Mesoscale Discussion 548

Issued

Apr 22, 2017, 4:56 PM CDT (21:56 UTC)

Expired

Apr 22, 2017, 6:00 PM CDT

In force

64 min

Issued by

the Storm Prediction Center

The Columbus AFB radar (KGWX), 44 km from the middle of the area, began a volume at 21:59 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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152 
ACUS11 KWNS 222156
SWOMCD
SPC MCD 222156 
TNZ000-GAZ000-ALZ000-MSZ000-LAZ000-222300-

Mesoscale Discussion 0548
NWS Storm Prediction Center Norman OK
0456 PM CDT Sat Apr 22 2017

Areas affected...Central Mississippi...northwestern Alabama...and
southern middle Tennessee

Concerning...Severe Thunderstorm Watch 158...

Valid 222156Z - 222300Z

The severe weather threat for Severe Thunderstorm Watch 158
continues.

SUMMARY...Scattered to numerous storms continue in WW 158, with a
continued threat for hail, damaging wind gusts, and perhaps a
tornado or two through at least 02Z.

DISCUSSION...Scattered thunderstorms have increased in coverage and
intensity over the past couple of hours in WW 158.  These storms
have a history of producing hail, damaging wind gusts, and a tornado
or two.  The highest (albeit low) tornado threat appears to be
concentrated in northern portions of the WW (from northeastern
Mississippi into far southern Middle Tennessee) where a few weakly
rotating supercell structures have evolved despite mostly
unidirectional wind profiles and relatively weak low-level wind
shear.  Farther south into central Mississippi, storms have
congealed into linear segments and tended to propagate
east-southeastward toward the southern edge of WW 158.  

Ongoing trends suggest that far western portions of WW 158 behind
the strongest activity may be cleared soon.  Southward spatial
extensions of the WW across central/east-central Mississippi may be
needed to address the evolving multicellular downburst threat in
that area.  Additional sub-severe storms continue in parishes of
east-central Louisiana, and these may also pose a brief severe
threat as they move eastward into southwestern Mississippi where
moderate instability exists.  Finally, spatial extensions of the
watch will likely be needed in northeastern Alabama downstream of
the watch before scheduled expiration.

..Cook/Guyer.. 04/22/2017

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

ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MEG...JAN...

LAT...LON   32628776 32228862 31828948 31539046 31509135 31589179
            32019171 32849077 33689012 35458798 35718677 35718669
            35708619 35668598 35528561 35488554 35408548 35378548
            35368551 34528558 34028604 32628776

Mesoscale Discussions in Mississippi, 2017Mesoscale Discussions in Alabama, 2017Mesoscale Discussions in Tennessee, 2017Every mesoscale discussion in 2017

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.