Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Sun May 26 2024 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN OZARKS TO PARTS OF THE OHIO VALLEY REGION... ...SUMMARY... Multiple rounds of severe storms are possible from the Ozarks and nearby Mississippi Valley into the Ohio Valley States today, with threats for tornadoes, severe gusts and occasional large hail. ...Synopsis... A progressive mid/upper-level pattern is apparent across the CONUS, perturbed mainly by a synoptic-scale trough initially over the central High Plains, and related cyclonic flow and embedded vorticity maxima/shortwaves over the Central States. The trough should shift eastward to WI, eastern IA, northern MO and central OK by 00Z, then over the Upper Great Lakes, Lower MI, and the lower Ohio Valley by 12Z tomorrow. At the surface, 11Z analysis showed a primary synoptic low over southwestern IA, with warm front across western IL behind convective outflow, and ahead of the outflow from central IL across southern IN to northeastern KY. The warm front should move slowly northward across the Ohio Valley through the afternoon. The cold front was drawn from the IA low southwestward to another low between ICT-PNC, then across western OK and northwest TX. This front will overtake a dryline today over northwest/west-central TX. By 00Z, the cold front should extend from a triple-point low near MSN across central IL, southern MO, southeastern OK, and north-central/central TX. By 12Z, the cold front should reach eastern IN, central KY, and western TN, becoming quasistationary southwestward over the Arklatex to central TX. The cold front will be preceded by an MCS outflow boundary over parts of the Ozarks and Ohio Valley region today. ...Ozarks/Arklatex to Ohio/Tennessee Valleys and south-central Appalachians... A complex, multi-episode severe scenario is apparent, still bearing some important mesoscale uncertainties. However, probabilities supporting an "enhanced" category appear solidly warranted over most of the original area that has not been too convectively processed, and mesoscale foci may yield denser swaths of severe (wind in particular) within that remaining broad corridor. An ongoing severe MCS, with embedded supercells and bowing segments and a history of several overnight tornadoes in the Ozarks, will continue to pose a threat for all severe hazards (including tornadoes) for at least the next several hours past midday. This threat should persist as activity exits the Ozarks, crosses the adjoining Mississippi Valley, and moves into parts of the lower Ohio Valley vicinity. Some northward expansion toward/past the warm front is possible over the Ohio Valley. This activity should only gradually outpace the most favorable buoyancy as it approaches the Appalachians, and may still have a severe threat across the higher terrain. Confidence in its persistence is heightened by the presence of at least one MCV over the eastern Ozarks, which should enhance ascent and lower/middle-tropospheric vertical wind profiles/shear on the mesoscale. Organization of these thunderstorms should continue to take advantage of forced lift with cold pools, as well as lift from internal rotational dynamics of supercells and bookend vortices, to overcome modest MLCINH this morning through midday. Inflow air will contain rich low-level moisture (surface dewpoints commonly in the upper 60s to low 70s F, locally higher), and will be diurnally destabilizing from heating and warm advection near and south of the warm front. For near-term guidance, see SPC Tornado Watch 314 and related mesoscale discussions. Details of subsequent round(s) of convection still remain to be resolved, based substantially on the character and extent of poleward return of the outflow boundary from the leading activity. As such, further modifications (some substantial) may be needed to especially western parts of the outlook areas today. One zone of relatively maximized deep ascent appears to be associated with passage of the convectively reinforced prefrontal boundary over parts of MO and southeastern KS, initially penetrating outflow air from the leading activity. This regime should continue to benefit from large-scale DCVA/ascent aloft, related to the shortwave trough and closely associated convectively induced/enhanced vorticity fields. Activity interacting with the outflow boundary's theta-e gradient, backed near-surface winds, and maximized mesoscale vorticity in low levels should pose the greatest potential for tornadoes. However the afternoon/evening tornado risk is not yet focused tightly, due to uncertainties regarding the evolution of a boundary still being produced at this time. The general large-scale ascent, along with direct frontal lift and heating of a very moist airmass in the warm sector, also should support at least isolated to widely scattered, near-frontal convective development farther south across parts of AR and eastern OK, southwest of the outflow boundary. This activity, including supercells, should occur in an environment of stronger EML-related MLCINH for much of the day, but also, steep midlevel lapse rates, optimal moisture (surface dewpoints commonly low-mid 70s F), and weakening capping with time this afternoon. Despite some veering of near-surface winds, which may limit convergence, any activity that develops still will occur in an environment of 50-65-kt effective- shear magnitudes, and peak local MLCAPE commonly in the 3500-4500 J/kg range. Forecast hodographs and 2D hail models suggest very large hail of 3+ inches in diameter may occur with any sustained, relatively discrete storm this afternoon into early evening. Additional development is possible farther east in the warm sector, near and east of the Mississippi River and south of the MCS outflow, off the eastern rim of the EML where MLCINH is weaker but moisture and heating are strong. ..Edwards/Goss.. 05/26/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Sun May 26 2024 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN OZARKS TO PARTS OF THE OHIO VALLEY REGION... ...SUMMARY... Multiple rounds of severe