Severe Storms

WW 0597 Status Updates
STATUS REPORT ON WW 597 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..08/17/25 ATTN...WFO...BIS...ABR...UNR... STATUS REPORT FOR WS 597 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC021-029-045-047-051-085-170640- ND . NORTH DAKOTA COUNTIES INCLUDED ARE DICKEY EMMONS LAMOURE LOGAN MCINTOSH SIOUX SDC013-017-019-021-031-033-041-045-049-055-059-063-065-069-071- 075-081-085-089-093-103-105-107-115-117-119-129-137-170640- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO BUTTE CAMPBELL CORSON CUSTER DEWEY EDMUNDS FAULK HAAKON HAND HARDING HUGHES HYDE JACKSON JONES LAWRENCE LYMAN MCPHERSON MEADE PENNINGTON PERKINS POTTER SPINK STANLEY SULLY WALWORTH ZIEBACH Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CDT Sun Aug 17 2025 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF THE NORTHERN ROCKIES...PORTIONS OF THE MIDDLE MISSOURI VALLEY AND ADJACENT GREAT PLAINS...AND PARTS OF THE NORTHERN MID ATLANTIC... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for strong to severe wind gusts across parts of the northern Rockies into middle Missouri Valley late today into tonight. Strong thunderstorm development accompanied by potentially damaging wind gusts is also possible across parts of the northern Mid Atlantic late this afternoon and evening. ...Discussion... Large-scale mid-level troughing is forecast to undergo further amplification across southeastern Quebec through portions of northern New England and the Canadian Maritimes during this period. As this occurs, a notable cold front is forecast to advance southward across much of the Northeast, Mid Atlantic and Ohio Valley by 12Z Monday, beneath the northeastern periphery of large-scale mid/upper ridging encompassing much of the interior U.S and southern Canadian Provinces. The western flank of the intrusion of cooler/drier boundary layer air is likely to stall across the lower Ohio Valley into Upper Midwest vicinity, but a more modest southward cool surge is also forecast across the northern high plains, in the wake of weak mid-level troughing slowly migrating within the larger-scale ridging across and east of the Dakotas/Nebraska vicinity. A number of other smaller-scale perturbations are forecast to progress through modest/weak cyclonic to anticyclonic flow inland of the Pacific coast through the Rockies, downstream of a significant, amplifying large-scale trough offshore of the British Columbia and Pacific Northwest coast. ...Parts of the mid Missouri Valley into Midwest... Models indicate unsaturated lower/mid-tropospheric thermodynamic profiles with steep lapse rates, aided by continuing eastward advection of elevated mixed-layer air, will be maintained across much of the South Dakota and Nebraska vicinity through this period. Beneath this regime, seasonably high boundary-layer moisture content will continue to contribute to the development of moderate to large potential instability with insolation, along and south of an initially stalled frontal zone across southern Minnesota/southern Iowa through southern South Dakota. Residual convection with a possible MCV may be in the process of spreading well to the cool side of this boundary, across and northeast of the eastern Dakotas at 12Z this morning. There appears at least some potential for renewed convective development along the southern flank of this activity, in closer proximity to the frontal zone and destabilizing boundary-layer (roughly focused near the Minnesota/Iowa border), aided by forcing for ascent associated with warm advection during the day. Otherwise, stronger thunderstorm development may await forcing associated with a perturbation within the southern periphery of the weak mid-level troughing forecast to overspread the (roughly) South Dakota/Nebraska border vicinity by early this evening. There is considerable spread evident among the models concerning these and subsequent developments, with the NAM depicting the evolution of a notable convective perturbation. Other output is less pronounced, but, despite generally weak wind fields and shear, forecast thermodynamic profiles appear potentially conducive to the evolution of an upscale growing and organizing cluster with the potential to produce strong to severe wind gusts this evening and overnight. ...Montana... Downstream of the northeastern Pacific mid-level trough, at least broadly difluent upper flow, perhaps enhanced ahead of a subtle mid-level wave crossing the northern Rockies, may aid the development of thunderstorm activity off the mountains of south central into southeastern Montana late this afternoon and evening. Forecast soundings east of the higher terrain appear to include sufficient shear and favorable thermodynamic profiles for the evolution of a small east-southeastward propagating cluster with potential to produce severe wind and hail. ...Northern Mid Atlantic... Seasonably high moisture content and boundary-layer heating focused along a pre-frontal surface trough may contribute to an environment conducive to a few strong downbursts, aided by heavy precipitation loading. It is possible that forcing for ascent associated with a remnant convectively generated perturbation may contribute to a clustering of thunderstorm activity along this corridor, from parts of northern Virginia through southeastern Pennsylvania and New Jersey, late this afternoon or evening. ..Kerr/Lyons.. 08/17/2025 Read more

