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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Tue Jul 02 2024 Valid 021630Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN/CENTRAL IOWA...NORTHERN MISSOURI...NORTHEAST KANSAS...AND SOUTHEAST NEBRASKA... ...SUMMARY... Scattered to numerous damaging thunderstorm winds, a few tornadoes, and occasional large hail appear most likely this afternoon and early evening over parts of southern/central Iowa, northern Missouri, and northeastern Kansas. ...Iowa/Missouri into Northeast Kansas and Vicinity... Elevated thunderstorms with a marginal/isolated hail threat are ongoing late this morning across eastern NE and southern IA in a low-level warm advection regime. This activity is also being aided by modest large-scale ascent associated with a subtle mid-level vorticity maximum moving eastward over the central Plains. The primary upper cyclone and related surface low will remain over central Canada today, with a cold front extending southward over the northern Plains/Upper Midwest and continuing southwestward into the central Plains. An effective warm front extends northeastward from a secondary surface low in north-central KS across northern MO into southern IA. This boundary will likely serve as a focus for severe thunderstorms this afternoon and evening as it attempts to lift further northward into IA. The 12Z sounding from TOP showed a very moist boundary layer, with precipitable water values through the column greater than 2 inches and somewhat steepened mid-level lapse rates. Robust daytime heating of this airmass along/south of the front will likely aid the development of moderate to strong instability by mid afternoon, even though mid-level temperature remain somewhat warm. A belt of stronger (40-55 kt) southwesterly mid-level flow associated with the subtle central Plains shortwave trough will likely overspread the frontal zone across IA and northern MO in the same time frame. With sufficient veering/strengthening of the wind field with height through mid-levels, around 35-50 kt of deep-layer shear is expected to promote organized convection, including the potential for both supercells and a bowing cluster. Thunderstorms should intensify by early to mid afternoon near the front across southeast NE/northeast KS into southern/central IA and perhaps northern MO. If this initial development can remain at least semi-discrete for a few hours, then sufficient low-level shear near the warm front would support a threat for a few tornadoes. Isolated severe hail may also occur with any sustained supercell. Otherwise, upscale growth into an MCS by mid to late afternoon appears likely given the mainly linear/frontal forcing and mid-level flow aligned mostly parallel to the surface front. Scattered to numerous damaging winds generally ranging 60-70 mph should become the primary severe hazard by late afternoon and early evening across IA and northern MO, but embedded QLCS circulations will also be possible. Convection should tend to weaken later this evening as it approaches the MS River and encounters a less unstable airmass. ...Southern/Central Plains... Additional convection should develop along the front with southwestward extent into KS and the southern/central High Plains. Given a well-mixed boundary layer and steepened low-level lapse rates with daytime heating, isolated to scattered severe/damaging winds should be the main threat with this activity. Modest low-level upslope flow in the post-frontal regime may encourage the development of isolated supercells across parts of southeast CO and vicinity. Occasional large hail and severe wind gusts may occur with any intense convection that can persist, but confidence in a small bowing cluster developing from this activity this evening remains low. Other occasionally strong to severe convection may develop southeastward from eastern WY into western NE this afternoon and evening. Weaker instability across this region should keep the overall severe threat rather isolated. ..Gleason/Thornton.. 07/02/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Tue Jul 02 2024 Valid 021300Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHERN IOWA...NORTHERN MISSOURI...NORTHEASTERN KANSAS...AND EXTREME SOUTHEASTERN NEBRASKA... ...SUMMARY... Damaging thunderstorm winds, a few tornadoes, and large hail are most likely this afternoon and early evening over southern Iowa, northern Missouri, and northeastern Kansas. ...Synopsis... Broadly cyclonic flow in mid/upper levels will persist from the Pacific Northwest across the central/northern Rockies to the Upper Great Lakes. Within that, a series of shortwave troughs were apparent, the most prominent over the CONUS being located initially across WY and northeastern UT. This perturbation should move eastward to eastern SD and central NE by 00Z, cross the upper Mississippi Valley overnight, and reach parts of WI and the Upper Peninsula of MI by the end of the period. As that occurs, a persistent subtropical high over