storms are possible from the Ozarks and nearby Mississippi Valley into the Ohio Valley States today, with threats for tornadoes, severe gusts and occasional large hail. ...Synopsis... A progressive mid/upper-level pattern is apparent across the CONUS, perturbed mainly by a synoptic-scale trough initially over the central High Plains, and related cyclonic flow and embedded vorticity maxima/shortwaves over the Central States. The trough should shift eastward to WI, eastern IA, northern MO and central OK by 00Z, then over the Upper Great Lakes, Lower MI, and the lower Ohio Valley by 12Z tomorrow. At the surface, 11Z analysis showed a primary synoptic low over southwestern IA, with warm front across western IL behind convective outflow, and ahead of the outflow from central IL across southern IN to northeastern KY. The warm front should move slowly northward across the Ohio Valley through the afternoon. The cold front was drawn from the IA low southwestward to another low between ICT-PNC, then across western OK and northwest TX. This front will overtake a dryline today over northwest/west-central TX. By 00Z, the cold front should extend from a triple-point low near MSN across central IL, southern MO, southeastern OK, and north-central/central TX. By 12Z, the cold front should reach eastern IN, central KY, and western TN, becoming quasistationary southwestward over the Arklatex to central TX. The cold front will be preceded by an MCS outflow boundary over parts of the Ozarks and Ohio Valley region today. ...Ozarks/Arklatex to Ohio/Tennessee Valleys and south-central Appalachians... A complex, multi-episode severe scenario is apparent, still bearing some important mesoscale uncertainties. However, probabilities supporting an "enhanced" category appear solidly warranted over most of the original area that has not been too convectively processed, and mesoscale foci may yield denser swaths of severe (wind in particular) within that remaining broad corridor. An ongoing severe MCS, with embedded supercells and bowing segments and a history of several overnight tornadoes in the Ozarks, will continue to pose a threat for all severe hazards (including tornadoes) for at least the next several hours past midday. This threat should persist as activity exits the Ozarks, crosses the adjoining Mississippi Valley, and moves into parts of the lower Ohio Valley vicinity. Some northward expansion toward/past the warm front is possible over the Ohio Valley. This activity should only gradually outpace the most favorable buoyancy as it approaches the Appalachians, and may still have a severe threat across the higher terrain. Confidence in its persistence is heightened by the presence of at least one MCV over the eastern Ozarks, which should enhance ascent and lower/middle-tropospheric vertical wind profiles/shear on the mesoscale. Organization of these thunderstorms should continue to take advantage of forced lift with cold pools, as well as lift from internal rotational dynamics of supercells and bookend vortices, to overcome modest MLCINH this morning through midday. Inflow air will contain rich low-level moisture (surface dewpoints commonly in the upper 60s to low 70s F, locally higher), and will be diurnally destabilizing from heating and warm advection near and south of the warm front. For near-term guidance, see SPC Tornado Watch 314 and related mesoscale discussions. Details of subsequent round(s) of convection still remain to be resolved, based substantially on the character and extent of poleward return of the outflow boundary from the leading activity. As such, further modifications (some substantial) may be needed to especially western parts of the outlook areas today. One zone of relatively maximized deep ascent appears to be associated with passage of the convectively reinforced prefrontal boundary over parts of MO and southeastern KS, initially penetrating outflow air from the leading activity. This regime should continue to benefit from large-scale DCVA/ascent aloft, related to the shortwave trough and closely associated convectively induced/enhanced vorticity fields. Activity interacting with the outflow boundary's theta-e gradient, backed near-surface winds, and maximized mesoscale vorticity in low levels should pose the greatest potential for tornadoes. However the afternoon/evening tornado risk is not yet focused tightly, due to uncertainties regarding the evolution of a boundary still being produced at this time. The general large-scale ascent, along with direct frontal lift and heating of a very moist airmass in the warm sector, also should support at least isolated to widely scattered, near-frontal convective development farther south across parts of AR and eastern OK, southwest of the outflow boundary. This activity, including supercells, should occur in an environment of stronger EML-related MLCINH for much of the day, but also, steep midlevel lapse rates, optimal moisture (surface dewpoints commonly low-mid 70s F), and weakening capping with time this afternoon. Despite some veering of near-surface winds, which may limit convergence, any activity that develops still will occur in an environment of 50-65-kt effective- shear magnitudes, and peak local MLCAPE commonly in the 3500-4500 J/kg range. Forecast hodographs and 2D hail models suggest very large hail of 3+ inches in diameter may occur with any sustained, relatively discrete storm this afternoon into early evening. Additional development is possible farther east in the warm sector, near and east of the Mississippi River and south of the MCS outflow, off the eastern rim of the EML where MLCINH is weaker but moisture and heating are strong. ..Edwards/Goss.. 05/26/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Sun May 26 2024 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN OZARKS TO PARTS OF THE OHIO VALLEY REGION... ...SUMMARY... Multiple rounds of severe storms are possible from the Ozarks and nearby Mississippi Valley into the Ohio Valley States today, with threats for tornadoes, severe gusts and occasional large hail. ...Synopsis... A progressive mid/upper-level