Mesoscale Discussion 856

Issued

Jun 24, 2018, 7:37 AM CDT (12:37 UTC)

Expired

Jun 24, 2018, 9:30 AM CDT

In force

113 min

Issued by

the Storm Prediction Center

The Little Rock radar (KLZK), 71 km from the middle of the area, began a volume at 12:39 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.

790 
ACUS11 KWNS 241238
SWOMCD
SPC MCD 241237 
TNZ000-MSZ000-ARZ000-TXZ000-OKZ000-241430-

Mesoscale Discussion 0856
NWS Storm Prediction Center Norman OK
0737 AM CDT Sun Jun 24 2018

Areas affected...extreme northeast Texas...much of
Arkansas...northwest Mississippi...and far western Tennessee

Concerning...Severe Thunderstorm Watch 211...

Valid 241237Z - 241430Z

The severe weather threat for Severe Thunderstorm Watch 211
continues.

SUMMARY...Thunderstorms ongoing across western Arkansas will
continue to pose a risk for large hail and strong, gusty winds as
they move into central Arkansas. The environment ahead of this
thunderstorm cluster suggests that a new Severe Thunderstorm Watch
may be needed east of the current watch.

DISCUSSION...Long-lived mesoscale convective system (MCS) with
leading edge bow-echo continues across western Arkansas. Recent
radar trends suggest an uptick in intensity as the MCS is moving
into central Arkansas. Surface dewpoints in the 70s and diurnal
heating will allow for continued destabilization ahead of this
feature. Thus, most-unstable CAPE values currently around 2000 J/kg
should only increase through the morning. Additionally, this area is
on the southern fringe of the better deep-layer shear, which will
only act to further thunderstorm organization and MCS maintenance.
Thus, the severe threat may continue through the morning and begin
to impact areas outside of Severe Thunderstorm Watch 211. The region
will continue to be monitored for the potential of an additional
Severe Thunderstorm Watch to the east of watch 211.

..Marsh/Guyer.. 06/24/2018

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

ATTN...WFO...MEG...JAN...LZK...SHV...TSA...FWD...

LAT...LON   33509557 35709417 36099164 34938954 33099090 33509557

Mesoscale Discussions in Arkansas, 2018Mesoscale Discussions in Mississippi, 2018Mesoscale Discussions in Texas, 2018Every mesoscale discussion in 2018

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.