MD 0500 CONCERNING SEVERE THUNDERSTORM WATCH 145… FOR PORTIONS OF NORTHEASTERN KS…SOUTHEASTERN NE…NORTHWESTERN MO…AND IA
Mesoscale Discussion 0500
NWS Storm Prediction Center Norman OK
0722 PM CDT Sat Apr 15 2017
Areas affected...Portions of northeastern KS...southeastern
NE...northwestern MO...and IA
Concerning...Severe Thunderstorm Watch 145...
Valid 160022Z - 160115Z
The severe weather threat for Severe Thunderstorm Watch 145
continues.
SUMMARY...Mainly a large hail and strong to locally damaging wind
threat continues across Severe Thunderstorm Watch 145. The prospect
for a downstream watch into eastern IA remains unclear.
DISCUSSION...Multiple discrete supercells and clusters of convection
producing large hail and occasional strong/damaging winds are
ongoing along and ahead of a surface cold front as of 00Z. The
airmass downstream of this ongoing activity remains weakly to
moderately unstable, with the highest instability generally across
northeastern KS into northwestern MO and southern IA, where MLCAPE
ranges from 1000-2000 J/kg. Instability decreases with eastward
extent into eastern IA per 00Z sounding from DVN (MLCAPE around 250
J/kg), likely due to pre-frontal convection that formed earlier this
afternoon limiting greater diurnal heating/destabilization.
West-southwesterly mid-level winds of 35-45 kt are contributing to
similar effective bulk shear values, and many storms exhibiting
mid-level rotation and updraft organization have produced large hail
over the past several hours. Large hail and damaging winds should
remain the primary threats. A tornado may also be possible where
convection can remain mainly discrete as a southwesterly low-level
jet undergoes modest strengthening this evening, and effective SRH
likewise increases to 200-250 m2/s2 (mainly across southern IA into
northern MO). Across eastern IA, the likelihood for additional watch
issuance remains unclear, as instability remains weak and upstream
convection has not yet grown upscale into a line.
..Gleason.. 04/16/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DVN...ARX...DMX...EAX...OAX...TOP...
LAT...LON 39419709 40749575 41759455 42549340 42809224 42649144
41589125 40569243 39489459 38669689 38889722 39129739
39419709
from SPC Mesoscale Discussions http://bit.ly/1OUXRBK
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