Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Mon Aug 04 2025 Valid 041630Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE HIGH PLAINS... ...SUMMARY... Thunderstorms with severe gusts and large to very large hail will be possible this afternoon through this evening from parts of the northern Rockies into the Dakotas and central/southern High Plains. ...Central High Plains... An upper ridge extending from NM north-northeastward into the central High Plains will feature a couple of weak disturbances cresting the ridge through early Tuesday morning. The most notable disturbance over northeast UT late this morning is forecast to move east across southern WY by early evening and potentially play a role in storm development late this afternoon/evening. A seasonably moist airmass featuring 55-60 deg F dewpoints into eastern WY/NE Panhandle will undergo strong heating. Low-level southeasterly flow will veer to northwesterly in the mid levels, resulting in moderate to strong deep-layer vertical shear and an overall wind profile that favors supercells. As such, there is conditional risk for severe thunderstorms. However, the forcing mechanism for convective initiation is fairly weak. The general expectation is that low-level convergence and upslope flow across the Black Hills vicinity should be enough for scattered convective initiation with other widely scattered storms possible farther south. The environment supports supercells capable of large to very large hail and severe gusts. Any supercells that develop could last for a few hours, but should eventually trend towards a more linear mode with one or more clusters evolving across western/central NE and northeast CO this evening. Aided by a 40+ kt low-level jet, continued upscale growth should support these clusters of strong to severe storms into the overnight hours where damaging winds will be possible. ...Northern Rockies into eastern Montana... Water-vapor imagery shows a potent mid- to upper-level shortwave trough moving east across OR this morning. This disturbance is forecast to move into the northern Rockies by early evening and into the northern High Plains by daybreak. Strong large-scale ascent associated with this shortwave trough as it acquires a negative tilt, will favor isolated to scattered storms from the Snake Valley northward into north-central ID and into western/southwest MT. Initially cellular storms will pose an isolated risk for severe wind gusts. As storms move into the high plains, slightly greater low-level moisture will aid in more numerous storms developing and their attendant outflow. Scattered severe gusts (60-75 mph) are possible with this activity as it moves east-northeast across MT. ...Southern High Plains... Strong heating along a lee trough could support isolated to widely scattered thunderstorm development from the Raton Mesa into southeast CO/northeast NM. Ample high-level flow atop strongly veering low-level winds, coupled with a very unstable airmass on the western periphery of rich moisture, will favor the possibility for a few supercells by late afternoon. Large to very large hail, severe gusts, and a brief tornado are the potential hazards. Some guidance shows a cluster evolving during the evening with severe gusts becoming the primary hazard. ...Central/Southeast Texas... A weakening squall line will continue southward to the middle TX coast over the next couple of hours with other weak thunderstorm activity perhaps lingering atop the cold pool. Isolated strong gusts will probably become increasingly localized during the midday. ..Smith/Wendt.. 08/04/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Mon Aug 04 2025 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms with severe gusts and hail will be possible today and tonight from parts of the northern Rockies into the Dakotas and central/southern High Plains. ...Central High Plains... Early morning surface analysis shows upper 50s dewpoints in place across eastern CO, western KS, and western NE, with slightly lower dewpoints across the NE Panhandle. Moist, southerly low-level flow will help increase dewpoints across the region throughout the day, likely resulting in upper 50s to low 60s dewpoints during the afternoon despite strong heating and boundary-layer mixing. This should result in a strongly buoyant but minimally capped airmass across the region by the late afternoon. Additionally, low-level southeasterly flow will veer to northwesterly in the mid levels, resulting in moderate to strong deep-layer vertical shear and an overall wind profile that favors supercells. As such, there is conditional risk for severe thunderstorms. However, the forcing mechanism for convective initiation is uncertain. Upper ridging that currently extends from the Southwest into the northern High Plains is expected to persist throughout the day, with heights likely rising across the central High Plains. A shortwave trough currently moving through the Great Basin is expected to move within the northern periphery of this ridging, reaching the central Rockies by this afternoon. Even so, given that heights are forecast to rise across the central High Plains, the downstream influence of this wave into the central High Plains will likely be minimal. This overall lack of larger scale ascent leads to uncertainty regarding storm coverage since more mesoscale factors, such as low-level convergence along the lee troughing and weak low-level upslope flow, will be the mechanisms for convective initiation. High-resolution guidance offers varied storm coverage, with more recent HRRR runs (i.e. 06-08Z) keeping the area largely free of storms versus earlier runs (i.e. 00Z) which show scattered coverage. However, these drier and less convective HRRR runs appear