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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Jun 29 2024 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST...AND OVER THE RATON MESA AND NEARBY SOUTH-CENTRAL HIGH PLAINS... ...SUMMARY... Damaging thunderstorm gusts and a few tornadoes are possible today over parts of the Lower Great Lakes to upper Ohio Valley, while severe gusts also may be focused this afternoon and evening over the Raton Mesa and nearby south-central High Plains. ...Synopsis... Broadly, the upper-air pattern will be characterized by a synoptic trough moving ashore from the Pacific and over the West Coast States, the downstream ridge moving slowly out of the northern/ central Rockies onto the adjoining High Plains, and troughing over the Great Lakes and vicinity. Meanwhile, strong subtropical ridging will prevail across the Southeast, southern Plains, and NM. A northern-stream shortwave trough -- evident in moisture-channel imagery over northeastern MN -- will eject east-northeastward today and weaken, while effectively replaced by an upstream perturbation now over portions of ND/MB. The resulting shortwave trough should proceed eastward across the Upper Great Lakes to Lake Huron and adjoining parts of ON by 12Z tomorrow. To its south and southeast, a belt of strong, cyclonically curved flow will cover the mid/upper Ohio Valley and Northeast, with minor embedded perturbations (some convectively generated upstream from prior/overnight activity). At the surface, the 11Z analysis showed a low over central Lake Superior, with cold front across central Upper MI, southern WI, southern IA, central KS, and north-central NM. By 00Z, the cold front should move to northern IN, central IL, southern MO, northern OK, the northern TX Panhandle, and northeastern/central NM. By 12Z, the front should extend from western parts of NY/PA across KY, the MO Bootheel area, and northern AR, becoming quasistationary over central/western OK, the central TX Panhandle, and east-central NM. A prefrontal surface trough should shift eastward from the St. Lawrence Valley/Lower Great Lakes across the northern Appalachians and northern Mid-Atlantic States through the period. ...Northeast/Ohio Valley/Great Lakes... Scattered thunderstorms are expected to form episodically from midday through afternoon -- predominantly ahead of the surface cold front. Frontal convection over parts of Lower MI also is possible this afternoon, with isolated severe hail/gusts. The main severe threat, however should be over parts of the Lower Great Lakes/upper Ohio Valley into nearly Appalachians. With weak capping, activity may form on a variety of foci, near the main surface trough, outflow boundaries from morning clouds/precip, and over areas of differential heating and orographic lift. Activity should organize into one or more lines with embedded supercells and bowing/LEWP segments possible. The main threat will be damaging to severe gusts in and near the 15%/"slight" area, though any supercells or embedded QLCS vortices also will pose a tornado threat. Despite weak mid/upper-level lapse rates over most of this region, warm-sector moisture will be characterized by mid 60s to lower 70s F surface dewpoints. This will combine with pockets of sustained surface heating to yield MLCAPE in the 1000-2000 J/kg range. Veering and strengthening of winds with height in low levels should yield enlarged hodographs below 3 km, with effective SRH in the 150-250 J/kg range overlapping areas of favorable heating in some parts of the upper Ohio Valley area into central PA. Little speed shear is apparent from the top of the boundary layer into the mid/upper levels, however, limiting deep shear, and storm structure may become messy rather quickly. Overall, convection should weaken as it approaches the Atlantic Coast this evening, and the foregoing inflow layer becomes more stable. ...South-central Rockies/High Plains... Isolated to scattered thunderstorms are forecast to develop this afternoon over higher terrain from the southern Front Range area across the Sangre de Cristos and Raton Mesa. This will occur as strong heating of higher terrain preferentially erodes MLCINH, in the presence of post-frontal upslope flow in low levels, and related moisture advection to at least partially offset moisture loss due to mixing. The easterly component also should aid storm-relative boundary-layer flow and deep shear for activity propagating eastward off the elevated terrain, with a mix of multicells and transient supercells possible. Despite modest low/middle-level wind speeds, forecast soundings reasonably depict enough veering with height to yield 35-45-kt effective-shear magnitudes, amidst 500-1500 J/kg MLCAPE and steep boundary-layer lapse rates. Some of the resulting convection may coalesce into a complex of thunderstorms with a cold pool, in turn driving eastward-directed forward propagation near the post-frontal moist axis and across parts of southeastern CO, northeastern NM, the adjacent Panhandles, and or southwestern KS, with a relatively focused threat of severe gusts. ...Ozarks/south-central Plains... Ongoing, isolated to widely scattered convection over parts of KS/MO should weaken/dissipate through the remainder of the morning, but may leave behind enough cloud material and (especially in MO) outflow to augment frontal baroclinicity for afternoon convective initiation. Widely scattered to scattered thunderstorms should develop on and near the front this afternoon from northern OK and extreme southern KS to the Ozarks, in a regime of MLCINH substantially removed by