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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Thu May 15 2025 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ...SUMMARY... Severe thunderstorms are expected across parts of the upper Mississippi River Valley and Great Lakes this afternoon and evening. Tornadoes, some of which could be strong, and very large hail and damaging winds will be possible. Severe thunderstorms are also expected through the lower Ohio River Valley, Ozarks and in parts of the Mid-Atlantic. ...20z Update... Only minor changes were made to trim probabilities behind ongoing convective activity with this update. The Enhanced Risk across the Midwest remains unchanged. Thunderstorm activity has been ongoing in this region, with reports of a couple of tornadoes in western Minnesota. Expect thunderstorm activity to continue to strengthen in this area. See MCD#791 for more information on the short term threats. See previous discussion for more information concerning the broader Slight Risk across the Mid to upper Mississippi Valley and in the Central Appalachians and Mid-Atlantic below. ..Thornton/Mosier.. 05/15/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/ ...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley... Recent satellite imagery shows an upper low over SD, with a negatively tilted shortwave trough moving into the Mid MO Valley. Surface analysis places an occluded surface low associated with this system over southeast ND, with an occluded front extending southeastward to a triple point over far southeast SD. A cold front extends south-southeastward from this front across far western IA and into far northeast MO before arcing more southwestward across far western MO and more southwestward across western OK. A warm front extends easterward from this triple point across southern MN and then more southeastward across southwest WI and northern IL. These boundaries, including the occluded front, will all act in tandem with increasing large-scale forcing for ascent to force thunderstorm development this afternoon and evening. The ongoing storms from eastern SD into central MN are confirmation of the buoyancy sampled in the 12Z MPX sounding. Expectation is for instability to build across the region as heating and low-level moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first from the eastern Dakotas into MN, the occluded front as it shifts northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther southeast along the warm front across WI. Storms that develop in the vicinity of the occluded front will likely have elevated structures, with large hail as the primary risk. Some isolated very large hail (i.e. greater than 2" in diameter) is possible. Farther southeast, the corridor along the warm front appears very favorable for supercells capable of all severe hazards, including very large hail, strong wind gusts, and tornadoes. A locally higher tornado potential may exist from central into southeastern WI from 18Z-22Z. Deeper mixing is anticipated farther south into northern IL, but the overall environment will still support robust, organized updrafts. There may be some trend initially for these storms to quickly become outflow dominant, but strengthening mid-level flow across the region after 21Z should aid in maintaining a more organized mode. Upscale growth into a organized MCS appears probable after 00Z, with the potential for significant-severe gusts as this line moves eastward in southern Lower MI. The threat for damaging gusts and isolated hail will persist throughout the night across Lower MI and the middle/upper OH Valley. ...Ozarks into the TN Valley... Additional thunderstorm development is anticipated this afternoon across AR as a cold front pushes eastward across the region. Moderate to strong flow aloft should allow for storms to move off this boundary quickly into a strongly buoyant airmass downstream. Warm air aloft could limit overall storm longevity during the afternoon/early evening, but the warm/dry mid-levels are conducive for producing strong outflows capable of damaging gusts. Whether or not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN. Additional thunderstorms are possible during the evening and overnight in the wake of the front. Persistent steep mid-level lapse rates and strong shear will support large hail with some of these storms. ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Thu May 15 2025 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ...SUMMARY... Severe thunderstorms are expected across parts of the upper Mississippi River Valley and Great Lakes this afternoon and evening. Tornadoes, some of which could be strong, and very large hail and damaging winds will be possible. Severe thunderstorms are also expected through the lower Ohio River Valley, Ozarks and in parts of the Mid-Atlantic. ...20z Update... Only minor changes were made to trim probabilities behind ongoing convective activity with this update. The Enhanced Risk across the Midwest remains unchanged. Thunderstorm activity has been ongoing in this region, with reports of a couple of tornadoes in western Minnesota. Expect thunderstorm activity to continue to strengthen in this area. See MCD#791 for more information on the short term threats. See previous discussion for more information concerning the broader Slight Risk across the Mid to upper Mississippi Valley and in the Central Appalachians and Mid-Atlantic below. ..Thornton/Mosier.. 05/15/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/ ...