Severe Storms

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Jul 10 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE UPPER GREAT LAKES AND ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS SOUTHEAST TOWARD THE TEXAS HILL COUNTRY... ...SUMMARY... Marginally severe thunderstorms will be possible across portions of the Upper Great Lakes during much of the day on Saturday. Additional strong-to-severe thunderstorms will be possible across the central and southern High Plains southeastward toward the Texas Hill Country. ... Upper Great Lakes ... Multiple vorticity maxima will coalesce into a singular short-wave trough across the region on Saturday. This amalgamation of vorticity will take on an increasingly negative tilt as this feature moves through the basal region of a broad Canadian trough. As this occurs, the upper-level jet core downstream of the Canadian trough will strengthen, placing much of the Upper Great lakes within the right entrance region of the jet. Thus, multiple bands of strong to severe thunderstorms are expected to develop along and ahead of a surface cold front in response to this increasing large-scale ascent. Most-unstable CAPE values between 1000-2000 J/kg and effective-layer shear between 30-40 knots will support at least some potential for damaging thunderstorm winds. ... Central High Plains southeast toward the Texas Hill Country ... Thunderstorms will be ongoing across portions of the southern Great Plains throughout the forecast period along a stalled frontal boundary. Although an isolated severe thunderstorm cannot be ruled out along the frontal boundary, the greatest chance of organized severe thunderstorms will develop during the late afternoon across the higher terrain of central and southern Colorado. Here, moist upslope flow at the surface coupled with modest north-northwesterly flow aloft should aid in the development of an MCS during the afternoon and evening. This MCS should move south-southeast during the overnight hours across portions of the Oklahoma and Texas Panhandles eventually approaching the Texas Hill Country by the end of the forecast period. ..Marsh.. 07/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Jul 10 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE UPPER GREAT LAKES AND ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS SOUTHEAST TOWARD THE TEXAS HILL COUNTRY... ...SUMMARY... Marginally severe thunderstorms will be possible across portions of the Upper Great Lakes during much of the day on Saturday. Additional strong-to-severe thunderstorms will be possible across the central and southern High Plains southeastward toward the Texas Hill Country. ... Upper Great Lakes ... Multiple vorticity maxima will coalesce into a singular short-wave trough across the region on Saturday. This amalgamation of vorticity will take on an increasingly negative tilt as this feature moves through the basal region of a broad Canadian trough. As this occurs, the upper-level jet core downstream of the Canadian trough will strengthen, placing much of the Upper Great lakes within the right entrance region of the jet. Thus, multiple bands of strong to severe thunderstorms are expected to develop along and ahead of a surface cold front in response to this increasing large-scale ascent. Most-unstable CAPE values between 1000-2000 J/kg and effective-layer shear between 30-40 knots will support at least some potential for damaging thunderstorm winds. ... Central High Plains southeast toward the Texas Hill Country ... Thunderstorms will be ongoing across portions of the southern Great Plains throughout the forecast period along a stalled frontal boundary. Although an isolated severe thunderstorm cannot be ruled out along the frontal boundary, the greatest chance of organized severe thunderstorms will develop during the late afternoon across the higher terrain of central and southern Colorado. Here, moist upslope flow at the surface coupled with modest north-northwesterly flow aloft should aid in the development of an MCS during the afternoon and evening. This MCS should move south-southeast during the overnight hours across portions of the Oklahoma and Texas Panhandles eventually approaching the Texas Hill Country by the end of the forecast period. ..Marsh.. 07/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Jul 10 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE UPPER GREAT LAKES AND ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS SOUTHEAST TOWARD THE TEXAS HILL COUNTRY... ...SUMMARY... Marginally severe thunderstorms will be possible across portions of the Upper Great Lakes during much of the day on Saturday. Additional strong-to-severe thunderstorms will be possible across the central and southern High Plains southeastward toward the Texas Hill Country. ... Upper Great Lakes ... Multiple vorticity maxima will coalesce into a singular short-wave trough across the region on Saturday. This amalgamation of vorticity will take on an increasingly negative tilt as this feature moves through the basal region of a broad Canadian trough. As this occurs, the upper-level jet core downstream of the Canadian trough will strengthen, placing much of the Upper Great lakes within the right entrance region of the jet. Thus, multiple bands of strong to severe thunderstorms are expected to develop along and ahead of a surface cold front in response to this increasing large-scale ascent. Most-unstable CAPE