Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Sep 10 2025 Valid 101630Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS/FRONT RANGE AND GREAT BASIN/INTERIOR WEST... ...SUMMARY... A few severe storms could occur this afternoon and early evening across the north-central High Plains and Great Basin. ...High Plains/Front Range... As the upper ridge tends to abate/shift away, the region will begin to be influenced by the upper trough over the West. While some stronger storms could occur across a relatively broad north-south extent of the High Plains, portions of eastern Wyoming and the northern Colorado Front Range and immediately adjacent High Plains are expected to be influenced by somewhat stronger mid-level westerlies (25 kt), aside from steep lapse rates and moderate buoyancy. Low severe probabilities have been introduced for what should be an isolated/relatively marginal severe potential later this afternoon into evening. ...Great Basin/Interior West... The region will be influenced by a belt of stronger cyclonic flow aloft preceding the upper low centered over northern California. Adequate moisture, steep lapse rates, and stronger deep-layer winds could allow for some storms to produce gusty winds and small hail, mainly across central/northern Nevada into southwest Idaho. ..Guyer/Weinman.. 09/10/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Sep 10 2025 Valid 101630Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS/FRONT RANGE AND GREAT BASIN/INTERIOR WEST... ...SUMMARY... A few severe storms could occur this afternoon and early evening across the north-central High Plains and Great Basin. ...High Plains/Front Range... As the upper ridge tends to abate/shift away, the region will begin to be influenced by the upper trough over the West. While some stronger storms could occur across a relatively broad north-south extent of the High Plains, portions of eastern Wyoming and the northern Colorado Front Range and immediately adjacent High Plains are expected to be influenced by somewhat stronger mid-level westerlies (25 kt), aside from steep lapse rates and moderate buoyancy. Low severe probabilities have been introduced for what should be an isolated/relatively marginal severe potential later this afternoon into evening. ...Great Basin/Interior West... The region will be influenced by a belt of stronger cyclonic flow aloft preceding the upper low centered over northern California. Adequate moisture, steep lapse rates, and stronger deep-layer winds could allow for some storms to produce gusty winds and small hail, mainly across central/northern Nevada into southwest Idaho. ..Guyer/Weinman.. 09/10/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Sep 10 2025 Valid 101630Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS/FRONT RANGE AND GREAT BASIN/INTERIOR WEST... ...SUMMARY... A few severe storms could occur this afternoon and early evening across the north-central High Plains and Great Basin. ...High Plains/Front Range... As the upper ridge tends to abate/shift away, the region will begin to be influenced by the upper trough over the West. While some stronger storms could occur across a relatively broad north-south extent of the High Plains, portions of eastern Wyoming and the northern Colorado Front Range and immediately adjacent High Plains are expected to be influenced by somewhat stronger mid-level westerlies (25 kt), aside from steep lapse rates and moderate buoyancy. Low severe probabilities have been introduced for what should be an isolated/relatively marginal severe potential later this afternoon into evening. ...Great Basin/Interior West... The region will be influenced by a belt of stronger cyclonic flow aloft preceding the upper low centered over northern California. Adequate moisture, steep lapse rates, and stronger deep-layer winds could allow for some storms to produce gusty winds and small hail, mainly across central/northern Nevada into southwest Idaho. ..Guyer/Weinman.. 09/10/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Sep 10 2025 Valid 101630Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS/FRONT RANGE AND GREAT BASIN/INTERIOR WEST... ...SUMMARY... A few severe storms could occur this afternoon and early evening across the north-central High Plains and Great Basin. ...High Plains/Front Range... As the upper ridge tends to abate/shift away, the region will begin to be influenced by the upper trough over the West. While some stronger storms could occur across a relatively broad north-south extent of the High Plains, portions of eastern Wyoming and the northern Colorado Front Range and immediately adjacent High Plains are expected to be influenced by somewhat stronger mid-level westerlies (25 kt), aside from steep lapse rates and moderate buoyancy. Low severe probabilities have been introduced for what should be an isolated/relatively marginal severe potential later this afternoon into evening. ...Great Basin/Interior West... The region will be influenced by a belt of stronger cyclonic flow aloft preceding the upper low centered over northern California. Adequate moisture, steep lapse rates, and stronger deep-layer winds could allow for some storms to produce gusty winds and small hail, mainly across central/northern Nevada into southwest Idaho. ..Guyer/Weinman.. 