Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 444

April 27, 202111 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2021, 10:39 PM CDT for 11 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 27, 2021, 10:39 PM CDT (03:39 UTC)
Expired: Apr 28, 2021, 12:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 115

Counties Andrews County, TX, Borden County, TX, Crane County, TX, Dawson County, TX, Ector County, TX, Howard County, TX, Martin County, TX, Midland County, TX, Mitchell County, TX, Scurry County, TX, Winkler County, TX

The radar

The Midland/Odessa radar (KMAF), 15 km from the middle of the area, began a volume at 03:40 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

Midland Regional, TX (KMAF), launched 00:00Z, 3.7 hours before the alert went out and 14 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: 18 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 3768 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

016 
ACUS11 KWNS 280340
SWOMCD
SPC MCD 280339 
TXZ000-NMZ000-280545-

Mesoscale Discussion 0444
NWS Storm Prediction Center Norman OK
1039 PM CDT Tue Apr 27 2021

Areas affected...Parts of the Pecos Valley into Texas South Plains

Concerning...Severe Thunderstorm Watch 115...

Valid 280339Z - 280545Z

The severe weather threat for Severe Thunderstorm Watch 115
continues.

SUMMARY...A period of rapid thunderstorm development and
intensification is possible around the Midland area by Midnight-1 AM
CDT, if not before.  This may include the evolution of a supercell
or two, which could pose a risk for large, damaging hail, along with
potentially damaging wind gusts.

DISCUSSION...A south-southeasterly low-level jet is in the process
of strengthening to the east of the Pecos River.  Downstream of the
primary short wave trough now turning east-southeastward near the
Southwestern international border area, this is forecast to continue
into the 05-07Z time frame.  At the same time, it appears that
another more modest preceding perturbation may emerge from the
northern Mexican Plateau, and contribute to increasing forcing for
ascent across the Pecos Valley into South Plains vicinity. 

A general increase in convection is already underway across this
region, focused along the dryline and the southern fringe of a zone
of stronger warm advection (around 700 mb).  Inhibition associated
with warm elevated mixed-layer air may still be suppressing
convective development, but various model output suggests that this
may weaken considerably during the next few hours.  The increasing
large-scale ascent, coupled with deepening boundary-layer moisture
return beneath steep mid-level lapse rates, may support a period of
rapid thunderstorm development and intensification by 05-06Z, if not
before.  Initially this may include supercells around the Midland
area, before activity tends to consolidate and grow upscale while
propagating east-northeastward near the Interstate 20 corridor.

..Kerr.. 04/28/2021

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

ATTN...WFO...SJT...LUB...MAF...

LAT...LON   32030307 32700227 33290085 32270080 31620204 30570308
            32030307

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 27, 8:01 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Clay, Fisher, Haskell, Jones and 10 more	89 min
Apr 27, 8:23 PM CDT	Severe Thunderstorm Watch	SPC	Andrews, Archer, Baylor, Borden, Clay, Coke and 29 more	7 hr
Apr 28, 1:38 AM CDT	Mesoscale Discussion	SPC	Callahan, Coke, Coleman, Eastland, Glasscock, Jones and 10 more	2 hr
Apr 28, 3:01 AM CDT	Tornado Watch	SPC	Archer, Baylor, Callahan, Clay, Cooke, Eastland and 14 more	7 hr
Apr 28, 6:35 AM CDT	Mesoscale Discussion	SPC	Archer, Callahan, Clay, Cooke, Eastland, Jack and 9 more	3 hr
Apr 28, 9:25 AM CDT	Mesoscale Discussion	SPC	Cooke, Denton, Grayson, Parker, Wise	65 min
Apr 28, 1:14 PM CDT	Mesoscale Discussion	SPC	Brown, Callahan, Coleman, Comanche, Cooke, Denton and 14 more	2 hr
Apr 28, 1:57 PM CDT	Tornado Watch	SPC	Brown, Callahan, Coke, Coleman, Comanche, Concho and 16 more	9 hr
Apr 28, 2:42 PM CDT	Mesoscale Discussion	SPC	Bandera, Blanco, Edwards, Gillespie, Kendall, Kerr and 9 more	2 hr
Apr 28, 3:10 PM CDT	Tornado Watch	SPC	Atascosa, Bandera, Bexar, Blanco, Comal, Dimmit and 23 more	8 hr
Apr 28, 3:40 PM CDT	Mesoscale Discussion	SPC	Brown, Callahan, Coleman, Comanche, Eastland, Runnels and 2 more	95 min
Apr 28, 5:41 PM CDT	Mesoscale Discussion	SPC	Bandera, Bexar, Frio, Kendall, Kinney, Maverick and 4 more	2 hr
Apr 28, 6:01 PM CDT	Mesoscale Discussion	SPC	Lamar	119 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.