Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Mar 15 2025 Valid 152000Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN MISSISSIPPI AND WEST CENTRAL ALABAMA... ...SUMMARY... A tornado outbreak is ongoing across the central Gulf Coast States. Numerous significant tornadoes, some of which should be long-track and potentially violent, may continue into this evening. The severe risk should spread across eastern Mississippi through the remainder of the afternoon into the evening, and reach western parts of the Florida Panhandle and Georgia tonight. ...20z Update... Dangerous tornado outbreak is ongoing and expected to continue this evening over the Southeast. The main change for the 20z outlook was to expand the categorical High Risk a bit over southwestern AL and southern MS, and trim out the severe areas west. A squadron of intense tornadic supercells will continue east/northeast over eastern MS, and much of western AL this afternoon and into the evening. The strongest low-level theta-E advection is occurring across southeastern MS and west/southwestern AL. Strong ascent and intense low-level shear from a 60-70 kt low-level jet should continue to focus a nearly optimal supercell/tornado environment over this area through this evening. Upscale growth into one or more bowing line segments will be possible late this evening over eastern AL and western GA. Strong shear will continue the risk for tornadoes along with damaging gusts. Over northern AL and southern TN, widespread convection has resulted in a messy storm mode with embedded supercell structures. A strong meso low (994 mb) will continue northeast along the MS River Valley supporting impressive low-level shear (0-1 km SRH of 250-500 m2/s2) despite the less favorable thermodynamics. Tornadoes (some strong) and numerous damaging wind gusts are possible with the embedded supercells and bowing segments as a more linear storm mode should begin to emerge through this evening. ..Lyons.. 03/15/2025 .PREV DISCUSSION... /ISSUED 1134 AM CDT Sat Mar 15 2025/ ...Southeast into the Tennessee Valley... No changes have been made to the High Risk area across the Southeast. Multiple supercells are ongoing late this morning across southeast LA into MS, along and east of a convectively reinforced baroclinic zone. A very favorable parameter space exists across the Southeast for severe thunderstorms, which will likely help maintain ongoing supercells and small line segments. Current expectations are for the most favorable strong to intense tornado environment to continue across MS this afternoon and evening, with moderate instability and ample low-level and deep-layer shear already in place. The tornado threat will spread eastward into AL and southern TN this afternoon and evening, and eventually into parts of the FL Panhandle, western/central GA, and eastern TN overnight in tandem with an ejecting southern-stream shortwave trough and related intense low-level jet. Both large hail and severe/damaging winds will also be a threat with these supercells. Upscale growth into one or more bowing line segments will be possible, especially with northward extent into the TN Valley and eastward into GA, where potentially numerous to widespread severe/damaging winds may occur. Reference Mesoscale Discussions 199, 200, and 201 for more information on the near-term severe threat across the Southeast. ...Southern Appalachians... As an upper trough pivots east into the region late tonight, strong low-level warm/moist advection will contribute to a gradually destabilizing airmass. Despite weaker buoyancy with eastward extent over northeast GA into the western Carolinas, very intense low to mid-level flow will aid in maintaining a risk for a few supercells and line segments into a more limited thermodynamic environment. This will potentially yield a risk for damaging gusts and an isolated tornado threat through early Sunday morning. ...Ohio Valley into Southern Great Lakes... Guidance maintains a belt of strong 850 mb flow through midday, before an intensification of the northern periphery of a low-level jet extending from the central Gulf Coast into the Mid South overspreads the region. Uncertainty remains regarding the magnitude of destabilization behind earlier convective activity, and its resultant effects on severe potential. Most guidance generally shows only weak buoyancy (at or below 500 J/kg of MUCAPE), but some airmass recovery in the wake of earlier thunderstorms may occur over IN into OH and vicinity. Read more