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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CDT Sun Sep 21 2025 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTH TEXAS TO THE TENNESSEE VALLEY... ...SUMMARY... Strong to isolated severe storms are possible from the southern Plains to the Tennessee Valley. ...Discussion... A MCS will likely be ongoing somewhere across eastern Oklahoma on Tuesday morning. A moist airmass with upper 60s to low 70s dewpoints will be in place downstream of these thunderstorms. Only modest weakening of the low-level jet will occur Tuesday morning and therefore, this MCS should remain through much of the day. If sufficient destabilization can occur across Arkansas, northern Mississippi and western TN/KY, some marginal damaging wind threat could accompany this MCS as it moves east through the morning and into the afternoon. Farther west, moderate destabilization is expected across the ArkLaTex and north Texas. A cold front will strengthen/sharpen across Oklahoma and move southeast through the day. Convergence along the front, combined with weak ascent amid falling mid-level heights, will support storm development Tuesday afternoon/evening. Where stronger mid-level flow (40 to 45 knots) is present, shear will support supercells. However, it is unclear whether this stronger mid-level flow will overlap the most favorable zone for storms. Timing and amplitude of the mid-level trough remain uncertain at this time. If this stronger flow overspreads the most favorable thermodynamic zone where storms are anticipated, a Slight Risk may be justified in the ArkLaTex, but model spread remains too large at this time. ..Bentley.. 09/21/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CDT Sun Sep 21 2025 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTH TEXAS TO THE TENNESSEE VALLEY... ...SUMMARY... Strong to isolated severe storms are possible from the southern Plains to the Tennessee Valley. ...Discussion... A MCS will likely be ongoing somewhere across eastern Oklahoma on Tuesday morning. A moist airmass with upper 60s to low 70s dewpoints will be in place downstream of these thunderstorms. Only modest weakening of the low-level jet will occur Tuesday morning and therefore, this MCS should remain through much of the day. If sufficient destabilization can occur across Arkansas, northern Mississippi and western TN/KY, some marginal damaging wind threat could accompany this MCS as it moves east through the morning and into the afternoon. Farther west, moderate destabilization is expected across the ArkLaTex and north Texas. A cold front will strengthen/sharpen across Oklahoma and move southeast through the day. Convergence along the front, combined with weak ascent amid falling mid-level heights, will support storm development Tuesday afternoon/evening. Where stronger mid-level flow (40 to 45 knots) is present, shear will support supercells. However, it is unclear whether this stronger mid-level flow will overlap the most favorable zone for storms. Timing and amplitude of the mid-level trough remain uncertain at this time. If this stronger flow overspreads the most favorable thermodynamic zone where storms are anticipated, a Slight Risk may be justified in the ArkLaTex, but model spread remains too large at this time. ..Bentley.. 09/21/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0203 AM CDT Sun Sep 21 2025 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTH TEXAS TO THE TENNESSEE VALLEY... ...SUMMARY... Strong to isolated severe storms are possible from the southern Plains to the Tennessee Valley. ...Discussion... A MCS will likely be ongoing somewhere across eastern Oklahoma on Tuesday morning. A moist airmass with upper 60s to low 70s dewpoints will be in place downstream of these thunderstorms. Only modest weakening of the low-level jet will occur Tuesday morning and therefore, this MCS should remain through much of the day. If sufficient destabilization can occur across Arkansas, northern Mississippi and western TN/KY, some marginal damaging wind threat could accompany this MCS as it moves east through the morning and into the afternoon. Farther west, moderate destabilization is expected across the ArkLaTex and north Texas. A cold front will strengthen/sharpen across Oklahoma and move southeast through the day. Convergence along the front, combined with weak ascent amid falling mid-level heights, will support storm development Tuesday afternoon/evening. Where stronger mid-level flow (40 to 45 knots) is present, shear will support supercells. However, it is unclear whether this stronger mid-level flow will overlap the most favorable zone for storms. Timing and amplitude of the mid-level trough remain uncertain at this time. If this stronger flow overspreads the most favorable thermodynamic zone where storms are anticipated, a Slight Risk may be justified in the ArkLaTex, but model spread remains too large at this time. ..Bentley.. 