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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Aug 24 2024 Valid 242000Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FOUR CORNERS INTO THE CENTRAL HIGH PLAINS...ACROSS NORTHEAST MONTANA AND FAR NORTHWEST NORTH DAKOTA...AND WESTERN OKLAHOMA... ...SUMMARY... Strong to locally severe storms are possible today from the Four Corners region northeastward into the central High Plains, over northeast Montana/northwest North Dakota and also across western Oklahoma. ...20z Update... The primary change for this update was the removal of the Marginal risk area across southern Missouri/northern Arkansas. The ongoing MCS along the MO/AR border has shown a steady weakening trend over the past few hours in early all convective metrics (IR cloud top temperatures, lightning counts, maximum reflectivity, etc...). A sporadic strong updraft pulse or two will remain possible across northern AR given MLCAPE values between 1000-22000 J/kg, but the overall weakening trend is expected to continue as the MCS migrates closer to the center of an upper anti-cyclone where deep-layer wind shear is negligible. Elsewhere, the forecast remains on track with no changes required. See the previous discussion (below) for additional details. ..Moore.. 08/24/2024 .PREV DISCUSSION... /ISSUED 1128 AM CDT Sat Aug 24 2024/ ...Northeast Montana/northwest North Dakota... Have introduced severe hail/wind probabilities for the potential of isolated severe thunderstorm development beginning potentially as early as late afternoon across northeast Montana, but more likely this evening across the region. This development is possible along/behind a surface wave and eastward-moving front, where moderate buoyancy will coincide with strong shear through the cloud-bearing layer. ...Four Corners to Central High Plains... Widely scattered to scattered thunderstorms are expected by mid/late afternoon. Activity should move northward to northeastward over this corridor, with isolated severe gusts being the main concern, and hail near severe limits also possible over the High Plains. Effective shear will be modest (generally 30 kt or less), but enough cloud-layer shear for a few organized multicell storms, with a well-mixed sub-cloud layer supportive of strong/locally severe wind gusts. ...Southern Missouri/northern Arkansas... A linear convective cluster will continue to progress southward today. Deep-layer/low-level shear will remain weak, with the cluster tending to remain elevated to the east of the main reservoir of surface-based buoyancy and mid-level lapse rates. While some strong gusts and/or sub-severe hail could occur, the overall severe potential should remain isolated and relatively marginal in nature. ...Western/northern Oklahoma.... Isolated to widely scattered thunderstorms are possible by late afternoon through around sunset, with locally strong-severe microbursts possible. A surface moist/buoyancy axis will persist under and near the mid/upper high, with an effective dryline to its west across northwest Texas to northwest Oklahoma. Enough moisture should be present to support a minimally capped, deep, hot, well-mixed boundary layer with around 250-1000 J/kg MLCAPE and DCAPE values of 1000-2000 J/kg. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Aug 24 2024 Valid 242000Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FOUR CORNERS INTO THE CENTRAL HIGH PLAINS...ACROSS NORTHEAST MONTANA AND FAR NORTHWEST NORTH DAKOTA...AND WESTERN OKLAHOMA... ...SUMMARY... Strong to locally severe storms are possible today from the Four Corners region northeastward into the central High Plains, over northeast Montana/northwest North Dakota and also across western Oklahoma. ...20z Update... The primary change for this update was the removal of the Marginal risk area across southern Missouri/northern Arkansas. The ongoing MCS along the MO/AR border has shown a steady weakening trend over the past few hours in early all convective metrics (IR cloud top temperatures, lightning counts, maximum reflectivity, etc...). A sporadic strong updraft pulse or two will remain possible across northern AR given MLCAPE values between 1000-22000 J/kg, but the overall weakening trend is expected to continue as the MCS migrates closer to the center of an upper anti-cyclone where deep-layer wind shear is negligible. Elsewhere, the forecast remains on track with no changes required. See the previous discussion (below) for additional details. ..Moore.. 