SPC Aug 8, 2024 0600 UTC Day 2 Convective Outlook
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CDT Wed Aug 07 2024 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY INTO FRIDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NEW YORK STATE...PARTS OF SOUTHERN VERMONT AND NEW HAMPSHIRE...WESTERN MASSACHUSETTS...CONNECTICUT AND LONG ISLAND...NEW JERSEY...EASTERN PENNSYLVANIA...CENTRAL MARYLAND AND THE EASTERN SHORE OF MARYLAND...DELAWARE...PARTS OF EASTERN VIRGINIA AND THE DISTRICT OF COLUMBIA... ...SUMMARY... There may be at least some continuing risk for tornadoes in advance of the remnant low of Debby, spreading across parts of the northern Mid Atlantic and adjacent portions of New England. ...Synopsis... It still appears that an initially prominent ridge will generally be maintained over the higher latitudes of North America through this period, though its mid-level height center may begin to become suppressed to the east-southeast of the Canadian Northwest Territories. Some eastward redevelopment of a significant mid-level low evolving to its southeast may also commence, as a couple of embedded perturbations pivot around its circulation center near the upper Great Lakes region. In lower-levels, pattern developments to the northeast and east of the Great Lakes region remain a bit more unclear. A modest initial cyclone, to the north/northeast of Lake Superior at 12Z Friday, may gradually occlude, with varied model output then suggesting that modest secondary cyclogenesis may ensue somewhere across southern Ontario and the lower Great Lakes region into the upper St. Lawrence Valley by 12Z Saturday. At the same time, Debby's remnant low is forecast to accelerate north of the Virginia Piedmont by early Friday, before accelerating north-northeastward and passing near/just west of the Poconos and Catskills vicinity by Friday evening. Eventually, it may interact with a frontal zone trailing the evolving cyclone to the north, and perhaps merge into the cyclone, but these details remain uncertain. ...Northern Mid Atlantic/New England... Severe probabilities have been adjusted north-northeastward, based on westward and accelerated adjustments to the official forecast track. Despite the weakening trends to Debby, models suggest that the evolution of sizable clockwise-curved low-level hodographs and appreciable boundary-layer buoyancy may be maintained at least through the daytime hours Friday. It appears that the most favorable environment for convection which could become capable of producing tornadoes will be focused near the stronger surface pressure falls, north through east of the accelerating low-level circulation, and just ahead of the mid-level warm core. This may be in the process of overspreading the Chesapeake/Delmarva vicinity as daytime heating contributes to boundary-layer destabilization, before spreading northward across eastern Pennsylvania and New Jersey, much of southeastern New York and adjacent portions of western New England by early Friday evening. Even if the clockwise curvature to the low-level hodographs does not remain as large as some forecast soundings indicate, downward mixing of strong southerly ambient wind fields (including 40-50+ kt in the 850-700 mb layer) may still contribute to potentially damaging surface gusts in the stronger convection. While it seems that this risk may wane overnight Friday, it is possible that low severe probabilities may need to be extended northeastward in later outlooks for this period. Severe probabilities might also still need to be increased across parts of the current marginal risk area, if/when lingering uncertainties become better resolved. ..Kerr.. 08/08/2024 Read more
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CDT Wed Aug 07 2024 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY INTO FRIDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NEW YORK STATE...PARTS OF SOUTHERN VERMONT AND NEW HAMPSHIRE...WESTERN MASSACHUSETTS...CONNECTICUT AND LONG ISLAND...NEW JERSEY...EASTERN PENNSYLVANIA...CENTRAL MARYLAND AND THE EASTERN SHORE OF MARYLAND...DELAWARE...PARTS OF EASTERN VIRGINIA AND THE DISTRICT OF COLUMBIA... ...SUMMARY... There may be at least some continuing risk for tornadoes in advance of the remnant low of Debby, spreading across parts of the northern Mid Atlantic and adjacent portions of New England. ...Synopsis... It still appears that an initially prominent ridge will generally be maintained over the higher latitudes of North America through this period, though its mid-level height center may begin to become suppressed to the east-southeast of the Canadian Northwest Territories. Some eastward redevelopment of a significant mid-level low evolving to its southeast may also commence, as a couple of embedded perturbations pivot around its circulation center near the upper Great Lakes region. In lower-levels, pattern developments to the northeast and east of the Great Lakes region remain a bit more unclear. A modest initial cyclone, to the north/northeast of Lake Superior at 12Z Friday, may gradually occlude, with varied model output then suggesting that modest secondary cyclogenesis may ensue somewhere across southern Ontario and the lower Great Lakes region into the upper St. Lawrence Valley by 12Z Saturday. At the same time, Debby's remnant low is forecast to accelerate north of the Virginia Piedmont by early Friday, before accelerating north-northeastward and passing near/just west of the Poconos and Catskills vicinity by Friday evening. Eventually, it may interact with a frontal zone trailing the evolving cyclone to the north, and perhaps merge into the cyclone, but these details remain uncertain. ...Northern Mid Atlantic/New England... Severe probabilities have been adjusted north-northeastward, based on westward and accelerated adjustments to the official forecast track. Despite the weakening trends to Debby, models suggest that the evolution of sizable clockwise-curved low-level hodographs and appreciable boundary-layer buoyancy may be maintained at least through the daytime hours Friday. It appears that the most favorable environment for convection which could become capable of producing tornadoes will be focused near the stronger surface pressure falls, north through east of the accelerating low-level circulation, and just ahead of the mid-level warm core. This may be in the process of overspreading the Chesapeake/Delmarva vicinity as daytime heating contributes to boundary-layer destabilization, before spreading northward across eastern Pennsylvania and New Jersey, much of southeastern New York and adjacent portions of western New England by early Friday evening. Even if the clockwise curvature to the low-level hodographs does not remain as large as some forecast soundings indicate, downward mixing of strong southerly ambient wind fields (including 40-50+ kt in the 850-700 mb layer) may still contribute to potentially damaging surface gusts in the stronger convection. While it seems that this risk may wane overnight Friday, it is possible that low severe probabilities may need to be extended northeastward in later outlooks for this period. Severe probabilities might also still need to be increased across parts of the current marginal risk area, if/when lingering uncertainties become better resolved. ..Kerr.. 08/08/2024 Read more