pattern is apparent across the CONUS, perturbed mainly by a synoptic-scale trough initially over the central High Plains, and related cyclonic flow and embedded vorticity maxima/shortwaves over the Central States. The trough should shift eastward to WI, eastern IA, northern MO and central OK by 00Z, then over the Upper Great Lakes, Lower MI, and the lower Ohio Valley by 12Z tomorrow. At the surface, 11Z analysis showed a primary synoptic low over southwestern IA, with warm front across western IL behind convective outflow, and ahead of the outflow from central IL across southern IN to northeastern KY. The warm front should move slowly northward across the Ohio Valley through the afternoon. The cold front was drawn from the IA low southwestward to another low between ICT-PNC, then across western OK and northwest TX. This front will overtake a dryline today over northwest/west-central TX. By 00Z, the cold front should extend from a triple-point low near MSN across central IL, southern MO, southeastern OK, and north-central/central TX. By 12Z, the cold front should reach eastern IN, central KY, and western TN, becoming quasistationary southwestward over the Arklatex to central TX. The cold front will be preceded by an MCS outflow boundary over parts of the Ozarks and Ohio Valley region today. ...Ozarks/Arklatex to Ohio/Tennessee Valleys and south-central Appalachians... A complex, multi-episode severe scenario is apparent, still bearing some important mesoscale uncertainties. However, probabilities supporting an "enhanced" category appear solidly warranted over most of the original area that has not been too convectively processed, and mesoscale foci may yield denser swaths of severe (wind in particular) within that remaining broad corridor. An ongoing severe MCS, with embedded supercells and bowing segments and a history of several overnight tornadoes in the Ozarks, will continue to pose a threat for all severe hazards (including tornadoes) for at least the next several hours past midday. This threat should persist as activity exits the Ozarks, crosses the adjoining Mississippi Valley, and moves into parts of the lower Ohio Valley vicinity. Some northward expansion toward/past the warm front is possible over the Ohio Valley. This activity should only gradually outpace the most favorable buoyancy as it approaches the Appalachians, and may still have a severe threat across the higher terrain. Confidence in its persistence is heightened by the presence of at least one MCV over the eastern Ozarks, which should enhance ascent and lower/middle-tropospheric vertical wind profiles/shear on the mesoscale. Organization of these thunderstorms should continue to take advantage of forced lift with cold pools, as well as lift from internal rotational dynamics of supercells and bookend vortices, to overcome modest MLCINH this morning through midday. Inflow air will contain rich low-level moisture (surface dewpoints commonly in the upper 60s to low 70s F, locally higher), and will be diurnally destabilizing from heating and warm advection near and south of the warm front. For near-term guidance, see SPC Tornado Watch 314 and related mesoscale discussions. Details of subsequent round(s) of convection still remain to be resolved, based substantially on the character and extent of poleward return of the outflow boundary from the leading activity. As such, further modifications (some substantial) may be needed to especially western parts of the outlook areas today. One zone of relatively maximized deep ascent appears to be associated with passage of the convectively reinforced prefrontal boundary over parts of MO and southeastern KS, initially penetrating outflow air from the leading activity. This regime should continue to benefit from large-scale DCVA/ascent aloft, related to the shortwave trough and closely associated convectively induced/enhanced vorticity fields. Activity interacting with the outflow boundary's theta-e gradient, backed near-surface winds, and maximized mesoscale vorticity in low levels should pose the greatest potential for tornadoes. However the afternoon/evening tornado risk is not yet focused tightly, due to uncertainties regarding the evolution of a boundary still being produced at this time. The general large-scale ascent, along with direct frontal lift and heating of a very moist airmass in the warm sector, also should support at least isolated to widely scattered, near-frontal convective development farther south across parts of AR and eastern OK, southwest of the outflow boundary. This activity, including supercells, should occur in an environment of stronger EML-related MLCINH for much of the day, but also, steep midlevel lapse rates, optimal moisture (surface dewpoints commonly low-mid 70s F), and weakening capping with time this afternoon. Despite some veering of near-surface winds, which may limit convergence, any activity that develops still will occur in an environment of 50-65-kt effective- shear magnitudes, and peak local MLCAPE commonly in the 3500-4500 J/kg range. Forecast hodographs and 2D hail models suggest very large hail of 3+ inches in diameter may occur with any sustained, relatively discrete storm this afternoon into early evening. Additional development is possible farther east in the warm sector, near and east of the Mississippi River and south of the MCS outflow, off the eastern rim of the EML where MLCINH is weaker but moisture and heating are strong. ..Edwards/Goss.. 05/26/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Sun May 26 2024 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN OZARKS TO PARTS OF THE OHIO VALLEY REGION... ...SUMMARY... Multiple rounds of severe storms are possible from the Ozarks and nearby Mississippi Valley into the Ohio Valley States today, with threats for tornadoes, severe gusts and occasional large hail. ...Synopsis... A progressive mid/upper-level pattern is apparent across the CONUS, perturbed mainly by a synoptic-scale trough initially over the central High Plains, and related cyclonic flow and embedded vorticity maxima/shortwaves over the Central States. The