Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 35
The Storm Prediction Center issued this mesoscale discussion at Jan 20, 2012, 10:02 PM CST for 4 states. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Jan 20, 2012, 10:02 PM CST (04:02 UTC)
- Expired
- Jan 20, 2012, 11:30 PM CST
- In force
- 88 min
- Issued by
- the Storm Prediction Center
All 44 counties
Colbert County, AL, Lauderdale County, AL, Limestone County, AL, Lee County, AR, Phillips County, AR, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Coahoma County, MS, DeSoto County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Yalobusha County, MS, Chester County, TN, Decatur County, TN, Fayette County, TN, Giles County, TN, Hardeman County, TN, Hardin County, TN, Henderson County, TN, Hickman County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Madison County, TN, Marshall County, TN, Maury County, TN, McNairy County, TN, Moore County, TN, Perry County, TN, Shelby County, TN, Wayne County, TN
The radar
The Columbus AFB radar (KGWX), 99 km from the middle of the area, began a volume at 04:05 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
Little Rock, AR (KLZK), launched 00:00Z, 4.0 hours before the alert went out and 119 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
- 668 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 405 m²/s²
- 0-3 km storm-relative helicity
- 505 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
775
ACUS11 KWNS 210402
SWOMCD
SPC MCD 210402
TNZ000-ALZ000-MSZ000-ARZ000-210530-
MESOSCALE DISCUSSION 0035
NWS STORM PREDICTION CENTER NORMAN OK
1002 PM CST FRI JAN 20 2012
AREAS AFFECTED...ERN AR...NRN MS...SRN TN...NW AL
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 210402Z - 210530Z
A SEVERE THREAT IS EXPECTED TO DEVELOP ACROSS ERN AR...NRN MS...SRN
TN AND NW AL LATE THIS EVENING OR EARLY DURING THE OVERNIGHT PERIOD.
AN ISOLATED THREAT FOR TORNADOES AND WIND DAMAGE MAY EXIST AS STORMS
INCREASE IN COVERAGE OVER THE NEXT 2 TO 4 HOURS. WW ISSUANCE MAY
BECOME NECESSARY ACROSS THE REGION.
THE LATEST SFC ANALYSIS SHOWS A 1007 MB LOW NEAR TEXARKANA WITH A
STATIONARY FRONT EXTENDING ENEWD FROM THE LOW ACROSS ERN AR INTO
SWRN TN AND NRN AL. THUNDERSTORMS ARE DEVELOPING IN NW TN ON THE NRN
SIDE OF THE FRONTAL BOUNDARY AHEAD OF A VORTICITY MAX AND SHORTWAVE
TROUGH LOCATED IN CNTRL MO. AS THIS FEATURE MOVES EWD...LARGE-SCALE
ASCENT WILL INCREASE IN THE TN VALLEY HELPING TO INITIATE STORMS
ALONG THE FRONT. THIS ACTIVITY SHOULD INCREASE QUICKLY IN THE 06Z TO
09Z TIMEFRAME WITH STORMS LIKELY MOVING ENEWD ACROSS THE MCD AREA.
MESOSCALE ANALYSIS ALONG AND JUST SOUTH OF THE BOUNDARY SUGGEST
MLCAPE VALUES ARE IN THE 500 TO 1000 J/KG RANGE. THIS COMBINED WITH
THE LACK OF A STRONG INVERSION LAYER SOUTH OF THE BOUNDARY SHOULD
ALLOW FOR SFC-BASED THUNDERSTORM DEVELOPMENT. FORECAST SOUNDINGS
TONIGHT SOUTH OF MEMPHIS AND NEAR TUPELO SHOW 45 TO 55 KT OF DEEP
LAYER SHEAR ALONG WITH UNIDIRECTIONAL WIND PROFILES. THIS WOULD
FAVOR A WIND DAMAGE THREAT IF CELLS CAN ORGANIZE INTO A LINE. IF THE
CELLS TEND TO REMAIN DISCRETE AND ROTATE...THEN THE STRONG SPEED
SHEAR IN THE BOUNDARY LAYER MAY ALLOW AN ISOLATED TORNADO THREAT TO
DEVELOP.
..BROYLES.. 01/21/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...OHX...HUN...MEG...JAN...LZK...
LAT...LON 34428793 34638718 34958641 35218629 35478641 35688678
35818739 35708875 35119042 34759090 34329109 34009105
33729076 33739001 33998906 34428793SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 20, 10:35 PM CST | Tornado Watch | SPC | Colbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 6 more | 8 hr |
| Jan 21, 1:52 AM CST | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 31 more | 113 min |
| Jan 21, 4:20 AM CST | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 35 more | 55 min |
| Jan 21, 4:55 AM CST | Tornado Watch | SPC | Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 37 more | 7 hr |
| Jan 21, 7:22 AM CST | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Bullock, Calhoun, Chambers and 32 more | 83 min |
| Jan 21, 10:01 AM CST | Mesoscale Discussion | SPC | Autauga, Barbour, Bibb, Bullock, Butler, Chambers and 25 more | 59 min |
| Jan 21, 11:28 AM CST | Tornado Watch | SPC | Barbour, Bullock, Chambers, Clay, Henry, Lee and 4 more | 8 hr |
| Jan 21, 1:57 PM CST | Mesoscale Discussion | SPC | Barbour, Bullock, Chambers, Clay, Henry, Lee and 4 more | 63 min |
| Jan 21, 4:48 PM CST | Mesoscale Discussion | SPC | Henry | 57 min |
Nearby
Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Tennessee, 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.