Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 744

May 7, 200913 counties in Alabama; 8 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at May 7, 2009, 1:21 PM CDT for 13 counties in Alabama; 8 counties in Georgia. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
May 7, 2009, 1:21 PM CDT (18:21 UTC)
Expired
May 7, 2009, 2:15 PM CDT
In force
54 min
Issued by
the Storm Prediction Center
All 21 counties

Barbour County, AL, Bullock County, AL, Butler County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lowndes County, AL, Pike County, AL, Calhoun County, GA, Clay County, GA, Decatur County, GA, Early County, GA, Miller County, GA, Quitman County, GA, Randolph County, GA, Seminole County, GA

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 6.4 hours before the alert went out and 193 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-pSkew-T log-p diagram, Birmingham, AL at 12:00Z on 2009-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1258 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 12:00Z on 2009-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1258 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
446 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
115 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.2

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.

IssuedProductOfficeCountiesLasted
May 7, 7:47 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bullock, Dallas, Henry, Lowndes and 3 more58 min
May 6, 10:44 PM CDTMesoscale DiscussionSPCCatoosa, Dawson, Fannin, Gilmer, Gordon, Habersham and 9 more91 min

Nearby

Mesoscale Discussions in Alabama, 2009Mesoscale Discussions in Georgia, 2009Every 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.