Mesoscale Discussion 1436

Issued

Aug 7, 2021, 6:11 PM CDT (23:11 UTC)

Expired

Aug 7, 2021, 8:15 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 412

The Dodge City radar (KDDC), 123 km from the middle of the area, began a volume at 23:12 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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• Severe Thunderstorm Watch 414Aug 7, 6:35 PM CDT

067 
ACUS11 KWNS 072312
SWOMCD
SPC MCD 072311 
NEZ000-KSZ000-OKZ000-TXZ000-080115-

Mesoscale Discussion 1436
NWS Storm Prediction Center Norman OK
0611 PM CDT Sat Aug 07 2021

Areas affected...Parts of southeastern Nebraska...western and
central Kansas and adjacent portions of the Oklahoma

Concerning...Severe Thunderstorm Watch 412...

Valid 072311Z - 080115Z

The severe weather threat for Severe Thunderstorm Watch 412
continues.

SUMMARY...An eastward advancing corridor of increasingly widespread
thunderstorm development is expected through 7-9 PM CDT, with strong
to locally severe wind gusts becoming an increasing hazard.  Trends
are being monitored for the possibility of one or two additional
severe weather watches.

DISCUSSION...Stronger surface heating and deeper boundary-layer
mixing is focused near the pre-frontal surface trough axis across
the Texas/Oklahoma Panhandle vicinity through the Garden City/Dodge
City areas, into north central Kansas northeast of Hayes and
Russell.  However, the bulk of ongoing thunderstorm development has
been occurring ahead of the cold front through areas west of the
surface trough axis, where higher surface dew points and cooling
aloft ahead an approaching short wave trough area contributing to
greater CAPE (in excess of 1500 J/kg). Beneath 30-40 kt
southwesterly mid-level flow, deep-layer shear is also strong,
contributing to supercell structures north of Garden City.

However, deepening convective development is evident near the
immediate vicinity of the surface trough, and models suggest that a
combination of consolidating convectively generated cold pools and
the cold front will overtake the surface trough during the next few
hours.  Aided by forcing for ascent and cooling aloft associated
with the eastward progressing short wave trough, it appears that
destabilization along the surface trough may support increasingly
widespread thunderstorm development during the next few hours.  By
01-02Z, there is some consensus among the various model output that
this probably will extend from southeast of Dodge City through the
Concordia and Hastings/Grand Island vicinities.

Coinciding with nocturnal southerly low-level jet strengthening
along this corridor (including 30-40+ kt at 850 mb), strong surface
gusts approaching and occasionally exceeding severe limits will
likely become the most prominent severe hazard.

..Kerr.. 08/07/2021

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

ATTN...WFO...OAX...TOP...ICT...OUN...GID...DDC...AMA...

LAT...LON   37570071 39259933 40489874 40859624 39469658 36909913
            36270034 37570071

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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.