09/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0116 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... CORRECTED FOR INCORRECT HAIL GRAPHIC ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0116 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... CORRECTED FOR INCORRECT HAIL GRAPHIC ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0116 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... CORRECTED FOR INCORRECT HAIL GRAPHIC ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0116 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... CORRECTED FOR INCORRECT HAIL GRAPHIC ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0116 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... CORRECTED FOR INCORRECT HAIL GRAPHIC ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... On Monday, a mid-level trough will move from the upper Midwest/Missouri Valley to the Great Lakes/Ohio Valley during the period. Farther west, a more complicated pattern will develop as a ridge builds into the Pacific Northwest. As this ridge builds, a mid-level jet streak will be shunted south across the central Rockies. This will deepen a mid-level low with a closed circulation likely developing across the central High Plains region by 12Z Tuesday. In addition, a closed low will persist off the southern California coast for much of the period. High pressure will be present across much of the western CONUS with weak lee troughing along the central and southern High Plains. The surface pattern will be somewhat less defined farther east with a weak remnant front likely through the Upper Midwest to the western Great Lakes. High pressure will dominate areas east of the Appalachians. ...Central Plains... Moderate to strong instability will develop by Monday afternoon in the wake of a morning MCS across Oklahoma/Kansas. Forecast soundings show a strongly capped airmass across Kansas/Oklahoma and given the relatively weak forcing amid modest height falls, do not expect much thunderstorm development until after 00Z. After this time, the mid-level trough will start to overspread the Plains with a strengthening low-level jet potentially approaching 50 knots. Cooling temperatures aloft and strong isentropic ascent should result in thunderstorm development after sunset Monday evening. Seep mid-level lapse rates and strengthening effective shear (40 to 50 knots) will support the potential for supercells with some hail threat. As upscale growth continues, the severe wind threat should increase and continue into the overnight period into portions of central/northern Oklahoma. ...NE/IA to Lake Michigan... Diurnal thunderstorm development is possible along a diffuse frontal zone from Nebraska to southern Wisconsin. Modest lapse rates and moderate instability along this zone will support some multicells capable of some hail or damaging wind gusts. However, mostly weak deep-layer shear (20 knots) and weak upper forcing should keep the overall threat along this zone relatively isolated. ...Tennessee Valley to the eastern Great Lakes... A weak mid-level shortwave trough is forecast to move through the Ohio Valley on Monday with moderate instability forecast ahead of it. An uncapped airmass and some moderate upper-level support in a broader zone of weak, but persistent isentropic ascent should support scattered thunderstorm development. Lapse rates will be poor, but modest effective shear amid 30 to 35 knots of mid-level flow may support some organized multicells capable of damaging wind gusts Monday afternoon/evening. ..Bentley.. 09/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...MID MS VALLEY...OH VALLEY...AND SOUTHERN GREAT LAKES...AND ALSO FROM NORTHEAST NE/SOUTHEAST SD INTO SOUTHERN MN/NORTHERN IA... ...SUMMARY... Isolated severe thunderstorms are possible later today across parts of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and southern Great Lakes. A few strong to severe thunderstorms are also possible from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Synopsis... A broad mid/upper-level trough will cover much of the central/eastern CONUS later today, with several embedded vorticity maxima expected to move across parts of the Great Plains into the Midwest and Ohio Valley. Modest midlevel flow atop a sufficiently moist and unstable environment will support some potential for strong to locally severe storms across a relatively large area. Localized corridors of somewhat greater severe threat may evolve where deep-layer shear is enhanced by one of the embedded midlevel shortwaves, as well as where midlevel flow veers to west-northwesterly across parts of the mid MO Valley and southern Plains. ...Parts of TX into