Severe Storms

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Mon Aug 05 2024 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT ACROSS PARTS OF COASTAL NORTH AND SOUTH CAROLINA...AND PARTS OF NORTHEASTERN COLORADO AND SOUTHEASTERN WYOMING INTO WESTERN NEBRASKA AND NORTHWESTERN KANSAS... ...SUMMARY... A few strong thunderstorms may impact parts of the coastal Carolinas, and parts of the Front Range into adjacent Great Plains, Wednesday afternoon into Wednesday night, accompanied by at least some risk for severe weather. ...Synopsis... Mid-level troughing across the Canadian Prairies through adjacent international border area may make some progress into the northern U.S. Great Plains during this period, while also elongating westward across British Columbia, between one prominent ridge centered across the Canadian Northwest Territories and another across the southern U.S. Great Basin into the southern Great Plains. Downstream, mid-level heights are generally forecast to rise across much of Quebec, the Canadian Maritimes and northern New England, as significant troughing finally begins to shift east of the region. However, one more significant impulse is forecast to dig south-southwestward across southern Hudson Bay by late Wednesday night. Across the Southeast and southern mid- to subtropical Atlantic, developments remain a bit more unclear. Considerable spread remains evident concerning west-northwestward development of the western Atlantic ridge, and its potential influence on what is currently still forecast to be a tropical storm offshore of the South Carolina coast at 12Z Wednesday. ...Carolinas/Southeastern Georgia... Due to the slow moving nature of the remnant tropical cyclone and the uncertainty concerning its track, tornado potential for Wednesday through Wednesday night remains unclear. However, based on the current official forecast intensity and track of Debby, low tornado probabilities may mostly focus near and perhaps just inland of southern North Carolina coastal areas, as the low-level circulation center begins to slowly accelerate northeastward and northward late Wednesday through Wednesday night. ...Front Range into adjacent Great Plains... It now appears that stronger boundary-layer destabilization (including CAPE on the order of 1500-2000 J/kg by late afternoon) will mostly focus within lee surface troughing across parts of northwestern Kansas and western Nebraska into the Cheyenne Ridge vicinity. And models seem increasingly suggestive that large-scale forcing for ascent may support the initiation of storms off the higher terrain to the west and southwest, into an initially more strongly heated and deeply mixed boundary layer. Aided by strong shear associated with strengthening westerly mid/upper flow (including 35 to 40+ kt around 500 mb), convection may tend to grow upscale and organize as surface cold pools strengthen and consolidate, with potential for further intensification into Wednesday evening as it progress into the better instability. Damaging winds and large hail may accompany this convection, and it is possible that severe probabilities could be increased in later outlooks for this period. ..Kerr.. 08/06/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Mon Aug 05 2024 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT ACROSS PARTS OF COASTAL NORTH AND SOUTH CAROLINA...AND PARTS OF NORTHEASTERN COLORADO AND SOUTHEASTERN WYOMING INTO WESTERN NEBRASKA AND NORTHWESTERN KANSAS... ...SUMMARY... A few strong thunderstorms may impact parts of the coastal Carolinas, and parts of the Front Range into adjacent Great Plains, Wednesday afternoon into Wednesday night, accompanied by at least some risk for severe weather. ...Synopsis... Mid-level troughing across the Canadian Prairies through adjacent international border area may make some progress into the northern U.S. Great Plains during this period, while also elongating westward across British Columbia, between one prominent ridge centered across the Canadian Northwest Territories and another across the southern U.S. Great Basin into the southern Great Plains. Downstream, mid-level heights are generally forecast to rise across much of Quebec, the Canadian Maritimes and northern New England, as significant troughing finally begins to shift east of the region. However, one more significant impulse is forecast to dig south-southwestward across southern Hudson Bay by late Wednesday night. Across the Southeast and southern mid- to subtropical Atlantic, developments remain a bit more unclear. Considerable spread remains evident concerning west-northwestward development of the western Atlantic ridge, and its potential influence on what is currently still forecast to be a tropical storm offshore of the South Carolina coast at 12Z