Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 1858
The Storm Prediction Center issued this mesoscale discussion at Oct 14, 2021, 3:22 AM CDT for 6 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 14, 2021, 3:22 AM CDT (08:22 UTC)
- Expired
- Oct 14, 2021, 5:45 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Colorado County, TX, DeWitt County, TX, Gonzales County, TX, Guadalupe County, TX, Lavaca County, TX, Wilson County, TX
The radar
The Austin/San Antonio radar (KEWX), 85 km from the middle of the area, began a volume at 08:26 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
Corpus Christi, TX (KCRP), launched 00:00Z, 8.4 hours before the alert went out and 187 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
- 1651 J/kg
- Mixed-layer CIN
- -85 J/kg
- Mixed-layer LCL
- 867 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 97 m²/s²
- 0-3 km storm-relative helicity
- 95 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 7.0
The text
As transmitted.
221
ACUS11 KWNS 140822
SWOMCD
SPC MCD 140822
TXZ000-141045-
Mesoscale Discussion 1858
NWS Storm Prediction Center Norman OK
0322 AM CDT Thu Oct 14 2021
Areas affected...Portions of central/coastal TX
Concerning...Severe potential...Watch unlikely
Valid 140822Z - 141045Z
Probability of Watch Issuance...5 percent
SUMMARY...An isolated severe risk may persist for a couple of hours
early this morning. Watch issuance is not expected.
DISCUSSION...A supercell on the southern flank of a large area of
precipitation has shown recent signs of low-level rotation. Although
a southerly low-level jet across central/coastal TX remains fairly
modest (20-25 kt), there is some enhancement to flow in the 0-1-km
layer. Around 200 m2/s2 of 0-1-km SRH is present per the KCRP VWP,
which is enough for modest storm organization and the low-level
rotation which has been observed. Strong/gusty winds and perhaps a
brief tornado may occur in the short term with the ongoing
supercell. Less clear is the prospect for continued storm
organization early this morning. A weak impulse embedded within the
large-scale upper trough encompassing much of the western and
central CONUS should slowly depart this region as it overspreads the
ArkLaTex and lower MS Valley. The southerly low-level jet is also
forecast to gradually diminish through the morning as well. Given
the lack of stronger large-scale forcing and a marginal
thermodynamic environment, the potential for sustained/organized
severe storms appears relatively low. Accordingly, watch issuance is
not expected early this morning.
..Gleason/Edwards.. 10/14/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 29609796 29559733 29879643 29629618 29349628 29099685
28849775 29199820 29609796SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 13, 7:50 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bexar, Comal, Duval, Frio, Guadalupe and 6 more | 115 min |
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.