Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 249

March 24, 20216 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 24, 2021, 11:42 PM CDT for 6 counties in Texas. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Mar 24, 2021, 11:42 PM CDT (04:42 UTC)
Expired: Mar 25, 2021, 1:15 AM CDT
In force: 93 min
Issued by: the Storm Prediction Center
Concerning: Tornado watch 49

Counties Burnet County, TX, Coryell County, TX, Lampasas County, TX, Llano County, TX, Mason County, TX, San Saba County, TX

The radar

The Ft Hood radar (KGRK), 121 km from the middle of the area, began a volume at 04:45 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

Del Rio, TX (KDRT), launched 00:00Z, 4.7 hours before the alert went out and 267 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: 479 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 2767 m above ground
0-6 km bulk shear: 80 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 317 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

804 
ACUS11 KWNS 250443
SWOMCD
SPC MCD 250442 
TXZ000-250615-

Mesoscale Discussion 0249
NWS Storm Prediction Center Norman OK
1142 PM CDT Wed Mar 24 2021

Areas affected...central TX

Concerning...Tornado Watch 49...

Valid 250442Z - 250615Z

The severe weather threat for Tornado Watch 49 continues.

SUMMARY...Focused potential for 60-70 kt gusts over the next 1-2
hours as remnant supercell cores consolidate further into a band and
maintain some supercell characteristics.  The strongest gusts will
likely accompany the precipitation-loaded rear flank downdrafts as
this activity gradually pushes eastward over the next 1-2 hours.

DISCUSSION...Radar mosaic shows the early stages of upscale growth
over central TX with remnant supercell cores.  Area VAD data
(reference KEWX and KGRK) have shown a 10-15 kt increase during the
past hour at 3 km AGL (roughly 700 mb).  The storm cores will
continue to encounter a richer low-level airmass with surface
dewpoints in the lower 60s deg F.  As the cores continue to become
more precipitation loaded over the next hour, expecting a transition
from mainly a hail threat to a combination of hail/wind.  The wind
risk will seemingly maximize in the vicinity of where stronger
internal dynamic storm scale processes occur, and thereby favor
increasing potential for stronger gusts at the surface.  Given the
strengthening low to mid-level wind field and a favorable convective
mode transition, expecting an increased threat for 60-70 kt gusts
over the next 1-2 hours as this band of storms moves east.

..Smith.. 03/25/2021

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

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

LAT...LON   30309983 31659829 31619747 31099766 30619831 30259911
            30309983

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 24, 7:37 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Collin, Cooke, Dallas and 23 more	53 min
Mar 24, 8:15 PM CDT	Mesoscale Discussion	SPC	Bandera, Bell, Blanco, Bosque, Brown, Burnet and 29 more	2 hr
Mar 24, 9:52 PM CDT	Tornado Watch	SPC	Bandera, Bell, Bexar, Blanco, Bosque, Burnet and 37 more	6 hr
Mar 24, 10:28 PM CDT	Mesoscale Discussion	SPC	Edwards, Kimble	62 min
Mar 24, 11:37 PM CDT	Mesoscale Discussion	SPC	Bowie, Cass, Lamar, Morris, Red River, Titus	53 min
Mar 25, 1:40 AM CDT	Mesoscale Discussion	SPC	Anderson, Bandera, Bell, Bexar, Blanco, Bosque and 40 more	95 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.