values between 1000-2000 J/kg and effective-layer shear between 30-40 knots will support at least some potential for damaging thunderstorm winds. ... Central High Plains southeast toward the Texas Hill Country ... Thunderstorms will be ongoing across portions of the southern Great Plains throughout the forecast period along a stalled frontal boundary. Although an isolated severe thunderstorm cannot be ruled out along the frontal boundary, the greatest chance of organized severe thunderstorms will develop during the late afternoon across the higher terrain of central and southern Colorado. Here, moist upslope flow at the surface coupled with modest north-northwesterly flow aloft should aid in the development of an MCS during the afternoon and evening. This MCS should move south-southeast during the overnight hours across portions of the Oklahoma and Texas Panhandles eventually approaching the Texas Hill Country by the end of the forecast period. ..Marsh.. 07/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Jul 10 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE UPPER GREAT LAKES AND ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS SOUTHEAST TOWARD THE TEXAS HILL COUNTRY... ...SUMMARY... Marginally severe thunderstorms will be possible across portions of the Upper Great Lakes during much of the day on Saturday. Additional strong-to-severe thunderstorms will be possible across the central and southern High Plains southeastward toward the Texas Hill Country. ... Upper Great Lakes ... Multiple vorticity maxima will coalesce into a singular short-wave trough across the region on Saturday. This amalgamation of vorticity will take on an increasingly negative tilt as this feature moves through the basal region of a broad Canadian trough. As this occurs, the upper-level jet core downstream of the Canadian trough will strengthen, placing much of the Upper Great lakes within the right entrance region of the jet. Thus, multiple bands of strong to severe thunderstorms are expected to develop along and ahead of a surface cold front in response to this increasing large-scale ascent. Most-unstable CAPE values between 1000-2000 J/kg and effective-layer shear between 30-40 knots will support at least some potential for damaging thunderstorm winds. ... Central High Plains southeast toward the Texas Hill Country ... Thunderstorms will be ongoing across portions of the southern Great Plains throughout the forecast period along a stalled frontal boundary. Although an isolated severe thunderstorm cannot be ruled out along the frontal boundary, the greatest chance of organized severe thunderstorms will develop during the late afternoon across the higher terrain of central and southern Colorado. Here, moist upslope flow at the surface coupled with modest north-northwesterly flow aloft should aid in the development of an MCS during the afternoon and evening. This MCS should move south-southeast during the overnight hours across portions of the Oklahoma and Texas Panhandles eventually approaching the Texas Hill Country by the end of the forecast period. ..Marsh.. 07/10/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Jul 10 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE UPPER GREAT LAKES AND ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS SOUTHEAST TOWARD THE TEXAS HILL COUNTRY... ...SUMMARY... Marginally severe thunderstorms will be possible across portions of the Upper Great Lakes during much of the day on Saturday. Additional strong-to-severe thunderstorms will be possible across the central and southern High Plains southeastward toward the Texas Hill Country. ... Upper Great Lakes ... Multiple vorticity maxima will coalesce into a singular short-wave trough across the region on Saturday. This amalgamation of vorticity will take on an increasingly negative tilt as this feature moves through the basal region of a broad Canadian trough. As this occurs, the upper-level jet core downstream of the Canadian trough will strengthen, placing much of the Upper Great lakes within the right entrance region of the jet. Thus, multiple bands of strong to severe thunderstorms are expected to develop along and ahead of a surface cold front in response to this increasing large-scale ascent. Most-unstable CAPE values between 1000-2000 J/kg and effective-layer shear between 30-40 knots will support at least some potential for damaging thunderstorm winds. ... Central High Plains southeast toward the Texas Hill Country ... Thunderstorms will be ongoing across portions of the southern Great Plains throughout the forecast period along a stalled frontal boundary. Although an isolated severe thunderstorm cannot be ruled out along the frontal boundary, the greatest chance of organized severe thunderstorms will develop during the late afternoon across the higher terrain of central and southern Colorado. Here, moist upslope flow at the surface coupled with modest north-northwesterly flow aloft should aid in the development of an MCS during the afternoon and evening. This MCS should move south-southeast during the overnight hours across portions of the Oklahoma and Texas Panhandles eventually approaching the Texas Hill Country by the end of the forecast period. