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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Wed Apr 17 2024 Valid 171700Z - 181200Z No changes to the ongoing forecast. ..Wendt.. 04/17/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Wed Apr 17 2024/ ...Synopsis... Behind the weakening upper low, flow aloft is forecast to trend more zonal and weaken as the general pattern de-amplifies. Still, some stronger westerly flow will linger over parts of the southern Rockies through the forecast period. A lee low will bolster low-level surface flow off the Rockies and into the adjacent High Plains this afternoon and evening. Warm temperatures are expected along with the dry downslope flow. This should support afternoon min RH values of 10-15% across much of eastern NM and southern CO. While winds are not expected to be overly strong (generally 10-15 mph) a few hours of dry and breezy conditions are possible. With area fuels dry, elevated fire-weather conditions are likely. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Wed Apr 17 2024 Valid 171700Z - 181200Z No changes to the ongoing forecast. ..Wendt.. 04/17/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Wed Apr 17 2024/ ...Synopsis... Behind the weakening upper low, flow aloft is forecast to trend more zonal and weaken as the general pattern de-amplifies. Still, some stronger westerly flow will linger over parts of the southern Rockies through the forecast period. A lee low will bolster low-level surface flow off the Rockies and into the adjacent High Plains this afternoon and evening. Warm temperatures are expected along with the dry downslope flow. This should support afternoon min RH values of 10-15% across much of eastern NM and southern CO. While winds are not expected to be overly strong (generally 10-15 mph) a few hours of dry and breezy conditions are possible. With area fuels dry, elevated fire-weather conditions are likely. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Wed Apr 17 2024 Valid 171700Z - 181200Z No changes to the ongoing forecast. ..Wendt.. 04/17/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Wed Apr 17 2024/ ...Synopsis... Behind the weakening upper low, flow aloft is forecast to trend more zonal and weaken as the general pattern de-amplifies. Still, some stronger westerly flow will linger over parts of the southern Rockies through the forecast period. A lee low will bolster low-level surface flow off the Rockies and into the adjacent High Plains this afternoon and evening. Warm temperatures are expected along with the dry downslope flow. This should support afternoon min RH values of 10-15% across much of eastern NM and southern CO. While winds are not expected to be overly strong (generally 10-15 mph) a few hours of dry and breezy conditions are possible. With area fuels dry, elevated fire-weather conditions are likely. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Wed Apr 17 2024 Valid 171700Z - 181200Z No changes to the ongoing forecast. ..Wendt.. 04/17/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Wed Apr 17 2024/ ...Synopsis... Behind the weakening upper low, flow aloft is forecast to trend more zonal and weaken as the general pattern de-amplifies. Still, some stronger westerly flow will linger over parts of the southern Rockies through the forecast period. A lee low will bolster low-level surface flow off the Rockies and into the adjacent High Plains this afternoon and evening. Warm temperatures are expected along with the dry downslope flow. This should support afternoon min RH values of 10-15% across much of eastern NM and southern CO. While winds are not expected to be overly strong (generally 10-15 mph) a few hours of dry and breezy conditions are possible. With area fuels dry, elevated fire-weather conditions are likely. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Wed Apr 17 2024 Valid 171700Z - 181200Z No changes to the ongoing forecast. ..Wendt.. 04/17/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Wed Apr 17 2024/ ...Synopsis... Behind the weakening upper low, flow aloft is forecast to trend more zonal and weaken as the general pattern de-amplifies. Still, some stronger westerly flow will linger over parts of the southern Rockies through the forecast period. A lee low will bolster low-level surface flow off the Rockies and into the adjacent High Plains this afternoon and evening. Warm temperatures are expected along with the dry downslope flow. This should support afternoon min RH values of 10-15% across much of eastern NM and southern CO. While winds are not expected to be overly strong (generally 10-15 mph) a few hours of dry and breezy conditions are possible. With area fuels dry, elevated fire-weather conditions are likely. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0121 Status Updates
STATUS FOR WATCH 0121 HAS NOT BEEN ISSUED YET Read more

WW 0121 Status Updates
STATUS FOR WATCH 0121 HAS NOT BEEN ISSUED YET Read more

No watches are valid as of Wed Apr 17 15:46:02 UTC 2024.