trough should shift eastward to WI, eastern IA, northern MO and central OK by 00Z, then over the Upper Great Lakes, Lower MI, and the lower Ohio Valley by 12Z tomorrow. At the surface, 11Z analysis showed a primary synoptic low over southwestern IA, with warm front across western IL behind convective outflow, and ahead of the outflow from central IL across southern IN to northeastern KY. The warm front should move slowly northward across the Ohio Valley through the afternoon. The cold front was drawn from the IA low southwestward to another low between ICT-PNC, then across western OK and northwest TX. This front will overtake a dryline today over northwest/west-central TX. By 00Z, the cold front should extend from a triple-point low near MSN across central IL, southern MO, southeastern OK, and north-central/central TX. By 12Z, the cold front should reach eastern IN, central KY, and western TN, becoming quasistationary southwestward over the Arklatex to central TX. The cold front will be preceded by an MCS outflow boundary over parts of the Ozarks and Ohio Valley region today. ...Ozarks/Arklatex to Ohio/Tennessee Valleys and south-central Appalachians... A complex, multi-episode severe scenario is apparent, still bearing some important mesoscale uncertainties. However, probabilities supporting an "enhanced" category appear solidly warranted over most of the original area that has not been too convectively processed, and mesoscale foci may yield denser swaths of severe (wind in particular) within that remaining broad corridor. An ongoing severe MCS, with embedded supercells and bowing segments and a history of several overnight tornadoes in the Ozarks, will continue to pose a threat for all severe hazards (including tornadoes) for at least the next several hours past midday. This threat should persist as activity exits the Ozarks, crosses the adjoining Mississippi Valley, and moves into parts of the lower Ohio Valley vicinity. Some northward expansion toward/past the warm front is possible over the Ohio Valley. This activity should only gradually outpace the most favorable buoyancy as it approaches the Appalachians, and may still have a severe threat across the higher terrain. Confidence in its persistence is heightened by the presence of at least one MCV over the eastern Ozarks, which should enhance ascent and lower/middle-tropospheric vertical wind profiles/shear on the mesoscale. Organization of these thunderstorms should continue to take advantage of forced lift with cold pools, as well as lift from internal rotational dynamics of supercells and bookend vortices, to overcome modest MLCINH this morning through midday. Inflow air will contain rich low-level moisture (surface dewpoints commonly in the upper 60s to low 70s F, locally higher), and will be diurnally destabilizing from heating and warm advection near and south of the warm front. For near-term guidance, see SPC Tornado Watch 314 and related mesoscale discussions. Details of subsequent round(s) of convection still remain to be resolved, based substantially on the character and extent of poleward return of the outflow boundary from the leading activity. As such, further modifications (some substantial) may be needed to especially western parts of the outlook areas today. One zone of relatively maximized deep ascent appears to be associated with passage of the convectively reinforced prefrontal boundary over parts of MO and southeastern KS, initially penetrating outflow air from the leading activity. This regime should continue to benefit from large-scale DCVA/ascent aloft, related to the shortwave trough and closely associated convectively induced/enhanced vorticity fields. Activity interacting with the outflow boundary's theta-e gradient, backed near-surface winds, and maximized mesoscale vorticity in low levels should pose the greatest potential for tornadoes. However the afternoon/evening tornado risk is not yet focused tightly, due to uncertainties regarding the evolution of a boundary still being produced at this time. The general large-scale ascent, along with direct frontal lift and heating of a very moist airmass in the warm sector, also should support at least isolated to widely scattered, near-frontal convective development farther south across parts of AR and eastern OK, southwest of the outflow boundary. This activity, including supercells, should occur in an environment of stronger EML-related MLCINH for much of the day, but also, steep midlevel lapse rates, optimal moisture (surface dewpoints commonly low-mid 70s F), and weakening capping with time this afternoon. Despite some veering of near-surface winds, which may limit convergence, any activity that develops still will occur in an environment of 50-65-kt effective- shear magnitudes, and peak local MLCAPE commonly in the 3500-4500 J/kg range. Forecast hodographs and 2D hail models suggest very large hail of 3+ inches in diameter may occur with any sustained, relatively discrete storm this afternoon into early evening. Additional development is possible farther east in the warm sector, near and east of the Mississippi River and south of the MCS outflow, off the eastern rim of the EML where MLCINH is weaker but moisture and heating are strong. ..Edwards/Goss.. 05/26/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Sun May 26 2024 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN OZARKS TO PARTS OF THE OHIO VALLEY REGION... ...SUMMARY... Multiple rounds of severe storms are possible from the Ozarks and nearby Mississippi Valley into the Ohio Valley States today, with threats for tornadoes, severe gusts and occasional large hail. ...Synopsis... A progressive mid/upper-level pattern is apparent across the CONUS, perturbed mainly by a synoptic-scale trough initially over the central High Plains, and related cyclonic flow and embedded vorticity maxima/shortwaves over the Central States. The trough should shift eastward to WI, eastern IA, northern MO and central OK by 00Z, then over the Upper Great Lakes, Lower MI, and the lower Ohio Valley by 12Z tomorrow. At the surface, 11Z analysis showed a