Severe Storms

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

MD 1836 CONCERNING TORNADO WATCH 600... FOR NORTHEASTERN IOWA/SOUTHWESTERN WISCONSIN
Mesoscale Discussion 1836 NWS Storm Prediction Center Norman OK 1125 PM CDT Mon Aug 05 2024 Areas affected...northeastern Iowa/southwestern Wisconsin Concerning...Tornado Watch 600... Valid 060425Z - 060500Z The severe weather threat for Tornado Watch 600 continues. SUMMARY...Tornado risk across the remainder of WW 600 will continue to diminish as storms move eastward/out of the watch. New WW will not be required. DISCUSSION...Latest radar loop shows the strongest storms within the ongoing cluster now moving across southwestern Wisconsin/into WW 601. While a favorable airmass persists near the Mississippi River Valley, storms across northeastern Iowa have remained generally sub-severe, and expect them to largely remain so. As such, it appears reasonable to allow WW 600 to expire as scheduled at 06/05Z. ..Goss.. 08/06/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MKX...DVN...ARX... LAT...LON 42729205 43549060 43479024 42339061 42729205 Read more

MD 1835 CONCERNING TORNADO WATCH 599... FOR COASTAL SOUTHEASTERN SOUTH CAROLINA
Mesoscale Discussion 1835 NWS Storm Prediction Center Norman OK 1035 PM CDT Mon Aug 05 2024 Areas affected...coastal southeastern South Carolina Concerning...Tornado Watch 599... Valid 060335Z - 060500Z The severe weather threat for Tornado Watch 599 continues. SUMMARY...Tornado risk continues in the northeastern quadrant of Debby, as the center of the storm lingers over southeastern Georgia. With Tornado Watch 599 set to expire at 06/05Z, a new WW will likely be required. DISCUSSION...Latest radar loop continues to show cellular convection within a persistent band situated within the northeastern quadrant of Debby's circulation. Stronger offshore cells continue to exhibit compact/occasionally strong circulations, with a couple of tornadoes reported onshore over the past 1 to 2 hours. At this time, it appears that this trend may continue, extending beyond the scheduled expiration of the existing Tornado Watch (599). Given the persistence of a moist/low-CAPE environment combined with very strong low-level shear (weakly veering flow with height, increasing rapidly to 50 kt at around 800m AGL), which should support a continued tornado risk locally, a new watch will likely be required, to cover the ongoing threat. ..Goss.. 08/06/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS... LAT...LON 31418009 31948090 32358128 32688104 32938026 32947941 32207906 31418009 Read more

WW 0602 Status Updates
STATUS FOR WATCH 0602 HAS NOT BEEN ISSUED YET Read more

WW 0601 Status Updates
STATUS REPORT ON WW 601 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE JVL TO 35 WSW RFD TO 25 SE DBQ. ..GOSS..08/06/24 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 601 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-085-177-060540- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL JO DAVIESS STEPHENSON WIC045-049-065-105-060540- WI . WISCONSIN COUNTIES INCLUDED ARE GREEN IOWA LAFAYETTE ROCK 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 0601 Status Updates
STATUS REPORT ON WW 601 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE JVL TO 35 WSW RFD TO 25 SE DBQ. ..GOSS..08/06/24 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 601 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-085-177-060540- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL JO DAVIESS STEPHENSON WIC045-049-065-105-060540- WI . WISCONSIN COUNTIES INCLUDED ARE GREEN IOWA LAFAYETTE ROCK 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 0601 Status Updates
STATUS REPORT ON WW 601 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE JVL TO 35 WSW RFD TO 25 SE DBQ. ..GOSS..08/06/24 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 601 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-085-177-060540- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL JO DAVIESS STEPHENSON WIC045-049-065-105-060540- WI . WISCONSIN COUNTIES INCLUDED ARE GREEN IOWA LAFAYETTE ROCK 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 0601 Status Updates
STATUS REPORT ON WW 601 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE JVL TO 35 WSW RFD TO 25 SE DBQ. ..GOSS..08/06/24 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 601 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-085-177-060540- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL JO DAVIESS STEPHENSON WIC045-049-065-105-060540- WI . WISCONSIN COUNTIES INCLUDED ARE GREEN IOWA LAFAYETTE ROCK 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 0601 Status Updates
STATUS REPORT ON WW 601 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE JVL TO 35 WSW RFD TO 25 SE DBQ. ..GOSS..08/06/24 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 601 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-085-177-060540- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL JO DAVIESS STEPHENSON WIC045-049-065-105-060540- WI . WISCONSIN COUNTIES INCLUDED ARE GREEN IOWA LAFAYETTE ROCK 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 0601 Status Updates
STATUS REPORT ON WW 601 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE JVL TO 35 WSW RFD TO 25 SE DBQ. ..GOSS..08/06/24 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 601 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-085-177-060540- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL JO DAVIESS STEPHENSON WIC045-049-065-105-060540- WI . WISCONSIN COUNTIES INCLUDED ARE GREEN IOWA LAFAYETTE ROCK 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