Alert archive / Georgia / Mesoscale Discussions in 2009

Mesoscale Discussion 535

April 20, 200912 counties in Alabama; 32 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2009, 12:22 AM CDT for 12 counties in Alabama; 32 counties in Georgia. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2009, 12:22 AM CDT (05:22 UTC)
Expired
Apr 20, 2009, 1:15 AM CDT
In force
53 min
Issued by
the Storm Prediction Center
All 44 counties

Bullock County, AL, Butler County, AL, Chambers County, AL, Crenshaw County, AL, Elmore County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Tallapoosa County, AL, Barrow County, GA, Bibb County, GA, Butts County, GA, Chattahoochee County, GA, Clayton County, GA, Coweta County, GA, Crawford County, GA, DeKalb County, GA, Fayette County, GA, Fulton County, GA, Gwinnett County, GA, Harris County, GA, Heard County, GA, Henry County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Marion County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Muscogee County, GA, Newton County, GA, Peach County, GA, Pike County, GA, Rockdale County, GA, Spalding County, GA, Talbot County, GA, Taylor County, GA, Troup County, GA, Upson County, GA, Walton County, GA

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 5.4 hours before the alert went out and 116 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, Peachtre/Fal Fld, GA at 00:00Z on 2009-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 182 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, Peachtre/Fal Fld, GA at 00:00Z on 2009-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 square meters per square second.1939587897117Sfc1 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
182 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
1004 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
248 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.0

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
Apr 19, 7:27 PM CDTMesoscale DiscussionSPCBlount, Cullman, DeKalb, Madison, Marshall, Morgan and 1 more63 min
Apr 19, 8:19 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Calhoun, Chambers, Cherokee and 18 more56 min
Apr 19, 8:45 PM CDTTornado WatchSPCAutauga, Barbour, Bibb, Bullock, Calhoun, Chambers and 22 more4 hr
Apr 19, 10:21 PM CDTMesoscale DiscussionSPCAutauga, Bullock, Calhoun, Chambers, Cherokee, Chilton and 12 more84 min
Apr 19, 7:51 PM CDTTornado WatchSPCBarrow, Bartow, Butts, Carroll, Catoosa, Chattooga and 42 more6 hr
Apr 19, 11:20 PM CDTMesoscale DiscussionSPCElbert, Franklin, Greene, Hart, Lincoln, McDuffie and 4 more55 min
Apr 19, 11:42 PM CDTTornado WatchSPCBaldwin, Banks, Clarke, Columbia, Elbert, Franklin and 19 more5 hr
Apr 20, 1:52 PM CDTMesoscale DiscussionSPCChatham83 min
Apr 20, 2:16 PM CDTSevere Thunderstorm WatchSPCBryan, Chatham, Effingham, Liberty, Long, McIntosh6 hr
Apr 20, 3:55 PM CDTMesoscale DiscussionSPCBryan, Bulloch, Chatham, Effingham, Evans, Liberty and 1 more95 min
Apr 20, 6:36 PM CDTMesoscale DiscussionSPCChatham84 min

Nearby

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