Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...Synopsis... A large-scale trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the northern/central Rockies and adjacent High Plains. A related lee cyclone will deepen near western SD, promoting a tight pressure gradient and 20-25 mph sustained southerly surface winds (with higher gusts) over portions of western NE during the afternoon. Here, diurnal heating along the western edge of the richer boundary-layer moisture plume should yield 20-30 percent RH. Despite these marginal RH reductions, the strong/gusty winds will still favor a few hours of elevated fire-weather conditions, before a cold front and related precipitation overspread the area during the evening. ..Weinman.. 09/17/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...Synopsis... A large-scale trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the northern/central Rockies and adjacent High Plains. A related lee cyclone will deepen near western SD, promoting a tight pressure gradient and 20-25 mph sustained southerly surface winds (with higher gusts) over portions of western NE during the afternoon. Here, diurnal heating along the western edge of the richer boundary-layer moisture plume should yield 20-30 percent RH. Despite these marginal RH reductions, the strong/gusty winds will still favor a few hours of elevated fire-weather conditions, before a cold front and related precipitation overspread the area during the evening. ..Weinman.. 09/17/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...Synopsis... A large-scale trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the northern/central Rockies and adjacent High Plains. A related lee cyclone will deepen near western SD, promoting a tight pressure gradient and 20-25 mph sustained southerly surface winds (with higher gusts) over portions of western NE during the afternoon. Here, diurnal heating along the western edge of the richer boundary-layer moisture plume should yield 20-30 percent RH. Despite these marginal RH reductions, the strong/gusty winds will still favor a few hours of elevated fire-weather conditions, before a cold front and related precipitation overspread the area during the evening. ..Weinman.. 09/17/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A vertically stacked cyclone over eastern MT at 12Z Wednesday should drift towards the ND/SK/MB border area. A mid-level jetlet of 50-60 kt winds at 500 mb should be confined within the dry slot, near the ND/SD border area on Wednesday afternoon. A dryline should become established from the eastern Dakotas to the southern High Plains. Remnant convective outflows from overnight to decaying morning convection are expected in the confined moist sector ahead of the dryline. The primary cold front attendant to the cyclone should gradually push east in the Dakotas and eventually merge with the retreating dryline early morning Thursday. Large-scale ascent ahead of the dryline appears nebulous for surface-based storms during the afternoon to early evening. Lingering outflows and areas of greater boundary-layer heating should serve to focus isolated thunderstorm development. Guidance varies greatly with placement of convection given the weak forcing for ascent regime. But with a confined plume of moderate MLCAPE from 1500-2000 J/kg and 30-35 kt effective bulk shear, a conditional lower-end supercell environment will exist. Relatively warm mid-level temperatures will contribute to weaker lapse rates south of the Mid-MO Valley, likely being a mitigating factor to more robust updrafts where sustained storms can occur. The bulk of guidance, outside of the 00Z GFS and RRFS, suggest sustained storm development farther north will primarily be a result of low-level warm theta-e advection Wednesday night. As such, severe storm coverage will probably remain rather isolated. ..Grams.. 09/17/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A vertically stacked cyclone over eastern MT at 12Z Wednesday should drift towards the ND/SK/MB border area. A mid-level jetlet of 50-60 kt winds at 500 mb should be confined within the dry slot, near the ND/SD border area on Wednesday afternoon. A dryline should become established from the eastern Dakotas to the southern High Plains. Remnant convective outflows from overnight to decaying morning convection are expected in the confined moist sector ahead of the dryline. The primary cold front attendant to the cyclone should gradually push east in the Dakotas and eventually merge with the retreating dryline early morning Thursday. Large-scale ascent ahead of the dryline appears nebulous for surface-based storms during the afternoon to early evening. Lingering outflows and areas of greater boundary-layer heating should serve to focus isolated thunderstorm development. Guidance varies greatly with placement of convection given the weak forcing for ascent regime. But with a confined plume of moderate MLCAPE from 1500-2000 J/kg and 30-35 kt effective bulk shear, a conditional lower-end supercell environment will exist. Relatively warm mid-level temperatures will contribute to weaker lapse rates south of the Mid-MO Valley, likely being a mitigating factor to more robust updrafts where sustained storms can occur. The bulk of guidance, outside of the 00Z GFS and RRFS, suggest sustained storm development farther north will primarily be a result of low-level warm theta-e advection Wednesday night. As such, severe storm coverage will probably remain rather isolated. ..Grams.. 