Severe Storms

No watches are valid as of Wed Aug 28 20:53:01 UTC 2024.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Wed Aug 28 2024 Valid 282000Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ALONG THE NORTH DAKOTA SOUTH DAKOTA BORDER... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND THE OHIO VALLEY INTO THE MID ATLANTIC... ...SUMMARY... Severe thunderstorms are expected across parts of the Dakotas and from the Ohio Valley to the Mid-Atlantic Coast this afternoon through this evening. ...20z Update... No substantial changes have been made to the prior outlook. Storm coverage should gradually increase over parts of the OH Valley and Mid Atlantic through this afternoon. Damaging gusts will be possible with the stronger clusters of storms, potentially focused from eastern OH into WV and PA. To the west, supercell development is expected near the surface low and along the trialing surface trough/wind shift across western SD/ND late this afternoon. Moderate mid-level ascent overspreading a warming and moistening air mass across the Dakotas will allow for rapid storm development and intensification as CINH is removed. Large hail remains the primary threat, along with damaging gusts, given strong buoyancy and robust supercell wind profiles. However, strong low-level turning may support a risk for a couple of tornadoes with the more discrete supercells, especially near the warm front. Most short-term guidance does show gradual upscale growth this evening and into the early overnight period across the eastern Dakotas. Should this occur, the risk for damaging winds may increase with the greater organized/persistent clusters before they move into more stable air across parts of western MN. See the prior discussion for additional information. ..Lyons.. 08/28/2024 .PREV DISCUSSION... /ISSUED 1136 AM CDT Wed Aug 28 2024/ ...Dakotas... Have upgraded portions of south-central North Dakota/north-central South Dakota to a categorical Enhanced Risk for what should be a relatively greater likelihood and concentration of severe storms late this afternoon through early/mid-evening. A prominent upper-level trough centered over western Montana and southern Alberta will continue generally eastward over the Canadian Prairies and toward the northern High Plains, with a trough-preceding/basal upper-level jet resulting in considerably strengthening southwesterly winds aloft by peak heating into tonight. This will be atop an increasingly moist boundary layer (dewpoints increasing through the 60s F) ahead of a surface low across South Dakota and a front extending northward into North Dakota. Thunderstorms should develop near the front by late afternoon/early evening, perhaps initially across North Dakota where overall forcing will be greater, and subsequently southward into South Dakota where richer low-level moisture and greater buoyancy will reside. Given steep lapse rates and the reservoir of instability, these initial storms should be supercells capable of very large hail amidst strengthening flow aloft. Large to very large hail and severe wind gusts will be the most common hazards, although a tornado risk may also exist particularly across north-central South Dakota/far south-central North Dakota near the surface low/warm front-related triple point where moisture/low-level SRH will be maximized. Over time, relatively weak mid-level flow may encourage a transition to messier, quasi-linear modes with embedded LEWP/bow formations for a few hours. Activity should weaken overnight as it moves into stabilizing boundary-layer air, though a 45-55-kt low-level jet may encourage persistence of a cluster or two tonight into the eastern Dakotas. ...Midwest/Ohio Valley to Mid-Atlantic States... Widely scattered to scattered thunderstorms will pose a risk for damaging winds particularly mid/late afternoon through early/mid-evening regionally. Some hail may also occur on a more marginal and isolated basis. This severe risk will primarily span parts of Indiana/Ohio eastward to the coastal Mid-Atlantic/Delmarva vicinity, although the overall extent and magnitude of today's risk is still a bit uncertain. The boundary layer will not be overly moist by late-summer standards, particularly across the middle Ohio River Valley, but a relatively richer moist axis (through the lowest 2-3 km AGL) extends this morning from the upper Ohio Valley eastward toward the coastal Mid-Atlantic/Northeast. The boundary layer will also not be overly unstable later today, with severe-adequate MLCAPE generally limited to 2000 J/kg MLCAPE. Aside from differential heating related to last night's convection across the Midwest, several impetuses for thunderstorm development to the south of the primary Great Lakes front may include the eastward transitions of MCVs across southeast Lower Michigan and north-central Illinois, which should be influential into the Lake Ontario/New York/northern Pennsylvania and lower/middle Ohio Valley vicinities, respectively, later this afternoon and evening. Effective shear will tend to be limited to 20-25 kt, but slowly-increasing-with-height deep-layer westerlies will support multicell-related damaging wind/some hail potential as low-level lapse rates steepen and the boundary layer moderately destabilizes this afternoon. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Wed Aug 28 2024 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER GREAT LAKES AND MIDWEST... ...SUMMARY... Strong/locally severe storms will be posible from Lakes Huron and Erie southwestward into the Midwest Friday. ...Synopsis... An upper-level trough will continue moving slowly eastward out of the north-central U.S. across the Great Lakes and Midwest on Friday, with the more vigorous portion of the trough expected to eject northeastward across Ontario into the Hudson Bay region. At the surface, a cold front is forecast to continue eastward across the Great Lakes, southeastward across the Midwest, and southward across the Plains. By the end of the period, the front should extend from the Lower Great Lakes west-southwestward across the Ohio Valley, and into Oklahoma and northern Texas. ...Lower Michigan/northern Ohio/northwestern Pennsylvania across the Midwest... Destabilization is expected ahead of the cold front, with moderate/pockets of strong MLCAPE by afternoon. With minimal CINH, thunderstorm development is likely from lower MI southwest to IL. Although the stronger deep-layer shear will lag towards the cool side of the front, modest westerly mid-level flow of 20-25 kts will favor loosely-organized storms that should tend to cluster over time. Strong/isolated damaging gusts and perhaps severe hail will be possible. ..Bunting.. 