Mesoscale Discussion 1994

Issued

Dec 10, 2021, 9:35 PM EST (02:35 UTC)

Expired

Dec 10, 2021, 11:00 PM EST

In force

85 min

Issued by

the Storm Prediction Center

Concerning

Tornado watch 554

The Ft Campbell radar (KHPX), 79 km from the middle of the area, began a volume at 02:38 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.

• Tornado Watch 559Dec 11, 12:00 AM EST

505 
ACUS11 KWNS 110236
SWOMCD
SPC MCD 110235 
KYZ000-INZ000-TNZ000-110400-

Mesoscale Discussion 1994
NWS Storm Prediction Center Norman OK
0835 PM CST Fri Dec 10 2021

Areas affected...portions of western Kentucky

Concerning...Tornado Watch 554...

Valid 110235Z - 110400Z

The severe weather threat for Tornado Watch 554 continues.

SUMMARY...The severe threat continues across Tornado Watch 554, with
a local uptick in tornado potential possible with any discrete
supercells that can become sustained.

DISCUSSION...Multiple supercell structures with transient low-level
rotation have been progressing across northern portions of Tornado
Watch 554 over the past couple of hours. Recently, KHPX radar data
suggests a relatively deep mesocyclone has developed with a
supercell across Muhlenberg County, KY, likely due to increased
low-level shear as the axis of a strong LLJ overspreads the region,
and as richer moisture continues to advect into the region in tandem
with stronger deep-layer ascent. As such, a local uptick in tornado
potential may be realized over the next couple of hours with the
more isolated supercells that persist in the LLJ axis. Also, a
long-lived supercell with a long-tracked, intense tornado is also
approaching Tornado Watch 554, and is expected to approach the
western bounds of the watch in the next couple of hours. Given that
modest instability and strong low-level shear are expected to remain
in place, a potentially significant tornado threat may manifest in
far southwest KY.

..Squitieri/Grams.. 12/11/2021

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

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

LAT...LON   36608840 37148791 37648721 38128648 38318582 38158524
            37728507 37218527 36848552 36608610 36508721 36478771
            36608840

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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.