SPC MD 1643

MD 1643 CONCERNING SEVERE THUNDERSTORM WATCH 474... FOR PARTS OF NORTH CENTRAL TEXAS AND ADJACENT PORTIONS OF OKLAHOMA

Mesoscale Discussion 1643
NWS Storm Prediction Center Norman OK
0152 AM CDT Sun Aug 30 2020

Areas affected...Parts of north central Texas and adjacent portions
of Oklahoma

Concerning...Severe Thunderstorm Watch 474...

Valid 300652Z - 300745Z

The severe weather threat for Severe Thunderstorm Watch 474
continues.

SUMMARY...Strong thunderstorms may persist and overspread portions
of north central Texas, including parts of the Dallas-Fort Worth
Metroplex, through 3-5 AM CDT.  This may be accompanied by strong
wind gusts and some hail, but activity, in general, may remain below
severe limits.  A new severe weather watch is not anticipated, but
trends will be monitored.

DISCUSSION...A fairly significant convectively generated/enhanced
surface cold pool is advancing southeast of the Texas
Panhandle/southwest Oklahoma vicinity around 35 kt.  This has
largely been taking place beneath a remnant shallow frontal
inversion layer, and beneath remnants of warm and capping elevated
mixed-layer air.  

However, lift near the nose of stronger rear-inflow evident in radar
imagery appears to be contributing to the maintenance of a small
area of vigorous convective development, above/to the cool side of
the leading edge of the convective outflow.  It appears that
updrafts are still being supported by inflow of moisture emanating
from a boundary layer characterized by lower 70s F surface dew
points.  This is contributing to most unstable CAPE on the order of
2000 J/kg, which could maintain convection several more hours.

Based on objective instability analyses, and possible interaction
with a downstream outflow boundary, this probably will remain
focused south of the Red River, and could impact at least parts of
the Dallas-Fort Worth Metroplex by 09-10Z.  Some of this activity
may pose a risk for hail and strong surface gusts, but this probably
will continue to remain mostly below severe limits.

..Kerr.. 08/30/2020

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

ATTN...WFO...SHV...FWD...OUN...SJT...

LAT...LON   34209788 33629600 32829529 32009585 32429731 32959928
            33279946 33909831 34209788 

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