primary synoptic low over southwestern IA, with warm front across western IL behind convective outflow, and ahead of the outflow from central IL across southern IN to northeastern KY. The warm front should move slowly northward across the Ohio Valley through the afternoon. The cold front was drawn from the IA low southwestward to another low between ICT-PNC, then across western OK and northwest TX. This front will overtake a dryline today over northwest/west-central TX. By 00Z, the cold front should extend from a triple-point low near MSN across central IL, southern MO, southeastern OK, and north-central/central TX. By 12Z, the cold front should reach eastern IN, central KY, and western TN, becoming quasistationary southwestward over the Arklatex to central TX. The cold front will be preceded by an MCS outflow boundary over parts of the Ozarks and Ohio Valley region today. ...Ozarks/Arklatex to Ohio/Tennessee Valleys and south-central Appalachians... A complex, multi-episode severe scenario is apparent, still bearing some important mesoscale uncertainties. However, probabilities supporting an "enhanced" category appear solidly warranted over most of the original area that has not been too convectively processed, and mesoscale foci may yield denser swaths of severe (wind in particular) within that remaining broad corridor. An ongoing severe MCS, with embedded supercells and bowing segments and a history of several overnight tornadoes in the Ozarks, will continue to pose a threat for all severe hazards (including tornadoes) for at least the next several hours past midday. This threat should persist as activity exits the Ozarks, crosses the adjoining Mississippi Valley, and moves into parts of the lower Ohio Valley vicinity. Some northward expansion toward/past the warm front is possible over the Ohio Valley. This activity should only gradually outpace the most favorable buoyancy as it approaches the Appalachians, and may still have a severe threat across the higher terrain. Confidence in its persistence is heightened by the presence of at least one MCV over the eastern Ozarks, which should enhance ascent and lower/middle-tropospheric vertical wind profiles/shear on the mesoscale. Organization of these thunderstorms should continue to take advantage of forced lift with cold pools, as well as lift from internal rotational dynamics of supercells and bookend vortices, to overcome modest MLCINH this morning through midday. Inflow air will contain rich low-level moisture (surface dewpoints commonly in the upper 60s to low 70s F, locally higher), and will be diurnally destabilizing from heating and warm advection near and south of the warm front. For near-term guidance, see SPC Tornado Watch 314 and related mesoscale discussions. Details of subsequent round(s) of convection still remain to be resolved, based substantially on the character and extent of poleward return of the outflow boundary from the leading activity. As such, further modifications (some substantial) may be needed to especially western parts of the outlook areas today. One zone of relatively maximized deep ascent appears to be associated with passage of the convectively reinforced prefrontal boundary over parts of MO and southeastern KS, initially penetrating outflow air from the leading activity. This regime should continue to benefit from large-scale DCVA/ascent aloft, related to the shortwave trough and closely associated convectively induced/enhanced vorticity fields. Activity interacting with the outflow boundary's theta-e gradient, backed near-surface winds, and maximized mesoscale vorticity in low levels should pose the greatest potential for tornadoes. However the afternoon/evening tornado risk is not yet focused tightly, due to uncertainties regarding the evolution of a boundary still being produced at this time. The general large-scale ascent, along with direct frontal lift and heating of a very moist airmass in the warm sector, also should support at least isolated to widely scattered, near-frontal convective development farther south across parts of AR and eastern OK, southwest of the outflow boundary. This activity, including supercells, should occur in an environment of stronger EML-related MLCINH for much of the day, but also, steep midlevel lapse rates, optimal moisture (surface dewpoints commonly low-mid 70s F), and weakening capping with time this afternoon. Despite some veering of near-surface winds, which may limit convergence, any activity that develops still will occur in an environment of 50-65-kt effective- shear magnitudes, and peak local MLCAPE commonly in the 3500-4500 J/kg range. Forecast hodographs and 2D hail models suggest very large hail of 3+ inches in diameter may occur with any sustained, relatively discrete storm this afternoon into early evening. Additional development is possible farther east in the warm sector, near and east of the Mississippi River and south of the MCS outflow, off the eastern rim of the EML where MLCINH is weaker but moisture and heating are strong. ..Edwards/Goss.. 05/26/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Sun May 26 2024 Valid 261300Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN OZARKS TO PARTS OF THE OHIO VALLEY REGION... ...SUMMARY... Multiple rounds of severe storms are possible from the Ozarks and nearby Mississippi Valley into the Ohio Valley States today, with threats for tornadoes, severe gusts and occasional large hail. ...Synopsis... A progressive mid/upper-level pattern is apparent across the CONUS, perturbed mainly by a synoptic-scale trough initially over the central High Plains, and related cyclonic flow and embedded vorticity maxima/shortwaves over the Central States. The trough should shift eastward to WI, eastern IA, northern MO and central OK by 00Z, then over the Upper Great Lakes, Lower MI, and the lower Ohio Valley by 12Z tomorrow. At the surface, 11Z analysis showed a primary synoptic low over southwestern IA, with warm front across western IL behind convective outflow, and ahead of the outflow from central IL across southern IN to northeastern KY. The warm front