09/10/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Wed Sep 10 2025 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered showers and thunderstorms are possible over parts of the Northwest and northern Rockies with more isolated storms over the High Plains. Severe potential is generally low. ...Synopsis... Water-vapor imagery this morning shows an upper low situated over northern CA, and it will remain nearly stationary during the period with a large area of cyclonic flow extending from southern CA into the eastern Great Basin and central Rockies. A downstream upper ridge over the High Plains will feature a lee trough that will act to focus isolated to scattered thunderstorms from MT southward into the central High Plains. Strong heating and weak upslope flow beneath the aforementioned upper-level ridge will favor a few isolated cells developing during peak heating. A couple of the more vigorous storms may be capable of localized strong gusts near 1) NM/OK/TX/CO border, 2) east of the CO Front Range in the High Plains, and 3) in eastern WY. Warming aloft is expected to mitigate the overall potential with these storms. Farther west, a mid-level shortwave trough will move through the base of the West Coast mid- to upper low/trough and to near the UT/NV border by late afternoon/early evening. A corresponding belt of 50-kt southwesterly 500-mb flow will overspread western UT. Isolated dry microbursts may accompany the stronger storms over central UT into western CO during the 22-02z period. Elsewhere, scattered afternoon storms will occur beneath the upper trough from northern NV into OR and western ID, and a few of these storms could produce at least small hail given such cool temperatures aloft and modest deep-layer shear. ..Smith/Broyles.. 09/10/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Wed Sep 10 2025 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered showers and thunderstorms are possible over parts of the Northwest and northern Rockies with more isolated storms over the High Plains. Severe potential is generally low. ...Synopsis... Water-vapor imagery this morning shows an upper low situated over northern CA, and it will remain nearly stationary during the period with a large area of cyclonic flow extending from southern CA into the eastern Great Basin and central Rockies. A downstream upper ridge over the High Plains will feature a lee trough that will act to focus isolated to scattered thunderstorms from MT southward into the central High Plains. Strong heating and weak upslope flow beneath the aforementioned upper-level ridge will favor a few isolated cells developing during peak heating. A couple of the more vigorous storms may be capable of localized strong gusts near 1) NM/OK/TX/CO border, 2) east of the CO Front Range in the High Plains, and 3) in eastern WY. Warming aloft is expected to mitigate the overall potential with these storms. Farther west, a mid-level shortwave trough will move through the base of the West Coast mid- to upper low/trough and to near the UT/NV border by late afternoon/early evening. A corresponding belt of 50-kt southwesterly 500-mb flow will overspread western UT. Isolated dry microbursts may accompany the stronger storms over central UT into western CO during the 22-02z period. Elsewhere, scattered afternoon storms will occur beneath the upper trough from northern NV into OR and western ID, and a few of these storms could produce at least small hail given such cool temperatures aloft and modest deep-layer shear. ..Smith/Broyles.. 09/10/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Wed Sep 10 2025 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered showers and thunderstorms are possible over parts of the Northwest and northern Rockies with more isolated storms over the High Plains. Severe potential is generally low. ...Synopsis... Water-vapor imagery this morning shows an upper low situated over northern CA, and it will remain nearly stationary during the period with a large area of cyclonic flow extending from southern CA into the eastern Great Basin and central Rockies. A downstream upper ridge over the High Plains will feature a lee trough that will act to focus isolated to scattered thunderstorms from MT southward into the central High Plains. Strong heating and weak upslope flow beneath the aforementioned upper-level ridge will favor a few isolated cells developing during peak heating. A couple of the more vigorous storms may be capable of localized strong gusts near 1) NM/OK/TX/CO border, 2) east of the CO Front Range in the High Plains, and 3) in eastern WY. Warming aloft is expected to mitigate the overall potential with these storms. Farther west, a mid-level shortwave trough will move through the base of the West Coast mid- to upper low/trough and to near the UT/NV border by late afternoon/early evening. A corresponding belt of 50-kt southwesterly 500-mb flow will overspread western UT. Isolated dry microbursts may accompany the stronger storms over central UT into western CO during the 22-02z period. Elsewhere, scattered afternoon storms will occur beneath the upper trough from northern NV into OR and western ID, and a few of these storms could produce at least small hail given such cool temperatures aloft and modest deep-layer shear. ..Smith/Broyles.. 