the Arklatex region will shift eastward over the Delta region, but with attached ridging expanding back across central and west TX to near ELP. Another attached ridge will shift eastward across the Ohio Valley and Lower Great Lakes. At the surface, 11Z analysis showed a surface low near HLC, with cold front southwestward across extreme southeastern CO and northeastern/north-central NM. A warm front arched from the low across southeastern NE, then southward near the KS/MO and AR/OK borders. The warm front should move northeastward to the mid Mississippi Valley today while the low moves northeastward and weakens. Meanwhile, by 00Z, the cold front should reach western IA, northeastern through south-central KS, and the northern TX Panhandle. becoming a warm front into a deepening low over southeastern CO. By 12Z, the cold front should reach northern IL, central/southwestern MO, north-central OK, then into the low, which will have sagged into the northern TX Panhandle. ...IA/MO/northeastern KS and vicinity... A swath of decaying convection and associated cloud shield are ongoing from Lower MI to IA and parts of southeastern NE and northwestern MO. This plume of clouds/precip should continue to shift east-northeastward and erode through the day, but leave behind an outflow/differential-heating boundary that, southwest of the synoptic warm front, should act as the primary convective influence ahead of the cold front. Convergence near these boundaries, and strong heating in the richly moist warm sector between, will support scattered afternoon thunderstorms. This will include the potential for a few supercells with tornado and large-hail threats, whether relatively discrete early in the convective cycle, or embedded in subsequent quasi-linear evolution. That upscale convective organization also will maximize severe-wind potential from late afternoon into early evening, before activity encounters a more-stable, nocturnally cooling airmass farther east near the warm-frontal thermal gradient. In the preconvective warm sector, 70s F surface dewpoints should be common, as a Gulf-origin airmass blends with areas of evapotranspirative moisture contribution. Though mid/upper-level lapse rates will be modest, strong low-level destabilization will combine with a deep troposphere to contribute to MLCAPE in the 2000-3000 J/kg range. Effective-shear magnitudes will have a large range -- roughly 35-55 kt based strongly on boundary effects upon near-surface winds. Boundary-layer shear/hodographs will be greatest near the warm front and along any mesoscale boundaries between the fronts, locally maximizing supercell organization in low levels. ...Central/southern High Plains... Widely scattered to scattered thunderstorms are forecast to develop this afternoon over western portions of this area -- initially over relatively high elevations of southeast WY, east-central/ southeastern CO and northeastern NM, where diurnal heating will preferentially erode MLCINH. This activity should move generally eastward onto the adjoining High Plains, offering sporadic severe gusts and hail. The greatest concentration of convection (and associated severe potential) still appears most probable over southeastern CO, growing upscale as a complex and moving into parts of southwestern KS this evening. Vertical shear will be most favorable for supercells north of the front, where a substantial easterly component of boundary-layer flow will contribute to enhanced low-level shear, greater storm-relative low-level winds, upslope lift, and moist advection (to offset mixing-related moisture loss somewhat). The northern lobe of the (marginal) outlook area will be under the greatest mid/upper-level flow and strongest deep shear, but also will have weaker low-level moisture/theta-e and less buoyancy than farther south, with similar mid/upper-level lapse rates under a monsoonal plume as closer to the subtropical ridge. In the Arkansas River Valley region, activity moving into 50s to low 60s F surface dewpoints, with a strongly heated boundary layer, will encounter peak diurnal MLCAPE of 500-1500 J/kg across southeastern CO, and 1000-2000 J/kg into southwestern KS, amidst 45-55 kt effective-shear magnitudes, and long/nearly straight low-level hodographs favoring large hail with any discrete supercells. However, a well-mixed subcloud layer should support severe outflow and aggregation of outflows, leading to upscale clustering for a few hours before activity encounters too much CINH to remain severe over southern/central KS. Farther south, along and south of the front, deep-layer flow and shear will be weaker, as will buoyancy (due to drier, deeper mixed layers), but convection still may pose a threat for isolated severe downbursts. ..Edwards/Kerr.. 07/02/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Tue Jul 02 2024 Valid 021300Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHERN IOWA...NORTHERN MISSOURI...NORTHEASTERN KANSAS...AND EXTREME SOUTHEASTERN NEBRASKA... ...SUMMARY... Damaging thunderstorm