Aggregator

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jun 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST... ...SUMMARY... Scattered severe thunderstorms are expected over parts of the Upper Midwest this afternoon into tonight. Storms will be capable of large hail, and a cluster potentially capable of destructive wind gusts could develop over parts of Minnesota into Wisconsin. ...Upper Midwest... A mid-level trough will continue to transition eastward and modestly amplify over the Canadian Prairies, with southern-peripheral height falls and strengthening westerlies from North Dakota/northern Minnesota toward the Upper Great Lakes through tonight. In this same corridor, a weak MCV may be evolving this morning over eastern North Dakota/northwest Minnesota, while these scattered thunderstorms will probably also influence and somewhat hinder the effective north-northeastward of a warm front later today across Minnesota and Wisconsin. A very moist (low 70s F dewpoints) and unstable air mass will otherwise develop northeastward regionally in tandem with the warm front as surface cyclogenesis occurs across the Siouxland and southern Minnesota through evening. Upwards of 3000-5000 J/kg MLCAPE is expected within the warm sector, with very warm mid-level temperatures associated with the elevated mixed-layer plume likely limiting warm sector development away from (south of) the immediate triple point and cold front/warm front vicinity. Multiple convective scenarios are possible late this afternoon through tonight. For one, as the air mass recovers from the early day storms, widely scattered surface-based thunderstorms may develop by late afternoon near the eastward-advancing cold front within the relatively narrow warm sector from far eastern North Dakota into northern/western Minnesota. Any storms that do develop will likely organize into supercells given strong wind profiles and the large buoyancy. Large to very large hail, damaging winds and perhaps a tornado would be possible with any supercells, especially with storms in proximity to the warm front. Additionally, on the southern fringe of the early scattered early day convection (and related cloud cover) from eastern North Dakota into northern Minnesota, storms may form near an effective triple point/differential heating reinforced warm front. Such initial development could occur across south-central/southeast Minnesota, with robust instability/seasonally strong shear potentially supportive of an initial mode of intense supercells, with subsequent upscale growth in an MCS with heightened damaging wind potential. Additional mostly elevated storms could form tonight from eastern Minnesota into northern/central Wisconsin, on the immediate cool side of the surface baroclinic gradient as a nocturnally increasingly low-level jet heightens isentropic ascent. These storms may also pose a large hail and damaging wind risk through the overnight. An upgrade to Enhanced Risk (Level 3/5) may be warranted pending morning observational/guidance trends, potentially including a corridor across south-central/southern Minnesota and west/southwest Wisconsin, where a semi-focused swath of potentially significant damaging winds appears plausible. ...Central Plains and Black Hills... Very warm surface temperatures are expected ahead of the weakening cold front across central Nebraska and northern Kansas. At least isolated high-based storms are expected to develop within a hot/deeply mixed boundary layer environment. With generally weak mid-level flow across the region, storms may quickly become outflow dominant, but steep low/mid-tropospheric lapse rates will support isolated severe wind gusts. The strongest updrafts may also be capable of producing some hail. Other potentially severe storms will also be possible over the Black Hills/northeast Wyoming with weak low-level upslope flow in the post-frontal environment. Modest low-level moisture and only glancing upper-level support suggest storm coverage will remain isolated, although severe hail/strong winds will be possible. ...Carolinas and far southeast Virginia... At the base of departing east coast trough, subtle height falls atop a warm and unstable air mass will support scattered afternoon thunderstorms across much of the eastern Carolinas and far southeast Virginia along a weak surface cold front. Enhanced flow aloft and surface convergence near the front should be sufficient for transient storm organization into multicell clusters or a weak supercell. Steepening low-level lapse rates and the high PWAT air mass will favor heavily water and hail-loaded downdrafts capable of isolated damaging gusts. Storms should begin to move offshore by early evening ending the severe risk. ..Guyer/Mosier.. 