Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1209 PM CDT Mon Aug 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF EASTERN WISCONSIN...UPPER AND LOWER MICHIGAN...AND PARTS OF NORTHEASTERN ILLINOIS...NORTHERN INDIANA...NORTHWESTERN OHIO... ...SUMMARY... Strong thunderstorms may impact parts of the upper Great Lakes region Tuesday into Tuesday evening, accompanied by at least some risk for severe wind and hail. ...Discussion... The westerlies will remain confined to the northern mid-latitudes, but models suggest that flow near/north of the Canadian/U.S. border will trend a bit more zonal, as an initially prominent mid-level high centered offshore of the Pacific Northwest continues to become suppressed west-southwestward across the northeastern Pacific. Within this regime, models continue to indicate the consolidation of several short wave perturbations into larger-scale mid-level troughing across Ontario into Quebec by late Tuesday night, accompanied by significant surface cyclogenesis across far northern Ontario into the southern Hudson/James Bay vicinity. In lower levels, a modest initial intrusion of cooler/drier air may overspread much of the Dakotas and portions of the Upper Midwest and adjacent Great Lakes region by 12Z Tuesday, before slowly advancing east-southeastward across the upper Great Lakes and eventually being overtaken by a more substantive cool intrusion later Tuesday through Tuesday night. Complicating matters with respect to destabilization, guidance continues to indicate that the lead front will be preceded by a stalled lingering remnant frontal zone, which may still be reinforced by convective precipitation/outflow across parts of southern Lower Michigan and northern Illinois, into the lower Missouri Valley and the southern Great Plains, at the outset of the period. ...Upper Great Lakes... Short wave developments within the evolving pattern remain unclear due to spread within the various model output, but guidance continues to indicate that one notable short wave impulse will continue digging across parts of the Upper Midwest and adjacent Great Lakes region during the day Tuesday, before pivoting across and east-northeast of Lake Huron/Georgian Bay. It appears that this may be preceded by one or two convectively generated perturbations which will become increasing sheared while merging into the southwesterly cyclonic mid-level regime overspreading the Great Lakes vicinity. As this occurs, various model output (notably including calibrated thunderstorm probability guidance from the High Resolution Ensemble system) suggests that destabilization and forcing for ascent will become supportive of a couple of corridors of increasing thunderstorm development by late Tuesday afternoon. These generally coincide with the stalled remnant frontal zone across parts of southeastern Lower Michigan into northeastern Illinois and the initial cold front advancing across Upper Michigan/eastern Wisconsin. Along the southern boundary, which may strengthen some with differential surface heating, mid-level thermodynamic profiles may be relatively warm with weak lapse rates. However, it still appears that seasonably high boundary-layer moisture content, coupled with daytime heating, will contribute to sizable CAPE. Coinciding with a belt of strengthening southwesterly lower/mid-level flow (including 30-40 kt in the 700-500 mb layer), the environment may become conducive to organized convection, including evolving supercell structures and upscale growing clusters with potential to produce strong to severe wind gusts by late Tuesday afternoon into evening. Across Upper Michigan into eastern Wisconsin, pre-frontal destabilization remains more unclear due to the possible influence of convective cloud cover and/or outflow. But, with breaks in cloud cover allowing for a narrow corridor of heating, cooling aloft and strengthening shear along the frontal zone might contribute to an environment conducive to strong thunderstorm development with potential to produce marginally severe hail and localized strong surface gusts late Tuesday afternoon. ...Southwest... Forecast deep-layer mean wind fields are generally light, but include a west-northwesterly upslope component to the low-level flow beneath north-northeasterly mid-level flow. This may aid propagation of convection off the higher terrain of southwestern New Mexico and southeastern Arizona, into lower elevations with a warm and deeply mixed boundary layer characterized by modest potential instability by late Tuesday afternoon. As this occurs, a few strong to severe downbursts and gusts along strengthening outflows appears possible. ..Kerr.. 08/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1209 PM CDT Mon Aug 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF EASTERN WISCONSIN...UPPER AND LOWER MICHIGAN...AND PARTS OF NORTHEASTERN ILLINOIS...NORTHERN INDIANA...NORTHWESTERN OHIO... ...SUMMARY... Strong thunderstorms may impact parts of the upper Great Lakes region Tuesday into Tuesday evening, accompanied by at least some risk for severe wind and hail. ...Discussion... The westerlies will remain confined to the northern mid-latitudes, but models suggest that flow near/north of the Canadian/U.S. border will trend a bit more zonal, as an initially prominent mid-level high centered offshore of the Pacific Northwest continues to become suppressed west-southwestward across the northeastern Pacific. Within this regime, models continue to indicate the consolidation of several short wave perturbations into larger-scale mid-level troughing across Ontario into Quebec by late Tuesday night, accompanied by significant surface cyclogenesis across far northern Ontario into the southern Hudson/James Bay vicinity. In lower levels, a modest initial intrusion of cooler/drier air may overspread much of the Dakotas and portions of the Upper Midwest and adjacent Great Lakes region by 12Z Tuesday, before slowly advancing east-southeastward across the upper Great Lakes and eventually being overtaken by a more substantive cool intrusion later Tuesday through Tuesday night. Complicating matters with respect to destabilization, guidance continues to indicate that the lead front will be preceded by a stalled lingering remnant frontal zone, which may still be reinforced by convective precipitation/outflow across parts of southern Lower Michigan and northern Illinois, into the lower Missouri Valley and the southern Great Plains, at the outset of the period. ...Upper Great Lakes... Short wave developments within the evolving pattern remain unclear due to spread within the various model output, but guidance continues to indicate that one notable short wave impulse will continue digging across parts of the Upper Midwest and adjacent Great Lakes region during the day Tuesday, before