Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 751

May 11, 201133 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 11, 2011, 11:25 PM CDT for 33 counties in Texas. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
May 11, 2011, 11:25 PM CDT (04:25 UTC)
Expired
May 12, 2011, 12:30 AM CDT
In force
65 min
Issued by
the Storm Prediction Center
All 33 counties

Austin County, TX, Bandera County, TX, Bastrop County, TX, Bexar County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Colorado County, TX, Comal County, TX, Falls County, TX, Fayette County, TX, Fort Bend County, TX, Gonzales County, TX, Grimes County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Lavaca County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, Medina County, TX, Milam County, TX, Real County, TX, Robertson County, TX, Travis County, TX, Uvalde County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Wilson County, TX, Zavala County, TX

The radar

The Ft Hood radar (KGRK), 40 km from the middle of the area, began a volume at 04:24 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

Fort Worth, TX (KFWD), launched 00:00Z, 4.4 hours before the alert went out and 268 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, Fort Worth, TX at 00:00Z on 2011-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 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, Fort Worth, TX at 00:00Z on 2011-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 270 square meters per square second.19395878Sfc1 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
26 J/kg
Mixed-layer CIN
-441 J/kg
Mixed-layer LCL
1482 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
270 m²/s²
0-3 km storm-relative helicity
219 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.

792 
ACUS11 KWNS 120426
SWOMCD
SPC MCD 120425
TXZ000-120530-

MESOSCALE DISCUSSION 0751
NWS STORM PREDICTION CENTER NORMAN OK
1125 PM CDT WED MAY 11 2011

AREAS AFFECTED...EAST-CENTRAL/SOUTH-CENTRAL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 120425Z - 120530Z

AT LEAST AN ISOLATED SEVERE THREAT WILL LIKELY CONTINUE
OVERNIGHT...AND A NEW WATCH WILL NEED TO BE CONSIDERED FOR PORTIONS
OF SOUTH-CENTRAL/PERHAPS EAST-CENTRAL TX.

AN ONGOING SEVERE TSTM NEARING I-35 BETWEEN NEW BRAUNFELS/AUSTIN AS
OF 0415Z HAS EXHIBITED SOME SUPERCELL CHARACTERISTICS OVER THE PAST
HOUR. SIMILAR TO THIS STORM...IT IS CONCEIVABLE THAT ADDITIONAL
SURFACE BASED DEVELOPMENT WILL CONTINUE TO OCCUR ALONG A SOUTHEAST
SAGGING OUTFLOW BOUNDARY WITHIN A RATHER MOIST AND WEAKLY
CAPPED/VERY UNSTABLE AIRMASS...WITH CINH EXPECTED TO ONLY WEAKEN
OVERNIGHT PER SHORT TERM PROGS. WSR-88D VWP DATA FROM EWX/GRX
REFLECT AMPLE VEERING/WIND SPEEDS FOR UPDRAFT
ROTATION/SUPERCELLS...ACCENTUATED BY 150-200 M2/S2 0-1 KM
SRH...WHICH IMPLIES A BRIEF TORNADO CANNOT BE RULED OUT IN VICINITY
OF THE SURFACE BOUNDARY ASIDE FROM LARGE HAIL.
ADDITIONALLY...VARIOUS NUMERICAL GUIDANCE...SUCH AS THE 00Z NAM/GFS
AND VARIOUS 21Z SREF MEMBERSHIP...IMPLY AN EAST-SOUTHEASTWARD
CONTINUATION OF DEEP CONVECTION TOWARD THE MIDDLE/UPPER TX
COAST...AND/OR MORE SO THE POSSIBILITY OF ADDITIONAL DEVELOPMENT
LATE TONIGHT/EARLY THURSDAY IN VICINITY OF THE RIO GRANDE.

..GUYER.. 05/12/2011

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

ATTN...WFO...HGX...FWD...EWX...

LAT...LON   30959736 31739650 31629574 29279573 28800030 29810021
            30359783 30959736

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 11, 7:43 PM CDTMesoscale DiscussionSPCAnderson, Bell, Blanco, Bowie, Burnet, Camp and 20 more62 min
May 12, 2:57 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 25 more33 min
May 12, 3:18 AM CDTSevere Thunderstorm WatchSPCBandera, Dimmit, Edwards, Frio, Kerr, Kinney and 7 more5 hr
May 12, 7:27 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bee, Bexar, Brooks, Dimmit and 26 more33 min
May 12, 7:52 AM CDTSevere Thunderstorm WatchSPCAransas, Atascosa, Bandera, Bee, Bexar, Brooks and 33 more9 hr
May 12, 8:46 AM CDTMesoscale DiscussionSPCBastrop, Bell, Bosque, Brazos, Burleson, Caldwell and 22 more59 min
May 12, 9:02 AM CDTSevere Thunderstorm WatchSPCAnderson, Austin, Bastrop, Bell, Blanco, Bosque and 53 more6 hr
May 12, 11:43 AM CDTMesoscale DiscussionSPCAnderson, Aransas, Austin, Bee, Brazos, Burleson and 33 more92 min
May 12, 1:46 PM CDTMesoscale DiscussionSPCFannin, Grayson, Lamar119 min
May 12, 3:17 PM CDTSevere Thunderstorm WatchSPCCooke, Fannin, Grayson, Lamar, Montague, Red River7 hr
May 12, 6:30 PM CDTMesoscale DiscussionSPCCooke, Fannin, Grayson, Lamar90 min

Nearby

Mesoscale Discussions in Texas, 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.