09/17/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A vertically stacked cyclone over eastern MT at 12Z Wednesday should drift towards the ND/SK/MB border area. A mid-level jetlet of 50-60 kt winds at 500 mb should be confined within the dry slot, near the ND/SD border area on Wednesday afternoon. A dryline should become established from the eastern Dakotas to the southern High Plains. Remnant convective outflows from overnight to decaying morning convection are expected in the confined moist sector ahead of the dryline. The primary cold front attendant to the cyclone should gradually push east in the Dakotas and eventually merge with the retreating dryline early morning Thursday. Large-scale ascent ahead of the dryline appears nebulous for surface-based storms during the afternoon to early evening. Lingering outflows and areas of greater boundary-layer heating should serve to focus isolated thunderstorm development. Guidance varies greatly with placement of convection given the weak forcing for ascent regime. But with a confined plume of moderate MLCAPE from 1500-2000 J/kg and 30-35 kt effective bulk shear, a conditional lower-end supercell environment will exist. Relatively warm mid-level temperatures will contribute to weaker lapse rates south of the Mid-MO Valley, likely being a mitigating factor to more robust updrafts where sustained storms can occur. The bulk of guidance, outside of the 00Z GFS and RRFS, suggest sustained storm development farther north will primarily be a result of low-level warm theta-e advection Wednesday night. As such, severe storm coverage will probably remain rather isolated. ..Grams.. 09/17/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A vertically stacked cyclone over eastern MT at 12Z Wednesday should drift towards the ND/SK/MB border area. A mid-level jetlet of 50-60 kt winds at 500 mb should be confined within the dry slot, near the ND/SD border area on Wednesday afternoon. A dryline should become established from the eastern Dakotas to the southern High Plains. Remnant convective outflows from overnight to decaying morning convection are expected in the confined moist sector ahead of the dryline. The primary cold front attendant to the cyclone should gradually push east in the Dakotas and eventually merge with the retreating dryline early morning Thursday. Large-scale ascent ahead of the dryline appears nebulous for surface-based storms during the afternoon to early evening. Lingering outflows and areas of greater boundary-layer heating should serve to focus isolated thunderstorm development. Guidance varies greatly with placement of convection given the weak forcing for ascent regime. But with a confined plume of moderate MLCAPE from 1500-2000 J/kg and 30-35 kt effective bulk shear, a conditional lower-end supercell environment will exist. Relatively warm mid-level temperatures will contribute to weaker lapse rates south of the Mid-MO Valley, likely being a mitigating factor to more robust updrafts where sustained storms can occur. The bulk of guidance, outside of the 00Z GFS and RRFS, suggest sustained storm development farther north will primarily be a result of low-level warm theta-e advection Wednesday night. As such, severe storm coverage will probably remain rather isolated. ..Grams.. 09/17/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A vertically stacked cyclone over eastern MT at 12Z Wednesday should drift towards the ND/SK/MB border area. A mid-level jetlet of 50-60 kt winds at 500 mb should be confined within the dry slot, near the ND/SD border area on Wednesday afternoon. A dryline should become established from the eastern Dakotas to the southern High Plains. Remnant convective outflows from overnight to decaying morning convection are expected in the confined moist sector ahead of the dryline. The primary cold front attendant to the cyclone should gradually push east in the Dakotas and eventually merge with the retreating dryline early morning Thursday. Large-scale ascent ahead of the dryline appears nebulous for surface-based storms during the afternoon to early evening. Lingering outflows and areas of greater boundary-layer heating should serve to focus isolated thunderstorm development. Guidance varies greatly with placement of convection given the weak forcing for ascent regime. But with a confined plume of moderate MLCAPE from 1500-2000 J/kg and 30-35 kt effective bulk shear, a conditional lower-end supercell environment will exist. Relatively warm mid-level temperatures will contribute to weaker lapse rates south of the Mid-MO Valley, likely being a mitigating factor to more robust updrafts where sustained storms can occur. The bulk of guidance, outside of the 00Z GFS and RRFS, suggest sustained storm development farther north will primarily be a result of low-level warm theta-e advection Wednesday night. As such, severe storm coverage will probably remain rather isolated. ..Grams.. 09/17/2024 Read more