pivoting across and east-northeast of Lake Huron/Georgian Bay. It appears that this may be preceded by one or two convectively generated perturbations which will become increasing sheared while merging into the southwesterly cyclonic mid-level regime overspreading the Great Lakes vicinity. As this occurs, various model output (notably including calibrated thunderstorm probability guidance from the High Resolution Ensemble system) suggests that destabilization and forcing for ascent will become supportive of a couple of corridors of increasing thunderstorm development by late Tuesday afternoon. These generally coincide with the stalled remnant frontal zone across parts of southeastern Lower Michigan into northeastern Illinois and the initial cold front advancing across Upper Michigan/eastern Wisconsin. Along the southern boundary, which may strengthen some with differential surface heating, mid-level thermodynamic profiles may be relatively warm with weak lapse rates. However, it still appears that seasonably high boundary-layer moisture content, coupled with daytime heating, will contribute to sizable CAPE. Coinciding with a belt of strengthening southwesterly lower/mid-level flow (including 30-40 kt in the 700-500 mb layer), the environment may become conducive to organized convection, including evolving supercell structures and upscale growing clusters with potential to produce strong to severe wind gusts by late Tuesday afternoon into evening. Across Upper Michigan into eastern Wisconsin, pre-frontal destabilization remains more unclear due to the possible influence of convective cloud cover and/or outflow. But, with breaks in cloud cover allowing for a narrow corridor of heating, cooling aloft and strengthening shear along the frontal zone might contribute to an environment conducive to strong thunderstorm development with potential to produce marginally severe hail and localized strong surface gusts late Tuesday afternoon. ...Southwest... Forecast deep-layer mean wind fields are generally light, but include a west-northwesterly upslope component to the low-level flow beneath north-northeasterly mid-level flow. This may aid propagation of convection off the higher terrain of southwestern New Mexico and southeastern Arizona, into lower elevations with a warm and deeply mixed boundary layer characterized by modest potential instability by late Tuesday afternoon. As this occurs, a few strong to severe downbursts and gusts along strengthening outflows appears possible. ..Kerr.. 08/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1209 PM CDT Mon Aug 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF EASTERN WISCONSIN...UPPER AND LOWER MICHIGAN...AND PARTS OF NORTHEASTERN ILLINOIS...NORTHERN INDIANA...NORTHWESTERN OHIO... ...SUMMARY... Strong thunderstorms may impact parts of the upper Great Lakes region Tuesday into Tuesday evening, accompanied by at least some risk for severe wind and hail. ...Discussion... The westerlies will remain confined to the northern mid-latitudes, but models suggest that flow near/north of the Canadian/U.S. border will trend a bit more zonal, as an initially prominent mid-level high centered offshore of the Pacific Northwest continues to become suppressed west-southwestward across the northeastern Pacific. Within this regime, models continue to indicate the consolidation of several short wave perturbations into larger-scale mid-level troughing across Ontario into Quebec by late Tuesday night, accompanied by significant surface cyclogenesis across far northern Ontario into the southern Hudson/James Bay vicinity. In lower levels, a modest initial intrusion of cooler/drier air may overspread much of the Dakotas and portions of the Upper Midwest and adjacent Great Lakes region by 12Z Tuesday, before slowly advancing east-southeastward across the upper Great Lakes and eventually being overtaken by a more substantive cool intrusion later Tuesday through Tuesday night. Complicating matters with respect to destabilization, guidance continues to indicate that the lead front will be preceded by a stalled lingering remnant frontal zone, which may still be reinforced by convective precipitation/outflow across parts of southern Lower Michigan and northern Illinois, into the lower Missouri Valley and the southern Great Plains, at the outset of the period. ...Upper Great Lakes... Short wave developments within the evolving pattern remain unclear due to spread within the various model output, but guidance continues to indicate that one notable short wave impulse will continue digging across parts of the Upper Midwest and adjacent Great Lakes region during the day Tuesday, before pivoting across and east-northeast of Lake Huron/Georgian Bay. It appears that this may be preceded by one or two convectively generated perturbations which will become increasing sheared while merging into the southwesterly cyclonic mid-level regime overspreading the Great Lakes vicinity. As this occurs, various model output (notably including calibrated thunderstorm probability guidance from the High Resolution Ensemble system) suggests that destabilization and forcing for ascent will become supportive of a couple of corridors of increasing thunderstorm development by late Tuesday afternoon. These generally coincide with the stalled remnant frontal zone across parts of southeastern Lower Michigan into northeastern Illinois and the initial cold front advancing across Upper Michigan/eastern Wisconsin. Along the southern boundary, which may strengthen some with differential surface heating, mid-level thermodynamic profiles may be relatively warm with weak lapse rates. However, it still appears that seasonably high boundary-layer moisture content, coupled with daytime heating, will contribute to sizable CAPE. Coinciding with a belt of strengthening southwesterly lower/mid-level flow (including 30-40 kt in the 700-500 mb layer), the environment may become conducive to organized convection, including evolving supercell structures and upscale growing clusters with potential to produce strong to severe wind gusts by late Tuesday afternoon into evening. Across Upper Michigan into eastern Wisconsin, pre-frontal destabilization remains more unclear due to the possible influence of convective cloud cover and/or outflow. But, with breaks in cloud cover allowing for a narrow corridor of heating, cooling aloft and strengthening shear along the frontal zone might contribute to an environment conducive to strong thunderstorm development with potential to produce marginally severe hail and localized strong surface gusts late Tuesday afternoon. ...Southwest... Forecast deep-layer mean wind fields are generally light, but include a west-northwesterly upslope component to the low-level flow beneath north-northeasterly mid-level