Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 689

May 19, 202112 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 19, 2021, 6:06 PM CDT for 12 counties in Texas. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
May 19, 2021, 6:06 PM CDT (23:06 UTC)
Expired
May 19, 2021, 7:30 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Crane County, TX, Crockett County, TX, Ector County, TX, Glasscock County, TX, Irion County, TX, Midland County, TX, Reagan County, TX, Schleicher County, TX, Sterling County, TX, Sutton County, TX, Tom Green County, TX, Upton County, TX

The radar

The Midland/Odessa radar (KMAF), 79 km from the middle of the area, began a volume at 23:07 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, 11.1 hours before the alert went out and 81 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 2021-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1241 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 2021-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 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
1241 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
649 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
254 m²/s²
Significant tornado parameter
1.0
Supercell composite
9.6

Open this sounding in Storm Lab

The text

As transmitted.

081 
ACUS11 KWNS 192307
SWOMCD
SPC MCD 192306 
TXZ000-200030-

Mesoscale Discussion 0689
NWS Storm Prediction Center Norman OK
0606 PM CDT Wed May 19 2021

Areas affected...West Texas

Concerning...Severe potential...Watch unlikely 

Valid 192306Z - 200030Z

Probability of Watch Issuance...5 percent

SUMMARY...Thunderstorms posing a threat for large hail will persist
for the next couple of hours before diminishing later this evening.

DISCUSSION...Thunderstorms are ongoing across far west Texas this
evening posing a risk of large hail. One such thunderstorm is
currently moving southeast into the greater Midland area and another
moving northeast into Crockett county. These thunderstorms continue
within an environment best characterized as weakly capped and
sufficiently unstable. Deep-layer shear is marginally supportive of
thunderstorm organization, with decreasing support farther east.
Absent strongly deep-layer shear, the intensity of these storms
should wane with time this evening as the boundary layer cools and
instability decreases. One potential exception to this will be when
the westward-moving outflow boundary across Crockett, Irion, and
Sterling counties interacts with the eastward moving storms
currently located from Pecos county northward into Midland county.
Should these storm-scale interactions occur, increased low-level
convergence may result in a brief increase in updraft strength and
an increased hail potential. However, the relatively localized space
and time nature of the threat should preclude the need for a watch.

..Marsh/Dial.. 05/19/2021

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

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

LAT...LON   31970267 32330230 32240109 31480046 30600029 30180114
            30310206 31240254 31970267

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 18, 7:34 PM CDTTornado WatchSPCAustin, Bee, Brazoria, Chambers, Colorado, Fort Bend and 17 more6 hr
May 18, 8:00 PM CDTMesoscale DiscussionSPCCherokee, Gregg, Harrison, Marion, Nacogdoches, Panola and 4 more60 min
May 18, 8:54 PM CDTMesoscale DiscussionSPCAustin, Fort Bend, Harris, Jackson, Montgomery, Waller and 1 more96 min
May 18, 10:39 PM CDTMesoscale DiscussionSPCHardin, Jasper, Jefferson, Newton, Orange, Tyler96 min
May 18, 11:00 PM CDTMesoscale DiscussionSPCDimmit, Duval, Jim Hogg, La Salle, Webb, Zapata90 min
May 19, 3:32 AM CDTMesoscale DiscussionSPCBrooks, Dimmit, Duval, Hidalgo, Jim Hogg, Jim Wells and 5 more118 min
May 19, 5:24 AM CDTSevere Thunderstorm WatchSPCBrooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 8 more8 hr
May 19, 7:09 AM CDTMesoscale DiscussionSPCHidalgo, Jim Hogg, Starr96 min
May 19, 8:46 AM CDTMesoscale DiscussionSPCBrooks, Cameron, Hidalgo, Kenedy, Willacy89 min
May 19, 2:10 PM CDTMesoscale DiscussionSPCCallahan, Coke, Coleman, Concho, Crane, Crockett and 24 more3 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.