Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 585

May 10, 20218 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 10, 2021, 5:47 PM CDT for 8 counties in Texas. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: May 10, 2021, 5:47 PM CDT (22:47 UTC)
Expired: May 10, 2021, 7:15 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

Counties Brazos County, TX, Grimes County, TX, Jasper County, TX, Montgomery County, TX, Polk County, TX, San Jacinto County, TX, Tyler County, TX, Walker County, TX

The radar

The Houston radar (KHGX), 133 km from the middle of the area, began a volume at 22:48 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.8 hours before the alert went out and 204 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: 1821 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 536 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 147 m²/s²
0-3 km storm-relative helicity: 243 m²/s²
Significant tornado parameter: 2.2
Supercell composite: 11.6

Open this sounding in Storm Lab

The text

As transmitted.

895 
ACUS11 KWNS 102248
SWOMCD
SPC MCD 102247 
TXZ000-110015-

Mesoscale Discussion 0585
NWS Storm Prediction Center Norman OK
0547 PM CDT Mon May 10 2021

Areas affected...Portions of eastern Texas

Concerning...Severe potential...Watch unlikely 

Valid 102247Z - 110015Z

Probability of Watch Issuance...20 percent

SUMMARY...A few strong to severe storms possible through the
evening. Large hail will be the primary threat.

DISCUSSION...Storms have formed along a nearly stationary frontal
boundary in eastern Texas. The airmass south of this boundary is
very unstable with MLCAPE around 2500 to 3000 J/kg. Additionally,
effective shear of 45 to 50 knots will be sufficient for updraft
organization. However, storm intensity may remain muted due to the
storm orientation and competing updrafts as well as a tendency for
storms to drift to the cool side of the boundary and become
elevated. Due to these factors, the greatest severe weather threat
will likely be on the western periphery of the cluster as it grows
upscale where the best instability and best chance for uninterrupted
updrafts will be. A few large hail and damaging wind reports may be
possible, but the threat is expected to remain too
localized/isolated to necessitate a watch

..Bentley/Hart.. 05/10/2021

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

ATTN...WFO...LCH...SHV...HGX...

LAT...LON   30889622 31179476 31039395 30859377 30659372 30409447
            30269558 30279612 30339626 30539644 30889622

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 9, 8:06 PM CDT	Mesoscale Discussion	SPC	Anderson, Bell, Blanco, Bosque, Burnet, Comal and 32 more	114 min
May 10, 10:28 AM CDT	Mesoscale Discussion	SPC	Delta, Fannin, Grayson, Lamar, Red River	92 min
May 10, 1:04 PM CDT	Mesoscale Discussion	SPC	Edwards, Kinney, Real, Terrell, Val Verde	116 min
May 10, 1:48 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bexar, Crockett, Dimmit, Edwards and 14 more	10 hr
May 10, 2:07 PM CDT	Mesoscale Discussion	SPC	Grimes, Houston, Madison, Polk, San Jacinto, Trinity and 2 more	113 min
May 10, 6:05 PM CDT	Mesoscale Discussion	SPC	Bee, Dimmit, Duval, Jim Wells, La Salle, Live Oak and 2 more	2 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.