Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 AM CDT Sat Aug 05 2023 ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE SOUTHERN APPALACHIANS...MID-ATLANTIC AND NORTHEAST U.S.... ...SUMMARY... Severe thunderstorms are possible Monday across portions of the southern Appalachians, mid-Atlantic and northeast U.S. ...Mid-Atlantic/northeast... As an upper-level trough moves slowly east across the region Monday, latest deterministic and ensemble guidance suggests a favorably sheared environment for organized severe storms including supercells will exist over a rather large area from the southern Appalachians northeast into the mid-Atlantic/northeast U.S. Heating of a seasonably moist boundary layer, combined with somewhat steeper mid-level lapse rates associated with the eastern fringe of an EML extending east from the southern Plains, will contribute to moderate-strong MLCAPE across the area. Thunderstorms may be ongoing at 12z Monday over portions of PA/NY and vicinity with a weak mid-level impulse and warm advection, and lingering clouds/precipitation will likely influence the degree of destabilization in these areas. Thunderstorms should develop/intensify during the afternoon in advance of a cold front aided by large-scale ascent, with both supercell and multicell storm structures likely. Relatively long hodographs may support splitting storms with a risk for large hail, and seasonably strong low-level wind fields will favor scattered damaging gusts, especially where low-level lapse rates are steepened through stronger heating. A risk for a few tornadoes may also exist, especially across portions of the mid-Atlantic and northeast where low-level hodograph curvature is most pronounced. Have opted to continue a broad 15%/Slight Risk area with this outlook, however higher severe probabilities may ultimately be warranted for portions of the area as mesoscale details come into better focus.
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