Alert archive / Texas / Mesoscale Discussions in 2003

Mesoscale Discussion 2140

August 11, 200333 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 11, 2003, 11:31 AM CDT for 33 counties in Texas. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Aug 11, 2003, 11:31 AM CDT (16:31 UTC)
Expired
Aug 11, 2003, 1:00 PM CDT
In force
89 min
Issued by
the Storm Prediction Center
All 33 counties

Austin County, TX, Bastrop County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Chambers County, TX, Colorado County, TX, DeWitt County, TX, Fayette County, TX, Fort Bend County, TX, Goliad County, TX, Gonzales County, TX, Grimes County, TX, Guadalupe County, TX, Harris County, TX, Hays County, TX, Jackson County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Montgomery County, TX, Polk County, TX, Refugio County, TX, San Jacinto County, TX, Travis County, TX, Victoria County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Williamson County, TX, Wilson 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

Corpus Christi, TX (KCRP), launched 12:00Z, 4.5 hours before the alert went out and 247 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, Corpus Christi, TX at 12:00Z on 2003-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1123 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, Corpus Christi, TX at 12:00Z on 2003-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
1123 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
798 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
21 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

746 
ACUS11 KWNS 111631
SWOMCD
SPC MCD 111631 
TXZ000-111800-

MESOSCALE DISCUSSION 2140
NWS STORM PREDICTION CENTER NORMAN OK
1131 AM CDT MON AUG 11 2003

AREAS AFFECTED...PORTIONS OF SERN TX

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 111631Z - 111800Z

THUNDERSTORMS WILL CONTINUE TO MOVE SWD ACROSS SERN TX WITH ACTIVITY
INCREASING IN INTENSITY/COVERAGE DURING THE NEXT FEW HOURS.  WW MAY
BE REQUIRED IN THE NEXT HOUR.

REGIONAL RADARS SHOW STORMS OVER HOUSTON/TRINITY COUNTIES WITH
ADDITIONAL STORMS DEVELOPING WWD ALONG A SURFACE BOUNDARY EXTENDING
INTO ROBERTSON COUNTY TO CENTRAL/WRN TX.  THE STRONGEST STORMS OVER
HOUSTON/TRINITY COUNTIES ARE TRACKING SSEWD ALONG A N-S ORIENTED AND
WWD MOVING OUTFLOW BOUNDARY FROM CONVECTION OVER ERN TX/SWRN LA. 
CLEAR SKIES SOUTH AND WEST OF SURFACE BOUNDARIES HAS ALLOWED THE AIR
MASS TO BECOME MODERATELY UNSTABLE /MLCAPE UP TO 2000 J/KG/.  DEEP
LAYER SHEAR AROUND 25 KT WILL FAVOR MULTICELL STORMS WITH ACTIVITY
LIKELY INCREASING IN INTENSITY/COVERAGE AS STORMS CONTINUE TO
DEVELOP AND MOVE SWD INTO A MORE UNSTABLE AIR MASS.

..PETERS.. 08/11/2003

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

ATTN...WFO...LCH...HGX...FWD...CRP...EWX...

30619802 31069490 29529438 28289714 29309826

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 11, 12:05 PM CDTSevere Thunderstorm WatchSPCAustin, Brazoria, Colorado, Fort Bend, Galveston, Harris and 8 more6 hr
Aug 11, 2:06 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Collin, Cooke, Dallas and 31 more54 min
Aug 11, 2:31 PM CDTMesoscale DiscussionSPCAtascosa, Austin, Bandera, Bastrop, Bee, Bexar and 44 more29 min
Aug 11, 2:35 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bastrop, Bee, Bexar, Blanco and 21 more5 hr
Aug 11, 4:45 PM CDTSevere Thunderstorm WatchSPCBosque, Clay, Collin, Comanche, Cooke, Dallas and 17 more5 hr
Aug 11, 5:16 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Austin, Brazoria, Brazos, Chambers and 21 more59 min
Aug 11, 5:29 PM CDTMesoscale DiscussionSPCCollin, Dallas, Ellis, Grayson, Navarro, Rockwall2 hr
Aug 11, 6:09 PM CDTMesoscale DiscussionSPCAransas, Atascosa, Bandera, Bastrop, Bee, Bexar and 42 more96 min

Nearby

Mesoscale Discussions in Texas, 2003Every mesoscale discussion in 2003

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.