Mesoscale Discussion 1512

Issued

Aug 13, 2021, 12:24 PM CDT (17:24 UTC)

Expired

Aug 13, 2021, 2:30 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Little Rock radar (KLZK), 58 km from the middle of the area, began a volume at 17:26 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.

430 
ACUS11 KWNS 131724
SWOMCD
SPC MCD 131724 
TNZ000-MOZ000-ARZ000-MSZ000-OKZ000-131930-

Mesoscale Discussion 1512
NWS Storm Prediction Center Norman OK
1224 PM CDT Fri Aug 13 2021

Areas affected...Western Arkansas to Western Tennessee

Concerning...Severe potential...Watch unlikely 

Valid 131724Z - 131930Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms will continue to increase in coverage
through the mid afternoon hours as storms develop within the terrain
of the Ouachita/Ozark mountains and along an outflow boundary.
Isolated wind damage and severe hail is possible, but the organized
severe threat will remain limited.

DISCUSSION...Recent thunderstorm activity noted across AR and
western TN is being driven by a combination of diurnal
heating/orographic ascent and forcing along an outflow boundary from
early-morning convection in southeast MO. Rich boundary-layer
moisture (denoted by dewpoints in the low to mid 70s) is
contributing to moderate to high instability (2000-3000 MLCAPE per
recent RAP mesoanalysis), limited inhibition, and low surface-parcel
convective temperatures. Recent GOES imagery shows numerous
convective towers within the region, suggesting that additional
storms are likely in the coming hours roughly along the I-40
corridor in AR into TN. While IR imagery shows vigorous cloud-top
cooling with some storms, weak deep-layer shear will favor
transient, poorly organized convection and a limited severe threat.
This precludes the need for a watch, though given the ample
instability damaging downburst winds and a few instances of severe
hail will be possible with any stronger storm.

..Moore/Hart.. 08/13/2021

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

ATTN...WFO...MEG...LZK...TSA...

LAT...LON   35539456 35809347 35979164 36088982 36128885 35998831
            35368860 35108916 34949039 34849159 34579274 34379356
            34459434 34789459 35069468 35539456

Mesoscale Discussions in Arkansas, 2021Mesoscale Discussions in Tennessee, 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.