Alert archive / Arkansas / Mesoscale Discussions in 2012
Mesoscale Discussion 749
The Storm Prediction Center issued this mesoscale discussion at May 7, 2012, 4:38 PM CDT for 11 counties in Arkansas; 6 parishes in Louisiana; 10 counties in Texas. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- May 7, 2012, 4:38 PM CDT (21:38 UTC)
- Expired
- May 7, 2012, 5:45 PM CDT
- In force
- 67 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 27 counties
Clark County, AR, Columbia County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Sevier County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, Red River Parish, LA, Webster Parish, LA, Bowie County, TX, Camp County, TX, Cass County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Titus County, TX, Upshur County, TX
The radar
The Shreveport radar (KSHV), 81 km from the middle of the area, began a volume at 21:39 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
Shreveport, LA (KSHV), launched 12:00Z, 9.6 hours before the alert went out and 80 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
- 746 J/kg
- Mixed-layer CIN
- -132 J/kg
- Mixed-layer LCL
- 1458 m above ground
- 0-6 km bulk shear
- 5 kt
- 0-1 km storm-relative helicity
- -54 m²/s²
- 0-3 km storm-relative helicity
- -19 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
150
ACUS11 KWNS 072138
SWOMCD
SPC MCD 072138
LAZ000-ARZ000-TXZ000-OKZ000-072245-
MESOSCALE DISCUSSION 0749
NWS STORM PREDICTION CENTER NORMAN OK
0438 PM CDT MON MAY 07 2012
AREAS AFFECTED...TEXARKANA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 072138Z - 072245Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...A CLUSTER OF STORMS IS DEVELOPING OVER W CNTRL AR...WITH
ADDITIONAL DEVELOPMENT POSSIBLE INTO N CNTRL LA AND NERN TX. THESE
STORMS MAY GRADUALLY DRIFT SEWD WITH TIME. AREA IS BEING MONITORED
FOR A POSSIBLE WW.
DISCUSSION...CONVECTION IS BEGINNING TO INCREASE ALONG THE
INTERSECTION OF A REMNANT OUTFLOW BOUNDARY /EVIDENT ON 21Z VISIBLE
IMAGERY FROM NERN LA NWWD INTO W CNTRL AR/ AND A COLD FRONT
EXTENDING FROM CNTRL TX NEWD TO ERN IND. A SUBTLE AREA OF IMPLIED
FORCING FOR ASCENT IS NOTED ON WV IMAGERY OVER WRN AR/LA...AND
APPEARS TO BE ASSOCIATED WITH YESTERDAY/S SEVERE CONVECTION IN CNTRL
TX. AS SUCH...STORMS MAY BEGIN TO INCREASE IN COVERAGE AMIDST A
MOIST AND MODERATELY UNSTABLE AIR MASS. WINDS OF ABOUT 20-25 KT
ABOVE 2 KFT PER VAD WIND PROFILE AND PROFILER DATA MAY SUPPORT
WEAKLY ORGANIZED CLUSTERS OF STORMS...PRIMARILY CAPABLE OF DMGG
WINDS AND HAIL.
..HURLBUT/THOMPSON.. 05/07/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LZK...SHV...FWD...
LAT...LON 33049540 33859484 34569397 34299335 33549279 32939258
32029291 32139393 32329475 33049540SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 7, 5:21 PM CDT | Severe Thunderstorm Watch | SPC | Calhoun, Clark, Columbia, Dallas, Hempstead, Howard and 8 more | 5 hr |
| May 7, 1:07 PM CDT | Severe Thunderstorm Watch | SPC | Catahoula, Concordia, Franklin, Madison, Richland, Tensas | 5 hr |
| May 7, 3:53 PM CDT | Mesoscale Discussion | SPC | Catahoula, Concordia, Franklin, Madison, Tensas | 97 min |
| May 7, 12:46 PM CDT | Severe Thunderstorm Watch | SPC | Brewster, Brown, Callahan, Coke, Coleman, Concho and 23 more | 8 hr |
| May 7, 2:24 PM CDT | Mesoscale Discussion | SPC | Andrews, Crane, Ector, Gaines, Loving, Midland and 3 more | 2 hr |
| May 7, 2:37 PM CDT | Mesoscale Discussion | SPC | Bandera, Blanco, Burnet, Concho, Gillespie, Kendall and 11 more | 83 min |
| May 7, 3:27 PM CDT | Severe Thunderstorm Watch | SPC | Bandera, Bastrop, Bell, Bexar, Blanco, Bosque and 30 more | 7 hr |
| May 7, 3:56 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Culberson, Ector, Gaines, Jeff Davis, Loving and 4 more | 7 hr |
| May 7, 5:31 PM CDT | Mesoscale Discussion | SPC | Bandera, Bastrop, Bell, Blanco, Burnet, Comal and 28 more | 89 min |
| May 7, 6:55 PM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Crane, Dawson, Ector, Gaines and 11 more | 95 min |
Nearby
Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Louisiana, 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.