modest low-level convergence and strong diurnal/prefrontal heating. Deep mixing south of the front should reduce surface dewpoints and buoyancy in the warm sector, but adequate moisture (with 60s to low 70s F surface dewpoints) should linger in a narrow post-frontal corridor supporting 2000-3000 J/kg MLCAPE. The net result should be high-based, multicell thunderstorms in mostly weak deep shear, with pulse severe in the form of gusts and hail. A conditional risk exists for locally significant (65+ kt) gusts, given the favorably deep subcloud mixed layer with large DCAPE. However, mesoscale foci for denser coverage of such a threat still appear too nebulous for a 15% unconditional gust outlook within the broader marginal area. ..Edwards/Kerr.. 06/29/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Jun 29 2024 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST...AND OVER THE RATON MESA AND NEARBY SOUTH-CENTRAL HIGH PLAINS... ...SUMMARY... Damaging thunderstorm gusts and a few tornadoes are possible today over parts of the Lower Great Lakes to upper Ohio Valley, while severe gusts also may be focused this afternoon and evening over the Raton Mesa and nearby south-central High Plains. ...Synopsis... Broadly, the upper-air pattern will be characterized by a synoptic trough moving ashore from the Pacific and over the West Coast States, the downstream ridge moving slowly out of the northern/ central Rockies onto the adjoining High Plains, and troughing over the Great Lakes and vicinity. Meanwhile, strong subtropical ridging will prevail across the Southeast, southern Plains, and NM. A northern-stream shortwave trough -- evident in moisture-channel imagery over northeastern MN -- will eject east-northeastward today and weaken, while effectively replaced by an upstream perturbation now over portions of ND/MB. The resulting shortwave trough should proceed eastward across the Upper Great Lakes to Lake Huron and adjoining parts of ON by 12Z tomorrow. To its south and southeast, a belt of strong, cyclonically curved flow will cover the mid/upper Ohio Valley and Northeast, with minor embedded perturbations (some convectively generated upstream from prior/overnight activity). At the surface, the 11Z analysis showed a low over central Lake Superior, with cold front across central Upper MI, southern WI, southern IA, central KS, and north-central NM. By 00Z, the cold front should move to northern IN, central IL, southern MO, northern OK, the northern TX Panhandle, and northeastern/central NM. By 12Z, the front should extend from western parts of NY/PA across KY, the MO Bootheel area, and northern AR, becoming quasistationary over central/western OK, the central TX Panhandle, and east-central NM. A prefrontal surface trough should shift eastward from the St. Lawrence Valley/Lower Great Lakes across the northern Appalachians and northern Mid-Atlantic States through the period. ...Northeast/Ohio Valley/Great Lakes... Scattered thunderstorms are expected to form episodically from midday through afternoon -- predominantly ahead of the surface cold front. Frontal convection over parts of Lower MI also is possible this afternoon, with isolated severe hail/gusts. The main severe threat, however should be over parts of the Lower Great Lakes/upper Ohio Valley into nearly Appalachians. With weak capping, activity may form on a variety of foci, near the main surface trough, outflow boundaries from morning clouds/precip, and over areas of differential heating and orographic lift. Activity should organize into one or more lines with embedded supercells and bowing/LEWP segments possible. The main threat will be damaging to severe gusts in and near the 15%/"slight" area, though any supercells or embedded QLCS vortices also will pose a tornado threat. Despite weak mid/upper-level lapse rates over most of this region, warm-sector moisture will be characterized by mid 60s to lower 70s F surface dewpoints. This will combine with pockets of sustained surface heating to yield MLCAPE in the 1000-2000 J/kg range. Veering and strengthening of winds with height in low levels should yield enlarged hodographs below 3 km, with effective SRH in the 150-250 J/kg range overlapping areas of favorable heating in some parts of the upper Ohio Valley area into central PA. Little speed shear is apparent from the top of the boundary layer into the mid/upper levels, however, limiting deep shear, and storm structure may become messy rather quickly. Overall, convection should weaken as it approaches the Atlantic Coast this evening, and the foregoing inflow layer becomes more stable. ...South-central Rockies/High Plains... Isolated to scattered thunderstorms are forecast to develop this afternoon over higher terrain from the southern Front Range area across the Sangre de Cristos and Raton Mesa. This will occur as strong heating of higher terrain preferentially erodes MLCINH, in the presence of post-frontal upslope flow in low levels, and related moisture advection to at least partially offset moisture loss due to mixing. The easterly component also should aid storm-relative boundary-layer flow and deep shear for activity propagating eastward off the elevated terrain, with a mix of multicells and transient supercells possible. Despite modest low/middle-level wind speeds, forecast soundings reasonably depict enough veering with height to yield 35-45-kt effective-shear magnitudes, amidst 500-1500 J/kg MLCAPE and steep boundary-layer lapse rates. Some of the resulting convection may coalesce into a complex of thunderstorms with a cold pool, in turn driving eastward-directed forward propagation