Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 285
The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2021, 4:34 PM CDT for 15 counties in Texas. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- Mar 27, 2021, 4:34 PM CDT (21:34 UTC)
- Expired
- Mar 27, 2021, 6:30 PM CDT
- In force
- 116 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
Counties Anderson County, TX, Brazos County, TX, Freestone County, TX, Henderson County, TX, Hopkins County, TX, Houston County, TX, Kaufman County, TX, Leon County, TX, Madison County, TX, Rains County, TX, Robertson County, TX, Smith County, TX, Trinity County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 149 km from the middle of the area, began a volume at 21:35 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
Fort Worth, TX (KFWD), launched 12:00Z, 9.6 hours before the alert went out and 162 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
- 1088 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 40 m²/s²
- 0-3 km storm-relative helicity
- 21 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted.
135
ACUS11 KWNS 272135
SWOMCD
SPC MCD 272134
TXZ000-272330-
Mesoscale Discussion 0285
NWS Storm Prediction Center Norman OK
0434 PM CDT Sat Mar 27 2021
Areas affected...parts of east Texas
Concerning...Severe potential...Watch possible
Valid 272134Z - 272330Z
Probability of Watch Issuance...60 percent
SUMMARY...Storms are expected to form into east Texas over the next
few hours, with primarily a damaging hail threat. A brief tornado is
also possible.
DISCUSSION...Strong instability has developed over the region, with
MLCAPE in excess of 2000 J/kg beneath strong southwesterlies aloft.
This area is well ahead of the cold front, currently over southern
OK into northwest TX. Only minor capping exists near 700 mb, and it
is expected that the convection developing northwest of Houston will
continue to deepen and eventually become severe southeast of the
Metroplex. Low-level winds and shear are a bit marginal for a
tornado threat, but supercell storm mode may favor a brief tornado
given strong updrafts. Hodographs are quite elongated, and will
support supercell storm mode favoring large, damaging hail this
evening after 23-00Z.
..Jewell/Grams.. 03/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SHV...HGX...FWD...
LAT...LON 32199644 32689631 33049611 33199580 33179522 32939512
31779518 31489487 31169485 30419647 30699672 31479654
32199644SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 27, 2:16 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Cherokee, Gregg, Harrison and 9 more | 89 min |
| Mar 27, 3:25 PM CDT | Tornado Watch | SPC | Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 11 more | 10 hr |
| Mar 27, 6:42 PM CDT | Mesoscale Discussion | SPC | Bowie, Cass, Cherokee, Gregg, Harrison, Marion and 4 more | 2 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.