Mesoscale Discussion 1449

Issued

Aug 5, 2017, 3:25 PM CDT (20:25 UTC)

Expired

Aug 5, 2017, 5:30 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Chance of a watch

40%

The Vance AFB radar (KVNX), 41 km from the middle of the area, began a volume at 20:25 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.

• Severe Thunderstorm Watch 440Aug 5, 4:05 PM CDT
• Severe Thunderstorm Watch 441Aug 5, 7:05 PM CDT

604 
ACUS11 KWNS 052025
SWOMCD
SPC MCD 052025 
MOZ000-OKZ000-KSZ000-TXZ000-052230-

Mesoscale Discussion 1449
NWS Storm Prediction Center Norman OK
0325 PM CDT Sat Aug 05 2017

Areas affected...Much of the central Plains

Concerning...Severe potential...Watch possible 

Valid 052025Z - 052230Z

Probability of Watch Issuance...40 percent

SUMMARY...Storms may begin initiating across parts of the central
Plains during the next few hours.  This probably will be accompanied
by at least some increase in severe weather potential.  Although
this may remain somewhat isolated in nature into early evening, it
is possible that a watch could eventually become necessary.

DISCUSSION...A moderate southwesterly low-level jet (30-40 kt at 850
mb) persists across much of the lower central Plains.  Strongest
near surface convergence appears focused across central Kansas,
roughly between Great Bend and Salina, east of an area of low
pressure centered over southwest Kansas, and near/to the cool side
of a zone of strong differential heating on the western flank of a
convectively reinforced boundary.  This appears largely beneath
substantive mid-level capping associated with a plume of warm
elevated mixed layer which has advected east southeast of the
Wyoming/Colorado Rockies.  The nose of this elevated mixed layer
remains stalled to the southwest of the lower/mid Missouri Valley,
as an associated zone of stronger lower/mid tropospheric warm
advection maintains renewed convective development across and
southeast of the Kansas City metro area.

This capping is contributing to uncertain convective potential into
and through the late afternoon hours.  It seems at least possible
that continued insolation near the stronger low-level forcing for
ascent could eventually contribute to sufficient weakening of
inhibition to support the initiation of boundary layer based
thunderstorms across central Kansas.  This might not be until after
22-23Z, but if/when activity initiates, the environment appears
conducive to the development of supercells, as CAPE becomes
moderately large in the presence of strong vertical shear.

Otherwise, latest visible imagery supports the latest high
resolution Rapid Refresh, among other model output, suggesting that
convective temperatures may be reached within the hot and deeply
mixed boundary layer to the southeast of the surface low center
within the next couple of hours.  This may lead to the initiation of
scattered vigorous thunderstorm activity across parts of the Texas
Panhandle region through western Oklahoma and adjacent portions of
south central Kansas, where the main severe risk appears to be
locally strong surface gusts.

..Kerr/Dial.. 08/05/2017

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

ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...GID...DDC...
SJT...GLD...LUB...AMA...

LAT...LON   38660036 39449780 39119554 38149423 36569461 35659725
            34699848 33299998 33390145 34820178 36630065 38660036

Mesoscale Discussions in Kansas, 2017Mesoscale Discussions in Oklahoma, 2017Mesoscale Discussions in Texas, 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.