near the post-frontal moist axis and across parts of southeastern CO, northeastern NM, the adjacent Panhandles, and or southwestern KS, with a relatively focused threat of severe gusts. ...Ozarks/south-central Plains... Ongoing, isolated to widely scattered convection over parts of KS/MO should weaken/dissipate through the remainder of the morning, but may leave behind enough cloud material and (especially in MO) outflow to augment frontal baroclinicity for afternoon convective initiation. Widely scattered to scattered thunderstorms should develop on and near the front this afternoon from northern OK and extreme southern KS to the Ozarks, in a regime of MLCINH substantially removed by modest low-level convergence and strong diurnal/prefrontal heating. Deep mixing south of the front should reduce surface dewpoints and buoyancy in the warm sector, but adequate moisture (with 60s to low 70s F surface dewpoints) should linger in a narrow post-frontal corridor supporting 2000-3000 J/kg MLCAPE. The net result should be high-based, multicell thunderstorms in mostly weak deep shear, with pulse severe in the form of gusts and hail. A conditional risk exists for locally significant (65+ kt) gusts, given the favorably deep subcloud mixed layer with large DCAPE. However, mesoscale foci for denser coverage of such a threat still appear too nebulous for a 15% unconditional gust outlook within the broader marginal area. ..Edwards/Kerr.. 06/29/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Jun 29 2024 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST...AND OVER THE RATON MESA AND NEARBY SOUTH-CENTRAL HIGH PLAINS... ...SUMMARY... Damaging thunderstorm gusts and a few tornadoes are possible today over parts of the Lower Great Lakes to upper Ohio Valley, while severe gusts also may be focused this afternoon and evening over the Raton Mesa and nearby south-central High Plains. ...Synopsis... Broadly, the upper-air pattern will be characterized by a synoptic trough moving ashore from the Pacific and over the West Coast States, the downstream ridge moving slowly out of the northern/ central Rockies onto the adjoining High Plains, and troughing over the Great Lakes and vicinity. Meanwhile, strong subtropical ridging will prevail across the Southeast, southern Plains, and NM. A northern-stream shortwave trough -- evident in moisture-channel imagery over northeastern MN -- will eject east-northeastward today and weaken, while effectively replaced by an upstream perturbation now over portions of ND/MB. The resulting shortwave trough should proceed eastward across the Upper Great Lakes to Lake Huron and adjoining parts of ON by 12Z tomorrow. To its south and southeast, a belt of strong, cyclonically curved flow will cover the mid/upper Ohio Valley and Northeast, with minor embedded perturbations (some convectively generated upstream from prior/overnight activity). At the surface, the 11Z analysis showed a low over central Lake Superior, with cold front across central Upper MI, southern WI, southern IA, central KS, and north-central NM. By 00Z, the cold front should move to northern IN, central IL, southern MO, northern OK, the northern TX Panhandle, and northeastern/central NM. By 12Z, the front should extend from western parts of NY/PA across KY, the MO Bootheel area, and northern AR, becoming quasistationary over central/western OK, the central TX Panhandle, and east-central NM. A prefrontal surface trough should shift eastward from the St. Lawrence Valley/Lower Great Lakes across the northern Appalachians and northern Mid-Atlantic States through the period. ...Northeast/Ohio Valley/Great Lakes... Scattered thunderstorms are expected to form episodically from midday through afternoon -- predominantly ahead of the surface cold front. Frontal convection over parts of Lower MI also is possible this afternoon, with isolated severe hail/gusts. The main severe threat, however should be over parts of the Lower Great Lakes/upper Ohio Valley into nearly Appalachians. With weak capping, activity may form on a variety of foci, near the main surface trough, outflow boundaries from morning clouds/precip, and over areas of differential heating and orographic lift. Activity should organize into one or more lines with embedded supercells and bowing/LEWP segments possible. The main threat will be damaging to severe gusts in and near the 15%/"slight" area, though any supercells or embedded QLCS vortices also will pose a tornado threat. Despite weak mid/upper-level lapse rates over most of this region, warm-sector moisture will be characterized by mid 60s to lower 70s F surface dewpoints. This will combine with pockets of sustained surface heating to yield MLCAPE in the 1000-2000 J/kg range. Veering and strengthening of winds with height in low levels should yield enlarged hodographs below 3 km, with effective SRH in the 150-250 J/kg range overlapping areas of favorable heating in some parts of the upper Ohio Valley area into central PA. Little speed shear is apparent from the top of the boundary layer into the mid/upper levels, however, limiting deep shear, and storm structure may become messy rather quickly. Overall, convection should weaken as it approaches the Atlantic Coast this evening, and the foregoing inflow layer becomes more stable. ...South-central Rockies/High Plains... Isolated to scattered thunderstorms are forecast to develop this afternoon over higher terrain from the southern Front Range area across the Sangre de Cristos and Raton Mesa. This will occur as strong heating of higher terrain preferentially erodes MLCINH, in the presence of