MD 0469 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR NORTHEAST IL INTO NORTHERN IN AND SOUTHWEST LOWER MI
Mesoscale Discussion 0469 NWS Storm Prediction Center Norman OK 0940 AM CDT Wed Apr 17 2024 Areas affected...far northeast IL into northern IN and southwest Lower MI Concerning...Severe potential...Watch unlikely Valid 171440Z - 171545Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorms will gradually develop this morning, mainly across northwest IN into far southwest MI. Severe potential should remain low the next 1-2 hours. DISCUSSION...Visible satellite data and regional radar indicates convection is beginning to deepen ahead of the eastward advancing cold front. This activity will likely only slowly continue to intensify through the morning. Nevertheless, temperatures are already in the upper 60s to low 70s with weak instability noted in 14z mesoanalysis. Severe potential is expected to remain low over the next couple of hours, but gusty winds to 45 mph will be possible with these showers and isolated thunderstorms. A watch is not expected in the short term, but severe potential should increase by around midday/early afternoon downstream. ..Leitman/Mosier.. 04/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...GRR...IND...LOT...ILX... LAT...LON 42578540 42048529 41068556 40608584 40178658 39888731 39998769 40208784 40688778 41878710 42428634 42778587 42768560 42578540 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Apr 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains. ...Synopsis... An upper trough/low over the Upper Midwest this morning will continue to move east-northeastward across the Great Lakes and OH Valley today while gradually de-amplifying/weakening. An associated 40-60 kt mid-level jet will accompany this trough and overspread much of the OH/TN Valleys. At the surface, a low over southeastern MN/western WI should continue to gradually occlude through the day in tandem with the weakening upper cyclone. An attendant cold front will sweep eastward over the Lower Great Lakes/OH Valley through this evening, while a warm front advances as far north as parts of Lower MI and perhaps far western NY. ...Lower Michigan into the Ohio/Tennessee Valleys and Mid-Atlantic... Upper 50s to low 60s surface dewpoints are expected to be in place ahead of the cold front late this morning/early afternoon. A pronounced mid-level dry slot evident on water vapor satellite imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the boundary layer gradually warms/moistens, around 1000-1500 J/kg of MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of deep-layer shear and updraft organization. Current expectations are for convection to develop along or just ahead of the cold front by early afternoon, and subsequently spread quickly east-northeastward across Lower MI, OH, and western PA through this evening. Tendency may be for thunderstorms to quickly organize into a line, especially across Lower MI which will be in closer proximity to the large-scale ascent attendant to the upper trough/low. If this evolution occurs, then severe/damaging winds would be the main threat with this activity. Have expanded the Marginal and Slight Risks northward across Lower MI to account for this potential. Farther south across eastern IN and OH, forcing will gradually become more limited, which may allow for somewhat lower thunderstorm coverage initially. Even so, deep-layer shear will be strong enough to support supercells, with large hail, damaging wind, and a few tornadoes all possible. The best tornado potential may be focused across parts of southeastern Lower MI and northern OH, in closer proximity to the warm front and greater low-level shear. Some upscale growth may also occur with this activity as it moves into eastern OH and western PA, with a potentially greater threat for damaging winds through the early evening before convection eventually weakens. Overall convective coverage should be lower across the TN Valley into the Southeast, with weaker large-scale ascent present over these regions. Still, isolated strong thunderstorms may occur this afternoon and early evening in a weakly unstable but strong deep-layer shear environment. Occasional hail and gusty winds appear possible with the more robust cores. Based on latest guidance trends, have trimmed the western extent of the Marginal Risk over western KY/TN and northern MS. Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central PA), a well-mixed boundary layer and steep low-level lapse rates forecast by some guidance may support occasional strong to damaging winds with convection spreading eastward off the higher terrain of the Appalachians and Blue Ridge Mountains. With limited instability, the overall severe wind threat will likely remain isolated. ...Nebraska/Kansas into Iowa/Missouri... An upper-level trough will move eastward across the north-central CONUS tonight. A 40-45 kt southerly low-level jet will develop this evening across parts of the southern/central Plains in response. Thunderstorms should eventually initiate near the northern edge of the low-level jet late this evening from central KS into far southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong shear in the cloud-bearing layer should support some threat for large hail with this mainly elevated convection. The large hail threat should to be greatest in the 04Z to 08Z time window with initial development, but it may persist through the end of the period. If convection can grow upscale into a small bowing cluster, then isolated damaging winds may also occur. A conditional threat for a supercell or two will exist farther south across south-central/southeastern KS into far northeastern OK. Here, modest low-level convergence along the intersection of a developing warm front and dryline may be sufficient to initiate isolated convection early this evening as the low-level jet strengthens. If this occurs, then all severe hazards appear possible. ...Texas... Very isolated thunderstorms may develop late this afternoon and early evening across parts of south-central into central TX along a surface dryline. If any convection can be sustained, it could produce severe winds and hail. But, this threat currently appears too conditional and uncertain to add low severe probabilities. ..Gleason/Bentley.. 04/17/2024 Read more