SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Jul 15, 2025 1730 UTC Day 2 Convective Outlook

Severe Storms
1 week ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND THE WESTERN GREAT LAKES REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Front Range and High Plains... A shortwave trough over the northern Rockies will intensify as it moves eastward across the central US Wednesday. A cold front across the Front Range and High Plains will continue to sag slowly southward as surface moisture deepens behind it. Within the broad up slope flow regime, scattered storm development is expected across the higher terrain of the central Rockies and High Plains by early afternoon Wednesday. Enhanced mid-level flow will support initial supercells capable of hail and isolated damaging gusts. Local terrain effects and enhanced low-level shear near the front may also allow for a tornado or two. Scattered severe storms expand in coverage across the I-25 corridor through the afternoon before moving eastward into the plains through the evening. How far east the severe threat will extend remains uncertain as cooler temperatures and lingering inhibition are likely to be in place behind the front. Should sufficient upscale growth take place, an MCS may develop and merge with additional convection farther east before continuing south/southeastward across the central Plains overnight. This would support a continued risk for at least isolated damaging gusts. ...Central Plains... As the cold front continues to move southward across the central Plains, lingering inhibition and forcing for ascent displaced to the north should limit convective development along the front through much of the day However, warm surface temperatures and 60s-70s F surface dewpoints will support large buoyancy along the front. As a 30-40 kt low-level jet increases into the evening, storm development is expected with increasing low-level warm air advection. Isolated damaging gust are possible. ...Great Lakes... A convectively augmented shortwave trough over the central Plains will quickly move eastward along the sagging cold front. Ascent from this feature will aid in developing a wave cyclone along the front, enhancing the low-level flow field across parts of WI and northern IL. An ongoing arc of storms near the surface low should gradually re-intensify through the morning and into the early afternoon. Moderate MLCAPE and strengthening flow aloft will support a mix of cells and clusters. The primary risk is expected to be damaging gusts, though enlarged low-level hodographs and 100-200 J/kg of MLCAPE below 3km AGL may support some tornado risk with the more cellular elements. With time gradual upscale growth into a more linear structure is expected near the western shores of Lake Michigan with a continued risk for damaging gusts. To the east, strong heating of a very humid air mass is expected across Lower Michigan through the afternoon. Scattered to widespread storms are likely along the typical lake breeze fronts. Vertical shear will be weaker through the afternoon, though at least some enhancement of the flow field could support isolated damaging gusts with scattered to numerous storms expected. There is some potential for a more organized line/cluster of storms on the western side of the lake to move eastward across Lake Michigan late in the evening and through the overnight hours. Stronger flow aloft near the shortwave trough could support damaging gust and brief tornado potential across parts of northern Lower Michigan overnight. Higher severe probabilities could be needed if confidence in this convective scenario increases in future outlooks. ...Upper OH valley... Widespread thunderstorms are expected across the region in response to a shortwave impulse. Modest instability is forecast amid a very moist airmass. While vertical shear will remain fairly limited, some slight enhancement near the upper trough could support a few longer-lived storm clusters. Isolated strong gusts/wet microbursts could occur, with the more intense storms. ...Northern Gulf Coast... Scattered to numerous thunderstorms associated with Invest 93L will occasionally move onshore across the northern/central Gulf Coast Wednesday and Wednesday night. Enhancement of low and mid-level easterly shear north of the weak surface circulation may support a few longer-lived cells near the coast. Sporadic damaging gusts and perhaps a brief tornado are possible, though confidence in this convective scenario is very low. ..Lyons.. 07/15/2025 Read more

