May 4, 2:12 AM CDT	Mesoscale Discussion	SPC	Baldwin, Coffee, Covington, Dale, Escambia, Geneva and 2 more	93 min
May 4, 2:34 AM CDT	Tornado Watch	SPC	Baldwin, Butler, Clarke, Conecuh, Covington, Crenshaw and 5 more	5 hr
May 4, 4:58 AM CDT	Mesoscale Discussion	SPC	Baldwin, Barbour, Butler, Clarke, Coffee, Conecuh and 10 more	2 hr
May 4, 7:33 AM CDT	Tornado Watch	SPC	Baldwin, Butler, Coffee, Conecuh, Covington, Crenshaw and 6 more	6 hr
May 4, 10:38 AM CDT	Mesoscale Discussion	SPC	Barbour, Dale, Geneva, Henry, Houston	67 min
May 4, 1:34 PM CDT	Mesoscale Discussion	SPC	Baldwin, Coffee, Conecuh, Covington, Dale, Escambia and 2 more	56 min

Nearby

Mesoscale Discussions in Alabama, 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.