Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 1011

June 13, 201711 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2017, 2:09 PM CDT for 11 counties in Texas. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jun 13, 2017, 2:09 PM CDT (19:09 UTC)
Expired
Jun 13, 2017, 4:45 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%

Counties Borden County, TX, Crane County, TX, Dawson County, TX, Ector County, TX, Glasscock County, TX, Howard County, TX, Martin County, TX, Midland County, TX, Pecos County, TX, Upton County, TX, Ward County, TX

The radar

The Midland/Odessa radar (KMAF), 71 km from the middle of the area, began a volume at 19:10 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

Midland Regional, TX (KMAF), launched 12:00Z, 7.2 hours before the alert went out and 71 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, Midland Regional, TX at 12:00Z on 2017-06-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 411 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, Midland Regional, TX at 12:00Z on 2017-06-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 76 square meters per square second.193958Sfc1 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
411 J/kg
Mixed-layer CIN
-494 J/kg
Mixed-layer LCL
1294 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

095 
ACUS11 KWNS 131910
SWOMCD
SPC MCD 131909 
TXZ000-132145-

Mesoscale Discussion 1011
NWS Storm Prediction Center Norman OK
0209 PM CDT Tue Jun 13 2017

Areas affected...Portions of southwest TX

Concerning...Severe potential...Watch possible 

Valid 131909Z - 132145Z

Probability of Watch Issuance...40 percent

SUMMARY...The area is being monitored for some severe thunderstorm
risk developing this afternoon and continuing into the evening.
Watch issuance will be possible.

DISCUSSION...Diurnally enhanced orographic circulations are
encouraging towering cumulus development over the Davis Mountains
and other southwest Texas mountains, on the east edges of nearly
dry-adiabatic lapse rates in the lowest 3 km above ground. This
initial convection should deepen, evolving into a couple of isolated
storms. Meanwhile, a dryline continues to sharpen from near the
southeast NM/southwest TX border southward to the international
border. This dryline will be a focused zone for additional,
possible, isolated thunderstorm development into the late afternoon
hours. However, stronger forcing for ascent, attendant to a midlevel
speed maximum advancing from the southern Rockies to the adjacent
Plains, will reside north of the area.

Nevertheless, sufficient deep shear peripheral to the speed 
maximum -- e.g., effective shear of 25-35 kt -- may support a few
sustained/organized cells (possible supercells) with severe
hail/wind possible. Storm motion will be somewhat erratic, with a
general slow eastward/southeastward spread of convection east of the
dryline into the evening hours. Upward convective-scale
accelerations will be bolstered by 8.0-8.5 C/km lapse rates
overlying a relatively moist boundary layer east of the dryline,
characterized by lower/middle 60s dewpoints. This is supporting
upwards of 2500 J/kg of MLCAPE. Very isolated instances of
significant severe hail could occur. However, overall storm coverage
may be lacking, owing to the lack of stronger deep ascent.
Regardless, convective and environmental trends will continue to be
monitored.

..Cohen/Hart.. 06/13/2017

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

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

LAT...LON   30650404 32270262 32870191 32780115 32250104 30160249
            29840389 30650404

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 13, 3:14 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 18 more3 hr
Jun 13, 3:38 PM CDTSevere Thunderstorm WatchSPCArmstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 28 more7 hr
Jun 13, 6:30 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 23 more90 min

Nearby

Mesoscale Discussions in Texas, 2017Every mesoscale discussion in 2017

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.