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 10 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST KANSAS TO NORTHWEST ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are possible, mainly late afternoon and evening on Friday, from northeast Kansas to eastern Iowa and northwest Illinois. ... Central Great Plains to Midwest ... A positive-tilt trough will be moving across the northern Plains through the forecast period. To the south, a low-amplitude short-wave trough will be moving through the central Great Plains. At the same time, a diffuse/weak surface cold front will push east/southeast through the Plains. At the start of the forecast period one or more decaying MCSs should be ongoing across portions of Iowa perhaps into northern Illinois to perhaps as far east as lower Michigan. These MCSs could pose a residual risk for at least isolated wind damage through the morning. During the mid-to-late afternoon, additional thunderstorms are expected to develop in the wake of the morning convection. At this time guidance supports multiple initiation points across the area, the precise locations of which will be strongly influenced by the evolution of the morning convection. At this time, the most likely scenario is for initial thunderstorms to develop across southeast Iowa or northern Missouri along the residual outflow boundary from the morning convection. A second area of initiation is likely farther to the west along the diffuse surface cold front in Nebraska or northeast Kansas, perhaps extending northward into Minnesota. In both areas, strong instability may result in rapid thunderstorm development capable of producing strong wind and large hail. Given the degree of instability and an existing boundary, a tornado or two may also be possible, especially with initial thunderstorm development. With time, expectation is that these convective clusters will grow upscale as they move east and the primary severe threat should transition to severe wind gusts. ... High Plains ... Thunderstorms are expected to develop in the late afternoon. These storms will eventually grow upscale and move southeast toward the Great Plains. An isolated severe wind threat will be possible with any of these storms. ... Eastern US ... A warm, moist, weakly capped airmass will be in place across much of the east. Despite the absence of pronounced foci for initiation, widely scattered to scattered thunderstorms should develop during the late morning into the afternoon hours. Deep-layer shear should remain weak and precipitable water values will be lower than in preceding days. However, the potential will exist for scattered water-loaded downbursts capable of producing isolated wind damage. ..Marsh.. 07/10/2025 Read more

MD 1624 CONCERNING SEVERE THUNDERSTORM WATCH 500... FOR PORTIONS OF THE NORTHERN AND CENTRAL PLAINS
Mesoscale Discussion 1624 NWS Storm Prediction Center Norman OK 1118 PM CDT Wed Jul 09 2025 Areas affected...Portions of the northern and central Plains Concerning...Severe Thunderstorm Watch 500... Valid 100418Z - 100615Z The severe weather threat for Severe Thunderstorm Watch 500 continues. SUMMARY...Gusty winds will continue to be noted along the leading edge of squall line. DISCUSSION...Weak short-wave trough has topped the northern High Plains ridge and is now turning southeast across the eastern Dakotas. This feature appears to be partly responsible for a near 500 mi broken squall line that is propagating across the eastern portions of the northern and central Plains. Isolated severe wind gusts continue along the leading edge of this linear MCS, but much of this convection is producing sub-severe gusts. This activity should continue propagating through the remainder of ww500 with an attendant risk for at least isolated severe, and a local extension may be warranted. ..Darrow.. 07/10/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...FGF...FSD...OAX...ABR...GID... LAT...LON 40759925 42029784 43309760 44899762 47759768 47639675 45299645 42389643 40609759 40759925 MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 10 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF WESTERN AND CENTRAL KANSAS...CENTRAL AND EASTERN NEBRASKA...WESTERN IOWA AND PARTS OF SOUTHEASTERN SOUTH DAKOTA... ...SUMMARY... Strong thunderstorms posing a risk for severe hail, damaging wind gusts and perhaps a couple of tornadoes are possible late this afternoon into tonight across parts of the central Great Plains into mid Missouri Valley. ...Discussion... Stronger westerlies will remain confined to the higher latitudes through this period, with one significant short wave perturbation forecast to accelerate from eastern portions of the Canadian Northwest Territories through areas northeast of Hudson Bay, accompanied by a deepening surface cyclone. It appears that the leading edge of cooler, drier air in the wake of this cyclone will advance south of the international border into the northern Rockies and through adjacent portions of the northern U.S. Great Plains, trailed by another notable mid-level short wave impulse, which models indicate will dig near/east of the Canadian through northern U.S. Rockies. As this occurs, mid-level troughing within weaker flow in lower latitudes is forecast to slowly dig from the northern Great Basin toward the central Great Plains, suppressing stronger ridging in the subtropical to southern mid-latitudes, initially centered over the Southwest. This will be preceded by a couple of convectively generated or augmented perturbations migrating across the mid Missouri Valley and Upper Midwest, a modest mid-level trough slowly turning east-northeast of the lower Great