Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday), though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...SD/MN/IA Vicinity... A broad upper trough will be in place from the Upper Midwest to the Northeast and Mid-Atlantic, resulting in a persistent mid/upper northwest flow regime across the region. Forecast guidance suggests a weak shortwave impulse will move across the eastern Dakotas and MN/IA during the morning/early afternoon. Meanwhile, a weak front will develop southward, extending generally west to east across eastern SD into southern MN by peak heating. Weak southerly low-level flow will promote shallow boundary layer moisture, with surface dewpoints in the upper 50s to low 60s along/ahead of the surface boundary. Midlevel lapse rates are expected to remain modest, but weak instability (around 500-1000 J/kg MLCAPE) is forecast. Some early-day showers and clouds may linger, but isolated thunderstorms will likely develop during mid to late afternoon near the surface boundary from far eastern SD into southern MN. Vertically veering wind profiles, with strengthening northwest flow through the mid/upper levels will support effective shear magnitudes in the 25-35 kt range. Forecast hodographs also appear elongated/straight. While 500 mb temperatures are forecast in the -10 to -12 C range, some warming around 700 mb is apparent in some forecast soundings. While an organized storm or two may become strong within a favorable shear parameter space, it is uncertain if robust updrafts will be maintained given marginal thermodynamics and some contamination to the environment from early-day activity. An isolated strong gust or small hail may be possible with the strongest storms for a couple hours during the late afternoon or early evening, but overall severe potential looks limited at this time. ...Central High Plains... South to southeasterly low-level flow will transport mid 50s to low 60s F dewpoints northwest across the central High Plains beneath modest upper ridging over the western U.S. Daytime heating and a developing lee-trough will provide focus for thunderstorm development by late afternoon along the CO/southeast WY Front Range. Midlevel lapse rates are forecast to remain weak, but sufficient for MLCAPE in the 500-1200 J/kg range. Modestly increasing westerly mid/upper flow will support 20-30 kt effective shear magnitudes and somewhat elongated hodographs. A couple of strong storms capable of sub-severe wind gusts and hail will be possible as convection develops east/southeast into the eastern CO and western KS vicinity through the evening. Overall, severe potential appears limited at this time given the modest thermodynamic and kinematic environment. ..Leitman.. 08/26/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday), though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...SD/MN/IA Vicinity... A broad upper trough will be in place from the Upper Midwest to the Northeast and Mid-Atlantic, resulting in a persistent mid/upper northwest flow regime across the region. Forecast guidance suggests a weak shortwave impulse will move across the eastern Dakotas and MN/IA during the morning/early afternoon. Meanwhile, a weak front will develop southward, extending generally west to east across eastern SD into southern MN by peak heating. Weak southerly low-level flow will promote shallow boundary layer moisture, with surface dewpoints in the upper 50s to low 60s along/ahead of the surface boundary. Midlevel lapse rates are expected to remain modest, but weak instability (around 500-1000 J/kg MLCAPE) is forecast. Some early-day showers and clouds may linger, but isolated thunderstorms will likely develop during mid to late afternoon near the surface boundary from far eastern SD into southern MN. Vertically veering wind profiles, with strengthening northwest flow through the mid/upper levels will support effective shear magnitudes in the 25-35 kt range. Forecast hodographs also appear elongated/straight. While 500 mb temperatures are forecast in the -10 to -12 C range, some warming around 700 mb is apparent in some forecast soundings. While an organized storm or two may become strong within a favorable shear parameter space, it is uncertain if robust updrafts will be maintained given marginal thermodynamics and some contamination to the environment from early-day activity. An isolated strong gust or small hail may be possible with the strongest storms for a couple hours during the late afternoon or early evening, but overall severe potential looks limited at this time. ...Central High Plains... South to southeasterly low-level flow will transport mid 50s to low 60s F dewpoints northwest across the central High Plains beneath modest upper ridging over the western U.S. Daytime heating and a developing lee-trough will provide focus for thunderstorm development by late afternoon along the CO/southeast WY Front Range. Midlevel lapse rates are forecast to remain weak, but sufficient for MLCAPE in the 500-1200 J/kg range. Modestly increasing westerly mid/upper flow will support 20-30 kt effective shear magnitudes and somewhat elongated hodographs. A couple of strong storms capable of sub-severe wind gusts and hail will be possible as convection develops east/southeast into the eastern CO and western KS vicinity through the evening. Overall, severe potential appears limited at this time given the modest thermodynamic and kinematic environment. ..Leitman.. 