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley... Recent satellite imagery shows an upper low over SD, with a negatively tilted shortwave trough moving into the Mid MO Valley. Surface analysis places an occluded surface low associated with this system over southeast ND, with an occluded front extending southeastward to a triple point over far southeast SD. A cold front extends south-southeastward from this front across far western IA and into far northeast MO before arcing more southwestward across far western MO and more southwestward across western OK. A warm front extends easterward from this triple point across southern MN and then more southeastward across southwest WI and northern IL. These boundaries, including the occluded front, will all act in tandem with increasing large-scale forcing for ascent to force thunderstorm development this afternoon and evening. The ongoing storms from eastern SD into central MN are confirmation of the buoyancy sampled in the 12Z MPX sounding. Expectation is for instability to build across the region as heating and low-level moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first from the eastern Dakotas into MN, the occluded front as it shifts northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther southeast along the warm front across WI. Storms that develop in the vicinity of the occluded front will likely have elevated structures, with large hail as the primary risk. Some isolated very large hail (i.e. greater than 2" in diameter) is possible. Farther southeast, the corridor along the warm front appears very favorable for supercells capable of all severe hazards, including very large hail, strong wind gusts, and tornadoes. A locally higher tornado potential may exist from central into southeastern WI from 18Z-22Z. Deeper mixing is anticipated farther south into northern IL, but the overall environment will still support robust, organized updrafts. There may be some trend initially for these storms to quickly become outflow dominant, but strengthening mid-level flow across the region after 21Z should aid in maintaining a more organized mode. Upscale growth into a organized MCS appears probable after 00Z, with the potential for significant-severe gusts as this line moves eastward in southern Lower MI. The threat for damaging gusts and isolated hail will persist throughout the night across Lower MI and the middle/upper OH Valley. ...Ozarks into the TN Valley... Additional thunderstorm development is anticipated this afternoon across AR as a cold front pushes eastward across the region. Moderate to strong flow aloft should allow for storms to move off this boundary quickly into a strongly buoyant airmass downstream. Warm air aloft could limit overall storm longevity during the afternoon/early evening, but the warm/dry mid-levels are conducive for producing strong outflows capable of damaging gusts. Whether or not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN. Additional thunderstorms are possible during the evening and overnight in the wake of the front. Persistent steep mid-level lapse rates and strong shear will support large hail with some of these storms. ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Thu May 15 2025 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ...SUMMARY... Severe thunderstorms are expected across parts of the upper Mississippi River Valley and Great Lakes this afternoon and evening. Tornadoes, some of which could be strong, and very large hail and damaging winds will be possible. Severe thunderstorms are also expected through the lower Ohio River Valley, Ozarks and in parts of the Mid-Atlantic. ...20z Update... Only minor changes were made to trim probabilities behind ongoing convective activity with this update. The Enhanced Risk across the Midwest remains unchanged. Thunderstorm activity has been ongoing in this region, with reports of a couple of tornadoes in western Minnesota. Expect thunderstorm activity to continue to strengthen in this area. See MCD#791 for more information on the short term threats. See previous discussion for more information concerning the broader Slight Risk across the Mid to upper Mississippi Valley and in the Central Appalachians and Mid-Atlantic below. ..Thornton/Mosier.. 05/15/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/ ...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley... Recent satellite imagery shows an upper low over SD, with a negatively tilted shortwave trough moving into the Mid MO Valley. Surface analysis places an occluded surface low associated with this system over southeast ND, with an occluded front extending southeastward to a triple point over far southeast SD. A cold front extends south-southeastward from this front across far western IA and into far northeast MO before arcing more southwestward across far western MO and more southwestward across western OK. A warm front extends easterward from this triple point across southern MN and then more southeastward across southwest WI and northern IL. These boundaries, including the occluded front, will all act in tandem with increasing large-scale forcing for ascent to force thunderstorm development this afternoon and evening. The ongoing storms from eastern SD into central MN are confirmation of the buoyancy sampled in the 12Z MPX sounding. Expectation is for instability to build across the region as heating and low-level moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first from the eastern Dakotas into MN, the occluded front as it shifts northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther southeast along the warm front across WI. Storms that develop in the vicinity of the occluded front will likely have elevated structures, with large hail as the primary risk. Some isolated very large hail (i.e. greater than 2" in diameter) is possible. Farther southeast, the corridor along the warm front appears very favorable for supercells capable of all severe hazards, including very large hail, strong wind gusts, and tornadoes. A locally higher tornado potential may exist from central into southeastern WI from 18Z-22Z. Deeper mixing is anticipated farther south into northern IL, but the overall environment will still support robust, organized updrafts. There may be some trend initially for these storms to quickly become outflow dominant, but strengthening mid-level flow across the region after 21Z should aid in maintaining a more organized mode. Upscale growth into a organized MCS appears probable