flow. This may aid propagation of convection off the higher terrain of southwestern New Mexico and southeastern Arizona, into lower elevations with a warm and deeply mixed boundary layer characterized by modest potential instability by late Tuesday afternoon. As this occurs, a few strong to severe downbursts and gusts along strengthening outflows appears possible. ..Kerr.. 08/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1209 PM CDT Mon Aug 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF EASTERN WISCONSIN...UPPER AND LOWER MICHIGAN...AND PARTS OF NORTHEASTERN ILLINOIS...NORTHERN INDIANA...NORTHWESTERN OHIO... ...SUMMARY... Strong thunderstorms may impact parts of the upper Great Lakes region Tuesday into Tuesday evening, accompanied by at least some risk for severe wind and hail. ...Discussion... The westerlies will remain confined to the northern mid-latitudes, but models suggest that flow near/north of the Canadian/U.S. border will trend a bit more zonal, as an initially prominent mid-level high centered offshore of the Pacific Northwest continues to become suppressed west-southwestward across the northeastern Pacific. Within this regime, models continue to indicate the consolidation of several short wave perturbations into larger-scale mid-level troughing across Ontario into Quebec by late Tuesday night, accompanied by significant surface cyclogenesis across far northern Ontario into the southern Hudson/James Bay vicinity. In lower levels, a modest initial intrusion of cooler/drier air may overspread much of the Dakotas and portions of the Upper Midwest and adjacent Great Lakes region by 12Z Tuesday, before slowly advancing east-southeastward across the upper Great Lakes and eventually being overtaken by a more substantive cool intrusion later Tuesday through Tuesday night. Complicating matters with respect to destabilization, guidance continues to indicate that the lead front will be preceded by a stalled lingering remnant frontal zone, which may still be reinforced by convective precipitation/outflow across parts of southern Lower Michigan and northern Illinois, into the lower Missouri Valley and the southern Great Plains, at the outset of the period. ...Upper Great Lakes... Short wave developments within the evolving pattern remain unclear due to spread within the various model output, but guidance continues to indicate that one notable short wave impulse will continue digging across parts of the Upper Midwest and adjacent Great Lakes region during the day Tuesday, before pivoting across and east-northeast of Lake Huron/Georgian Bay. It appears that this may be preceded by one or two convectively generated perturbations which will become increasing sheared while merging into the southwesterly cyclonic mid-level regime overspreading the Great Lakes vicinity. As this occurs, various model output (notably including calibrated thunderstorm probability guidance from the High Resolution Ensemble system) suggests that destabilization and forcing for ascent will become supportive of a couple of corridors of increasing thunderstorm development by late Tuesday afternoon. These generally coincide with the stalled remnant frontal zone across parts of southeastern Lower Michigan into northeastern Illinois and the initial cold front advancing across Upper Michigan/eastern Wisconsin. Along the southern boundary, which may strengthen some with differential surface heating, mid-level thermodynamic profiles may be relatively warm with weak lapse rates. However, it still appears that seasonably high boundary-layer moisture content, coupled with daytime heating, will contribute to sizable CAPE. Coinciding with a belt of strengthening southwesterly lower/mid-level flow (including 30-40 kt in the 700-500 mb layer), the environment may become conducive to organized convection, including evolving supercell structures and upscale growing clusters with potential to produce strong to severe wind gusts by late Tuesday afternoon into evening. Across Upper Michigan into eastern Wisconsin, pre-frontal destabilization remains more unclear due to the possible influence of convective cloud cover and/or outflow. But, with breaks in cloud cover allowing for a narrow corridor of heating, cooling aloft and strengthening shear along the frontal zone might contribute to an environment conducive to strong thunderstorm development with potential to produce marginally severe hail and localized strong surface gusts late Tuesday afternoon. ...Southwest... Forecast deep-layer mean wind fields are generally light, but include a west-northwesterly upslope component to the low-level flow beneath north-northeasterly mid-level flow. This may aid propagation of convection off the higher terrain of southwestern New Mexico and southeastern Arizona, into lower elevations with a warm and deeply mixed boundary layer characterized by modest potential instability by late Tuesday afternoon. As this occurs, a few strong to severe downbursts and gusts along strengthening outflows appears possible. ..Kerr.. 08/11/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Mon Aug 11 2025 Valid 111700Z - 121200Z Minor adjustments were made to the D1 Fire Weather Outlook Isolated Dry Thunderstorm area across Arizona in alignment with trends in recent guidance. See previous discussion below for more information. ..Thornton.. 08/11/2025 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Aug 11 2025/ ...Synopsis... Somewhat limited fire weather concerns are expected today across the Southwest/Four Corners region. Very dry conditions will persist across the eastern Great Basin/Four Corners with widespread 5-15% RH minimums expected this afternoon. However, low-level winds are expected to be somewhat weaker today compared to previous days as a surface high gradually builds across the Intermountain west. Sustained winds between 10-15 mph will likely be accompanied by 15-25 mph gusts by around peak heating when boundary-layer mixing will be maximized, but confidence in sustained elevated conditions remains too limited to warrant highlights. Instead, fire weather concerns will manifest as another day of dry thunderstorm potential along the Mogollon Rim. Lightning data and MRMS imagery from the past 24 hours shows a mixture of heavy precipitation cores (QPE values near 0.25 inch) as well as multiple dry lightning strikes. Additionally, a couple of small fire starts were noted over the past 24 hours due to lightning. Similar thermodynamic conditions will be in place this afternoon and will likely yield a similar mixture of wet and dry thunderstorms. Unlikely previous days, thunderstorm coverage may be more limited due to weaker synoptic-scale forcing for ascent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Mon Aug 11 2025 Valid 111700Z - 121200Z Minor adjustments were made to the D1 Fire Weather Outlook Isolated Dry Thunderstorm area across Arizona in alignment with trends in recent guidance. See previous discussion below for more information. ..Thornton.. 