should move slowly northward across the Ohio Valley through the afternoon. The cold front was drawn from the IA low southwestward to another low between ICT-PNC, then across western OK and northwest TX. This front will overtake a dryline today over northwest/west-central TX. By 00Z, the cold front should extend from a triple-point low near MSN across central IL, southern MO, southeastern OK, and north-central/central TX. By 12Z, the cold front should reach eastern IN, central KY, and western TN, becoming quasistationary southwestward over the Arklatex to central TX. The cold front will be preceded by an MCS outflow boundary over parts of the Ozarks and Ohio Valley region today. ...Ozarks/Arklatex to Ohio/Tennessee Valleys and south-central Appalachians... A complex, multi-episode severe scenario is apparent, still bearing some important mesoscale uncertainties. However, probabilities supporting an "enhanced" category appear solidly warranted over most of the original area that has not been too convectively processed, and mesoscale foci may yield denser swaths of severe (wind in particular) within that remaining broad corridor. An ongoing severe MCS, with embedded supercells and bowing segments and a history of several overnight tornadoes in the Ozarks, will continue to pose a threat for all severe hazards (including tornadoes) for at least the next several hours past midday. This threat should persist as activity exits the Ozarks, crosses the adjoining Mississippi Valley, and moves into parts of the lower Ohio Valley vicinity. Some northward expansion toward/past the warm front is possible over the Ohio Valley. This activity should only gradually outpace the most favorable buoyancy as it approaches the Appalachians, and may still have a severe threat across the higher terrain. Confidence in its persistence is heightened by the presence of at least one MCV over the eastern Ozarks, which should enhance ascent and lower/middle-tropospheric vertical wind profiles/shear on the mesoscale. Organization of these thunderstorms should continue to take advantage of forced lift with cold pools, as well as lift from internal rotational dynamics of supercells and bookend vortices, to overcome modest MLCINH this morning through midday. Inflow air will contain rich low-level moisture (surface dewpoints commonly in the upper 60s to low 70s F, locally higher), and will be diurnally destabilizing from heating and warm advection near and south of the warm front. For near-term guidance, see SPC Tornado Watch 314 and related mesoscale discussions. Details of subsequent round(s) of convection still remain to be resolved, based substantially on the character and extent of poleward return of the outflow boundary from the leading activity. As such, further modifications (some substantial) may be needed to especially western parts of the outlook areas today. One zone of relatively maximized deep ascent appears to be associated with passage of the convectively reinforced prefrontal boundary over parts of MO and southeastern KS, initially penetrating outflow air from the leading activity. This regime should continue to benefit from large-scale DCVA/ascent aloft, related to the shortwave trough and closely associated convectively induced/enhanced vorticity fields. Activity interacting with the outflow boundary's theta-e gradient, backed near-surface winds, and maximized mesoscale vorticity in low levels should pose the greatest potential for tornadoes. However the afternoon/evening tornado risk is not yet focused tightly, due to uncertainties regarding the evolution of a boundary still being produced at this time. The general large-scale ascent, along with direct frontal lift and heating of a very moist airmass in the warm sector, also should support at least isolated to widely scattered, near-frontal convective development farther south across parts of AR and eastern OK, southwest of the outflow boundary. This activity, including supercells, should occur in an environment of stronger EML-related MLCINH for much of the day, but also, steep midlevel lapse rates, optimal moisture (surface dewpoints commonly low-mid 70s F), and weakening capping with time this afternoon. Despite some veering of near-surface winds, which may limit convergence, any activity that develops still will occur in an environment of 50-65-kt effective- shear magnitudes, and peak local MLCAPE commonly in the 3500-4500 J/kg range. Forecast hodographs and 2D hail models suggest very large hail of 3+ inches in diameter may occur with any sustained, relatively discrete storm this afternoon into early evening. Additional development is possible farther east in the warm sector, near and east of the Mississippi River and south of the MCS outflow, off the eastern rim of the EML where MLCINH is weaker but moisture and heating are strong. ..Edwards/Goss.. 05/26/2024 Read more

WW 0314 Status Updates
STATUS REPORT ON WW 314 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NW HRO TO 25 NE HRO TO 35 WNW TBN AND 25 WSW HRO TO 25 E FLP TO 25 SE UNO TO 35 W POF TO 40 SW FAM TO 35 WSW FAM TO 20 NNE FAM. ..GOSS..05/26/24 ATTN...WFO...LZK...MEG...PAH...LSX...SGF... STATUS REPORT FOR WT 314 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC005-021-049-055-065-075-089-101-121-129-135-137-261240- AR . ARKANSAS COUNTIES INCLUDED ARE BAXTER CLAY FULTON GREENE IZARD LAWRENCE MARION NEWTON RANDOLPH SEARCY SHARP STONE ILC003-047-055-059-065-069-077-081-087-127-145-151-153-157-165- 181-185-191-193-199-261240- IL . ILLINOIS COUNTIES INCLUDED ARE ALEXANDER EDWARDS FRANKLIN GALLATIN HAMILTON HARDIN JACKSON JEFFERSON JOHNSON MASSAC PERRY POPE PULASKI RANDOLPH SALINE UNION WABASH WAYNE WHITE WILLIAMSON Read more

WW 0314 Status Updates