southern OK... Extensive overnight convection is expected to leave a residual outflow boundary that will be located somewhere in the vicinity of north TX/southern OK by afternoon. While some midlevel warming is expected across the southern Plains through the day, relatively strong heating, and the potential influence of an MCV that may evolve from overnight convection, will support isolated to widely scattered storm development this afternoon/evening near the outflow boundary, and potentially southward along a diffuse dryline into northwest/west-central TX. Moderate buoyancy and 35-50 kt of effective shear within the northwesterly flow regime across parts of north TX into southern OK will conditionally support splitting supercells capable of producing hail and localized severe gusts. There is some uncertainty regarding the placement of the boundary by afternoon and the magnitude of any MCV-related enhancement to deep-layer shear and storm coverage, but greater probabilities may be needed if confidence increases in development of multiple supercells and/or an organized cluster within this regime. ...Northeast NE/southeast SD into southern MN/northern IA... A compact mid/upper-level low will move southeastward from eastern ND into MN later today. This low and the attendant shortwave trough will aid in the development of isolated to widely scattered storms by late afternoon or early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Relatively cool temperatures aloft, moderate buoyancy, and effective shear of 25-35 kt will support strong multicells and perhaps a couple splitting supercells. Large hail is expected to the primary hazard, though localized strong gusts will also be possible with the strongest storms. ...Eastern KS into MO... A cluster of elevated convection will likely be ongoing at the start of the period across central/eastern KS. This cluster and possibly an attendant MCV may encounter an environment across parts of MO that is recovering from a separate area of overnight convection near the Ozarks. While background midlevel flow will only support effective shear of 20-25 kt, any MCV-related enhancement to the flow would result in sufficient deep-layer shear for somewhat more organized storms. If sufficient destabilization can occur, then a few modestly organized cells or clusters may evolve this afternoon and evening, accompanied by a threat for localized damaging wind and perhaps some hail. ...Parts of the Ohio Valley and Great Lakes... Modest deep-layer southwesterly flow will overspread parts of the southern Great Lakes and Ohio Valley later today, in advance of the midlevel shortwave trough moving across the upper MS Valley. Scattered thunderstorm development is expected across the region, within a moderately unstable and weakly capped environment. Midlevel lapse rates and deep-layer shear are expected to remain relatively weak, but steepening low-level lapse rates will result in potential for cells/clusters capable of locally damaging wind this afternoon into the early evening. There is also some potential for a storm cluster or loosely organized MCS to develop across the lower MO/mid MS Valley and move toward parts of the southern Great Lakes later tonight. ..Dean/Halbert.. 09/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...MID MS VALLEY...OH VALLEY...AND SOUTHERN GREAT LAKES...AND ALSO FROM NORTHEAST NE/SOUTHEAST SD INTO SOUTHERN MN/NORTHERN IA... ...SUMMARY... Isolated severe thunderstorms are possible later today across parts of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and southern Great Lakes. A few strong to severe thunderstorms are also possible from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Synopsis... A broad mid/upper-level trough will cover much of the central/eastern CONUS later today, with several embedded vorticity maxima expected to move across parts of the Great Plains into the Midwest and Ohio Valley. Modest midlevel flow atop a sufficiently moist and unstable environment will support some potential for strong to locally severe storms across a relatively large area. Localized corridors of somewhat greater severe threat may evolve where deep-layer shear is enhanced by one of the embedded midlevel shortwaves, as well as where midlevel flow veers to west-northwesterly across parts of the mid MO Valley and southern Plains. ...Parts of TX into southern OK... Extensive overnight convection is expected to leave a residual outflow boundary that will be located somewhere in the vicinity of north TX/southern OK by afternoon. While some midlevel warming is expected across the southern Plains through the day, relatively strong heating, and the potential influence of an MCV that may evolve from overnight convection, will support isolated to widely scattered storm development this afternoon/evening near