08/11/2025 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Aug 11 2025/ ...Synopsis... Somewhat limited fire weather concerns are expected today across the Southwest/Four Corners region. Very dry conditions will persist across the eastern Great Basin/Four Corners with widespread 5-15% RH minimums expected this afternoon. However, low-level winds are expected to be somewhat weaker today compared to previous days as a surface high gradually builds across the Intermountain west. Sustained winds between 10-15 mph will likely be accompanied by 15-25 mph gusts by around peak heating when boundary-layer mixing will be maximized, but confidence in sustained elevated conditions remains too limited to warrant highlights. Instead, fire weather concerns will manifest as another day of dry thunderstorm potential along the Mogollon Rim. Lightning data and MRMS imagery from the past 24 hours shows a mixture of heavy precipitation cores (QPE values near 0.25 inch) as well as multiple dry lightning strikes. Additionally, a couple of small fire starts were noted over the past 24 hours due to lightning. Similar thermodynamic conditions will be in place this afternoon and will likely yield a similar mixture of wet and dry thunderstorms. Unlikely previous days, thunderstorm coverage may be more limited due to weaker synoptic-scale forcing for ascent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Mon Aug 11 2025 Valid 111700Z - 121200Z Minor adjustments were made to the D1 Fire Weather Outlook Isolated Dry Thunderstorm area across Arizona in alignment with trends in recent guidance. See previous discussion below for more information. ..Thornton.. 08/11/2025 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Aug 11 2025/ ...Synopsis... Somewhat limited fire weather concerns are expected today across the Southwest/Four Corners region. Very dry conditions will persist across the eastern Great Basin/Four Corners with widespread 5-15% RH minimums expected this afternoon. However, low-level winds are expected to be somewhat weaker today compared to previous days as a surface high gradually builds across the Intermountain west. Sustained winds between 10-15 mph will likely be accompanied by 15-25 mph gusts by around peak heating when boundary-layer mixing will be maximized, but confidence in sustained elevated conditions remains too limited to warrant highlights. Instead, fire weather concerns will manifest as another day of dry thunderstorm potential along the Mogollon Rim. Lightning data and MRMS imagery from the past 24 hours shows a mixture of heavy precipitation cores (QPE values near 0.25 inch) as well as multiple dry lightning strikes. Additionally, a couple of small fire starts were noted over the past 24 hours due to lightning. Similar thermodynamic conditions will be in place this afternoon and will likely yield a similar mixture of wet and dry thunderstorms. Unlikely previous days, thunderstorm coverage may be more limited due to weaker synoptic-scale forcing for ascent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Mon Aug 11 2025 Valid 111700Z - 121200Z Minor adjustments were made to the D1 Fire Weather Outlook Isolated Dry Thunderstorm area across Arizona in alignment with trends in recent guidance. See previous discussion below for more information. ..Thornton.. 08/11/2025 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Aug 11 2025/ ...Synopsis... Somewhat limited fire weather concerns are expected today across the Southwest/Four Corners region. Very dry conditions will persist across the eastern Great Basin/Four Corners with widespread 5-15% RH minimums expected this afternoon. However, low-level winds are expected to be somewhat weaker today compared to previous days as a surface high gradually builds across the Intermountain west. Sustained winds between 10-15 mph will likely be accompanied by 15-25 mph gusts by around peak heating when boundary-layer mixing will be maximized, but confidence in sustained elevated conditions remains too limited to warrant highlights. Instead, fire weather concerns will manifest as another day of dry thunderstorm potential along the Mogollon Rim. Lightning data and MRMS imagery from the past 24 hours shows a mixture of heavy precipitation cores (QPE values near 0.25 inch) as well as multiple dry lightning strikes. Additionally, a couple of small fire starts were noted over the past 24 hours due to lightning. Similar thermodynamic conditions will be in place this afternoon and will likely yield a similar mixture of wet and dry thunderstorms. Unlikely previous days, thunderstorm coverage may be more limited due to weaker synoptic-scale forcing for ascent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Mon Aug 11 2025 Valid 111700Z - 121200Z Minor adjustments were made to the D1 Fire Weather Outlook Isolated Dry Thunderstorm area across Arizona in alignment with trends in recent guidance. See previous discussion below for more information. ..Thornton.. 08/11/2025 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Aug 11 2025/ ...Synopsis... Somewhat limited fire weather concerns are expected today across the Southwest/Four Corners region. Very dry conditions will persist across the eastern Great Basin/Four Corners with widespread 5-15% RH minimums expected this afternoon. However, low-level winds are expected to be somewhat weaker today compared to previous days as a surface high gradually builds across the Intermountain west. Sustained winds between 10-15 mph will likely be accompanied by 15-25 mph gusts by around peak heating when boundary-layer mixing will be maximized, but confidence in sustained elevated conditions remains too limited to warrant highlights. Instead, fire weather concerns will manifest as another day of dry thunderstorm potential along the Mogollon Rim. Lightning data and MRMS imagery from the past 24 hours shows a mixture of heavy precipitation cores (QPE values near 0.25 inch) as well as multiple dry lightning strikes. Additionally, a couple of small fire starts were noted over the past 24 hours due to lightning. Similar thermodynamic conditions will be in place this afternoon and will likely yield a similar mixture of wet and dry thunderstorms. Unlikely previous days, thunderstorm coverage may be more limited due to weaker synoptic-scale forcing for ascent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Mon Aug 11 2025 Valid 111700Z - 121200Z Minor adjustments were made to the D1 Fire Weather Outlook Isolated Dry Thunderstorm area across Arizona in alignment with trends in recent guidance. See previous discussion below for more information. ..Thornton.. 