Lakes vicinity, and several weak perturbations progressing through broad, weak cyclonic flow across the Southeast through southern Atlantic Seaboard. ...Great Plains into Midwest... Uncertainties remain concerning potential convective evolution through this period. Models suggest that surface boundaries may remain relatively diffuse, but residual seasonably moist boundary-layer air may become characterized by sizable CAPE with daytime heating, beneath steep lower/mid-tropospheric lapse rates, including warm elevated mixed layer air. There does appear at least a somewhat consistent signal within various convection allowing guidance that an MCV associated with ongoing convection across parts of the middle Missouri Valley could provide a focus for strong thunderstorm development later today across parts of the Upper Midwest. Otherwise, in advance of the digging upstream troughing, models indicate that a modest belt of southwesterly low-level flow (including 20-30+ kt in the 850-700 mb layer) will generally persist through the day east of the lee surface trough, from the Texas Panhandle/South Plains into the middle Missouri Valley. It appears that this will coincide with a corridor of stronger heating/deeper boundary-layer mixing across the higher plains, where thunderstorm activity initiating during the late afternoon may pose a risk for damaging wind gusts. Within the more moist low-level environment across eastern Nebraska into western Iowa, the wind fields, aided by veering with height, might become at least marginally conducive to a couple of supercells, in the presence of sizable CAPE, before forcing for ascent associated with the approaching mid-level trough tends to support upscale growing clusters this evening. ...Upper Ohio Valley into portions of New England... Near the southern periphery of the mid-level troughing shifting east or east-northeast of the lower Great Lakes region, models indicate that scattered thunderstorm development is probable during peak afternoon heating, in the presence of moderate CAPE (1000-2000+ J/kg) and shear enhanced at least somewhat by a belt of 20-30 kt westerly mid-level flow. This environment may become conducive to small hail and potentially damaging wind gusts, before activity weakens this evening. ...Southeast/Southern Atlantic Seaboard... Aided by forcing for ascent associated with the mid-level perturbations, in the presence of weak mid-level inhibition, one or two upscale growing clusters of storms may overspread the southern Atlantic Piedmont and coastal plain late this afternoon and evening. Forecast soundings indicate that a seasonably moist environment may become characterized by moderate CAPE, with perhaps a sufficient degree of sub-saturation to allow for evaporative cooling in downdrafts to contribute to modest surface cold pool development. In the presence of weak deep-layer southwesterly mean flow on the order of 10-15 kt, the potential for development of sufficiently strong rear inflow to support surface gusts in excess of 50 kt appears low, but even with peak gusts generally on the order of 35-50 kt, sporadic damage will still be possible. ..Kerr/Weinman.. 07/10/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 10 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF WESTERN AND CENTRAL KANSAS...CENTRAL AND EASTERN NEBRASKA...WESTERN IOWA AND PARTS OF SOUTHEASTERN SOUTH DAKOTA... ...SUMMARY... Strong thunderstorms posing a risk for severe hail, damaging wind gusts and perhaps a couple of tornadoes are possible late this afternoon into tonight across parts of the central Great Plains into mid Missouri Valley. ...Discussion... Stronger westerlies will remain confined to the higher latitudes through this period, with one significant short wave perturbation forecast to accelerate from eastern portions of the Canadian Northwest Territories through areas northeast of Hudson Bay, accompanied by a deepening surface cyclone. It appears that the leading edge of cooler, drier air in the wake of this cyclone will advance south of the international border into the northern Rockies and through adjacent portions of the northern U.S. Great Plains, trailed by another notable mid-level short wave impulse, which models indicate will dig near/east of the Canadian through northern U.S. Rockies. As this occurs, mid-level troughing within weaker flow in lower latitudes is forecast to slowly dig from the northern Great Basin toward the central Great Plains, suppressing stronger ridging in the subtropical to southern mid-latitudes, initially centered over the Southwest. This will be preceded by a couple of convectively generated or augmented perturbations migrating across the mid Missouri Valley and Upper Midwest, a modest mid-level trough slowly turning east-northeast of the lower Great Lakes vicinity, and several weak perturbations progressing through broad, weak cyclonic flow across the Southeast through southern Atlantic Seaboard. ...Great Plains into Midwest... Uncertainties remain concerning potential convective evolution through this period. Models suggest that surface boundaries may remain relatively diffuse, but residual seasonably moist boundary-layer air may become characterized by sizable CAPE with daytime heating, beneath steep lower/mid-tropospheric lapse rates, including warm elevated mixed layer air. There does appear at least a somewhat consistent signal within various convection allowing guidance that an MCV