Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 2190

September 18, 201112 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 18, 2011, 6:18 PM CDT for 12 counties in Texas. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Sep 18, 2011, 6:18 PM CDT (23:18 UTC)
Expired
Sep 18, 2011, 7:15 PM CDT
In force
57 min
Issued by
the Storm Prediction Center

Counties Bandera County, TX, Bexar County, TX, Blanco County, TX, Comal County, TX, Edwards County, TX, Hays County, TX, Kendall County, TX, Kerr County, TX, Kinney County, TX, Medina County, TX, Real County, TX, Uvalde County, TX

The radar

The Laughlin AFB radar (KDFX), 113 km from the middle of the area, began a volume at 23:20 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

Del Rio, TX (KDRT), launched 12:00Z, 11.3 hours before the alert went out and 158 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, Del Rio, TX at 12:00Z on 2011-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1433 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, Del Rio, TX at 12:00Z on 2011-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 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
1433 J/kg
Mixed-layer CIN
-96 J/kg
Mixed-layer LCL
566 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.7

Open this sounding in Storm Lab

The text

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

610 
ACUS11 KWNS 182318
SWOMCD
SPC MCD 182318 
TXZ000-190015-

MESOSCALE DISCUSSION 2190
NWS STORM PREDICTION CENTER NORMAN OK
0618 PM CDT SUN SEP 18 2011

AREAS AFFECTED...PORTIONS OF CNTRL/S-CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 182318Z - 190015Z

AN ISOLATED HAIL/WIND THREAT MAY MATERIALIZE THIS EVENING ACROSS
PORTIONS OF CNTRL/S-CNTRL TX. CONVECTIVE TRENDS ARE BEING
MONITORED...BUT A WW APPEARS UNLIKELY ATTM. 

RECENT RADAR LOOP SHOWS SEVERAL SMALL TSTM CLUSTERS SLOWLY
PROPAGATING SWD ACROSS CNTRL TX. THESE TSTMS ARE MOVING INTO AN
UNSTABLE /MLCAPE 2000-2500 J/KG/ AND WEAKLY CAPPED AIR MASS...WHICH
SHOULD CONTINUE TO SUPPORT FURTHER SWD PROPAGATION. DESPITE THE
PRESENCE OF RATHER WEAK 0-6 KM FLOW...SLY LOW-LEVEL FLOW BENEATH
NWLY MIDLEVEL FLOW IS YIELDING MODEST EFFECTIVE VERTICAL SHEAR /NEAR
30 KTS PER 23Z RUC OBJECTIVE ANALYSIS/ WHICH SHOULD MAINTAIN
MULTICELLULAR STRUCTURE. HOWEVER...WITH STRONGEST FORCED ASCENT
ASSOCIATED WITH AN UPPER WAVE SITUATED WELL N OF THE REGION...AND
TSTMS MOVING OFF THE SFC COLD FRONT...PROPAGATION WILL PRIMARILY BE
COLD-POOL DRIVEN AND WILL ONLY YIELD A LOCALIZED WIND/HAIL THREAT.
DUE TO THE EXPECTED ISOLATED/MARGINAL NATURE OF THE SVR THREAT...A
WW IS NOT ANTICIPATED.

..ROGERS.. 09/18/2011

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

ATTN...WFO...EWX...

LAT...LON   29459833 29239875 29139948 29170029 29430071 29830080
            30170060 30230011 30229940 30339891 30409849 30389802
            30029784 29459833

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 10:17 PM CDTMesoscale DiscussionSPCCooke, Grayson, Montague, Wise88 min
Sep 18, 3:59 PM CDTMesoscale DiscussionSPCBosque, Brown, Callahan, Coleman, Collin, Comanche and 46 more31 min
Sep 18, 4:06 PM CDTSevere Thunderstorm WatchSPCAnderson, Bosque, Brown, Callahan, Coke, Coleman and 51 more9 hr
Sep 18, 5:41 PM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Cherokee, Franklin, Gregg and 12 more7 hr
Sep 18, 6:48 PM CDTMesoscale DiscussionSPCLamar, Red River57 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.