Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...Synopsis... The upper-level trough in the Northwest will become more diffuse on Tuesday. Mid-level winds will slacken across the Great Basin. A weak surface trough/boundary will remain in northern Nevada. ...Southern/central Nevada... While surface winds will generally be weaker than previous days, the surface pressure gradient near the boundary will support 15-20 mph in portions of southern/central Nevada. RH of 15-20% appears possible during the afternoon. Area fuels remain dry enough to support elevated fire weather conditions. ..Wendt.. 07/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...Synopsis... The upper-level trough in the Northwest will become more diffuse on Tuesday. Mid-level winds will slacken across the Great Basin. A weak surface trough/boundary will remain in northern Nevada. ...Southern/central Nevada... While surface winds will generally be weaker than previous days, the surface pressure gradient near the boundary will support 15-20 mph in portions of southern/central Nevada. RH of 15-20% appears possible during the afternoon. Area fuels remain dry enough to support elevated fire weather conditions. ..Wendt.. 07/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0201 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...Synopsis... The upper-level trough in the Northwest will become more diffuse on Tuesday. Mid-level winds will slacken across the Great Basin. A weak surface trough/boundary will remain in northern Nevada. ...Southern/central Nevada... While surface winds will generally be weaker than previous days, the surface pressure gradient near the boundary will support 15-20 mph in portions of southern/central Nevada. RH of 15-20% appears possible during the afternoon. Area fuels remain dry enough to support elevated fire weather conditions. ..Wendt.. 07/21/2025 ...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 0200 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN AND NORTH-CENTRAL NEVADA... ...Synopsis... With the base of the upper-level trough pivoting into the northern Great Basin today, a belt of stronger mid-level flow will stretch from northern California into northern Nevada and the northern Rockies. At the surface, a low in northeast Nevada/northern Utah will modestly deepen. ...Western/central Great Basin into western Wyoming... A relatively broad area of elevated fire weather is expected across much of the western/northern Great Basin into western Wyoming. RH will fall to 10-20% in Nevada while 15-20% will be more common farther north and east. Surface winds of 15-20 mph will develop by the afternoon. Critical fire weather is expected to occur in northwest and north-central Nevada. Here, the marginally stronger pressure gradient, stronger mid-level flow aloft, and terrain influences from the Sierra will promote winds of around 20 mph with gusts of around 30 mph. Very dry fuels (ERCs above the 90th percentile) in these areas will support rapid fire spread. ..Wendt.. 07/21/2025 ...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 0200 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN AND NORTH-CENTRAL NEVADA... ...Synopsis... With the base of the upper-level trough pivoting into the northern Great Basin today, a belt of stronger mid-level flow will stretch from northern California into northern Nevada and the northern Rockies. At the surface, a low in northeast Nevada/northern Utah will modestly deepen. ...Western/central Great Basin into western Wyoming... A relatively broad area of elevated fire weather is expected across much of the western/northern Great Basin into western Wyoming. RH will fall to 10-20% in Nevada while 15-20% will be more common farther north and east. Surface winds of 15-20 mph will develop by the afternoon. Critical fire weather is expected to occur in northwest and north-central Nevada. Here, the marginally stronger pressure gradient, stronger mid-level flow aloft, and terrain influences from the Sierra will promote winds of around 20 mph with gusts of around 30 mph. Very dry fuels (ERCs above the 90th percentile) in these areas will support rapid fire spread. ..Wendt.. 07/21/2025 ...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 0200 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN AND NORTH-CENTRAL NEVADA... ...Synopsis... With the base of the upper-level trough pivoting into the northern Great Basin today, a belt of stronger mid-level flow will stretch from northern California into northern Nevada and the northern Rockies. At the surface, a low in northeast Nevada/northern Utah will modestly deepen. ...Western/central Great Basin into western Wyoming... A relatively broad area of elevated fire weather is expected across much of the western/northern Great Basin into western Wyoming. RH will fall to 10-20% in Nevada while 15-20% will be more common farther north and east. Surface winds of 15-20 mph will develop by the afternoon. Critical fire weather is expected to occur in northwest and north-central Nevada. Here, the marginally stronger pressure gradient, stronger mid-level flow aloft, and terrain influences from the Sierra will promote winds of around 20 mph with gusts of around 30 mph. Very dry fuels (ERCs above the 90th percentile) in these areas will support rapid fire spread. ..Wendt.. 07/21/2025 ...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 0200 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN AND NORTH-CENTRAL NEVADA... ...Synopsis... With the base of the upper-level trough pivoting into the northern Great Basin today, a belt of stronger mid-level flow will stretch from northern California into northern Nevada and the northern Rockies. At the surface, a low in northeast Nevada/northern Utah will modestly deepen. ...Western/central Great Basin into western Wyoming... A relatively broad area of elevated fire weather is expected across much of the western/northern Great Basin into western Wyoming. RH will fall to 10-20% in Nevada while 15-20% will be more common farther north and east. Surface winds of 15-20 mph will develop by the afternoon. Critical fire weather is expected to occur in northwest and north-central Nevada. Here, the marginally stronger pressure gradient, stronger mid-level flow aloft, and terrain influences from the Sierra will promote winds of around 20 mph with gusts of around 30 mph. Very dry fuels (ERCs above the 90th percentile) in these areas will support rapid fire spread. ..Wendt.. 