Mesoscale Discussion 197

Issued

Mar 17, 2021, 6:40 AM CDT (11:40 UTC)

Expired

Mar 17, 2021, 8:15 AM CDT

In force

95 min

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 25

The Shreveport radar (KSHV), 130 km from the middle of the area, began a volume at 11:41 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 27Mar 17, 7:45 AM CDT
• Tornado Watch 28Mar 17, 8:40 AM CDT

625 
ACUS11 KWNS 171141
SWOMCD
SPC MCD 171140 
ARZ000-LAZ000-TXZ000-OKZ000-171315-

Mesoscale Discussion 0197
NWS Storm Prediction Center Norman OK
0640 AM CDT Wed Mar 17 2021

Areas affected...Portions of east/northeast TX...eastern
OK...western/central AR...and far northwestern LA

Concerning...Severe Thunderstorm Watch 25...

Valid 171140Z - 171315Z

The severe weather threat for Severe Thunderstorm Watch 25
continues.

SUMMARY...A large hail and damaging wind threat continues across
Severe Thunderstorm Watch 25. A tornado or two also remains
possible. Additional watch issuance or expansion of an existing
watch may be needed in western/central Arkansas as storms approach
this region.

DISCUSSION...A squall line has developed east of the Metroplex in
east-central/northeast TX. Multiple measured wind gusts of 61-73 mph
were reported with this line, along with 1-1.25" diameter hail. A
moderately to strongly unstable airmass (MLCAPE 1500-2500 J/kg)
exists to the east of the ongoing convection in northeast TX and
vicinity. Severe/damaging wind gusts should continue to be the main
threat in the short term given the primarily linear mode and strong
low to mid-level flow present. Isolated, marginally severe hail also
appears possible, but this should be a secondary threat compared to
the severe wind potential. The tornado threat across the ArkLaTex
vicinity should increase later this morning as the boundary layer
destabilizes, and the low/mid-level flow remains quite favorable for
updraft rotation. Still, in the short term, the tornado threat may
be somewhat limited by the linear storm mode. Additional convection
along the OK/AR border has recently developed along an
outflow/bore-like feature. This activity may also pose an isolated
large hail and damaging wind threat if it can strengthen further. At
this point, the need for an additional watch or expansion in area of
an existing watch into western/central AR is unclear, but trends
will be closely monitored.

..Gleason.. 03/17/2021

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

ATTN...WFO...LZK...SHV...TSA...HGX...FWD...OUN...

LAT...LON   31099658 31839595 32939559 34189597 34719557 35409474
            35619431 35589357 35199268 34229242 33369242 32239350
            31089578 30919634 31099658

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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.