Severe Storms

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Jul 15 2025 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN PARTS OF NE... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY IN WY... ...SUMMARY... Scattered severe gusts, some significant, and large hail are probable across parts of Nebraska this evening. A mix of scattered damaging winds and severe hail are possible from the Upper Great Lakes into Wyoming this afternoon to mid-evening. ...Synopsis... A positive-tilt shortwave trough over the northern Rockies will pivot eastward into the northern Great Plains by early Wednesday. Low-amplitude shortwave impulses will persist downstream across the southern Canadian Prairies and northern ON. Multiple MCVs will drift east from the central Rockies to Upper Midwest. As surface ridging builds down the High Plains today, a lee cyclone should be centered over the central High Plains this afternoon. The slower-moving portion of the cold front will extend northeast towards Lake Superior. This boundary should become more wavy as extensive convective outflows occur by evening. ...NE/SD... A rather favorable thermodynamic environment will exist ahead of the aforementioned surface low and front by peak heating. Hot and deep-mixed thermodynamic profiles will overlap the western periphery of rich low-level moisture over the eastern plains. Amid very steep mid-level lapse rates, a corridor of large buoyancy with MLCAPE of 2500-3500 J/kg should develop from central NE into southern SD. While mid-level westerlies should be weak, increasing speed shear will exist into the upper levels, fostering large hail growth in initial cells. Scattered thunderstorms are expected along the nose of the low-level thermal ridge as a minor mid-level impulse near the MT/WY border shifts east into central SD during the late afternoon to early evening. Progressively higher-based storms should flank to the southwest towards the lee cyclone. Pronounced low-level convergence along the front is expected through the evening. This setup should favor the large hail threat transitioning to upscale growth and a potential severe MCS. ARW-NSSL forecast soundings indicate potential for a 75-kt rear-inflow jet, which would be conducive to significant severe surface gusts. The most likely corridor for these to occur is centered on the central NE vicinity. This MCS may persist overnight but should wane owing to lessening instability/increasing MLCIN. ...Upper Great Lakes/Midwest... Remnants of ongoing convection are expected to be ongoing at 12Z across the northeast MN/far northwest WI/western Lake Superior vicinity. This activity may persist into late morning but should diminish/shift east of the international border. The trailing outflow-reinforced front will be the focus for renewed storm development during the afternoon. The most likely corridor is from central MN into western Upper MI, as an MCV approaches from central SD. Guidance varies on the degree of timing, but early afternoon initiation appears plausible. In west-central MN to eastern SD, guidance has more spread in the degree of convective coverage along this portion of the front, likely related to MCV timing. Ample buoyancy south of the boundary in MN to northwest WI will foster potential for an initial hail threat before multicell clusters yield sporadic damaging winds. ...WY to eastern Great Basin... Mid-level height falls attendant to the aforementioned northern Rockies shortwave trough will favor scattered to widespread thunderstorms, peaking in the late afternoon to early evening. The highest probability of organized storms will be across WY, as a compact 40-50 kt jetlet becomes centered near the Yellowstone vicinity. Downstream surface ridging will modulate the northeast extent of severe potential. But a confined corridor centered along the surface front should be favored for an organized cluster. With inverted-v thermodynamic profiles south of the front, a swath of severe gusts and isolated severe hail are possible from 22-03Z. Very deeply mixed thermodynamic profiles will be prevalent into parts of UT to northeast NV. Weak deep-layer shear will yield disorganized cells, but any of this activity will be capable of erratic severe gusts. ...Southeast AZ... Weak mid-level east-northeasterlies and a hot boundary layer could support localized severe gusts from late afternoon through dusk. ..Grams/Thornton.. 07/15/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Jul 15 2025 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN PARTS OF NE... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY IN WY... ...SUMMARY... Scattered severe gusts, some significant, and large hail are probable across parts of Nebraska this evening. A mix of scattered damaging winds and severe hail are possible from the Upper Great Lakes into Wyoming this afternoon to mid-evening. ...Synopsis... A positive-tilt shortwave trough over the northern Rockies will pivot eastward into the northern Great Plains by early Wednesday. Low-amplitude shortwave impulses will persist downstream across the southern Canadian Prairies and northern ON. Multiple MCVs will drift east from the central Rockies to Upper Midwest. As surface ridging builds down the High Plains today, a lee cyclone should be centered over the central High Plains this afternoon. The slower-moving portion of the cold front will extend northeast towards Lake Superior. This boundary should become more wavy as extensive convective outflows occur by evening. ...NE/SD... A rather favorable thermodynamic environment will exist ahead of the aforementioned surface low and front by peak heating. Hot and deep-mixed thermodynamic profiles will overlap the western periphery of rich low-level moisture over the eastern plains. Amid very steep mid-level lapse rates, a corridor of large buoyancy with MLCAPE of 2500-3500 J/kg should develop from central NE into southern SD. While mid-level westerlies should be weak, increasing speed shear will exist into the upper levels, fostering large hail growth in initial cells. Scattered thunderstorms are expected along the nose of the low-level thermal ridge as a minor mid-level impulse near the MT/WY border shifts east into central SD during the late afternoon to early evening. Progressively higher-based storms should flank to the southwest towards the lee cyclone. Pronounced low-level convergence along the front is expected through the evening. This setup should favor the large hail threat transitioning to upscale growth and a potential severe MCS. ARW-NSSL forecast soundings indicate potential for a 75-kt rear-inflow jet, which would be conducive to significant severe surface gusts. The most likely corridor for these to occur is centered on the central NE vicinity. This MCS may persist overnight but should wane owing to lessening instability/increasing MLCIN. ...Upper Great Lakes/Midwest... Remnants of ongoing convection are expected to be ongoing at 12Z across the northeast MN/far northwest WI/western Lake Superior vicinity. This activity may persist into late morning but should diminish/shift east of the international border. The trailing outflow-reinforced front will be the focus for renewed storm development during the afternoon. The most likely corridor is from central MN into western Upper MI, as an MCV approaches from central SD. Guidance varies on the degree of timing, but early afternoon initiation appears plausible. In west-central MN to eastern SD, guidance has more spread in the degree of convective coverage along this portion of the front, likely related to MCV timing. Ample buoyancy south of the boundary in MN to northwest WI will foster potential for an initial hail threat before multicell clusters yield sporadic damaging winds. ...WY to eastern Great Basin... Mid-level height falls attendant to the aforementioned northern Rockies shortwave trough will favor scattered to widespread thunderstorms, peaking in the late afternoon to early evening. The highest probability of organized storms will be across WY, as a compact 40-50 kt jetlet becomes centered near the Yellowstone vicinity. Downstream surface ridging will modulate the northeast extent of severe potential. But a confined corridor centered along the surface front should be favored for an organized cluster. With inverted-v thermodynamic profiles south of the front, a swath of severe gusts and isolated severe hail are possible from 22-03Z. Very deeply mixed thermodynamic profiles will be prevalent into parts of UT to northeast NV. Weak deep-layer shear will yield disorganized cells, but any of this activity will be capable of erratic severe gusts. ...Southeast AZ... Weak mid-level east-northeasterlies and a hot boundary layer could support localized severe gusts from late afternoon through dusk. ..Grams/Thornton.. 07/15/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Jul 15 2025 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN PARTS OF NE... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY IN WY... ...SUMMARY... Scattered severe gusts, some significant, and large hail are probable across parts of Nebraska this evening. A mix of scattered damaging winds and severe hail are possible from the Upper Great Lakes into Wyoming this afternoon to mid-evening. ...Synopsis... A positive-tilt shortwave trough over the northern Rockies will pivot eastward into the northern Great Plains by early Wednesday. Low-amplitude shortwave impulses will persist downstream across the southern Canadian Prairies and northern ON. Multiple MCVs will drift east from the central Rockies to Upper Midwest. As surface ridging builds down the High Plains today, a lee cyclone should be centered over