associated with ongoing convection across parts of the middle Missouri Valley could provide a focus for strong thunderstorm development later today across parts of the Upper Midwest. Otherwise, in advance of the digging upstream troughing, models indicate that a modest belt of southwesterly low-level flow (including 20-30+ kt in the 850-700 mb layer) will generally persist through the day east of the lee surface trough, from the Texas Panhandle/South Plains into the middle Missouri Valley. It appears that this will coincide with a corridor of stronger heating/deeper boundary-layer mixing across the higher plains, where thunderstorm activity initiating during the late afternoon may pose a risk for damaging wind gusts. Within the more moist low-level environment across eastern Nebraska into western Iowa, the wind fields, aided by veering with height, might become at least marginally conducive to a couple of supercells, in the presence of sizable CAPE, before forcing for ascent associated with the approaching mid-level trough tends to support upscale growing clusters this evening. ...Upper Ohio Valley into portions of New England... Near the southern periphery of the mid-level troughing shifting east or east-northeast of the lower Great Lakes region, models indicate that scattered thunderstorm development is probable during peak afternoon heating, in the presence of moderate CAPE (1000-2000+ J/kg) and shear enhanced at least somewhat by a belt of 20-30 kt westerly mid-level flow. This environment may become conducive to small hail and potentially damaging wind gusts, before activity weakens this evening. ...Southeast/Southern Atlantic Seaboard... Aided by forcing for ascent associated with the mid-level perturbations, in the presence of weak mid-level inhibition, one or two upscale growing clusters of storms may overspread the southern Atlantic Piedmont and coastal plain late this afternoon and evening. Forecast soundings indicate that a seasonably moist environment may become characterized by moderate CAPE, with perhaps a sufficient degree of sub-saturation to allow for evaporative cooling in downdrafts to contribute to modest surface cold pool development. In the presence of weak deep-layer southwesterly mean flow on the order of 10-15 kt, the potential for development of sufficiently strong rear inflow to support surface gusts in excess of 50 kt appears low, but even with peak gusts generally on the order of 35-50 kt, sporadic damage will still be possible. ..Kerr/Weinman.. 07/10/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 10 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF WESTERN AND CENTRAL KANSAS...CENTRAL AND EASTERN NEBRASKA...WESTERN IOWA AND PARTS OF SOUTHEASTERN SOUTH DAKOTA... ...SUMMARY... Strong thunderstorms posing a risk for severe hail, damaging wind gusts and perhaps a couple of tornadoes are possible late this afternoon into tonight across parts of the central Great Plains into mid Missouri Valley. ...Discussion... Stronger westerlies will remain confined to the higher latitudes through this period, with one significant short wave perturbation forecast to accelerate from eastern portions of the Canadian Northwest Territories through areas northeast of Hudson Bay, accompanied by a deepening surface cyclone. It appears that the leading edge of cooler, drier air in the wake of this cyclone will advance south of the international border into the northern Rockies and through adjacent portions of the northern U.S. Great Plains, trailed by another notable mid-level short wave impulse, which models indicate will dig near/east of the Canadian through northern U.S. Rockies. As this occurs, mid-level troughing within weaker flow in lower latitudes is forecast to slowly dig from the northern Great Basin toward the central Great Plains, suppressing stronger ridging in the subtropical to southern mid-latitudes, initially centered over the Southwest. This will be preceded by a couple of convectively generated or augmented perturbations migrating across the mid Missouri Valley and Upper Midwest, a modest mid-level trough slowly turning east-northeast of the lower Great Lakes vicinity, and several weak perturbations progressing through broad, weak cyclonic flow across the Southeast through southern Atlantic Seaboard. ...Great Plains into Midwest... Uncertainties remain concerning potential convective evolution through this period. Models suggest that surface boundaries may remain relatively diffuse, but residual seasonably moist boundary-layer air may become characterized by sizable CAPE with daytime heating, beneath steep lower/mid-tropospheric lapse rates, including warm elevated mixed layer air. There does appear at least a somewhat consistent signal within various convection allowing guidance that an MCV associated with ongoing convection across parts of the middle Missouri Valley could provide a focus for strong thunderstorm development later today across parts of the Upper Midwest. Otherwise, in advance of the digging upstream troughing, models indicate that a modest belt of southwesterly low-level flow (including 20-30+ kt in the 850-700 mb layer) will generally persist through the day east of the lee surface trough, from the Texas Panhandle/South Plains into the middle Missouri Valley. It appears that this will coincide with a corridor of stronger heating/deeper boundary-layer mixing across the higher plains, where thunderstorm activity