MD 1970 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR FAR EASTERN WYOMING...WESTERN INTO CENTRAL SOUTH DAKOTA...EXTREME SOUTHEAST MONTANA...AND SOUTHERN NORTH DAKOTA
Mesoscale Discussion 1970 NWS Storm Prediction Center Norman OK 1023 PM CDT Sat Aug 16 2025 Areas affected...far eastern Wyoming...western into central South Dakota...extreme southeast Montana...and southern North Dakota Concerning...Severe potential...Watch likely Valid 170323Z - 170530Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms continue to gradually strengthen and increase in coverage. An increasing potential for damaging thunderstorm winds will likely warrant the need for a severe thunderstorm watch this evening/overnight. DISCUSSION...Thunderstorm organization and intensity continues to gradually increase this evening across northeast Wyoming and far western South Dakota. This is likely in response to increasing large-scale ascent as an upstream short-wave trough approaches the region. The airmass along and immediately ahead of the shortwave remains strongly unstable (MUCAPE up to 3000 J/kg) and sufficiently sheared (ESHR around 35 knots) to support severe thunderstorms. Current expectation is that these thunderstorms will continue to intensify and organize as they move into the more unstable environment and the nocturnal low-level jet strengthens. The primary severe threat should be damaging thunderstorm winds driven by internal MCS dynamics. That said, this evening's 00Z UNR (Rapid City, SD) sounding sampled sufficiently steep mid-level lapse rates to support at least some potential for large hail. Trends will continue to be monitored, but it is increasingly likely that a severe thunderstorm watch will be needed in the next 1-2 hours. ..Marsh/Smith.. 08/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR...CYS...BYZ... LAT...LON 43650119 43030270 43170406 43910496 44810497 45790423 46750148 46680021 45889966 44979935 44219963 43650119 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0597 Status Updates
STATUS FOR WATCH 0597 HAS NOT BEEN ISSUED YET Read more

MD 1969 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHEASTERN IOWA SOUTHWEST WISCONSIN AND NORTHERN ILLINOIS
Mesoscale Discussion 1969 NWS Storm Prediction Center Norman OK 0806 PM CDT Sat Aug 16 2025 Areas affected...portions of northeastern Iowa southwest Wisconsin and northern Illinois Concerning...Severe potential...Watch unlikely Valid 170106Z - 170230Z Probability of Watch Issuance...20 percent SUMMARY...Storms forming along a trailing outflow boundary may remain capable of sporadic hail and occasional strong wind gusts for a few hours this evening. DISCUSSION...As of 01 UTC, regional radar imagery showed several clusters of storms had redeveloped along a trailing outflow boundary from prior convection across portions of northern IL, eastern IA and southwestern WI. Several of these storms have shown periods of higher intensity with reports of hail over the last hour. This threat should continue with occasional hail or damaging gusts as the air mass along and south of the outflow remains very unstable with 4000-5000 j/kg of MUCAPE. Vertical shear, while not overly strong (25-35 kt 0-6km agl), is sufficient for a mixed convective mode of multicell clusters and transient supercell structures near the boundary. The tendency for developing storms to move eastward toward weaker buoyancy suggests intensification of individual cells should be relatively brief. Additionally, the strongest vertical shear remains displaced farther north which should keep overall organization limited. A WW is unlikely given the lack of a more focused/sustained severe risk, but occasional hail and a damaging gust are possible. ..Lyons/Smith.. 08/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX... LAT...LON 41308897 41728984 42259068 42849174 43259169 43279015 42868903 42028796 41488801 41278823 41308897 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

MD 1968 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WESTERN SOUTH DAKOTA
Mesoscale Discussion 1968 NWS Storm Prediction Center Norman OK 0636 PM CDT Sat Aug 16 2025 Areas affected...western South Dakota Concerning...Severe potential...Watch possible Valid 162336Z - 170130Z Probability of Watch Issuance...40 percent SUMMARY...Severe thunderstorm potential will increase this afternoon into the evening. Large hail may be an initial concern, but the primary severe threat should be damaging winds. DISCUSSION...Strong heating of a moist airmass across western South Dakota has resulted in a strongly unstable environment with MUCAPE in excess of 3000 J/kg in areas. Within this environment, thunderstorms are gradually increasing in coverage in response to strengthening large-scale ascent ahead of another shortwave trough moving around the periphery of the southern Plains ridge. Continued southeast-to-east surface winds beneath westerly flow aloft will maintain a sheared (ESHR around 35-40 knots) environment across the region. The combination of a strongly unstable and sheared environment should result in a gradual increase in thunderstorm intensity late this afternoon into the evening. The primary threat will be strong, damaging thunderstorm winds as thunderstorm coverage increases later this evening and thunderstorm outflows congeal ahead of the aforementioned trough. Isolated large to perhaps significant hail may occur with the strongest, more discrete thunderstorms. The need for a severe thunderstorm watch this evening remains somewhat unclear, but may increase this evening into the overnight hours. The most likely onset of more widespread severe potential should be after 9 PM MDT. However, conditions will be monitored through the evening in the event coverage and intensity begins to increase. ..Marsh/Smith.. 08/16/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...LBF...UNR...BYZ... LAT...LON 42800197 43310375 44510434 45780402 46130352 45920163 45520078 44390047 43250061 42800197 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more