Mesoscale Discussion 156

Issued

Mar 12, 2021, 1:48 PM CST (19:48 UTC)

Expired

Mar 12, 2021, 3:45 PM CST

In force

117 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...tornado watch likely

Chance of a watch

80%

The Lubbock radar (KLBB), 78 km from the middle of the area, began a volume at 19:52 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.

• Tornado Watch 17Mar 12, 3:20 PM CST

137 
ACUS11 KWNS 121949
SWOMCD
SPC MCD 121948 
TXZ000-122145-

Mesoscale Discussion 0156
NWS Storm Prediction Center Norman OK
0148 PM CST Fri Mar 12 2021

Areas affected...portions of the Texas Panhandle and Texas South
Plains vicinity

Concerning...Severe potential...Tornado Watch likely 

Valid 121948Z - 122145Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms are expected to develop by 22z and quickly
become severe across parts of the Texas Panhandle/South Plains
vicinity. A couple of tornadoes, very large hail and damaging gusts
are all possible with these storms. A tornado watch will likely be
needed in the next couple of hours.

DISCUSSION...As of 1930z, a quasi-stationary surface front extended
from just south of the I-40 corridor across the Texas Panhandle,
east/northeast to northeast Oklahoma. South of the boundary, surface
temperatures have warmed into the upper 60s to low 70s across the TX
Panhandle and South Plains vicinity. Skies remain mostly cloudy, but
southerly low level flow has allowed dewpoints to increase around
2-4 degrees F over the past few hours, with values generally in the
mid-to-upper 50s, with some additional increase possible. Atop the
moistening boundary layer, midlevel lapse rates around 7.5-8.5 C/km
are already in place. This is allowing for weak destabilization this
afternoon, with MLCAPE values increasing to around 500 J/kg south of
the surface boundary. Additional warming/moistening this afternoon
should result in additional destabilization and gradually eroding
CINH. 

Strong effective shear greater than 50 kt and steep midlevel lapse
rates will allow storms to quickly organize this afternoon, even in
a weaker instability environment. Low level south/southeasterly flow
in the lowest 1-2 km is not particularly strong, resulting in
somewhat small, but favorably curved, low level hodographs with
20-30 kt 0-3 km shear values. As a result, supercells capable of
producing a couple of tornadoes, especially in the vicinity of the
surface front, will be possible. Potentially significant hail
(greater than 2 inches in diameter) also appears probable given
favorable deep layer flow and long, straight hodographs above low
level curvature. Damaging wind gusts also will be possible with any
discrete supercell, and may become more likely toward evening as
storm mode becomes more linear. 

Additional isolated strong-to-severe storms capable of hail and
possibly strong wind gusts are possible north of the surface front.
These storms will be elevated on the cool side of the boundary. This
threat should remain limited spatially, and the need for a separate
watch is uncertain.

..Leitman/Grams.. 03/12/2021

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

ATTN...WFO...OUN...LUB...AMA...MAF...

LAT...LON   34000006 33590031 33160096 32950177 32940210 32970229
            33080256 33310272 33770280 34120283 34460274 34840251
            35180189 35310129 35340088 35360062 35300046 35090019
            34750004 34500000 34230000 34070006 34000006

Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021

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.