Mesoscale Discussion 774

Issued

May 27, 2021, 5:21 PM CDT (22:21 UTC)

Expired

May 27, 2021, 7:15 PM CDT

In force

114 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Paducah radar (KPAH), 42 km from the middle of the area, began a volume at 22:23 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.

934 
ACUS11 KWNS 272222
SWOMCD
SPC MCD 272221 
KYZ000-INZ000-TNZ000-ILZ000-MOZ000-ARZ000-280015-

Mesoscale Discussion 0774
NWS Storm Prediction Center Norman OK
0521 PM CDT Thu May 27 2021

Areas affected...parts of northeast Arkansas...western
Tennessee...southeast Missouri...southern Illinois...southwest
Indiana...western Kentucky

Concerning...Severe potential...Watch unlikely 

Valid 272221Z - 280015Z

Probability of Watch Issuance...20 percent

SUMMARY...An increase in thunderstorm coverage is expected as a line
of storms approaches from the west. While a couple of damaging gusts
and perhaps marginally severe hail may accompany some of the
stronger storms, the severe threat is expect to remain sparse enough
to withhold a WW issuance at this time.

DISCUSSION...A relatively organized squall line is in progress
across parts of southern IL into northeast AR as shown by the latest
MRMS mosaic radar data. While portions of the squall have shown well
developed structures over the past couple of hours (i.e. 30 dBZ echo
tops exceeding 40 kft), the storms are approaching a less
unstable/sheared airmass, characterized by 500-1000 J/kg MLCAPE and
effective bulk shear mainly under 35 kts. While the present
CAPE/shear parameter space supports sustenance of the approaching
MCS with some gusty wind/hail potential, the overall coverage of
severe gusts/hail is expected to remain too sparse in coverage and
intensity to warrant the issuance of a WW at this time.

..Squitieri/Edwards.. 05/27/2021

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

ATTN...WFO...LMK...OHX...IND...PAH...MEG...LZK...

LAT...LON   35819098 36579061 37458960 37948886 38618747 38748660
            38528598 37988572 37388606 36858666 36438742 35978818
            35468887 35328953 35259026 35819098

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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.