SPC Mar 20, 2017 0600 UTC Day 2 Convective Outlook

By Newsroom America Feeds at 20 Mar 2017

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Mar 20 2017 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS... ...SUMMARY... A marginal threat for hail and strong gusty winds will be possible in parts of the Tennessee Valley and southern Appalachians on Tuesday. ...Tennessee Valley/Southern Appalachians... West to northwest mid-level flow will be in place across the eastern half of the contiguous United States on Tuesday. At the surface, a cold front is forecast to advance southward into the Tennessee Valley during the day. Although large-scale ascent should remain weak along the front, the models still agree on convective initiation over Tennessee during the afternoon due to surface heating and enhanced low-level convergence. It appears that a convective cluster will develop over southeast Missouri and move east southeastward into middle Tennessee during the late afternoon reaching the southern Appalachian mountains by early evening. NAM and GFS forecast soundings along this corridor from 21Z to 00Z show SBCAPE around 1500 J/kg with 0-6 km shear near 35 kt. Winds are unidirectional from the west northwest in the low to mid-levels with steep low-level lapse rates. This may support an isolated wind-damage threat. A hail threat will also be possible with the stronger multicell updrafts. The NAM model suggests that the convection could remain just behind the front suggesting that outflow could be undercut. This combined with a lack of large-scale ascent will potentially marginalize the severe threat. ..Broyles.. 03/20/2017 Read more



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