08/11/2025 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Aug 11 2025/ ...Synopsis... Somewhat limited fire weather concerns are expected today across the Southwest/Four Corners region. Very dry conditions will persist across the eastern Great Basin/Four Corners with widespread 5-15% RH minimums expected this afternoon. However, low-level winds are expected to be somewhat weaker today compared to previous days as a surface high gradually builds across the Intermountain west. Sustained winds between 10-15 mph will likely be accompanied by 15-25 mph gusts by around peak heating when boundary-layer mixing will be maximized, but confidence in sustained elevated conditions remains too limited to warrant highlights. Instead, fire weather concerns will manifest as another day of dry thunderstorm potential along the Mogollon Rim. Lightning data and MRMS imagery from the past 24 hours shows a mixture of heavy precipitation cores (QPE values near 0.25 inch) as well as multiple dry lightning strikes. Additionally, a couple of small fire starts were noted over the past 24 hours due to lightning. Similar thermodynamic conditions will be in place this afternoon and will likely yield a similar mixture of wet and dry thunderstorms. Unlikely previous days, thunderstorm coverage may be more limited due to weaker synoptic-scale forcing for ascent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Aug 11 2025 Valid 111630Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN GREAT PLAINS...LOWER MISSOURI VALLEY...AND UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Plains, lower Missouri Valley, and the Upper Midwest, mainly this afternoon and evening. ...Lower MO Valley... Visible satellite/radar composite shows an MCV moving east-northeastward over northeast KS late this morning. Regional WSR-88D VAD data shows an enhanced belt of 850-500 mb flow (40 kt in the 2-6 km layer) associated with this disturbance. Surface analysis places a surface low over the Flint Hills with backed easterly flow across eastern KS into northwest MO. Considerable mid- to high-level cloud debris from early morning convection will be slow to dissipate, but gradual filtering of sunlight and the initial signs of a stratocumulus field over the Flint Hills indicates destabilization is beginning to occur. Models vary considerably (understandably so) regarding the development/evolution of a few potential stronger thunderstorms across the lower MO Valley later this afternoon into the early evening. Some forecast soundings show modest enlargement of the low-level portion of the hodograph, which may support updraft rotation if vigorous updraft development occurs. Given the low probability for severe and potentially supportive environment, have introduced low-severe probabilities this outlook update. ...Southern Plains... Morning analysis shows an outflow reinforced front has advanced southward across the southern High Plains, but has stalled near the I-44 corridor in OK southwestward into the northern periphery of the Permian Basin. Water-vapor imagery shows a mid-level impulse moving across southern CO and embedded within larger-scale troughing from CO/NM into the Upper Midwest. This mid-level trough will gradually pivot eastward over the southern High Plains through the evening. Heating of an adequately moist boundary layer (dewpoints ranging from the lower 70s in central OK to the mid 50s in east-central NM) will yield moderate buoyancy near/north of the diffuse boundary. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms. Isolated large hail and severe gusts are the primary hazards with the stronger thunderstorms. ...North Dakota into Northern Minnesota... No change in thinking from the previous forecast. A mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ..Smith/Squitieri.. 08/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Aug 11 2025 Valid 111630Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN GREAT PLAINS...LOWER MISSOURI VALLEY...AND UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Plains, lower Missouri Valley, and the Upper Midwest, mainly this afternoon and evening. ...Lower MO Valley... Visible satellite/radar composite shows an MCV moving east-northeastward over northeast KS late this morning. Regional WSR-88D VAD data shows an enhanced belt of 850-500 mb flow (40 kt in the 2-6 km layer) associated with this disturbance. Surface analysis places a surface low over the Flint Hills with backed easterly flow across eastern KS into northwest MO. Considerable mid- to high-level cloud debris from early morning convection will be slow to dissipate, but gradual filtering of sunlight and the initial signs of a stratocumulus field over the Flint Hills indicates destabilization is beginning to occur. Models vary considerably (understandably so) regarding the development/evolution of a few potential stronger thunderstorms across the lower MO Valley later this afternoon into the early evening. Some forecast soundings show modest enlargement of the low-level portion of the hodograph, which may support updraft rotation if vigorous updraft development occurs. Given the low probability for severe and potentially supportive environment, have introduced low-severe probabilities this outlook update. ...Southern Plains... Morning analysis shows an outflow reinforced front has advanced southward across the southern High Plains, but has stalled near the I-44 corridor in OK southwestward into the northern periphery of the Permian Basin. Water-vapor imagery shows a mid-level impulse moving across southern CO and embedded within larger-scale troughing from CO/NM into the Upper Midwest. This mid-level trough will gradually pivot eastward over the southern High Plains through the evening. Heating of an adequately moist boundary layer (dewpoints ranging from the lower 70s in central OK to the mid 50s in east-central NM) will yield moderate buoyancy near/north of the diffuse boundary. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms. Isolated large hail and severe gusts are the primary hazards with the stronger thunderstorms. ...North Dakota into Northern Minnesota... No change in thinking from the previous forecast. A mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ..Smith/Squitieri.. 