to be outliers compared to all the other available guidance, and the general expectation is that low-level convergence and upslope flow across the Black Hill vicinity should be enough for scattered convective initiation. As mentioned previously, the overall environment supports supercells capable of large to very large hail and strong gusts. Any supercells that develop could last for a few hours, but should eventually trend towards a more linear mode with one or more clusters evolving across western/central NE and northeast CO this evening. Aided by a 40+ kt low-level jet, continued upscale growth should support these clusters of strong to severe storms into the overnight hours where damaging winds will be possible. ...Northern Rockies into eastern Montana... Shortwave trough currently moving through southern OR is forecast to continue northeastward through the northern Rockies today and tonight, while becoming increasingly negatively tilted. Ascent attendant to this wave will interact with a modest buoyant airmass from central ID into central MT, resulting in scattered to numerous thunderstorms across the region. Initially more cellular storms are expected across the higher terrain of central ID and western MT with eventual cold pool amalgamation resulting in one or two eastward/northeastward progressing clusters across central and eastern MT. Some hail is possible with the more cellular storms, but damaging gusts appear to be the greater severe risk. Sufficient severe storm coverage is anticipated across central and eastern MT to merit introducing 15% wind probabilities. ...Southern High Plains... Strong heating along a lee trough could support isolated thunderstorm development from the Raton Mesa into southeast CO/northeast NM. The thermodynamic environment here will be similar to areas farther north, with large buoyancy (3000+ J/kg MLCAPE) and 40-50 kt of effective shear anticipated. A supercell mode is expected initially with any storms that mature, with large hail, damaging gusts, and a brief tornado possible. Storm maintenance into the OK/TX Panhandles is possible, particularly given the strengthening low-level jet. ...Central/Southeast Texas... A decaying MCS continues to push southward/southeastward across central TX at 35 kt. Isolated damaging gusts will remain possible with this system over the next hour or two, but warming cloud tops and lowering echo tops suggest this system will continue to weaken. Additional storm development is possible along the western portion of the outflow, but low-level stability should mitigate updraft strength. ..Mosier/Bentley.. 08/04/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Mon Aug 04 2025 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms with severe gusts and hail will be possible today and tonight from parts of the northern Rockies into the Dakotas and central/southern High Plains. ...Central High Plains... Early morning surface analysis shows upper 50s dewpoints in place across eastern CO, western KS, and western NE, with slightly lower dewpoints across the NE Panhandle. Moist, southerly low-level flow will help increase dewpoints across the region throughout the day, likely resulting in upper 50s to low 60s dewpoints during the afternoon despite strong heating and boundary-layer mixing. This should result in a strongly buoyant but minimally capped airmass across the region by the late afternoon. Additionally, low-level southeasterly flow will veer to northwesterly in the mid levels, resulting in moderate to strong deep-layer vertical shear and an overall wind profile that favors supercells. As such, there is conditional risk for severe thunderstorms. However, the forcing mechanism for convective initiation is uncertain. Upper ridging that currently extends from the Southwest into the northern High Plains is expected to persist throughout the day, with heights likely rising across the central High Plains. A shortwave trough currently moving through the Great Basin is expected to move within the northern periphery of this ridging, reaching the central Rockies by this afternoon. Even so, given that heights are forecast to rise across the central High Plains, the downstream influence of this wave into the central High Plains will likely be minimal. This overall lack of larger scale ascent leads to uncertainty regarding storm coverage since more mesoscale factors, such as low-level convergence along the lee troughing and weak low-level upslope flow, will be the mechanisms for convective initiation. High-resolution guidance offers varied storm coverage, with more recent HRRR runs (i.e. 06-08Z) keeping the area largely free of storms versus earlier runs (i.e. 00Z) which show scattered coverage. However, these drier and less convective HRRR runs appear to be outliers compared to all the other available guidance, and the general expectation is that low-level convergence and upslope flow across the Black Hill vicinity should be enough for scattered convective initiation. As mentioned previously, the overall environment supports supercells capable of large to very large hail and strong gusts. Any supercells that develop could last for a few hours, but should eventually trend towards a more linear mode with one or more clusters evolving across western/central NE and northeast CO this evening. Aided by a 40+ kt low-level jet, continued upscale growth should support these clusters of strong to severe storms into the overnight hours where damaging winds will be possible. ...Northern Rockies into eastern Montana... Shortwave trough currently moving through southern OR is forecast to continue northeastward through the northern Rockies today and tonight, while becoming increasingly negatively tilted. Ascent attendant to this wave will