the outflow boundary, and potentially southward along a diffuse dryline into northwest/west-central TX. Moderate buoyancy and 35-50 kt of effective shear within the northwesterly flow regime across parts of north TX into southern OK will conditionally support splitting supercells capable of producing hail and localized severe gusts. There is some uncertainty regarding the placement of the boundary by afternoon and the magnitude of any MCV-related enhancement to deep-layer shear and storm coverage, but greater probabilities may be needed if confidence increases in development of multiple supercells and/or an organized cluster within this regime. ...Northeast NE/southeast SD into southern MN/northern IA... A compact mid/upper-level low will move southeastward from eastern ND into MN later today. This low and the attendant shortwave trough will aid in the development of isolated to widely scattered storms by late afternoon or early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Relatively cool temperatures aloft, moderate buoyancy, and effective shear of 25-35 kt will support strong multicells and perhaps a couple splitting supercells. Large hail is expected to the primary hazard, though localized strong gusts will also be possible with the strongest storms. ...Eastern KS into MO... A cluster of elevated convection will likely be ongoing at the start of the period across central/eastern KS. This cluster and possibly an attendant MCV may encounter an environment across parts of MO that is recovering from a separate area of overnight convection near the Ozarks. While background midlevel flow will only support effective shear of 20-25 kt, any MCV-related enhancement to the flow would result in sufficient deep-layer shear for somewhat more organized storms. If sufficient destabilization can occur, then a few modestly organized cells or clusters may evolve this afternoon and evening, accompanied by a threat for localized damaging wind and perhaps some hail. ...Parts of the Ohio Valley and Great Lakes... Modest deep-layer southwesterly flow will overspread parts of the southern Great Lakes and Ohio Valley later today, in advance of the midlevel shortwave trough moving across the upper MS Valley. Scattered thunderstorm development is expected across the region, within a moderately unstable and weakly capped environment. Midlevel lapse rates and deep-layer shear are expected to remain relatively weak, but steepening low-level lapse rates will result in potential for cells/clusters capable of locally damaging wind this afternoon into the early evening. There is also some potential for a storm cluster or loosely organized MCS to develop across the lower MO/mid MS Valley and move toward parts of the southern Great Lakes later tonight. ..Dean/Halbert.. 09/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...MID MS VALLEY...OH VALLEY...AND SOUTHERN GREAT LAKES...AND ALSO FROM NORTHEAST NE/SOUTHEAST SD INTO SOUTHERN MN/NORTHERN IA... ...SUMMARY... Isolated severe thunderstorms are possible later today across parts of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and southern Great Lakes. A few strong to severe thunderstorms are also possible from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Synopsis... A broad mid/upper-level trough will cover much of the central/eastern CONUS later today, with several embedded vorticity maxima expected to move across parts of the Great Plains into the Midwest and Ohio Valley. Modest midlevel flow atop a sufficiently moist and unstable environment will support some potential for strong to locally severe storms across a relatively large area. Localized corridors of somewhat greater severe threat may evolve where deep-layer shear is enhanced by one of the embedded midlevel shortwaves, as well as where midlevel flow veers to west-northwesterly across parts of the mid MO Valley and southern Plains. ...Parts of TX into southern OK... Extensive overnight convection is expected to leave a residual outflow boundary that will be located somewhere in the vicinity of north TX/southern OK by afternoon. While some midlevel warming is expected across the southern Plains through the day, relatively strong heating, and the potential influence of an MCV that may evolve from overnight convection, will support isolated to widely scattered storm development this afternoon/evening near the outflow boundary, and potentially southward along a diffuse dryline into northwest/west-central TX. Moderate buoyancy and 35-50 kt of effective shear within the northwesterly flow regime across parts of north TX into southern OK will conditionally support splitting supercells capable of producing hail and localized severe gusts. There is some uncertainty regarding the placement of the boundary by afternoon and the magnitude of any MCV-related enhancement