08/24/2024 .PREV DISCUSSION... /ISSUED 1128 AM CDT Sat Aug 24 2024/ ...Northeast Montana/northwest North Dakota... Have introduced severe hail/wind probabilities for the potential of isolated severe thunderstorm development beginning potentially as early as late afternoon across northeast Montana, but more likely this evening across the region. This development is possible along/behind a surface wave and eastward-moving front, where moderate buoyancy will coincide with strong shear through the cloud-bearing layer. ...Four Corners to Central High Plains... Widely scattered to scattered thunderstorms are expected by mid/late afternoon. Activity should move northward to northeastward over this corridor, with isolated severe gusts being the main concern, and hail near severe limits also possible over the High Plains. Effective shear will be modest (generally 30 kt or less), but enough cloud-layer shear for a few organized multicell storms, with a well-mixed sub-cloud layer supportive of strong/locally severe wind gusts. ...Southern Missouri/northern Arkansas... A linear convective cluster will continue to progress southward today. Deep-layer/low-level shear will remain weak, with the cluster tending to remain elevated to the east of the main reservoir of surface-based buoyancy and mid-level lapse rates. While some strong gusts and/or sub-severe hail could occur, the overall severe potential should remain isolated and relatively marginal in nature. ...Western/northern Oklahoma.... Isolated to widely scattered thunderstorms are possible by late afternoon through around sunset, with locally strong-severe microbursts possible. A surface moist/buoyancy axis will persist under and near the mid/upper high, with an effective dryline to its west across northwest Texas to northwest Oklahoma. Enough moisture should be present to support a minimally capped, deep, hot, well-mixed boundary layer with around 250-1000 J/kg MLCAPE and DCAPE values of 1000-2000 J/kg. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Sat Aug 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA AND FAR NORTHERN NEBRASKA INTO PARTS OF MINNESOTA AND WISCONSIN... ...SUMMARY... Severe storms are expected to evolve within a zone extending from the northern High Plains eastward to the Wisconsin vicinity during the afternoon and evening Monday. A few severe storms are also expected across the Northeast and Mid-Atlantic region. ...Northern Plains/Upper Midwest... An upper trough will develop east across the northern Plains on Tuesday. Enhanced southwesterly mid/upper flow (50-60 kt at 500 mb) will overspread a very moist boundary layer (dewpoints in the 70s). A surface cold front will be oriented from northern MN southwest into western SD during the morning, and develop southeast through the period. Convection will develop along the boundary during the day and move across a strongly unstable airmass. Clusters may develop into a fast-moving MCS impacting portions of eastern SD into central/southern MN and parts of WI. Damaging wind swaths and isolated large hail will be possible. The south and east extent of the severe risk is uncertain, and adjustments may be needed in subsequent outlooks as mesoscale details become better resolved. Additional more isolated strong to severe storm may develop in the post-frontal upslope flow regime across NE and parts of the northern High Plains. Strong gusts and hail could accompany this activity. ...Northeast/Mid-Atlantic vicinity... Moderate northwesterly deep-layer flow will persist over the region as an upper trough shifts east over the Atlantic. A seasonally moist airmass will result in pockets of weak instability, supporting isolated to scattered corridors of thunderstorm activity. Steep low-level lapse rates and sufficient vertical shear amid weak instability will support isolated strong gusts and perhaps small hail. ...Central/Southern High Plains vicinity... Severe probabilities have been removed from this area with this update cycle. Forecast guidance varies considerable regarding the degree of destabilization across the region, with ECMWF members showing very little instability, while the more aggressive NAM solutions indicated MUCAPE to near 500 J/kg. Given potential for a large area with little risk, opted to remove this area until confidence increases in which particular areas may see greater thunderstorm coverage. ..Leitman.. 08/24/2024 Read more

000
ABPZ20 KNHC 241732
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sat Aug 24 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Gilma, located well to the west-southwest of the southern tip of
the Baja California peninsula.

