Mesoscale Discussion 1663

Issued

Jul 21, 2023, 9:43 AM CDT (14:43 UTC)

Expired

Jul 21, 2023, 11:45 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 533

The Little Rock radar (KLZK), 47 km from the middle of the area, began a volume at 14:43 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.

270 
ACUS11 KWNS 211443
SWOMCD
SPC MCD 211443 
ARZ000-211645-

Mesoscale Discussion 1663
NWS Storm Prediction Center Norman OK
0943 AM CDT Fri Jul 21 2023

Areas affected...Parts of AR

Concerning...Severe Thunderstorm Watch 533...

Valid 211443Z - 211645Z

The severe weather threat for Severe Thunderstorm Watch 533
continues.

SUMMARY...Some threat for isolated damaging wind may continue
through the morning, though the need for additional watches in the
short term is uncertain.

DISCUSSION...A line of thunderstorms is moving across northwest AR
at 1430 UTC, in advance of a well-defined MCV moving across
northeast OK. While this convection has largely maintained its
intensity over the last 1-2 hours, there has been little indication
of recent severe gusts. The downstream environment into
north-central AR is currently less unstable, but some diurnal
heating/destabilization may allow the line to continue eastward
through the morning, with some potential for isolated damaging wind.
Unless there is an uptick in organization/intensity over the next
15-30 minutes, WW 533 may be allowed to expire at 15 UTC. 

Farther south, a couple of stronger storm clusters have flared up
across west-central AR; one that is now moving southeast of Little
Rock, and another on the southern periphery of the northern line, to
the west of Little Rock. MLCAPE in excess of 3000 J/kg was observed
on the 12Z LZK sounding, and these storm clusters will tend to
propagate southeastward into a similarly unstable environment, with
some continued heating/destabilization possible downstream.
Deep-layer shear is not particularly strong, but the favorable
thermodynamic environment may support some damaging wind threat
spreading into south-central/southeast AR with time. Coverage of the
severe threat remains uncertain in this area, but watch issuance is
possible if a further uptick in storm coverage/intensity is
observed.

..Dean/Hart.. 07/21/2023

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

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

LAT...LON   36259380 36289258 35609157 34989122 34279095 33589136
            33589272 34309377 34919386 35859385 36259380

Mesoscale Discussions in Arkansas, 2023Every mesoscale discussion in 2023

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.