07/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NORTH DAKOTA...NORTHEASTERN SOUTH DAKOTA...MUCH OF CENTRAL MINNESOTA...AND ADJACENT NORTHWESTERN WISCONSIN... ...SUMMARY... Scattered strong thunderstorm development may impact parts of the northern Rockies and Great Plains into Upper Midwest Tuesday into Tuesday night, posing at least some risk for severe weather. ...Discussion... Models continue to indicate that an increasingly prominent mid-level high will evolve across parts of the middle Mississippi/lower Ohio Valley region during this period, within persistent ridging encompassing much of the interior U.S. Modest, anticyclonic flow around the northern periphery of the broader ridging is likely to be maintained across the northern Great Basin through the Dakotas and Upper Midwest, Great Lakes and adjacent portions of Ontario and Quebec. It appears that mid-level ridging will also remain prominent across much of the northeastern Pacific, though it may begin to undergo some suppression. Between the ridging, weak mid-level troughing is likely to linger across the Pacific coast vicinity. As one much more significant short wave trough and embedded cyclone in higher latitudes progress slowly toward the Hudson Bay vicinity, it still appears that one smaller-scale short wave perturbation emerging from the Pacific Northwest may accelerate across and northeast of the mountains of western Montana. However, models now generally indicate that a slightly stronger perturbation may linger to the southwest, across the northern intermountain region. In lower levels, a cold front trailing the higher latitude cyclone is forecast to advance across the international border into the northern Great Plains late Tuesday into Tuesday night. It appears another cold front may make further progress southward though the southern Atlantic coast vicinity, well south of the mid-latitude westerlies. ...Northern Rockies/Great Plains into Upper Midwest... Beneath the warm mid-level ridging, in the wake of a prior frontal passage, seasonably moist boundary layer air is forecast to surge from the middle Missouri Valley and adjacent Great Plains toward the Upper Midwest/adjacent Great Lakes, in advance of the front approaching from the Canadian Prairies. This moisture appears likely to once again contribute to moderate to large potential instability within modestly deep pre-frontal surface troughing, aided by insolation and the presence of generally steep tropospheric lapse rates, though with warm, capping layers aloft. Near the southern periphery of a belt of strengthening southwesterly mid-level flow, it still appears that this environment will become at least conditionally supportive of organized convective development. However, south of the international border, forcing for ascent to support convective development is likely to be mostly tied to subtle perturbations progressing around the northern periphery of the mid-level ridging, which remain uncertain at this time. There does appear a general consensus that stronger boundary-layer heating, within the lee surface troughing, will occur roughly in a narrow corridor from the western South Dakota/Nebraska state border vicinity through northeastern South Dakota/adjacent west central Minnesota by late afternoon, with a zone of strengthening differential heating extending east-southeastward across central Minnesota. It is possible that the boundary intersection could become a focus for isolated late afternoon supercell development, with warm advection along the zone of differential surface heating, aided by a strengthening southerly low-level jet impinging on it, contributing to an upscale growing cluster of storms Tuesday evening. However, due to the warm and capping air aloft, and possible weak upper support for ascent, this remains rather uncertain. With a more substantive short wave perturbation lingering back across the northern intermountain region, models suggest that more substantive destabilization is possible on moistening low-level northeasterly to easterly flow into the higher terrain of south central through southeastern Montana. Aided by the pronounced veering of winds from near surface to mid-levels, it appears that deep-layer shear may become conducive to isolated to widely scattered supercell development late Tuesday afternoon and evening. ...South Carolina into Georgia... Although lapse rates may be modest, high moisture content along/ahead of the slowly southwestward advancing cold front may support the development of modest CAPE and contribute to an environment conducive to convection capable of producing a few strong downbursts. It is also possible that unsaturated layers may be sufficient to contribute to broader cold pools accompanied by potentially damaging winds along the gust fronts. ..Kerr.. 07/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NORTH DAKOTA...NORTHEASTERN SOUTH DAKOTA...MUCH OF CENTRAL MINNESOTA...AND ADJACENT NORTHWESTERN WISCONSIN... ...SUMMARY... Scattered strong thunderstorm development may impact parts of the northern Rockies and Great Plains into Upper Midwest Tuesday into Tuesday night, posing at least some risk for severe weather. ...Discussion... Models continue to indicate that an increasingly prominent mid-level high will evolve across parts of the middle Mississippi/lower Ohio Valley region during this period, within persistent ridging encompassing much of the interior U.S. Modest, anticyclonic flow around the northern periphery of the broader ridging is likely to be maintained across the northern Great Basin through the Dakotas and Upper Midwest, Great Lakes and adjacent portions of Ontario and Quebec. It appears that mid-level ridging will also remain prominent across much of the northeastern Pacific, though it may begin to undergo some suppression. Between the ridging, weak mid-level troughing is likely to linger across the Pacific coast vicinity. As one much more significant short wave trough and embedded cyclone in higher latitudes progress slowly toward the Hudson Bay vicinity, it still appears that one smaller-scale short wave perturbation emerging from the Pacific Northwest may accelerate across and northeast of the mountains of western Montana. However, models now generally indicate that a slightly stronger perturbation may linger to the southwest, across the northern intermountain region. In lower levels, a cold front trailing the higher latitude cyclone is forecast to advance across the international border into the northern Great Plains late Tuesday into