SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Mon Mar 07 2022 Valid 071300Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE VALLEY/APPALACHIANS TO MID-ATLANTIC STATES... ...SUMMARY... Locally damaging wind gusts may accompany isolated thunderstorms from the Tennessee Valley and Appalachians to the coastal Mid-Atlantic today into this evening. ...Tennessee Valley/Appalachians to Mid-Atlantic coast... A lead shortwave trough/related jet streak, which are embedded within phasing westerlies, will quick spread northeastward from the Midwest to the Northeast and New England by tonight, while a secondary southern-stream trough evolves the southern Rockies. This will result in neutral height tendencies/limited overall forcing for ascent, as well as some mid-level warming, where moisture is more readily available across the Southeast States/southern Appalachians ahead of a cold front. Early this morning, a nearly continuous northeast/southwest-oriented line of thunderstorms extends from central Kentucky to Middle Tennessee and northern Mississippi. There has been a general updraft/downdraft intensity decrease in the predawn hours, but the organization of the line has nonetheless been maintained in the presence of weak buoyancy and very strong low-level/deep-layer shear. On the southern end, across the Tennessee Valley and southern Appalachians vicinity, low-level convergence may tend to weaken today, and while considerable cloud cover exists ahead of the cold front/convective line, a semi-moist air mass persists (60s F surface dewpoints) and a modest intensity boost could occur into this afternoon as the boundary layer warms. This may result in the potential maintenance of a semi-broken squall line and other bands of storms. Isolated damaging winds are the primary hazard. Farther north, across the central/northern Appalachians vicinity to the coastal Mid-Atlantic, a modest intensity/organizational uptick may occur near the cold front this afternoon as the cyclone continues to deepen from the Ohio Valley toward the Northeast/New England. Surface dewpoints will be limited to the 50s F, but a plume to relatively steep mid-level lapse rates may contribute to weak near-surface-rooted buoyancy, potentially with areas of a coupled hundred J/kg SBCAPE. This may be sufficient for an increasing potential for convectively augmented wind gusts, even in the relative absence of lightning, across the Appalachians this afternoon, and east of the mountains and toward the coastal Mid-Atlantic by early evening. Localized wind damage may occur. ..Guyer/Mosier.. 03/07/2022