SPC Day 1 Fire Weather Outlook

Severe Storms
1 week ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Tue Jul 15 2025 Valid 151700Z - 161200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEASTERN NEVADA...NORTHWESTERN UTAH AND SOUTH CENTRAL IDAHO... ...CRITICAL FIRE WEATHER AREA FOR EASTERN NEVADA INTO WESTERN UTAH AND NORTHERN ARIZONA... ...Dry Thunderstorms... A mid-level trough and attendant increased mid-level flow will provide support for more sustained convection across portions northeastern NV, far northwestern UT and south-central ID this afternoon. High-based thunderstorm motions of 25-30 mph will limit rainfall to less than 0.10 inch while also bringing potential new ignitions over a very dry fuelscape in addition to gusty and erratic outflow winds from downbursts. Less concentrated but still impactful elevated thunderstorms will bring new ignition potential to portions of the Four Corners area, much of UT, northeastern NV, southeastern ID and western WY. Otherwise, dry and breezy conditions across the Snake River Plain and the Great Basin will bring elevated fire weather conditions to the region today. A critical fire weather threat remains for portions of southeast NV, southwestern UT and the Arizona Strip. ..Williams.. 07/15/2025 .PREV DISCUSSION... /ISSUED 0154 AM CDT Tue Jul 15 2025/ ...Synopsis... An active day for fire weather is expected across the Southwest and Great Basin today. A deepening mid-level wave will bring an increase in winds and potential for dry thunderstorms across the Great Basin today. Elevated to Critical conditions can be expected in portions of eastern Nevada, western Utah, northern Arizona and southern Idaho. ...Eastern Nevada, western Utah, northern Arizona... West to southwesterly flow around 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent across portions of eastern NV, western UT, and northern AZ. Fuels in these regions are critically dry, with notable increase in fire activity over the last couple of weeks. In addition to background surface winds, nearby thunderstorm activity may further produce gusty and erratic outflow winds. ...Dry Thunderstorms... A broad area of dry thunderstorms will be possible across portions of northern Arizona into western Colorado, Utah, far southern Idaho, western Wyoming, and Nevada. Moisture varies across these regions with potential for a mix of wet/dry storms in a few locations. Moisture remains mostly mid-level and with increased storm motions expected with the passage of the mid-level trough, it is likely that rainfall will be limited and local with new lightning ignitions possible. Fuels are critically dry with an uptick in fire activity over last several weeks. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1630 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Tue Jul 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK INTO THE UPPER MIDWEST...FOR NORTHERN AND EASTERN WYOMING...AND NORTHERN UTAH AND SURROUNDING VICINITY... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. Scattered severe gusts are also possible from the Upper Midwest to Utah and Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Midwest... Primary focus for thunderstorms will be a slowly sagging, southward-moving cold front across the Upper Midwest and a couple mid-level perturbations moving east across the north-central states. Radar imagery shows a convectively augment disturbance moving east across northern SD and water-vapor imagery shows shortwave trough moving east across southeast WY. Both mid-level features will likely prove instrumental in storm coverage and the risk for severe activity later today. Despite stronger mid-level westerly flow relegated north of the 48th parallel, strong heating of a moist airmass will result in a very unstable boundary layer by mid afternoon from the Upper Midwest southwestward into the NE Sandhills. Storms will probably develop from eastern SD and into MN this afternoon near the front and ahead of the SD mid-level feature. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely be present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The only change for this portion of the region is to increase severe-wind probabilities across northern UT and surrounding states. The southern fringe of stronger mid-level westerlies was sampled by the 12 UTC Salt Lake City raob. With the approach of the upstream northern Rockies disturbance glancing the region later today, short-term model guidance (e.g., HREF members, time-lagged HRRR) is consistent in showing small clusters of storms moving east from northeast NV/northwest UT eastward into northern UT/southeast ID/far southwest WY. Inverted-V profiles will strongly favor evaporative cooling with the more rain-laden cores. Scattered severe gusts are possible with the more intense downbursts through early evening. Farther east, the closer proximity to the upper trough digging southeastward over the northern Rockies will promote scattered storms across northern into eastern WY this afternoon and evening. An organized cluster may evolve given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Smith/Jirak.. 07/15/2025 Read more