initiating during the late afternoon may pose a risk for damaging wind gusts. Within the more moist low-level environment across eastern Nebraska into western Iowa, the wind fields, aided by veering with height, might become at least marginally conducive to a couple of supercells, in the presence of sizable CAPE, before forcing for ascent associated with the approaching mid-level trough tends to support upscale growing clusters this evening. ...Upper Ohio Valley into portions of New England... Near the southern periphery of the mid-level troughing shifting east or east-northeast of the lower Great Lakes region, models indicate that scattered thunderstorm development is probable during peak afternoon heating, in the presence of moderate CAPE (1000-2000+ J/kg) and shear enhanced at least somewhat by a belt of 20-30 kt westerly mid-level flow. This environment may become conducive to small hail and potentially damaging wind gusts, before activity weakens this evening. ...Southeast/Southern Atlantic Seaboard... Aided by forcing for ascent associated with the mid-level perturbations, in the presence of weak mid-level inhibition, one or two upscale growing clusters of storms may overspread the southern Atlantic Piedmont and coastal plain late this afternoon and evening. Forecast soundings indicate that a seasonably moist environment may become characterized by moderate CAPE, with perhaps a sufficient degree of sub-saturation to allow for evaporative cooling in downdrafts to contribute to modest surface cold pool development. In the presence of weak deep-layer southwesterly mean flow on the order of 10-15 kt, the potential for development of sufficiently strong rear inflow to support surface gusts in excess of 50 kt appears low, but even with peak gusts generally on the order of 35-50 kt, sporadic damage will still be possible. ..Kerr/Weinman.. 07/10/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 10 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF WESTERN AND CENTRAL KANSAS...CENTRAL AND EASTERN NEBRASKA...WESTERN IOWA AND PARTS OF SOUTHEASTERN SOUTH DAKOTA... ...SUMMARY... Strong thunderstorms posing a risk for severe hail, damaging wind gusts and perhaps a couple of tornadoes are possible late this afternoon into tonight across parts of the central Great Plains into mid Missouri Valley. ...Discussion... Stronger westerlies will remain confined to the higher latitudes through this period, with one significant short wave perturbation forecast to accelerate from eastern portions of the Canadian Northwest Territories through areas northeast of Hudson Bay, accompanied by a deepening surface cyclone. It appears that the leading edge of cooler, drier air in the wake of this cyclone will advance south of the international border into the northern Rockies and through adjacent portions of the northern U.S. Great Plains, trailed by another notable mid-level short wave impulse, which models indicate will dig near/east of the Canadian through northern U.S. Rockies. As this occurs, mid-level troughing within weaker flow in lower latitudes is forecast to slowly dig from the northern Great Basin toward the central Great Plains, suppressing stronger ridging in the subtropical to southern mid-latitudes, initially centered over the Southwest. This will be preceded by a couple of convectively generated or augmented perturbations migrating across the mid Missouri Valley and Upper Midwest, a modest mid-level trough slowly turning east-northeast of the lower Great Lakes vicinity, and several weak perturbations progressing through broad, weak cyclonic flow across the Southeast through southern Atlantic Seaboard. ...Great Plains into Midwest... Uncertainties remain concerning potential convective evolution through this period. Models suggest that surface boundaries may remain relatively diffuse, but residual seasonably moist boundary-layer air may become characterized by sizable CAPE with daytime heating, beneath steep lower/mid-tropospheric lapse rates, including warm elevated mixed layer air. There does appear at least a somewhat consistent signal within various convection allowing guidance that an MCV associated with ongoing convection across parts of the middle Missouri Valley could provide a focus for strong thunderstorm development later today across parts of the Upper Midwest. Otherwise, in advance of the digging upstream troughing, models indicate that a modest belt of southwesterly low-level flow (including 20-30+ kt in the 850-700 mb layer) will generally persist through the day east of the lee surface trough, from the Texas Panhandle/South Plains into the middle Missouri Valley. It appears that this will coincide with a corridor of stronger heating/deeper boundary-layer mixing across the higher plains, where thunderstorm activity initiating during the late afternoon may pose a risk for damaging wind gusts. Within the more moist low-level environment across eastern Nebraska into western Iowa, the wind fields, aided by veering with height, might become at least marginally conducive to a couple of supercells, in the presence of sizable CAPE, before forcing for ascent associated with the approaching mid-level trough tends to support upscale growing clusters this evening. ...Upper Ohio Valley into portions of New England... Near the southern periphery of the mid-level troughing shifting east or east-northeast of the lower Great Lakes region, models indicate that scattered