after 00Z, with the potential for significant-severe gusts as this line moves eastward in southern Lower MI. The threat for damaging gusts and isolated hail will persist throughout the night across Lower MI and the middle/upper OH Valley. ...Ozarks into the TN Valley... Additional thunderstorm development is anticipated this afternoon across AR as a cold front pushes eastward across the region. Moderate to strong flow aloft should allow for storms to move off this boundary quickly into a strongly buoyant airmass downstream. Warm air aloft could limit overall storm longevity during the afternoon/early evening, but the warm/dry mid-levels are conducive for producing strong outflows capable of damaging gusts. Whether or not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN. Additional thunderstorms are possible during the evening and overnight in the wake of the front. Persistent steep mid-level lapse rates and strong shear will support large hail with some of these storms. ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Thu May 15 2025 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ...SUMMARY... Severe thunderstorms are expected across parts of the upper Mississippi River Valley and Great Lakes this afternoon and evening. Tornadoes, some of which could be strong, and very large hail and damaging winds will be possible. Severe thunderstorms are also expected through the lower Ohio River Valley, Ozarks and in parts of the Mid-Atlantic. ...20z Update... Only minor changes were made to trim probabilities behind ongoing convective activity with this update. The Enhanced Risk across the Midwest remains unchanged. Thunderstorm activity has been ongoing in this region, with reports of a couple of tornadoes in western Minnesota. Expect thunderstorm activity to continue to strengthen in this area. See MCD#791 for more information on the short term threats. See previous discussion for more information concerning the broader Slight Risk across the Mid to upper Mississippi Valley and in the Central Appalachians and Mid-Atlantic below. ..Thornton/Mosier.. 05/15/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/ ...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley... Recent satellite imagery shows an upper low over SD, with a negatively tilted shortwave trough moving into the Mid MO Valley. Surface analysis places an occluded surface low associated with this system over southeast ND, with an occluded front extending southeastward to a triple point over far southeast SD. A cold front extends south-southeastward from this front across far western IA and into far northeast MO before arcing more southwestward across far western MO and more southwestward across western OK. A warm front extends easterward from this triple point across southern MN and then more southeastward across southwest WI and northern IL. These boundaries, including the occluded front, will all act in tandem with increasing large-scale forcing for ascent to force thunderstorm development this afternoon and evening. The ongoing storms from eastern SD into central MN are confirmation of the buoyancy sampled in the 12Z MPX sounding. Expectation is for instability to build across the region as heating and low-level moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first from the eastern Dakotas into MN, the occluded front as it shifts northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther southeast along the warm front across WI. Storms that develop in the vicinity of the occluded front will likely have elevated structures, with large hail as the primary risk. Some isolated very large hail (i.e. greater than 2" in diameter) is possible. Farther southeast, the corridor along the warm front appears very favorable for supercells capable of all severe hazards, including very large hail, strong wind gusts, and tornadoes. A locally higher tornado potential may exist from central into southeastern WI from 18Z-22Z. Deeper mixing is anticipated farther south into northern IL, but the overall environment will still support robust, organized updrafts. There may be some trend initially for these storms to quickly become outflow dominant, but strengthening mid-level flow across the region after 21Z should aid in maintaining a more organized mode. Upscale growth into a organized MCS appears probable after 00Z, with the potential for significant-severe gusts as this line moves eastward in southern Lower MI. The threat for damaging gusts and isolated hail will persist throughout the night across Lower MI and the middle/upper OH Valley. ...Ozarks into the TN Valley... Additional thunderstorm development is anticipated this afternoon across AR as a cold front pushes eastward across the region. Moderate to strong flow aloft should allow for storms to move off this boundary quickly into a strongly buoyant airmass downstream. Warm air aloft could limit overall storm longevity during the afternoon/early evening, but the warm/dry mid-levels are conducive for producing strong outflows capable of damaging gusts. Whether or not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN. Additional thunderstorms are possible during the evening and overnight in the wake of the front. Persistent steep mid-level lapse rates and strong shear will support large hail with some of these storms. ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Thu May 15 2025 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ...SUMMARY... Severe thunderstorms are expected across parts of the upper Mississippi River Valley and Great Lakes this afternoon and evening. Tornadoes, some of which could be strong, and very large hail and damaging winds will be possible. Severe thunderstorms are also expected through the lower Ohio River Valley, Ozarks and in parts of the Mid-Atlantic. ...20z Update... Only minor changes were made to trim probabilities behind ongoing convective activity with this update. The Enhanced Risk across the Midwest remains unchanged. Thunderstorm activity has been ongoing in this region, with reports of a couple of tornadoes in western Minnesota. Expect thunderstorm activity to continue to strengthen in this area. See MCD#791 for more information on the short term threats. See previous discussion for more information concerning the broader Slight Risk across the Mid to upper Mississippi Valley and in the Central Appalachians and Mid-Atlantic below. ..Thornton/Mosier.. 