SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0744 AM CDT Sat Apr 01 2023 Valid 011300Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE EAST... ...SUMMARY... Scattered damaging winds and a couple tornadoes will be possible across parts of the Northeast this afternoon and evening. Isolated to scattered damaging winds and a tornado or two remain possible across parts of the Southeast through this afternoon. ...Northeast... A vigorous shortwave trough centered over southern Lake MI will rapidly progress off the Northeast/southern New England coast by this evening. Strong forcing for ascent will overspread the Lower Great Lakes towards midday, with initial thunderstorm development expected across north-central/northeast OH. While 12Z observed soundings sampled negligible buoyancy, with upper 40s to low 50s surface dew points over the Upper OH Valley and full insolation ahead of the wave, weak MLCAPE to around 500 J/kg is anticipated within a rather steep low to mid-level lapse rate environment. Very strong deep-layer shear and enlarged low-level hodographs will support a broken linear band with embedded supercells into western/northern PA and southern NY. Relative paucity of buoyancy across central PA should tend towards storms producing damaging winds as the primary hazard, with potential for any organized clustering to temporarily weaken. Richer boundary-layer moisture should remain present closer to the coastal plain across the DE and Lower Hudson Valleys. Pervasive cloud coverage should decrease somewhat by late afternoon, which would support a conditional supercell environment. A few CAMs indicate one to two leading discrete supercells across portions of the DE Valley. Should they be sustained, tornadoes, hail, and damaging winds would all be possible. The more probable scenario is for the fast-moving convection along the front spreading east and impinging on the relatively greater moisture. This may yield an uptick in severe wind potential until storms shift off the coast. ...Southeast... Deep-layer flow will gradually become more westerly with time as the strong upper low advances east across the OH Valley. This evolution will encourage pre-frontal convection that currently extends from north GA to central AL to advance east-southeast through the period. While the primary large-scale forcing will spread well north of this region, deep-layer flow will be strong and organized clusters/short-line segments are expected. Damaging winds should be the primary concern, though some risk for a tornado or two is also evident. ..Grams/Goss.. 04/01/2023