winds, a few tornadoes, and large hail are most likely this afternoon and early evening over southern Iowa, northern Missouri, and northeastern Kansas. ...Synopsis... Broadly cyclonic flow in mid/upper levels will persist from the Pacific Northwest across the central/northern Rockies to the Upper Great Lakes. Within that, a series of shortwave troughs were apparent, the most prominent over the CONUS being located initially across WY and northeastern UT. This perturbation should move eastward to eastern SD and central NE by 00Z, cross the upper Mississippi Valley overnight, and reach parts of WI and the Upper Peninsula of MI by the end of the period. As that occurs, a persistent subtropical high over the Arklatex region will shift eastward over the Delta region, but with attached ridging expanding back across central and west TX to near ELP. Another attached ridge will shift eastward across the Ohio Valley and Lower Great Lakes. At the surface, 11Z analysis showed a surface low near HLC, with cold front southwestward across extreme southeastern CO and northeastern/north-central NM. A warm front arched from the low across southeastern NE, then southward near the KS/MO and AR/OK borders. The warm front should move northeastward to the mid Mississippi Valley today while the low moves northeastward and weakens. Meanwhile, by 00Z, the cold front should reach western IA, northeastern through south-central KS, and the northern TX Panhandle. becoming a warm front into a deepening low over southeastern CO. By 12Z, the cold front should reach northern IL, central/southwestern MO, north-central OK, then into the low, which will have sagged into the northern TX Panhandle. ...IA/MO/northeastern KS and vicinity... A swath of decaying convection and associated cloud shield are ongoing from Lower MI to IA and parts of southeastern NE and northwestern MO. This plume of clouds/precip should continue to shift east-northeastward and erode through the day, but leave behind an outflow/differential-heating boundary that, southwest of the synoptic warm front, should act as the primary convective influence ahead of the cold front. Convergence near these boundaries, and strong heating in the richly moist warm sector between, will support scattered afternoon thunderstorms. This will include the potential for a few supercells with tornado and large-hail threats, whether relatively discrete early in the convective cycle, or embedded in subsequent quasi-linear evolution. That upscale convective organization also will maximize severe-wind potential from late afternoon into early evening, before activity encounters a more-stable, nocturnally cooling airmass farther east near the warm-frontal thermal gradient. In the preconvective warm sector, 70s F surface dewpoints should be common, as a Gulf-origin airmass blends with areas of evapotranspirative moisture contribution. Though mid/upper-level lapse rates will be modest, strong low-level destabilization will combine with a deep troposphere to contribute to MLCAPE in the 2000-3000 J/kg range. Effective-shear magnitudes will have a large range -- roughly 35-55 kt based strongly on boundary effects upon near-surface winds. Boundary-layer shear/hodographs will be greatest near the warm front and along any mesoscale boundaries between the fronts, locally maximizing supercell organization in low levels. ...Central/southern High Plains... Widely scattered to scattered thunderstorms are forecast to develop this afternoon over western portions of this area -- initially over relatively high elevations of southeast WY, east-central/ southeastern CO and northeastern NM, where diurnal heating will preferentially erode MLCINH. This activity should move generally eastward onto the adjoining High Plains, offering sporadic severe gusts and hail. The greatest concentration of convection (and associated severe potential) still appears most probable over southeastern CO, growing upscale as a complex and moving into parts of southwestern KS this evening. Vertical shear will be most favorable for supercells north of the front, where a substantial easterly component of boundary-layer flow will contribute to enhanced low-level shear, greater storm-relative low-level winds, upslope lift, and moist advection (to offset mixing-related moisture loss somewhat). The northern lobe of the (marginal) outlook area will be under the greatest mid/upper-level flow and strongest deep shear, but also will have weaker low-level moisture/theta-e and less buoyancy than farther south, with similar mid/upper-level lapse rates under a monsoonal plume as closer to the subtropical ridge. In the Arkansas River Valley region, activity moving into 50s to low 60s F surface dewpoints, with a strongly heated boundary layer, will encounter peak diurnal MLCAPE of 500-1500 J/kg across southeastern CO, and 1000-2000 J/kg into southwestern KS, amidst 45-55 kt effective-shear magnitudes, and long/nearly straight low-level hodographs favoring large hail with any discrete supercells. However, a