06/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jun 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST... ...SUMMARY... Scattered severe thunderstorms are expected over parts of the Upper Midwest this afternoon into tonight. Storms will be capable of large hail, and a cluster potentially capable of destructive wind gusts could develop over parts of Minnesota into Wisconsin. ...Upper Midwest... A mid-level trough will continue to transition eastward and modestly amplify over the Canadian Prairies, with southern-peripheral height falls and strengthening westerlies from North Dakota/northern Minnesota toward the Upper Great Lakes through tonight. In this same corridor, a weak MCV may be evolving this morning over eastern North Dakota/northwest Minnesota, while these scattered thunderstorms will probably also influence and somewhat hinder the effective north-northeastward of a warm front later today across Minnesota and Wisconsin. A very moist (low 70s F dewpoints) and unstable air mass will otherwise develop northeastward regionally in tandem with the warm front as surface cyclogenesis occurs across the Siouxland and southern Minnesota through evening. Upwards of 3000-5000 J/kg MLCAPE is expected within the warm sector, with very warm mid-level temperatures associated with the elevated mixed-layer plume likely limiting warm sector development away from (south of) the immediate triple point and cold front/warm front vicinity. Multiple convective scenarios are possible late this afternoon through tonight. For one, as the air mass recovers from the early day storms, widely scattered surface-based thunderstorms may develop by late afternoon near the eastward-advancing cold front within the relatively narrow warm sector from far eastern North Dakota into northern/western Minnesota. Any storms that do develop will likely organize into supercells given strong wind profiles and the large buoyancy. Large to very large hail, damaging winds and perhaps a tornado would be possible with any supercells, especially with storms in proximity to the warm front. Additionally, on the southern fringe of the early scattered early day convection (and related cloud cover) from eastern North Dakota into northern Minnesota, storms may form near an effective triple point/differential heating reinforced warm front. Such initial development could occur across south-central/southeast Minnesota, with robust instability/seasonally strong shear potentially supportive of an initial mode of intense supercells, with subsequent upscale growth in an MCS with heightened damaging wind potential. Additional mostly elevated storms could form tonight from eastern Minnesota into northern/central Wisconsin, on the immediate cool side of the surface baroclinic gradient as a nocturnally increasingly low-level jet heightens isentropic ascent. These storms may also pose a large hail and damaging wind risk through the overnight. An upgrade to Enhanced Risk (Level 3/5) may be warranted pending morning observational/guidance trends, potentially including a corridor across south-central/southern Minnesota and west/southwest Wisconsin, where a semi-focused swath of potentially significant damaging winds appears plausible. ...Central Plains and Black Hills... Very warm surface temperatures are expected ahead of the weakening cold front across central Nebraska and northern Kansas. At least isolated high-based storms are expected to develop within a hot/deeply mixed boundary layer environment. With generally weak mid-level flow across the region, storms may quickly become outflow dominant, but steep low/mid-tropospheric lapse rates will support isolated severe wind gusts. The strongest updrafts may also be capable of producing some hail. Other potentially severe storms will also be possible over the Black Hills/northeast Wyoming with weak low-level upslope flow in the post-frontal environment. Modest low-level moisture and only glancing upper-level support suggest storm coverage will remain isolated, although severe hail/strong winds will be possible. ...Carolinas and far southeast Virginia... At the base of departing east coast trough, subtle height falls atop a warm and unstable air mass will support scattered afternoon thunderstorms across much of the eastern Carolinas and far southeast Virginia along a weak surface cold front. Enhanced flow aloft and surface convergence near the front should be sufficient for transient storm organization into multicell clusters or a weak supercell. Steepening low-level lapse rates and the high PWAT air mass will favor heavily water and hail-loaded downdrafts capable of isolated damaging gusts. Storms should begin to move offshore by early evening ending the severe risk. ..Guyer/Mosier.. 06/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jun 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST... ...SUMMARY... Scattered severe thunderstorms are expected over parts of the Upper Midwest this afternoon into tonight. Storms will be capable of large hail, and a cluster potentially capable of destructive wind gusts could develop over parts of Minnesota into Wisconsin. ...Upper Midwest... A mid-level trough will continue to transition eastward and modestly amplify over the Canadian Prairies, with southern-peripheral height falls and strengthening westerlies from North Dakota/northern Minnesota toward the Upper Great Lakes through tonight. In this same corridor, a weak MCV may be evolving this morning over eastern North Dakota/northwest Minnesota, while these scattered thunderstorms will probably also influence and somewhat hinder the effective north-northeastward of a warm front later today across Minnesota and