interact with a modest buoyant airmass from central ID into central MT, resulting in scattered to numerous thunderstorms across the region. Initially more cellular storms are expected across the higher terrain of central ID and western MT with eventual cold pool amalgamation resulting in one or two eastward/northeastward progressing clusters across central and eastern MT. Some hail is possible with the more cellular storms, but damaging gusts appear to be the greater severe risk. Sufficient severe storm coverage is anticipated across central and eastern MT to merit introducing 15% wind probabilities. ...Southern High Plains... Strong heating along a lee trough could support isolated thunderstorm development from the Raton Mesa into southeast CO/northeast NM. The thermodynamic environment here will be similar to areas farther north, with large buoyancy (3000+ J/kg MLCAPE) and 40-50 kt of effective shear anticipated. A supercell mode is expected initially with any storms that mature, with large hail, damaging gusts, and a brief tornado possible. Storm maintenance into the OK/TX Panhandles is possible, particularly given the strengthening low-level jet. ...Central/Southeast Texas... A decaying MCS continues to push southward/southeastward across central TX at 35 kt. Isolated damaging gusts will remain possible with this system over the next hour or two, but warming cloud tops and lowering echo tops suggest this system will continue to weaken. Additional storm development is possible along the western portion of the outflow, but low-level stability should mitigate updraft strength. ..Mosier/Bentley.. 08/04/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Mon Aug 04 2025 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms with severe gusts and hail will be possible today and tonight from parts of the northern Rockies into the Dakotas and central/southern High Plains. ...Central High Plains... Early morning surface analysis shows upper 50s dewpoints in place across eastern CO, western KS, and western NE, with slightly lower dewpoints across the NE Panhandle. Moist, southerly low-level flow will help increase dewpoints across the region throughout the day, likely resulting in upper 50s to low 60s dewpoints during the afternoon despite strong heating and boundary-layer mixing. This should result in a strongly buoyant but minimally capped airmass across the region by the late afternoon. Additionally, low-level southeasterly flow will veer to northwesterly in the mid levels, resulting in moderate to strong deep-layer vertical shear and an overall wind profile that favors supercells. As such, there is conditional risk for severe thunderstorms. However, the forcing mechanism for convective initiation is uncertain. Upper ridging that currently extends from the Southwest into the northern High Plains is expected to persist throughout the day, with heights likely rising across the central High Plains. A shortwave trough currently moving through the Great Basin is expected to move within the northern periphery of this ridging, reaching the central Rockies by this afternoon. Even so, given that heights are forecast to rise across the central High Plains, the downstream influence of this wave into the central High Plains will likely be minimal. This overall lack of larger scale ascent leads to uncertainty regarding storm coverage since more mesoscale factors, such as low-level convergence along the lee troughing and weak low-level upslope flow, will be the mechanisms for convective initiation. High-resolution guidance offers varied storm coverage, with more recent HRRR runs (i.e. 06-08Z) keeping the area largely free of storms versus earlier runs (i.e. 00Z) which show scattered coverage. However, these drier and less convective HRRR runs appear to be outliers compared to all the other available guidance, and the general expectation is that low-level convergence and upslope flow across the Black Hill vicinity should be enough for scattered convective initiation. As mentioned previously, the overall environment supports supercells capable of large to very large hail and strong gusts. Any supercells that develop could last for a few hours, but should eventually trend towards a more linear mode with one or more clusters evolving across western/central NE and northeast CO this evening. Aided by a 40+ kt low-level jet, continued upscale growth should support these clusters of strong to severe storms into the overnight hours where damaging winds will be possible. ...Northern Rockies into eastern Montana... Shortwave trough currently moving through southern OR is forecast to continue northeastward through the northern Rockies today and tonight, while becoming increasingly negatively tilted. Ascent attendant to this wave will interact with a modest buoyant airmass from central ID into central MT, resulting in scattered to numerous thunderstorms across the region. Initially more cellular storms are expected across the higher terrain of central ID and western MT with eventual cold pool amalgamation resulting in one or two eastward/northeastward progressing clusters across central and eastern MT. Some hail is possible with the more cellular storms, but damaging gusts appear to be the greater severe risk. Sufficient severe storm coverage is anticipated across central and eastern MT to merit introducing 15% wind probabilities. ...Southern High Plains... Strong heating along a lee trough could support isolated thunderstorm development from the Raton Mesa into southeast CO/northeast NM. The thermodynamic environment here will be similar to areas farther north, with large buoyancy (3000+ J/kg MLCAPE) and 40-50 kt of effective shear anticipated. A supercell mode is expected initially with any storms that mature, with large hail, damaging gusts, and a brief tornado possible. Storm maintenance into the OK/TX Panhandles is possible, particularly given the strengthening low-level jet. ...Central/Southeast Texas... A decaying MCS continues to push southward/southeastward across central TX at 35 kt. Isolated damaging gusts will remain possible with this system over the next hour or two, but warming cloud tops and lowering echo tops suggest this system will continue to weaken. Additional storm development is possible along the western portion of the outflow, but low-level stability should mitigate updraft strength. ..Mosier/Bentley.. 