SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Tue Apr 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY... ...SUMMARY... Isolated severe storms capable of producing large hail and locally damaging gusts will be possible across portions of the Tennessee Valley on Thursday afternoon and evening. ...Synopsis... A positively tilted large-scale trough and accompanying midlevel speed maximum will move southeastward from the Middle/Upper MS Valley to the southern Appalachians through the period. At the same time, a weak surface low will drift east-southeastward from the Midwest into the central Appalachians, while a related cold front overspreads the TN Valley during the afternoon/evening. ...Tennessee Valley... Aided by strengthening DCVA in the left-exit region of the midlevel jet, isolated to widely scattered thunderstorms are expected along the cold front as it moves southeastward across the TN Valley during the afternoon and evening hours. Beneath steepening midlevel lapse rates, diurnal heating of a partially modified Gulf air mass will yield upwards of 1000 J/kg MUCAPE along the front. Despite the somewhat marginal buoyancy, 50-60 kt of effective shear (characterized by a long/straight hodograph) will support a few organized/rotating storms -- both ahead of and behind the southward-moving front. Weak/veered low-level flow will generally limit the strength of forcing along the front, which should favor a semi-discrete mode and the potential for large hail and locally damaging gusts. ..Weinman.. 04/08/2025