Mesoscale Discussion 588

Issued

Apr 29, 2017, 3:39 AM CDT (08:39 UTC)

Expired

Apr 29, 2017, 5:15 AM CDT

In force

96 min

Issued by

the Storm Prediction Center

The Springfield radar (KSGF), 97 km from the middle of the area, began a volume at 08:41 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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252 
ACUS11 KWNS 290839
SWOMCD
SPC MCD 290839 
INZ000-KYZ000-ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-291015-

Mesoscale Discussion 0588
NWS Storm Prediction Center Norman OK
0339 AM CDT Sat Apr 29 2017

Areas affected...Eastern Oklahoma...northwest Arkansas...southern
Missouri...and far southern Illinois

Concerning...Severe Thunderstorm Watch 172...

Valid 290839Z - 291015Z

The severe weather threat for Severe Thunderstorm Watch 172
continues.

SUMMARY...Severe storms persist across WW 172 during the overnight. 
Trends in radar imagery and recent HRRR suggest the severe-weather
threat will persist from northeast OK through southern MO to far
southern IL.  Local WFO temporal extension of WW 172 may be needed
beyond 10Z.  Meanwhile, counties south of these areas within 172
(east-central OK and much of AR) should have a continued lull in
storm potential and may be removed early from this watch.

DISCUSSION...08Z surface analysis showed a boundary extending
eastward from central OK (just south of CHK and OUN) to west-central
AR (near FSM), then northeast through north-central AR into the MO
Bootheel and PAH eastward through northern KY.  Trends in mosaic
radar imagery indicated ongoing strong to severe storms extending
from far northeast OK and far northwest AR into south-central MO,
with additional strong to severe storms in far southern IL. 
Meanwhile, strong to severe storms moving through central OK will
move into northeast OK (western extent of 172) by 09Z maintaining
the valid portion of this watch. 

A 50-60 kt south-southwesterly low-level jet extending from
northwest LA into AR, maintaining strong warm air advection and
isentropic ascent north of the surface boundary, will continue to
support additional storm development into early Saturday morning. 
MUCAPE of 2000-3000 J/kg and effective bulk shear exceeding 50 kt
extending from northeast OK through southern MO to southern IL will
allow for additional organized storms producing large hail and
strong wind gusts.

..Peters/Guyer.. 04/29/2017

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

ATTN...WFO...PAH...LSX...LZK...SGF...TSA...

LAT...LON   36479219 35969384 35579495 35399628 35549654 36129655
            36559588 36969489 37309360 37549259 37789144 37869011
            38168884 38228795 37498815 37138857 37078993 36589158
            36479219

Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Oklahoma, 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.