STATUS REPORT ON WW 314 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NW HRO TO 25 NE HRO TO 35 WNW TBN AND 25 WSW HRO TO 25 E FLP TO 25 SE UNO TO 35 W POF TO 40 SW FAM TO 35 WSW FAM TO 20 NNE FAM. ..GOSS..05/26/24 ATTN...WFO...LZK...MEG...PAH...LSX...SGF... STATUS REPORT FOR WT 314 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC005-021-049-055-065-075-089-101-121-129-135-137-261240- AR . ARKANSAS COUNTIES INCLUDED ARE BAXTER CLAY FULTON GREENE IZARD LAWRENCE MARION NEWTON RANDOLPH SEARCY SHARP STONE ILC003-047-055-059-065-069-077-081-087-127-145-151-153-157-165- 181-185-191-193-199-261240- IL . ILLINOIS COUNTIES INCLUDED ARE ALEXANDER EDWARDS FRANKLIN GALLATIN HAMILTON HARDIN JACKSON JEFFERSON JOHNSON MASSAC PERRY POPE PULASKI RANDOLPH SALINE UNION WABASH WAYNE WHITE WILLIAMSON Read more

MD 0970 CONCERNING TORNADO WATCH 311...314... FOR SOUTHERN MISSOURI AND NORTHERN ARKANSAS
Mesoscale Discussion 0970 NWS Storm Prediction Center Norman OK 0412 AM CDT Sun May 26 2024 Areas affected...southern Missouri and northern Arkansas Concerning...Tornado Watch 311...314... Valid 260912Z - 261045Z The severe weather threat for Tornado Watch 311, 314 continues. SUMMARY...Severe/tornado risk continues across southern Missouri and northern Arkansas. DISCUSSION...Latest radar loop shows complex clustering of severe/supercell storms, including spin-up of several small low-level circulations -- and associated/brief tornadoes -- in the past half hour over southern Missouri. Meanwhile, the two more substantial/long-lived supercells -- one now moving east-southeastward across Stone County Missouri and the other crossing Marion County Arkansas -- both remain capable of producing all-hazards severe weather. The Marion County storm, in particular, appears to have produced a tornado over the past 15 minutes per WSR-88D correlation coefficient. Severe potential will likely continue/spread eastward over the next few hours. Gradually, storms will vacate eastern portions of Tornado Watch 311, and move fully into Tornado Watch 314. However, storms may not fully clear WW 311 prior to its scheduled 10Z expiration -- possibly requiring an EXT to cover the ongoing risk. ..Goss.. 05/26/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...MEG...LSX...LZK...SGF...TSA... LAT...LON 35999286 36369401 36589430 37609396 37799303 37849139 37329021 36039066 35999286 Read more

WW 0314 Status Updates
STATUS REPORT ON WW 314 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NW HRO TO 25 NE HRO TO 35 WNW TBN. ..GOSS..05/26/24 ATTN...WFO...LZK...MEG...PAH...LSX...SGF... STATUS REPORT FOR WT 314 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC005-009-021-049-055-065-075-089-101-121-129-135-137-261140- AR . ARKANSAS COUNTIES INCLUDED ARE BAXTER BOONE CLAY FULTON GREENE IZARD LAWRENCE MARION NEWTON RANDOLPH SEARCY SHARP STONE ILC003-047-055-059-065-069-077-081-087-127-145-151-153-157-165- 181-185-191-193-199-261140- IL . ILLINOIS COUNTIES INCLUDED ARE ALEXANDER EDWARDS FRANKLIN GALLATIN HAMILTON HARDIN JACKSON JEFFERSON JOHNSON MASSAC PERRY POPE PULASKI RANDOLPH SALINE UNION WABASH WAYNE WHITE WILLIAMSON Read more

WW 0313 Status Updates
STATUS REPORT ON WW 313 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SW SJT TO 5 E SJT TO 30 WSW BWD. ..GOSS..05/26/24 ATTN...WFO...SJT...MAF... STATUS REPORT FOR WS 313 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TXC049-095-105-413-451-261040- TX . TEXAS COUNTIES INCLUDED ARE BROWN CONCHO CROCKETT SCHLEICHER TOM GREEN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0313 Status Updates
STATUS REPORT ON WW 313 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SW SJT TO 5 E SJT TO 30 WSW BWD. ..GOSS..05/26/24 ATTN...WFO...SJT...MAF... STATUS REPORT FOR WS 313 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TXC049-095-105-413-451-261040- TX . TEXAS COUNTIES INCLUDED ARE BROWN CONCHO CROCKETT SCHLEICHER TOM GREEN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0313 Status Updates
STATUS REPORT ON WW 313 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SW SJT TO 5 E SJT TO 30 WSW BWD. ..GOSS..05/26/24 ATTN...WFO...SJT...MAF... STATUS REPORT FOR WS 313 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TXC049-095-105-413-451-261040- TX . TEXAS COUNTIES INCLUDED ARE BROWN CONCHO CROCKETT SCHLEICHER TOM GREEN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0313 Status Updates
STATUS REPORT ON WW 313 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SW SJT TO 5 E SJT TO 30 WSW BWD. ..GOSS..05/26/24 ATTN...WFO...SJT...MAF... STATUS REPORT FOR WS 313 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TXC049-095-105-413-451-261040- TX . TEXAS COUNTIES INCLUDED ARE BROWN CONCHO CROCKETT SCHLEICHER TOM GREEN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0313 Status Updates
STATUS REPORT ON WW 313 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SW SJT TO 5 E SJT TO 30 WSW BWD. ..GOSS..05/26/24 ATTN...WFO...SJT...MAF... STATUS REPORT FOR WS 313 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TXC049-095-105-413-451-261040- TX . TEXAS COUNTIES INCLUDED ARE BROWN CONCHO CROCKETT SCHLEICHER TOM GREEN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 313 SEVERE TSTM TX 260600Z - 261200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 313 NWS Storm Prediction Center Norman OK 100 AM CDT Sun May 26 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of West-central Texas * Effective this Sunday morning from 100 AM until 700 AM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 3 inches in diameter possible Isolated damaging wind gusts to 60 mph possible SUMMARY...Thunderstorms have developed along a dryline over the eastern Permian Basin area, with additional towers evident to the south in satellite imagery. The environment supports significant (2+ inch) damaging hail with any storms that can persist, as convection shifts eastward toward the Concho Valley region. Though capping strengthens eastward from the dryline, isolated severe gusts also may occur. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 40 miles southwest of San Angelo TX to 55 miles north northeast of San Angelo TX. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 309...WW 310...WW 311...WW 312... AVIATION...A few severe thunderstorms with hail surface and aloft to 3 inches. Extreme turbulence and surface wind gusts to 50 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 27025. ...Edwards Read more

MD 0969 CONCERNING SEVERE THUNDERSTORM WATCH 313... FOR CENTRAL TEXAS