post-frontal upslope flow in low levels, and related moisture advection to at least partially offset moisture loss due to mixing. The easterly component also should aid storm-relative boundary-layer flow and deep shear for activity propagating eastward off the elevated terrain, with a mix of multicells and transient supercells possible. Despite modest low/middle-level wind speeds, forecast soundings reasonably depict enough veering with height to yield 35-45-kt effective-shear magnitudes, amidst 500-1500 J/kg MLCAPE and steep boundary-layer lapse rates. Some of the resulting convection may coalesce into a complex of thunderstorms with a cold pool, in turn driving eastward-directed forward propagation near the post-frontal moist axis and across parts of southeastern CO, northeastern NM, the adjacent Panhandles, and or southwestern KS, with a relatively focused threat of severe gusts. ...Ozarks/south-central Plains... Ongoing, isolated to widely scattered convection over parts of KS/MO should weaken/dissipate through the remainder of the morning, but may leave behind enough cloud material and (especially in MO) outflow to augment frontal baroclinicity for afternoon convective initiation. Widely scattered to scattered thunderstorms should develop on and near the front this afternoon from northern OK and extreme southern KS to the Ozarks, in a regime of MLCINH substantially removed by modest low-level convergence and strong diurnal/prefrontal heating. Deep mixing south of the front should reduce surface dewpoints and buoyancy in the warm sector, but adequate moisture (with 60s to low 70s F surface dewpoints) should linger in a narrow post-frontal corridor supporting 2000-3000 J/kg MLCAPE. The net result should be high-based, multicell thunderstorms in mostly weak deep shear, with pulse severe in the form of gusts and hail. A conditional risk exists for locally significant (65+ kt) gusts, given the favorably deep subcloud mixed layer with large DCAPE. However, mesoscale foci for denser coverage of such a threat still appear too nebulous for a 15% unconditional gust outlook within the broader marginal area. ..Edwards/Kerr.. 06/29/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Jun 29 2024 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST...AND OVER THE RATON MESA AND NEARBY SOUTH-CENTRAL HIGH PLAINS... ...SUMMARY... Damaging thunderstorm gusts and a few tornadoes are possible today over parts of the Lower Great Lakes to upper Ohio Valley, while severe gusts also may be focused this afternoon and evening over the Raton Mesa and nearby south-central High Plains. ...Synopsis... Broadly, the upper-air pattern will be characterized by a synoptic trough moving ashore from the Pacific and over the West Coast States, the downstream ridge moving slowly out of the northern/ central Rockies onto the adjoining High Plains, and troughing over the Great Lakes and vicinity. Meanwhile, strong subtropical ridging will prevail across the Southeast, southern Plains, and NM. A northern-stream shortwave trough -- evident in moisture-channel imagery over northeastern MN -- will eject east-northeastward today and weaken, while effectively replaced by an upstream perturbation now over portions of ND/MB. The resulting shortwave trough should proceed eastward across the Upper Great Lakes to Lake Huron and adjoining parts of ON by 12Z tomorrow. To its south and southeast, a belt of strong, cyclonically curved flow will cover the mid/upper Ohio Valley and Northeast, with minor embedded perturbations (some convectively generated upstream from prior/overnight activity). At the surface, the 11Z analysis showed a low over central Lake Superior, with cold front across central Upper MI, southern WI, southern IA, central KS, and north-central NM. By 00Z, the cold front should move to northern IN, central IL, southern MO, northern OK, the northern TX Panhandle, and northeastern/central NM. By 12Z, the front should extend from western parts of NY/PA across KY, the MO Bootheel area, and northern AR, becoming quasistationary over central/western OK, the central TX Panhandle, and east-central NM. A prefrontal surface trough should shift eastward from the St. Lawrence Valley/Lower Great Lakes across the northern Appalachians and northern Mid-Atlantic States through the period. ...Northeast/Ohio Valley/Great Lakes... Scattered thunderstorms are expected to form episodically from midday through afternoon -- predominantly ahead of the surface cold front. Frontal convection over parts of Lower MI also is possible this afternoon, with isolated severe hail/gusts. The main severe threat, however should be over parts of the Lower Great Lakes/upper Ohio Valley into nearly Appalachians. With weak capping, activity may form on a variety of foci, near the main surface trough, outflow boundaries from morning clouds/precip, and over areas of differential heating and orographic lift. Activity should organize into one or more lines with embedded supercells and bowing/LEWP segments possible. The main threat will be damaging to severe gusts in and near the 15%/"slight" area, though any supercells or embedded QLCS vortices also will pose a tornado threat. Despite weak mid/upper-level lapse rates over most of this region, warm-sector moisture will be characterized by mid 60s to lower 70s F surface dewpoints. This will combine with pockets of sustained surface heating to yield MLCAPE in the 1000-2000 J/kg range. Veering and strengthening of winds with height in low levels should yield enlarged hodographs below 3 km, with effective SRH in the 150-250 J/kg range overlapping areas of favorable