08/28/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Wed Aug 28 2024 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF MINNESOTA...WESTERN WISCONSIN AND NORTHERN IOWA... ...SUMMARY... Severe thunderstorms are possible on Thursday from portions of the Upper/Middle Mississippi Valley to the central Plains. A few severe storms also will be possible over portions of the mid-Atlantic region. ...Synopsis... A weak upper-level short-wave trough will shift east across the Northeast on Thursday, as a much stronger trough/low will continue to advance into/across the north-central states. At the surface, a cold front is forecast to sag southward across the Mid-Atlantic region in lee of the Appalachians, while a more prominent cold front shifts eastward/southeastward across the central and northern Plains. ...Mid and Upper Mississippi Valley area to the central Plains... Large scale ascent with the upper low/trough will increase in the vicinity of the eastward-advancing cold front over MN/northern IA, augmented by the right-entrance region of a 250-mb jet lifting north during the day. Substantial instability should be in place by afternoon, with afternoon MLCAPE in excess of 3000 J/kg expected. Strengthening mid-level flow with the approach of the upper trough will contribute to deep-layer shear of 35-45 kts, supporting organized storms including the potential for supercell structures. Thunderstorms should increase in coverage through the afternoon and evening, becoming more linear with time along the cold front. Damaging winds and large hail will be the primary severe hazards, with the severe risk continuing into the evening hours. Some tornado risk may also develop with embedded QLCS circulations as low-level shear appears supportive, especially within the Slight Risk area. Both instability and shear will diminish with southward extent across eastern NE/northern KS, however afternoon thunderstorm development is expected along the front within a largely uncapped environment. Isolated damaging winds will be the primary risk as strong boundary-layer heating will steepen low-level lapse rates, and storms begin to cluster during the late afternoon/evening. Instances of large hail will also be possible. ...Mid-Atlantic Region... A southward-moving cold front will move across the mid-Atlantic in the lee of the Appalachians Thursday within a moderately unstable though weakly sheared environment. With minimal afternoon CINH, thunderstorms should develop over the higher terrain and along the front and tend to cluster with time. This will result in a risk for damaging gusts, and perhaps hail with the stronger updrafts. ..Bunting.. 08/28/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Wed Aug 28 2024 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF MINNESOTA...WESTERN WISCONSIN AND NORTHERN IOWA... ...SUMMARY... Severe thunderstorms are possible on Thursday from portions of the Upper/Middle Mississippi Valley to the central Plains. A few severe storms also will be possible over portions of the mid-Atlantic region. ...Synopsis... A weak upper-level short-wave trough will shift east across the Northeast on Thursday, as a much stronger trough/low will continue to advance into/across the north-central states. At the surface, a cold front is forecast to sag southward across the Mid-Atlantic region in lee of the Appalachians, while a more prominent cold front shifts eastward/southeastward across the central and northern Plains. ...Mid and Upper Mississippi Valley area to the central Plains... Large scale ascent with the upper low/trough will increase in the vicinity of the eastward-advancing cold front over MN/northern IA, augmented by the right-entrance region of a 250-mb jet lifting north during the day. Substantial instability should be in place by afternoon, with afternoon MLCAPE in excess of 3000 J/kg expected. Strengthening mid-level flow with the approach of the upper trough will contribute to deep-layer shear of 35-45 kts, supporting organized storms including the potential for supercell structures. Thunderstorms should increase in coverage through the afternoon and evening, becoming more linear with time along the cold front. Damaging winds and large hail will be the primary severe hazards, with the severe risk continuing into the evening hours. Some tornado risk may also develop with embedded QLCS circulations as low-level shear appears supportive, especially within the Slight Risk area. Both instability and shear will diminish with southward extent across eastern NE/northern KS, however afternoon thunderstorm development is expected along the front within a largely uncapped environment. Isolated damaging winds will be the primary risk as strong boundary-layer heating will steepen low-level lapse rates, and storms begin to cluster during the late afternoon/evening. Instances of large hail will also be possible. ...Mid-Atlantic Region... A southward-moving cold front will move across the mid-Atlantic in the lee of the Appalachians Thursday within a moderately unstable though weakly sheared environment. With minimal afternoon CINH, thunderstorms should develop over the higher terrain and along the front and tend to cluster with time. This will result in a risk for damaging gusts, and perhaps hail with the stronger updrafts. ..Bunting.. 08/28/2024 Read more