Severe Storms

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH TEXAS...SOUTHEAST OKLAHOMA...AND MUCH OF ARKANSAS TO THE MISSOURI BOOTHEEL VICINITY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes vicinity on Wednesday. The highest concentration of damaging gusts and large to very large hail is expected from north Texas to the Missouri Bootheel vicinity. ...Synopsis... An upper shortwave trough will move northeast across the Upper Midwest/Great Lakes vicinity on Wednesday. Meanwhile, convectively enhanced vorticity maxima from the Day 1/Tue period will develop east/northeast across parts of the Ohio Valley/Lower Great Lakes area in broad southwesterly deep-layer flow. Further south, broad, enhanced southwesterly flow will persist over the southern Plains to the Mid-South. One or more shortwave impulses are expected to float through this area ahead of a deepening large-scale western U.S. upper trough. At the surface, an occluding low near the MN/Ontario border will lift north through the period, with a weak surface trough extending into parts of the upper Ohio Valley and lower Great Lakes. The northern extent of a surface cold front will progress eastward across the Great Lakes vicinity. Meanwhile, the front will mainly stall from IN/southern IL into central OK and northwest TX. A dryline will move east into central TX. These boundaries will become the focus for thunderstorm development during the afternoon. ...Texas to Southern IL... A moisture-rich boundary layer will be present, with dewpoints in the upper 60s to low 70s F common. Atop this moist boundary layer, steep midlevel lapse rates around 8 C/km are forecast. This will result in strong to extreme instability (2500-4000 J/kg MLCAPE). Vertical shear will be favorable for supercells, with modestly enlarged low-level hodographs become elongated/straight above 3 km. Significant hail (greater than 2 inch diameter) will be possible with initial supercell development. How long semi-discrete supercells will be maintained is a bit uncertain. Upscale development into bowing segments will likely occur, resulting in an increasing damaging wind risk with time. A 35-45 kt southwesterly low-level jet is forecast to increase by early evening. This will support increasing 0-1 km SRH (to around 200 m2/s2) and a few tornadoes will be possible. A strong tornado cannot be ruled out, especially over parts of AR into north Texas. ...IN/KY to the Lower Great Lakes... Forcing for ascent across the region will mainly be provided by any MCVs from remnant Day 1/Tue convection floating through southwesterly flow, and the eastward-advancing cold front. A moist airmass with dewpoints in mid/upper 60s will be present over IN/OH/KY, with low/mid 60s extending northeast into NY/PA and vicinity. Strong heating and a plume of steep midlevel lapse rates will support moderate destabilization during the late morning/afternoon. Vertical shear will be sufficient for organized cells, though decreasing with northeast extent into eastern NY and the Mid-Atlantic vicinity. Isolated damaging gusts and marginal hail will be possible with thunderstorms into early evening. ..Leitman.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue May 21 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PARTS OF IOWA...NORTHERN MISSOURI...NORTHWEST ILLINOIS...SOUTHWEST WISCONSIN...AND FAR SOUTHEAST MINNESOTA... ...SUMMARY... An outbreak of severe thunderstorms, including the potential for strong tornadoes, is probable today, peaking in the afternoon to early evening. The area most likely to be impacted will include the Mid to Lower Missouri Valley across the Mid to Upper Mississippi Valley to the Lake Michigan vicinity. ...Mid-Lower MO Valley into the western Great Lakes... An MCS and other remnant storm clusters are expected to be ongoing across parts of the Mid-MO Valley to Upper MS Valley at 12Z. How exactly this morning activity evolves eastward is somewhat uncertain. An initial bout of severe wind and hail may persist with this activity through midday. This will likely be over a focused mesoscale corridor, given a stout elevated mixed layer to its south and progressively limited instability to the north. Quick air mass recovery is expected in the wake of this early-day convection within a progressive/highly dynamic synoptic pattern. Pronounced surface cyclogenesis is expected with amplification of a vigorous shortwave trough from the central High Plains to the Upper MS Valley. This will yield substantial amplification of low to mid-level flow, with a belt of 70+ kt 500-mb winds extending from eastern KS and western MO through at least IA this afternoon. As the surface cyclone deepens, an attendant cold front will surge eastward into central IA through northwest MO by 00Z. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Initial supercell development should occur near the deepening surface cyclone by midday to early afternoon over the Mid-MO Valley. Increasingly widespread thunderstorm development is expected through the afternoon from the Upper MS Valley southward to the Lower MO Valley. Deep-layer shear will support an initial mixed mode of semi-discrete supercells and embedded supercells in clusters. But by late afternoon, upscale growth into a fast-moving arc of bowing line segments and embedded supercells is expected. Additional supercells should also form downstream along the effective warm front/remnant large-scale outflow that advances north in southern to central WI. Very large hail potential will be most likely with the initial supercell development, and with southern extent where semi-discrete storms should persist longest. Tornadoes, some of which should be strong, appear most probable from northern MO northward into southeast MN and southwest to central WI from both supercell and mesovortex processes. How far north strong-tornado potential can be realized will be modulated by the degree of destabilization in the wake of the early-day convection, but low-level SRH will be quite large. Damaging winds will become increasingly likely later in the afternoon into the evening with gusts of 75-90 mph possible as a well-organized QLCS forms. This should tend to be maximized across parts of central/eastern IA into western IL and northern MO. QLCS intensity should subside after dusk, as convection outpaces larger buoyancy, but a damaging wind threat could persist into Lower MI through the Mid-MO Valley. ...Ozarks to central TX... Convective coverage will decrease with southward extent as large-scale ascent focuses northward toward the Upper MS Valley and western Great Lakes. Nevertheless, scattered severe storms are possible during the late afternoon/evening near where the cold front overtakes the dryline in the Ozarks. More isolated convective coverage is expected southwestward along the dryline in central TX. Large buoyancy and ample deep-layer shear will support a primary threat of very large hail in TX. While a mix of large hail, damaging winds, and a few tornadoes will be possible over the Ozarks. ...New England and northeast NY... A low-amplitude shortwave impulse/remnant MCV will move across southern QC and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern NY into ME. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. Modest MLCAPE and effective shear from 30-35 kt will support a few organized cells. Moderately elongated hodographs suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Grams/Barnes.. 05/21/2024 Read more

MD 0863 CONCERNING SEVERE THUNDERSTORM WATCH 272... FOR NORTHERN IOWA AND SOUTHERN MINNESOTA
Mesoscale Discussion 0863 NWS Storm Prediction Center Norman OK 1134 PM CDT Mon May 20 2024 Areas affected...northern Iowa and southern Minnesota Concerning...Severe Thunderstorm Watch 272... Valid 210434Z - 210600Z The severe weather threat for Severe Thunderstorm Watch 272 continues. SUMMARY...A new severe weather watch does not appear needed, but WW 272 could be locally extended in time for an hour or two. Thunderstorms are expected to remain rather disorganized with diminishing intensities into the overnight hours. DISCUSSION...Ongoing storms are generally embedded with rather modest southwesterly deep-layer mean flow on the order of 20 kt or a bit less. But, due to pronounced veering of wind fields with height, vertical shear may be contributing to the maintenance of vigorous convection. Even as low-level warm advection maintains lift into the overnight hours, it does appear, though, that the risk for severe hail and wind will begin to wane with further boundary-layer cooling. ..Kerr.. 05/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX...DMX...FSD... LAT...LON 42889602 43359555 44169324 44159209 43359195 42889250 42259460 42159550 42889602 Read more