well-mixed subcloud layer should support severe outflow and aggregation of outflows, leading to upscale clustering for a few hours before activity encounters too much CINH to remain severe over southern/central KS. Farther south, along and south of the front, deep-layer flow and shear will be weaker, as will buoyancy (due to drier, deeper mixed layers), but convection still may pose a threat for isolated severe downbursts. ..Edwards/Kerr.. 07/02/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Tue Jul 02 2024 Valid 021300Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHERN IOWA...NORTHERN MISSOURI...NORTHEASTERN KANSAS...AND EXTREME SOUTHEASTERN NEBRASKA... ...SUMMARY... Damaging thunderstorm winds, a few tornadoes, and large hail are most likely this afternoon and early evening over southern Iowa, northern Missouri, and northeastern Kansas. ...Synopsis... Broadly cyclonic flow in mid/upper levels will persist from the Pacific Northwest across the central/northern Rockies to the Upper Great Lakes. Within that, a series of shortwave troughs were apparent, the most prominent over the CONUS being located initially across WY and northeastern UT. This perturbation should move eastward to eastern SD and central NE by 00Z, cross the upper Mississippi Valley overnight, and reach parts of WI and the Upper Peninsula of MI by the end of the period. As that occurs, a persistent subtropical high over the Arklatex region will shift eastward over the Delta region, but with attached ridging expanding back across central and west TX to near ELP. Another attached ridge will shift eastward across the Ohio Valley and Lower Great Lakes. At the surface, 11Z analysis showed a surface low near HLC, with cold front southwestward across extreme southeastern CO and northeastern/north-central NM. A warm front arched from the low across southeastern NE, then southward near the KS/MO and AR/OK borders. The warm front should move northeastward to the mid Mississippi Valley today while the low moves northeastward and weakens. Meanwhile, by 00Z, the cold front should reach western IA, northeastern through south-central KS, and the northern TX Panhandle. becoming a warm front into a deepening low over southeastern CO. By 12Z, the cold front should reach northern IL, central/southwestern MO, north-central OK, then into the low, which will have sagged into the northern TX Panhandle. ...IA/MO/northeastern KS and vicinity... A swath of decaying convection and associated cloud shield are ongoing from Lower MI to IA and parts of southeastern NE and northwestern MO. This plume of clouds/precip should continue to shift east-northeastward and erode through the day, but leave behind an outflow/differential-heating boundary that, southwest of the synoptic warm front, should act as the primary convective influence ahead of the cold front. Convergence near these boundaries, and strong heating in the richly moist warm sector between, will support scattered afternoon thunderstorms. This will include the potential for a few supercells with tornado and large-hail threats, whether relatively discrete early in the convective cycle, or embedded in subsequent quasi-linear evolution. That upscale convective organization also will maximize severe-wind potential from late afternoon into early evening, before activity encounters a more-stable, nocturnally cooling airmass farther east near the warm-frontal thermal gradient. In the preconvective warm sector, 70s F surface dewpoints should be common, as a Gulf-origin airmass blends with areas of evapotranspirative moisture contribution. Though mid/upper-level lapse rates will be modest, strong low-level destabilization will combine with a deep troposphere to contribute to MLCAPE in the 2000-3000 J/kg range. Effective-shear magnitudes will have a large range -- roughly 35-55 kt based strongly on boundary effects upon near-surface winds. Boundary-layer shear/hodographs will be greatest near the warm front and along any mesoscale boundaries between the fronts, locally maximizing supercell organization in low levels. ...Central/southern High Plains... Widely scattered to scattered thunderstorms are forecast to develop this afternoon over western portions of this area -- initially over relatively high elevations of southeast WY, east-central/ southeastern CO and northeastern NM, where diurnal heating will preferentially erode MLCINH. This activity should move generally eastward onto the adjoining High Plains, offering sporadic severe gusts and hail. The greatest concentration of convection (and associated severe potential) still appears most probable over southeastern CO, growing upscale as a complex and moving into parts of southwestern KS this evening. Vertical shear will be most favorable for supercells north of the front, where a substantial easterly component of boundary-layer flow will contribute to enhanced low-level shear, greater storm-relative low-level winds, upslope lift, and moist advection (to offset mixing-related moisture loss