08/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Aug 11 2025 Valid 111630Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN GREAT PLAINS...LOWER MISSOURI VALLEY...AND UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Plains, lower Missouri Valley, and the Upper Midwest, mainly this afternoon and evening. ...Lower MO Valley... Visible satellite/radar composite shows an MCV moving east-northeastward over northeast KS late this morning. Regional WSR-88D VAD data shows an enhanced belt of 850-500 mb flow (40 kt in the 2-6 km layer) associated with this disturbance. Surface analysis places a surface low over the Flint Hills with backed easterly flow across eastern KS into northwest MO. Considerable mid- to high-level cloud debris from early morning convection will be slow to dissipate, but gradual filtering of sunlight and the initial signs of a stratocumulus field over the Flint Hills indicates destabilization is beginning to occur. Models vary considerably (understandably so) regarding the development/evolution of a few potential stronger thunderstorms across the lower MO Valley later this afternoon into the early evening. Some forecast soundings show modest enlargement of the low-level portion of the hodograph, which may support updraft rotation if vigorous updraft development occurs. Given the low probability for severe and potentially supportive environment, have introduced low-severe probabilities this outlook update. ...Southern Plains... Morning analysis shows an outflow reinforced front has advanced southward across the southern High Plains, but has stalled near the I-44 corridor in OK southwestward into the northern periphery of the Permian Basin. Water-vapor imagery shows a mid-level impulse moving across southern CO and embedded within larger-scale troughing from CO/NM into the Upper Midwest. This mid-level trough will gradually pivot eastward over the southern High Plains through the evening. Heating of an adequately moist boundary layer (dewpoints ranging from the lower 70s in central OK to the mid 50s in east-central NM) will yield moderate buoyancy near/north of the diffuse boundary. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms. Isolated large hail and severe gusts are the primary hazards with the stronger thunderstorms. ...North Dakota into Northern Minnesota... No change in thinking from the previous forecast. A mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ..Smith/Squitieri.. 08/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Aug 11 2025 Valid 111630Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN GREAT PLAINS...LOWER MISSOURI VALLEY...AND UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Plains, lower Missouri Valley, and the Upper Midwest, mainly this afternoon and evening. ...Lower MO Valley... Visible satellite/radar composite shows an MCV moving east-northeastward over northeast KS late this morning. Regional WSR-88D VAD data shows an enhanced belt of 850-500 mb flow (40 kt in the 2-6 km layer) associated with this disturbance. Surface analysis places a surface low over the Flint Hills with backed easterly flow across eastern KS into northwest MO. Considerable mid- to high-level cloud debris from early morning convection will be slow to dissipate, but gradual filtering of sunlight and the initial signs of a stratocumulus field over the Flint Hills indicates destabilization is beginning to occur. Models vary considerably (understandably so) regarding the development/evolution of a few potential stronger thunderstorms across the lower MO Valley later this afternoon into the early evening. Some forecast soundings show modest enlargement of the low-level portion of the hodograph, which may support updraft rotation if vigorous updraft development occurs. Given the low probability for severe and potentially supportive environment, have introduced low-severe probabilities this outlook update. ...Southern Plains... Morning analysis shows an outflow reinforced front has advanced southward across the southern High Plains, but has stalled near the I-44 corridor in OK southwestward into the northern periphery of the Permian Basin. Water-vapor imagery shows a mid-level impulse moving across southern CO and embedded within larger-scale troughing from CO/NM into the Upper Midwest. This mid-level trough will gradually pivot eastward over the southern High Plains through the evening. Heating of an adequately moist boundary layer (dewpoints ranging from the lower 70s in central OK to the mid 50s in east-central NM) will yield moderate buoyancy near/north of the diffuse boundary. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms. Isolated large hail and severe gusts are the primary hazards with the stronger thunderstorms. ...North Dakota into Northern Minnesota... No change in thinking from the previous forecast. A mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ..Smith/Squitieri.. 08/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Aug 11 2025 Valid 111630Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN GREAT PLAINS...LOWER MISSOURI VALLEY...AND UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Plains, lower Missouri Valley, and the Upper Midwest, mainly this afternoon and evening. ...Lower MO Valley... Visible satellite/radar composite shows an MCV moving east-northeastward over northeast KS late this morning. Regional WSR-88D VAD data shows an enhanced belt of 850-500 mb flow (40 kt in the 2-6 km layer) associated with this disturbance. Surface analysis places a surface low over the Flint Hills with backed easterly flow across eastern KS into northwest MO. Considerable mid- to high-level cloud debris from early morning convection will be slow to dissipate, but gradual filtering of sunlight and the initial signs of a stratocumulus field over the Flint Hills indicates destabilization is beginning to occur. Models vary considerably (understandably so) regarding the development/evolution of a few potential stronger thunderstorms across the lower MO Valley later this afternoon into the early evening. Some forecast soundings show modest enlargement of the low-level portion of the hodograph, which may support updraft rotation if vigorous updraft development occurs. Given the low probability for severe and potentially supportive environment, have introduced low-severe probabilities this outlook update. ...Southern Plains... Morning analysis shows an outflow reinforced front has advanced southward across the southern High Plains, but has stalled near the I-44 corridor in OK southwestward into the northern periphery of the Permian Basin. Water-vapor imagery shows a mid-level impulse moving across southern CO and embedded within larger-scale troughing from CO/NM into the Upper Midwest. This mid-level trough will gradually pivot eastward over the southern High Plains through the evening. Heating of an adequately moist boundary layer (dewpoints ranging from the lower 70s in central OK to the mid 50s in east-central NM) will yield moderate buoyancy near/north of the diffuse boundary. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms. Isolated large hail and severe gusts are the primary hazards with the stronger thunderstorms. ...North Dakota into Northern Minnesota... No change in thinking from the previous forecast. A mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ..Smith/Squitieri.. 