Mesoscale Discussion 572

Issued

May 9, 2021, 3:42 PM CDT (20:42 UTC)

Expired

May 9, 2021, 5:15 PM CDT

In force

93 min

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 157...158

The Little Rock radar (KLZK), 107 km from the middle of the area, began a volume at 20:44 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 161May 9, 7:30 PM CDT

701 
ACUS11 KWNS 092042
SWOMCD
SPC MCD 092042 
MSZ000-TNZ000-MOZ000-ARZ000-LAZ000-TXZ000-092215-

Mesoscale Discussion 0572
NWS Storm Prediction Center Norman OK
0342 PM CDT Sun May 09 2021

Areas affected...ArkLaTex region into the Mid South

Concerning...Severe Thunderstorm Watch 157...158...

Valid 092042Z - 092215Z

The severe weather threat for Severe Thunderstorm Watch 157, 158
continues.

SUMMARY...Thunderstorms are expected to gradually intensify through
the remainder of the afternoon. Large hail, damaging wind, and
perhaps a tornado or two will be possible with the strongest storms.

DISCUSSION...At 2030Z, thunderstorms are increasing in coverage
along a cold front from AR into far northeast TX, with other
stronger prefrontal cells noted across southern AR and northern MS.
Thus far, only gradual intensification has been noted, despite a
favorable environment characterized by MLCAPE of 1500-3000 J/kg and
effective shear of 40-50 kt. The sluggish intensification thus far
may be related to the generally limited large-scale ascent across
the region, and the gradual weakening of low-level flow and
convergence along the front. However, with relatively strong heating
ongoing south of the front from northeast TX into southern AR,
thunderstorms should continue to strengthen, with at least a few
supercells likely to evolve by late afternoon. 

Large hail is expected to remain the primary threat in the short
term, with significant (2 inch diameter or greater) hail still
possible with any supercell that can develop. While low-level
flow/shear is generally weakening with a time, a tornado or two
cannot be ruled out, especially in the vicinity of a remnant outflow
boundary extending from east-central AR into western TN, and where
low-level shear is still relatively strong across northern MS. One
or more clusters may also develop with time, which would pose a
greater risk of damaging wind gusts along their path.

..Dean.. 05/09/2021

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

ATTN...WFO...MEG...JAN...LZK...SHV...

LAT...LON   33469463 33619442 34349352 35169206 35889067 36069004
            35988969 35618892 34978844 34618839 34098851 33828859
            33759040 33159179 32729275 32399323 32229379 32179434
            32369477 32989489 33139486 33469463

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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.