somewhat). The northern lobe of the (marginal) outlook area will be under the greatest mid/upper-level flow and strongest deep shear, but also will have weaker low-level moisture/theta-e and less buoyancy than farther south, with similar mid/upper-level lapse rates under a monsoonal plume as closer to the subtropical ridge. In the Arkansas River Valley region, activity moving into 50s to low 60s F surface dewpoints, with a strongly heated boundary layer, will encounter peak diurnal MLCAPE of 500-1500 J/kg across southeastern CO, and 1000-2000 J/kg into southwestern KS, amidst 45-55 kt effective-shear magnitudes, and long/nearly straight low-level hodographs favoring large hail with any discrete supercells. However, a well-mixed subcloud layer should support severe outflow and aggregation of outflows, leading to upscale clustering for a few hours before activity encounters too much CINH to remain severe over southern/central KS. Farther south, along and south of the front, deep-layer flow and shear will be weaker, as will buoyancy (due to drier, deeper mixed layers), but convection still may pose a threat for isolated severe downbursts. ..Edwards/Kerr.. 07/02/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Tue Jul 02 2024 Valid 021300Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHERN IOWA...NORTHERN MISSOURI...NORTHEASTERN KANSAS...AND EXTREME SOUTHEASTERN NEBRASKA... ...SUMMARY... Damaging thunderstorm winds, a few tornadoes, and large hail are most likely this afternoon and early evening over southern Iowa, northern Missouri, and northeastern Kansas. ...Synopsis... Broadly cyclonic flow in mid/upper levels will persist from the Pacific Northwest across the central/northern Rockies to the Upper Great Lakes. Within that, a series of shortwave troughs were apparent, the most prominent over the CONUS being located initially across WY and northeastern UT. This perturbation should move eastward to eastern SD and central NE by 00Z, cross the upper Mississippi Valley overnight, and reach parts of WI and the Upper Peninsula of MI by the end of the period. As that occurs, a persistent subtropical high over the Arklatex region will shift eastward over the Delta region, but with attached ridging expanding back across central and west TX to near ELP. Another attached ridge will shift eastward across the Ohio Valley and Lower Great Lakes. At the surface, 11Z analysis showed a surface low near HLC, with cold front southwestward across extreme southeastern CO and northeastern/north-central NM. A warm front arched from the low across southeastern NE, then southward near the KS/MO and AR/OK borders. The warm front should move northeastward to the mid Mississippi Valley today while the low moves northeastward and weakens. Meanwhile, by 00Z, the cold front should reach western IA, northeastern through south-central KS, and the northern TX Panhandle. becoming a warm front into a deepening low over southeastern CO. By 12Z, the cold front should reach northern IL, central/southwestern MO, north-central OK, then into the low, which will have sagged into the northern TX Panhandle. ...IA/MO/northeastern KS and vicinity... A swath of decaying convection and associated cloud shield are ongoing from Lower MI to IA and parts of southeastern NE and northwestern MO. This plume of clouds/precip should continue to shift east-northeastward and erode through the day, but leave behind an outflow/differential-heating boundary that, southwest of the synoptic warm front, should act as the primary convective influence ahead of the cold front. Convergence near these boundaries, and strong heating in the richly moist warm sector between, will support scattered afternoon thunderstorms. This will include the potential for a few supercells with tornado and large-hail threats, whether relatively discrete early in the convective cycle, or embedded in subsequent quasi-linear evolution. That upscale convective organization also will maximize severe-wind potential from late afternoon into early evening, before activity encounters a more-stable, nocturnally cooling airmass farther east near the warm-frontal thermal gradient. In the preconvective warm sector, 70s F surface dewpoints should be common, as a Gulf-origin airmass blends with areas of evapotranspirative moisture contribution. Though mid/upper-level lapse rates will be modest, strong low-level destabilization will combine with a deep troposphere to contribute to MLCAPE in the 2000-3000 J/kg range. Effective-shear magnitudes will have a large range -- roughly 35-55 kt based strongly on boundary effects upon near-surface winds. Boundary-layer shear/hodographs will be greatest near the warm front and along any mesoscale boundaries between the fronts, locally maximizing supercell organization in low levels. ...Central/southern High Plains... Widely scattered to scattered thunderstorms are forecast to develop this afternoon over western portions of this area -- initially over relatively high elevations of southeast WY, east-central/ southeastern CO and northeastern NM, where diurnal heating will preferentially erode MLCINH. This activity should move generally eastward onto the adjoining High Plains, offering sporadic severe gusts and hail. The greatest concentration of convection (and associated severe potential) still appears most probable over southeastern CO, growing upscale as a complex and moving into parts of southwestern KS this evening. Vertical shear will be most favorable for supercells north of the front, where a substantial easterly component of boundary-layer flow will contribute to enhanced low-level shear, greater storm-relative low-level winds, upslope lift, and moist advection (to offset mixing-related moisture loss somewhat). The northern lobe of the (marginal) outlook area will be under the greatest mid/upper-level flow and strongest deep shear, but also will have weaker low-level moisture/theta-e and less buoyancy than farther south, with similar mid/upper-level lapse rates under a monsoonal plume as closer to the subtropical ridge. In the Arkansas River Valley region, activity moving into 50s to low 60s F surface dewpoints, with a strongly heated boundary layer, will encounter peak diurnal MLCAPE of 500-1500 J/kg across southeastern CO, and 1000-2000 J/kg into southwestern KS, amidst 45-55 kt effective-shear magnitudes, and long/nearly straight low-level hodographs favoring large hail with any discrete supercells. However, a well-mixed subcloud layer should support severe outflow and aggregation of outflows, leading to upscale clustering for a few hours before activity encounters too much CINH to remain severe over southern/central KS. Farther south, along and south of the front, deep-layer flow and shear will be weaker, as will buoyancy (due to drier, deeper mixed layers), but convection still may pose a threat for isolated severe downbursts. ..Edwards/Kerr.. 07/02/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Tue Jul 02 2024 Valid 021300Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHERN IOWA...NORTHERN MISSOURI...NORTHEASTERN KANSAS...AND EXTREME SOUTHEASTERN NEBRASKA... ...SUMMARY... Damaging thunderstorm winds, a few tornadoes, and large hail are most likely this afternoon and early evening over southern Iowa, northern Missouri, and northeastern Kansas. ...Synopsis... Broadly cyclonic flow in mid/upper levels will persist from the Pacific Northwest across the central/northern Rockies to the Upper Great Lakes. Within that, a series of shortwave troughs were apparent, the most prominent over the CONUS being located initially across WY and northeastern UT. This perturbation should move eastward to eastern SD and central NE by 00Z, cross the upper Mississippi Valley overnight, and reach parts of WI and the Upper Peninsula of MI by the end of the period. As that occurs, a persistent subtropical high over the Arklatex region will shift eastward over the Delta region, but with attached ridging expanding back across central and west TX to near ELP. Another attached ridge will shift eastward across the Ohio Valley and Lower Great Lakes. At the surface, 11Z analysis showed a surface low near HLC, with cold front southwestward across extreme southeastern CO and northeastern/north-central NM. A warm front arched from the low across southeastern NE, then southward near the KS/MO and AR/OK borders. The warm front should move northeastward to the mid Mississippi Valley today while the low moves northeastward and weakens. Meanwhile, by 00Z, the cold front should reach western IA, northeastern through south-central KS, and the northern TX Panhandle. becoming a warm front into a deepening low over southeastern CO. By 12Z, the cold front should reach northern IL, central/southwestern MO, north-central OK, then into the low, which will have sagged into the northern TX Panhandle. ...IA/MO/northeastern KS and vicinity... A swath of decaying convection and associated cloud shield are ongoing from Lower MI to IA and parts of southeastern NE and northwestern MO. This plume of clouds/precip should continue to shift east-northeastward and erode through the day, but leave behind an outflow/differential-heating boundary that, southwest of the synoptic warm front, should act as the primary convective influence ahead of the cold front. Convergence near these boundaries, and strong heating in the richly moist warm sector between, will support scattered afternoon thunderstorms. This will include the potential for a few supercells with tornado and large-hail threats, whether relatively discrete early in the convective cycle, or embedded in subsequent quasi-linear evolution. That upscale convective organization also will maximize severe-wind potential from late afternoon into early evening, before activity encounters a more-stable, nocturnally cooling airmass farther east near the warm-frontal thermal gradient. In the preconvective warm sector, 70s F surface dewpoints should be common, as a Gulf-origin airmass blends with areas of evapotranspirative moisture contribution. Though