08/26/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday), though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...SD/MN/IA Vicinity... A broad upper trough will be in place from the Upper Midwest to the Northeast and Mid-Atlantic, resulting in a persistent mid/upper northwest flow regime across the region. Forecast guidance suggests a weak shortwave impulse will move across the eastern Dakotas and MN/IA during the morning/early afternoon. Meanwhile, a weak front will develop southward, extending generally west to east across eastern SD into southern MN by peak heating. Weak southerly low-level flow will promote shallow boundary layer moisture, with surface dewpoints in the upper 50s to low 60s along/ahead of the surface boundary. Midlevel lapse rates are expected to remain modest, but weak instability (around 500-1000 J/kg MLCAPE) is forecast. Some early-day showers and clouds may linger, but isolated thunderstorms will likely develop during mid to late afternoon near the surface boundary from far eastern SD into southern MN. Vertically veering wind profiles, with strengthening northwest flow through the mid/upper levels will support effective shear magnitudes in the 25-35 kt range. Forecast hodographs also appear elongated/straight. While 500 mb temperatures are forecast in the -10 to -12 C range, some warming around 700 mb is apparent in some forecast soundings. While an organized storm or two may become strong within a favorable shear parameter space, it is uncertain if robust updrafts will be maintained given marginal thermodynamics and some contamination to the environment from early-day activity. An isolated strong gust or small hail may be possible with the strongest storms for a couple hours during the late afternoon or early evening, but overall severe potential looks limited at this time. ...Central High Plains... South to southeasterly low-level flow will transport mid 50s to low 60s F dewpoints northwest across the central High Plains beneath modest upper ridging over the western U.S. Daytime heating and a developing lee-trough will provide focus for thunderstorm development by late afternoon along the CO/southeast WY Front Range. Midlevel lapse rates are forecast to remain weak, but sufficient for MLCAPE in the 500-1200 J/kg range. Modestly increasing westerly mid/upper flow will support 20-30 kt effective shear magnitudes and somewhat elongated hodographs. A couple of strong storms capable of sub-severe wind gusts and hail will be possible as convection develops east/southeast into the eastern CO and western KS vicinity through the evening. Overall, severe potential appears limited at this time given the modest thermodynamic and kinematic environment. ..Leitman.. 08/26/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 26 2025 Valid 261700Z - 271200Z Minor modifications were made to the IsoDryT area based on the latest observations and high-resolution forecast guidance. The Oregon Cascades between Eugene and Bend and northward to around Mt. Hood received light rain yesterday over multiple hours, which will make some of the fuels less receptive, and cloud cover is likely to persist over this area today leading to less confidence in that part of the IsoDryT area. High-based showers with isolated thunderstorms producing sporadic lightning are possible over portions of northwest Oregon and western Washington overnight. Please see the previous forecast for more details. ..Nauslar.. 08/26/2025 .PREV DISCUSSION... /ISSUED 0159 AM CDT Tue Aug 26 2025/ ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. ..Gleason/Moore.. 08/26/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Tue Aug 26 2025 Valid 261300Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe storms are not expected across the continental U.S. today. ...Synopsis... An expansive upper-level trough will persist across the eastern CONUS today, where a cool, dry airmass and high pressure will be prevalent and limit thunderstorm potential aside from Florida. Monsoon-related scattered thunderstorms will be common across much of the non-coastal West. ...Southern Arizona/Lower Colorado River Valley... A northward-moving mid-level impulse/MCV will spread from the Lower Colorado River Valley/northern Arizona this morning into Utah, allowing for subsequent clearing/heating across southern Arizona toward the Lower Colorado River Valley. Thunderstorms will again develop and increase this afternoon especially in vicinity of higher terrain. A few instances of strong thunderstorm winds/wet microbursts could occur regionally this afternoon into evening, but the overall potential is expected to remain quite isolated and marginal overall. ..Guyer/Kerr.. 08/26/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Tue Aug 26 2025 Valid 261300Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe storms are not expected across the continental U.S. today. ...Synopsis... An expansive upper-level trough will persist across the eastern CONUS today, where a cool, dry airmass and high pressure will be prevalent and limit thunderstorm potential aside from Florida. Monsoon-related scattered thunderstorms will be common across much of the non-coastal West. ...Southern Arizona/Lower Colorado River Valley... A northward-moving mid-level impulse/MCV will spread from the Lower Colorado River Valley/northern Arizona this morning into Utah, allowing for subsequent clearing/heating across southern Arizona toward the Lower Colorado River Valley. Thunderstorms will again develop and increase this afternoon especially in vicinity of higher terrain. A few instances of strong thunderstorm winds/wet microbursts could occur regionally this afternoon into evening, but the overall potential is expected to remain quite isolated and marginal overall. ..Guyer/Kerr.. 08/26/2025 Read more