Alert archive / Alabama / Mesoscale Discussions in 2003

Mesoscale Discussion 79

February 15, 200327 counties in Alabama; Lowndes County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 15, 2003, 5:18 PM CST for 27 counties in Alabama; Lowndes County, Mississippi. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Feb 15, 2003, 5:18 PM CST (23:18 UTC)
Expired: Feb 15, 2003, 7:15 PM CST
In force: 117 min
Issued by: the Storm Prediction Center

All 28 counties

Bibb County, AL, Blount County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Cullman County, AL, Dallas County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lawrence County, AL, Marengo County, AL, Marion County, AL, Monroe County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Winston County, AL, Lowndes County, MS

The radar

The Birmingham radar (KBMX), 60 km from the middle of the area, began a volume at 23:19 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 8Feb 15, 5:40 PM CST

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 11.3 hours before the alert went out and 59 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: 451 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: -81 m²/s²
0-3 km storm-relative helicity: -30 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.

322 
ACUS11 KWNS 152319
SWOMCD
SPC MCD 152318 
MSZ000-ALZ000-160115-

MESOSCALE DISCUSSION 0079
NWS STORM PREDICTION CENTER NORMAN OK
0518 PM CST SAT FEB 15 2003

AREAS AFFECTED...WRN HALF OF AL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 152318Z - 160115Z

THUNDERSTORMS MOVING ENEWD ACROSS MS ARE EXPECTED TO MOVE OUT OF
WW AROUND 16/0030Z.  WE ARE MONITORING THE CONVECTIVE EVOLUTION
FOR THE POTENTIAL FOR A NEW WW ACROSS PARTS OF WRN AL.



MESOLOW APPARENT IN RADAR REFLECTIVITY OVER CENTRAL MS CONTINUES
MOVING ENEWD...WITH BROKEN LINE OF STORMS INCLUDING BOWING
SEGMENTS OBSERVED SOUTH OF THIS FEATURE.  ALTHOUGH A FEW OF THE
STORMS WITHIN THE LINE CONTINUE TO SHOW WEAK ROTATION...AN
OVERALL WEAKENING TREND IS APPARENT IN RADAR REFLECTIVITY LOOP
OVER THE PAST HALF HOUR. 



NONETHELESS...MOIST / MARGINALLY UNSTABLE AIRMASS IS OBSERVED
EAST OF CURRENT WW ACROSS AL...AND DEEP-LAYER WIND SHEAR REMAINS
FAVORABLE FOR SEVERE STORMS / SUPERCELLS.  ALTHOUGH INSTABILITY
SHOULD WEAKEN FURTHER WITH THE LOSS OF DAYTIME HEATING...MOIST /
KINEMATICALLY FAVORABLE ENVIRONMENT SUGGESTS THAT A LIMITED
SEVERE THREAT MAY CONTINUE AS MESOLOW AND ASSOCIATED CONVECTION
MOVES EAST OF CURRENT WW.  

..GOSS.. 02/15/2003

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

34578758 34628693 34408645 33638625 32498672 31298747
31288862 34038842

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 15, 5:40 PM CST	Tornado Watch	SPC	Autauga, Bibb, Blount, Butler, Chilton, Choctaw and 19 more	4 hr
Feb 15, 1:48 PM CST	Mesoscale Discussion	SPC	Amite, Covington, Forrest, Jasper, Jefferson Davis, Jones and 11 more	117 min
Feb 15, 3:05 PM CST	Tornado Watch	SPC	Attala, Carroll, Choctaw, Clarke, Covington, Forrest and 27 more	6 hr
Feb 15, 5:51 PM CST	Mesoscale Discussion	SPC	Attala, Carroll, Choctaw, Clarke, Covington, Forrest and 27 more	114 min

Nearby

Mesoscale Discussions in Alabama, 2003 Mesoscale Discussions in Mississippi, 2003 Every mesoscale discussion in 2003

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.