to deep-layer shear and storm coverage, but greater probabilities may be needed if confidence increases in development of multiple supercells and/or an organized cluster within this regime. ...Northeast NE/southeast SD into southern MN/northern IA... A compact mid/upper-level low will move southeastward from eastern ND into MN later today. This low and the attendant shortwave trough will aid in the development of isolated to widely scattered storms by late afternoon or early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Relatively cool temperatures aloft, moderate buoyancy, and effective shear of 25-35 kt will support strong multicells and perhaps a couple splitting supercells. Large hail is expected to the primary hazard, though localized strong gusts will also be possible with the strongest storms. ...Eastern KS into MO... A cluster of elevated convection will likely be ongoing at the start of the period across central/eastern KS. This cluster and possibly an attendant MCV may encounter an environment across parts of MO that is recovering from a separate area of overnight convection near the Ozarks. While background midlevel flow will only support effective shear of 20-25 kt, any MCV-related enhancement to the flow would result in sufficient deep-layer shear for somewhat more organized storms. If sufficient destabilization can occur, then a few modestly organized cells or clusters may evolve this afternoon and evening, accompanied by a threat for localized damaging wind and perhaps some hail. ...Parts of the Ohio Valley and Great Lakes... Modest deep-layer southwesterly flow will overspread parts of the southern Great Lakes and Ohio Valley later today, in advance of the midlevel shortwave trough moving across the upper MS Valley. Scattered thunderstorm development is expected across the region, within a moderately unstable and weakly capped environment. Midlevel lapse rates and deep-layer shear are expected to remain relatively weak, but steepening low-level lapse rates will result in potential for cells/clusters capable of locally damaging wind this afternoon into the early evening. There is also some potential for a storm cluster or loosely organized MCS to develop across the lower MO/mid MS Valley and move toward parts of the southern Great Lakes later tonight. ..Dean/Halbert.. 09/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...MID MS VALLEY...OH VALLEY...AND SOUTHERN GREAT LAKES...AND ALSO FROM NORTHEAST NE/SOUTHEAST SD INTO SOUTHERN MN/NORTHERN IA... ...SUMMARY... Isolated severe thunderstorms are possible later today across parts of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and southern Great Lakes. A few strong to severe thunderstorms are also possible from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Synopsis... A broad mid/upper-level trough will cover much of the central/eastern CONUS later today, with several embedded vorticity maxima expected to move across parts of the Great Plains into the Midwest and Ohio Valley. Modest midlevel flow atop a sufficiently moist and unstable environment will support some potential for strong to locally severe storms across a relatively large area. Localized corridors of somewhat greater severe threat may evolve where deep-layer shear is enhanced by one of the embedded midlevel shortwaves, as well as where midlevel flow veers to west-northwesterly across parts of the mid MO Valley and southern Plains. ...Parts of TX into southern OK... Extensive overnight convection is expected to leave a residual outflow boundary that will be located somewhere in the vicinity of north TX/southern OK by afternoon. While some midlevel warming is expected across the southern Plains through the day, relatively strong heating, and the potential influence of an MCV that may evolve from overnight convection, will support isolated to widely scattered storm development this afternoon/evening near the outflow boundary, and potentially southward along a diffuse dryline into northwest/west-central TX. Moderate buoyancy and 35-50 kt of effective shear within the northwesterly flow regime across parts of north TX into southern OK will conditionally support splitting supercells capable of producing hail and localized severe gusts. There is some uncertainty regarding the placement of the boundary by afternoon and the magnitude of any MCV-related enhancement to deep-layer shear and storm coverage, but greater probabilities may be needed if confidence increases in development of multiple supercells and/or an organized cluster within this regime. ...Northeast NE/southeast SD into southern MN/northern IA... A compact mid/upper-level low will move southeastward from eastern ND into MN later today. This low and the attendant shortwave trough will aid in the development of isolated to widely scattered storms by