09/10/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Sep 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Severe potential in the extended forecast period will be tied to a shortwave trough and stronger southwesterly flow aloft emanating from the Rockies over the central US. Flow aloft will increase D4/Saturday as the upper trough begins to overspread the central US. Ascent from the trough will maintain a weak surface low and stationary front over the northern Plains and Upper Midwest. At the same time, a weak cold front will move eastward over the High Plains serving as a focus for thunderstorm development from the Dakotas and MN to the southern Plains each afternoon. Some isolated severe potential is apparent near the surface low/stalled front over the northern Plains and along the cold front farther south through the remainder of the weekend. However, model guidance varies widely on available moisture/buoyancy and the overlap with more robust vertical shear. This continues to cast significant uncertainty on severe probabilities through the first half of the extended forecast period. By early next week, mid-level ridging is expected to strengthen, forcing stronger flow aloft northward as the primary western trough begins to weaken. A second trough will stall over the West as the ridge continues to build. This should favor drier surface conditions while also limiting the overlap of buoyancy with stronger flow aloft. Severe potential appears limited beyond this weekend and into the first half of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Sep 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Severe potential in the extended forecast period will be tied to a shortwave trough and stronger southwesterly flow aloft emanating from the Rockies over the central US. Flow aloft will increase D4/Saturday as the upper trough begins to overspread the central US. Ascent from the trough will maintain a weak surface low and stationary front over the northern Plains and Upper Midwest. At the same time, a weak cold front will move eastward over the High Plains serving as a focus for thunderstorm development from the Dakotas and MN to the southern Plains each afternoon. Some isolated severe potential is apparent near the surface low/stalled front over the northern Plains and along the cold front farther south through the remainder of the weekend. However, model guidance varies widely on available moisture/buoyancy and the overlap with more robust vertical shear. This continues to cast significant uncertainty on severe probabilities through the first half of the extended forecast period. By early next week, mid-level ridging is expected to strengthen, forcing stronger flow aloft northward as the primary western trough begins to weaken. A second trough will stall over the West as the ridge continues to build. This should favor drier surface conditions while also limiting the overlap of buoyancy with stronger flow aloft. Severe potential appears limited beyond this weekend and into the first half of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Sep 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Severe potential in the extended forecast period will be tied to a shortwave trough and stronger southwesterly flow aloft emanating from the Rockies over the central US. Flow aloft will increase D4/Saturday as the upper trough begins to overspread the central US. Ascent from the trough will maintain a weak surface low and stationary front over the northern Plains and Upper Midwest. At the same time, a weak cold front will move eastward over the High Plains serving as a focus for thunderstorm development from the Dakotas and MN to the southern Plains each afternoon. Some isolated severe potential is apparent near the surface low/stalled front over the northern Plains and along the cold front farther south through the remainder of the weekend. However, model guidance varies widely on available moisture/buoyancy and the overlap with more robust vertical shear. This continues to cast significant uncertainty on severe probabilities through the first half of the extended forecast period. By early next week, mid-level ridging is expected to strengthen, forcing stronger flow aloft northward as the primary western trough begins to weaken. A second trough will stall over the West as the ridge continues to build. This should favor drier surface conditions while also limiting the overlap of buoyancy with stronger flow aloft. Severe potential appears limited beyond this weekend and into the first half of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Sep 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Severe potential in the extended forecast