08/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Aug 11 2025 Valid 111630Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN GREAT PLAINS...LOWER MISSOURI VALLEY...AND UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms are possible across parts of the southern Plains, lower Missouri Valley, and the Upper Midwest, mainly this afternoon and evening. ...Lower MO Valley... Visible satellite/radar composite shows an MCV moving east-northeastward over northeast KS late this morning. Regional WSR-88D VAD data shows an enhanced belt of 850-500 mb flow (40 kt in the 2-6 km layer) associated with this disturbance. Surface analysis places a surface low over the Flint Hills with backed easterly flow across eastern KS into northwest MO. Considerable mid- to high-level cloud debris from early morning convection will be slow to dissipate, but gradual filtering of sunlight and the initial signs of a stratocumulus field over the Flint Hills indicates destabilization is beginning to occur. Models vary considerably (understandably so) regarding the development/evolution of a few potential stronger thunderstorms across the lower MO Valley later this afternoon into the early evening. Some forecast soundings show modest enlargement of the low-level portion of the hodograph, which may support updraft rotation if vigorous updraft development occurs. Given the low probability for severe and potentially supportive environment, have introduced low-severe probabilities this outlook update. ...Southern Plains... Morning analysis shows an outflow reinforced front has advanced southward across the southern High Plains, but has stalled near the I-44 corridor in OK southwestward into the northern periphery of the Permian Basin. Water-vapor imagery shows a mid-level impulse moving across southern CO and embedded within larger-scale troughing from CO/NM into the Upper Midwest. This mid-level trough will gradually pivot eastward over the southern High Plains through the evening. Heating of an adequately moist boundary layer (dewpoints ranging from the lower 70s in central OK to the mid 50s in east-central NM) will yield moderate buoyancy near/north of the diffuse boundary. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms. Isolated large hail and severe gusts are the primary hazards with the stronger thunderstorms. ...North Dakota into Northern Minnesota... No change in thinking from the previous forecast. A mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ..Smith/Squitieri.. 08/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Aug 11 2025 Valid 111300Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...AND OVER PORTIONS OF NORTH DAKOTA INTO NORTHERN MINNESOTA... ...SUMMARY... Isolated strong to severe thunderstorms may pose some risk for severe winds and hail across parts of the southern Plains, and separately from North Dakota into northern Minnesota, mainly this afternoon and evening. ...Southern Plains... Convection has generally weakened this morning across eastern KS, with a outflow reinforced front advancing southward across the southern High Plains. This boundary is forecast to stall through the morning and early afternoon, and it will likely serve as a focus for renewed thunderstorm development later today. The southern extent of upper troughing that exists over much of the Plains is forecast to advance eastward across the southern High Plains this afternoon. Initial development over the higher terrain of north-central into northeast NM should occur in a modest low-level upslope flow regime, with steep lapse rates aloft contributing to moderate instability. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms developing with moderate to locally strong instability amid ample daytime heating. Isolated damaging winds via strong downbursts and marginally severe hail appear possible with the stronger cores given seasonably cool temperatures aloft (around -10C at 500 mb with the 12Z OUN observed sounding), and the Marginal Risk has been expanded eastward for this possibility. ...North Dakota into Northern Minnesota... Within upper troughing already established over the northern/central Plains and central Canada, a mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ...Missouri/Iowa... An MCV generated by overnight/early morning convection across the southern/central Plains should develop northeastward into parts of northern MO and IA by this afternoon. It remains unclear whether sufficient instability to support robust thunderstorms will be able to develop today ahead of this feature given ongoing convection and cloud debris. Regardless, some enhancement to the low/mid-level flow and related deep-layer shear could support updraft organization if surface-based thunderstorms can develop. Given the continued uncertainty regarding this potential, have held off on inclusion of low severe probabilities across this region with this update. ..Gleason/Leitman.. 08/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Aug 11 2025 Valid 111300Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...AND OVER PORTIONS OF NORTH DAKOTA INTO NORTHERN MINNESOTA... ...SUMMARY... Isolated strong to severe thunderstorms may pose some risk for severe winds and hail across parts of the southern Plains, and separately from North Dakota into northern Minnesota, mainly this afternoon and evening. ...Southern Plains... Convection has generally weakened this morning across eastern KS, with a outflow reinforced front advancing southward across the southern High Plains. This boundary is forecast to stall through the morning and early afternoon, and it will likely serve as a focus for renewed thunderstorm development later today. The southern extent of upper troughing that exists over much of the Plains is forecast to advance eastward across the southern High Plains this afternoon. Initial development over the higher terrain of north-central into northeast NM should occur in a modest low-level upslope flow regime, with steep lapse rates aloft contributing to moderate instability. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms developing with moderate to locally strong instability amid ample daytime heating. Isolated damaging winds via strong downbursts and marginally severe hail appear possible with the stronger cores given seasonably cool temperatures aloft (around -10C at 500 mb with the 12Z OUN observed sounding), and the Marginal Risk has been expanded eastward for this possibility. ...North Dakota into Northern Minnesota... Within upper troughing already established over the northern/central Plains and central Canada, a mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ...Missouri/Iowa... An MCV generated by overnight/early morning convection across the southern/central Plains should develop northeastward into parts of northern MO and IA by this afternoon. It remains unclear whether sufficient instability to support robust thunderstorms will be able to develop today ahead of this feature given ongoing convection and cloud debris. Regardless, some enhancement to the low/mid-level flow and related deep-layer shear could support updraft organization if surface-based thunderstorms can develop. Given the continued uncertainty regarding this potential, have held off on inclusion of low severe probabilities across this region with this update. ..Gleason/Leitman.. 