the central High Plains this afternoon. The slower-moving portion of the cold front will extend northeast towards Lake Superior. This boundary should become more wavy as extensive convective outflows occur by evening. ...NE/SD... A rather favorable thermodynamic environment will exist ahead of the aforementioned surface low and front by peak heating. Hot and deep-mixed thermodynamic profiles will overlap the western periphery of rich low-level moisture over the eastern plains. Amid very steep mid-level lapse rates, a corridor of large buoyancy with MLCAPE of 2500-3500 J/kg should develop from central NE into southern SD. While mid-level westerlies should be weak, increasing speed shear will exist into the upper levels, fostering large hail growth in initial cells. Scattered thunderstorms are expected along the nose of the low-level thermal ridge as a minor mid-level impulse near the MT/WY border shifts east into central SD during the late afternoon to early evening. Progressively higher-based storms should flank to the southwest towards the lee cyclone. Pronounced low-level convergence along the front is expected through the evening. This setup should favor the large hail threat transitioning to upscale growth and a potential severe MCS. ARW-NSSL forecast soundings indicate potential for a 75-kt rear-inflow jet, which would be conducive to significant severe surface gusts. The most likely corridor for these to occur is centered on the central NE vicinity. This MCS may persist overnight but should wane owing to lessening instability/increasing MLCIN. ...Upper Great Lakes/Midwest... Remnants of ongoing convection are expected to be ongoing at 12Z across the northeast MN/far northwest WI/western Lake Superior vicinity. This activity may persist into late morning but should diminish/shift east of the international border. The trailing outflow-reinforced front will be the focus for renewed storm development during the afternoon. The most likely corridor is from central MN into western Upper MI, as an MCV approaches from central SD. Guidance varies on the degree of timing, but early afternoon initiation appears plausible. In west-central MN to eastern SD, guidance has more spread in the degree of convective coverage along this portion of the front, likely related to MCV timing. Ample buoyancy south of the boundary in MN to northwest WI will foster potential for an initial hail threat before multicell clusters yield sporadic damaging winds. ...WY to eastern Great Basin... Mid-level height falls attendant to the aforementioned northern Rockies shortwave trough will favor scattered to widespread thunderstorms, peaking in the late afternoon to early evening. The highest probability of organized storms will be across WY, as a compact 40-50 kt jetlet becomes centered near the Yellowstone vicinity. Downstream surface ridging will modulate the northeast extent of severe potential. But a confined corridor centered along the surface front should be favored for an organized cluster. With inverted-v thermodynamic profiles south of the front, a swath of severe gusts and isolated severe hail are possible from 22-03Z. Very deeply mixed thermodynamic profiles will be prevalent into parts of UT to northeast NV. Weak deep-layer shear will yield disorganized cells, but any of this activity will be capable of erratic severe gusts. ...Southeast AZ... Weak mid-level east-northeasterlies and a hot boundary layer could support localized severe gusts from late afternoon through dusk. ..Grams/Thornton.. 07/15/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Jul 15 2025 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN PARTS OF NE... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY IN WY... ...SUMMARY... Scattered severe gusts, some significant, and large hail are probable across parts of Nebraska this evening. A mix of scattered damaging winds and severe hail are possible from the Upper Great Lakes into Wyoming this afternoon to mid-evening. ...Synopsis... A positive-tilt shortwave trough over the northern Rockies will pivot eastward into the northern Great Plains by early Wednesday. Low-amplitude shortwave impulses will persist downstream across the southern Canadian Prairies and northern ON. Multiple MCVs will drift east from the central Rockies to Upper Midwest. As surface ridging builds down the High Plains today, a lee cyclone should be centered over the central High Plains this afternoon. The slower-moving portion of the cold front will extend northeast towards Lake Superior. This boundary should become more wavy as extensive convective outflows occur by evening. ...NE/SD... A rather favorable thermodynamic environment will exist ahead of the aforementioned surface low and front by peak heating. Hot and deep-mixed thermodynamic profiles will overlap the western periphery of rich low-level