period will be tied to a shortwave trough and stronger southwesterly flow aloft emanating from the Rockies over the central US. Flow aloft will increase D4/Saturday as the upper trough begins to overspread the central US. Ascent from the trough will maintain a weak surface low and stationary front over the northern Plains and Upper Midwest. At the same time, a weak cold front will move eastward over the High Plains serving as a focus for thunderstorm development from the Dakotas and MN to the southern Plains each afternoon. Some isolated severe potential is apparent near the surface low/stalled front over the northern Plains and along the cold front farther south through the remainder of the weekend. However, model guidance varies widely on available moisture/buoyancy and the overlap with more robust vertical shear. This continues to cast significant uncertainty on severe probabilities through the first half of the extended forecast period. By early next week, mid-level ridging is expected to strengthen, forcing stronger flow aloft northward as the primary western trough begins to weaken. A second trough will stall over the West as the ridge continues to build. This should favor drier surface conditions while also limiting the overlap of buoyancy with stronger flow aloft. Severe potential appears limited beyond this weekend and into the first half of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Sep 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Severe potential in the extended forecast period will be tied to a shortwave trough and stronger southwesterly flow aloft emanating from the Rockies over the central US. Flow aloft will increase D4/Saturday as the upper trough begins to overspread the central US. Ascent from the trough will maintain a weak surface low and stationary front over the northern Plains and Upper Midwest. At the same time, a weak cold front will move eastward over the High Plains serving as a focus for thunderstorm development from the Dakotas and MN to the southern Plains each afternoon. Some isolated severe potential is apparent near the surface low/stalled front over the northern Plains and along the cold front farther south through the remainder of the weekend. However, model guidance varies widely on available moisture/buoyancy and the overlap with more robust vertical shear. This continues to cast significant uncertainty on severe probabilities through the first half of the extended forecast period. By early next week, mid-level ridging is expected to strengthen, forcing stronger flow aloft northward as the primary western trough begins to weaken. A second trough will stall over the West as the ridge continues to build. This should favor drier surface conditions while also limiting the overlap of buoyancy with stronger flow aloft. Severe potential appears limited beyond this weekend and into the first half of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Wed Sep 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Severe potential in the extended forecast period will be tied to a shortwave trough and stronger southwesterly flow aloft emanating from the Rockies over the central US. Flow aloft will increase D4/Saturday as the upper trough begins to overspread the central US. Ascent from the trough will maintain a weak surface low and stationary front over the northern Plains and Upper Midwest. At the same time, a weak cold front will move eastward over the High Plains serving as a focus for thunderstorm development from the Dakotas and MN to the southern Plains each afternoon. Some isolated severe potential is apparent near the surface low/stalled front over the northern Plains and along the cold front farther south through the remainder of the weekend. However, model guidance varies widely on available moisture/buoyancy and the overlap with more robust vertical shear. This continues to cast significant uncertainty on severe probabilities through the first half of the extended forecast period. By early next week, mid-level ridging is expected to strengthen, forcing stronger flow aloft northward as the primary western trough begins to weaken. A second trough will stall over the West as the ridge continues to build. This should favor drier surface conditions while also limiting the overlap of buoyancy with stronger flow aloft. Severe potential appears limited beyond this weekend and into the first half of next week. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Wed Sep 10 2025 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated storms are possible over parts of the Northern Plains and Upper Midwest with additional storms possible over the Rockies and Great Basin Friday. Severe potential is uncertain. ...Northern Plains and Upper Midwest... Shortwave ridging over the northern Plains and Upper Midwest is forecast to shift eastward Friday as weak troughing emerges from the Rockies. A modest increase in mid-level southwesterly flow will impinge upon rich low-level moisture near a weakening surface low and stalled warm front across the Dakotas and western MN. Low-level convergence near the low/front may serve as a focus for isolated thunderstorm development Friday afternoon and evening. Moderate MLCAPE around 2000 J/kg and steepening mid-level lapse rates could support a few stronger storms. Some enhancement of the mid-level flow may allow for a few storms to organize with some clustering and isolated strong outflow gusts. The primary uncertainty remains storm coverage with most guidance showing only sporadic convection through much of the day. An increase in convective coverage is possible overnight and into early Saturday as a 35-40 kt southerly low-level jet develops across the central Plains, bolstering low-level warm advection. Should this occur, one or more clusters of thunderstorms could propagate eastward along the warm front, potentially posing a risk for severe gusts. However, this is highly uncertain and with substantial model differences evident, no severe probabilities will be introduced. ...Intermountain West... Monsoon moisture is expected to linger over portions of the eastern Great Basin and central Rockies Friday ahead of a broad upper low. A shortwave trough within the southwesterly flow aloft will overspread the region near peak heating. The increase in ascent will support scattered thunderstorms over portions of the Intermountain West Friday afternoon and evening. While buoyancy will not be overly large (~500 J/kg of MLCAPE) and some remnant cloud cover/convection could overturn the air mass, increasingly strong southwesterly flow aloft could support a few stronger thunderstorms/clusters. With a fairly dry air mass in place, stronger downdrafts could be capable of isolated gusty winds given steep low-level lapse rates. ..Lyons.. 09/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Wed Sep 10 2025 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated storms are possible over parts of the Northern Plains and Upper Midwest with additional storms possible over the Rockies and Great Basin Friday. Severe potential is uncertain. ...Northern Plains and Upper Midwest... Shortwave ridging over the northern Plains and Upper Midwest is forecast to shift eastward Friday as weak troughing emerges from the Rockies. A modest increase in mid-level southwesterly flow will impinge upon rich low-level moisture near a weakening surface low and stalled warm front across the Dakotas and western MN. Low-level convergence near the low/front may serve as a focus for isolated thunderstorm development Friday afternoon and evening. Moderate MLCAPE around 2000 J/kg and steepening mid-level lapse rates could support a few stronger storms. Some enhancement of the mid-level flow may allow for a few storms to organize with some clustering and isolated strong outflow gusts. The primary uncertainty remains storm coverage with most guidance showing only sporadic convection through much of the day. An increase in convective coverage is possible overnight and into early Saturday as a 35-40 kt southerly low-level jet develops across the central Plains, bolstering low-level warm advection. Should this occur, one or more clusters of thunderstorms could propagate eastward along the warm front, potentially posing a risk for severe gusts. However, this is highly uncertain and with substantial model differences evident, no severe probabilities will be introduced. ...Intermountain West... Monsoon moisture is expected to linger over portions of the eastern Great Basin and central Rockies Friday ahead of a broad upper low. A shortwave trough within the southwesterly flow aloft will overspread the region near peak heating. The increase in ascent will support scattered thunderstorms over portions of the Intermountain West Friday afternoon and evening. While buoyancy will not be overly large (~500 J/kg of MLCAPE) and some remnant cloud cover/convection could overturn the air mass, increasingly strong southwesterly flow aloft could support a few stronger thunderstorms/clusters. With a fairly dry air mass in place, stronger downdrafts could be capable of isolated gusty winds given steep low-level lapse rates. ..Lyons.. 09/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Wed Sep 10 2025 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated storms are possible over parts of the Northern Plains and Upper Midwest with additional storms possible over the Rockies and Great Basin Friday. Severe potential is uncertain. ...Northern Plains and Upper Midwest... Shortwave ridging over the northern Plains and Upper Midwest is forecast to shift eastward Friday as weak troughing emerges from the Rockies. A modest increase in mid-level southwesterly flow will impinge upon rich low-level moisture near a weakening surface low and stalled warm front across the Dakotas and western MN. Low-level convergence near the low/front may serve as a focus for isolated thunderstorm development Friday afternoon and evening. Moderate MLCAPE around 2000 J/kg and steepening mid-level lapse rates could support a few stronger storms. Some enhancement of the mid-level flow may allow for a few storms to organize with some clustering and isolated strong outflow gusts. The