08/04/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Mon Aug 04 2025 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms with severe gusts and hail will be possible today and tonight from parts of the northern Rockies into the Dakotas and central/southern High Plains. ...Central High Plains... Early morning surface analysis shows upper 50s dewpoints in place across eastern CO, western KS, and western NE, with slightly lower dewpoints across the NE Panhandle. Moist, southerly low-level flow will help increase dewpoints across the region throughout the day, likely resulting in upper 50s to low 60s dewpoints during the afternoon despite strong heating and boundary-layer mixing. This should result in a strongly buoyant but minimally capped airmass across the region by the late afternoon. Additionally, low-level southeasterly flow will veer to northwesterly in the mid levels, resulting in moderate to strong deep-layer vertical shear and an overall wind profile that favors supercells. As such, there is conditional risk for severe thunderstorms. However, the forcing mechanism for convective initiation is uncertain. Upper ridging that currently extends from the Southwest into the northern High Plains is expected to persist throughout the day, with heights likely rising across the central High Plains. A shortwave trough currently moving through the Great Basin is expected to move within the northern periphery of this ridging, reaching the central Rockies by this afternoon. Even so, given that heights are forecast to rise across the central High Plains, the downstream influence of this wave into the central High Plains will likely be minimal. This overall lack of larger scale ascent leads to uncertainty regarding storm coverage since more mesoscale factors, such as low-level convergence along the lee troughing and weak low-level upslope flow, will be the mechanisms for convective initiation. High-resolution guidance offers varied storm coverage, with more recent HRRR runs (i.e. 06-08Z) keeping the area largely free of storms versus earlier runs (i.e. 00Z) which show scattered coverage. However, these drier and less convective HRRR runs appear to be outliers compared to all the other available guidance, and the general expectation is that low-level convergence and upslope flow across the Black Hill vicinity should be enough for scattered convective initiation. As mentioned previously, the overall environment supports supercells capable of large to very large hail and strong gusts. Any supercells that develop could last for a few hours, but should eventually trend towards a more linear mode with one or more clusters evolving across western/central NE and northeast CO this evening. Aided by a 40+ kt low-level jet, continued upscale growth should support these clusters of strong to severe storms into the overnight hours where damaging winds will be possible. ...Northern Rockies into eastern Montana... Shortwave trough currently moving through southern OR is forecast to continue northeastward through the northern Rockies today and tonight, while becoming increasingly negatively tilted. Ascent attendant to this wave will interact with a modest buoyant airmass from central ID into central MT, resulting in scattered to numerous thunderstorms across the region. Initially more cellular storms are expected across the higher terrain of central ID and western MT with eventual cold pool amalgamation resulting in one or two eastward/northeastward progressing clusters across central and eastern MT. Some hail is possible with the more cellular storms, but damaging gusts appear to be the greater severe risk. Sufficient severe storm coverage is anticipated across central and eastern MT to merit introducing 15% wind probabilities. ...Southern High Plains... Strong heating along a lee trough could support isolated thunderstorm development from the Raton Mesa into southeast CO/northeast NM. The thermodynamic environment here will be similar to areas farther north, with large buoyancy (3000+ J/kg MLCAPE) and 40-50 kt of effective shear anticipated. A supercell mode is expected initially with any storms that mature, with large hail, damaging gusts, and a brief tornado possible. Storm maintenance into the OK/TX Panhandles is possible, particularly given the strengthening low-level jet. ...Central/Southeast Texas... A decaying MCS continues to push southward/southeastward across central TX at 35 kt. Isolated damaging gusts will remain possible with this system over the next hour or two, but warming cloud tops and lowering echo tops suggest this system will continue to weaken. Additional storm development is possible along the western portion of the outflow, but low-level stability should mitigate updraft strength. ..Mosier/Bentley.. 