Alert archive / Louisiana / Mesoscale Discussions in 2012
Mesoscale Discussion 218
The Storm Prediction Center issued this mesoscale discussion at Mar 2, 2012, 3:47 PM CST for 4 states. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Mar 2, 2012, 3:47 PM CST (21:47 UTC)
- Expired
- Mar 2, 2012, 4:45 PM CST
- In force
- 58 min
- Issued by
- the Storm Prediction Center
All 41 counties
Ashley County, AR, Chicot County, AR, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS, Jasper County, TX, Newton County, TX, Sabine County, TX, San Augustine County, TX, Tyler County, TX
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Shreveport, LA (KSHV), launched 12:00Z, 9.8 hours before the alert went out and 158 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
- 1427 J/kg
- Mixed-layer CIN
- -37 J/kg
- Mixed-layer LCL
- 626 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 347 m²/s²
- 0-3 km storm-relative helicity
- 292 m²/s²
- Significant tornado parameter
- 2.5
- Supercell composite
- 9.6
The text
As transmitted, in the capitals the NWS used until 2016.
703 ACUS11 KWNS 022147 SWOMCD SPC MCD 022147 MSZ000-LAZ000-ARZ000-TXZ000-022245- MESOSCALE DISCUSSION 0218 NWS STORM PREDICTION CENTER NORMAN OK 0347 PM CST FRI MAR 02 2012 AREAS AFFECTED...W-CNTRL MS...FAR SERN AR...NRN/CNTRL LA...E TX CONCERNING...SEVERE THUNDERSTORM WATCH 60... VALID 022147Z - 022245Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 60 CONTINUES. SFC ANALYSIS FROM 21Z SHOWS A DRYLINE SLOWLY PROGRESSING EWD ACROSS THE WW AREA. DISCRETE SUPERCELLS HAVE FORMED ACROSS NRN LA NEWD INTO ERN MS...WITH THE PRIMARY THREAT CONTINUING TO BE LARGE HAIL AND DMGG WINDS...WHILE FARTHER SWWD STORMS HAVE CONSOLIDATED INTO BROKEN LINE SEGMENTS. THE DOWNSTREAM ENVIRONMENT REMAINS MODERATELY UNSTABLE AND WILL CONTINUE TO SUPPORT TSTMS FARTHER E ACROSS THE WW AREA. LOCAL OFFICES MAY CONSIDER CLEARING COUNTIES FROM THE WW IN THE WAKE OF THE DRYLINE...AS MUCH DRIER AIR WILL LEAD TO REDUCED SVR POTENTIAL. ..ROGERS.. 03/02/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...JAN...LZK...LCH...SHV...HGX... LAT...LON 30519248 30519505 33409226 33378965 30519248
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 2, 10:28 AM CST | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Independence and 10 more | 62 min |
| Mar 2, 1:26 PM CST | Mesoscale Discussion | SPC | Ashley, Chicot | 64 min |
| Mar 2, 1:47 PM CST | Severe Thunderstorm Watch | SPC | Ashley, Chicot | 9 hr |
| Mar 2, 2:42 PM CST | Mesoscale Discussion | SPC | Ascension, East Baton Rouge, East Feliciana, Livingston, Saint Helena, Saint Tammany and 2 more | 63 min |
| Mar 2, 12:57 PM CST | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 32 more | 63 min |
| Mar 2, 1:20 PM CST | Tornado Watch | SPC | Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 24 more | 9 hr |
| Mar 2, 3:25 PM CST | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 24 more | 65 min |
| Mar 2, 4:37 PM CST | Tornado Watch | SPC | George, Greene, Perry, Stone, Wayne | 7 hr |
| Mar 2, 4:47 PM CST | Tornado Watch | SPC | Attala, Choctaw, Clarke, Clay, Copiah, Covington and 23 more | 6 hr |
Nearby
Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Texas, 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.