Wisconsin. A very moist (low 70s F dewpoints) and unstable air mass will otherwise develop northeastward regionally in tandem with the warm front as surface cyclogenesis occurs across the Siouxland and southern Minnesota through evening. Upwards of 3000-5000 J/kg MLCAPE is expected within the warm sector, with very warm mid-level temperatures associated with the elevated mixed-layer plume likely limiting warm sector development away from (south of) the immediate triple point and cold front/warm front vicinity. Multiple convective scenarios are possible late this afternoon through tonight. For one, as the air mass recovers from the early day storms, widely scattered surface-based thunderstorms may develop by late afternoon near the eastward-advancing cold front within the relatively narrow warm sector from far eastern North Dakota into northern/western Minnesota. Any storms that do develop will likely organize into supercells given strong wind profiles and the large buoyancy. Large to very large hail, damaging winds and perhaps a tornado would be possible with any supercells, especially with storms in proximity to the warm front. Additionally, on the southern fringe of the early scattered early day convection (and related cloud cover) from eastern North Dakota into northern Minnesota, storms may form near an effective triple point/differential heating reinforced warm front. Such initial development could occur across south-central/southeast Minnesota, with robust instability/seasonally strong shear potentially supportive of an initial mode of intense supercells, with subsequent upscale growth in an MCS with heightened damaging wind potential. Additional mostly elevated storms could form tonight from eastern Minnesota into northern/central Wisconsin, on the immediate cool side of the surface baroclinic gradient as a nocturnally increasingly low-level jet heightens isentropic ascent. These storms may also pose a large hail and damaging wind risk through the overnight. An upgrade to Enhanced Risk (Level 3/5) may be warranted pending morning observational/guidance trends, potentially including a corridor across south-central/southern Minnesota and west/southwest Wisconsin, where a semi-focused swath of potentially significant damaging winds appears plausible. ...Central Plains and Black Hills... Very warm surface temperatures are expected ahead of the weakening cold front across central Nebraska and northern Kansas. At least isolated high-based storms are expected to develop within a hot/deeply mixed boundary layer environment. With generally weak mid-level flow across the region, storms may quickly become outflow dominant, but steep low/mid-tropospheric lapse rates will support isolated severe wind gusts. The strongest updrafts may also be capable of producing some hail. Other potentially severe storms will also be possible over the Black Hills/northeast Wyoming with weak low-level upslope flow in the post-frontal environment. Modest low-level moisture and only glancing upper-level support suggest storm coverage will remain isolated, although severe hail/strong winds will be possible. ...Carolinas and far southeast Virginia... At the base of departing east coast trough, subtle height falls atop a warm and unstable air mass will support scattered afternoon thunderstorms across much of the eastern Carolinas and far southeast Virginia along a weak surface cold front. Enhanced flow aloft and surface convergence near the front should be sufficient for transient storm organization into multicell clusters or a weak supercell. Steepening low-level lapse rates and the high PWAT air mass will favor heavily water and hail-loaded downdrafts capable of isolated damaging gusts. Storms should begin to move offshore by early evening ending the severe risk. ..Guyer/Mosier.. 06/24/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jun 24 2024 Valid 241300Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST... ...SUMMARY... Scattered severe thunderstorms are expected over parts of the Upper Midwest this afternoon into tonight. Storms will be capable of large hail, and a cluster potentially capable of destructive wind gusts could develop over parts of Minnesota into Wisconsin. ...Upper Midwest... A mid-level trough will continue to transition eastward and modestly amplify over the Canadian Prairies, with southern-peripheral height falls and strengthening westerlies from North Dakota/northern Minnesota toward the Upper Great Lakes through tonight. In this same corridor, a weak MCV may be evolving this morning over eastern North Dakota/northwest Minnesota, while these scattered thunderstorms will probably also influence and somewhat hinder the effective north-northeastward of a warm front later today across Minnesota and Wisconsin. A very moist (low 70s F dewpoints) and unstable air mass will otherwise develop northeastward regionally in tandem with the warm front as surface cyclogenesis occurs across the Siouxland and southern Minnesota through evening. Upwards of 3000-5000 J/kg MLCAPE is expected within the warm sector, with very warm mid-level temperatures associated with the elevated mixed-layer plume likely limiting warm sector development away from (south of) the