late afternoon or early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Relatively cool temperatures aloft, moderate buoyancy, and effective shear of 25-35 kt will support strong multicells and perhaps a couple splitting supercells. Large hail is expected to the primary hazard, though localized strong gusts will also be possible with the strongest storms. ...Eastern KS into MO... A cluster of elevated convection will likely be ongoing at the start of the period across central/eastern KS. This cluster and possibly an attendant MCV may encounter an environment across parts of MO that is recovering from a separate area of overnight convection near the Ozarks. While background midlevel flow will only support effective shear of 20-25 kt, any MCV-related enhancement to the flow would result in sufficient deep-layer shear for somewhat more organized storms. If sufficient destabilization can occur, then a few modestly organized cells or clusters may evolve this afternoon and evening, accompanied by a threat for localized damaging wind and perhaps some hail. ...Parts of the Ohio Valley and Great Lakes... Modest deep-layer southwesterly flow will overspread parts of the southern Great Lakes and Ohio Valley later today, in advance of the midlevel shortwave trough moving across the upper MS Valley. Scattered thunderstorm development is expected across the region, within a moderately unstable and weakly capped environment. Midlevel lapse rates and deep-layer shear are expected to remain relatively weak, but steepening low-level lapse rates will result in potential for cells/clusters capable of locally damaging wind this afternoon into the early evening. There is also some potential for a storm cluster or loosely organized MCS to develop across the lower MO/mid MS Valley and move toward parts of the southern Great Lakes later tonight. ..Dean/Halbert.. 09/21/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE OZARKS...MID MS VALLEY...OH VALLEY...AND SOUTHERN GREAT LAKES...AND ALSO FROM NORTHEAST NE/SOUTHEAST SD INTO SOUTHERN MN/NORTHERN IA... ...SUMMARY... Isolated severe thunderstorms are possible later today across parts of the southern Plains into the Ozarks, mid Mississippi Valley, Ohio Valley, and southern Great Lakes. A few strong to severe thunderstorms are also possible from the mid Missouri Valley into southern Minnesota and northern Iowa. ...Synopsis... A broad mid/upper-level trough will cover much of the central/eastern CONUS later today, with several embedded vorticity maxima expected to move across parts of the Great Plains into the Midwest and Ohio Valley. Modest midlevel flow atop a sufficiently moist and unstable environment will support some potential for strong to locally severe storms across a relatively large area. Localized corridors of somewhat greater severe threat may evolve where deep-layer shear is enhanced by one of the embedded midlevel shortwaves, as well as where midlevel flow veers to west-northwesterly across parts of the mid MO Valley and southern Plains. ...Parts of TX into southern OK... Extensive overnight convection is expected to leave a residual outflow boundary that will be located somewhere in the vicinity of north TX/southern OK by afternoon. While some midlevel warming is expected across the southern Plains through the day, relatively strong heating, and the potential influence of an MCV that may evolve from overnight convection, will support isolated to widely scattered storm development this afternoon/evening near the outflow boundary, and potentially southward along a diffuse dryline into northwest/west-central TX. Moderate buoyancy and 35-50 kt of effective shear within the northwesterly flow regime across parts of north TX into southern OK will conditionally support splitting supercells capable of producing hail and localized severe gusts. There is some uncertainty regarding the placement of the boundary by afternoon and the magnitude of any MCV-related enhancement to deep-layer shear and storm coverage, but greater probabilities may be needed if confidence increases in development of multiple supercells and/or an organized cluster within this regime. ...Northeast NE/southeast SD into southern MN/northern IA... A compact mid/upper-level low will move southeastward from eastern ND into MN later today. This low and the attendant shortwave trough will aid in the development of isolated to widely scattered storms by late afternoon or early evening from southwest MN into adjacent southeast SD, northeast NE, and northwest IA, in the vicinity of a weak surface boundary. Relatively cool temperatures aloft, moderate buoyancy, and effective shear of 25-35 kt will support strong multicells and perhaps a couple splitting supercells. Large hail is expected to the primary hazard, though localized strong gusts will also be possible