08/04/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0403 AM CDT Mon Aug 04 2025 Valid 071200Z - 121200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... During the late week time-frame, a mid-level trough is forecast to develop over the Pacific Northwest and move eastward into the northern Plains. As the system approaches, a moist and unstable airmass is forecast across the northern Plains and upper Mississippi Valley. On Thursday, a lead shortwave trough is forecast to move across the northern Plains. Large-scale ascent associated with the trough could result in a cluster of storms with an isolated severe threat from Thursday evening into the overnight period. Isolated to scattered thunderstorms may again develop Friday afternoon and evening, as the exit region of a mid-level jet moves across the northern Plains. As instability becomes maximized on Friday afternoon, a severe threat will be possible across parts of the Dakotas and Minnesota. Large hail and severe gusts will be the primary threats. The models are in reasonably good agreement on the timing of the mid-level system. For this reason, have added a 15 percent into the northern Plains to coincide with the projected locations of the instability axis and mid-level jet. On Saturday, the mid-level trough is forecast to move into the northern Plains, as a belt of southwesterly flow shifts eastward across the Upper Midwest. Thunderstorm development will be possible in the afternoon and evening, to the east of a front within an unstable airmass in the upper Mississippi Valley. Moderate deep-layer shear will again support an isolated severe threat across the region. ...Sunday/Day 7 and Monday/Day 8... The front is forecast to move southeastward into the upper Mississippi Valley on Sunday. This will favor thunderstorm development along a corridor from Iowa northeastward into Wisconsin, where an isolated severe threat will be possible in the afternoon and evening. On Monday, forecasts suggest the instability axis will remain in a similar location. For this reason, a severe threat could again affect this same corridor. Due to the extended range in the forecast, there is some uncertainty concerning this scenario early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0403 AM CDT Mon Aug 04 2025 Valid 071200Z - 121200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... During the late week time-frame, a mid-level trough is forecast to develop over the Pacific Northwest and move eastward into the northern Plains. As the system approaches, a moist and unstable airmass is forecast across the northern Plains and upper Mississippi Valley. On Thursday, a lead shortwave trough is forecast to move across the northern Plains. Large-scale ascent associated with the trough could result in a cluster of storms with an isolated severe threat from Thursday evening into the overnight period. Isolated to scattered thunderstorms may again develop Friday afternoon and evening, as the exit region of a mid-level jet moves across the northern Plains. As instability becomes maximized on Friday afternoon, a severe threat will be possible across parts of the Dakotas and Minnesota. Large hail and severe gusts will be the primary threats. The models are in reasonably good agreement on the timing of the mid-level system. For this reason, have added a 15 percent into the northern Plains to coincide with the projected locations of the instability axis and mid-level jet. On Saturday, the mid-level trough is forecast to move into the northern Plains, as a belt of southwesterly flow shifts eastward across the Upper Midwest. Thunderstorm development will be possible in the afternoon and evening, to the east of a front within an unstable airmass in the upper Mississippi Valley. Moderate deep-layer shear will again support an isolated severe threat across the region. ...Sunday/Day 7 and Monday/Day 8... The front is forecast to move southeastward into the upper Mississippi Valley on Sunday. This will favor thunderstorm development along a corridor from Iowa northeastward into Wisconsin, where an isolated severe threat will be possible in the afternoon and evening. On Monday, forecasts suggest the instability axis will remain in a similar location. For this reason, a severe threat could again affect this same corridor. Due to the extended range in the forecast, there is some uncertainty concerning this scenario early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0403 AM CDT Mon Aug 04 2025 Valid 071200Z - 121200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... During the late week time-frame, a mid-level trough is forecast to develop over the Pacific Northwest and move eastward into the northern Plains. As the system approaches, a moist and unstable airmass is forecast across the northern Plains and upper Mississippi Valley. On Thursday, a lead shortwave trough is forecast to move across the northern Plains. Large-scale ascent associated with the trough could result in a cluster of storms with an isolated severe threat from Thursday evening into the overnight period. Isolated to scattered thunderstorms may again develop Friday afternoon and evening, as the exit region of a mid-level jet moves across the northern Plains. As instability becomes maximized on Friday afternoon, a severe threat will be possible across parts of the Dakotas and Minnesota. Large hail and severe gusts will be the primary threats. The models are in reasonably good agreement on the timing of the mid-level system. For this reason, have added a 15 percent into the northern Plains to coincide with the projected locations of the instability axis and mid-level jet. On Saturday, the mid-level trough is forecast to move into the northern Plains, as a belt of southwesterly flow shifts eastward across the Upper Midwest. Thunderstorm development will be possible in the afternoon and evening, to the east of a front within an unstable airmass in the upper Mississippi Valley. Moderate deep-layer shear will again support an isolated severe threat across the region. ...Sunday/Day 7 and Monday/Day 8... The front is forecast to move