Tuesday night. It appears another cold front may make further progress southward though the southern Atlantic coast vicinity, well south of the mid-latitude westerlies. ...Northern Rockies/Great Plains into Upper Midwest... Beneath the warm mid-level ridging, in the wake of a prior frontal passage, seasonably moist boundary layer air is forecast to surge from the middle Missouri Valley and adjacent Great Plains toward the Upper Midwest/adjacent Great Lakes, in advance of the front approaching from the Canadian Prairies. This moisture appears likely to once again contribute to moderate to large potential instability within modestly deep pre-frontal surface troughing, aided by insolation and the presence of generally steep tropospheric lapse rates, though with warm, capping layers aloft. Near the southern periphery of a belt of strengthening southwesterly mid-level flow, it still appears that this environment will become at least conditionally supportive of organized convective development. However, south of the international border, forcing for ascent to support convective development is likely to be mostly tied to subtle perturbations progressing around the northern periphery of the mid-level ridging, which remain uncertain at this time. There does appear a general consensus that stronger boundary-layer heating, within the lee surface troughing, will occur roughly in a narrow corridor from the western South Dakota/Nebraska state border vicinity through northeastern South Dakota/adjacent west central Minnesota by late afternoon, with a zone of strengthening differential heating extending east-southeastward across central Minnesota. It is possible that the boundary intersection could become a focus for isolated late afternoon supercell development, with warm advection along the zone of differential surface heating, aided by a strengthening southerly low-level jet impinging on it, contributing to an upscale growing cluster of storms Tuesday evening. However, due to the warm and capping air aloft, and possible weak upper support for ascent, this remains rather uncertain. With a more substantive short wave perturbation lingering back across the northern intermountain region, models suggest that more substantive destabilization is possible on moistening low-level northeasterly to easterly flow into the higher terrain of south central through southeastern Montana. Aided by the pronounced veering of winds from near surface to mid-levels, it appears that deep-layer shear may become conducive to isolated to widely scattered supercell development late Tuesday afternoon and evening. ...South Carolina into Georgia... Although lapse rates may be modest, high moisture content along/ahead of the slowly southwestward advancing cold front may support the development of modest CAPE and contribute to an environment conducive to convection capable of producing a few strong downbursts. It is also possible that unsaturated layers may be sufficient to contribute to broader cold pools accompanied by potentially damaging winds along the gust fronts. ..Kerr.. 07/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NORTH DAKOTA...NORTHEASTERN SOUTH DAKOTA...MUCH OF CENTRAL MINNESOTA...AND ADJACENT NORTHWESTERN WISCONSIN... ...SUMMARY... Scattered strong thunderstorm development may impact parts of the northern Rockies and Great Plains into Upper Midwest Tuesday into Tuesday night, posing at least some risk for severe weather. ...Discussion... Models continue to indicate that an increasingly prominent mid-level high will evolve across parts of the middle Mississippi/lower Ohio Valley region during this period, within persistent ridging encompassing much of the interior U.S. Modest, anticyclonic flow around the northern periphery of the broader ridging is likely to be maintained across the northern Great Basin through the Dakotas and Upper Midwest, Great Lakes and adjacent portions of Ontario and Quebec. It appears that mid-level ridging will also remain prominent across much of the northeastern Pacific, though it may begin to undergo some suppression. Between the ridging, weak mid-level troughing is likely to linger across the Pacific coast vicinity. As one much more significant short wave trough and embedded cyclone in higher latitudes progress slowly toward the Hudson Bay vicinity, it still appears that one smaller-scale short wave perturbation emerging from the Pacific Northwest may accelerate across and northeast of the mountains of western Montana. However, models now generally indicate that a slightly stronger perturbation may linger to the southwest, across the northern intermountain region. In lower levels, a cold front trailing the higher latitude cyclone is forecast to advance across the international border into the northern Great Plains late Tuesday into Tuesday night. It appears another cold front may make further progress southward though the southern Atlantic coast vicinity, well south of the mid-latitude westerlies. ...Northern Rockies/Great Plains into Upper Midwest... Beneath the warm mid-level ridging, in the wake of a prior frontal passage, seasonably moist boundary layer air is forecast to surge from the middle Missouri Valley and adjacent Great Plains toward the Upper Midwest/adjacent Great Lakes, in advance of the front approaching from the Canadian Prairies. This moisture appears likely to once again contribute to moderate to large potential instability within modestly deep pre-frontal surface troughing, aided by insolation and the presence of generally steep tropospheric lapse rates, though with warm, capping layers aloft. Near the southern periphery of a belt of strengthening southwesterly mid-level flow, it still appears that this environment will become at least conditionally supportive of organized convective development. However, south of the international border, forcing for ascent to support convective development is likely to be mostly tied to subtle perturbations progressing around the northern periphery of the mid-level ridging, which remain uncertain at this time. There does appear a general consensus that stronger boundary-layer heating, within the lee surface troughing, will occur roughly in a narrow corridor from the western South Dakota/Nebraska state border vicinity through northeastern South Dakota/adjacent west central Minnesota by late afternoon, with a zone of strengthening differential heating extending east-southeastward across central Minnesota. It is possible that the boundary intersection could become