SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue Sep 05 2023 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSISSIPPI VALLEY...LOWER OHIO VALLEY AND CENTRAL GREAT LAKES... ...SUMMARY... Thunderstorms associated with marginally severe winds will be possible on Wednesday from parts of the mid Mississippi Valley north-northeastward into parts of lower Michigan. A potential for hail is also expected in parts of the mid Mississippi and lower Ohio Valleys. ...Mid Mississippi Valley/Lower Ohio Valley/Central Great Lakes... An upper-level trough will move eastward across the mid to upper Mississippi Valley on Wednesday. An associated cold front will advance eastward into the southwestern Great Lakes and lower Ohio Valley. Surface dewpoints ahead of the front are forecast to be in the upper 60s and lower 70s F. The moist airmass will contribute to the development of moderate instability by afternoon. Isolated to scattered thunderstorms appear likely to form near and ahead of the front during the mid afternoon. Several small convective clusters or line segments will be possible as cell coverage increases during the late afternoon and early evening. Near the axis of strongest instability, NAM forecast soundings in the late afternoon in far western Kentucky have MLCAPE peaking near 4000 J/kg, with 0-6 km shear around 30 knots. Flow above 500 mb is forecast to be relatively weak. This will likely keep the primary mode multicellular. As low-level lapse rates become steep in the mid afternoon, the stronger multicells could be accompanied with marginally severe winds. Hail could also occur, mainly in the mid Mississippi and lower Ohio Valleys where the strongest instability is forecast. Further north into the southern Great Lakes, moderate instability is forecast to develop ahead the cold front by afternoon. As low-level convergence increases along the front and near a surface low in Lower Michigan, a few marginally severe gusts will be possible with the stronger multicells. The isolated wind-damage threat will likely be greatest along the leading edge of the faster-moving short line segments. ..Broyles.. 09/05/2023
