Mesoscale Discussion 1998

Issued

Dec 10, 2021, 9:40 PM CST (03:40 UTC)

Expired

Dec 10, 2021, 11:45 PM CST

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Tornado watch 552...554

The Memphis radar (KNQA), 39 km from the middle of the area, began a volume at 03:41 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 558Dec 10, 10:45 PM CST

664 
ACUS11 KWNS 110341
SWOMCD
SPC MCD 110340 
TNZ000-ALZ000-KYZ000-MSZ000-MOZ000-ARZ000-110545-

Mesoscale Discussion 1998
NWS Storm Prediction Center Norman OK
0940 PM CST Fri Dec 10 2021

Areas affected...portions of southern Arkansas into northwest
Mississippi and western Tennessee

Concerning...Tornado Watch 552...554...

Valid 110340Z - 110545Z

The severe weather threat for Tornado Watch 552, 554 continues.

SUMMARY...The severe threat continues across Tornado Watches 552 and
554. All severe hazards remain a concern and a strong tornado is
possible given the very strong low-level shear in place. Portions of
Tornado Watch 552 will be replaced by a new Tornado Watch by 05Z.

DISCUSSION...Multiple linear segments and embedded supercell
structures persist across southern into eastern AR, with marginally
severe hail reported in southern AR and a TDS recently observed via
KNQA radar data across Craighead Counnty, AR. The latest
mesoanalysis depicts the axis of a strong LLJ roughly along/just
east of the Mississippi River, which continues to transport deep
moisture into the TN Valley, as well as foster impressive low-level
shear. SHV, NQA, and GWX VWPs show relatively long, curved
hodographs with around 300 m2/s2 0-1 km SRH. As such, at least
isolated tornadoes remain possible with the more organized storms,
in addition to damaging gusts and large hail.

At the moment, there is some uncertainty if a locally higher
corridor of tornado potential exists and where. However, current
surface observations across western TN show slightly more backed
winds compared to points farther west/south, with modest pressure
falls noted. As such, the greatest chance for an additional isolated
tornado or two may be across portions of western TN, and a strong
tornado cannot be ruled out.

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

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

ATTN...WFO...OHX...HUN...PAH...MEG...JAN...LZK...

LAT...LON   33989332 35389139 36199021 36498866 36558712 36478703
            36238689 35938702 35588721 35098752 34488840 34129016
            33899140 33749249 33989332

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