MD 2076 CONCERNING SEVERE THUNDERSTORM WATCH 673... FOR NORTHEAST NORTH DAKOTA/NORTHWEST MINNESOTA
Mesoscale Discussion 2076 NWS Storm Prediction Center Norman OK 1133 PM CDT Mon Sep 16 2024 Areas affected...Northeast North Dakota/Northwest Minnesota Concerning...Severe Thunderstorm Watch 673... Valid 170433Z - 170630Z The severe weather threat for Severe Thunderstorm Watch 673 continues. SUMMARY...Threat for a few strong gusts, and perhaps some marginally severe hail, will spread across northeast North Dakota into northwest Minnesota. DISCUSSION...Long-lived MCV has tracked northeast across ND and is currently located near the international border over northwest Towner County. This feature appears partly responsible for a modest-sized MCS that is progressing across western portions of WW673. Latest surface data suggests the primary front extends from near Grand Forks to south of Harvey, in Wells County. Latest VWP data from MVX exhibits southwesterly LLJ (3km AGL) around 35kt. A well-defined corridor of low-level warm advection should encourage continued eastward propagation of the MCS across northeast ND into northwest MN, perhaps as early as 06z. While a few strong gusts are possible along the leading squall line, only marginally severe hail appears possible along the trailing southwestern flank. New WW is not currently anticipated. ..Darrow.. 09/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF... LAT...LON 49029872 49199674 48549647 48189865 49029872 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of severe wind gusts and isolated large hail will be possible this afternoon and evening across parts of the central and northern High Plains. Wind gusts greater than 70 mph are likely in parts of northeast Colorado, far northwest Kansas and western Nebraska. A marginal potential for severe wind gusts is also expected to develop in parts of the southern and central Rockies, and in parts of eastern Florida. ...High Plains/Central and Southern Rockies... A mid-level low will move across the Intermountain West today, as an associated upper-level trough becomes negatively tilted. A 50 to 65 knot mid-level jet in the base of the trough will move into the central Rockies. Ahead of the system, a lee trough will deepen across the central and northern High Plains. The western edge of a moist airmass will be located just to the east of the surface trough from eastern Colorado into the western Dakotas and eastern Montana. During the day, thunderstorms are expected to develop ahead of the mid-level trough across the central and northern Rockies, with these storms moving east-northeasteastward across the central and northern High Plains during the afternoon and evening. A severe threat will likely accompany many of the stronger storms. Ahead of the approaching trough, partial clearing will result in strong surface heating this afternoon over the central High Plains. MLCAPE is expected to peak near 1500 J/kg from eastern Colorado northward into western Nebraska. A slab of strong large-scale ascent, and an associated mid-level jet will move into the central Plains late this afternoon. This will coincide with strengthening low-level flow and maximized instability, which will make severe storms likely along parts of a convective line moving across the central High Plains. The greatest combination of instability, lift and deep-layer shear is forecast across western Nebraska and northeast Colorado, suggesting an enhanced threat for severe wind gusts. Gusts above 70 mph will be possible ahead of an organized line segment that is expected to move across the central High Plains during the early evening. The potential for severe wind gusts will extend southward and westward into the southern and central Rockies, but the threat will be more isolated in areas where instability remains weak. ...Northern High Plains... A mid-level low will move across the Intermoutain West. Ahead of the low, divergent south to south-southeasterly flow will be in place across the northern Rockies and northern Plains. During the afternoon, thunderstorms will develop in the north-central Rockies and move north to northeastward across the northern High Plains. An axis of moderate instability is forecast by afternoon from the Dakotas northwestward into northeast Montana. As large-scale ascent and moderate deep-layer shear overspread the northern High Plains late this afternoon and evening, organized storms will be possible. Severe wind gusts and isolated large hail will be the primary threats. ...Eastern Florida... A mid-level trough will move across the eastern Gulf of Mexico today, as an associated surface trough moves across the Florida Peninsula. Surface dewpoints in the lower to mid 70s F, along with surface heating will contribute to moderate instability by afternoon. As surface temperatures warm today, scattered thunderstorms are expected to develop along and ahead of the surface trough. RAP forecast soundings at 21Z in eastern Florida have MLCAPE in the 2000 to 3000 J/kg range, with 0-6 km shear around 20 knots. This, combined with steep low-level lapse rates could be enough for a marginal threat for severe wind gusts. ..Broyles/Weinman.. 