with the strongest storms. ...Eastern KS into MO... A cluster of elevated convection will likely be ongoing at the start of the period across central/eastern KS. This cluster and possibly an attendant MCV may encounter an environment across parts of MO that is recovering from a separate area of overnight convection near the Ozarks. While background midlevel flow will only support effective shear of 20-25 kt, any MCV-related enhancement to the flow would result in sufficient deep-layer shear for somewhat more organized storms. If sufficient destabilization can occur, then a few modestly organized cells or clusters may evolve this afternoon and evening, accompanied by a threat for localized damaging wind and perhaps some hail. ...Parts of the Ohio Valley and Great Lakes... Modest deep-layer southwesterly flow will overspread parts of the southern Great Lakes and Ohio Valley later today, in advance of the midlevel shortwave trough moving across the upper MS Valley. Scattered thunderstorm development is expected across the region, within a moderately unstable and weakly capped environment. Midlevel lapse rates and deep-layer shear are expected to remain relatively weak, but steepening low-level lapse rates will result in potential for cells/clusters capable of locally damaging wind this afternoon into the early evening. There is also some potential for a storm cluster or loosely organized MCS to develop across the lower MO/mid MS Valley and move toward parts of the southern Great Lakes later tonight. ..Dean/Halbert.. 09/21/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive mid-level trough is forecast to traverse the northern Rockies on Monday, bringing a cold front to the northern and central Great Plains. However, there is no appreciable overlap between receptive fuels, strong surface winds, low relative humidity, or the occurrence of dry thunderstorms across the continental U.S. to support fire-weather highlights at this time. ..Halbert.. 09/21/2025 ...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 1247 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive mid-level trough is forecast to traverse the northern Rockies on Monday, bringing a cold front to the northern and central Great Plains. However, there is no appreciable overlap between receptive fuels, strong surface winds, low relative humidity, or the occurrence of dry thunderstorms across the continental U.S. to support fire-weather highlights at this time. ..Halbert.. 09/21/2025 ...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 1247 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive mid-level trough is forecast to traverse the northern Rockies on Monday, bringing a cold front to the northern and central Great Plains. However, there is no appreciable overlap between receptive fuels, strong surface winds, low relative humidity, or the occurrence of dry thunderstorms across the continental U.S. to support fire-weather highlights at this time. ..Halbert.. 09/21/2025 ...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 1247 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive mid-level trough is forecast to traverse the northern Rockies on Monday, bringing a cold front to the northern and central Great Plains. However, there is no appreciable overlap between receptive fuels, strong surface winds, low relative humidity, or the occurrence of dry thunderstorms across the continental U.S. to support fire-weather highlights at this time. ..Halbert.. 09/21/2025 ...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 1247 AM CDT Sun Sep 21 2025 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A progressive mid-level trough is forecast to traverse the northern Rockies on Monday, bringing a cold front to the northern and central Great Plains. However, there is no appreciable overlap between receptive fuels, strong surface winds, low relative humidity, or the occurrence of dry thunderstorms across the continental U.S. to support fire-weather highlights at this time. ..Halbert.. 09/21/2025 ...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 1246 AM CDT Sun Sep 21 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... Generally weak surface winds across the continental U.S., and higher relative humidity and precipitation across the few localized regions of higher winds, will result in minimal fire-weather concerns today. ...North Cascades into the Columbia Basin... Winds in the Cascade gaps and into the Columbia Basin are still forecast to gust as high as 20 MPH. While these winds could impact existing fires across the area, relative humidity is not forecast to get below 30% in large part due to cloud cover and precipitation. Therefore, fire-weather highlights have been withheld at this time. ..Halbert.. 09/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more