Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 388

April 15, 202115 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2021, 10:56 AM CDT for 15 counties in Texas. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Apr 15, 2021, 10:56 AM CDT (15:56 UTC)
Expired
Apr 15, 2021, 12:30 PM CDT
In force
94 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 96

Counties Bandera County, TX, Concho County, TX, Edwards County, TX, Gillespie County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Real County, TX, Schleicher County, TX, Sutton County, TX, Tom Green County, TX, Uvalde County, TX

The radar

The Laughlin AFB radar (KDFX), 119 km from the middle of the area, began a volume at 15:58 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, 3.9 hours before the alert went out and 128 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 2021-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2593 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 2021-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 169 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
2593 J/kg
Mixed-layer CIN
-44 J/kg
Mixed-layer LCL
634 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
169 m²/s²
0-3 km storm-relative helicity
338 m²/s²
Significant tornado parameter
4.6
Supercell composite
21.4

Open this sounding in Storm Lab

The text

As transmitted.

873 
ACUS11 KWNS 151556
SWOMCD
SPC MCD 151556 
TXZ000-151730-

Mesoscale Discussion 0388
NWS Storm Prediction Center Norman OK
1056 AM CDT Thu Apr 15 2021

Areas affected...portions of the Concho Valley and Edwards Plateau
region of Texas

Concerning...Severe Thunderstorm Watch 96...

Valid 151556Z - 151730Z

The severe weather threat for Severe Thunderstorm Watch 96
continues.

SUMMARY...Risk for primarily large hail continues across WW 96.

DISCUSSION...Latest radar loop shows isolated supercells ongoing
across portions of WW 96 -- including portions of the Concho Valley
and Edwards Plateau region.  Several left splits have occurred --
supported by a rather long/straight hodograph in the elevated
cloud-bearing layer.

The storms are occurring in an area of warm advection north of the
surface cold front, but with a slight weakening of the southerly
low-level jet forecast to occur with time, expect storm coverage to
remain isolated this afternoon.  

Still, steep lapse rates and the aforementioned/sufficient shear
will continue to support risk for large hail with any storms which
do persist.

..Goss.. 04/15/2021

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   31530070 31590018 31229916 30959872 30129881 29179955
            29129978 29030088 29190121 30010100 30560082 31530070

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 15, 8:17 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Blanco, Comal, Edwards and 13 more2 hr
Apr 15, 8:36 AM CDTSevere Thunderstorm WatchSPCBandera, Blanco, Burnet, Concho, Crockett, Edwards and 19 more8 hr
Apr 15, 12:24 PM CDTMesoscale DiscussionSPCBastrop, Bell, Blanco, Burnet, Coryell, Falls and 12 more2 hr
Apr 15, 4:55 PM CDTMesoscale DiscussionSPCAustin, Brazoria, Burleson, Fort Bend, Harris, Lee and 4 more3 hr

Nearby

Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021

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.