09/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of severe wind gusts and isolated large hail will be possible this afternoon and evening across parts of the central and northern High Plains. Wind gusts greater than 70 mph are likely in parts of northeast Colorado, far northwest Kansas and western Nebraska. A marginal potential for severe wind gusts is also expected to develop in parts of the southern and central Rockies, and in parts of eastern Florida. ...High Plains/Central and Southern Rockies... A mid-level low will move across the Intermountain West today, as an associated upper-level trough becomes negatively tilted. A 50 to 65 knot mid-level jet in the base of the trough will move into the central Rockies. Ahead of the system, a lee trough will deepen across the central and northern High Plains. The western edge of a moist airmass will be located just to the east of the surface trough from eastern Colorado into the western Dakotas and eastern Montana. During the day, thunderstorms are expected to develop ahead of the mid-level trough across the central and northern Rockies, with these storms moving east-northeasteastward across the central and northern High Plains during the afternoon and evening. A severe threat will likely accompany many of the stronger storms. Ahead of the approaching trough, partial clearing will result in strong surface heating this afternoon over the central High Plains. MLCAPE is expected to peak near 1500 J/kg from eastern Colorado northward into western Nebraska. A slab of strong large-scale ascent, and an associated mid-level jet will move into the central Plains late this afternoon. This will coincide with strengthening low-level flow and maximized instability, which will make severe storms likely along parts of a convective line moving across the central High Plains. The greatest combination of instability, lift and deep-layer shear is forecast across western Nebraska and northeast Colorado, suggesting an enhanced threat for severe wind gusts. Gusts above 70 mph will be possible ahead of an organized line segment that is expected to move across the central High Plains during the early evening. The potential for severe wind gusts will extend southward and westward into the southern and central Rockies, but the threat will be more isolated in areas where instability remains weak. ...Northern High Plains... A mid-level low will move across the Intermoutain West. Ahead of the low, divergent south to south-southeasterly flow will be in place across the northern Rockies and northern Plains. During the afternoon, thunderstorms will develop in the north-central Rockies and move north to northeastward across the northern High Plains. An axis of moderate instability is forecast by afternoon from the Dakotas northwestward into northeast Montana. As large-scale ascent and moderate deep-layer shear overspread the northern High Plains late this afternoon and evening, organized storms will be possible. Severe wind gusts and isolated large hail will be the primary threats. ...Eastern Florida... A mid-level trough will move across the eastern Gulf of Mexico today, as an associated surface trough moves across the Florida Peninsula. Surface dewpoints in the lower to mid 70s F, along with surface heating will contribute to moderate instability by afternoon. As surface temperatures warm today, scattered thunderstorms are expected to develop along and ahead of the surface trough. RAP forecast soundings at 21Z in eastern Florida have MLCAPE in the 2000 to 3000 J/kg range, with 0-6 km shear around 20 knots. This, combined with steep low-level lapse rates could be enough for a marginal threat for severe wind gusts. ..Broyles/Weinman.. 09/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of severe wind gusts and isolated large hail will be possible this afternoon and evening across parts of the central and northern High Plains. Wind gusts greater than 70 mph are likely in parts of northeast Colorado, far northwest Kansas and western Nebraska. A marginal potential for severe wind gusts is also expected to develop in parts of the southern and central Rockies, and in parts of eastern Florida. ...High Plains/Central and Southern Rockies... A mid-level low will move across the Intermountain West today, as an associated upper-level trough becomes negatively tilted. A 50 to 65 knot mid-level jet in the base of the trough will move into the central Rockies. Ahead of the system, a lee trough will deepen across the central and northern High Plains. The western edge of a moist airmass will be located just to the east of the surface trough from eastern Colorado into the western Dakotas and eastern Montana. During the day, thunderstorms are expected to develop ahead of the mid-level trough across the central and northern Rockies, with these storms moving east-northeasteastward across the central and