MD 0409 CONCERNING SEVERE POTENTIAL…SEVERE THUNDERSTORM WATCH LIKELY FOR PORTIONS OF WESTERN AND NORTHERN MISSOURI AND EASTERN KANSAS
Mesoscale Discussion 0409 NWS Storm Prediction Center Norman OK 1254 PM CDT Mon May 14 2018 Areas affected...Portions of western and northern Missouri and eastern Kansas Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 141754Z - 141930Z Probability of Watch Issuance...95 percent SUMMARY...Thunderstorms are expected to develop along and south of a quasi-stationary front between 18 and 19z. Severe wind gusts and marginally severe hail are the main threats. Watch issuance is likely. DISCUSSION...Quickly-eroding convective inhibition, a weak frontal wave/MCV over the Kansas City area, and frontal convergence over Kansas is expected to contribute to scattered thunderstorm development in the next hour or two. Over Missouri, effective bulk wind shear is rather small and will gradually decrease even further through the afternoon to values of 15-25 kt. Effective bulk shear will be slightly higher --25-35 kt-- over eastern Kansas. Multicells will be the dominant mode, but MLCAPE of 2000-2500 J/kg and DCAPE that is expected to rise to 1000-1200 J/kg will contribute to severe wind potential in any of the stronger downdrafts, particularly with the initial thunderstorms before outflow spreads rapidly over the area. Over Missouri, although severe hail is possible in any of the stronger storms, a relative minimum in mid-level lapse rates and a lack of organized storm rotation should keep hail sizes on the marginally-severe end. Over Kansas slightly higher effective bulk shear and larger lapse rates could produce somewhat larger hail over the area. High-resolution guidance suggests outflow will quickly consolidate into a mesoscale cold pool over both areas, but weak vertical wind shear should preclude any organized MCS development and thus preclude any organized, larger-scale severe wind potential. But the coverage of storms and severe wind/hail potential is expected to be large enough to need a Severe Thunderstorm Watch over the area by 19z. ..Coniglio/Grams.. 05/14/2018 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...DVN...SGF...EAX...TOP...ICT... LAT...LON 38179223 38079283 37819481 37479671 37449729 37769748 38269704 39319566 39729458 39959405 40479324 40549229 40139163 39449130 38799140 38179223
from SPC Mesoscale Discussions http://bit.ly/2L1lJVd
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