Mesoscale Discussion 193

Issued

Mar 17, 2021, 4:04 AM CDT (09:04 UTC)

Expired

Mar 17, 2021, 5:30 AM CDT

In force

86 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch likely

Chance of a watch

80%

The Shreveport radar (KSHV), 145 km from the middle of the area, began a volume at 09:04 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.

• Severe Thunderstorm Watch 25Mar 17, 4:35 AM CDT

686 
ACUS11 KWNS 170904
SWOMCD
SPC MCD 170904 
LAZ000-ARZ000-TXZ000-OKZ000-171030-

Mesoscale Discussion 0193
NWS Storm Prediction Center Norman OK
0404 AM CDT Wed Mar 17 2021

Areas affected...Portions of north-central/northeast
TX...southeastern OK...southwestern AR...and far northwestern LA

Concerning...Severe potential...Watch likely 

Valid 170904Z - 171030Z

Probability of Watch Issuance...80 percent

SUMMARY...Another watch downstream of Severe Thunderstorm Watch 23
will likely be needed. Large hail and damaging wind gusts should be
the main threats, but a tornado or two may also occur.

DISCUSSION...Strong to severe storms have organized into a broken
line just west of the Metroplex as of 09Z. Inbound velocities from
the KFWS radar show 50+ kt winds only two to three thousand ft above
the surface. A couple measured severe wind gusts to 60-63 mph also
occurred earlier with this activity. Current expectations are for
storms to maintain their intensity and severe hail/wind threat as
they move east-northeastward this morning, since a moderately to
strongly unstable airmass (2000-2500 J/kg MLCAPE) exists downstream
of the ongoing convection. Both low-level and deep-layer shear will
also remain strong, supporting organized storm structures. A
bore-like feature is noted ahead of the main line of storms. Slight
veering of the low-level flow to a more southwesterly direction
appears to be occurring behind this bore, with some modest reduction
in effective SRH and low-level hodographs. The tornado threat
remains unclear, especially given the mostly linear storm mode
expected. Regardless, there is plentiful low-level shear across the
warm sector owing to a 35-40 kt low-level jet, and a tornado or two
may still occur. Given the overall increase in severe threat
anticipated this morning across north-central/northeast TX into the
southeastern OK, southwestern AR, and far northwestern LA, another
watch will likely be needed.

..Gleason/Thompson.. 03/17/2021

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

ATTN...WFO...SHV...TSA...FWD...OUN...

LAT...LON   31459686 32259646 33239660 33959669 34399600 34279497
            33959384 33659329 33159308 32369363 31759467 31539605
            31459686

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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.