heating in some parts of the upper Ohio Valley area into central PA. Little speed shear is apparent from the top of the boundary layer into the mid/upper levels, however, limiting deep shear, and storm structure may become messy rather quickly. Overall, convection should weaken as it approaches the Atlantic Coast this evening, and the foregoing inflow layer becomes more stable. ...South-central Rockies/High Plains... Isolated to scattered thunderstorms are forecast to develop this afternoon over higher terrain from the southern Front Range area across the Sangre de Cristos and Raton Mesa. This will occur as strong heating of higher terrain preferentially erodes MLCINH, in the presence of post-frontal upslope flow in low levels, and related moisture advection to at least partially offset moisture loss due to mixing. The easterly component also should aid storm-relative boundary-layer flow and deep shear for activity propagating eastward off the elevated terrain, with a mix of multicells and transient supercells possible. Despite modest low/middle-level wind speeds, forecast soundings reasonably depict enough veering with height to yield 35-45-kt effective-shear magnitudes, amidst 500-1500 J/kg MLCAPE and steep boundary-layer lapse rates. Some of the resulting convection may coalesce into a complex of thunderstorms with a cold pool, in turn driving eastward-directed forward propagation near the post-frontal moist axis and across parts of southeastern CO, northeastern NM, the adjacent Panhandles, and or southwestern KS, with a relatively focused threat of severe gusts. ...Ozarks/south-central Plains... Ongoing, isolated to widely scattered convection over parts of KS/MO should weaken/dissipate through the remainder of the morning, but may leave behind enough cloud material and (especially in MO) outflow to augment frontal baroclinicity for afternoon convective initiation. Widely scattered to scattered thunderstorms should develop on and near the front this afternoon from northern OK and extreme southern KS to the Ozarks, in a regime of MLCINH substantially removed by modest low-level convergence and strong diurnal/prefrontal heating. Deep mixing south of the front should reduce surface dewpoints and buoyancy in the warm sector, but adequate moisture (with 60s to low 70s F surface dewpoints) should linger in a narrow post-frontal corridor supporting 2000-3000 J/kg MLCAPE. The net result should be high-based, multicell thunderstorms in mostly weak deep shear, with pulse severe in the form of gusts and hail. A conditional risk exists for locally significant (65+ kt) gusts, given the favorably deep subcloud mixed layer with large DCAPE. However, mesoscale foci for denser coverage of such a threat still appear too nebulous for a 15% unconditional gust outlook within the broader marginal area. ..Edwards/Kerr.. 06/29/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Jun 29 2024 Valid 291300Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST...AND OVER THE RATON MESA AND NEARBY SOUTH-CENTRAL HIGH PLAINS... ...SUMMARY... Damaging thunderstorm gusts and a few tornadoes are possible today over parts of the Lower Great Lakes to upper Ohio Valley, while severe gusts also may be focused this afternoon and evening over the Raton Mesa and nearby south-central High Plains. ...Synopsis... Broadly, the upper-air pattern will be characterized by a synoptic trough moving ashore from the Pacific and over the West Coast States, the downstream ridge moving slowly out of the northern/ central Rockies onto the adjoining High Plains, and troughing over the Great Lakes and vicinity. Meanwhile, strong subtropical ridging will prevail across the Southeast, southern Plains, and NM. A northern-stream shortwave trough -- evident in moisture-channel imagery over northeastern MN -- will eject east-northeastward today and weaken, while effectively replaced by an upstream perturbation now over portions of ND/MB. The resulting shortwave trough should proceed eastward across the Upper Great Lakes to Lake Huron and adjoining parts of ON by 12Z tomorrow. To its south and southeast, a belt of strong, cyclonically curved flow will cover the mid/upper Ohio Valley and Northeast, with minor embedded perturbations (some convectively generated upstream from prior/overnight activity). At the surface, the 11Z analysis showed a low over central Lake Superior, with cold front across central Upper MI, southern WI, southern IA, central KS, and north-central NM. By 00Z, the cold front should move to northern IN, central IL, southern MO, northern OK, the northern TX Panhandle, and northeastern/central NM. By 12Z, the front should extend from western parts of NY/PA across KY, the MO Bootheel area, and northern AR, becoming quasistationary over central/western OK, the central TX Panhandle, and east-central NM. A prefrontal surface trough should shift eastward from the St. Lawrence Valley/Lower Great Lakes across the northern Appalachians and northern Mid-Atlantic States through the period. ...Northeast/Ohio Valley/Great Lakes... Scattered thunderstorms are expected to form episodically from midday through afternoon -- predominantly ahead of the surface cold front. Frontal convection over parts of Lower MI also is possible this afternoon, with isolated severe hail/gusts. The main severe threat, however should be over parts of the Lower Great Lakes/upper Ohio Valley into nearly Appalachians. With weak capping, activity may form on a variety of foci, near the main surface trough, outflow boundaries from morning clouds/precip, and over areas of differential heating and orographic