Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 510

May 3, 20216 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 3, 2021, 8:30 PM CDT for 6 counties in Texas. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: May 3, 2021, 8:30 PM CDT (01:30 UTC)
Expired: May 3, 2021, 9:30 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 135

Counties Bexar County, TX, Blanco County, TX, Comal County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX

The radar

The Austin/San Antonio radar (KEWX), 18 km from the middle of the area, began a volume at 01:34 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, 1.5 hours before the alert went out and 241 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1737 J/kg
Mixed-layer CIN: -372 J/kg
Mixed-layer LCL: 1458 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

167 
ACUS11 KWNS 040130
SWOMCD
SPC MCD 040130 
TXZ000-040230-

Mesoscale Discussion 0510
NWS Storm Prediction Center Norman OK
0830 PM CDT Mon May 03 2021

Areas affected...South-central Texas

Concerning...Severe Thunderstorm Watch 135...

Valid 040130Z - 040230Z

The severe weather threat for Severe Thunderstorm Watch 135
continues.

SUMMARY...Large hail and damaging wind gusts will remain possible
through the next few hours with a couple supercells ongoing within
WW132.

DISCUSSION...As of 0110z, KEWX showed a large sueprcell
thunderstorm, producing numerous reports of severe hail, was located
above the San Antonio metro. A second, left moving supercell at the
Gillespie Blanco Kendall county intersection also has a history of
producing large hail, with several 2-2.5 inch reports along I-10 in
the last hour. These storms are ongoing in a very unstable and
moderately sheared environment with 3000-4000 J/kg of MUCAPE and
40-50 kts effective shear. Hi-res guidance and observation trends
suggest that a significant hail threat will remain likely with these
storms as they slowly move eastward in WW135. The greatest threat
corridor appears to be the eastern San Antonio metro and eastward
along interstate 10. Storms should slowly begin to weaken with the
loss of diurnal heating, but severe weather will remain likely
through 0300z.

..Lyons.. 05/04/2021

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

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

LAT...LON   29719763 29389767 29249785 29229808 29279839 29439873
            29739888 30289897 30429878 30449829 30209793 29939772
            29719763

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 3, 7:01 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bexar, Blanco, Burnet, Comal and 9 more	4 hr
May 3, 7:38 PM CDT	Mesoscale Discussion	SPC	Bosque, Collin, Dallas, Denton, Ellis, Fannin and 6 more	97 min
May 3, 8:38 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Gregg, Marion, Morris and 4 more	2 hr
May 3, 9:10 PM CDT	Mesoscale Discussion	SPC	Callahan, Eastland, Fisher, Haskell, Jones, Nolan and 6 more	95 min
May 3, 9:10 PM CDT	Severe Thunderstorm Watch	SPC	Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 10 more	7 hr
May 3, 9:52 PM CDT	Mesoscale Discussion	SPC	Anderson, Bell, Coryell, Ellis, Falls, Freestone and 12 more	53 min
May 3, 10:22 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Bell, Collin, Cooke, Dallas, Delta and 28 more	5 hr
May 3, 11:34 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Falls, Franklin, Freestone and 12 more	86 min
May 4, 6:44 AM CDT	Mesoscale Discussion	SPC	Anderson, Bell, Brazos, Burleson, Camp, Cass and 23 more	2 hr
May 4, 8:11 AM CDT	Severe Thunderstorm Watch	SPC	Angelina, Austin, Brazos, Burleson, Chambers, Colorado and 22 more	8 hr

Nearby

Mesoscale Discussions in Texas, 2021 Every 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.