Mesoscale Discussion 0969 NWS Storm Prediction Center Norman OK 0253 AM CDT Sun May 26 2024 Areas affected...central Texas Concerning...Severe Thunderstorm Watch 313... Valid 260753Z - 261000Z The severe weather threat for Severe Thunderstorm Watch 313 continues. SUMMARY...Risk for large hail, and a damaging gust or two, continues across the Concho Valley vicinity of central Texas. DISCUSSION...A band of strong/locally severe storms continues moving across west-central and central Texas at this time, within an rather narrow corridor of maximized CAPE extending from roughly SPS to DRT. While severe risk should continue with this convection over the next 1 to 2 hours, it appears that risk gradually decreases with eastward extent, east of the zone of greater instability. CAM output generally confirms a weakening of the convection with time as it shifts eastward. As such, the leading edge of the stronger convection -- now moving into Coleman County -- may begin to diminish in the next 1 to 2 hours as storms cross the Brown County vicinity and reach Comanche/Mills/Hamilton Counties. Meanwhile, severe potential should continue locally across the remaining portions of WW 313. ..Goss.. 05/26/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...SJT...MAF... LAT...LON 31130184 32119961 32409921 32469837 31159854 30820053 31130184 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 26 2024 Valid 291200Z - 031200Z ...DISCUSSION... In general, medium-range models indicate that larger-scale mid/upper troughing will slowly progress eastward across and offshore of the Atlantic Seaboard through the middle to latter portion of the coming work week. As this occurs, flow across the northern mid-latitudes of the Pacific into North America may trend less amplified, while flow across the southern mid- and subtropical latitudes trends a bit more amplified. It appears that this may include modest mid-level troughing approaching the California and Baja coast next weekend, upstream of building large-scale ridging across the southern Rockies through the middle and lower Mississippi Valley. Shorter wavelength developments are substantially more unclear throughout the period due to sizable model spread. Beneath this regime, moderate to strong potential instability, associated with seasonably moist boundary-layer air beneath steep lower/mid-tropospheric lapse rates, may mostly remain confined to the higher plains to the lee of the Front Range southward into the Pecos Valley. As mid-level heights fall to the south of the initially prominent trough slowly progressing to the east of the northern Rockies late this week, it is possible that storms developing in the late afternoons off the higher terrain could evolve into clusters posing at least some severe weather threat across the adjacent plains. However, due to generally low predictability, severe weather probabilities are being maintained at less than 15 percent. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 26 2024 Valid 291200Z - 031200Z ...DISCUSSION... In general, medium-range models indicate that larger-scale mid/upper troughing will slowly progress eastward across and offshore of the Atlantic Seaboard through the middle to latter portion of the coming work week. As this occurs, flow across the northern mid-latitudes of the Pacific into North America may trend less amplified, while flow across the southern mid- and subtropical latitudes trends a bit more amplified. It appears that this may include modest mid-level troughing approaching the California and Baja coast next weekend, upstream of building large-scale ridging across the southern Rockies through the middle and lower Mississippi Valley. Shorter wavelength developments are substantially more unclear throughout the period due to sizable model spread. Beneath this regime, moderate to strong potential instability, associated with seasonably moist boundary-layer air beneath steep lower/mid-tropospheric lapse rates, may mostly remain confined to the higher plains to the lee of the Front Range southward into the Pecos Valley. As mid-level heights fall to the south of the initially prominent trough slowly progressing to the east of the northern Rockies late this week, it is possible that storms developing in the late afternoons off the higher terrain could evolve into clusters posing at least some severe weather threat across the adjacent plains. However, due to generally low predictability, severe weather probabilities are being maintained at less than 15 percent. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 26 2024 Valid 291200Z - 031200Z ...DISCUSSION... In general, medium-range models indicate that larger-scale mid/upper troughing will slowly progress eastward across and offshore of the Atlantic Seaboard through the middle to latter portion of the coming work week. As this occurs, flow across the northern mid-latitudes of the Pacific into North America may trend less amplified, while flow across the southern mid- and subtropical latitudes trends a bit more amplified. It appears that this may include modest mid-level troughing approaching the California and Baja coast next weekend, upstream of building large-scale ridging across the southern Rockies through the middle and lower Mississippi Valley. Shorter wavelength developments are substantially more unclear throughout the period due to sizable model spread. Beneath this regime, moderate to strong potential instability, associated with seasonably moist boundary-layer air beneath steep lower/mid-tropospheric lapse rates, may mostly remain confined to the higher plains to the lee of the Front Range southward into the Pecos Valley. As mid-level heights fall to the south of the initially prominent trough slowly progressing to the east of the northern Rockies late this week, it is possible that storms developing in the late afternoons off the higher terrain could evolve into clusters posing at least some severe weather threat across the adjacent plains. However, due to generally low predictability, severe weather probabilities are being maintained at less than 15 percent. Read more