Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 373
The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2021, 6:43 PM CDT for 18 counties in Texas. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Apr 12, 2021, 6:43 PM CDT (23:43 UTC)
- Expired
- Apr 12, 2021, 8:15 PM CDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 93
Counties Burnet County, TX, Concho County, TX, Edwards County, TX, Gillespie County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Lampasas County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Real County, TX, San Saba County, TX, Schleicher County, TX, Sutton County, TX, Val Verde County, TX
The radar
The Laughlin AFB radar (KDFX), 120 km from the middle of the area, began a volume at 23:42 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, 11.7 hours before the alert went out and 139 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.
- Mixed-layer CAPE
- 876 J/kg
- Mixed-layer CIN
- -408 J/kg
- Mixed-layer LCL
- 922 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 139 m²/s²
- 0-3 km storm-relative helicity
- 124 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted.
381
ACUS11 KWNS 122344
SWOMCD
SPC MCD 122343
TXZ000-130115-
Mesoscale Discussion 0373
NWS Storm Prediction Center Norman OK
0643 PM CDT Mon Apr 12 2021
Areas affected...portions of southwest into central Texas
Concerning...Severe Thunderstorm Watch 93...
Valid 122343Z - 130115Z
The severe weather threat for Severe Thunderstorm Watch 93
continues.
SUMMARY...The severe threat continues across Severe Thunderstorm
Watch #093. Large hail will be the dominant threat over the next few
hours, with up to 3 inch stones possible with the strongest storms.
DISCUSSION...Convection has recently been able to initiate off of
the near-stationary cold front over the past couple of hours, where
low-level convergence is strongest and where a localized minimum in
MLCINH has been noted. The 20Z DRT observed sounding shows that the
8+ C/km mid-level lapse rates plume has advected far enough east,
over the front to support ample buoyancy above the convective
inhibition layer around 850 mb, with the latest RAP PFCs showing
2000 J/kg MLCAPE in place. While storms have had a history of
becoming supercellular immediately after initiation, with up to 2.75
inch hail observed, the updrafts have tended to dissipate within an
hour of initiation, suggesting that convective inhibition may
constrain the severe threat to storms closest to the front.
Nonetheless, updrafts that continue to develop near the front and
mature will have the tendency to produce large hail, with 2-3 inch
stones likely with the more intense storms. The severe threat is
expected to gradually wane after sunset, as the loss of daytime
heating will reduce the amount of lift near the front.
..Squitieri.. 04/12/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...EWX...SJT...MAF...
LAT...LON 29650195 30960101 31579969 31639865 31289807 30799796
30129863 29559962 29080023 28990088 29650195SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 12, 3:00 PM CDT | Mesoscale Discussion | SPC | Brown, Coleman, Concho, Edwards, Kimble, McCulloch and 7 more | 2 hr |
| Apr 12, 3:51 PM CDT | Severe Thunderstorm Watch | SPC | Burnet, Concho, Edwards, Gillespie, Kimble, Kinney and 8 more | 7 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.