Central Portion of the East Pacific (EP92):
Shower and thunderstorm activity remains displaced to the south
and west of an area of low pressure centered several hundred miles
to the southwest of the southern tip of the Baja California
peninsula. Upper-level winds are forecast to become more conducive
for development of the low during the next day or two, and a
tropical depression is expected to form this weekend or early next
week while moving toward the west or west-northwest at around 10
mph.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Beven

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sat Aug 24 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN DAKOTAS INTO NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe storms may develop across the northern Plains area on Sunday, with more isolated severe potential southwestward into the southern Rockies and adjacent High Plains. A couple of strong/marginally severe storms may also occur across the Lower Great Lakes/Upper Ohio Valley vicinity. ...Northern Plains/Upper Midwest... An upper anticyclone will be centered over KS/OK and the Ozark Plateau, with the upper ridge axis oriented northward over the Upper MS Valley on Sunday. Meanwhile, a shortwave upper trough will migrate east across the Canadian Prairies. This will focus an area of modestly enhanced mid/upper southwesterly flow over the Dakotas into the Upper Midwest. At the surface, south/southeasterly flow will maintain a very moist airmass, with dewpoints in the 70s F expected from the eastern Dakotas into IA/MN and vicinity. A plume of steeper midlevel lapse rates will advect northeast, aiding in strong destabilization. However, warm midlevel temps will likely maintain at least weak MLCIN across the region through the afternoon and into the evening as stronger forcing for ascent largely remains north of the international border. As a result, convective coverage during the afternoon is a bit uncertain/conditional. By late afternoon/evening, a surface front is forecast to progress eastward across the Dakotas and into MN through the nighttime hours. This may provide sufficient forcing for isolated thunderstorm development. Given strong instability and sufficient vertical shear for organized updrafts, large hail (especially with initial cellular development) and damaging gusts will be possible. ...Four Corners into WY and adjacent High Plains... An upper trough will lift northeast across the Great Basin on Sunday. Modestly enhanced southwesterly mid/upper flow will overspread the region between the eastern periphery of the trough and the western periphery of the upper ridge to the east. Boundary-layer moisture will remain modest for most of the region, but steep midlevel lapse rates and strong heating will support 500-1000 J/kg MLCAPE. Sporadic downbursts may produce locally severe gusts with this activity. ...Upper Ohio Valley Vicinity... Modest northwesterly mid/upper flow will overspread the region on Sunday on the western periphery of a Northeast upper trough. Latest forecast guidance shows warming midlevel temps/minor height rises during the day. However, a moist airmass will be in place and weak to moderate destabilization is expected. Convective coverage may be fairly low given latest forecast guidance trends. However, any stronger cells that develop may produce locally strong gusts or small hail given favorable shear and elongated/straight forecast hodographs. ..Leitman.. 08/24/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sat Aug 24 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN DAKOTAS INTO NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe storms may develop across the northern Plains area on Sunday, with more isolated severe potential southwestward into the southern Rockies and adjacent High Plains. A couple of strong/marginally severe storms may also occur across the Lower Great Lakes/Upper Ohio Valley vicinity. ...Northern Plains/Upper Midwest... An upper anticyclone will be centered over KS/OK and the Ozark Plateau, with the upper ridge axis oriented northward over the Upper MS Valley on Sunday. Meanwhile, a shortwave upper trough will migrate east across the Canadian Prairies. This will focus an area of modestly enhanced mid/upper southwesterly flow over the Dakotas into the Upper Midwest. At the surface, south/southeasterly flow will maintain a very moist airmass, with dewpoints in the 70s F expected from the eastern Dakotas into IA/MN and vicinity. A plume of steeper midlevel lapse rates will advect northeast, aiding in strong destabilization. However, warm midlevel temps will likely maintain at least weak MLCIN across the region through the afternoon and into the evening as stronger forcing for ascent largely remains north of the international border. As a result, convective coverage during the afternoon is a bit uncertain/conditional. By late afternoon/evening, a surface front is forecast to progress eastward across the Dakotas and into MN through the nighttime hours. This may provide sufficient forcing for isolated thunderstorm development. Given strong instability and sufficient vertical shear for organized updrafts, large hail (especially with initial cellular development) and damaging gusts will be possible. ...Four Corners into WY and adjacent High Plains... An upper trough will lift northeast across the Great Basin on Sunday. Modestly enhanced southwesterly mid/upper flow will overspread the region between the eastern periphery of the trough and the western periphery of the upper ridge to the east. Boundary-layer moisture will remain modest for most of the region, but steep midlevel lapse rates and strong heating will support 500-1000 J/kg MLCAPE. Sporadic downbursts may produce locally severe gusts with this activity. ...Upper Ohio Valley Vicinity... Modest northwesterly mid/upper flow will overspread the region on Sunday on the western periphery of a Northeast upper trough. Latest forecast guidance shows warming midlevel temps/minor height rises during the day. However, a moist airmass will be in place and weak to moderate destabilization is expected. Convective coverage may be fairly low given latest forecast guidance trends. However, any stronger cells that develop may produce locally strong gusts or small hail given favorable shear and elongated/straight forecast hodographs. ..Leitman.. 