Mesoscale Discussion 2073

Issued

Dec 29, 2021, 1:18 PM CST (19:18 UTC)

Expired

Dec 29, 2021, 2:45 PM CST

In force

87 min

Issued by

the Storm Prediction Center

Concerning

Tornado watch 569

The Columbus AFB radar (KGWX), 164 km from the middle of the area, began a volume at 19:18 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.

957 
ACUS11 KWNS 291918
SWOMCD
SPC MCD 291918 
MSZ000-ARZ000-292045-

Mesoscale Discussion 2073
NWS Storm Prediction Center Norman OK
0118 PM CST Wed Dec 29 2021

Areas affected...extreme southeast AR into northern MS

Concerning...Tornado Watch 569...

Valid 291918Z - 292045Z

The severe weather threat for Tornado Watch 569 continues.

SUMMARY...The severe thunderstorms threat is expected to increase
over the next couple of hours across northern MS.

DISCUSSION...GOES-16 1-minute data, specifically the cloud phase
distinction RGB, has shown vertical development in TCU with
beginnings of glaciation from near the Mississippi River in far
northeast LA into north-central MS over the past 30 minutes. Should
this trend continue and semi-discrete cells develop, a corridor of
greater relative severe threat can be expected over the next 2-3
hours across the MCD area. 

A surface boundary from morning convection extends from near Tunica,
eastward across northern MS. To the south of this boundary,
temperatures have warmed into the upper 70s  with dewpoints in the
upper 60s to near 70 F. This has resulted in rather quick
destabilization with MLCAPE ranging from 500-1500 J/kg. Recent VWP
data from KGWX shows a vertically veering wind profile with a
somewhat small, but favorably curved low-level hodograph. Low-level
shear is forecast to improve somewhat with time, resulting in
slightly larger hodographs and a more favorable environment to
support supercells capable of producing a few tornadoes this
afternoon.

..Leitman.. 12/29/2021

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

ATTN...WFO...MEG...JAN...LZK...

LAT...LON   34479085 34678970 34708901 34618871 34318840 34128844
            33798871 33438921 33208968 33198982 33119008 33089093
            33199124 33349135 33609139 33799133 34129123 34339103
            34479085

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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.