lift. Activity should organize into one or more lines with embedded supercells and bowing/LEWP segments possible. The main threat will be damaging to severe gusts in and near the 15%/"slight" area, though any supercells or embedded QLCS vortices also will pose a tornado threat. Despite weak mid/upper-level lapse rates over most of this region, warm-sector moisture will be characterized by mid 60s to lower 70s F surface dewpoints. This will combine with pockets of sustained surface heating to yield MLCAPE in the 1000-2000 J/kg range. Veering and strengthening of winds with height in low levels should yield enlarged hodographs below 3 km, with effective SRH in the 150-250 J/kg range overlapping areas of favorable heating in some parts of the upper Ohio Valley area into central PA. Little speed shear is apparent from the top of the boundary layer into the mid/upper levels, however, limiting deep shear, and storm structure may become messy rather quickly. Overall, convection should weaken as it approaches the Atlantic Coast this evening, and the foregoing inflow layer becomes more stable. ...South-central Rockies/High Plains... Isolated to scattered thunderstorms are forecast to develop this afternoon over higher terrain from the southern Front Range area across the Sangre de Cristos and Raton Mesa. This will occur as strong heating of higher terrain preferentially erodes MLCINH, in the presence of post-frontal upslope flow in low levels, and related moisture advection to at least partially offset moisture loss due to mixing. The easterly component also should aid storm-relative boundary-layer flow and deep shear for activity propagating eastward off the elevated terrain, with a mix of multicells and transient supercells possible. Despite modest low/middle-level wind speeds, forecast soundings reasonably depict enough veering with height to yield 35-45-kt effective-shear magnitudes, amidst 500-1500 J/kg MLCAPE and steep boundary-layer lapse rates. Some of the resulting convection may coalesce into a complex of thunderstorms with a cold pool, in turn driving eastward-directed forward propagation near the post-frontal moist axis and across parts of southeastern CO, northeastern NM, the adjacent Panhandles, and or southwestern KS, with a relatively focused threat of severe gusts. ...Ozarks/south-central Plains... Ongoing, isolated to widely scattered convection over parts of KS/MO should weaken/dissipate through the remainder of the morning, but may leave behind enough cloud material and (especially in MO) outflow to augment frontal baroclinicity for afternoon convective initiation. Widely scattered to scattered thunderstorms should develop on and near the front this afternoon from northern OK and extreme southern KS to the Ozarks, in a regime of MLCINH substantially removed by modest low-level convergence and strong diurnal/prefrontal heating. Deep mixing south of the front should reduce surface dewpoints and buoyancy in the warm sector, but adequate moisture (with 60s to low 70s F surface dewpoints) should linger in a narrow post-frontal corridor supporting 2000-3000 J/kg MLCAPE. The net result should be high-based, multicell thunderstorms in mostly weak deep shear, with pulse severe in the form of gusts and hail. A conditional risk exists for locally significant (65+ kt) gusts, given the favorably deep subcloud mixed layer with large DCAPE. However, mesoscale foci for denser coverage of such a threat still appear too nebulous for a 15% unconditional gust outlook within the broader marginal area. ..Edwards/Kerr.. 06/29/2024 Read more

000
ABPZ20 KNHC 291126
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sat Jun 29 2024

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

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Roberts

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0356 AM CDT Sat Jun 29 2024 Valid 021200Z - 071200Z ...DISCUSSION... ...Day 4/Tuesday for Corn Belt/Upper Midwest... An amplifying shortwave trough and eastward-shifting strong early summertime speed max will continue to influence the region on Tuesday. Lingering convection/outflow from Monday night will likely be a factor as far as spatial details, but it currently appears that a very moist/unstable warm sector will focus across Iowa into Tuesday afternoon and evening, ahead of a southeastward-moving cold front. Seasonally strong winds would likely support potentially intense and sustained storms including supercells. Have introduced 15 percent severe probabilities for this scenario, although spatial adjustments and refinements will be needed in future outlooks. ...Day 5/Wednesday... At least some severe-weather potential will likely exist across parts of the Midwest and Ohio Valley within the moist/unstable environment ahead of the advancing cold front. However, deep-layer shear atop the warm sector will likely be weaker as compared to prior days. Additional severe storms may occur near/north of the synoptic front across the central Plains. Limited predictability and risk-magnitude uncertainties currently precludes 15+ percent severe-weather probability delineations for these scenarios. ...Days 6-8 Thursday-Saturday... Predictability wanes into this time frame, although corridors of at least some severe storms can be expected daily, generally spanning the northern/central Plains to the Ohio Valley and potentially parts of the East. