SPC MD 1146

MD 1146 CONCERNING SEVERE THUNDERSTORM WATCH 345... FOR SOUTHWEST INTO NORTH-CENTRAL NE

Mesoscale Discussion 1146
NWS Storm Prediction Center Norman OK
0732 PM CDT Wed Jul 08 2020

Areas affected...southwest into north-central NE

Concerning...Severe Thunderstorm Watch 345...

Valid 090032Z - 090130Z

The severe weather threat for Severe Thunderstorm Watch 345
continues.

SUMMARY...The propensity for severe gusts (60-80 mph) will gradually
increase this evening as upscale growth occurs.

DISCUSSION...Visible-satellite imagery shows several thunderstorm
clusters over NE early this evening.  The cluster over southwest NE
preferentially developed near a north-south dryline/lee trough with
the cluster near the Cherry County vicinity near a frontal zone. 
KUEX shows modest low-level southerly flow whereas KLNX, in closer
proximity to the storms, shows intensification of low-level flow
(+15 to 20 kt at 1km AGL) in the past hour.  Model guidance this
evening shows a strengthening southerly LLJ over the central Great
Plains which should favor upscale growth into one or more clusters
eventually evolving into an MCS.  The 7pm North Platte observed
sounding showed a surface-400mb lapse rate in excess of 8 deg C/km. 
As additional storms develop, mature, and coalesce their cold pools,
considerable evaporative cooling with the stronger downdrafts will
lead to an increased risk for severe gusts and potentially gusts in
the 70-80 mph range.

..Smith.. 07/09/2020

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

ATTN...WFO...LBF...BOU...

LAT...LON   40470197 41190211 42660050 42989914 42609855 42109880
            40940083 40390123 40470197 

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