southeastward into the upper Mississippi Valley on Sunday. This will favor thunderstorm development along a corridor from Iowa northeastward into Wisconsin, where an isolated severe threat will be possible in the afternoon and evening. On Monday, forecasts suggest the instability axis will remain in a similar location. For this reason, a severe threat could again affect this same corridor. Due to the extended range in the forecast, there is some uncertainty concerning this scenario early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0403 AM CDT Mon Aug 04 2025 Valid 071200Z - 121200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... During the late week time-frame, a mid-level trough is forecast to develop over the Pacific Northwest and move eastward into the northern Plains. As the system approaches, a moist and unstable airmass is forecast across the northern Plains and upper Mississippi Valley. On Thursday, a lead shortwave trough is forecast to move across the northern Plains. Large-scale ascent associated with the trough could result in a cluster of storms with an isolated severe threat from Thursday evening into the overnight period. Isolated to scattered thunderstorms may again develop Friday afternoon and evening, as the exit region of a mid-level jet moves across the northern Plains. As instability becomes maximized on Friday afternoon, a severe threat will be possible across parts of the Dakotas and Minnesota. Large hail and severe gusts will be the primary threats. The models are in reasonably good agreement on the timing of the mid-level system. For this reason, have added a 15 percent into the northern Plains to coincide with the projected locations of the instability axis and mid-level jet. On Saturday, the mid-level trough is forecast to move into the northern Plains, as a belt of southwesterly flow shifts eastward across the Upper Midwest. Thunderstorm development will be possible in the afternoon and evening, to the east of a front within an unstable airmass in the upper Mississippi Valley. Moderate deep-layer shear will again support an isolated severe threat across the region. ...Sunday/Day 7 and Monday/Day 8... The front is forecast to move southeastward into the upper Mississippi Valley on Sunday. This will favor thunderstorm development along a corridor from Iowa northeastward into Wisconsin, where an isolated severe threat will be possible in the afternoon and evening. On Monday, forecasts suggest the instability axis will remain in a similar location. For this reason, a severe threat could again affect this same corridor. Due to the extended range in the forecast, there is some uncertainty concerning this scenario early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0403 AM CDT Mon Aug 04 2025 Valid 071200Z - 121200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... During the late week time-frame, a mid-level trough is forecast to develop over the Pacific Northwest and move eastward into the northern Plains. As the system approaches, a moist and unstable airmass is forecast across the northern Plains and upper Mississippi Valley. On Thursday, a lead shortwave trough is forecast to move across the northern Plains. Large-scale ascent associated with the trough could result in a cluster of storms with an isolated severe threat from Thursday evening into the overnight period. Isolated to scattered thunderstorms may again develop Friday afternoon and evening, as the exit region of a mid-level jet moves across the northern Plains. As instability becomes maximized on Friday afternoon, a severe threat will be possible across parts of the Dakotas and Minnesota. Large hail and severe gusts will be the primary threats. The models are in reasonably good agreement on the timing of the mid-level system. For this reason, have added a 15 percent into the northern Plains to coincide with the projected locations of the instability axis and mid-level jet. On Saturday, the mid-level trough is forecast to move into the northern Plains, as a belt of southwesterly flow shifts eastward across the Upper Midwest. Thunderstorm development will be possible in the afternoon and evening, to the east of a front within an unstable airmass in the upper Mississippi Valley. Moderate deep-layer shear will again support an isolated severe threat across the region. ...Sunday/Day 7 and Monday/Day 8... The front is forecast to move southeastward into the upper Mississippi Valley on Sunday. This will favor thunderstorm development along a corridor from Iowa northeastward into Wisconsin, where an isolated severe threat will be possible in the afternoon and evening. On Monday, forecasts suggest the instability axis will remain in a similar location. For this reason, a severe threat could again affect this same corridor. Due to the extended range in the forecast, there is some uncertainty concerning this scenario early next week. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0216 AM CDT Mon Aug 04 2025 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTH-CENTRAL U.S.... ...SUMMARY... Isolated thunderstorms associated with severe gusts and hail will be possible across parts of the north-central U.S. on Wednesday. ...Central and Northern Plains/Upper Mississippi Valley... A large-scale anticyclonic flow pattern is forecast across the central and northern U.S. on Wednesday. At the surface, a moist airmass should be located from the Great Plains into the Mississippi Valley. As surface temperatures warm on Wednesday, moderate instability is expected to develop across much of the moist airmass. Due to the anticyclonic flow pattern and lack of any shortwave trough, large-scale ascent is forecast to remain weak over much of the north-central U.S. In spite of this, isolated thunderstorms may develop in areas that heat up that most, or along pre-existing boundaries. For cells that initiate and persist, deep-layer shear may be strong enough for an isolated severe threat. A few severe gusts and hail will be possible, but any threat should remain localized. ..Broyles.. 