08/24/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sat Aug 24 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN DAKOTAS INTO NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe storms may develop across the northern Plains area on Sunday, with more isolated severe potential southwestward into the southern Rockies and adjacent High Plains. A couple of strong/marginally severe storms may also occur across the Lower Great Lakes/Upper Ohio Valley vicinity. ...Northern Plains/Upper Midwest... An upper anticyclone will be centered over KS/OK and the Ozark Plateau, with the upper ridge axis oriented northward over the Upper MS Valley on Sunday. Meanwhile, a shortwave upper trough will migrate east across the Canadian Prairies. This will focus an area of modestly enhanced mid/upper southwesterly flow over the Dakotas into the Upper Midwest. At the surface, south/southeasterly flow will maintain a very moist airmass, with dewpoints in the 70s F expected from the eastern Dakotas into IA/MN and vicinity. A plume of steeper midlevel lapse rates will advect northeast, aiding in strong destabilization. However, warm midlevel temps will likely maintain at least weak MLCIN across the region through the afternoon and into the evening as stronger forcing for ascent largely remains north of the international border. As a result, convective coverage during the afternoon is a bit uncertain/conditional. By late afternoon/evening, a surface front is forecast to progress eastward across the Dakotas and into MN through the nighttime hours. This may provide sufficient forcing for isolated thunderstorm development. Given strong instability and sufficient vertical shear for organized updrafts, large hail (especially with initial cellular development) and damaging gusts will be possible. ...Four Corners into WY and adjacent High Plains... An upper trough will lift northeast across the Great Basin on Sunday. Modestly enhanced southwesterly mid/upper flow will overspread the region between the eastern periphery of the trough and the western periphery of the upper ridge to the east. Boundary-layer moisture will remain modest for most of the region, but steep midlevel lapse rates and strong heating will support 500-1000 J/kg MLCAPE. Sporadic downbursts may produce locally severe gusts with this activity. ...Upper Ohio Valley Vicinity... Modest northwesterly mid/upper flow will overspread the region on Sunday on the western periphery of a Northeast upper trough. Latest forecast guidance shows warming midlevel temps/minor height rises during the day. However, a moist airmass will be in place and weak to moderate destabilization is expected. Convective coverage may be fairly low given latest forecast guidance trends. However, any stronger cells that develop may produce locally strong gusts or small hail given favorable shear and elongated/straight forecast hodographs. ..Leitman.. 08/24/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sat Aug 24 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN DAKOTAS INTO NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe storms may develop across the northern Plains area on Sunday, with more isolated severe potential southwestward into the southern Rockies and adjacent High Plains. A couple of strong/marginally severe storms may also occur across the Lower Great Lakes/Upper Ohio Valley vicinity. ...Northern Plains/Upper Midwest... An upper anticyclone will be centered over KS/OK and the Ozark Plateau, with the upper ridge axis oriented northward over the Upper MS Valley on Sunday. Meanwhile, a shortwave upper trough will migrate east across the Canadian Prairies. This will focus an area of modestly enhanced mid/upper southwesterly flow over the Dakotas into the Upper Midwest. At the surface, south/southeasterly flow will maintain a very moist airmass, with dewpoints in the 70s F expected from the eastern Dakotas into IA/MN and vicinity. A plume of steeper midlevel lapse rates will advect northeast, aiding in strong destabilization. However, warm midlevel temps will likely maintain at least weak MLCIN across the region through the afternoon and into the evening as stronger forcing for ascent largely remains north of the international border. As a result, convective coverage during the afternoon is a bit uncertain/conditional. By late afternoon/evening, a surface front is forecast to progress eastward across the Dakotas and into MN through the nighttime hours. This may provide sufficient forcing for isolated thunderstorm development. Given strong instability and sufficient vertical shear for organized updrafts, large hail (especially with initial cellular development) and damaging gusts will be possible. ...Four Corners into WY and adjacent High Plains... An upper trough will lift northeast across the Great Basin on Sunday. Modestly enhanced southwesterly mid/upper flow will overspread the region between the eastern periphery of the trough and the western periphery of the upper ridge to the east. Boundary-layer moisture will remain modest for most of the region, but steep midlevel lapse rates and strong heating will support 500-1000 J/kg MLCAPE. Sporadic downbursts may produce locally severe gusts with this activity. ...Upper Ohio Valley Vicinity... Modest northwesterly mid/upper flow will overspread the region on Sunday on the western periphery of a Northeast upper trough. Latest forecast guidance shows warming midlevel temps/minor height rises during the day. However, a moist airmass will be in place and weak to moderate destabilization is expected. Convective coverage may be fairly low given latest forecast guidance trends. However, any stronger cells that develop may produce locally strong gusts or small hail given favorable shear and elongated/straight forecast hodographs. ..Leitman.. 