northern High Plains during the afternoon and evening. A severe threat will likely accompany many of the stronger storms. Ahead of the approaching trough, partial clearing will result in strong surface heating this afternoon over the central High Plains. MLCAPE is expected to peak near 1500 J/kg from eastern Colorado northward into western Nebraska. A slab of strong large-scale ascent, and an associated mid-level jet will move into the central Plains late this afternoon. This will coincide with strengthening low-level flow and maximized instability, which will make severe storms likely along parts of a convective line moving across the central High Plains. The greatest combination of instability, lift and deep-layer shear is forecast across western Nebraska and northeast Colorado, suggesting an enhanced threat for severe wind gusts. Gusts above 70 mph will be possible ahead of an organized line segment that is expected to move across the central High Plains during the early evening. The potential for severe wind gusts will extend southward and westward into the southern and central Rockies, but the threat will be more isolated in areas where instability remains weak. ...Northern High Plains... A mid-level low will move across the Intermoutain West. Ahead of the low, divergent south to south-southeasterly flow will be in place across the northern Rockies and northern Plains. During the afternoon, thunderstorms will develop in the north-central Rockies and move north to northeastward across the northern High Plains. An axis of moderate instability is forecast by afternoon from the Dakotas northwestward into northeast Montana. As large-scale ascent and moderate deep-layer shear overspread the northern High Plains late this afternoon and evening, organized storms will be possible. Severe wind gusts and isolated large hail will be the primary threats. ...Eastern Florida... A mid-level trough will move across the eastern Gulf of Mexico today, as an associated surface trough moves across the Florida Peninsula. Surface dewpoints in the lower to mid 70s F, along with surface heating will contribute to moderate instability by afternoon. As surface temperatures warm today, scattered thunderstorms are expected to develop along and ahead of the surface trough. RAP forecast soundings at 21Z in eastern Florida have MLCAPE in the 2000 to 3000 J/kg range, with 0-6 km shear around 20 knots. This, combined with steep low-level lapse rates could be enough for a marginal threat for severe wind gusts. ..Broyles/Weinman.. 09/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of severe wind gusts and isolated large hail will be possible this afternoon and evening across parts of the central and northern High Plains. Wind gusts greater than 70 mph are likely in parts of northeast Colorado, far northwest Kansas and western Nebraska. A marginal potential for severe wind gusts is also expected to develop in parts of the southern and central Rockies, and in parts of eastern Florida. ...High Plains/Central and Southern Rockies... A mid-level low will move across the Intermountain West today, as an associated upper-level trough becomes negatively tilted. A 50 to 65 knot mid-level jet in the base of the trough will move into the central Rockies. Ahead of the system, a lee trough will deepen across the central and northern High Plains. The western edge of a moist airmass will be located just to the east of the surface trough from eastern Colorado into the western Dakotas and eastern Montana. During the day, thunderstorms are expected to develop ahead of the mid-level trough across the central and northern Rockies, with these storms moving east-northeasteastward across the central and northern High Plains during the afternoon and evening. A severe threat will likely accompany many of the stronger storms. Ahead of the approaching trough, partial clearing will result in strong surface heating this afternoon over the central High Plains. MLCAPE is expected to peak near 1500 J/kg from eastern Colorado northward into western Nebraska. A slab of strong large-scale ascent, and an associated mid-level jet will move into the central Plains late this afternoon. This will coincide with strengthening low-level flow and maximized instability, which will make severe storms likely along parts of a convective line moving across the central High Plains. The greatest combination of instability, lift and deep-layer shear is forecast across western Nebraska and northeast Colorado, suggesting an enhanced threat for severe wind gusts. Gusts above 70 mph will be possible ahead of an organized line segment that is expected to move across the central High Plains during the early evening. The potential for severe wind gusts will extend southward and westward into the southern and central Rockies, but the threat will be more isolated in areas where instability remains weak. ...Northern High Plains... A mid-level low will move across the Intermoutain West. Ahead of the low, divergent south to south-southeasterly flow will be in place across the northern Rockies and northern Plains. During the afternoon, thunderstorms will