moisture over the eastern plains. Amid very steep mid-level lapse rates, a corridor of large buoyancy with MLCAPE of 2500-3500 J/kg should develop from central NE into southern SD. While mid-level westerlies should be weak, increasing speed shear will exist into the upper levels, fostering large hail growth in initial cells. Scattered thunderstorms are expected along the nose of the low-level thermal ridge as a minor mid-level impulse near the MT/WY border shifts east into central SD during the late afternoon to early evening. Progressively higher-based storms should flank to the southwest towards the lee cyclone. Pronounced low-level convergence along the front is expected through the evening. This setup should favor the large hail threat transitioning to upscale growth and a potential severe MCS. ARW-NSSL forecast soundings indicate potential for a 75-kt rear-inflow jet, which would be conducive to significant severe surface gusts. The most likely corridor for these to occur is centered on the central NE vicinity. This MCS may persist overnight but should wane owing to lessening instability/increasing MLCIN. ...Upper Great Lakes/Midwest... Remnants of ongoing convection are expected to be ongoing at 12Z across the northeast MN/far northwest WI/western Lake Superior vicinity. This activity may persist into late morning but should diminish/shift east of the international border. The trailing outflow-reinforced front will be the focus for renewed storm development during the afternoon. The most likely corridor is from central MN into western Upper MI, as an MCV approaches from central SD. Guidance varies on the degree of timing, but early afternoon initiation appears plausible. In west-central MN to eastern SD, guidance has more spread in the degree of convective coverage along this portion of the front, likely related to MCV timing. Ample buoyancy south of the boundary in MN to northwest WI will foster potential for an initial hail threat before multicell clusters yield sporadic damaging winds. ...WY to eastern Great Basin... Mid-level height falls attendant to the aforementioned northern Rockies shortwave trough will favor scattered to widespread thunderstorms, peaking in the late afternoon to early evening. The highest probability of organized storms will be across WY, as a compact 40-50 kt jetlet becomes centered near the Yellowstone vicinity. Downstream surface ridging will modulate the northeast extent of severe potential. But a confined corridor centered along the surface front should be favored for an organized cluster. With inverted-v thermodynamic profiles south of the front, a swath of severe gusts and isolated severe hail are possible from 22-03Z. Very deeply mixed thermodynamic profiles will be prevalent into parts of UT to northeast NV. Weak deep-layer shear will yield disorganized cells, but any of this activity will be capable of erratic severe gusts. ...Southeast AZ... Weak mid-level east-northeasterlies and a hot boundary layer could support localized severe gusts from late afternoon through dusk. ..Grams/Thornton.. 07/15/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Jul 15 2025 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN PARTS OF NE... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY IN WY... ...SUMMARY... Scattered severe gusts, some significant, and large hail are probable across parts of Nebraska this evening. A mix of scattered damaging winds and severe hail are possible from the Upper Great Lakes into Wyoming this afternoon to mid-evening. ...Synopsis... A positive-tilt shortwave trough over the northern Rockies will pivot eastward into the northern Great Plains by early Wednesday. Low-amplitude shortwave impulses will persist downstream across the southern Canadian Prairies and northern ON. Multiple MCVs will drift east from the central Rockies to Upper Midwest. As surface ridging builds down the High Plains today, a lee cyclone should be centered over the central High Plains this afternoon. The slower-moving portion of the cold front will extend northeast towards Lake Superior. This boundary should become more wavy as extensive convective outflows occur by evening. ...NE/SD... A rather favorable thermodynamic environment will exist ahead of the aforementioned surface low and front by peak heating. Hot and deep-mixed thermodynamic profiles will overlap the western periphery of rich low-level moisture over the eastern plains. Amid very steep mid-level lapse rates, a corridor of large buoyancy with MLCAPE of 2500-3500 J/kg should develop from central NE into southern SD. While mid-level westerlies should be weak, increasing speed shear will exist into the upper levels, fostering large hail growth in initial cells. Scattered thunderstorms are expected along the nose of the low-level thermal ridge as a minor mid-level impulse