08/24/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sat Aug 24 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN DAKOTAS INTO NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe storms may develop across the northern Plains area on Sunday, with more isolated severe potential southwestward into the southern Rockies and adjacent High Plains. A couple of strong/marginally severe storms may also occur across the Lower Great Lakes/Upper Ohio Valley vicinity. ...Northern Plains/Upper Midwest... An upper anticyclone will be centered over KS/OK and the Ozark Plateau, with the upper ridge axis oriented northward over the Upper MS Valley on Sunday. Meanwhile, a shortwave upper trough will migrate east across the Canadian Prairies. This will focus an area of modestly enhanced mid/upper southwesterly flow over the Dakotas into the Upper Midwest. At the surface, south/southeasterly flow will maintain a very moist airmass, with dewpoints in the 70s F expected from the eastern Dakotas into IA/MN and vicinity. A plume of steeper midlevel lapse rates will advect northeast, aiding in strong destabilization. However, warm midlevel temps will likely maintain at least weak MLCIN across the region through the afternoon and into the evening as stronger forcing for ascent largely remains north of the international border. As a result, convective coverage during the afternoon is a bit uncertain/conditional. By late afternoon/evening, a surface front is forecast to progress eastward across the Dakotas and into MN through the nighttime hours. This may provide sufficient forcing for isolated thunderstorm development. Given strong instability and sufficient vertical shear for organized updrafts, large hail (especially with initial cellular development) and damaging gusts will be possible. ...Four Corners into WY and adjacent High Plains... An upper trough will lift northeast across the Great Basin on Sunday. Modestly enhanced southwesterly mid/upper flow will overspread the region between the eastern periphery of the trough and the western periphery of the upper ridge to the east. Boundary-layer moisture will remain modest for most of the region, but steep midlevel lapse rates and strong heating will support 500-1000 J/kg MLCAPE. Sporadic downbursts may produce locally severe gusts with this activity. ...Upper Ohio Valley Vicinity... Modest northwesterly mid/upper flow will overspread the region on Sunday on the western periphery of a Northeast upper trough. Latest forecast guidance shows warming midlevel temps/minor height rises during the day. However, a moist airmass will be in place and weak to moderate destabilization is expected. Convective coverage may be fairly low given latest forecast guidance trends. However, any stronger cells that develop may produce locally strong gusts or small hail given favorable shear and elongated/straight forecast hodographs. ..Leitman.. 08/24/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1214 PM CDT Sat Aug 24 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN DAKOTAS INTO NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe storms may develop across the northern Plains area on Sunday, with more isolated severe potential southwestward into the southern Rockies and adjacent High Plains. A couple of strong/marginally severe storms may also occur across the Lower Great Lakes/Upper Ohio Valley vicinity. ...Northern Plains/Upper Midwest... An upper anticyclone will be centered over KS/OK and the Ozark Plateau, with the upper ridge axis oriented northward over the Upper MS Valley on Sunday. Meanwhile, a shortwave upper trough will migrate east across the Canadian Prairies. This will focus an area of modestly enhanced mid/upper southwesterly flow over the Dakotas into the Upper Midwest. At the surface, south/southeasterly flow will maintain a very moist airmass, with dewpoints in the 70s F expected from the eastern Dakotas into IA/MN and vicinity. A plume of steeper midlevel lapse rates will advect northeast, aiding in strong destabilization. However, warm midlevel temps will likely maintain at least weak MLCIN across the region through the afternoon and into the evening as stronger forcing for ascent largely remains north of the international border. As a result, convective coverage during the afternoon is a bit uncertain/conditional. By late afternoon/evening, a surface front is forecast to progress eastward across the Dakotas and into MN through the nighttime hours. This may provide sufficient forcing for isolated thunderstorm development. Given strong instability and sufficient vertical shear for organized updrafts, large hail (especially with initial cellular development) and damaging gusts will be possible. ...Four Corners into WY and adjacent High Plains... An upper trough will lift northeast across the Great Basin on Sunday. Modestly enhanced southwesterly mid/upper flow will overspread the region between the eastern periphery of the trough and the western periphery of the upper ridge to the east. Boundary-layer moisture will remain modest for most of the region, but steep midlevel lapse rates and strong heating will support 500-1000 J/kg MLCAPE. Sporadic downbursts may produce locally severe gusts with this activity. ...Upper Ohio Valley Vicinity... Modest northwesterly mid/upper flow will overspread the region on Sunday on the western periphery of a Northeast upper trough. Latest forecast guidance shows warming midlevel temps/minor height rises during the day. However, a moist airmass will be in place and weak to moderate destabilization is expected. Convective coverage may be fairly low given latest forecast guidance trends. However, any stronger cells that develop may produce locally strong gusts or small hail given favorable shear and elongated/straight forecast hodographs. ..Leitman.. 08/24/2024 Read more