08/04/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0216 AM CDT Mon Aug 04 2025 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTH-CENTRAL U.S.... ...SUMMARY... Isolated thunderstorms associated with severe gusts and hail will be possible across parts of the north-central U.S. on Wednesday. ...Central and Northern Plains/Upper Mississippi Valley... A large-scale anticyclonic flow pattern is forecast across the central and northern U.S. on Wednesday. At the surface, a moist airmass should be located from the Great Plains into the Mississippi Valley. As surface temperatures warm on Wednesday, moderate instability is expected to develop across much of the moist airmass. Due to the anticyclonic flow pattern and lack of any shortwave trough, large-scale ascent is forecast to remain weak over much of the north-central U.S. In spite of this, isolated thunderstorms may develop in areas that heat up that most, or along pre-existing boundaries. For cells that initiate and persist, deep-layer shear may be strong enough for an isolated severe threat. A few severe gusts and hail will be possible, but any threat should remain localized. ..Broyles.. 08/04/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0216 AM CDT Mon Aug 04 2025 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTH-CENTRAL U.S.... ...SUMMARY... Isolated thunderstorms associated with severe gusts and hail will be possible across parts of the north-central U.S. on Wednesday. ...Central and Northern Plains/Upper Mississippi Valley... A large-scale anticyclonic flow pattern is forecast across the central and northern U.S. on Wednesday. At the surface, a moist airmass should be located from the Great Plains into the Mississippi Valley. As surface temperatures warm on Wednesday, moderate instability is expected to develop across much of the moist airmass. Due to the anticyclonic flow pattern and lack of any shortwave trough, large-scale ascent is forecast to remain weak over much of the north-central U.S. In spite of this, isolated thunderstorms may develop in areas that heat up that most, or along pre-existing boundaries. For cells that initiate and persist, deep-layer shear may be strong enough for an isolated severe threat. A few severe gusts and hail will be possible, but any threat should remain localized. ..Broyles.. 08/04/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0216 AM CDT Mon Aug 04 2025 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTH-CENTRAL U.S.... ...SUMMARY... Isolated thunderstorms associated with severe gusts and hail will be possible across parts of the north-central U.S. on Wednesday. ...Central and Northern Plains/Upper Mississippi Valley... A large-scale anticyclonic flow pattern is forecast across the central and northern U.S. on Wednesday. At the surface, a moist airmass should be located from the Great Plains into the Mississippi Valley. As surface temperatures warm on Wednesday, moderate instability is expected to develop across much of the moist airmass. Due to the anticyclonic flow pattern and lack of any shortwave trough, large-scale ascent is forecast to remain weak over much of the north-central U.S. In spite of this, isolated thunderstorms may develop in areas that heat up that most, or along pre-existing boundaries. For cells that initiate and persist, deep-layer shear may be strong enough for an isolated severe threat. A few severe gusts and hail will be possible, but any threat should remain localized. ..Broyles.. 08/04/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Mon Aug 04 2025 Valid 051200Z - 061200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN/CENTRAL UTAH AND FAR NORTHERN ARIZONA... ...Synopsis... Broad midlevel troughing will persist across the Northwest/Intermountain West, while an expansive midlevel anticyclone builds over the Southwest and southern/central Rockies. ...Great Basin into the central/northern Rockies... Between the expansive midlevel anticyclone and broad midlevel troughing, a belt of enhanced deep-layer west-southwesterly flow will persist across the Great Basin into the northern/central Rockies. Diurnal heating amid a dry antecedent air mass will yield a deeply mixed boundary layer (single-digit to lower teens RH). These dry conditions combined with 15-20 mph sustained west-southwesterly surface winds will lead to widespread elevated fire-weather conditions, with critical conditions expected over southern/central UT into northern AZ (where the overlap of strong winds and low RH atop receptive fuels will be maximized). ..Weinman.. 08/04/2025 ...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 0156 AM CDT Mon Aug 04 2025 Valid 051200Z - 061200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN/CENTRAL UTAH AND FAR NORTHERN ARIZONA... ...Synopsis... Broad midlevel troughing will persist across the Northwest/Intermountain West, while an expansive midlevel anticyclone builds over the Southwest and southern/central Rockies. ...Great Basin into the central/northern Rockies... Between the expansive midlevel anticyclone and broad midlevel troughing, a belt of enhanced deep-layer west-southwesterly flow will persist across the Great Basin into the northern/central Rockies. Diurnal heating amid a dry antecedent air mass will yield a deeply mixed boundary layer (single-digit to lower teens RH). These dry conditions combined with 15-20 mph sustained west-southwesterly surface winds will lead to widespread elevated fire-weather conditions, with critical conditions expected over southern/central UT into northern AZ (where the overlap of strong winds and low RH atop receptive fuels will be maximized). ..Weinman.. 