near the MT/WY border shifts east into central SD during the late afternoon to early evening. Progressively higher-based storms should flank to the southwest towards the lee cyclone. Pronounced low-level convergence along the front is expected through the evening. This setup should favor the large hail threat transitioning to upscale growth and a potential severe MCS. ARW-NSSL forecast soundings indicate potential for a 75-kt rear-inflow jet, which would be conducive to significant severe surface gusts. The most likely corridor for these to occur is centered on the central NE vicinity. This MCS may persist overnight but should wane owing to lessening instability/increasing MLCIN. ...Upper Great Lakes/Midwest... Remnants of ongoing convection are expected to be ongoing at 12Z across the northeast MN/far northwest WI/western Lake Superior vicinity. This activity may persist into late morning but should diminish/shift east of the international border. The trailing outflow-reinforced front will be the focus for renewed storm development during the afternoon. The most likely corridor is from central MN into western Upper MI, as an MCV approaches from central SD. Guidance varies on the degree of timing, but early afternoon initiation appears plausible. In west-central MN to eastern SD, guidance has more spread in the degree of convective coverage along this portion of the front, likely related to MCV timing. Ample buoyancy south of the boundary in MN to northwest WI will foster potential for an initial hail threat before multicell clusters yield sporadic damaging winds. ...WY to eastern Great Basin... Mid-level height falls attendant to the aforementioned northern Rockies shortwave trough will favor scattered to widespread thunderstorms, peaking in the late afternoon to early evening. The highest probability of organized storms will be across WY, as a compact 40-50 kt jetlet becomes centered near the Yellowstone vicinity. Downstream surface ridging will modulate the northeast extent of severe potential. But a confined corridor centered along the surface front should be favored for an organized cluster. With inverted-v thermodynamic profiles south of the front, a swath of severe gusts and isolated severe hail are possible from 22-03Z. Very deeply mixed thermodynamic profiles will be prevalent into parts of UT to northeast NV. Weak deep-layer shear will yield disorganized cells, but any of this activity will be capable of erratic severe gusts. ...Southeast AZ... Weak mid-level east-northeasterlies and a hot boundary layer could support localized severe gusts from late afternoon through dusk. ..Grams/Thornton.. 07/15/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Tue Jul 15 2025 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN PARTS OF NE... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY IN WY... ...SUMMARY... Scattered severe gusts, some significant, and large hail are probable across parts of Nebraska this evening. A mix of scattered damaging winds and severe hail are possible from the Upper Great Lakes into Wyoming this afternoon to mid-evening. ...Synopsis... A positive-tilt shortwave trough over the northern Rockies will pivot eastward into the northern Great Plains by early Wednesday. Low-amplitude shortwave impulses will persist downstream across the southern Canadian Prairies and northern ON. Multiple MCVs will drift east from the central Rockies to Upper Midwest. As surface ridging builds down the High Plains today, a lee cyclone should be centered over the central High Plains this afternoon. The slower-moving portion of the cold front will extend northeast towards Lake Superior. This boundary should become more wavy as extensive convective outflows occur by evening. ...NE/SD... A rather favorable thermodynamic environment will exist ahead of the aforementioned surface low and front by peak heating. Hot and deep-mixed thermodynamic profiles will overlap the western periphery of rich low-level moisture over the eastern plains. Amid very steep mid-level lapse rates, a corridor of large buoyancy with MLCAPE of 2500-3500 J/kg should develop from central NE into southern SD. While mid-level westerlies should be weak, increasing speed shear will exist into the upper levels, fostering large hail growth in initial cells. Scattered thunderstorms are expected along the nose of the low-level thermal ridge as a minor mid-level impulse near the MT/WY border shifts east into central SD during the late afternoon to early evening. Progressively higher-based storms should flank to the southwest towards the lee cyclone. Pronounced low-level convergence along the front is expected through the evening. This setup should favor the large hail threat transitioning to upscale growth and a potential severe MCS. ARW-NSSL forecast soundings indicate potential for a 75-kt rear-inflow