a focus for isolated late afternoon supercell development, with warm advection along the zone of differential surface heating, aided by a strengthening southerly low-level jet impinging on it, contributing to an upscale growing cluster of storms Tuesday evening. However, due to the warm and capping air aloft, and possible weak upper support for ascent, this remains rather uncertain. With a more substantive short wave perturbation lingering back across the northern intermountain region, models suggest that more substantive destabilization is possible on moistening low-level northeasterly to easterly flow into the higher terrain of south central through southeastern Montana. Aided by the pronounced veering of winds from near surface to mid-levels, it appears that deep-layer shear may become conducive to isolated to widely scattered supercell development late Tuesday afternoon and evening. ...South Carolina into Georgia... Although lapse rates may be modest, high moisture content along/ahead of the slowly southwestward advancing cold front may support the development of modest CAPE and contribute to an environment conducive to convection capable of producing a few strong downbursts. It is also possible that unsaturated layers may be sufficient to contribute to broader cold pools accompanied by potentially damaging winds along the gust fronts. ..Kerr.. 07/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NORTH DAKOTA...NORTHEASTERN SOUTH DAKOTA...MUCH OF CENTRAL MINNESOTA...AND ADJACENT NORTHWESTERN WISCONSIN... ...SUMMARY... Scattered strong thunderstorm development may impact parts of the northern Rockies and Great Plains into Upper Midwest Tuesday into Tuesday night, posing at least some risk for severe weather. ...Discussion... Models continue to indicate that an increasingly prominent mid-level high will evolve across parts of the middle Mississippi/lower Ohio Valley region during this period, within persistent ridging encompassing much of the interior U.S. Modest, anticyclonic flow around the northern periphery of the broader ridging is likely to be maintained across the northern Great Basin through the Dakotas and Upper Midwest, Great Lakes and adjacent portions of Ontario and Quebec. It appears that mid-level ridging will also remain prominent across much of the northeastern Pacific, though it may begin to undergo some suppression. Between the ridging, weak mid-level troughing is likely to linger across the Pacific coast vicinity. As one much more significant short wave trough and embedded cyclone in higher latitudes progress slowly toward the Hudson Bay vicinity, it still appears that one smaller-scale short wave perturbation emerging from the Pacific Northwest may accelerate across and northeast of the mountains of western Montana. However, models now generally indicate that a slightly stronger perturbation may linger to the southwest, across the northern intermountain region. In lower levels, a cold front trailing the higher latitude cyclone is forecast to advance across the international border into the northern Great Plains late Tuesday into Tuesday night. It appears another cold front may make further progress southward though the southern Atlantic coast vicinity, well south of the mid-latitude westerlies. ...Northern Rockies/Great Plains into Upper Midwest... Beneath the warm mid-level ridging, in the wake of a prior frontal passage, seasonably moist boundary layer air is forecast to surge from the middle Missouri Valley and adjacent Great Plains toward the Upper Midwest/adjacent Great Lakes, in advance of the front approaching from the Canadian Prairies. This moisture appears likely to once again contribute to moderate to large potential instability within modestly deep pre-frontal surface troughing, aided by insolation and the presence of generally steep tropospheric lapse rates, though with warm, capping layers aloft. Near the southern periphery of a belt of strengthening southwesterly mid-level flow, it still appears that this environment will become at least conditionally supportive of organized convective development. However, south of the international border, forcing for ascent to support convective development is likely to be mostly tied to subtle perturbations progressing around the northern periphery of the mid-level ridging, which remain uncertain at this time. There does appear a general consensus that stronger boundary-layer heating, within the lee surface troughing, will occur roughly in a narrow corridor from the western South Dakota/Nebraska state border vicinity through northeastern South Dakota/adjacent west central Minnesota by late afternoon, with a zone of strengthening differential heating extending east-southeastward across central Minnesota. It is possible that the boundary intersection could become a focus for isolated late afternoon supercell development, with warm advection along the zone of differential surface heating, aided by a strengthening southerly low-level jet impinging on it, contributing to an upscale growing cluster of storms Tuesday evening. However, due to the warm and capping air aloft, and possible weak upper support for ascent, this remains rather uncertain. With a more substantive short wave perturbation lingering back across the northern intermountain region, models suggest that more substantive destabilization is possible on moistening low-level northeasterly to easterly flow into the higher terrain of south central through southeastern Montana. Aided by the pronounced veering of winds from near surface to mid-levels, it appears that deep-layer shear may become conducive to isolated to widely scattered supercell development late Tuesday afternoon and evening. ...South Carolina into Georgia... Although lapse rates may be modest, high moisture content along/ahead of the slowly southwestward advancing cold front may support the development of modest CAPE and contribute to an environment conducive to convection capable of producing a few strong downbursts. It is also possible that unsaturated layers may be sufficient to contribute to broader cold pools accompanied by potentially damaging winds along the gust fronts. ..Kerr.. 07/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1202 AM CDT Mon Jul 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF SOUTHEASTERN NORTH DAKOTA...NORTHEASTERN SOUTH DAKOTA...MUCH OF CENTRAL MINNESOTA...AND ADJACENT NORTHWESTERN WISCONSIN... ...SUMMARY... Scattered strong thunderstorm development may impact parts of the