Wednesday. ...Carolinas/Southeastern Georgia... Due to the slow moving nature of the remnant tropical cyclone and the uncertainty concerning its track, tornado potential for Wednesday through Wednesday night remains unclear. However, based on the current official forecast intensity and track of Debby, low tornado probabilities may mostly focus near and perhaps just inland of southern North Carolina coastal areas, as the low-level circulation center begins to slowly accelerate northeastward and northward late Wednesday through Wednesday night. ...Front Range into adjacent Great Plains... It now appears that stronger boundary-layer destabilization (including CAPE on the order of 1500-2000 J/kg by late afternoon) will mostly focus within lee surface troughing across parts of northwestern Kansas and western Nebraska into the Cheyenne Ridge vicinity. And models seem increasingly suggestive that large-scale forcing for ascent may support the initiation of storms off the higher terrain to the west and southwest, into an initially more strongly heated and deeply mixed boundary layer. Aided by strong shear associated with strengthening westerly mid/upper flow (including 35 to 40+ kt around 500 mb), convection may tend to grow upscale and organize as surface cold pools strengthen and consolidate, with potential for further intensification into Wednesday evening as it progress into the better instability. Damaging winds and large hail may accompany this convection, and it is possible that severe probabilities could be increased in later outlooks for this period. ..Kerr.. 08/06/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Mon Aug 05 2024 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT ACROSS PARTS OF COASTAL NORTH AND SOUTH CAROLINA...AND PARTS OF NORTHEASTERN COLORADO AND SOUTHEASTERN WYOMING INTO WESTERN NEBRASKA AND NORTHWESTERN KANSAS... ...SUMMARY... A few strong thunderstorms may impact parts of the coastal Carolinas, and parts of the Front Range into adjacent Great Plains, Wednesday afternoon into Wednesday night, accompanied by at least some risk for severe weather. ...Synopsis... Mid-level troughing across the Canadian Prairies through adjacent international border area may make some progress into the northern U.S. Great Plains during this period, while also elongating westward across British Columbia, between one prominent ridge centered across the Canadian Northwest Territories and another across the southern U.S. Great Basin into the southern Great Plains. Downstream, mid-level heights are generally forecast to rise across much of Quebec, the Canadian Maritimes and northern New England, as significant troughing finally begins to shift east of the region. However, one more significant impulse is forecast to dig south-southwestward across southern Hudson Bay by late Wednesday night. Across the Southeast and southern mid- to subtropical Atlantic, developments remain a bit more unclear. Considerable spread remains evident concerning west-northwestward development of the western Atlantic ridge, and its potential influence on what is currently still forecast to be a tropical storm offshore of the South Carolina coast at 12Z Wednesday. ...Carolinas/Southeastern Georgia... Due to the slow moving nature of the remnant tropical cyclone and the uncertainty concerning its track, tornado potential for Wednesday through Wednesday night remains unclear. However, based on the current official forecast intensity and track of Debby, low tornado probabilities may mostly focus near and perhaps just inland of southern North Carolina coastal areas, as the low-level circulation center begins to slowly accelerate northeastward and northward late Wednesday through Wednesday night. ...Front Range into adjacent Great Plains... It now appears that stronger boundary-layer destabilization (including CAPE on the order of 1500-2000 J/kg by late afternoon) will mostly focus within lee surface troughing across parts of northwestern Kansas and western Nebraska into the Cheyenne Ridge vicinity. And models seem increasingly suggestive that large-scale forcing for ascent may support the initiation of storms off the higher terrain to the west and southwest, into an initially more strongly heated and deeply mixed boundary layer. Aided by strong shear associated with strengthening westerly mid/upper flow (including 35 to 40+ kt around 500 mb), convection may tend to grow upscale and organize as surface cold pools strengthen and consolidate, with potential for further intensification into Wednesday evening as it progress into the better instability. Damaging winds and large hail may accompany this convection, and it is possible that severe probabilities could be increased in later outlooks for this period. ..Kerr.. 08/06/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Mon