Alert archive / Mississippi / Mesoscale Discussions in 2009

Mesoscale Discussion 677

May 2, 200918 counties in Alabama; 30 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 2, 2009, 7:30 PM CDT for 18 counties in Alabama; 30 counties in Mississippi. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued
May 2, 2009, 7:30 PM CDT (00:30 UTC)
Expired
May 2, 2009, 8:30 PM CDT
In force
60 min
Issued by
the Storm Prediction Center
All 48 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Clay County, AL, Cullman County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Lamar County, AL, Marion County, AL, Marshall County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Pontotoc County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Columbus AFB radar (KGWX), 57 km from the middle of the area, began a volume at 00:30 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 00:00Z, 0.5 hours before the alert went out and 174 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 00:00Z on 2009-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 495 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 00:00Z on 2009-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 83 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
495 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
1219 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
83 m²/s²
0-3 km storm-relative helicity
113 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.1

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.

IssuedProductOfficeCountiesLasted
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, 1:49 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Butler, Calhoun, Chambers and 22 more56 min
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, 2:39 AM CDTMesoscale DiscussionSPCIssaquena, Washington2 hr
May 3, 6:54 AM CDTMesoscale DiscussionSPCAdams, Amite, Claiborne, Franklin, Jefferson, Warren and 1 more2 hr

Nearby

Mesoscale Discussions in Mississippi, 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; radar from the NEXRAD Level II archive.