SPC MD 653


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Mesoscale Discussion 0653
NWS Storm Prediction Center Norman OK
0545 PM CDT Fri May 17 2019

Areas affected...Northwest Kansas...Portions of Western/Central

Concerning...Tornado Watch 172...

Valid 172245Z - 180045Z

The severe weather threat for Tornado Watch 172 continues.

SUMMARY...The threat for tornadoes and large hail will continue in
Tornado Watch 172. Discrete storms moving out of northwest Kansas
into western/central Nebraska will likely pose the greatest threat
for tornadoes as the low-level flow increases ahead of them.

DISCUSSION...In the wake of mid-level convection dewpoints ahead of
a discrete supercell moving out of northwest Kansas have increased
to the low to mid 60s. Strong pressure falls in the vicinity of the
surface boundary have caused low-level winds to back to SSE.
Regional VAD wind profiles have shown generally straight hodographs
which has led to observed storm splits and a few instances of
destructive interference. A 21Z NSSL research sounding near LBF
showed weak capping and some weak winds within the 850-700 mb layer,
likely due to the passing elevated convection. With time, the
low-level jet is forecast to increase across north-central Kansas
and into portions of central Nebraska. This will aid in low-level
moisture transport and an increase in low-level hodograph curvature
with time. Any discrete storm within this environment will be
capable of strong low-level rotation and a risk for tornadoes. Large
hail will also remain a threat with mid-level lapse rates of 8.5-9
C/km and around 50 kts of effective shear.

The current thinking is that the greatest threat for tornadoes will
come from storms moving into Nebraska from northwest Kansas. Farther
north, nearer the boundary, storms that have formed have generally
moved north of the front.

..Wendt.. 05/17/2019

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


LAT...LON   38270204 39590207 39570272 40450274 40430201 41040204
            41030260 42060270 42089974 42759970 42899892 42739833
            41419833 41399876 40709879 40619920 40069920 39989966
            39159963 39130011 38700021 38700109 38260112 38270204 

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