thunderstorm development is probable during peak afternoon heating, in the presence of moderate CAPE (1000-2000+ J/kg) and shear enhanced at least somewhat by a belt of 20-30 kt westerly mid-level flow. This environment may become conducive to small hail and potentially damaging wind gusts, before activity weakens this evening. ...Southeast/Southern Atlantic Seaboard... Aided by forcing for ascent associated with the mid-level perturbations, in the presence of weak mid-level inhibition, one or two upscale growing clusters of storms may overspread the southern Atlantic Piedmont and coastal plain late this afternoon and evening. Forecast soundings indicate that a seasonably moist environment may become characterized by moderate CAPE, with perhaps a sufficient degree of sub-saturation to allow for evaporative cooling in downdrafts to contribute to modest surface cold pool development. In the presence of weak deep-layer southwesterly mean flow on the order of 10-15 kt, the potential for development of sufficiently strong rear inflow to support surface gusts in excess of 50 kt appears low, but even with peak gusts generally on the order of 35-50 kt, sporadic damage will still be possible. ..Kerr/Weinman.. 07/10/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 10 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF WESTERN AND CENTRAL KANSAS...CENTRAL AND EASTERN NEBRASKA...WESTERN IOWA AND PARTS OF SOUTHEASTERN SOUTH DAKOTA... ...SUMMARY... Strong thunderstorms posing a risk for severe hail, damaging wind gusts and perhaps a couple of tornadoes are possible late this afternoon into tonight across parts of the central Great Plains into mid Missouri Valley. ...Discussion... Stronger westerlies will remain confined to the higher latitudes through this period, with one significant short wave perturbation forecast to accelerate from eastern portions of the Canadian Northwest Territories through areas northeast of Hudson Bay, accompanied by a deepening surface cyclone. It appears that the leading edge of cooler, drier air in the wake of this cyclone will advance south of the international border into the northern Rockies and through adjacent portions of the northern U.S. Great Plains, trailed by another notable mid-level short wave impulse, which models indicate will dig near/east of the Canadian through northern U.S. Rockies. As this occurs, mid-level troughing within weaker flow in lower latitudes is forecast to slowly dig from the northern Great Basin toward the central Great Plains, suppressing stronger ridging in the subtropical to southern mid-latitudes, initially centered over the Southwest. This will be preceded by a couple of convectively generated or augmented perturbations migrating across the mid Missouri Valley and Upper Midwest, a modest mid-level trough slowly turning east-northeast of the lower Great Lakes vicinity, and several weak perturbations progressing through broad, weak cyclonic flow across the Southeast through southern Atlantic Seaboard. ...Great Plains into Midwest... Uncertainties remain concerning potential convective evolution through this period. Models suggest that surface boundaries may remain relatively diffuse, but residual seasonably moist boundary-layer air may become characterized by sizable CAPE with daytime heating, beneath steep lower/mid-tropospheric lapse rates, including warm elevated mixed layer air. There does appear at least a somewhat consistent signal within various convection allowing guidance that an MCV associated with ongoing convection across parts of the middle Missouri Valley could provide a focus for strong thunderstorm development later today across parts of the Upper Midwest. Otherwise, in advance of the digging upstream troughing, models indicate that a modest belt of southwesterly low-level flow (including 20-30+ kt in the 850-700 mb layer) will generally persist through the day east of the lee surface trough, from the Texas Panhandle/South Plains into the middle Missouri Valley. It appears that this will coincide with a corridor of stronger heating/deeper boundary-layer mixing across the higher plains, where thunderstorm activity initiating during the late afternoon may pose a risk for damaging wind gusts. Within the more moist low-level environment across eastern Nebraska into western Iowa, the wind fields, aided by veering with height, might become at least marginally conducive to a couple of supercells, in the presence of sizable CAPE, before forcing for ascent associated with the approaching mid-level trough tends to support upscale growing clusters this evening. ...Upper Ohio Valley into portions of New England... Near the southern periphery of the mid-level troughing shifting east or east-northeast of the lower Great Lakes region, models indicate that scattered thunderstorm development is probable during peak afternoon heating, in the presence of moderate CAPE (1000-2000+ J/kg) and shear enhanced at least somewhat by a belt of 20-30 kt westerly mid-level flow. This environment may become conducive to small hail and potentially damaging wind gusts, before activity weakens this evening. ...Southeast/Southern Atlantic Seaboard... Aided by forcing for ascent associated with the mid-level perturbations, in the presence of weak mid-level inhibition, one or two upscale growing clusters of storms may overspread the southern Atlantic Piedmont and coastal plain late this afternoon and evening. Forecast soundings indicate that a seasonably moist environment may become characterized by moderate CAPE, with perhaps a sufficient degree of sub-saturation to allow for evaporative cooling in downdrafts to contribute to modest surface cold pool development. In the presence of weak deep-layer southwesterly mean flow on the order of 10-15 kt, the potential for development of sufficiently strong rear inflow to support surface gusts in excess of 50 kt appears low, but even with peak gusts generally on the order of 35-50 kt, sporadic damage will still be possible. ..Kerr/Weinman.. 