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0244 AM CDT Sat Jun 29 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible on Monday across the northern/central Plains including parts of Nebraska and South Dakota. ...Northern/central Plains and Upper Midwest... A mid/upper-level trough is expected to overspread the region with appreciable height falls, particularly by early summertime standards, as far south as Nebraska and Iowa. A surface low is forecast to deepen over the Dakotas, along a surface trough. The influences of early day convection will probably be a modulating factor and point of uncertainty spatially, but a warm front should effectively transition north-northeastward during the day, with very rich low-level moisture in its wake to the east of a weak cold front. The most surface-based severe-favorable setup may materialize across central/eastern Nebraska into Monday late afternoon/early evening, and possibly into parts of South Dakota. Seasonally strong deep-layer shear will support potentially intense supercells, with a risk for all severe hazards. Some upscale growth is possible into the evening as storms spread eastward, with a continued severe risk potentially reaching parts of Minnesota and Iowa Monday night. ...Southeast States... Some strong to locally severe storms capable of wind damage may occur Monday afternoon through early evening within a moderately unstable environment along and south of the southward-sagging front. Current thinking is that this risk is most probable across southern South Carolina and southern/eastern Georgia into northern Florida. ..Guyer.. 06/29/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0244 AM CDT Sat Jun 29 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible on Monday across the northern/central Plains including parts of Nebraska and South Dakota. ...Northern/central Plains and Upper Midwest... A mid/upper-level trough is expected to overspread the region with appreciable height falls, particularly by early summertime standards, as far south as Nebraska and Iowa. A surface low is forecast to deepen over the Dakotas, along a surface trough. The influences of early day convection will probably be a modulating factor and point of uncertainty spatially, but a warm front should effectively transition north-northeastward during the day, with very rich low-level moisture in its wake to the east of a weak cold front. The most surface-based severe-favorable setup may materialize across central/eastern Nebraska into Monday late afternoon/early evening, and possibly into parts of South Dakota. Seasonally strong deep-layer shear will support potentially intense supercells, with a risk for all severe hazards. Some upscale growth is possible into the evening as storms spread eastward, with a continued severe risk potentially reaching parts of Minnesota and Iowa Monday night. ...Southeast States... Some strong to locally severe storms capable of wind damage may occur Monday afternoon through early evening within a moderately unstable environment along and south of the southward-sagging front. Current thinking is that this risk is most probable across southern South Carolina and southern/eastern Georgia into northern Florida. ..Guyer.. 06/29/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0244 AM CDT Sat Jun 29 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible on Monday across the northern/central Plains including parts of Nebraska and South Dakota. ...Northern/central Plains and Upper Midwest... A mid/upper-level trough is expected to overspread the region with appreciable height falls, particularly by early summertime standards, as far south as Nebraska and Iowa. A surface low is forecast to deepen over the Dakotas, along a surface trough. The influences of early day convection will probably be a modulating factor and point of uncertainty spatially, but a warm front should effectively transition north-northeastward during the day, with very rich low-level moisture in its wake to the east of a weak cold front. The most surface-based severe-favorable setup may materialize across central/eastern Nebraska into Monday late afternoon/early evening, and possibly into parts of South Dakota. Seasonally strong deep-layer shear will support potentially intense supercells, with a risk for all severe hazards. Some upscale growth is possible into the evening as storms spread eastward, with a continued severe risk potentially reaching parts of Minnesota and Iowa Monday night. ...Southeast States... Some strong to locally severe storms capable of wind damage may occur Monday afternoon through early evening within a moderately unstable environment along and south of the southward-sagging front. Current thinking is that this risk is most probable across southern South Carolina and southern/eastern Georgia into northern Florida. ..Guyer.. 06/29/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0244 AM CDT Sat Jun 29 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible on Monday across the northern/central Plains including parts of Nebraska and South Dakota. ...Northern/central Plains and Upper Midwest... A mid/upper-level trough is expected to overspread the region with appreciable height falls, particularly by early summertime standards, as far south as Nebraska and Iowa. A surface low is forecast to deepen over the Dakotas, along a surface trough. The influences of early day convection will probably be a modulating factor and point of uncertainty spatially, but a warm front should effectively transition north-northeastward during the day, with very rich low-level moisture in its wake to the east of a weak cold front. The most surface-based severe-favorable setup may materialize across central/eastern Nebraska into Monday late afternoon/early evening, and possibly into parts of South Dakota. Seasonally strong deep-layer shear will support potentially intense supercells, with a risk for all severe hazards. Some upscale growth is possible into the evening as storms spread eastward, with a continued severe risk potentially reaching parts of Minnesota and Iowa Monday night. ...Southeast States... Some strong to locally severe storms capable of wind damage may occur Monday afternoon through early evening within a moderately unstable environment along and south of the southward-sagging front. Current thinking is that this risk is most probable across southern South Carolina and southern/eastern Georgia into northern Florida. ..Guyer.. 