Mesoscale Discussion 607

Issued

Apr 30, 2017, 2:58 AM CDT (07:58 UTC)

Expired

Apr 30, 2017, 4:30 AM CDT

In force

92 min

Issued by

the Storm Prediction Center

The Memphis radar (KNQA), 48 km from the middle of the area, began a volume at 07:57 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.

106 
ACUS11 KWNS 300759
SWOMCD
SPC MCD 300758 
TNZ000-KYZ000-ILZ000-MSZ000-MOZ000-ARZ000-300930-

Mesoscale Discussion 0607
NWS Storm Prediction Center Norman OK
0258 AM CDT Sun Apr 30 2017

Areas affected...Eastern AR...far southeast MO...far northwest
MS...western TN...western KY

Concerning...Severe Thunderstorm Watch 179...

Valid 300758Z - 300930Z

The severe weather threat for Severe Thunderstorm Watch 179
continues.

SUMMARY...Severe weather risk including damaging winds and a tornado
threat continues across WW 179, and will spread east into more of
western TN and southwest KY in the short term, resulting in local
WFO spatial expansion of this watch.  A new watch is not warranted
farther east into the middle part of TN or central KY, given a more
stable environment with eastward extent.

DISCUSSION...Trends in early overnight surface analyses indicated a
well-defined pressure fall/rise couplet (-3 to -4 mb/2 hr and 2-4
mb/2 hr, respectively) attendant to the bowing line of storms moving
through far southeast MO and far northeast AR into western
TN/southwest KY.  This bowing line is moving to the east-northeast
at 50 kt through the northern extent of a corridor of moderate
instability.  This combined with strong bulk shear will continue to
favor a threat for damaging winds as this bow moves into western TN
and southwest KY through 09Z.

The tornado threat should be primarily confined to the vicinity of
an old outflow boundary which extended from the MO Bootheel along
the northwest TN/southwest KY border into the rest of far southwest
KY (north of HOP), then northeast into extreme south-central and
southeast IN (north of FTK and SDF).  Strong low-level shear in
vicinity of this boundary (35-50 kt) and surface vorticity suggest a
continued potential for storms to attain a tornado threat.

..Peters/Guyer.. 04/30/2017

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

ATTN...WFO...OHX...PAH...MEG...

LAT...LON   34869102 35539088 35909031 36599029 37019042 37118931
            37088857 36978788 36878757 36158774 35388852 34978890
            34678962 34569019 34249094 34779097 34869102

Mesoscale Discussions in Tennessee, 2017Mesoscale Discussions in Kentucky, 2017Mesoscale Discussions in Arkansas, 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.