develop in the north-central Rockies and move north to northeastward across the northern High Plains. An axis of moderate instability is forecast by afternoon from the Dakotas northwestward into northeast Montana. As large-scale ascent and moderate deep-layer shear overspread the northern High Plains late this afternoon and evening, organized storms will be possible. Severe wind gusts and isolated large hail will be the primary threats. ...Eastern Florida... A mid-level trough will move across the eastern Gulf of Mexico today, as an associated surface trough moves across the Florida Peninsula. Surface dewpoints in the lower to mid 70s F, along with surface heating will contribute to moderate instability by afternoon. As surface temperatures warm today, scattered thunderstorms are expected to develop along and ahead of the surface trough. RAP forecast soundings at 21Z in eastern Florida have MLCAPE in the 2000 to 3000 J/kg range, with 0-6 km shear around 20 knots. This, combined with steep low-level lapse rates could be enough for a marginal threat for severe wind gusts. ..Broyles/Weinman.. 09/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 17 2024 Valid 171200Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of severe wind gusts and isolated large hail will be possible this afternoon and evening across parts of the central and northern High Plains. Wind gusts greater than 70 mph are likely in parts of northeast Colorado, far northwest Kansas and western Nebraska. A marginal potential for severe wind gusts is also expected to develop in parts of the southern and central Rockies, and in parts of eastern Florida. ...High Plains/Central and Southern Rockies... A mid-level low will move across the Intermountain West today, as an associated upper-level trough becomes negatively tilted. A 50 to 65 knot mid-level jet in the base of the trough will move into the central Rockies. Ahead of the system, a lee trough will deepen across the central and northern High Plains. The western edge of a moist airmass will be located just to the east of the surface trough from eastern Colorado into the western Dakotas and eastern Montana. During the day, thunderstorms are expected to develop ahead of the mid-level trough across the central and northern Rockies, with these storms moving east-northeasteastward across the central and northern High Plains during the afternoon and evening. A severe threat will likely accompany many of the stronger storms. Ahead of the approaching trough, partial clearing will result in strong surface heating this afternoon over the central High Plains. MLCAPE is expected to peak near 1500 J/kg from eastern Colorado northward into western Nebraska. A slab of strong large-scale ascent, and an associated mid-level jet will move into the central Plains late this afternoon. This will coincide with strengthening low-level flow and maximized instability, which will make severe storms likely along parts of a convective line moving across the central High Plains. The greatest combination of instability, lift and deep-layer shear is forecast across western Nebraska and northeast Colorado, suggesting an enhanced threat for severe wind gusts. Gusts above 70 mph will be possible ahead of an organized line segment that is expected to move across the central High Plains during the early evening. The potential for severe wind gusts will extend southward and westward into the southern and central Rockies, but the threat will be more isolated in areas where instability remains weak. ...Northern High Plains... A mid-level low will move across the Intermoutain West. Ahead of the low, divergent south to south-southeasterly flow will be in place across the northern Rockies and northern Plains. During the afternoon, thunderstorms will develop in the north-central Rockies and move north to northeastward across the northern High Plains. An axis of moderate instability is forecast by afternoon from the Dakotas northwestward into northeast Montana. As large-scale ascent and moderate deep-layer shear overspread the northern High Plains late this afternoon and evening, organized storms will be possible. Severe wind gusts and isolated large hail will be the primary threats. ...Eastern Florida... A mid-level trough will move across the eastern Gulf of Mexico today, as an associated surface trough moves across the Florida Peninsula. Surface dewpoints in the lower to mid 70s F, along with surface heating will contribute to moderate instability by afternoon. As surface temperatures warm today, scattered thunderstorms are expected to develop along and ahead of the surface trough. RAP forecast soundings at 21Z in eastern Florida have MLCAPE in the 2000 to 3000 J/kg range, with 0-6 km shear around 20 knots. This, combined with steep low-level lapse rates could be enough for a marginal threat for severe wind gusts. ..Broyles/Weinman.. 09/17/2024 Read more

WW 0673 Status Updates
