Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 1865
The Storm Prediction Center issued this mesoscale discussion at Sep 2, 2012, 7:13 PM CDT for 4 states. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- Sep 2, 2012, 7:13 PM CDT (00:13 UTC)
- Expired
- Sep 2, 2012, 8:15 PM CDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
All 50 counties
Colbert County, AL, Fayette County, AL, Franklin County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Marion County, AL, Walker County, AL, Winston County, AL, Crittenden County, AR, Alcorn County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Clay County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Webster County, MS, Yalobusha County, MS, Fayette County, TN, Giles County, TN, Hardeman County, TN, Hardin County, TN, Lawrence County, TN, McNairy County, TN, Shelby County, TN, Wayne County, TN
The radar
The Columbus AFB radar (KGWX), 104 km from the middle of the area, began a volume at 00:14 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 nearest sounding before it
Little Rock, AR (KLZK), launched 00:00Z, 0.2 hours before the alert went out and 88 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
- 2460 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 1418 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 80 m²/s²
- 0-3 km storm-relative helicity
- 169 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.2
The text
As transmitted, in the capitals the NWS used until 2016.
829 ACUS11 KWNS 030014 SWOMCD SPC MCD 030013 ALZ000-TNZ000-MSZ000-ARZ000-030115- MESOSCALE DISCUSSION 1865 NWS STORM PREDICTION CENTER NORMAN OK 0713 PM CDT SUN SEP 02 2012 AREAS AFFECTED...NRN MS...NWRN AL...FAR ERN AR...FAR SWRN TN CONCERNING...TORNADO WATCH 609... VALID 030013Z - 030115Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 609 CONTINUES. SUMMARY...TSTM ACTIVITY ACROSS THE WATCH AREA IS EXPECTED TO INCREASE DURING THE NEXT HOUR OR TWO. AT LEAST A MODEST THREAT FOR A BRIEF TORNADO AS WELL AS A FEW DAMAGING WIND GUSTS IS EXPECTED WITH THIS ACTIVITY. DISCUSSION...LATEST RADAR TRENDS SHOW INCREASING TSTM COVERAGE ACROSS NRN MS AND SWRN TN IN AN AREA OF ENHANCED SURFACE CONVERGENCE. TEMPERATURES REMAIN IN THE UPPER 80S AND LOW 90S WITH DEWPOINTS IN THE LOW 70S...SUPPORTING MLCAPE NEAR 2000 J/KG. THE LOW-LEVEL SHEAR HAS REMAINED LARGELY UNCHANGED DURING THE PAST FEW HOURS WITH THE LATEST MESOANALYSIS DEPICTING EFFECTIVE SRH NEAR 100 M2/S2. SFC WINDS ACROSS THE SERN PORTIONS OF THE WATCH AREA ARE STILL MOSTLY SLY...RESULTING IN SLIGHTLY INCREASED LOW-LEVEL SHEAR. VAD WIND PROFILE FROM GWX CORRELATES THIS WELL WITH 0-1 KM SRH BETWEEN 150 AND 200 J/KG. GIVEN THESE CONDITIONS...THE THREAT FOR DAMAGING WINDS AS WELL AS BRIEF TORNADOES IS EXPECTED TO PERSIST FOR AT LEAST THE NEXT FEW HOURS. THE ACTIVITY ACROSS NWRN MS MAY BEGIN TO ORGANIZE INTO A FORWARD-PROPAGATING MCS WITH AN ENHANCED POTENTIAL FOR STRONG/SEVERE WIND GUSTS. HOWEVER...CURRENT RADAR TRENDS STILL SHOW MORE OF MULTICELL CLUSTER...SUGGESTING UPSCALE GROWTH/ORGANIZATION INTO A LINEAR MCS MAY BE SLOW TO OCCUR. ..MOSIER.. 09/03/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...OHX...BMX...HUN...MEG...JAN...LZK... LAT...LON 33379098 35419069 35428698 33368736 33379098
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 2, 8:43 PM CDT | Mesoscale Discussion | SPC | Calhoun, Cherokee, Cleburne, DeKalb, Etowah, St. Clair | 62 min |
| Sep 2, 9:48 PM CDT | Mesoscale Discussion | SPC | Fayette, Lamar, Marion, Walker, Winston | 57 min |
| Sep 3, 12:29 PM CDT | Mesoscale Discussion | SPC | Barbour, Bullock, Butler, Clarke, Coffee, Conecuh and 11 more | 61 min |
| Sep 3, 3:25 PM CDT | Mesoscale Discussion | SPC | Autauga, Barbour, Bibb, Bullock, Butler, Chilton and 16 more | 65 min |
| Sep 3, 3:46 PM CDT | Tornado Watch | SPC | Autauga, Bibb, Butler, Chilton, Choctaw, Clarke and 19 more | 7 hr |
| Sep 3, 6:55 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Butler, Chilton, Choctaw, Clarke and 19 more | 65 min |
Nearby
Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Tennessee, 2012Every mesoscale discussion in 2012
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.