Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 12
The Storm Prediction Center issued this mesoscale discussion at Jan 6, 2021, 11:56 AM CST for 14 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jan 6, 2021, 11:56 AM CST (17:56 UTC)
- Expired
- Jan 6, 2021, 2:00 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
Counties Bastrop County, TX, Brazos County, TX, Burleson County, TX, Falls County, TX, Fayette County, TX, Grimes County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, Milam County, TX, Robertson County, TX, Travis County, TX, Washington County, TX
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Fort Worth, TX (KFWD), launched 12:00Z, 5.9 hours before the alert went out and 244 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 623 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 314 m²/s²
- 0-3 km storm-relative helicity
- 313 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
836
ACUS11 KWNS 061757
SWOMCD
SPC MCD 061756
TXZ000-062000-
Mesoscale Discussion 0012
NWS Storm Prediction Center Norman OK
1156 AM CST Wed Jan 06 2021
Areas affected...east-central TX
Concerning...Severe potential...Watch possible
Valid 061756Z - 062000Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorms will likely intensify the next few hours. A
severe threat will probably ensue and isolated damaging gusts and
perhaps a tornado risk will accompany the strongest storms.
DISCUSSION...Radar mosaic shows an intensifying thunderstorm over
Milam County, TX to the east of a cold front pushing east across
central TX. The Milam County storm has developed within a zone of
warm air advection ahead of the cold front. Water-vapor imagery
shows a potent mid-level trough over the southern Great Plains
approaching east-central and southeast TX. Forcing for ascent will
continue to increase in response to this feature and modest heating
will continue to slowly destabilize the warm sector over southeast
TX. Additional storms are likely to develop through the early
afternoon near and east of the I-35 corridor and spread eastward
towards the I-45 corridor. Isolated damaging gusts, marginally
severe hail, and perhaps a tornado will be the severe hazards
accompanying the strongest storms.
..Smith/Hart.. 01/06/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HGX...FWD...EWX...
LAT...LON 29949777 30339781 31699667 31689621 31319559 30699562
29809702 29949777SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 6, 12:59 PM CST | Severe Thunderstorm Watch | SPC | Austin, Bastrop, Brazoria, Brazos, Burleson, Chambers and 24 more | 7 hr |
| Jan 6, 5:09 PM CST | Mesoscale Discussion | SPC | Brazoria, Chambers, Galveston | 96 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.