immediate triple point and cold front/warm front vicinity. Multiple convective scenarios are possible late this afternoon through tonight. For one, as the air mass recovers from the early day storms, widely scattered surface-based thunderstorms may develop by late afternoon near the eastward-advancing cold front within the relatively narrow warm sector from far eastern North Dakota into northern/western Minnesota. Any storms that do develop will likely organize into supercells given strong wind profiles and the large buoyancy. Large to very large hail, damaging winds and perhaps a tornado would be possible with any supercells, especially with storms in proximity to the warm front. Additionally, on the southern fringe of the early scattered early day convection (and related cloud cover) from eastern North Dakota into northern Minnesota, storms may form near an effective triple point/differential heating reinforced warm front. Such initial development could occur across south-central/southeast Minnesota, with robust instability/seasonally strong shear potentially supportive of an initial mode of intense supercells, with subsequent upscale growth in an MCS with heightened damaging wind potential. Additional mostly elevated storms could form tonight from eastern Minnesota into northern/central Wisconsin, on the immediate cool side of the surface baroclinic gradient as a nocturnally increasingly low-level jet heightens isentropic ascent. These storms may also pose a large hail and damaging wind risk through the overnight. An upgrade to Enhanced Risk (Level 3/5) may be warranted pending morning observational/guidance trends, potentially including a corridor across south-central/southern Minnesota and west/southwest Wisconsin, where a semi-focused swath of potentially significant damaging winds appears plausible. ...Central Plains and Black Hills... Very warm surface temperatures are expected ahead of the weakening cold front across central Nebraska and northern Kansas. At least isolated high-based storms are expected to develop within a hot/deeply mixed boundary layer environment. With generally weak mid-level flow across the region, storms may quickly become outflow dominant, but steep low/mid-tropospheric lapse rates will support isolated severe wind gusts. The strongest updrafts may also be capable of producing some hail. Other potentially severe storms will also be possible over the Black Hills/northeast Wyoming with weak low-level upslope flow in the post-frontal environment. Modest low-level moisture and only glancing upper-level support suggest storm coverage will remain isolated, although severe hail/strong winds will be possible. ...Carolinas and far southeast Virginia... At the base of departing east coast trough, subtle height falls atop a warm and unstable air mass will support scattered afternoon thunderstorms across much of the eastern Carolinas and far southeast Virginia along a weak surface cold front. Enhanced flow aloft and surface convergence near the front should be sufficient for transient storm organization into multicell clusters or a weak supercell. Steepening low-level lapse rates and the high PWAT air mass will favor heavily water and hail-loaded downdrafts capable of isolated damaging gusts. Storms should begin to move offshore by early evening ending the severe risk. ..Guyer/Mosier.. 06/24/2024 Read more

000
ABPZ20 KNHC 241122
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Jun 24 2024

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

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

$$
Forecaster Hagen/Pasch

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. Read more

MD 1392 CONCERNING SEVERE THUNDERSTORM WATCH 450... FOR NORTH-CENTRAL NORTH DAKOTA
Mesoscale Discussion 1392 NWS Storm Prediction Center Norman OK 0313 AM CDT Mon Jun 24 2024 Areas affected...North-Central North Dakota Concerning...Severe Thunderstorm Watch 450... Valid 240813Z - 240945Z The severe weather threat for Severe Thunderstorm Watch 450 continues. SUMMARY...Large hail remains possible with the pair of supercells moving southeastward across north-central North Dakota. DISCUSSION...Elevated supercells continue to progress gradually southeastward across north-central North Dakota. Current storm motion with the storm over Bottineau County is around 35 kt. The storm farther west just crossing the international border is moving a bit slower, with its motion estimated at closer to 30 kt. Both of these supercells remain organized and intense, with recent MESH indicating severe hail (particularly with the westernmost cell). The lead/easternmost cell may begin weakening soon as it moves into a less buoyant airmass, although the organized character of this cell may allow it to persist farther east into greater stability than would usually be expected. The westernmost cell should be able to maintain it intensity for at least the next hour or so before it too begins to weaken. Large hail will remain possible with these storms, particularly the westernmost cell, for the next hour or two. Given the forecast weakening of these storms with eastern extent, a downstream watch is not currently anticipated, but convective trends will still be monitored closely. ..Mosier.. 06/24/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 49320220 49049952 48319896 47849977 47980102 48540242 49320220 Read more

