Alert archive / Mississippi / Mesoscale Discussions in 2004

Mesoscale Discussion 430

April 22, 20046 counties in Alabama; 20 counties in Mississippi; Lawrence County, Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2004, 2:36 PM CDT for 6 counties in Alabama; 20 counties in Mississippi; Lawrence County, Tennessee. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2004, 2:36 PM CDT (19:36 UTC)
Expired: Apr 22, 2004, 4:30 PM CDT
In force: 114 min
Issued by: the Storm Prediction Center

All 27 counties

Colbert County, AL, Franklin County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Marion County, AL, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Clay County, MS, Grenada County, MS, Itawamba County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Pontotoc County, MS, Prentiss County, MS, Sunflower County, MS, Tallahatchie County, MS, Tishomingo County, MS, Union County, MS, Webster County, MS, Yalobusha County, MS, Lawrence County, TN

The radar

The Columbus AFB radar (KGWX), 69 km from the middle of the area, began a volume at 19:35 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 nearest sounding before it

Little Rock, AR (KLZK), launched 12:00Z, 7.6 hours before the alert went out and 117 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 584 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: -99 m²/s²
0-3 km storm-relative helicity: -71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

009 
ACUS11 KWNS 221936
SWOMCD
SPC MCD 221936 
ALZ000-TNZ000-MSZ000-222130-

MESOSCALE DISCUSSION 0430
NWS STORM PREDICTION CENTER NORMAN OK
0236 PM CDT THU APR 22 2004

AREAS AFFECTED...NRN MS...NWRN AL...EXTREME SCNTRL TN

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 221936Z - 222130Z

...ISOLATED SUPERCELLS WILL MOVE ACROSS THE REGION...

ISOLATED SUPERCELLS HAVE DEVELOPED WITHIN STRONGER LOW LEVEL
CONVERGENCE...IMMEDIATELY AHEAD OF OLD MCS OUTFLOW FROM EXTREME
SCNTRL TN...ARCING SWWD INTO NRN MS.  THERE APPEARS TO BE SOME
INFLUENCE FROM WEAK WARM ADVECTION BENEATH THE TRAILING END OF
STRONGER LLJ THAT EXTENDS NEWD ACROSS MIDDLE TN INTO KY.  AT ANY
RATE...STRONG BOUNDARY LAYER THERMALS DUE TO STEEP LAPSE RATES AND
SUFFICIENT DEEP LAYER SHEAR EXIST FOR CONTINUED STORM ROTATION AND
ISOLATED LARGE HAIL/DAMAGING WIND THREAT.  ENVIRONMENTAL PARAMETERS
SUGGEST AN ISOLATED TORNADO IS POSSIBLE HOWEVER THE PRIMARY SEVERE
THREATS WILL BE HAIL AND WIND.

OVER THE NEXT FEW HOURS...LLJ WILL INCREASE WEST OF THIS REGION FROM
SERN TX INTO WRN AR.  THIS MAY LIMIT THE LONGEVITY OF ONGOING
ACTIVITY AS CONVERGENCE SHIFTS INTO THE ARKLATX REGION.

..DARROW.. 04/22/2004

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

ATTN...WFO...OHX...BMX...HUN...MEG...JAN...

33559088 34168984 35208788 35258705 34468693 33438850
33239029

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 21, 7:01 PM CDT	Mesoscale Discussion	SPC	Benton, Coahoma, DeSoto, Lafayette, Marshall, Panola and 3 more	119 min
Apr 22, 9:33 AM CDT	Mesoscale Discussion	SPC	Benton, DeSoto, Marshall, Tippah	117 min
Apr 22, 12:49 PM CDT	Mesoscale Discussion	SPC	Bedford, Campbell, Cannon, Cheatham, Clay, Coffee and 34 more	2 hr

Nearby

Mesoscale Discussions in Mississippi, 2004 Mesoscale Discussions in Alabama, 2004 Mesoscale Discussions in Tennessee, 2004 Every mesoscale discussion in 2004

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.