Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 787

May 11, 201247 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 11, 2012, 2:13 PM CDT for 47 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 11, 2012, 2:13 PM CDT (19:13 UTC)
Expired
May 11, 2012, 4:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 47 counties

Atascosa County, TX, Austin County, TX, Bandera County, TX, Bastrop County, TX, Bell County, TX, Bexar County, TX, Blanco County, TX, Brazos County, TX, Burleson County, TX, Burnet County, TX, Caldwell County, TX, Colorado County, TX, Comal County, TX, Coryell County, TX, DeWitt County, TX, Falls County, TX, Fayette County, TX, Frio County, TX, Gillespie County, TX, Gonzales County, TX, Grimes County, TX, Guadalupe County, TX, Hays County, TX, Houston County, TX, Karnes County, TX, Kendall County, TX, Kerr County, TX, Lampasas County, TX, Lavaca County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Llano County, TX, Madison County, TX, McLennan County, TX, Medina County, TX, Milam County, TX, Montgomery County, TX, Real County, TX, Robertson County, TX, Travis County, TX, Uvalde County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Williamson County, TX, Wilson County, TX

The radar

The Ft Hood radar (KGRK), 49 km from the middle of the area, began a volume at 19:14 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

Fort Worth, TX (KFWD), launched 12:00Z, 7.2 hours before the alert went out and 271 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 12:00Z on 2012-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 119 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 12:00Z on 2012-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.1939587897117Sfc1 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
119 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
617 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

500 
ACUS11 KWNS 111913
SWOMCD
SPC MCD 111913 
TXZ000-112115-

MESOSCALE DISCUSSION 0787
NWS STORM PREDICTION CENTER NORMAN OK
0213 PM CDT FRI MAY 11 2012

AREAS AFFECTED...CENTRAL TX VICINITY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 111913Z - 112115Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...SLOWLY INCREASING CONVECTION ACROSS THE CENTRAL TX AREA
MAY EVENTUALLY REQUIRE WW ISSUANCE.

DISCUSSION...VISIBLE SATELLITE IMAGERY CONTINUES TO REVEAL
INCREASING CUMULUS DEVELOPMENT ACROSS A LARGE PORTION OF TX...WITHIN
CYCLONIC FLOW FIELD SURROUNDING THE NWRN TX UPPER LOW.  WHILE
CAPPING S OF THE HILL COUNTRY CONTINUES TO HINDER
CONVECTION...STORMS HAVE DEVELOPED ACROSS N TX OVER THE PAST COUPLE
OF HOURS...AND EXPECT THIS DEVELOPMENT TO INCREASE SWD ACROSS
CENTRAL TX AS HEATING/DESTABILIZATION CONTINUES.  

UNLIKE AREAS FARTHER N...STRONGER BELT OF FLOW CIRCLING THE UPPER
LOW RESIDES ACROSS THE CENTRAL TX REGION...WHICH -- IN CONJUNCTION
WITH THE MORE SUBSTANTIAL DESTABILIZATION ACROSS THIS AREA --
SUGGEST GREATER SEVERE THREAT.  WHILE TIMING AND LOCATION REMAIN
DIFFICULT TO SPECIFY DUE TO LACK OF A WELL-DEFINED SURFACE FOCUSING
MECHANISM...THE ENTIRE CENTRAL TX AREA WILL CONTINUE TO BE MONITORED
FOR POSSIBLE WW ISSUANCE THIS AFTERNOON.

..GOSS/HART.. 05/11/2012

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

ATTN...WFO...HGX...FWD...CRP...EWX...SJT...

LAT...LON   31679666 31339529 29879553 28849755 28769969 29590005
            30179959 30769874 31659786 31679666

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 10, 7:18 PM CDTMesoscale DiscussionSPCAransas, Atascosa, Austin, Bastrop, Bee, Bexar and 43 more57 min
May 10, 7:50 PM CDTTornado WatchSPCAransas, Atascosa, Austin, Bastrop, Bee, Bell and 48 more9 hr
May 10, 9:42 PM CDTMesoscale DiscussionSPCAransas, Atascosa, Austin, Bastrop, Bee, Bell and 36 more63 min
May 10, 11:36 PM CDTMesoscale DiscussionSPCAransas, Brooks, Calhoun, Cameron, Hidalgo, Jackson and 13 more84 min
May 11, 1:40 AM CDTMesoscale DiscussionSPCAransas, Austin, Bee, Brazoria, Brooks, Calhoun and 25 more65 min
May 11, 2:41 AM CDTMesoscale DiscussionSPCCameron, Chambers, Galveston, Hidalgo, Jefferson, Kenedy and 3 more34 min
May 11, 1:22 PM CDTMesoscale DiscussionSPCAnderson, Bosque, Camp, Cherokee, Collin, Cooke and 28 more53 min
May 11, 5:18 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Austin, Bastrop, Bell, Blanco and 40 more87 min
May 11, 5:51 PM CDTMesoscale DiscussionSPCBee, Brooks, Duval, Goliad, Hidalgo, Jim Hogg and 7 more84 min

Nearby

Mesoscale Discussions in Texas, 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.