SPC Jul 15, 2025 1300 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0734 AM CDT Tue Jul 15 2025 Valid 151300Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WYOMING... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. A mix of scattered severe/damaging winds and large hail should also occur from the Upper Great Lakes to Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Great Lakes... A belt of stronger mid-level westerly flow will remain confined generally along/north of the international border today. Even so, multiple weak mid-level perturbations, some of which are related to prior/ongoing convection, will aid in additional thunderstorm development later this afternoon and evening across portions of the northern/central Plains to upper Great Lakes. This convection will also be aided by a slowly southward sagging cold front across SD into NE, as a weak low develops northeastward across the Upper Midwest into Canada along this boundary. As diurnal heating occurs today, a moist and moderately to strongly unstable airmass will exist by this afternoon along/south of the front from NE into parts of SD, MN, and the U.P. of MI. While stronger flow aloft will tend to remain to the north of the front, there should still be sufficient deep-layer shear across the warm sector for some updraft organization. Current expectations are for robust thunderstorms to develop along the front in MN by early afternoon, and quickly spread eastward across northern WI, the U.P. of MI, and Lake Superior through the rest of the afternoon into the evening. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates and ample instability. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The upper trough digging southeastward over the northern Rockies today will influence convective development this afternoon across parts of the northern Great Basin and WY vicinity. High-based convection that occurs across parts of eastern NV into UT will occur in a relatively dry profile, with limited total precipitable water. Still, a deeply mixed boundary layer coupled with weak instability should support some risk for severe gusts with this activity as it moves generally east-northeastward this afternoon/evening across the northern Great Basin vicinity. Greater low-level moisture, with surface dewpoints generally in the low to mid 50s, is already present this morning over parts northern WY. Convection that initially develops near Yellowstone in northwest WY may grow upscale fairly quickly into an organized cluster given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. The Slight Risk across WY has been expanded northward/eastward some based on latest guidance trends. This cluster should eventually weaken late this evening/tonight as it approaches the WY/NE/SD border vicinity. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Gleason/Bentley.. 07/15/2025 Read more

SPC Jul 15, 2025 1300 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0734 AM CDT Tue Jul 15 2025 Valid 151300Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WYOMING... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. A mix of scattered severe/damaging winds and large hail should also occur from the Upper Great Lakes to Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Great Lakes... A belt of stronger mid-level westerly flow will remain confined generally along/north of the international border today. Even so, multiple weak mid-level perturbations, some of which are related to prior/ongoing convection, will aid in additional thunderstorm development later this afternoon and evening across portions of the northern/central Plains to upper Great Lakes. This convection will also be aided by a slowly southward sagging cold front across SD into NE, as a weak low develops northeastward across the Upper Midwest into Canada along this boundary. As diurnal heating occurs today, a moist and moderately to strongly unstable airmass will exist by this afternoon along/south of the front from NE into parts of SD, MN, and the U.P. of MI. While stronger flow aloft will tend to remain to the north of the front, there should still be sufficient deep-layer shear across the warm sector for some updraft organization. Current expectations are for robust thunderstorms to develop along the front in MN by early afternoon, and quickly spread eastward across northern WI, the U.P. of MI, and Lake Superior through the rest of the afternoon into the evening. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates and ample instability. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The upper trough digging southeastward over the northern Rockies today will influence convective development this afternoon across parts of the northern Great Basin and WY vicinity. High-based convection that occurs across parts of eastern NV into UT will occur in a relatively dry profile, with limited total precipitable water. Still, a deeply mixed boundary layer coupled with weak instability should support some risk for severe gusts with this activity as it moves generally east-northeastward this afternoon/evening across the northern Great Basin vicinity. Greater low-level moisture, with surface dewpoints generally in the low to mid 50s, is already present this morning over parts northern WY. Convection that initially develops near Yellowstone in northwest WY may grow upscale fairly quickly into an organized cluster given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. The Slight Risk across WY has been expanded northward/eastward some based on latest guidance trends. This cluster should eventually weaken late this evening/tonight as it approaches the WY/NE/SD border vicinity. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Gleason/Bentley.. 07/15/2025 Read more