jet, which would be conducive to significant severe surface gusts. The most likely corridor for these to occur is centered on the central NE vicinity. This MCS may persist overnight but should wane owing to lessening instability/increasing MLCIN. ...Upper Great Lakes/Midwest... Remnants of ongoing convection are expected to be ongoing at 12Z across the northeast MN/far northwest WI/western Lake Superior vicinity. This activity may persist into late morning but should diminish/shift east of the international border. The trailing outflow-reinforced front will be the focus for renewed storm development during the afternoon. The most likely corridor is from central MN into western Upper MI, as an MCV approaches from central SD. Guidance varies on the degree of timing, but early afternoon initiation appears plausible. In west-central MN to eastern SD, guidance has more spread in the degree of convective coverage along this portion of the front, likely related to MCV timing. Ample buoyancy south of the boundary in MN to northwest WI will foster potential for an initial hail threat before multicell clusters yield sporadic damaging winds. ...WY to eastern Great Basin... Mid-level height falls attendant to the aforementioned northern Rockies shortwave trough will favor scattered to widespread thunderstorms, peaking in the late afternoon to early evening. The highest probability of organized storms will be across WY, as a compact 40-50 kt jetlet becomes centered near the Yellowstone vicinity. Downstream surface ridging will modulate the northeast extent of severe potential. But a confined corridor centered along the surface front should be favored for an organized cluster. With inverted-v thermodynamic profiles south of the front, a swath of severe gusts and isolated severe hail are possible from 22-03Z. Very deeply mixed thermodynamic profiles will be prevalent into parts of UT to northeast NV. Weak deep-layer shear will yield disorganized cells, but any of this activity will be capable of erratic severe gusts. ...Southeast AZ... Weak mid-level east-northeasterlies and a hot boundary layer could support localized severe gusts from late afternoon through dusk. ..Grams/Thornton.. 07/15/2025 Read more

MD 1672 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF CENTRAL/NORTHEASTERN NORTH DAKOTA THROUGH NORTH CENTRAL MINNESOTA
Mesoscale Discussion 1672 NWS Storm Prediction Center Norman OK 1051 PM CDT Mon Jul 14 2025 Areas affected...parts of central/northeastern North Dakota through north central Minnesota Concerning...Severe potential...Watch possible Valid 150351Z - 150545Z Probability of Watch Issuance...40 percent SUMMARY...Intensifying thunderstorm development could support increasing potential for severe hail during the next few hours, with some possibility for storms to organize and perhaps become accompanied by strong to locally severe gusts overnight. It is still not clear that a severe weather watch will be needed, but trends are being monitored for this possibility. DISCUSSION...Thunderstorm development, rooted within forcing for ascent associated with low-level warm advection, is underway southwest of Devils Lake, near the Carrington vicinity of central North Dakota. This is based above a relatively cool, stable boundary layer, to the north of a developing warm frontal zone arcing across east central North Dakota into north central Minnesota. Into the 06-07Z time frame, the strengthening Minnesota segment of the frontal zone is forecast to shift northward, roughly from the Brainerd through Bemidji vicinity. This is also focused along the northern periphery of a plume of warmer and more strongly capping elevated mixed-layer air. Although south to southwesterly low-level flow remains weak beneath modest westerly mid-level flow on the southern fringe of the westerlies, a strengthening low-level jet (in excess of 30 kt around 850 mb) across South Dakota is forecast to nose northeastward toward the Jamestown through Grand Forks vicinity of North Dakota within the next couple of hours. As this occurs, strengthening forcing for ascent will probably become supportive of increasingly thunderstorm development, which may gradually organize in the presence of strengthening shear. Forecast soundings indicate at least a narrow corridor of sizable CAPE for elevated moist parcels along the frontal zone, providing support for the potential evolution of a few supercell structures. This probably will be accompanied by a risk for large hail. Given the elevated nature of the convection, and the presence of a stable near surface layer, the risk for strong to severe surface gusts appears low, at least initially. However, it might not be out of the question that gravity waves generated by intensifying convection could contribute to surface pressure perturbations supportive of strong surface gusts, as convection develops eastward along the frontal zone into north central Minnesota overnight. ..Kerr/Thompson.. 07/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH...FGF...BIS... LAT...LON 47889956 48499704 48189362 47369365 47279653 47179951 47889956 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more