06/29/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0244 AM CDT Sat Jun 29 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible on Monday across the northern/central Plains including parts of Nebraska and South Dakota. ...Northern/central Plains and Upper Midwest... A mid/upper-level trough is expected to overspread the region with appreciable height falls, particularly by early summertime standards, as far south as Nebraska and Iowa. A surface low is forecast to deepen over the Dakotas, along a surface trough. The influences of early day convection will probably be a modulating factor and point of uncertainty spatially, but a warm front should effectively transition north-northeastward during the day, with very rich low-level moisture in its wake to the east of a weak cold front. The most surface-based severe-favorable setup may materialize across central/eastern Nebraska into Monday late afternoon/early evening, and possibly into parts of South Dakota. Seasonally strong deep-layer shear will support potentially intense supercells, with a risk for all severe hazards. Some upscale growth is possible into the evening as storms spread eastward, with a continued severe risk potentially reaching parts of Minnesota and Iowa Monday night. ...Southeast States... Some strong to locally severe storms capable of wind damage may occur Monday afternoon through early evening within a moderately unstable environment along and south of the southward-sagging front. Current thinking is that this risk is most probable across southern South Carolina and southern/eastern Georgia into northern Florida. ..Guyer.. 06/29/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0244 AM CDT Sat Jun 29 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Severe thunderstorms will be possible on Monday across the northern/central Plains including parts of Nebraska and South Dakota. ...Northern/central Plains and Upper Midwest... A mid/upper-level trough is expected to overspread the region with appreciable height falls, particularly by early summertime standards, as far south as Nebraska and Iowa. A surface low is forecast to deepen over the Dakotas, along a surface trough. The influences of early day convection will probably be a modulating factor and point of uncertainty spatially, but a warm front should effectively transition north-northeastward during the day, with very rich low-level moisture in its wake to the east of a weak cold front. The most surface-based severe-favorable setup may materialize across central/eastern Nebraska into Monday late afternoon/early evening, and possibly into parts of South Dakota. Seasonally strong deep-layer shear will support potentially intense supercells, with a risk for all severe hazards. Some upscale growth is possible into the evening as storms spread eastward, with a continued severe risk potentially reaching parts of Minnesota and Iowa Monday night. ...Southeast States... Some strong to locally severe storms capable of wind damage may occur Monday afternoon through early evening within a moderately unstable environment along and south of the southward-sagging front. Current thinking is that this risk is most probable across southern South Carolina and southern/eastern Georgia into northern Florida. ..Guyer.. 06/29/2024 Read more

MD 1471 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHWESTERN AND SOUTH CENTRAL NEBRASKA
Mesoscale Discussion 1471 NWS Storm Prediction Center Norman OK 0151 AM CDT Sat Jun 29 2024 Areas affected...parts of southwestern and south central Nebraska Concerning...Severe potential...Watch unlikely Valid 290651Z - 290845Z Probability of Watch Issuance...20 percent SUMMARY...An isolated intense supercell may continue to pose a risk for large hail (up to 2+ inches in diameter) and potentially damaging wind gusts across and east-southeast of the Lexington vicinity through 2 to 3 AM CDT. Thereafter, it seems probable that it will weaken. Trends are being monitored, but a severe weather watch is not currently anticipated. DISCUSSION...Forcing for recent intense, isolated supercell development to the east southeast of North Platte is unclear. It appears focused within a corridor of higher boundary-layer moisture content supportive of sizable CAPE up to 2000 J/kg, along baroclinic zone where low-level warm advection may have become enhanced. Aided by strong shear, radar data suggests that this cell has been producing severe hail, and this east-southeastward propagating cell may eventually pose a risk for locally strong surface gusts if it is maintained long enough. However, based on the Rapid Refresh, the developing frontal zone is in the process of surging southward at a pace that may tend to undercut the storm and contribute to stabilizing trends within the next couple of hours. ..Kerr/Edwards.. 06/29/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF... LAT...LON 40960011 40999960 40869855 40479888 40610038 40760037 40960011 Read more