Alert archive / Texas / Mesoscale Discussions in 2011
Mesoscale Discussion 433
The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2011, 11:56 PM CDT for 4 parishes in Louisiana; 22 counties in Texas. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Apr 14, 2011, 11:56 PM CDT (04:56 UTC)
- Expired
- Apr 15, 2011, 1:30 AM CDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
All 26 counties
Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Webster Parish, LA, Anderson County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Ellis County, TX, Freestone County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Hill County, TX, Kaufman County, TX, Limestone County, TX, Marion County, TX, Navarro County, TX, Panola County, TX, Rains County, TX, Rockwall County, TX, Rusk County, TX, Smith County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Shreveport radar (KSHV), 92 km from the middle of the area, began a volume at 05:00 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 00:00Z, 4.9 hours before the alert went out and 101 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
- 1201 J/kg
- Mixed-layer CIN
- -8 J/kg
- Mixed-layer LCL
- 1314 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 117 m²/s²
- 0-3 km storm-relative helicity
- 135 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 6.5
The text
As transmitted, in the capitals the NWS used until 2016.
560
ACUS11 KWNS 150456
SWOMCD
SPC MCD 150456
LAZ000-ARZ000-TXZ000-150630-
MESOSCALE DISCUSSION 0433
NWS STORM PREDICTION CENTER NORMAN OK
1156 PM CDT THU APR 14 2011
AREAS AFFECTED...N-CNTRL/NERN TX AND NWRN LA
CONCERNING...SEVERE THUNDERSTORM WATCH 137...138...
VALID 150456Z - 150630Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
137...138...CONTINUES.
CONVECTION WILL CONTINUE BUILDING SWD ACROSS N-CNTRL TX IN RESPONSE
TO STRONG LOW-LEVEL CONVERGENCE ALONG A COLD FRONT OVERTAKING A
DRYLINE. THE COMBINATION OF MLCAPE VALUES OF 1000-2000 J/KG AND
EFFECTIVE BULK SHEAR MAGNITUDES AOA 50 KT IMMEDIATELY AHEAD OF THE
FRONT WILL PROMOTE ORGANIZED LINEAR CONVECTIVE STRUCTURES WITH AN
ATTENDANT THREAT FOR DMGG WINDS AND LARGE HAIL. WHILE EFFECTIVE SRH
VALUES AOA 300 M2/S2 COULD SUPPORT A BRIEF TORNADO THREAT...THE
UNDERCUTTING NATURE OF THE SYNOPTIC BOUNDARY AND ANTICIPATED LINEAR
CONVECTIVE MODE WILL BE ASSOCIATED WITH DMGG STRAIGHT-LINE WINDS AS
THE PRIMARY THREAT. LARGE HAIL WILL ALSO BE A CONCERN WITH STEEP
MID-LEVEL LAPSE RATES AROUND 8 C/KM IMPINGING ON THE DEVELOPING
CONVECTION. STRONG WLY CLOUD-BEARING FLOW WILL ALLOW STORMS TO
SPREAD INTO NERN TX AND EVENTUALLY NWRN LA DURING THE OVERNIGHT
HOURS...AND THUS SVR TSTM WATCH 138 HAS BEEN ISSUED DOWNSTREAM OF WW
137.
..COHEN.. 04/15/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...SHV...FWD...
LAT...LON 31879396 31729450 31639528 31399631 31629717 32169728
33009642 33049571 33019477 33109433 33159389 33099339
32749325 32459333 32209352 31879396SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 14, 11:24 PM CDT | Severe Thunderstorm Watch | SPC | Bossier, Caddo, Claiborne, De Soto, Webster | 3 hr |
| Apr 15, 1:27 AM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Claiborne, East Carroll, Jackson, Lincoln and 5 more | 93 min |
| Apr 15, 2:19 AM CDT | Tornado Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more | 8 hr |
| Apr 15, 4:21 AM CDT | Mesoscale Discussion | SPC | Caldwell, Catahoula, Concordia, East Carroll, Franklin, Grant and 6 more | 84 min |
| Apr 15, 7:32 AM CDT | Tornado Watch | SPC | Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, Franklin and 8 more | 7 hr |
| Apr 15, 10:28 AM CDT | Mesoscale Discussion | SPC | Caldwell, Catahoula, Concordia, East Carroll, Franklin, LaSalle and 4 more | 2 hr |
| Apr 15, 1:30 PM CDT | Mesoscale Discussion | SPC | Avoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana, Pointe Coupee and 6 more | 2 hr |
| Apr 15, 2:41 PM CDT | Tornado Watch | SPC | Acadia, Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge and 19 more | 7 hr |
| Apr 15, 3:35 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Avoyelles, Concordia, East Baton Rouge, East Feliciana and 15 more | 85 min |
| Apr 15, 6:09 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 12 more | 96 min |
| Apr 14, 8:36 PM CDT | Mesoscale Discussion | SPC | Lamar | 84 min |
| Apr 14, 9:06 PM CDT | Tornado Watch | SPC | Bowie, Cooke, Delta, Fannin, Franklin, Grayson and 4 more | 6 hr |
| Apr 14, 9:59 PM CDT | Mesoscale Discussion | SPC | Collin, Dallas, Denton, Hopkins, Hunt, Rockwall | 31 min |
| Apr 14, 10:04 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Collin, Coryell, Dallas, Denton and 19 more | 4 hr |
| Apr 14, 11:11 PM CDT | Mesoscale Discussion | SPC | Bowie, Delta, Fannin, Lamar, Red River, Titus | 94 min |
Nearby
Mesoscale Discussions in Texas, 2011Mesoscale Discussions in Louisiana, 2011Every mesoscale discussion in 2011
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.