mid/upper-level lapse rates will be modest, strong low-level destabilization will combine with a deep troposphere to contribute to MLCAPE in the 2000-3000 J/kg range. Effective-shear magnitudes will have a large range -- roughly 35-55 kt based strongly on boundary effects upon near-surface winds. Boundary-layer shear/hodographs will be greatest near the warm front and along any mesoscale boundaries between the fronts, locally maximizing supercell organization in low levels. ...Central/southern High Plains... Widely scattered to scattered thunderstorms are forecast to develop this afternoon over western portions of this area -- initially over relatively high elevations of southeast WY, east-central/ southeastern CO and northeastern NM, where diurnal heating will preferentially erode MLCINH. This activity should move generally eastward onto the adjoining High Plains, offering sporadic severe gusts and hail. The greatest concentration of convection (and associated severe potential) still appears most probable over southeastern CO, growing upscale as a complex and moving into parts of southwestern KS this evening. Vertical shear will be most favorable for supercells north of the front, where a substantial easterly component of boundary-layer flow will contribute to enhanced low-level shear, greater storm-relative low-level winds, upslope lift, and moist advection (to offset mixing-related moisture loss somewhat). The northern lobe of the (marginal) outlook area will be under the greatest mid/upper-level flow and strongest deep shear, but also will have weaker low-level moisture/theta-e and less buoyancy than farther south, with similar mid/upper-level lapse rates under a monsoonal plume as closer to the subtropical ridge. In the Arkansas River Valley region, activity moving into 50s to low 60s F surface dewpoints, with a strongly heated boundary layer, will encounter peak diurnal MLCAPE of 500-1500 J/kg across southeastern CO, and 1000-2000 J/kg into southwestern KS, amidst 45-55 kt effective-shear magnitudes, and long/nearly straight low-level hodographs favoring large hail with any discrete supercells. However, a well-mixed subcloud layer should support severe outflow and aggregation of outflows, leading to upscale clustering for a few hours before activity encounters too much CINH to remain severe over southern/central KS. Farther south, along and south of the front, deep-layer flow and shear will be weaker, as will buoyancy (due to drier, deeper mixed layers), but convection still may pose a threat for isolated severe downbursts. ..Edwards/Kerr.. 07/02/2024 Read more

000
ABPZ20 KNHC 021153
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Tue Jul 2 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Offshore of Southern Mexico:
Satellite data indicate a broad area of low pressure is forming a
few hundred miles south of the coast of southern Mexico. The system
is producing a large area of disorganized shower and thunderstorm
activity. Environmental conditions could support some gradual
development of this system, and a tropical depression could form
during the next few days while it moves northward to northwestward
at 10 to 15 mph.
* Formation chance through 48 hours...low....30 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Reinhart

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0402 AM CDT Tue Jul 02 2024 Valid 051200Z - 101200Z ...DISCUSSION... ...Day 4/Friday Midwest and Ohio Valley... While modest predictability continues to preclude a 15+ percent severe risk at this juncture, it seems probable that severe thunderstorm potential will be focused within a moist and unstable air mass near and ahead of an east/southeastward-moving cold front. This is most probable across the Ohio Valley and other parts of the Midwest/Lake Erie vicinity including states such as Kentucky and Ohio. Damaging winds are expected to be the most common severe hazard. ...Day 5/Saturday... Severe-thunderstorm potential should spread eastward into the Northeast/Mid-Atlantic States in relation to the low-amplitude shortwave trough and eastward-moving cold front. Other at least isolated severe storms may occur across the northern Plains/Upper Midwest, generally related to an amplifying shortwave trough and weak front. Risk magnitude uncertainties preclude 15+ percent severe risk areas. ...Days 6-8 Sunday-Tuesday... Daily severe-weather potential can be expected, although specific predictability is limited into this time frame, as is typical for this season. Early estimates are that severe-storm potential could increase across the south-central Plains to Upper Midwest on Day 6/Sunday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0402 AM CDT Tue Jul 02 2024 Valid 051200Z - 101200Z ...DISCUSSION... ...Day 4/Friday Midwest and Ohio Valley... While modest predictability continues to preclude a 15+ percent severe risk at this juncture, it seems probable that severe thunderstorm potential will be focused within a moist and unstable air mass near and ahead