Alert archive / Mississippi / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 21
The Storm Prediction Center issued this severe thunderstorm watch at Feb 1, 2012, 3:45 PM CST for 4 states. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 1, 2012, 3:45 PM CST (21:45 UTC)
- Expired
- Feb 1, 2012, 6:35 PM CST
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 25 counties
Ashley County, AR, Chicot County, AR, Crittenden County, AR, Cross County, AR, Lee County, AR, Phillips County, AR, St. Francis County, AR, East Carroll Parish, LA, Morehouse Parish, LA, West Carroll Parish, LA, Bolivar County, MS, Coahoma County, MS, DeSoto County, MS, Humphreys County, MS, Issaquena County, MS, Leflore County, MS, Panola County, MS, Quitman County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Washington County, MS, Shelby County, TN
The radar
The Little Rock radar (KLZK), 145 km from the middle of the area, began a volume at 21:44 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 1, 3:55 PM CST | Severe Thunderstorm Warning | MEG | Lee, Phillips | 50 min |
| Feb 1, 4:25 PM CST | Tornado Warning | MEG | Phillips | 35 min |
| Feb 1, 4:31 PM CST | Severe Thunderstorm Warning | MEG | Phillips | 44 min |
| Feb 1, 4:33 PM CST | Severe Thunderstorm Warning | JAN | Bolivar, Sunflower | 57 min |
| Feb 1, 4:41 PM CST | Tornado Warning | MEG | Phillips | 49 min |
| Feb 1, 4:46 PM CST | Severe Thunderstorm Warning | MEG | Lee, Phillips | 44 min |
| Feb 1, 5:02 PM CST | Severe Thunderstorm Warning | MEG | Coahoma, Panola, Quitman, Tallahatchie | 43 min |
| Feb 1, 5:11 PM CST | Tornado Warning | JAN | Leflore, Sunflower | 49 min |
| Feb 1, 5:24 PM CST | Severe Thunderstorm Warning | JAN | Bolivar, Leflore, Sunflower, Washington | 43 min |
| Feb 1, 5:26 PM CST | Severe Thunderstorm Warning | MEG | Panola, Quitman, Tallahatchie | 34 min |
| Feb 1, 5:40 PM CST | Tornado Warning | MEG | Tallahatchie | 16 min |
| Feb 1, 5:44 PM CST | Severe Thunderstorm Warning | MEG | Lafayette, Panola, Tallahatchie, Yalobusha | 46 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Little Rock, AR (KLZK), launched 12:00Z, 9.8 hours before the alert went out and 104 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
- 34 J/kg
- Mixed-layer CIN
- -85 J/kg
- Mixed-layer LCL
- 838 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- -28 m²/s²
- 0-3 km storm-relative helicity
- 53 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
021
WWUS20 KWNS 012142
SEL1
SPC WW 012142
ARZ000-LAZ000-MSZ000-TNZ000-020300-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 21
NWS STORM PREDICTION CENTER NORMAN OK
345 PM CST WED FEB 1 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
EASTERN ARKANSAS
NORTHEAST LOUISIANA
NORTHWEST MISSISSIPPI
EXTREME SOUTHWEST TENNESSEE
EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 345 PM UNTIL
900 PM CST.
HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH
NORTHWEST OF MEMPHIS TENNESSEE TO 75 MILES SOUTH SOUTHWEST OF
GREENVILLE MISSISSIPPI. FOR A COMPLETE DEPICTION OF THE WATCH
SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
OTHER WATCH INFORMATION...CONTINUE...WW 20...
DISCUSSION...A CLUSTER OF STRONG/SEVERE THUNDERSTORMS OVER AR WILL
CONTINUE TO TRACK EASTWARD THIS AFTERNOON AND EARLY EVENING INTO
SOUTHWEST TN AND NORTHERN MS. STEEP LOW/MID LEVEL LAPSE RATES AND
STRONG WINDS ALOFT WILL PROMOTE A RISK OF HAIL AND GUSTY/DAMAGING
WINDS IN THE STRONGER CELLS AT LEAST THROUGH SUNSET.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 27035.
...HARTSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 1, 10:18 AM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 43 more | 117 min |
| Feb 1, 12:37 PM CST | Severe Thunderstorm Watch | SPC | Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 34 more | 5 hr |
| Feb 1, 1:22 PM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 35 more | 113 min |
| Feb 1, 2:58 PM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 25 more | 2 hr |
| Feb 1, 1:06 AM CST | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Calcasieu, Cameron, East Feliciana and 5 more | 114 min |
| Feb 1, 1:36 PM CST | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 12 more | 84 min |
| Feb 1, 5:18 PM CST | Mesoscale Discussion | SPC | Ascension, Livingston, Orleans, Saint Charles, Saint James, Saint John the Baptist and 2 more | 87 min |
| Feb 1, 4:49 PM CST | Mesoscale Discussion | SPC | Attala, Benton, Calhoun, Carroll, Chickasaw, Choctaw and 17 more | 56 min |
| Feb 1, 4:59 PM CST | Severe Thunderstorm Watch | SPC | Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 21 more | 4 hr |
Nearby
Severe Thunderstorm Watches in Mississippi, 2012Severe Thunderstorm Watches in Arkansas, 2012Severe Thunderstorm Watches in Louisiana, 2012Every severe thunderstorm watch 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.