northern Rockies and Great Plains into Upper Midwest Tuesday into Tuesday night, posing at least some risk for severe weather. ...Discussion... Models continue to indicate that an increasingly prominent mid-level high will evolve across parts of the middle Mississippi/lower Ohio Valley region during this period, within persistent ridging encompassing much of the interior U.S. Modest, anticyclonic flow around the northern periphery of the broader ridging is likely to be maintained across the northern Great Basin through the Dakotas and Upper Midwest, Great Lakes and adjacent portions of Ontario and Quebec. It appears that mid-level ridging will also remain prominent across much of the northeastern Pacific, though it may begin to undergo some suppression. Between the ridging, weak mid-level troughing is likely to linger across the Pacific coast vicinity. As one much more significant short wave trough and embedded cyclone in higher latitudes progress slowly toward the Hudson Bay vicinity, it still appears that one smaller-scale short wave perturbation emerging from the Pacific Northwest may accelerate across and northeast of the mountains of western Montana. However, models now generally indicate that a slightly stronger perturbation may linger to the southwest, across the northern intermountain region. In lower levels, a cold front trailing the higher latitude cyclone is forecast to advance across the international border into the northern Great Plains late Tuesday into Tuesday night. It appears another cold front may make further progress southward though the southern Atlantic coast vicinity, well south of the mid-latitude westerlies. ...Northern Rockies/Great Plains into Upper Midwest... Beneath the warm mid-level ridging, in the wake of a prior frontal passage, seasonably moist boundary layer air is forecast to surge from the middle Missouri Valley and adjacent Great Plains toward the Upper Midwest/adjacent Great Lakes, in advance of the front approaching from the Canadian Prairies. This moisture appears likely to once again contribute to moderate to large potential instability within modestly deep pre-frontal surface troughing, aided by insolation and the presence of generally steep tropospheric lapse rates, though with warm, capping layers aloft. Near the southern periphery of a belt of strengthening southwesterly mid-level flow, it still appears that this environment will become at least conditionally supportive of organized convective development. However, south of the international border, forcing for ascent to support convective development is likely to be mostly tied to subtle perturbations progressing around the northern periphery of the mid-level ridging, which remain uncertain at this time. There does appear a general consensus that stronger boundary-layer heating, within the lee surface troughing, will occur roughly in a narrow corridor from the western South Dakota/Nebraska state border vicinity through northeastern South Dakota/adjacent west central Minnesota by late afternoon, with a zone of strengthening differential heating extending east-southeastward across central Minnesota. It is possible that the boundary intersection could become a focus for isolated late afternoon supercell development, with warm advection along the zone of differential surface heating, aided by a strengthening southerly low-level jet impinging on it, contributing to an upscale growing cluster of storms Tuesday evening. However, due to the warm and capping air aloft, and possible weak upper support for ascent, this remains rather uncertain. With a more substantive short wave perturbation lingering back across the northern intermountain region, models suggest that more substantive destabilization is possible on moistening low-level northeasterly to easterly flow into the higher terrain of south central through southeastern Montana. Aided by the pronounced veering of winds from near surface to mid-levels, it appears that deep-layer shear may become conducive to isolated to widely scattered supercell development late Tuesday afternoon and evening. ...South Carolina into Georgia... Although lapse rates may be modest, high moisture content along/ahead of the slowly southwestward advancing cold front may support the development of modest CAPE and contribute to an environment conducive to convection capable of producing a few strong downbursts. It is also possible that unsaturated layers may be sufficient to contribute to broader cold pools accompanied by potentially damaging winds along the gust fronts. ..Kerr.. 07/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF CENTRAL AND EASTERN MONTANA... ...SUMMARY... Severe thunderstorms capable of producing severe wind gusts, large hail, and perhaps a tornado or two are expected across parts of the northern Great Plains. Additional isolated strong to severe storms are possible in the central Plains. ...Synopsis... Modest amplification of an upper-level ridge is expected across the Plains into the Upper Midwest today. In the Northwest, the upper-level trough will take on a more neutral tilt before progressing eastward by Tuesday morning. At the surface, modest lee troughing will be in place within the northern/central High Plains regions. An outflow boundary is likely to be situated somewhere in the North Dakota/South Dakota border vicinity. Farther east into Minnesota, a warm front like feature will arc southeastward into the lower Ohio Valley. Strong to extreme buoyancy is forecast to develop within parts of the northern/central Plains. ...Montana into western North Dakota... The highest confidence in the development of severe storms is within the terrain of central Montana. Additional storms may develop in the vicinity of the Big Horns and move into southeast Montana. Mid-level heights will be rising through the morning/afternoon so initiation could be somewhat delayed. Subtle mid-level height falls will occur during the evening, however. With a belt of strong mid-level winds across the region, initial storms should be supercellular. Large hail and severe wind gusts will be the initial hazards. With storms developing in somewhat drier air, it is possible they will be outflow dominant and not maintain their cellular mode as they move northeast into greater moisture. The environment will be conditionally favorable for 2+ inch hail, but the spatial extent of this threat is not certain. Severe wind gusts will likely become more common later in the evening as activity grows upscale. ...Dakotas