primary uncertainty remains storm coverage with most guidance showing only sporadic convection through much of the day. An increase in convective coverage is possible overnight and into early Saturday as a 35-40 kt southerly low-level jet develops across the central Plains, bolstering low-level warm advection. Should this occur, one or more clusters of thunderstorms could propagate eastward along the warm front, potentially posing a risk for severe gusts. However, this is highly uncertain and with substantial model differences evident, no severe probabilities will be introduced. ...Intermountain West... Monsoon moisture is expected to linger over portions of the eastern Great Basin and central Rockies Friday ahead of a broad upper low. A shortwave trough within the southwesterly flow aloft will overspread the region near peak heating. The increase in ascent will support scattered thunderstorms over portions of the Intermountain West Friday afternoon and evening. While buoyancy will not be overly large (~500 J/kg of MLCAPE) and some remnant cloud cover/convection could overturn the air mass, increasingly strong southwesterly flow aloft could support a few stronger thunderstorms/clusters. With a fairly dry air mass in place, stronger downdrafts could be capable of isolated gusty winds given steep low-level lapse rates. ..Lyons.. 09/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Wed Sep 10 2025 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated storms are possible over parts of the Northern Plains and Upper Midwest with additional storms possible over the Rockies and Great Basin Friday. Severe potential is uncertain. ...Northern Plains and Upper Midwest... Shortwave ridging over the northern Plains and Upper Midwest is forecast to shift eastward Friday as weak troughing emerges from the Rockies. A modest increase in mid-level southwesterly flow will impinge upon rich low-level moisture near a weakening surface low and stalled warm front across the Dakotas and western MN. Low-level convergence near the low/front may serve as a focus for isolated thunderstorm development Friday afternoon and evening. Moderate MLCAPE around 2000 J/kg and steepening mid-level lapse rates could support a few stronger storms. Some enhancement of the mid-level flow may allow for a few storms to organize with some clustering and isolated strong outflow gusts. The primary uncertainty remains storm coverage with most guidance showing only sporadic convection through much of the day. An increase in convective coverage is possible overnight and into early Saturday as a 35-40 kt southerly low-level jet develops across the central Plains, bolstering low-level warm advection. Should this occur, one or more clusters of thunderstorms could propagate eastward along the warm front, potentially posing a risk for severe gusts. However, this is highly uncertain and with substantial model differences evident, no severe probabilities will be introduced. ...Intermountain West... Monsoon moisture is expected to linger over portions of the eastern Great Basin and central Rockies Friday ahead of a broad upper low. A shortwave trough within the southwesterly flow aloft will overspread the region near peak heating. The increase in ascent will support scattered thunderstorms over portions of the Intermountain West Friday afternoon and evening. While buoyancy will not be overly large (~500 J/kg of MLCAPE) and some remnant cloud cover/convection could overturn the air mass, increasingly strong southwesterly flow aloft could support a few stronger thunderstorms/clusters. With a fairly dry air mass in place, stronger downdrafts could be capable of isolated gusty winds given steep low-level lapse rates. ..Lyons.. 09/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Wed Sep 10 2025 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated storms are possible over parts of the Northern Plains and Upper Midwest with additional storms possible over the Rockies and Great Basin Friday. Severe potential is uncertain. ...Northern Plains and Upper Midwest... Shortwave ridging over the northern Plains and Upper Midwest is forecast to shift eastward Friday as weak troughing emerges from the Rockies. A modest increase in mid-level southwesterly flow will impinge upon rich low-level moisture near a weakening surface low and stalled warm front across the Dakotas and western MN. Low-level convergence near the low/front may serve as a focus for isolated thunderstorm development Friday afternoon and evening. Moderate MLCAPE around 2000 J/kg and steepening mid-level lapse rates could support a few stronger storms. Some enhancement of the mid-level flow may allow for a few storms to organize with some clustering and isolated strong outflow gusts. The primary uncertainty remains storm coverage with most guidance showing only sporadic convection through much of the day. An increase in convective coverage is possible overnight and into early Saturday as a 35-40 kt southerly low-level jet develops across the central Plains, bolstering low-level warm advection. Should this occur, one or more