Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Fri Apr 28 2017 Valid 290100Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN PLAINS TO THE OZARK PLATEAU... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF THE SOUTHERN PLAINS TO THE OH VALLEY... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN TX PANHANDLE TO WESTERN MD... ...SUMMARY... Scattered severe thunderstorms are expected to concentrate near the Ohio River from southern Illinois to southern Ohio this evening and across the southern Great Plains and Ozarks tonight. Large hail, a few tornadoes, primarily across the southern Plains, and damaging winds are anticipated. ...Evening Update... Severe thunderstorms have struggled to organize across the OH Valley in the presence of significant large-scale mid-level height rises. However, a long-lived cluster of mostly weak convection has migrated across IL into IN/OH where storms have gradually strengthened, especially along the southern fringe of this precip shield near the OH River. 00Z soundings across this region exhibit strong veering wind profiles with height and a modestly unstable air mass primarily across the lower OH River Valley. ILN sounding was not particularly unstable but BNA was quite moist/unstable with MUCAPE on the order of 3000 J/kg. Primary negative for significant organized severe thunderstorms across the OH Valley tonight will be the meager large-scale forcing for ascent. Even so, scattered severe storms remain possible and have focused severe probs near the OH River along southern fringe of aforementioned MCS where greater buoyancy will overlap with higher concentration of storms. Strong forcing for ascent is beginning to spread across the southern Great Plains from NM into southwest KS. Mid levels are moistening significantly across this region and precipitation is spreading/developing rapidly atop cool boundary layer. Earlier thoughts regarding the convective evolution over the southern Plains remain. Low-level warm advection should increase over the next few hours and a marked increase in thunderstorms is expected near the TX Panhandle/OK border by mid-late evening. This activity will spread east along well-defined frontal zone draped along the I-44 corridor with activity expected into the Ozark Plateau by sunrise Saturday. ..Darrow.. 04/29/2017Read more
from SPC Forecast Products http://ift.tt/rxAC6Z
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