Aug 05 2024 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT ACROSS PARTS OF COASTAL NORTH AND SOUTH CAROLINA...AND PARTS OF NORTHEASTERN COLORADO AND SOUTHEASTERN WYOMING INTO WESTERN NEBRASKA AND NORTHWESTERN KANSAS... ...SUMMARY... A few strong thunderstorms may impact parts of the coastal Carolinas, and parts of the Front Range into adjacent Great Plains, Wednesday afternoon into Wednesday night, accompanied by at least some risk for severe weather. ...Synopsis... Mid-level troughing across the Canadian Prairies through adjacent international border area may make some progress into the northern U.S. Great Plains during this period, while also elongating westward across British Columbia, between one prominent ridge centered across the Canadian Northwest Territories and another across the southern U.S. Great Basin into the southern Great Plains. Downstream, mid-level heights are generally forecast to rise across much of Quebec, the Canadian Maritimes and northern New England, as significant troughing finally begins to shift east of the region. However, one more significant impulse is forecast to dig south-southwestward across southern Hudson Bay by late Wednesday night. Across the Southeast and southern mid- to subtropical Atlantic, developments remain a bit more unclear. Considerable spread remains evident concerning west-northwestward development of the western Atlantic ridge, and its potential influence on what is currently still forecast to be a tropical storm offshore of the South Carolina coast at 12Z Wednesday. ...Carolinas/Southeastern Georgia... Due to the slow moving nature of the remnant tropical cyclone and the uncertainty concerning its track, tornado potential for Wednesday through Wednesday night remains unclear. However, based on the current official forecast intensity and track of Debby, low tornado probabilities may mostly focus near and perhaps just inland of southern North Carolina coastal areas, as the low-level circulation center begins to slowly accelerate northeastward and northward late Wednesday through Wednesday night. ...Front Range into adjacent Great Plains... It now appears that stronger boundary-layer destabilization (including CAPE on the order of 1500-2000 J/kg by late afternoon) will mostly focus within lee surface troughing across parts of northwestern Kansas and western Nebraska into the Cheyenne Ridge vicinity. And models seem increasingly suggestive that large-scale forcing for ascent may support the initiation of storms off the higher terrain to the west and southwest, into an initially more strongly heated and deeply mixed boundary layer. Aided by strong shear associated with strengthening westerly mid/upper flow (including 35 to 40+ kt around 500 mb), convection may tend to grow upscale and organize as surface cold pools strengthen and consolidate, with potential for further intensification into Wednesday evening as it progress into the better instability. Damaging winds and large hail may accompany this convection, and it is possible that severe probabilities could be increased in later outlooks for this period. ..Kerr.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Tue Aug 06 2024 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDWEST TO THE MID-ATLANTIC...OVER MONTANA INTO WESTERN SOUTH DAKOTA...AND PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Scattered strong storms are likely over much of Montana into western South Dakota, as well as from parts of Ohio into New Jersey, and across parts of Arizona. ...MI/IN/OH into the Northern Mid-Atlantic Vicinity... A convectively enhanced shortwave impulse will track east from southern Lake Michigan to southern New England today into this evening. Enhanced midlevel flow associated with this feature will overspread the region. At the surface, a stalled boundary will extend west to east from northern IN/OH into central PA and eventually offshore in the vicinity of Long Island. An MCV is forecast to shift east along this boundary today into this evening. A very moist airmass is in place, and surface dewpoints in the low to possibly mid-70s F are expected to contribute to moderate to strong instability. Forecast soundings depict steepening low-level lapse rates and PW values near 2 inches. Furthermore, supercell wind profiles are evident. Low-level hodographs will be somewhat enlarged and favorably curved in the vicinity of the surface boundary and near the eastward-developing MCV. This will support a risk for a few tornadoes from northern OH into western PA. Otherwise, cells/clusters will pose a risk for damaging gusts and marginal hail across a broader area within the theta-e gradient/surface boundary from IN to the northern Mid-Atlantic coast. With time, and aided enhanced ascent from the MCV, one or more bowing segments