Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
369 ACUS03 KWNS 270731 SWODY3 SPC AC 270730 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Jun 27 2024 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OH INTO WESTERN PA AND NORTHERN WV... ...SUMMARY... Damaging winds and a couple tornadoes are possible across parts of the upper Ohio Valley and Northeast on Saturday. ...Parts of the Ohio Valley and Northeast... A mid/upper-level shortwave trough and related surface low are forecast to move from parts of the upper Midwest into Ontario/Quebec on Saturday, while a trailing shortwave will move southeastward across the upper Great Lakes during the evening. One or more MCVs may move eastward within a belt of westerly midlevel flow from parts of the Midwest/Ohio Valley into the Northeast. A cold front trailing from the primary surface low will move eastward across parts of the Midwest, Ohio Valley, and Great Lakes, and eventually into parts of the Northeast by Sunday morning. Rich low-level moisture is forecast to stream northeastward along/ahead of the cold front, aided by a belt of relatively strong southwesterly 850 mb flow. Midlevel lapse rates are expected to remain weak, but low 70s F dewpoints and modest diurnal heating could support moderate to locally strong buoyancy by mid/late afternoon, though the influence of early-day convection on destabilization remains rather uncertain. Scattered thunderstorms may develop during the afternoon from OH into western PA, with more isolated development possible along the trailing front into the lower OH Valley. Deep-layer shear will be sufficient for organized convection, and a few supercells and/or organized clusters could develop and move eastward during the afternoon into the evening, with a threat of scattered damaging wind. Some tornado threat could also evolve, in the presence of rich moisture and somewhat favorable low-level shear/SRH. A Slight Risk has been added from OH into western PA. Some expansion of this risk area is possible with time, depending on extent of destabilization farther east, and storm coverage farther southwest. ...Ozark Region into the south-central Plains... Strong buoyancy is forecast to develop during the afternoon along the trailing cold front from parts of southern KS/MO into northern OK/AR. Deep-layer flow is expected to be rather weak, but modest veering with height may support effective shear of 20-30 kt near the front. Storm coverage along the front in this region remains somewhat uncertain, but isolated strong to severe storms will be possible, with a threat of localized severe gusts and possibly some hail. A couple stronger storms may also develop within a post-frontal regime across parts of the southern/central High Plains. ..Dean.. 06/27/2024 $$