WW 0512 Status Updates
STATUS FOR WATCH 0512 HAS NOT BEEN ISSUED YET Read more

WW 0512 Status Updates
STATUS FOR WATCH 0512 HAS NOT BEEN ISSUED YET Read more

WW 0511 Status Updates
STATUS REPORT ON WW 511 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 ENE CDR TO 20 S PIR TO 40 NNE PIR AND 45 ENE CDR TO 20 S PIR TO 35 NNW PIR. REMAINING VALID PORTION OF WW 511 MAY BE ALLOWED TO EXPIRE AT 15/03Z. ..KERR..07/15/25 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 511 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-041-065-075-085-095-107-121-123-150300- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT DEWEY HUGHES JONES LYMAN MELLETTE POTTER TODD TRIPP 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 0511 Status Updates
STATUS REPORT ON WW 511 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 ENE CDR TO 20 S PIR TO 40 NNE PIR AND 45 ENE CDR TO 20 S PIR TO 35 NNW PIR. REMAINING VALID PORTION OF WW 511 MAY BE ALLOWED TO EXPIRE AT 15/03Z. ..KERR..07/15/25 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 511 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-041-065-075-085-095-107-121-123-150300- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT DEWEY HUGHES JONES LYMAN MELLETTE POTTER TODD TRIPP 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 0511 Status Updates
STATUS REPORT ON WW 511 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 ENE CDR TO 20 S PIR TO 40 NNE PIR AND 45 ENE CDR TO 20 S PIR TO 35 NNW PIR. REMAINING VALID PORTION OF WW 511 MAY BE ALLOWED TO EXPIRE AT 15/03Z. ..KERR..07/15/25 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 511 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-041-065-075-085-095-107-121-123-150300- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT DEWEY HUGHES JONES LYMAN MELLETTE POTTER TODD TRIPP 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 0511 Status Updates
STATUS REPORT ON WW 511 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 ENE CDR TO 20 S PIR TO 40 NNE PIR AND 45 ENE CDR TO 20 S PIR TO 35 NNW PIR. REMAINING VALID PORTION OF WW 511 MAY BE ALLOWED TO EXPIRE AT 15/03Z. ..KERR..07/15/25 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 511 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-041-065-075-085-095-107-121-123-150300- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT DEWEY HUGHES JONES LYMAN MELLETTE POTTER TODD TRIPP 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 0511 Status Updates
STATUS REPORT ON WW 511 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 ENE CDR TO 20 S PIR TO 40 NNE PIR AND 45 ENE CDR TO 20 S PIR TO 35 NNW PIR. REMAINING VALID PORTION OF WW 511 MAY BE ALLOWED TO EXPIRE AT 15/03Z. ..KERR..07/15/25 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 511 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-041-065-075-085-095-107-121-123-150300- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT DEWEY HUGHES JONES LYMAN MELLETTE POTTER TODD TRIPP 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

MD 1671 CONCERNING SEVERE THUNDERSTORM WATCH 511... FOR PARTS OF SOUTH CENTRAL SOUTH DAKOTA AND ADJACENT NORTHERN NEBRASKA
Mesoscale Discussion 1671 NWS Storm Prediction Center Norman OK 0750 PM CDT Mon Jul 14 2025 Areas affected...parts of south central South Dakota and adjacent northern Nebraska Concerning...Severe Thunderstorm Watch 511... Valid 150050Z - 150245Z The severe weather threat for Severe Thunderstorm Watch 511 continues. SUMMARY...As storms spread into south central South Dakota during the next couple of hours, intensities may begin to wane, but an additional strong downburst or two remains possible. DISCUSSION...A linear band of stronger thunderstorm development persists north through northeast of the Pine Ridge Reservation, along the leading edge of a conglomerate surface cold pool. This is advancing eastward into a lingering strongly heated and deeply mixed boundary-layer west of Winner northward into the Pierre vicinity. Although it is not clear that this air mass is characterized by sufficient instability to maintain vigorous thunderstorm development, it still appears conducive to an additional strong downburst or two, before convection weakens. The strong to severe gust potential could be aided by the downward transfer of momentum associated with nocturnal low-level jet strengthening as the boundary-layer begins to decouple. ..Kerr.. 07/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...UNR... LAT...LON 43410128 43890067 44310007 43149963 43080175 43410128 Read more