Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 2049

August 24, 20116 parishes in Louisiana; 18 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2011, 3:50 PM CDT for 6 parishes in Louisiana; 18 counties in Texas. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Aug 24, 2011, 3:50 PM CDT (20:50 UTC)
Expired
Aug 24, 2011, 5:15 PM CDT
In force
85 min
Issued by
the Storm Prediction Center
All 24 counties

Grant Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Angelina County, TX, Camp County, TX, Cherokee County, TX, Delta County, TX, Franklin County, TX, Gregg County, TX, Hopkins County, TX, Nacogdoches County, TX, Panola County, TX, Rains County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 44 km from the middle of the area, began a volume at 20:53 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 nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 8.8 hours before the alert went out and 53 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.

Skew-T log-pSkew-T log-p diagram, Shreveport, LA at 12:00Z on 2011-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1956 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2011-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1956 J/kg
Mixed-layer CIN
-126 J/kg
Mixed-layer LCL
1219 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

927 
ACUS11 KWNS 242051
SWOMCD
SPC MCD 242050
LAZ000-TXZ000-242215-

MESOSCALE DISCUSSION 2049
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT WED AUG 24 2011

AREAS AFFECTED...E TX/CENTRAL LA

CONCERNING...SEVERE THUNDERSTORM WATCH 801...

VALID 242050Z - 242215Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 801
CONTINUES.

WIDESPREAD STORMS AND ISOLATED SEVERE POTENTIAL CONTINUES.

LATEST RADAR IMAGERY SHOWS AN ARCING BAND OF STORMS CONTINUING A
SWWD PROGRESSION ACROSS E TX AND THE CENTRAL THIRD OF LA ATTM...WITH
NEW STORMS INCREASING ACROSS NERN TX.  AIRMASS REMAINS FAVORABLY
UNSTABLE ACROSS THIS REGION...BUT DECREASES WITH WWD EXTENT INTO N
TX.

HOWEVER...A WELL-DEFINED GUST FRONT EXTENDS FROM W OF KPRX /PARIS
TX/ IN A SW/EWD ARC TO NEAR KPOE /FT. POLK LA/...WHICH SHOULD
CONTINUE TO FUEL ANAFRONTAL-TYPE DEVELOPMENT OF ADDITIONAL
CONVECTION.  WITH FAIRLY DEEP MIXED LAYER /SURFACE DEWPOINT
DEPRESSIONS OF 30 TO 40 F/...EVAPORATIVELY-ASSISTED WIND GUSTS NEAR
SEVERE LEVELS REMAIN POSSIBLE IN LOCAL AREAS.  THOUGH THE THREAT
CONTINUES TO SPREAD ACROSS/OUT OF WW 801...NEW WW IS NOT ANTICIPATED
ATTM GIVEN VERY ISOLATED NATURE OF THREAT.

..GOSS.. 08/24/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...JAN...LCH...SHV...HGX...FWD...

LAT...LON   33389521 32609476 32069401 31709272 31769213 31179184
            30959386 31489532 32779596 33489567 33389521

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 24, 12:06 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 12 more114 min
Aug 24, 1:17 PM CDTSevere Thunderstorm WatchSPCBienville, Bossier, Caddo, Caldwell, De Soto, Grant and 6 more4 hr
Aug 24, 4:44 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Deaf Smith and 10 more91 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.