Alert archive / Alabama / Mesoscale Discussions in 2008

Mesoscale Discussion 821

May 8, 200810 counties in Alabama; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 8, 2008, 12:13 PM CDT for 10 counties in Alabama; 5 counties in Mississippi. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: May 8, 2008, 12:13 PM CDT (17:13 UTC)
Expired: May 8, 2008, 1:45 PM CDT
In force: 92 min
Issued by: the Storm Prediction Center

Counties Bibb County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, Sumter County, AL, Tuscaloosa County, AL, Kemper County, MS, Lauderdale County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS

The radar

The Columbus AFB radar (KGWX), 102 km from the middle of the area, began a volume at 17:14 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.

Tornado Watch 278May 8, 12:40 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 5.2 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-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: 212 J/kg
Mixed-layer CIN: -132 J/kg
Mixed-layer LCL: 567 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 193 m²/s²
0-3 km storm-relative helicity: 216 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
ACUS11 KWNS 081714
SWOMCD
SPC MCD 081713 
ALZ000-MSZ000-081845-

MESOSCALE DISCUSSION 0821
NWS STORM PREDICTION CENTER NORMAN OK
1213 PM CDT THU MAY 08 2008

AREAS AFFECTED...E CNTRL MS INTO W CNTRL AL

CONCERNING...TORNADO WATCH 277...

VALID 081713Z - 081845Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 277 CONTINUES.

AN ADDITIONAL WW PROBABLY WILL BE NEEDED EARLY THIS AFTERNOON.

CONVECTIVE CELLS CONTINUE TO SLOWLY DEEPEN ACROSS SOUTHWEST THROUGH
EAST CENTRAL MISSISSIPPI...ALONG/JUST AHEAD OF THE SOUTHERN FLANK OF
ONGOING SQUALL LINE NOW ADVANCING TOWARD THE UPPER TENNESSEE VALLEY.
 THE BOUNDARY LAYER INSTABILITY IS STILL RATHER MODEST... ON THE
ORDER OF 1000 J/KG...AND THIS...COUPLED WITH SUBSIDENCE WARMING
ALOFT...IS SLOWING STORM INTENSIFICATION.  LATEST RUC GUIDANCE NOW
SUGGESTS THAT INHIBITION FOR BOUNDARY LAYER PARCELS IS SMALL ACROSS
MUCH OF CENTRAL/SOUTHERN MISSISSIPPI AND ALABAMA.  BUT...POTENTIAL
FOR VIGOROUS STORM INITIATION SEEMS MOST PROBABLE ACROSS EAST
CENTRAL MISSISSIPPI INTO CENTRAL ALABAMA...WHERE MID-LEVEL
TEMPERATURES REMAIN COOLER ASSOCIATED WITH LINGERING INFLUENCE OF
UPPER IMPULSE NOW LIFTING THROUGH KENTUCKY/TENNESSEE.  THIS STILL
APPEARS POSSIBLE NEAR/NORTH OF MERIDIAN INTO AREAS NEAR/SOUTH OF
TUSCALOOSA/BIRMINGHAM BY 18-19Z.  AND...WITHIN THE PRESENCE OF
STRONG DEEP LAYER SHEAR AND LARGE CLOCKWISE CURVED LOW-LEVEL
HODOGRAPHS NEAR A 40-50 KT LOW-LEVEL JET AXIS...THE RISK FOR
DISCRETE SUPERCELLS WITH TORNADOES WILL INCREASE.  ISOLATED STRONG
TORNADOES ARE POSSIBLE.

..KERR.. 05/08/2008

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...MOB...JAN...

32648932 33078898 33488837 33788771 33788713 33648654
33398646 32928685 32468749 32058867 32388925

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 8, 7:48 AM CDT	Mesoscale Discussion	SPC	Colbert, Fayette, Franklin, Lamar, Lawrence, Marion and 3 more	87 min
May 8, 8:04 AM CDT	Tornado Watch	SPC	Colbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 9 more	6 hr
May 8, 10:07 AM CDT	Mesoscale Discussion	SPC	Autauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 33 more	83 min
May 8, 12:37 PM CDT	Mesoscale Discussion	SPC	Blount, Cherokee, Cullman, DeKalb, Etowah, Jackson and 7 more	83 min
May 8, 12:40 PM CDT	Tornado Watch	SPC	Bibb, Blount, Calhoun, Cherokee, Chilton, Choctaw and 29 more	5 hr
May 8, 3:13 PM CDT	Mesoscale Discussion	SPC	Autauga, Bibb, Calhoun, Chambers, Cherokee, Chilton and 17 more	2 hr
May 7, 10:28 PM CDT	Mesoscale Discussion	SPC	Adams	92 min
May 7, 11:49 PM CDT	Mesoscale Discussion	SPC	Adams, Amite, Claiborne, Copiah, Covington, Franklin and 25 more	116 min

Nearby

Mesoscale Discussions in Alabama, 2008 Mesoscale Discussions in Mississippi, 2008 Every mesoscale discussion in 2008

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.