MD 1391 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN MT...WESTERN NORTH DAKOTA
Mesoscale Discussion 1391 NWS Storm Prediction Center Norman OK 0140 AM CDT Mon Jun 24 2024 Areas affected...Eastern MT...Western North Dakota Concerning...Severe potential...Watch unlikely Valid 240640Z - 240845Z Probability of Watch Issuance...20 percent SUMMARY...A few instances of large hail are possible across eastern Montana and western North Dakota over the next few hours. DISCUSSION...Warm-air advection across a frontal zone across eastern MT has contributed to an increase in elevated thunderstorm activity over the past hour or so. Significant buoyancy exists downstream across far eastern MT and into western ND, supported primarily by steep mid-level lapse rates (i.e. 8.5 to 9 deg C per km) and modest mid-level moisture. Based on recent mesoanalysis, 0-6 km bulk shear is around 40 to 50 kt, with the resulting combination of vertical shear and buoyancy supportive of organized updrafts and a few elevated supercells. Given the buoyancy downstream, this activity may persist for the next few hours into far eastern MT and western ND, although the overall coverage may begin to decrease as storms become displaced east of the more favorable warm-air advection. Large hail is possible within the more organized storms, but the overall severe risk should remain isolated, likely precluding the need for a watch. ..Mosier/Guyer.. 06/24/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...BYZ...GGW... LAT...LON 46010390 46130558 46630703 47350750 48330655 48700544 48760452 48530346 48040242 46870156 46090162 46010390 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Mon Jun 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA INTO NORTHERN NJ AND SOUTHEAST NY... ...SUMMARY... Scattered damaging winds are possible over parts of the Northeast and northern Mid Atlantic on Wednesday. ...Upper Ohio Valley into the Northeast/Mid Atlantic... A mid/upper-level shortwave trough is forecast to move from the upper Midwest toward the lower Great Lakes and Northeast on Wednesday. Rather moist low-level westerly flow will support potential for moderate diurnal destabilization from OH into parts of the Northeast and northern Mid Atlantic. Scattered thunderstorm development will be possible Wednesday afternoon along/ahead of a cold front across parts of OH/PA and southern NY, which will spread eastward into the evening. Strengthening flow in the 700-500 mb layer will support sufficient effective shear for storm organization, with potential for a few organized clusters and perhaps a couple of supercells. Damaging wind and perhaps isolated hail will be possible, along with some potential for a brief tornado if a supercell can be sustained. A Slight Risk has been added for parts of PA into southeast NY and northern NJ, where the most favorable overlap of instability, storm coverage, and strengthening low/midlevel flow is currently anticipated. Diurnal storm coverage becomes increasingly uncertain with southward extent, but at least an isolated severe threat could extend into parts of the Mid Atlantic during the late afternoon and evening. ...Lower Ohio Valley into the Ozarks vicinity... Uncertainty regarding storm potential and evolution is quite high from the lower Ohio Valley vicinity into the Ozarks. There is some potential for an MCS (or its remnant) to be ongoing at the start of the period. An outflow-influenced front will be draped somewhere across the region through the day, to the south of a reinforcing cold front that will move southward from the upper Midwest. Northwesterly mid/upper-level flow will be in place across the region, though the strength of the flow and any embedded shortwave troughs may also be influenced by antecedent convection and potential development of any MCVs. Some redevelopment of storms will be possible near the front and any remaining outflow boundaries. The northwesterly flow regime may provide sufficient effective shear for some storm organization, with one or more clusters possible with a threat of damaging wind and perhaps some hail. ...Southeast WY/northeast CO into central High Plains... Moist low-level southeasterly flow is expected on Wednesday from eastern CO/WY into the NE Panhandle, in the wake of a cold frontal passage. Moderate destabilization will be possible during the afternoon within this regime. While the region will initially be under the influence of an upper-level ridge over the southern Rockies, guidance suggests potential for a low-amplitude shortwave trough to crest the ridge from WY into western NY. This will support potential for at least isolated thunderstorm development. Midlevel flow may remain rather modest, but sufficient veering with height will support sufficient effective shear for storm organization, including some supercell potential with a threat of large hail and localized severe gusts. A strengthening nocturnal low-level jet could support some upscale growth, which could spread at least isolated severe-gust potential into parts of southwest NE and western