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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Sat Sep 21 2024 Valid 212000Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms capable of all hazards are possible this afternoon and evening across portions of the southern High Plains. ...20Z Update... Severe probabilities have been trimmed behind convection in parts of western Pennsylvania as it appears potential for severe storms will be diminished through the remainder of the afternoon. In north-central/northeast Iowa, temperatures have risen into the low 90s ahead of the cold front and near an outflow boundary in the southeast Minnesota/west-central Wisconsin. This area could see a locally higher potential for large hail/damaging winds. Still, linear forcing along the front and very modest mid-level ascent reduces confidence in a discrete storm mode and sufficient storm coverage, precluding any increase in severe probabilities. ..Wendt.. 09/21/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Sep 21 2024/ ...Southern High Plains... A potent upper low and associated 65-75 kt mid-level jet max centered over AZ are expected to quickly move eastward, overspreading the southern Rockies/High Plains this afternoon and evening. At the surface, sustained southerly flow ahead of a deepening surface low and trailing cold front over western NM will support moderate destabilization (MLCAPE 1500-2000 J/kg) with afternoon heating and continued low-level upslope. As the mid-level system approaches, mid-level height falls and flow aloft will intensify, elongating low and mid-level hodographs, allowing for convective development/organization in the form of supercells. One source of continued uncertainty is the ongoing elevated convection and cloud debris centered north of a diffuse surface boundary stretching from central NM to the western TX Panhandle. So far, this boundary has been slowly lifting north with pronounced low-level theta-e advection taking place to the south. As deep-layer ascent intensifies through the late morning, continued convective development to the north may support reinforcement and stalling of the boundary. The northward extent of destabilization remains unclear, though this boundary could serve as a focus for renewed development of more robust convection expected later this afternoon. Most CAM guidance shows scattered thunderstorms initiating off the higher terrain of eastern NM, or ahead of the cold front farther west by early this afternoon. These storms should quickly mature with supportive thermodynamics and kinematics, eventually spreading eastward into the TX Panhandle. The risk for large to very large hail/severe gusts will likely accompany the stronger supercells, and a threat for a couple tornadoes may be realized later this afternoon/early evening from eastern NM into parts of adjacent west TX, especially near the boundary where low-level shear may be locally enhanced. ...Upper Midwest and MO Valley... A second upper low near the international border is forecast to quickly move eastward reaching the western Great Lakes by early this evening. Weak ascent is expected ahead of a surging cold front and diffuse wave cyclone across the northern MO valley and southern MN. Surface moistening with a warm front lifting north near the IA/MN border may act as a focus for more robust convective development along the cold front late this afternoon. Increasingly orthogonal deep-layer flow and steeping low/mid-level lapse rates could support a mix of supercells and multi-cell clusters. A few of the stronger storms may pose some hail/wind threat, which should peak in intensity during the early evening. However, somewhat limited heating and the lack of broader forcing for ascent suggests storm coverage should remain isolated. ...Western PA into the Mid Atlantic... Short-wave troughing across the upper OH Valley within mid-level northwesterly flow is expected to support isolated to widely scattered thunderstorms across western PA/VA later this afternoon. Model forecast soundings with moderate buoyancy and modest deep-layer shear would imply some of the stronger storms being capable of an isolated risk for wind damage (50-60 mph) and perhaps some hail. This activity will likely diminish by early evening coincident with nocturnal cooling. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0222 PM CDT Sat Sep 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO THE OHIO VALLEY AND MID-SOUTH... ...SUMMARY... Isolated strong to severe thunderstorms are possible from the Ozarks to the Ohio Valley and Mid-South region on Monday. ...Synopsis... The mid-level trough over the Southwest on Saturday will start to be absorbed within the more broad westerlies on Monday as it moves into the Missouri region. As this occurs, a belt of mid-level flow will overspread the Ozarks to Ohio Valley region where a moist airmass is in place ahead of a synoptic cold front. This cold front will move slowly east through the period Monday. ...Ozarks to Ohio Valley Region... Extensive cloud-cover from overnight convection will likely limit warm-sector heating from northern Arkansas and southern Missouri to western Kentucky and southern Indiana on Monday. However, at least some breaks in the clouds should result in pockets of greater destabilization, particularly later in the day. Inhibition will be limited across the warm sector, so any areas with greater surface heating will likely convect given the moist airmass and weak height falls during the day. The lack of strong heating or any capping inversion should keep instability somewhat weak through the day and result in a mostly marginal severe threat despite moderate deep-layer shear. A few stronger storms are possible within this zone of weak instability and moderate shear which may pose a threat for large hail or damaging wind gusts. ..Bentley.. 09/21/2024 Read more

MD 2094 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PARTS OF EASTERN NEW MEXICO AND WEST TEXAS
Mesoscale Discussion 2094 NWS Storm Prediction Center Norman OK 0115 PM CDT Sat Sep 21 2024 Areas affected...parts of eastern New Mexico and West Texas Concerning...Severe potential...Watch likely Valid 211815Z - 212015Z Probability of Watch Issuance...80 percent SUMMARY...Persistent upslope flow and daytime heating should allow for continued thunderstorm development early this afternoon over eastern NM. Gradual intensification/organization into supercells is expected. Large to very large hail, damaging gusts, and perhaps a couple of tornadoes are possible. A WW is likely needed. DISCUSSION...As of 1810 UTC, regional WV imagery showed a potent upper low quickly overspreading the southern Rockies and High Plains. Height falls and the approach of a 70 kt speed max will support fairly strong forcing for ascent over the region through the next several hours. Diurnal heating and low-level warm air advection over much of eastern NM and west TX will support moderate destabilization with 1500-2000 J/Kg of MLCAPE expected. In combination with the synoptic scale-forcing and continued upslope of low-60s F surface dewpoints, additional storm development is likely early this afternoon. As convection evolves, the strong mid-level flow aloft will also gradually overspread the area, supporting large effective shear. KFDX VAD data shows veering low and mid-level hodographs have expanded, with 45-50 kt of effective shear present. Storm organization into supercells is expected with time. Fairly steep mid-level lapse rates (~7-8 C/Km) and the semi-discrete mode suggest large to very large hail will be likely with the more robust supercells. Damaging winds and a couple of tornadoes are also possible, owing to the strengthening flow aloft, and enhanced low-level shear near a diffuse surface boundary. Short-term model guidance and observational trends suggest the ongoing convection should steadily increase in intensity/organization through the remainder of the afternoon. Additional storm development/intensification is also likely along the cold front across central NM later this afternoon, though timing remains somewhat uncertain. With the potential for all hazards across much of eastern NM and west TX, a WW appears likely in the next couple of hours. ..Lyons/Guyer.. 09/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LUB...AMA...MAF...ABQ...EPZ... LAT...LON 35490474 36430340 36430178 35850129 35330100 34130133 31620314 31110422 31170503 31580537 32550541 34130526 34720509 35490474 Read more