08/04/2025 ...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 0156 AM CDT Mon Aug 04 2025 Valid 051200Z - 061200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN/CENTRAL UTAH AND FAR NORTHERN ARIZONA... ...Synopsis... Broad midlevel troughing will persist across the Northwest/Intermountain West, while an expansive midlevel anticyclone builds over the Southwest and southern/central Rockies. ...Great Basin into the central/northern Rockies... Between the expansive midlevel anticyclone and broad midlevel troughing, a belt of enhanced deep-layer west-southwesterly flow will persist across the Great Basin into the northern/central Rockies. Diurnal heating amid a dry antecedent air mass will yield a deeply mixed boundary layer (single-digit to lower teens RH). These dry conditions combined with 15-20 mph sustained west-southwesterly surface winds will lead to widespread elevated fire-weather conditions, with critical conditions expected over southern/central UT into northern AZ (where the overlap of strong winds and low RH atop receptive fuels will be maximized). ..Weinman.. 08/04/2025 ...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 0156 AM CDT Mon Aug 04 2025 Valid 051200Z - 061200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN/CENTRAL UTAH AND FAR NORTHERN ARIZONA... ...Synopsis... Broad midlevel troughing will persist across the Northwest/Intermountain West, while an expansive midlevel anticyclone builds over the Southwest and southern/central Rockies. ...Great Basin into the central/northern Rockies... Between the expansive midlevel anticyclone and broad midlevel troughing, a belt of enhanced deep-layer west-southwesterly flow will persist across the Great Basin into the northern/central Rockies. Diurnal heating amid a dry antecedent air mass will yield a deeply mixed boundary layer (single-digit to lower teens RH). These dry conditions combined with 15-20 mph sustained west-southwesterly surface winds will lead to widespread elevated fire-weather conditions, with critical conditions expected over southern/central UT into northern AZ (where the overlap of strong winds and low RH atop receptive fuels will be maximized). ..Weinman.. 08/04/2025 ...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 0156 AM CDT Mon Aug 04 2025 Valid 041200Z - 051200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE GREAT BASIN INTO THE CENTRAL ROCKIES... ...Synopsis... Along the northwestern periphery of a large-scale ridge extending from the Southwest into the northern Plains, a compact/robust midlevel trough will advance east-northeastward from the Northwest into the northern Rockies during the day. ...Great Basin into the central Rockies... Between the large-scale ridge and midlevel trough, a belt of moderate deep-layer west-southwesterly flow will overspread the Great Basin into the central Rockies through the afternoon. Here, deep boundary-layer mixing into the enhanced flow aloft will favor widespread single-digit RH and 15-25 mph sustained west-southwesterly surface winds. These dry/windy conditions will lead to critical fire-weather conditions across much of UT and adjacent states, given very receptive fuels. ...Dry Thunderstorms - Intermountain West/Northern Rockies... Strong/focused forcing for ascent accompanying the midlevel trough will aid in thunderstorm development across much of the Intermountain West and northern Rockies throughout the day. Along the southern periphery of deeper midlevel moisture across parts of the Northwest into the northern Rockies, isolated high-based thunderstorms are expected in an air mass characterized by 0.60-0.75 inch PW and inverted-V soundings. This will promote mostly dry thunderstorms with a risk of lightning-induced ignitions and strong-severe outflow winds. Reference the SPC Day 1 Convective Outlook for information on the severe risk. ..Weinman.. 08/04/2025 ...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 0156 AM CDT Mon Aug 04 2025 Valid 041200Z - 051200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE GREAT BASIN INTO THE CENTRAL ROCKIES... ...Synopsis... Along the northwestern periphery of a large-scale ridge extending from the Southwest into the northern Plains, a compact/robust midlevel trough will advance east-northeastward from the Northwest into the northern Rockies during the day. ...Great Basin into the central Rockies... Between the large-scale ridge and midlevel trough, a belt of moderate deep-layer west-southwesterly flow will overspread the Great Basin into the central Rockies through the afternoon. Here, deep boundary-layer mixing into the enhanced flow aloft will favor widespread single-digit RH and 15-25 mph sustained west-southwesterly surface winds. These dry/windy conditions will lead to critical fire-weather conditions across much of UT and adjacent states, given very receptive fuels. ...Dry Thunderstorms - Intermountain West/Northern Rockies... Strong/focused forcing for ascent accompanying the midlevel trough will aid in thunderstorm development across much of the Intermountain West and northern Rockies throughout the day. Along the southern periphery of deeper midlevel moisture across parts of the Northwest into the northern Rockies, isolated high-based thunderstorms are expected in an air mass characterized by 0.60-0.75 inch PW and inverted-V soundings. This will promote mostly dry thunderstorms with a risk of lightning-induced ignitions and strong-severe outflow winds. Reference the SPC Day 1 Convective Outlook for information on the severe risk. ..Weinman.. 08/04/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more