into Minnesota/Mid-Missouri Valley... Two clusters of convection are ongoing in the Dakotas. Based on current surface observations, this activity is expected to generally move eastward along the North Dakota/South Dakota border. What occurs with the outflow from this activity into this afternoon will play a role in the severe potential within parts of the Dakotas. Strong to extreme buoyancy will be present south of the outflow. Forcing for ascent will be weak. Storm development will depend on the timing of the early morning convection and subsequent heating/mesoscale lift during the afternoon. A weak surface low in western South Dakota may lead to some locally enhanced convergence along the outflow and trigger storms. This scenario is also not certain. Effective shear of 40-45 kts and MLCAPE likely above 4000 J/kg will support intense, organized storms. Initial storms would be capable large hail, severe winds, and perhaps a tornado or two. Storms that do develop would eventually grow upscale and potentially produce a swatch of severe winds. Model guidance varies on the timing/location of this activity. There is some potential for a cluster/MCS to propagate along the warm front feature into central Minnesota. Other solutions show the MCS moving into the greater buoyancy toward the Mid-Missouri Valley. Given some capping can be expected, storms may not develop at all. The marginal risk has been expanded to account for these possibilities, but confidence remains too low for a categorical upgrade at this time. ...Central High Plains... Strong heating near the surface trough should promote isolated to widely scattered storms from the Palmer Divide into the Nebraska Panhandle. Effective shear of 25-30 kts (generally weaker with southern extent) will allow for marginally organized storms. Severe wind gusts are the main concern as storms develop in the drier air. Some potential for large hail may also exist if storms can persist into greater moisture to the east. ..Wendt/Dean.. 07/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF CENTRAL AND EASTERN MONTANA... ...SUMMARY... Severe thunderstorms capable of producing severe wind gusts, large hail, and perhaps a tornado or two are expected across parts of the northern Great Plains. Additional isolated strong to severe storms are possible in the central Plains. ...Synopsis... Modest amplification of an upper-level ridge is expected across the Plains into the Upper Midwest today. In the Northwest, the upper-level trough will take on a more neutral tilt before progressing eastward by Tuesday morning. At the surface, modest lee troughing will be in place within the northern/central High Plains regions. An outflow boundary is likely to be situated somewhere in the North Dakota/South Dakota border vicinity. Farther east into Minnesota, a warm front like feature will arc southeastward into the lower Ohio Valley. Strong to extreme buoyancy is forecast to develop within parts of the northern/central Plains. ...Montana into western North Dakota... The highest confidence in the development of severe storms is within the terrain of central Montana. Additional storms may develop in the vicinity of the Big Horns and move into southeast Montana. Mid-level heights will be rising through the morning/afternoon so initiation could be somewhat delayed. Subtle mid-level height falls will occur during the evening, however. With a belt of strong mid-level winds across the region, initial storms should be supercellular. Large hail and severe wind gusts will be the initial hazards. With storms developing in somewhat drier air, it is possible they will be outflow dominant and not maintain their cellular mode as they move northeast into greater moisture. The environment will be conditionally favorable for 2+ inch hail, but the spatial extent of this threat is not certain. Severe wind gusts will likely become more common later in the evening as activity grows upscale. ...Dakotas into Minnesota/Mid-Missouri Valley... Two clusters of convection are ongoing in the Dakotas. Based on current surface observations, this activity is expected to generally move eastward along the North Dakota/South Dakota border. What occurs with the outflow from this activity into this afternoon will play a role in the severe potential within parts of the Dakotas. Strong to extreme buoyancy will be present south of the outflow. Forcing for ascent will be weak. Storm development will depend on the timing of the early morning convection and subsequent heating/mesoscale lift during the afternoon. A weak surface low in western South Dakota may lead to some locally enhanced convergence along the outflow and trigger storms. This scenario is also not certain. Effective shear of 40-45 kts and MLCAPE likely above 4000 J/kg will support intense, organized storms. Initial storms would be capable large hail, severe winds, and perhaps a tornado or two. Storms that do develop would eventually grow upscale and potentially produce a swatch of severe winds. Model guidance varies on the timing/location of this activity. There is some potential for a cluster/MCS to propagate along the warm front feature into central Minnesota. Other solutions show the MCS moving into the greater buoyancy toward the Mid-Missouri Valley. Given some capping can be expected, storms may not develop at all. The marginal risk has been expanded to account for these possibilities, but confidence remains too low for a categorical upgrade at this time. ...Central High Plains... Strong heating near the surface trough should promote isolated to widely scattered storms from the Palmer Divide into the Nebraska Panhandle. Effective shear of 25-30 kts (generally weaker with southern extent) will allow for marginally organized storms. Severe wind gusts are the main concern as storms develop in the drier air. Some potential for large hail may also exist if storms can persist into greater moisture to the east. ..Wendt/Dean.. 07/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF CENTRAL AND EASTERN MONTANA... ...SUMMARY... Severe thunderstorms capable of producing severe wind gusts, large hail, and perhaps a tornado or two are expected across parts of the northern Great Plains. Additional isolated strong to severe storms are possible in the central Plains. ...Synopsis... Modest amplification of an upper-level ridge is expected across the Plains into the Upper Midwest today. In the Northwest, the upper-level trough will take on a more neutral tilt before progressing eastward