STATUS REPORT ON WW 673 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 ESE N60 TO 45 WNW DVL TO 55 NNW DVL. ..SPC..09/17/24 ATTN...WFO...FGF...BIS... STATUS REPORT FOR WS 673 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC007-029-069-077-089-113-119-125-135-170540- MN . MINNESOTA COUNTIES INCLUDED ARE BELTRAMI CLEARWATER KITTSON LAKE OF THE WOODS MARSHALL PENNINGTON POLK RED LAKE ROSEAU NDC005-019-027-035-063-067-069-071-095-099-170540- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BENSON CAVALIER EDDY GRAND FORKS NELSON PEMBINA PIERCE RAMSEY TOWNER WALSH THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 673 SEVERE TSTM MN ND 170005Z - 170500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 673 NWS Storm Prediction Center Norman OK 705 PM CDT Mon Sep 16 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwest Minnesota North-central and Northeast North Dakota * Effective this Monday night from 705 PM until Midnight CDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Scattered large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Scattered storms will continue to develop and intensify this evening near and north of a boundary, with at least isolated instances of large hail and damaging winds as the primary hazards. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 105 miles west of Devils Lake ND to 45 miles southeast of Warroad MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 23030. ...Guyer Read more

WW 0673 Status Updates
STATUS REPORT ON WW 673 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 E N60 TO 60 ENE MOT TO 70 NE MOT. ..SPC..09/17/24 ATTN...WFO...FGF...BIS... STATUS REPORT FOR WS 673 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC007-029-069-077-089-113-119-125-135-170440- MN . MINNESOTA COUNTIES INCLUDED ARE BELTRAMI CLEARWATER KITTSON LAKE OF THE WOODS MARSHALL PENNINGTON POLK RED LAKE ROSEAU NDC005-019-027-035-063-067-069-071-079-083-095-099-103-170440- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BENSON CAVALIER EDDY GRAND FORKS NELSON PEMBINA PIERCE RAMSEY ROLETTE SHERIDAN TOWNER WALSH WELLS THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES Read more

MD 2075 CONCERNING SEVERE THUNDERSTORM WATCH 673... FOR PORTIONS OF NORTHERN NORTH DAKOTA
Mesoscale Discussion 2075 NWS Storm Prediction Center Norman OK 0910 PM CDT Mon Sep 16 2024 Areas affected...Portions of northern North Dakota Concerning...Severe Thunderstorm Watch 673... Valid 170210Z - 170345Z The severe weather threat for Severe Thunderstorm Watch 673 continues. SUMMARY...Large hail and severe wind gusts remain possible across portions of northern North Dakota -- within Severe Thunderstorm Watch 673. DISCUSSION...Latest radar data from KMBX indicates a persistent cluster of thunderstorms tracking eastward along an east/west-oriented warm front/stationary boundary draped across northern North Dakota. Along the southern periphery of the cluster, a couple deeper/embedded rotating updrafts are evident, aided by warmer/moister inflow south of the boundary, and favorable/increasing low-level hodograph curvature (sampled by regional VWP data). In the near-term, large hail (generally up to 1.75 inches) and locally severe wind gusts are the primary concerns with these embedded supercell structures. During the next few hours, this cluster of storms should maintain its current intensity and organization as it continues generally eastward along the boundary -- aided by mesoscale forcing associated with an embedded MCV and a plume of low-level warm advection atop the boundary. The primary severe risk may remain focused along the southern periphery of the larger thunderstorm cluster, with less certainty north of the boundary where low-level inhibition is greater. ..Weinman.. 09/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 48040104 48410063 48769990 48899941 48939852 48749794 48249766 47849790 47759825 47600072 47690110 48040104 Read more

WW 0673 Status Updates
STATUS REPORT ON WW 673 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SPC..09/17/24 ATTN...WFO...FGF...BIS... STATUS REPORT FOR WS 673 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC007-029-069-077-089-113-119-125-135-170240- MN . MINNESOTA COUNTIES INCLUDED ARE BELTRAMI CLEARWATER KITTSON LAKE OF THE WOODS MARSHALL PENNINGTON POLK RED LAKE ROSEAU NDC005-009-019-027-035-049-055-063-067-069-071-079-083-095-099- 103-170240- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BENSON BOTTINEAU CAVALIER EDDY GRAND FORKS MCHENRY MCLEAN NELSON PEMBINA PIERCE RAMSEY ROLETTE SHERIDAN TOWNER WALSH WELLS THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL Read more

WW 0673 Status Updates
STATUS REPORT ON WW 673 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SPC..09/17/24 ATTN...WFO...FGF...BIS... STATUS REPORT FOR WS 673 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC007-029-069-077-089-113-119-125-135-170240- MN . MINNESOTA COUNTIES INCLUDED ARE BELTRAMI CLEARWATER KITTSON LAKE OF THE WOODS MARSHALL PENNINGTON POLK RED LAKE ROSEAU NDC005-009-019-027-035-049-055-063-067-069-071-079-083-095-099- 103-170240- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BENSON BOTTINEAU CAVALIER EDDY GRAND FORKS MCHENRY MCLEAN NELSON PEMBINA PIERCE RAMSEY ROLETTE SHERIDAN TOWNER WALSH WELLS THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL Read more