KS. ..Dean.. 06/24/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Mon Jun 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA INTO NORTHERN NJ AND SOUTHEAST NY... ...SUMMARY... Scattered damaging winds are possible over parts of the Northeast and northern Mid Atlantic on Wednesday. ...Upper Ohio Valley into the Northeast/Mid Atlantic... A mid/upper-level shortwave trough is forecast to move from the upper Midwest toward the lower Great Lakes and Northeast on Wednesday. Rather moist low-level westerly flow will support potential for moderate diurnal destabilization from OH into parts of the Northeast and northern Mid Atlantic. Scattered thunderstorm development will be possible Wednesday afternoon along/ahead of a cold front across parts of OH/PA and southern NY, which will spread eastward into the evening. Strengthening flow in the 700-500 mb layer will support sufficient effective shear for storm organization, with potential for a few organized clusters and perhaps a couple of supercells. Damaging wind and perhaps isolated hail will be possible, along with some potential for a brief tornado if a supercell can be sustained. A Slight Risk has been added for parts of PA into southeast NY and northern NJ, where the most favorable overlap of instability, storm coverage, and strengthening low/midlevel flow is currently anticipated. Diurnal storm coverage becomes increasingly uncertain with southward extent, but at least an isolated severe threat could extend into parts of the Mid Atlantic during the late afternoon and evening. ...Lower Ohio Valley into the Ozarks vicinity... Uncertainty regarding storm potential and evolution is quite high from the lower Ohio Valley vicinity into the Ozarks. There is some potential for an MCS (or its remnant) to be ongoing at the start of the period. An outflow-influenced front will be draped somewhere across the region through the day, to the south of a reinforcing cold front that will move southward from the upper Midwest. Northwesterly mid/upper-level flow will be in place across the region, though the strength of the flow and any embedded shortwave troughs may also be influenced by antecedent convection and potential development of any MCVs. Some redevelopment of storms will be possible near the front and any remaining outflow boundaries. The northwesterly flow regime may provide sufficient effective shear for some storm organization, with one or more clusters possible with a threat of damaging wind and perhaps some hail. ...Southeast WY/northeast CO into central High Plains... Moist low-level southeasterly flow is expected on Wednesday from eastern CO/WY into the NE Panhandle, in the wake of a cold frontal passage. Moderate destabilization will be possible during the afternoon within this regime. While the region will initially be under the influence of an upper-level ridge over the southern Rockies, guidance suggests potential for a low-amplitude shortwave trough to crest the ridge from WY into western NY. This will support potential for at least isolated thunderstorm development. Midlevel flow may remain rather modest, but sufficient veering with height will support sufficient effective shear for storm organization, including some supercell potential with a threat of large hail and localized severe gusts. A strengthening nocturnal low-level jet could support some upscale growth, which could spread at least isolated severe-gust potential into parts of southwest NE and western KS. ..Dean.. 06/24/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Mon Jun 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA INTO NORTHERN NJ AND SOUTHEAST NY... ...SUMMARY... Scattered damaging winds are possible over parts of the Northeast and northern Mid Atlantic on Wednesday. ...Upper Ohio Valley into the Northeast/Mid Atlantic... A mid/upper-level shortwave trough is forecast to move from the upper Midwest toward the lower Great Lakes and Northeast on Wednesday. Rather moist low-level westerly flow will support potential for moderate diurnal destabilization from OH into parts of the Northeast and northern Mid Atlantic. Scattered thunderstorm development will be possible Wednesday afternoon along/ahead of a cold front across parts of OH/PA and southern NY, which will spread eastward into the evening. Strengthening flow in the 700-500 mb layer will support sufficient effective shear for storm organization, with potential for a few organized clusters and perhaps a couple of supercells. Damaging wind and perhaps isolated hail will be possible, along with some potential for a brief tornado if a supercell can be sustained. A Slight Risk has been added for parts of PA into southeast NY and northern NJ, where the most favorable overlap of instability, storm coverage, and strengthening low/midlevel flow is currently anticipated. Diurnal storm coverage becomes increasingly uncertain with southward extent, but at least an isolated severe threat could extend into parts of the Mid Atlantic during the late afternoon and evening. ...Lower Ohio Valley into the Ozarks vicinity... Uncertainty regarding storm potential and evolution is quite high from the lower Ohio Valley vicinity into the Ozarks. There is some potential for an MCS (or its remnant) to be ongoing at the start of the period. An outflow-influenced front will be draped somewhere across the region through the day, to the south of a reinforcing cold front that will move southward from the upper Midwest. Northwesterly mid/upper-level flow will be in place across the region, though the strength of the flow and any embedded shortwave troughs may also be influenced by antecedent convection and potential development of any MCVs. Some redevelopment of storms will be possible near the front and any remaining outflow boundaries. The northwesterly flow regime may provide sufficient effective shear for some storm organization, with one or more clusters possible with a threat of damaging wind and perhaps some hail. ...Southeast WY/northeast CO into central High Plains... Moist low-level southeasterly flow is expected on Wednesday from eastern CO/WY into the NE Panhandle, in the wake of a cold frontal passage. Moderate destabilization will be possible during the afternoon within this regime. While the region will initially be under the influence of an upper-level ridge over the southern Rockies, guidance suggests potential for a low-amplitude shortwave trough to crest the ridge from WY into western NY. This will support potential for at least isolated thunderstorm development. Midlevel flow may remain rather modest, but sufficient veering with height will support sufficient effective shear for storm organization, including some supercell potential with a threat of large hail and localized severe gusts. A strengthening nocturnal low-level jet could support some upscale growth, which could spread at least isolated severe-gust potential into parts of southwest NE and western KS. ..Dean.. 06/24/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Mon Jun 24 2024 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA INTO NORTHERN NJ AND SOUTHEAST NY... ...SUMMARY... Scattered damaging winds are possible over parts of the Northeast and northern Mid Atlantic on Wednesday. ...Upper Ohio Valley into the Northeast/Mid Atlantic... A mid/upper-level shortwave trough is forecast to move from the upper Midwest toward the lower Great Lakes and Northeast on Wednesday. Rather moist low-level westerly flow will support potential for moderate diurnal destabilization from OH into parts of the Northeast and northern Mid Atlantic. Scattered thunderstorm development will be possible Wednesday afternoon along/ahead of a cold front across parts of OH/PA and southern NY, which will spread eastward into the evening. Strengthening flow in the 700-500 mb layer will support sufficient effective shear for storm organization, with potential for a few organized clusters and perhaps a couple of supercells. Damaging wind and perhaps isolated hail will be possible, along with some potential for a brief tornado if a supercell can be sustained. A Slight Risk has been added for parts of PA into southeast NY and northern NJ, where the most favorable overlap of instability, storm coverage, and strengthening low/midlevel flow is currently anticipated. Diurnal storm coverage becomes increasingly uncertain with southward extent, but at least an isolated severe threat could extend into parts of the Mid Atlantic during the late afternoon and evening. ...Lower Ohio Valley into the Ozarks vicinity... Uncertainty regarding storm potential and evolution is quite high from the lower Ohio Valley vicinity into the Ozarks. There is some potential for an MCS (or its remnant) to be ongoing at the start of the period. An outflow-influenced front will be draped somewhere across the region through the day, to the south of a reinforcing cold front that will move southward from the upper Midwest. Northwesterly mid/upper-level flow will be in place across the region, though the strength of the flow and any embedded shortwave troughs may also be influenced by antecedent convection and potential development of any MCVs. Some redevelopment of storms will be possible near the front and any remaining outflow boundaries. The northwesterly flow regime may provide sufficient effective shear for some storm organization, with one or more clusters possible with a threat of damaging wind and perhaps some hail. ...Southeast WY/northeast CO into central High Plains... Moist low-level southeasterly flow is expected on Wednesday from eastern CO/WY into the NE Panhandle, in the wake of a cold frontal passage. Moderate destabilization will be possible during the afternoon within this regime. While the region will initially be under the influence of an upper-level ridge over the southern Rockies, guidance suggests potential for a low-amplitude shortwave trough to crest the ridge from WY into western NY. This will support potential for at least isolated thunderstorm development. Midlevel flow may remain rather modest, but sufficient veering with height will support sufficient effective shear for storm organization, including some supercell potential with a threat of large hail and localized severe gusts. A strengthening nocturnal low-level jet could support some upscale growth, which could spread at least isolated severe-gust potential into parts of southwest NE and western KS. ..Dean.. 06/24/2024 Read more