Alert archive / Mississippi / Mesoscale Discussions in 2003
Mesoscale Discussion 1939
The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2003, 1:10 PM CDT for 15 counties in Alabama; 18 counties in Mississippi. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Jul 21, 2003, 1:10 PM CDT (18:10 UTC)
- Expired
- Jul 21, 2003, 2:45 PM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
All 33 counties
Blount County, AL, Colbert County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Franklin County, AL, Jackson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Winston County, AL, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Monroe County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Yalobusha County, MS
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Little Rock, AR (KLZK), launched 12:00Z, 6.2 hours before the alert went out and 153 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.
- Mixed-layer CAPE
- 1960 J/kg
- Mixed-layer CIN
- -171 J/kg
- Mixed-layer LCL
- 1593 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 53 m²/s²
- 0-3 km storm-relative helicity
- 81 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
265 ACUS11 KWNS 211810 SWOMCD SPC MCD 211810 ALZ000-MSZ000-211945- MESOSCALE DISCUSSION 1939 NWS STORM PREDICTION CENTER NORMAN OK 0110 PM CDT MON JUL 21 2003 AREAS AFFECTED...NRN MS...NRN AL CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 211810Z - 211945Z LINE OF SEVERE STORMS FROM MIDDLE TN SWWD INTO SWRN TN IS EXPECTED TO CONTINUE MOVING SEWD 25 KT TOWARD NERN MS/NWRN AL. A NEW WATCH WILL BE ISSUED ACROSS NRN MS/NRN AL WITHIN THE NEXT HOUR. AIR MASS ACROSS THIS REGION IS VERY MOIST/EXTREMELY UNSTABLE WITH SURFACE DEW POINTS IN MID/UPPER 70S AND SBCAPE GREATER THAN 4000 J/KG. WATER VAPOR IMAGERY SHOWS LEADING EDGE OF MID/UPPER DRYING MOVING SEWD INTO THE LOWER TN VALLEY SUGGESTING SRN END OF SHORT WAVE TROUGH IS INFLUENCING THIS CONVECTIVE ACTIVITY. STORMS ARE EXPECTED TO INTENSIFY ALONG WRN PORTION OF THE THUNDERSTORM LINE OVER THE NEXT SEVERAL HOURS...WITH THE LINE EXPECTED TO MOVE INTO NRN MS/NRN AL THIS AFTERNOON. ..WEISS.. 07/21/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BMX...HUN...MEG...JAN... 33778864 33898978 34189050 34669016 34918923 35008713 34968570 33878570
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 1:45 PM CDT | Severe Thunderstorm Watch | SPC | Blount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 13 more | 5 hr |
| Jul 21, 3:14 PM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Clay, Cleburne, Colbert and 23 more | 2 hr |
| Jul 21, 6:00 PM CDT | Severe Thunderstorm Watch | SPC | Autauga, Bibb, Calhoun, Chambers, Chilton, Choctaw and 18 more | 5 hr |
Nearby
Mesoscale Discussions in Mississippi, 2003Mesoscale Discussions in Alabama, 2003Every 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.