Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 2186
The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2012, 4:08 AM CST for 5 states. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- Dec 20, 2012, 4:08 AM CST (10:08 UTC)
- Expired
- Dec 20, 2012, 5:15 AM CST
- In force
- 67 min
- Issued by
- the Storm Prediction Center
All 120 counties
Choctaw County, AL, Colbert County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Lamar County, AL, Lauderdale County, AL, Marion County, AL, Pickens County, AL, Sumter County, AL, Washington County, AL, Chicot County, AR, Crittenden County, AR, Avoyelles Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Iberville Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Richland Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Alcorn County, MS, Amite County, MS, Attala County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Clay County, MS, Coahoma County, MS, Copiah County, MS, Covington County, MS, DeSoto County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lafayette County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wayne County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS, Fayette County, TN, Hardeman County, TN, McNairy County, TN, Shelby County, TN
The radar
The Jackson/Brandon,MS radar (KDGX), 44 km from the middle of the area, began a volume at 10:07 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.
The nearest sounding before it
Jackson, MS (KJAN), launched 00:00Z, 10.1 hours before the alert went out and 36 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1606 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 206 m²/s²
- 0-3 km storm-relative helicity
- 246 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
440
ACUS11 KWNS 201008
SWOMCD
SPC MCD 201008
ALZ000-TNZ000-MSZ000-LAZ000-ARZ000-201115-
MESOSCALE DISCUSSION 2186
NWS STORM PREDICTION CENTER NORMAN OK
0408 AM CST THU DEC 20 2012
AREAS AFFECTED...ERN AR/WRN TN/LA/MS/WRN AL
CONCERNING...SEVERE THUNDERSTORM WATCH 688...
VALID 201008Z - 201115Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 688
CONTINUES.
SUMMARY...A THREAT FOR DAMAGING WINDS AND A TORNADO OR TWO PERSISTS
ACROSS WW 688...WITH RECENT TRENDS IN STORM INTENSITY/LIGHTNING DATA
SUGGESTING THESE THREATS TO BE GREATEST ACROSS AR/TN/NWRN MS
PORTIONS OF THIS SVR TSTM WATCH.
MEANWHILE...NEW CONVECTION/TSTMS WILL CONTINUE TO DEVELOP OVER SERN
LA AND SRN MS...WITH THIS ACTIVITY TRACKING ENEWD INTO CENTRAL/SRN
AL. THIS WARM SECTOR ACTIVITY MAY WARRANT A SEPARATE WW.
DISCUSSION...TRENDS IN REGIONAL RADAR IMAGERY/LIGHTNING DATA SHOWED
SUSTAINED TSTMS/QLCS PROGRESSING EWD INTO NWRN MS...AND APPROACHING
FAR WRN TN. DESPITE WEAKER INSTABILITY IN THESE AREAS /MUCAPE
200-400 J PER KG/...STRONGER FORCING FOR ASCENT/DPVA ATTENDANT TO
THE STRONG SHORTWAVE TROUGH MOVING TOWARD THE MID MS/LOWER OH/TN
VALLEYS WILL MAINTAIN QLCS WITH EWD EXTENT. WFO/S MAY NEED TO
EXTEND THE NRN PART OF WW 688 EWD TO INCLUDE MORE OF SWRN TN AND NRN
MS EARLY THIS MORNING.
THE SRN EXTENT OF THE QLCS HAS BECOME LESS INTENSE /I.E. LACK OF CG
LIGHTNING/ ACROSS NERN TO SWRN LA. THIS IS LIKELY DUE TO A MIDLEVEL
WARM LAYER NOTED ON THE 06Z SLIDELL SPECIAL SOUNDING. ALTHOUGH THIS
LINE HAS WEAKENED...GREATER CONCERN EXISTS IN THE PRE-FRONTAL WARM
SECTOR ACROSS SERN LA TO SRN MS WHERE RICH MOISTURE EXISTS WITH
SURFACE DEWPOINTS AROUND 70 F. RADAR IMAGERY SHOWED SOME LOW LEVEL
ROTATION WITH THE CONVECTION/TSTMS TO THE SSW-NNE OF KBTR. THUS...A
TORNADO THREAT MAY BE DEVELOPING WITH THIS PRE-FRONTAL ACTIVITY AS
IT PROGRESSES ENEWD ACROSS SRN MS TO CENTRAL/SRN PARTS OF AL THIS
MORNING. VWP DATA AT SLIDELL HAS SHOWED 40-45 KT 850 MB FLOW BEING
MAINTAINED WITH LOW LEVEL SPEED SHEAR AND HODOGRAPH CURVATURE /0-1
KM SRH AROUND 200 M2 PER S2/.
..PETERS/EDWARDS.. 12/20/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...OHX...BMX...HUN...MOB...MEG...JAN...LIX...LZK...
LCH...SHV...
LAT...LON 30899297 32469200 33499115 34859055 35469039 35438881
34958751 32998767 31438793 30658887 30369048 30209152
30899297SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 20, 4:23 AM CST | Tornado Watch | SPC | Autauga, Baldwin, Barbour, Bibb, Bullock, Butler and 34 more | 9 hr |
| Dec 20, 7:09 AM CST | Mesoscale Discussion | SPC | Autauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 22 more | 96 min |
| Dec 20, 8:49 AM CST | Mesoscale Discussion | SPC | Dale, Geneva, Henry, Houston | 56 min |
| Dec 20, 9:19 AM CST | Tornado Watch | SPC | Coffee, Dale, Geneva, Henry, Houston | 9 hr |
| Dec 20, 9:56 AM CST | Mesoscale Discussion | SPC | Autauga, Baldwin, Bibb, Butler, Chambers, Chilton and 22 more | 64 min |
| Dec 20, 1:31 PM CST | Mesoscale Discussion | SPC | Barbour, Coffee, Dale, Geneva, Henry, Houston and 1 more | 59 min |
| Dec 19, 7:07 PM CST | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Conway, Crawford and 24 more | 53 min |
| Dec 19, 7:36 PM CST | Tornado Watch | SPC | Baxter, Benton, Boone, Carroll, Clark, Cleburne and 36 more | 6 hr |
| Dec 19, 10:22 PM CST | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Clark, Cleburne, Conway and 29 more | 83 min |
| Dec 19, 11:55 PM CST | Mesoscale Discussion | SPC | Ashley, Chicot | 95 min |
| Dec 20, 12:50 AM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 23 more | 55 min |
| Dec 20, 1:07 AM CST | Severe Thunderstorm Watch | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 18 more | 5 hr |
| Dec 19, 9:56 PM CST | Severe Thunderstorm Watch | SPC | Bossier, Caddo, De Soto | 5 hr |
Nearby
Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Alabama, 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.