Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 866

June 7, 20219 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jun 7, 2021, 7:19 AM CDT for 9 counties in Texas. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued
Jun 7, 2021, 7:19 AM CDT (12:19 UTC)
Expired
Jun 7, 2021, 9:15 AM CDT
In force
116 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 241

Counties Callahan County, TX, Comanche County, TX, Eastland County, TX, Erath County, TX, Hood County, TX, Johnson County, TX, Parker County, TX, Somervell County, TX, Tarrant County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 84 km from the middle of the area, began a volume at 12:19 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

Fort Worth, TX (KFWD), launched 12:00Z, 0.3 hours before the alert went out and 89 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, Fort Worth, TX at 12:00Z on 2021-06-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1851 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, Fort Worth, TX at 12:00Z on 2021-06-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.1939Sfc1 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
1851 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
635 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

As transmitted.

557 
ACUS11 KWNS 071219
SWOMCD
SPC MCD 071219 
TXZ000-071415-

Mesoscale Discussion 0866
NWS Storm Prediction Center Norman OK
0719 AM CDT Mon Jun 07 2021

Areas affected...Parts of north central Texas

Concerning...Severe Thunderstorm Watch 241...

Valid 071219Z - 071415Z

The severe weather threat for Severe Thunderstorm Watch 241
continues.

SUMMARY...While the severe weather risk has diminished in the near
term, potential exists for substantive renewed intensification and
organization, which may lead to increasing risk for severe hail and
strong surface gusts near or just south of the Dallas-Fort Worth
Metroplex by 9-11 AM CDT.

DISCUSSION...Strongest new thunderstorm development has become
focused on the southern/southwestern flank of conglomerate
convective outflow.  This is where large-scale ascent is supported
by weak lower/mid tropospheric warm advection, along the
northeastern periphery of warmer and more strongly capping elevated
mixed-layer air.  This is also beneath modest to weak westerly to
northwesterly flow, in the wake of weak large-scale mid-level
troughing slowly shifting into the Mississippi Valley.  The remnant
nocturnal low-level jet probably contributed to enhancement of this
lift, but this forcing is in the process of weakening.

Still, with a continued slow southward suppression of the elevated
mixed-layer air across north central Texas, coupled with a gradual
warming of the seasonably moist boundary layer characterized by
mixed-layer CAPE in excess of 3000 J/kg, there appears potential for
substantive thunderstorm intensification and upscale growth through
14-16Z.   Intersecting outflow surges from one remnant cluster of
storms now northwest of the Dallas-Fort Worth Metroplex, and the
newer cluster to the west, may provide one potential focus for
intensifying and increasingly organized convection near or just
south of Fort Worth.  Given the environment, this gradually may be
accompanied by strengthening rear inflow/downdrafts and increasing
potential for strong surface gusts.

..Kerr.. 06/07/2021

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

ATTN...WFO...FWD...SJT...

LAT...LON   32599858 32839817 32969782 33039748 33019712 32479679
            31669869 32119951 32549923 32599858

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 6, 8:49 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Castro, Crosby, Dawson and 14 more116 min
Jun 6, 9:42 PM CDTSevere Thunderstorm WatchSPCArmstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 22 more6 hr
Jun 6, 11:47 PM CDTMesoscale DiscussionSPCBriscoe, Cottle, Crosby, Dickens, Floyd, Garza and 8 more88 min
Jun 7, 1:37 AM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Childress, Coleman, Cottle and 20 more83 min
Jun 7, 2:48 AM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Callahan, Clay, Cooke, Denton and 17 more7 hr
Jun 7, 4:12 AM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Foard, Hardeman, Haskell and 12 more93 min
Jun 7, 9:36 AM CDTMesoscale DiscussionSPCAnderson, Angelina, Bosque, Cherokee, Ellis, Falls and 16 more2 hr
Jun 7, 12:32 PM CDTSevere Thunderstorm WatchSPCAngelina, Bowie, Camp, Cass, Cherokee, Franklin and 24 more6 hr
Jun 7, 3:08 PM CDTMesoscale DiscussionSPCSabine, San Augustine, Shelby2 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.