Alert archive / Alabama / Mesoscale Discussions in 2009

Mesoscale Discussion 688

May 3, 200928 counties in Alabama; 21 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at May 3, 2009, 1:49 PM CDT for 28 counties in Alabama; 21 counties in Georgia. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
May 3, 2009, 1:49 PM CDT (18:49 UTC)
Expired
May 3, 2009, 2:45 PM CDT
In force
56 min
Issued by
the Storm Prediction Center
All 49 counties

Autauga County, AL, Bibb County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Conecuh County, AL, Coosa County, AL, Crenshaw County, AL, Dallas County, AL, Elmore County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Wilcox County, AL, Bartow County, GA, Carroll County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Floyd County, GA, Fulton County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Henry County, GA, Meriwether County, GA, Paulding County, GA, Pike County, GA, Polk County, GA, Rockdale County, GA, Spalding County, GA, Troup County, GA

The radar

The Birmingham radar (KBMX), 59 km from the middle of the area, began a volume at 18:52 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.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 6.8 hours before the alert went out and 60 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 2009-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 365 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 2009-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 193 square meters per square second.19395878Sfc1 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
365 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
527 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
193 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.4
Supercell composite
2.0

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 2, 7:30 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Clay, Cullman, Etowah and 12 more60 min
May 2, 8:43 PM CDTTornado WatchSPCBibb, Blount, Chilton, Fayette, Greene, Hale and 9 more6 hr
May 2, 10:40 PM CDTMesoscale DiscussionSPCBibb, Greene, Hale, Jefferson, Pickens, Tuscaloosa2 hr
May 3, 7:18 AM CDTMesoscale DiscussionSPCBibb, Chilton, Fayette, Greene, Hale, Jefferson and 6 more57 min
May 3, 7:44 AM CDTSevere Thunderstorm WatchSPCBibb, Chilton, Fayette, Greene, Hale, Jefferson and 8 more8 hr
May 3, 9:24 AM CDTMesoscale DiscussionSPCChoctaw, Greene, Hale, Lamar, Marengo, Perry and 3 more66 min
May 3, 10:56 AM CDTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Calhoun and 39 more64 min
May 3, 11:35 AM CDTSevere Thunderstorm WatchSPCAutauga, Baldwin, Barbour, Blount, Bullock, Butler and 29 more5 hr
May 3, 3:11 PM CDTSevere Thunderstorm WatchSPCCoffee, Dale, Geneva, Henry, Houston3 hr
May 3, 3:13 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Calhoun, Chambers, Cherokee, Clay and 16 more62 min
May 3, 5:36 PM CDTMesoscale DiscussionSPCHenry84 min
May 3, 3:42 PM CDTSevere Thunderstorm WatchSPCBaldwin, Banks, Barrow, Bartow, Bibb, Bleckley and 90 more4 hr
May 3, 6:29 PM CDTSevere Thunderstorm WatchSPCColumbia, Elbert, Franklin, Habersham, Hart, Lincoln and 3 more2 hr

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; radar from the NEXRAD Level II archive.