Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 796

May 28, 202111 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 28, 2021, 10:15 PM CDT for 11 counties in Texas. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
May 28, 2021, 10:15 PM CDT (03:15 UTC)
Expired
May 28, 2021, 11:45 PM CDT
In force
90 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 221

Counties Bee County, TX, Brazoria County, TX, Calhoun County, TX, Fort Bend County, TX, Goliad County, TX, Jackson County, TX, Karnes County, TX, Matagorda County, TX, Refugio County, TX, Victoria County, TX, Wharton County, TX

The radar

The Austin/San Antonio radar (KEWX), 130 km from the middle of the area, began a volume at 03:16 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

Corpus Christi, TX (KCRP), launched 00:00Z, 3.3 hours before the alert went out and 134 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 00:00Z on 2021-05-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2506 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 00:00Z on 2021-05-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 square meters per square second.193958Sfc1 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
2506 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
712 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
115 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

694 
ACUS11 KWNS 290316
SWOMCD
SPC MCD 290315 
TXZ000-290445-

Mesoscale Discussion 0796
NWS Storm Prediction Center Norman OK
1015 PM CDT Fri May 28 2021

Areas affected...Parts of south central Texas into middle Texas
coastal areas

Concerning...Severe Thunderstorm Watch 221...

Valid 290315Z - 290445Z

The severe weather threat for Severe Thunderstorm Watch 221
continues.

SUMMARY...Thunderstorm intensities, in general, are beginning to
diminish, but the risk for strong surface gusts will continue with
lingering storms spreading into middle Texas coastal areas through
Midnight-1 AM CDT.

DISCUSSION...A large convective system, including one embedded MCV
currently southwest of College Station, and a trailing downburst
producing cluster (with a recorded SAT ASOS gust to 67 kt)
east-southeast of San Antonio, continues a south-southeastward
propagation toward middle Texas coastal areas.  Activity has
exhibited recent, general weakening trends, and probably is being
limited by the lack of stronger low-level southerly ambient flow. 
However, the inflow environment remains characterized by sizable
CAPE in excess of 2000 J/kg, in the presence of modest deep-layer
shear.  And there appears potential for strong surface gusts to
develop to the south of the MCV, to the west and south of the
Greater Houston area, with additional updraft intensification and
locally strong downburst development still possible along the
trailing composite outflow boundary into the Palacios vicinity
through 04-06Z.

..Kerr.. 05/29/2021

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

ATTN...WFO...HGX...CRP...EWX...

LAT...LON   29169823 29059735 29199635 29729565 29049516 28489606
            28269694 28269784 28719868 29169823

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 28, 7:18 PM CDTMesoscale DiscussionSPCCrane, Crockett, Ector, Kimble, Reagan, Schleicher and 4 more87 min
May 28, 7:40 PM CDTSevere Thunderstorm WatchSPCAndrews, Bailey, Borden, Castro, Cochran, Crosby and 16 more6 hr
May 28, 7:58 PM CDTMesoscale DiscussionSPCBandera, Bexar, Comal, Gonzales, Guadalupe, Medina and 2 more2 hr
May 28, 9:12 PM CDTMesoscale DiscussionSPCAndrews, Gaines, Hockley, Lubbock, Lynn, Terry93 min
May 28, 11:22 PM CDTMesoscale DiscussionSPCCrane, Pecos, Reeves, Upton, Ward, Winkler113 min
May 29, 1:34 AM CDTMesoscale DiscussionSPCCrockett, Dimmit, Edwards, Frio, Kimble, Kinney and 10 more2 hr
May 29, 10:09 AM CDTMesoscale DiscussionSPCBrooks, Cameron, Hidalgo, Jim Hogg, Kenedy, Starr and 1 more96 min
May 29, 2:51 PM CDTMesoscale DiscussionSPCCulberson, Hudspeth, Jeff Davis, Loving, Presidio, Reeves114 min
May 29, 6:30 PM CDTMesoscale DiscussionSPCDallam, Hartley, Moore90 min

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.