Mesoscale Discussion 1403

Issued

Jul 31, 2021, 11:00 AM CDT (16:00 UTC)

Expired

Jul 31, 2021, 1:00 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Outlook upgrade

The Paducah radar (KPAH), 179 km from the middle of the area, began a volume at 16:00 UTC, the scan nearest the moment this went out.

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060 
ACUS11 KWNS 311601
SWOMCD
SPC MCD 311600 
KYZ000-ILZ000-TNZ000-MOZ000-ARZ000-311800-

Mesoscale Discussion 1403
NWS Storm Prediction Center Norman OK
1100 AM CDT Sat Jul 31 2021

Areas affected...Southeast MO..Far Northeast AR...Extreme Far
Western KY...Extreme Northwest TN

Concerning...Outlook upgrade 

Valid 311600Z - 311800Z

SUMMARY...Potential severe threat associated with the ongoing
convective line merits an upgrade to Slight Risk in the upcoming
outlook across southeast MO. Trends are also being monitored for
watch issuance.

DISCUSSION...Recent radar and satellite imagery shows a somewhat
steady-state convective line pushing southeastward across southeast
MO at about 35 kt. Surface analysis places this convective line to
north/northeast of a warm front extending from central MO
southeastward into northwest TN. Based on current observations (in
particular the LSX VAD) and modified RAP sounding, updraft bases
within this convective line are likely elevated above the low-level
stable layer. That being said, continued warming and moistening
downstream should result in further reduction of the mixed-layer
convective inhibition. As this occurs, some strengthening of the
ongoing line is possible, although the overall convective evolution
remains uncertain. One negative working against strengthening is the
potential for some convective inhibition to remain, largely as a
result of the warm mid-level temperatures. Conversely, the strong
mid-level flow sampled by the LSX VAD as the system moved through
suggests it may be organized enough to overcome the convective
inhibition and re-intensify amid diurnal heating. 

Despite the uncertainty, the threat this convective line could pose
merits upgrading a portion of southeast MO to Slight Risk in the
upcoming 1630Z. Additionally, trends are being monitored closely for
potential watch issuance.

..Mosier/Grams.. 07/31/2021

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

ATTN...WFO...PAH...MEG...LSX...LZK...SGF...

LAT...LON   37369217 37869156 37909003 37168882 36198876 36159038
            36499244 37369217

Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Kentucky, 2021Mesoscale Discussions in Arkansas, 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.