by Tuesday morning. At the surface, modest lee troughing will be in place within the northern/central High Plains regions. An outflow boundary is likely to be situated somewhere in the North Dakota/South Dakota border vicinity. Farther east into Minnesota, a warm front like feature will arc southeastward into the lower Ohio Valley. Strong to extreme buoyancy is forecast to develop within parts of the northern/central Plains. ...Montana into western North Dakota... The highest confidence in the development of severe storms is within the terrain of central Montana. Additional storms may develop in the vicinity of the Big Horns and move into southeast Montana. Mid-level heights will be rising through the morning/afternoon so initiation could be somewhat delayed. Subtle mid-level height falls will occur during the evening, however. With a belt of strong mid-level winds across the region, initial storms should be supercellular. Large hail and severe wind gusts will be the initial hazards. With storms developing in somewhat drier air, it is possible they will be outflow dominant and not maintain their cellular mode as they move northeast into greater moisture. The environment will be conditionally favorable for 2+ inch hail, but the spatial extent of this threat is not certain. Severe wind gusts will likely become more common later in the evening as activity grows upscale. ...Dakotas into Minnesota/Mid-Missouri Valley... Two clusters of convection are ongoing in the Dakotas. Based on current surface observations, this activity is expected to generally move eastward along the North Dakota/South Dakota border. What occurs with the outflow from this activity into this afternoon will play a role in the severe potential within parts of the Dakotas. Strong to extreme buoyancy will be present south of the outflow. Forcing for ascent will be weak. Storm development will depend on the timing of the early morning convection and subsequent heating/mesoscale lift during the afternoon. A weak surface low in western South Dakota may lead to some locally enhanced convergence along the outflow and trigger storms. This scenario is also not certain. Effective shear of 40-45 kts and MLCAPE likely above 4000 J/kg will support intense, organized storms. Initial storms would be capable large hail, severe winds, and perhaps a tornado or two. Storms that do develop would eventually grow upscale and potentially produce a swatch of severe winds. Model guidance varies on the timing/location of this activity. There is some potential for a cluster/MCS to propagate along the warm front feature into central Minnesota. Other solutions show the MCS moving into the greater buoyancy toward the Mid-Missouri Valley. Given some capping can be expected, storms may not develop at all. The marginal risk has been expanded to account for these possibilities, but confidence remains too low for a categorical upgrade at this time. ...Central High Plains... Strong heating near the surface trough should promote isolated to widely scattered storms from the Palmer Divide into the Nebraska Panhandle. Effective shear of 25-30 kts (generally weaker with southern extent) will allow for marginally organized storms. Severe wind gusts are the main concern as storms develop in the drier air. Some potential for large hail may also exist if storms can persist into greater moisture to the east. ..Wendt/Dean.. 07/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF CENTRAL AND EASTERN MONTANA... ...SUMMARY... Severe thunderstorms capable of producing severe wind gusts, large hail, and perhaps a tornado or two are expected across parts of the northern Great Plains. Additional isolated strong to severe storms are possible in the central Plains. ...Synopsis... Modest amplification of an upper-level ridge is expected across the Plains into the Upper Midwest today. In the Northwest, the upper-level trough will take on a more neutral tilt before progressing eastward by Tuesday morning. At the surface, modest lee troughing will be in place within the northern/central High Plains regions. An outflow boundary is likely to be situated somewhere in the North Dakota/South Dakota border vicinity. Farther east into Minnesota, a warm front like feature will arc southeastward into the lower Ohio Valley. Strong to extreme buoyancy is forecast to develop within parts of the northern/central Plains. ...Montana into western North Dakota... The highest confidence in the development of severe storms is within the terrain of central Montana. Additional storms may develop in the vicinity of the Big Horns and move into southeast Montana. Mid-level heights will be rising through the morning/afternoon so initiation could be somewhat delayed. Subtle mid-level height falls will occur during the evening, however. With a belt of strong mid-level winds across the region, initial storms should be supercellular. Large hail and severe wind gusts will be the initial hazards. With storms developing in somewhat drier air, it is possible they will be outflow dominant and not maintain their cellular mode as they move northeast into greater moisture. The environment will be conditionally favorable for 2+ inch hail, but the spatial extent of this threat is not certain. Severe wind gusts will likely become more common later in the evening as activity grows upscale. ...Dakotas into Minnesota/Mid-Missouri Valley... Two clusters of convection are ongoing in the Dakotas. Based on current surface observations, this activity is expected to generally move eastward along the North Dakota/South Dakota border. What occurs with the outflow from this activity into this afternoon will play a role in the severe potential within parts of the Dakotas. Strong to extreme buoyancy will be present south of the outflow. Forcing for ascent will be weak. Storm development will depend on the timing of the early morning convection and subsequent heating/mesoscale lift during the afternoon. A weak surface low in western South Dakota may lead to some locally enhanced convergence along the outflow and trigger storms. This scenario is also not certain. Effective shear of 40-45 kts and MLCAPE likely above 4000 J/kg will support intense, organized storms. Initial storms would be capable large hail, severe winds, and perhaps a tornado or two. Storms that do develop would eventually grow upscale and potentially produce a swatch of severe winds. Model guidance varies on the timing/location of this activity. There is some potential for a cluster/MCS to propagate