clusters of thunderstorms could propagate eastward along the warm front, potentially posing a risk for severe gusts. However, this is highly uncertain and with substantial model differences evident, no severe probabilities will be introduced. ...Intermountain West... Monsoon moisture is expected to linger over portions of the eastern Great Basin and central Rockies Friday ahead of a broad upper low. A shortwave trough within the southwesterly flow aloft will overspread the region near peak heating. The increase in ascent will support scattered thunderstorms over portions of the Intermountain West Friday afternoon and evening. While buoyancy will not be overly large (~500 J/kg of MLCAPE) and some remnant cloud cover/convection could overturn the air mass, increasingly strong southwesterly flow aloft could support a few stronger thunderstorms/clusters. With a fairly dry air mass in place, stronger downdrafts could be capable of isolated gusty winds given steep low-level lapse rates. ..Lyons.. 09/10/2025 Read more

MD 2057 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR CENTRAL HIGH PLAINS
Mesoscale Discussion 2057 NWS Storm Prediction Center Norman OK 1149 PM CDT Tue Sep 09 2025 Areas affected...Central High Plains Concerning...Severe potential...Watch possible Valid 100449Z - 100645Z Probability of Watch Issuance...40 percent SUMMARY...Isolated wind/hail threat can be expected with storms across the central High Plains into the early-morning hours. DISCUSSION...Sustained low-level warm advection across the central High Plains appears to be aiding an expanding complex of convection from southeast CO into southwest KS. Latest radar data suggests an MCS is evolving along the nose of an intensifying LLJ. The LLJ is expected to veer into south central KS later tonight as a weak disturbance ejects into this portion of the Plains. While the majority of this convection should struggle to attain severe levels, there is some concern for hail/gusty winds as mid-level lapse rates are steep. If a more organized bowing segment ultimately evolves with this maturing complex, a severe thunderstorm watch may be considered, but for now it is not anticipated. ..Darrow/Mosier.. 09/10/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...DDC...GLD...PUB... LAT...LON 39170243 38499863 37329873 37590108 38220280 39170243 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CDT Wed Sep 10 2025 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHERN AND CENTRAL HIGH PLAINS AND INTERMOUNTAIN WEST... ...SUMMARY... Isolated strong to severe thunderstorms with hail and severe wind potential are possible across Montana and the Dakotas. Additional isolated strong storms may develop over the central High Plains and Intermountain West. ...Northern and central Plains... South/southwesterly flow aloft is forecast to increase over the Northern Rockies/Plains ahead of a shortwave trough along the eastern periphery of a broader upper low. Weak height falls will overspread the western fringes of a moistening low-level air mass as a warm front moves northward with a surface cyclone over central MT. Low-level upslope is expected much of the day along and north of the front, which should result in moderate destabilization (MLCAPE ~1500-2500 J/kg). However, some inhibition is also expected given the glancing influence of the upper ascent and warm mid-level temperatures. Isolated to widely scattered thunderstorms are expected late in the afternoon along and north of the warm front from eastern MT into western ND. Steep mid-level lapse rates and veering wind profiles could support some supercell structures. It remain unclear if much of this activity will be surface based given the best ascent will be north of the front. Still, the degree of buoyancy and increasing deep-layer shear should support some risk for hail and severe gusts. Farther south, isolated storms are possible near a surface trough from eastern WY into western NE/SD. Forcing for ascent should be weaker with some residual capping likely limiting development within the warm sector. High-based storms may form within the drier air west over the terrain before gradually drifting eastward toward the richer surface moisture. With limited buoyancy and vertical shear, organized severe storms are unlikely, but isolated severe gusts are possible given the steep low-level lapse rates. ...Four Corners and Western Slope... A belt of stronger mid-level flow southeast of the upper low over the Great Basin will overspread a modified monsoon air mass in place over northern AZ/NM into western CO and eastern UT. Afternoon heating should result in a few hundred J/kg of MLCAPE above low-level inverted-V thermodynamic profiles. Isolated to widely scattered storms should develop and move off the higher terrain by mid morning. Some organization of these storms into clusters or transient supercells is expected owing to elongated mid-level hodographs beneath the stronger flow aloft. Given the steep low/mid-level lapse rates, isolated severe gusts and some small hail are possible with the stronger storms. ..Lyons.. 09/10/2025 Read more