of an east/southeastward-moving cold front. This is most probable across the Ohio Valley and other parts of the Midwest/Lake Erie vicinity including states such as Kentucky and Ohio. Damaging winds are expected to be the most common severe hazard. ...Day 5/Saturday... Severe-thunderstorm potential should spread eastward into the Northeast/Mid-Atlantic States in relation to the low-amplitude shortwave trough and eastward-moving cold front. Other at least isolated severe storms may occur across the northern Plains/Upper Midwest, generally related to an amplifying shortwave trough and weak front. Risk magnitude uncertainties preclude 15+ percent severe risk areas. ...Days 6-8 Sunday-Tuesday... Daily severe-weather potential can be expected, although specific predictability is limited into this time frame, as is typical for this season. Early estimates are that severe-storm potential could increase across the south-central Plains to Upper Midwest on Day 6/Sunday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0402 AM CDT Tue Jul 02 2024 Valid 051200Z - 101200Z ...DISCUSSION... ...Day 4/Friday Midwest and Ohio Valley... While modest predictability continues to preclude a 15+ percent severe risk at this juncture, it seems probable that severe thunderstorm potential will be focused within a moist and unstable air mass near and ahead of an east/southeastward-moving cold front. This is most probable across the Ohio Valley and other parts of the Midwest/Lake Erie vicinity including states such as Kentucky and Ohio. Damaging winds are expected to be the most common severe hazard. ...Day 5/Saturday... Severe-thunderstorm potential should spread eastward into the Northeast/Mid-Atlantic States in relation to the low-amplitude shortwave trough and eastward-moving cold front. Other at least isolated severe storms may occur across the northern Plains/Upper Midwest, generally related to an amplifying shortwave trough and weak front. Risk magnitude uncertainties preclude 15+ percent severe risk areas. ...Days 6-8 Sunday-Tuesday... Daily severe-weather potential can be expected, although specific predictability is limited into this time frame, as is typical for this season. Early estimates are that severe-storm potential could increase across the south-central Plains to Upper Midwest on Day 6/Sunday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0402 AM CDT Tue Jul 02 2024 Valid 051200Z - 101200Z ...DISCUSSION... ...Day 4/Friday Midwest and Ohio Valley... While modest predictability continues to preclude a 15+ percent severe risk at this juncture, it seems probable that severe thunderstorm potential will be focused within a moist and unstable air mass near and ahead of an east/southeastward-moving cold front. This is most probable across the Ohio Valley and other parts of the Midwest/Lake Erie vicinity including states such as Kentucky and Ohio. Damaging winds are expected to be the most common severe hazard. ...Day 5/Saturday... Severe-thunderstorm potential should spread eastward into the Northeast/Mid-Atlantic States in relation to the low-amplitude shortwave trough and eastward-moving cold front. Other at least isolated severe storms may occur across the northern Plains/Upper Midwest, generally related to an amplifying shortwave trough and weak front. Risk magnitude uncertainties preclude 15+ percent severe risk areas. ...Days 6-8 Sunday-Tuesday... Daily severe-weather potential can be expected, although specific predictability is limited into this time frame, as is typical for this season. Early estimates are that severe-storm potential could increase across the south-central Plains to Upper Midwest on Day 6/Sunday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0402 AM CDT Tue Jul 02 2024 Valid 051200Z - 101200Z ...DISCUSSION... ...Day 4/Friday Midwest and Ohio Valley... While modest predictability continues to preclude a 15+ percent severe risk at this juncture, it seems probable that severe thunderstorm potential will be focused within a moist and unstable air mass near and ahead of an east/southeastward-moving cold front. This is most probable across the Ohio Valley and other parts of the Midwest/Lake Erie vicinity including states such as Kentucky and Ohio. Damaging winds are expected to be the most common severe hazard. ...Day 5/Saturday... Severe-thunderstorm potential should spread eastward into the Northeast/Mid-Atlantic States in relation to the low-amplitude shortwave trough and eastward-moving cold front. Other at least isolated severe storms may occur across the northern Plains/Upper Midwest, generally related to an amplifying shortwave trough and weak front. Risk magnitude uncertainties preclude 15+ percent severe risk areas. ...Days 6-8 Sunday-Tuesday... Daily severe-weather potential can be expected, although specific predictability is limited into this time frame, as is typical for this season. Early estimates are that severe-storm potential could increase across the south-central Plains to Upper Midwest on Day 6/Sunday. Read more