07/10/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1253 AM CDT Thu Jul 10 2025 Valid 101200Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT ACROSS PARTS OF WESTERN AND CENTRAL KANSAS...CENTRAL AND EASTERN NEBRASKA...WESTERN IOWA AND PARTS OF SOUTHEASTERN SOUTH DAKOTA... ...SUMMARY... Strong thunderstorms posing a risk for severe hail, damaging wind gusts and perhaps a couple of tornadoes are possible late this afternoon into tonight across parts of the central Great Plains into mid Missouri Valley. ...Discussion... Stronger westerlies will remain confined to the higher latitudes through this period, with one significant short wave perturbation forecast to accelerate from eastern portions of the Canadian Northwest Territories through areas northeast of Hudson Bay, accompanied by a deepening surface cyclone. It appears that the leading edge of cooler, drier air in the wake of this cyclone will advance south of the international border into the northern Rockies and through adjacent portions of the northern U.S. Great Plains, trailed by another notable mid-level short wave impulse, which models indicate will dig near/east of the Canadian through northern U.S. Rockies. As this occurs, mid-level troughing within weaker flow in lower latitudes is forecast to slowly dig from the northern Great Basin toward the central Great Plains, suppressing stronger ridging in the subtropical to southern mid-latitudes, initially centered over the Southwest. This will be preceded by a couple of convectively generated or augmented perturbations migrating across the mid Missouri Valley and Upper Midwest, a modest mid-level trough slowly turning east-northeast of the lower Great Lakes vicinity, and several weak perturbations progressing through broad, weak cyclonic flow across the Southeast through southern Atlantic Seaboard. ...Great Plains into Midwest... Uncertainties remain concerning potential convective evolution through this period. Models suggest that surface boundaries may remain relatively diffuse, but residual seasonably moist boundary-layer air may become characterized by sizable CAPE with daytime heating, beneath steep lower/mid-tropospheric lapse rates, including warm elevated mixed layer air. There does appear at least a somewhat consistent signal within various convection allowing guidance that an MCV associated with ongoing convection across parts of the middle Missouri Valley could provide a focus for strong thunderstorm development later today across parts of the Upper Midwest. Otherwise, in advance of the digging upstream troughing, models indicate that a modest belt of southwesterly low-level flow (including 20-30+ kt in the 850-700 mb layer) will generally persist through the day east of the lee surface trough, from the Texas Panhandle/South Plains into the middle Missouri Valley. It appears that this will coincide with a corridor of stronger heating/deeper boundary-layer mixing across the higher plains, where thunderstorm activity initiating during the late afternoon may pose a risk for damaging wind gusts. Within the more moist low-level environment across eastern Nebraska into western Iowa, the wind fields, aided by veering with height, might become at least marginally conducive to a couple of supercells, in the presence of sizable CAPE, before forcing for ascent associated with the approaching mid-level trough tends to support upscale growing clusters this evening. ...Upper Ohio Valley into portions of New England... Near the southern periphery of the mid-level troughing shifting east or east-northeast of the lower Great Lakes region, models indicate that scattered thunderstorm development is probable during peak afternoon heating, in the presence of moderate CAPE (1000-2000+ J/kg) and shear enhanced at least somewhat by a belt of 20-30 kt westerly mid-level flow. This environment may become conducive to small hail and potentially damaging wind gusts, before activity weakens this evening. ...Southeast/Southern Atlantic Seaboard... Aided by forcing for ascent associated with the mid-level perturbations, in the presence of weak mid-level inhibition, one or two upscale growing clusters of storms may overspread the southern Atlantic Piedmont and coastal plain late this afternoon and evening. Forecast soundings indicate that a seasonably moist environment may become characterized by moderate CAPE, with perhaps a sufficient degree of sub-saturation to allow for evaporative cooling in downdrafts to contribute to modest surface cold pool development. In the presence of weak deep-layer southwesterly mean flow on the order of 10-15 kt, the potential for development of sufficiently strong rear inflow to support surface gusts in excess of 50 kt appears low, but even with peak gusts generally on the order of 35-50 kt, sporadic damage will still be possible. ..Kerr/Weinman.. 07/10/2025 Read more