Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 1716

September 8, 202110 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2021, 3:51 PM CDT for 10 counties in Texas. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Sep 8, 2021, 3:51 PM CDT (20:51 UTC)
Expired
Sep 8, 2021, 5:45 PM CDT
In force
114 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Concho County, TX, Gillespie County, TX, Kerr County, TX, Kimble County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, San Saba County, TX, Schleicher County, TX

The radar

The San Angelo radar (KSJT), 125 km from the middle of the area, began a volume at 20:52 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 12:00Z, 8.9 hours before the alert went out and 205 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, Del Rio, TX at 12:00Z on 2021-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 993 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, Del Rio, TX at 12:00Z on 2021-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -49 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
993 J/kg
Mixed-layer CIN
-135 J/kg
Mixed-layer LCL
1332 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-49 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

441 
ACUS11 KWNS 082052
SWOMCD
SPC MCD 082051 
TXZ000-082245-

Mesoscale Discussion 1716
NWS Storm Prediction Center Norman OK
0351 PM CDT Wed Sep 08 2021

Areas affected...Parts of the Texas Hill Country

Concerning...Severe potential...Watch unlikely 

Valid 082051Z - 082245Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated strong-severe downburst winds will be possible
late this afternoon/evening, but a watch is not expected.

DISCUSSION...South of a diffuse surface cold front and west of a
subtle trough/moisture gradient, deep mixing and hot surface
temperatures well into the 90s are contributing to moderate buoyancy
and steep low-level lapse rates.  Thunderstorm development appears
probable in the next 1-2 hours in the area of deep mixing, on the
western tail of a weak/remnant MCV from prior convection.  Though
wind profiles will remain weak, a few high-based storms will have
the potential to produce strong-severe outflow winds of 50-60 mph
for a few hours late this afternoon/evening with a loosely organized
cluster of storms that will spread southwestward.

..Thompson/Hart.. 09/08/2021

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

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

LAT...LON   31039844 30649840 30249856 29939890 29879939 30029995
            30340042 30710056 31270048 31550009 31549968 31389905
            31039844

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.