Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 685

May 19, 2021Hidalgo County, Jim Hogg County, Starr County, Texas

The Storm Prediction Center issued this mesoscale discussion at May 19, 2021, 7:09 AM CDT for Hidalgo County, Jim Hogg County, Starr County, Texas. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: May 19, 2021, 7:09 AM CDT (12:09 UTC)
Expired: May 19, 2021, 8:45 AM CDT
In force: 96 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 191

Counties Hidalgo County, TX, Jim Hogg County, TX, Starr County, TX

The radar

The Brownsville radar (KBRO), 121 km from the middle of the area, began a volume at 12:10 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

Brownsville Intl, TX (KBRO), launched 12:00Z, 0.2 hours before the alert went out and 123 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: 3667 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 504 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 122 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.3

Open this sounding in Storm Lab

The text

As transmitted.

026 
ACUS11 KWNS 191210
SWOMCD
SPC MCD 191209 
TXZ000-191345-

Mesoscale Discussion 0685
NWS Storm Prediction Center Norman OK
0709 AM CDT Wed May 19 2021

Areas affected...south Texas

Concerning...Severe Thunderstorm Watch 191...

Valid 191209Z - 191345Z

The severe weather threat for Severe Thunderstorm Watch 191
continues.

SUMMARY...Damaging wind potential appears to be increasing across
parts of south Texas near the Rio Grande. Damaging gusts are
possible over the next couple of hours.

DISCUSSION...A cluster of thunderstorms west of McAllen along the
Rio Grande is becoming better organized this morning, taking on a
more intense bowing characteristic in radar imagery. Some evidence
of a developing rear inflow jet is evident in radar loops over the
past 20-30 minutes. Downstream, a very unstable airmass is in place,
with the BRO 12z RAOB indicating close to 4000 J/kg SBCAPE. Locally
intense winds are possible near the Rio Grande vicinity in southern
Starr and Hidalgo counties over the next hour or so. The bow will
continue to develop eastward at around 40kt, approaching Brownsville
by around 14-15z.

..Leitman.. 05/19/2021

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

ATTN...WFO...BRO...

LAT...LON   26689921 27069886 27069852 26939818 26599765 26169755
            25959765 25909792 25969846 25989865 26089920 26439932
            26689921

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 18, 7:34 PM CDT	Tornado Watch	SPC	Austin, Bee, Brazoria, Chambers, Colorado, Fort Bend and 17 more	6 hr
May 18, 8:00 PM CDT	Mesoscale Discussion	SPC	Cherokee, Gregg, Harrison, Marion, Nacogdoches, Panola and 4 more	60 min
May 18, 8:54 PM CDT	Mesoscale Discussion	SPC	Austin, Fort Bend, Harris, Jackson, Montgomery, Waller and 1 more	96 min
May 18, 10:39 PM CDT	Mesoscale Discussion	SPC	Hardin, Jasper, Jefferson, Newton, Orange, Tyler	96 min
May 18, 11:00 PM CDT	Mesoscale Discussion	SPC	Dimmit, Duval, Jim Hogg, La Salle, Webb, Zapata	90 min
May 19, 3:32 AM CDT	Mesoscale Discussion	SPC	Brooks, Dimmit, Duval, Hidalgo, Jim Hogg, Jim Wells and 5 more	118 min
May 19, 5:24 AM CDT	Severe Thunderstorm Watch	SPC	Brooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 8 more	8 hr
May 19, 8:46 AM CDT	Mesoscale Discussion	SPC	Brooks, Cameron, Hidalgo, Kenedy, Willacy	89 min
May 19, 2:10 PM CDT	Mesoscale Discussion	SPC	Callahan, Coke, Coleman, Concho, Crane, Crockett and 24 more	3 hr
May 19, 6:06 PM CDT	Mesoscale Discussion	SPC	Crane, Crockett, Ector, Glasscock, Irion, Midland and 6 more	84 min

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.