SPC Jul 15, 2025 1300 UTC Day 1 Convective Outlook

Severe Storms
1 week ago
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0734 AM CDT Tue Jul 15 2025 Valid 151300Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEBRASKA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WYOMING... ...SUMMARY... Scattered severe gusts (some 75+ mph) and large hail are probable across parts of Nebraska late this afternoon and evening. A mix of scattered severe/damaging winds and large hail should also occur from the Upper Great Lakes to Wyoming this afternoon to mid-evening. ...Northern/Central Plains to the Upper Great Lakes... A belt of stronger mid-level westerly flow will remain confined generally along/north of the international border today. Even so, multiple weak mid-level perturbations, some of which are related to prior/ongoing convection, will aid in additional thunderstorm development later this afternoon and evening across portions of the northern/central Plains to upper Great Lakes. This convection will also be aided by a slowly southward sagging cold front across SD into NE, as a weak low develops northeastward across the Upper Midwest into Canada along this boundary. As diurnal heating occurs today, a moist and moderately to strongly unstable airmass will exist by this afternoon along/south of the front from NE into parts of SD, MN, and the U.P. of MI. While stronger flow aloft will tend to remain to the north of the front, there should still be sufficient deep-layer shear across the warm sector for some updraft organization. Current expectations are for robust thunderstorms to develop along the front in MN by early afternoon, and quickly spread eastward across northern WI, the U.P. of MI, and Lake Superior through the rest of the afternoon into the evening. Sufficient instability and effective bulk shear should be present along/ahead of the front to support organized convection, including some supercells. Large hail will be possible with the initially semi-discrete thunderstorms, before a rapid transition to a cluster/linear mode increases the threat for severe/damaging winds. This activity should quickly weaken by late evening as it encounters a less unstable airmass with eastward extent across the upper Great Lakes. A somewhat separate area of thunderstorms should initiate along/south of the front across parts of southern SD into NE by late afternoon/early evening. Greater instability will likely present across this region compared to locations farther north, but deep-layer shear should be more modest (around 25-30 kt). Still, some large hail may occur initially given the presence of steep mid-level lapse rates and ample instability. The threat for scattered to numerous severe/damaging winds is expected to increase through the evening across central NE as an intense bowing cluster develops and spreads southeastward. Isolated significant gusts of 75+ mph appear possible given the rather favorable thermodynamic environment. ...Great Basin into Wyoming... The upper trough digging southeastward over the northern Rockies today will influence convective development this afternoon across parts of the northern Great Basin and WY vicinity. High-based convection that occurs across parts of eastern NV into UT will occur in a relatively dry profile, with limited total precipitable water. Still, a deeply mixed boundary layer coupled with weak instability should support some risk for severe gusts with this activity as it moves generally east-northeastward this afternoon/evening across the northern Great Basin vicinity. Greater low-level moisture, with surface dewpoints generally in the low to mid 50s, is already present this morning over parts northern WY. Convection that initially develops near Yellowstone in northwest WY may grow upscale fairly quickly into an organized cluster given 25-35 kt of deep-layer shear, while posing a threat for mainly severe/damaging winds given the presence of steepened low/mid-level lapse rates. Isolated large hail may also occur. The Slight Risk across WY has been expanded northward/eastward some based on latest guidance trends. This cluster should eventually weaken late this evening/tonight as it approaches the WY/NE/SD border vicinity. ...Arizona... Modest mid-level east-northeasterlies will be present today across parts of AZ on the southern periphery of a mid-level anticyclone over the Southwest. Scattered thunderstorms should once again develop this afternoon over the higher terrain of southeast AZ and southwest NM. With very steep low/mid-level lapse rates expected with ample daytime heating, this activity may pose an isolated threat for severe winds as it spreads into the lower elevations of southern AZ through the evening. ..Gleason/Bentley.. 07/15/2025 Read more
Checked
5 years 9 months ago
Severe Storms
Storm Prediction Center
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https://www.spc.noaa.gov/
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