may develop. If this occurs, damaging-wind potential could increase across portions of the area. ...Northern Rockies to the Northern High Plains... An upper shortwave trough will develop south over western Canada and the northern Rockies. This will flatten the upper ridge oriented over the MT and the Dakotas and result in increasing mid/upper westerly flow across the region. Cooling aloft will foster steep midlevel lapse rates, while increasing midlevel moisture further aids in weak to moderate destabilization over the region (MLCAPE 500-1500 J/kg). Initial convection is forecast to develop over the higher terrain of western MT by early/mid afternoon. Around 25-35 kt effective shear magnitudes will support organized cells. Meanwhile, cooling midlevel temperatures and elongated/straight hodographs should support isolated large hail with initial discrete storms. With time, clustering and outflow consolidation is expected as convection shifts east into central/eastern MT and eventually the western Dakotas during the evening. Steep low-level lapse rates and deeply mixed boundary layer will support strong to severe outflow gusts with this activity. ...Central/Southern AZ... Midlevel easterly flow will increase to around 20-25 kt as a weak impulse migrates westward near the AZ/Mexican border. Steep low to midlevel lapse rates and nearly 1.5 inch PW values will support MLCAPE around 1500-2000 J/kg amid 30 kt effective shear magnitudes. Initial thunderstorm development is expected over higher terrain by early to mid-afternoon. With time, clustering and outflow consolidation should result in westward propagating convection posing a risk for severe gusts into the evening. ...Coastal Carolinas... Tropical Storm Debby will not move much today, remaining near coastal SC. Overall tornado potential appears somewhat less compared to the previous couple of days, as widespread heavy rain will limit low-level destabilization. However, enhanced low-level shear within the eastern semicircle may support a low risk for a tornado or two across portions of coastal SC and southeast NC. ...Central High Plains... A post-frontal upslope flow regime will maintain modest boundary-layer moisture across the central High Plains vicinity. Strong heating and steep midlevel lapse rates will support MLCAPE to around 1500 J/kg. While deep-layer flow will remain modest, vertically veering wind profiles will provide sufficient shear for semi-organized cells. Convection will develop near higher terrain by 18-20z and spread east into the adjacent plains through the evening. This activity will pose a risk for marginal wind/hail before weakening after sunset. ..Leitman/Thornton.. 08/06/2024 Read more

WW 0602 Status Updates
STATUS REPORT ON WW 602 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION ..DEAN..08/06/24 ATTN...WFO...CHS...ILM... STATUS REPORT FOR WT 602 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SCC013-015-019-029-035-043-053-060640- SC . SOUTH CAROLINA COUNTIES INCLUDED ARE BEAUFORT BERKELEY CHARLESTON COLLETON DORCHESTER GEORGETOWN JASPER AMZ256-276-330-350-352-370-372-060640- CW . ADJACENT COASTAL WATERS INCLUDED ARE COASTAL WATERS FROM MURRELLS INLET TO SOUTH SANTEE RIVER SC OUT 20 NM WATERS FROM MURRELLS INLET NC TO SOUTH SANTEE RIVER SC FROM 20 TO 40 NM CHARLESTON HARBOR Read more

MD 1837 CONCERNING SEVERE THUNDERSTORM WATCH 601... FOR PARTS OF SOUTHERN WISCONSIN AND NORTHWESTERN ILLINOIS
Mesoscale Discussion 1837 NWS Storm Prediction Center Norman OK 1138 PM CDT Mon Aug 05 2024 Areas affected...parts of southern Wisconsin and northwestern Illinois Concerning...Severe Thunderstorm Watch 601... Valid 060438Z - 060515Z The severe weather threat for Severe Thunderstorm Watch 601 continues. SUMMARY...Local severe risk may continue for another 1 to 2 hours across southwestern Wisconsin and far northwestern Illinois. WW 601 will likely be extended in time, beyond its scheduled 06/05Z expiration, to cover this ongoing threat. DISCUSSION...Latest radar loop shows a cluster of strong/severe storms moving east-southeastward out across southwestern Wisconsin, out of WW 600 and into WW 601. Low-level moisture/instability diminishes with eastward extent across southern Wisconsin, where an easterly low-level lake fetch is indicated. However, ample instability -- particularly across Grant and Iowa Counties in Wisconsin and areas directly south in northwestern Illinois -- remains, which should allow this cluster of storms to persist awhile longer. With some accompanying severe risk -- mainly in the form of damaging wind -- to affect these counties, WW 601 will likely be extended in time to cover this potential. ..Goss.. 08/06/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX... LAT...LON 43199040 42858889 42048962 41979019 42489043 43199040 Read more