Mesoscale Discussion 456

Issued

Apr 28, 2021, 5:25 PM CDT (22:25 UTC)

Expired

Apr 28, 2021, 7:30 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 118

The Paducah radar (KPAH), 55 km from the middle of the area, began a volume at 22:24 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.

656 
ACUS11 KWNS 282225
SWOMCD
SPC MCD 282225 
KYZ000-TNZ000-ILZ000-MOZ000-290030-

Mesoscale Discussion 0456
NWS Storm Prediction Center Norman OK
0525 PM CDT Wed Apr 28 2021

Areas affected...Western Kentucky and extreme northwest Tennessee

Concerning...Severe Thunderstorm Watch 118...

Valid 282225Z - 290030Z

The severe weather threat for Severe Thunderstorm Watch 118
continues.

SUMMARY...Severe wind and hail remain possible with a cluster of
storms moving across far western Kentucky and portions of extreme
northwest Tennessee.

DISCUSSION...A linear cluster of storms continues to slowly push
eastward towards the Paducah, KY area. Although KPAH velocity data
suggests a loosely organized cold pool has developed, IR imagery and
MRMS echo top trends reveal robust individual updrafts embedded
within the line. These pulses have been, and will continue to be,
most common along the southern flank of the line along the TN/KY
border where a weak baroclinic zone/instability gradient is located.
The expectation is that this cluster of storms will continue to move
eastward in the coming hours, and stronger updraft pulses along the
southern half of the line will pose a severe hail threat. KPAH
recently sampled nearly 40 knots of 0-3 km bulk shear ahead of the
line, suggesting that further organization of the cold pool (and an
increasing damaging wind threat) is possible. However, this will
likely be dependent on more balanced intensification along the
entire line. Regardless, an isolated wind threat will persist with
any stronger updraft pulses. Although the tornado potential
generally appears low, 150 m2/s2 0-1 km SRH (sampled by KPAH)
indicates that a tornado or two remain possible - especially on the
southern flank along the baroclinic zone where surface winds are
slightly more backed.

..Moore.. 04/28/2021

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

ATTN...WFO...LMK...OHX...PAH...MEG...

LAT...LON   36308967 37108928 37438878 37648802 37638711 37188681
            36728692 36338724 36208789 36108872 36158942 36308967

Mesoscale Discussions in Kentucky, 2021Mesoscale Discussions in Tennessee, 2021Mesoscale Discussions in Illinois, 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.