05/15/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/ ...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley... Recent satellite imagery shows an upper low over SD, with a negatively tilted shortwave trough moving into the Mid MO Valley. Surface analysis places an occluded surface low associated with this system over southeast ND, with an occluded front extending southeastward to a triple point over far southeast SD. A cold front extends south-southeastward from this front across far western IA and into far northeast MO before arcing more southwestward across far western MO and more southwestward across western OK. A warm front extends easterward from this triple point across southern MN and then more southeastward across southwest WI and northern IL. These boundaries, including the occluded front, will all act in tandem with increasing large-scale forcing for ascent to force thunderstorm development this afternoon and evening. The ongoing storms from eastern SD into central MN are confirmation of the buoyancy sampled in the 12Z MPX sounding. Expectation is for instability to build across the region as heating and low-level moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first from the eastern Dakotas into MN, the occluded front as it shifts northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther southeast along the warm front across WI. Storms that develop in the vicinity of the occluded front will likely have elevated structures, with large hail as the primary risk. Some isolated very large hail (i.e. greater than 2" in diameter) is possible. Farther southeast, the corridor along the warm front appears very favorable for supercells capable of all severe hazards, including very large hail, strong wind gusts, and tornadoes. A locally higher tornado potential may exist from central into southeastern WI from 18Z-22Z. Deeper mixing is anticipated farther south into northern IL, but the overall environment will still support robust, organized updrafts. There may be some trend initially for these storms to quickly become outflow dominant, but strengthening mid-level flow across the region after 21Z should aid in maintaining a more organized mode. Upscale growth into a organized MCS appears probable after 00Z, with the potential for significant-severe gusts as this line moves eastward in southern Lower MI. The threat for damaging gusts and isolated hail will persist throughout the night across Lower MI and the middle/upper OH Valley. ...Ozarks into the TN Valley... Additional thunderstorm development is anticipated this afternoon across AR as a cold front pushes eastward across the region. Moderate to strong flow aloft should allow for storms to move off this boundary quickly into a strongly buoyant airmass downstream. Warm air aloft could limit overall storm longevity during the afternoon/early evening, but the warm/dry mid-levels are conducive for producing strong outflows capable of damaging gusts. Whether or not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN. Additional thunderstorms are possible during the evening and overnight in the wake of the front. Persistent steep mid-level lapse rates and strong shear will support large hail with some of these storms. ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0227 PM CDT Thu May 15 2025 Valid 152000Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ...SUMMARY... Severe thunderstorms are expected across parts of the upper Mississippi River Valley and Great Lakes this afternoon and evening. Tornadoes, some of which could be strong, and very large hail and damaging winds will be possible. Severe thunderstorms are also expected through the lower Ohio River Valley, Ozarks and in parts of the Mid-Atlantic. ...20z Update... Only minor changes were made to trim probabilities behind ongoing convective activity with this update. The Enhanced Risk across the Midwest remains unchanged. Thunderstorm activity has been ongoing in this region, with reports of a couple of tornadoes in western Minnesota. Expect thunderstorm activity to continue to strengthen in this area. See MCD#791 for more information on the short term threats. See previous discussion for more information concerning the broader Slight Risk across the Mid to upper Mississippi Valley and in the Central Appalachians and Mid-Atlantic below. ..Thornton/Mosier.. 05/15/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/ ...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley... Recent satellite imagery shows an upper low over SD, with a negatively tilted shortwave trough moving into the Mid MO Valley. Surface analysis places an occluded surface low associated with this system over southeast ND, with an occluded front extending southeastward to a triple point over far southeast SD. A cold front extends south-southeastward from this front across far western IA and into far northeast MO before arcing more southwestward across far western MO and more southwestward across western OK. A warm front extends easterward from this triple point across southern MN and then more southeastward across southwest WI and northern IL. These boundaries, including the occluded front, will all act in tandem with increasing large-scale forcing for ascent to force thunderstorm development this afternoon and evening. The ongoing storms from eastern SD into central MN are confirmation of the buoyancy sampled in the 12Z MPX sounding. Expectation is for instability to build across the region as heating and low-level moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first from the eastern Dakotas into MN, the occluded front as it shifts northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther southeast along the warm front across WI. Storms that develop in the vicinity of the occluded front will likely have elevated structures, with large hail as the primary risk. Some isolated very large hail (i.e. greater than 2" in diameter) is possible. Farther southeast, the corridor along the warm front appears very favorable for supercells capable of all severe hazards, including very large hail, strong wind gusts, and tornadoes. A locally higher tornado potential may exist from central into southeastern WI from 18Z-22Z. Deeper mixing is anticipated farther south into northern IL, but the overall environment will still support robust, organized updrafts. There may be some trend initially for these storms to quickly become outflow dominant, but strengthening mid-level flow across the region after 21Z should aid in maintaining a more organized mode. Upscale growth into a organized MCS appears probable after 00Z, with the potential for significant-severe gusts as this line moves eastward in southern Lower MI. The threat for damaging gusts and isolated hail will persist throughout the night across Lower MI and the middle/upper OH Valley. ...Ozarks into the TN Valley... Additional thunderstorm development is anticipated this afternoon across AR as a cold front pushes eastward across the region. Moderate to strong flow aloft should allow for storms to move off this boundary quickly into a strongly buoyant airmass downstream. Warm air aloft could limit overall storm longevity during the afternoon/early evening, but the warm/dry mid-levels are conducive for producing strong outflows capable of damaging gusts. Whether or not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN. Additional thunderstorms are possible during the evening and overnight in the wake of the front. Persistent steep mid-level lapse rates and strong shear will support large hail with some of these storms. ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Thu May 15 2025 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN PLAINS INTO ARKANSAS...AND OVER PARTS OF THE MID-ATLANTIC AND NORTHEAST... ...SUMMARY... Severe thunderstorms are possible Saturday across parts of the Mid Atlantic and Northeast, and across parts of the southeastern Great Plains to Lower Mississippi Valley. ...Synopsis... An upper cyclone and attendant shortwave trough over the upper Great Lakes to the TN Valley will shift east on Saturday, becoming positioned from NY to offshore the Mid-Atlantic coast by Sunday morning. Meanwhile, an upper trough will dig across the western U.S. while upper ridging develops over much of the Plains. A belt of strong westerly flow associated with the eastern upper trough will overspread much of eastern U.S., while a sub-tropical jet streak moves across the southern Plain into the Lower MS Valley. At the surface, a cold front will surge east across the Ohio Valley through early afternoon, and the Mid-Atlantic and Northeast during the evening/overnight. The southwest extent of this surface boundary will extend from the Lower OH Valley into central OK Saturday morning. The boundary may sag southward across portions of the TN Valley, while the Plains portion of the boundary lifts northward into KS and southern MO during the evening/overnight. Meanwhile, a surface dryline will extend south/southwest from near western OK to the TX Big Bend vicinity. ...Southern Plains to Lower MS Valley... The building upper ridge over the Plains will likely suppress convection across portions of the region as an EML will be difficult to overcome without stronger large-scale ascent/height falls. However, low-level convergence along the dryline amid persistent low-level warm advection and forecast shortwave perturbations migrating through the upper ridge from the southern Rockies into the Red River vicinity may aid in isolated to widely scattered storm development during the afternoon. A very moist airmass will be in place (upper 60s/low 70s F dewpoints) beneath 7.5-8.5 C/km midlevel lapse rates. This will result in strong instability across the warm sector (MLCAPE greater than 2500 J/kg). Furthermore, supercell wind profiles are apparent in forecast soundings, with curved low-level hodographs become elongated/straight above 2-3 km. Any discrete cells that develop will pose a risk for large to very large hail. If sufficient storm coverage occurs, some clustering could result in upscale developing into an MCS moving across the ArkLaTex vicinity and into the Lower MS Valley during the evening/nighttime hours. If this occurs, a risk for damaging gusts will increase. ...Southeast... Convection may be ongoing/weakening across portions of MS/AL/GA/SC/NC Saturday morning. It is unclear how this activity may evolve, but an outflow boundary will likely extend across portions of MS/AL/GA. Given a very moist and unstable airmass by afternoon some redevelopment of thunderstorms is possible. Forcing for ascent will be nebulous across the Deep South, so coverage may remain sparse. Nevertheless, any storm that develops could produce strong gusts or hail. ...NC/VA into the Northeast... Convection may be ongoing across portions of NC/VA Saturday morning but likely will be weakening as outflow is expected to be surging across the Piedmont. It is unclear if redevelopment may occur ahead of the surface cold front during the afternoon/evening. While a very moist and unstable airmass will reside across the region, large-scale ascent will remain weak and focused further north toward the Northeast. If storms can develop, a risk for large hail and damaging gusts will be possible. Additional storms are expected to develop with northward extent into the Northeast beneath the upper low and ahead of the surface cold front. While boundary layer moisture will be more modest with northward extent, cool temperatures aloft will foster modest destabilization. Isolated to widely scattered storms will pose a risk for hail and gusty winds through early evening. ..Leitman.. 05/15/2025 Read more