08/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Aug 11 2025 Valid 111300Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...AND OVER PORTIONS OF NORTH DAKOTA INTO NORTHERN MINNESOTA... ...SUMMARY... Isolated strong to severe thunderstorms may pose some risk for severe winds and hail across parts of the southern Plains, and separately from North Dakota into northern Minnesota, mainly this afternoon and evening. ...Southern Plains... Convection has generally weakened this morning across eastern KS, with a outflow reinforced front advancing southward across the southern High Plains. This boundary is forecast to stall through the morning and early afternoon, and it will likely serve as a focus for renewed thunderstorm development later today. The southern extent of upper troughing that exists over much of the Plains is forecast to advance eastward across the southern High Plains this afternoon. Initial development over the higher terrain of north-central into northeast NM should occur in a modest low-level upslope flow regime, with steep lapse rates aloft contributing to moderate instability. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms developing with moderate to locally strong instability amid ample daytime heating. Isolated damaging winds via strong downbursts and marginally severe hail appear possible with the stronger cores given seasonably cool temperatures aloft (around -10C at 500 mb with the 12Z OUN observed sounding), and the Marginal Risk has been expanded eastward for this possibility. ...North Dakota into Northern Minnesota... Within upper troughing already established over the northern/central Plains and central Canada, a mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ...Missouri/Iowa... An MCV generated by overnight/early morning convection across the southern/central Plains should develop northeastward into parts of northern MO and IA by this afternoon. It remains unclear whether sufficient instability to support robust thunderstorms will be able to develop today ahead of this feature given ongoing convection and cloud debris. Regardless, some enhancement to the low/mid-level flow and related deep-layer shear could support updraft organization if surface-based thunderstorms can develop. Given the continued uncertainty regarding this potential, have held off on inclusion of low severe probabilities across this region with this update. ..Gleason/Leitman.. 08/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Aug 11 2025 Valid 111300Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS...AND OVER PORTIONS OF NORTH DAKOTA INTO NORTHERN MINNESOTA... ...SUMMARY... Isolated strong to severe thunderstorms may pose some risk for severe winds and hail across parts of the southern Plains, and separately from North Dakota into northern Minnesota, mainly this afternoon and evening. ...Southern Plains... Convection has generally weakened this morning across eastern KS, with a outflow reinforced front advancing southward across the southern High Plains. This boundary is forecast to stall through the morning and early afternoon, and it will likely serve as a focus for renewed thunderstorm development later today. The southern extent of upper troughing that exists over much of the Plains is forecast to advance eastward across the southern High Plains this afternoon. Initial development over the higher terrain of north-central into northeast NM should occur in a modest low-level upslope flow regime, with steep lapse rates aloft contributing to moderate instability. Weak low-level winds will gradually veer to west-northwesterly and modestly strengthen with height through mid/upper levels, supporting modest deep-layer shear and some updraft organization. Isolated severe hail may occur with initially more cellular development across the southern High Plains, before some clustering potentially occurs late this afternoon/evening farther east into the TX Panhandle and northwest TX with more of a wind threat. While deep-layer shear will likely remain weak farther east across OK, the front/outflow boundary should aid in at least scattered thunderstorms developing with moderate to locally strong instability amid ample daytime heating. Isolated damaging winds via strong downbursts and marginally severe hail appear possible with the stronger cores given seasonably cool temperatures aloft (around -10C at 500 mb with the 12Z OUN observed sounding), and the Marginal Risk has been expanded eastward for this possibility. ...North Dakota into Northern Minnesota... Within upper troughing already established over the northern/central Plains and central Canada, a mid-level shortwave trough and related surface cold front are forecast to move east-southeastward over ND and northern MN through the period. Modest low-level moisture characterized by mid 50s to perhaps low 60s surface dewpoints should be present ahead of the front across these areas. Diurnal heating and modestly steepened lapse rates aloft should aid in the development of weak instability this afternoon. Thunderstorms should gradually increase in coverage along/ahead of the front this afternoon/evening as they spread eastward over parts of ND into northern MN. The stronger cells may produce marginally severe hail, with sufficient deep-layer shear present for some convective organization. With time, some clustering/upscale growth along the front appears probable, with isolated strong to severe gusts possible. The lack of stronger instability should tend to temper the overall severe threat. ...Missouri/Iowa... An MCV generated by overnight/early morning convection across the southern/central Plains should develop northeastward into parts of northern MO and IA by this afternoon. It remains unclear whether sufficient instability to support robust thunderstorms will be able to develop today ahead of this feature given ongoing convection and cloud debris. Regardless, some enhancement to the low/mid-level flow and related deep-layer shear could support updraft organization if surface-based thunderstorms can develop. Given the continued uncertainty regarding this potential, have held off on inclusion of low severe probabilities across this region with this update. ..Gleason/Leitman.. 08/11/2025 Read more