along the warm front feature into central Minnesota. Other solutions show the MCS moving into the greater buoyancy toward the Mid-Missouri Valley. Given some capping can be expected, storms may not develop at all. The marginal risk has been expanded to account for these possibilities, but confidence remains too low for a categorical upgrade at this time. ...Central High Plains... Strong heating near the surface trough should promote isolated to widely scattered storms from the Palmer Divide into the Nebraska Panhandle. Effective shear of 25-30 kts (generally weaker with southern extent) will allow for marginally organized storms. Severe wind gusts are the main concern as storms develop in the drier air. Some potential for large hail may also exist if storms can persist into greater moisture to the east. ..Wendt/Dean.. 07/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Mon Jul 21 2025 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF CENTRAL AND EASTERN MONTANA... ...SUMMARY... Severe thunderstorms capable of producing severe wind gusts, large hail, and perhaps a tornado or two are expected across parts of the northern Great Plains. Additional isolated strong to severe storms are possible in the central Plains. ...Synopsis... Modest amplification of an upper-level ridge is expected across the Plains into the Upper Midwest today. In the Northwest, the upper-level trough will take on a more neutral tilt before progressing eastward by Tuesday morning. At the surface, modest lee troughing will be in place within the northern/central High Plains regions. An outflow boundary is likely to be situated somewhere in the North Dakota/South Dakota border vicinity. Farther east into Minnesota, a warm front like feature will arc southeastward into the lower Ohio Valley. Strong to extreme buoyancy is forecast to develop within parts of the northern/central Plains. ...Montana into western North Dakota... The highest confidence in the development of severe storms is within the terrain of central Montana. Additional storms may develop in the vicinity of the Big Horns and move into southeast Montana. Mid-level heights will be rising through the morning/afternoon so initiation could be somewhat delayed. Subtle mid-level height falls will occur during the evening, however. With a belt of strong mid-level winds across the region, initial storms should be supercellular. Large hail and severe wind gusts will be the initial hazards. With storms developing in somewhat drier air, it is possible they will be outflow dominant and not maintain their cellular mode as they move northeast into greater moisture. The environment will be conditionally favorable for 2+ inch hail, but the spatial extent of this threat is not certain. Severe wind gusts will likely become more common later in the evening as activity grows upscale. ...Dakotas into Minnesota/Mid-Missouri Valley... Two clusters of convection are ongoing in the Dakotas. Based on current surface observations, this activity is expected to generally move eastward along the North Dakota/South Dakota border. What occurs with the outflow from this activity into this afternoon will play a role in the severe potential within parts of the Dakotas. Strong to extreme buoyancy will be present south of the outflow. Forcing for ascent will be weak. Storm development will depend on the timing of the early morning convection and subsequent heating/mesoscale lift during the afternoon. A weak surface low in western South Dakota may lead to some locally enhanced convergence along the outflow and trigger storms. This scenario is also not certain. Effective shear of 40-45 kts and MLCAPE likely above 4000 J/kg will support intense, organized storms. Initial storms would be capable large hail, severe winds, and perhaps a tornado or two. Storms that do develop would eventually grow upscale and potentially produce a swatch of severe winds. Model guidance varies on the timing/location of this activity. There is some potential for a cluster/MCS to propagate along the warm front feature into central Minnesota. Other solutions show the MCS moving into the greater buoyancy toward the Mid-Missouri Valley. Given some capping can be expected, storms may not develop at all. The marginal risk has been expanded to account for these possibilities, but confidence remains too low for a categorical upgrade at this time. ...Central High Plains... Strong heating near the surface trough should promote isolated to widely scattered storms from the Palmer Divide into the Nebraska Panhandle. Effective shear of 25-30 kts (generally weaker with southern extent) will allow for marginally organized storms. Severe wind gusts are the main concern as storms develop in the drier air. Some potential for large hail may also exist if storms can persist into greater moisture to the east. ..Wendt/Dean.. 07/21/2025 Read more

WW 0531 Status Updates
STATUS REPORT ON WW 531 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 E 2WX TO Y22. ..BENTLEY..07/21/25 ATTN...WFO...BYZ...GGW...BIS... STATUS REPORT FOR WS 531 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC037-085-210640- ND . NORTH DAKOTA COUNTIES INCLUDED ARE GRANT SIOUX THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 531 SEVERE TSTM MT ND 202210Z - 210600Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 531 NWS Storm Prediction Center Norman OK 410 PM MDT Sun Jul 20 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southeast Montana Southwest North Dakota * Effective this Sunday afternoon from 410 PM until Midnight MDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Multiple clusters of thunderstorms will affect the watch area through the evening, including a few supercells. Damaging winds and large hail are the main concerns. The severe thunderstorm watch area is approximately along and 75 statute miles north and south of a line from 65 miles west of Miles City MT to 20 miles east of Dickinson ND. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 530... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27030. ...Hart Read more

WW 0534 Status Updates
STATUS REPORT ON WW 534 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 60 SW 2WX TO 25 SW 2WX TO 40 ENE Y22. ..BENTLEY..07/21/25 ATTN...WFO...UNR... STATUS REPORT FOR WS 534 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC019-063-093-105-137-210640- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUTTE HARDING MEADE PERKINS ZIEBACH THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more