SPC MD 239


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Mesoscale Discussion 0239
NWS Storm Prediction Center Norman OK
0206 PM CDT Fri Apr 13 2018

Areas affected...Eastern Kansas...Northwest Missouri...Far Southeast
Nebraska...Southern Iowa

Concerning...Severe potential...Watch likely 

Valid 131906Z - 132130Z

Probability of Watch Issuance...80 percent

SUMMARY...A severe threat is likely to develop across northeast
Kansas, northwest Missouri and southern Iowa over the next couple of
hours. Large hail and wind damage will be the initial threat but a
tornado threat is expected to eventually develop. Weather watch
issuance will likely be needed across the region this afternoon.

DISCUSSION...The latest surface analysis shows a 991 mb low over far
southeast Nebraska with a cold front extending south-southwestward
from the low into northeast and central Kansas. A dryline begins
near the front in eastern Kansas and extends southward into northern
Oklahoma. Thunderstorms are developing along the dryline in
southeast Kansas with other cells initiating to the north of the low
in the Omaha area. This convection is expected to increase in
coverage as the cap weakens over the next hour or so. The storms
should reach northwest Missouri and southwest Iowa by mid afternoon.

Ahead of the storms, a corridor of low-level moisture is analyzed
from far southeast Kansas northward into far northwest Missouri
where surface dewpoints are in the lower to mid 60s F. The RAP is
showing MLCAPE values from eastern Kansas into far southwest Iowa in
the 2000 to 2500 J/kg range. In addition, forecast soundings
steadily increase deep-layer shear along the instability corridor
through late this afternoon. 0-6 km shear should reach the 40 to 50
kt range which will be favorable for supercell development. The
instability, shear and steep mid-level lapse rates will be support
large hail formation with the stronger updrafts. Damaging wind gusts
will also be likely as storm organize. As deep-layer shear and
low-level shear increase later this afternoon, a tornado threat will
also likely develop.

..Broyles/Hart.. 04/13/2018

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


LAT...LON   37869651 38009477 39089392 40369332 41209342 41469430
            41549544 41159619 40559642 39759647 38359705 37869651 

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