Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Fri Jun 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY AND OVER THE FOUR CORNERS REGION... ...SUMMARY... Scattered strong to severe storms are expected from parts of the northern High Plains into the upper Mississippi Valley, mainly this afternoon and evening. Scattered strong/severe thunderstorms are also possible across the Four Corners vicinity. A few strong storms may occur from parts of the lower Great Lakes to southern New England. ...Northern High Plains... A shortwave trough will shift eastward from the Canadian Rockies toward Saskatchewan, with southeasterly low-level flow deep into Montana ahead of this shortwave trough. Relatively strong (40 kt) mid-level flow will develop across central Montana as the upper ridge flattens. Scattered robust convection should easily develop within a flow regime favorable for supercells. Forecast soundings, especially for central Montana, exhibit favorable deep-layer shear with strong buoyancy and relatively low cloud bases. Scattered supercells should evolve by early afternoon then propagate southeastward along the instability axis toward eastern/south-central Montana through early evening. Very large hail and gusty winds are expected along with some tornado risk. ...Middle Missouri Valley/Siouxland to Upper Mississippi Valley... Scattered thunderstorms persist this morning regionally in vicinity of the convectively modified frontal zone. A mid-level impulse over Colorado/southeast Wyoming this morning will reach the Siouxland by late afternoon and early evening, all while a south-southwesterly low-level jet markedly intensifies after sunset. Strong diurnal heating south of the boundary will ease CINH across the warm sector and scattered storms are expected to develop and intensify. Updrafts may initially develop along the cool side of the boundary but with time surface-based storms are expected. Hail, wind, and perhaps a couple tornadoes can be expected with supercells occurring near the front. ...Four Corners Region... A seasonally high PW plume will advance into the Four Corners region as a low-latitude shortwave trough over southern California/Nevada ejects over the Great Basin, strengthening mid-level flow across southern Utah into southwestern Colorado. Sustained multicells and some supercells should develop along the southern fringe of this shortwave trough, where strong shear will support organized longer-lived updrafts. Large hail and strong/gusty winds can be expected, and some tornado risk may exist as well. ...Lower Great Lakes to southern New England... Strong boundary-layer heating will once again occur across the lower Great Lakes region into portions of southern New England, with a southward-shifting front focusing scattered convection into early/mid-afternoon. Within a moderately unstable environment, localized wind damage will be the primary concern with the strongest storms his afternoon through around sunset. ..Guyer/Mosier.. 06/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Fri Jun 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY AND OVER THE FOUR CORNERS REGION... ...SUMMARY... Scattered strong to severe storms are expected from parts of the northern High Plains into the upper Mississippi Valley, mainly this afternoon and evening. Scattered strong/severe thunderstorms are also possible across the Four Corners vicinity. A few strong storms may occur from parts of the lower Great Lakes to southern New England. ...Northern High Plains... A shortwave trough will shift eastward from the Canadian Rockies toward Saskatchewan, with southeasterly low-level flow deep into Montana ahead of this shortwave trough. Relatively strong (40 kt) mid-level flow will develop across central Montana as the upper ridge flattens. Scattered robust convection should easily develop within a flow regime favorable for supercells. Forecast soundings, especially for central Montana, exhibit favorable deep-layer shear with strong buoyancy and relatively low cloud bases. Scattered supercells should evolve by early afternoon then propagate southeastward along the instability axis toward eastern/south-central Montana through early evening. Very large hail and gusty winds are expected along with some tornado risk. ...Middle Missouri Valley/Siouxland to Upper Mississippi Valley... Scattered thunderstorms persist this morning regionally in vicinity of the convectively modified frontal zone. A mid-level impulse over Colorado/southeast Wyoming this morning will reach the Siouxland by late afternoon and early evening, all while a south-southwesterly low-level jet markedly intensifies after sunset. Strong diurnal heating south of the boundary will ease CINH across the warm sector and scattered storms are expected to develop and intensify. Updrafts may initially develop along the cool side of the boundary but with time surface-based storms are expected. Hail, wind, and perhaps a couple tornadoes can be expected with supercells occurring near the front. ...Four Corners Region... A seasonally high PW plume will advance into the Four Corners region as a low-latitude shortwave trough over southern California/Nevada ejects over the Great Basin, strengthening mid-level flow across southern Utah into southwestern Colorado. Sustained multicells and some supercells should develop along the southern fringe of this shortwave trough, where strong shear will support organized longer-lived updrafts. Large hail and strong/gusty winds can be expected, and some tornado risk may exist as well. ...Lower Great Lakes to southern New England... Strong boundary-layer heating will once again occur across the lower Great Lakes region into portions of southern New England, with a southward-shifting front focusing scattered convection into early/mid-afternoon. Within a moderately unstable environment, localized wind damage will be the primary concern with the strongest storms his afternoon through around sunset. ..Guyer/Mosier.. 06/21/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Fri Jun 21 2024 Valid 211300Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY AND OVER THE FOUR CORNERS REGION... ...SUMMARY... Scattered strong to severe storms are expected from parts of the northern High Plains into the upper Mississippi Valley, mainly this afternoon and evening. Scattered strong/severe thunderstorms are also possible across the Four Corners vicinity. A few strong storms may occur from parts of the lower Great Lakes to southern New England. ...Northern High Plains... A shortwave trough will shift eastward from the Canadian Rockies toward Saskatchewan, with southeasterly low-level flow deep into Montana ahead of this shortwave trough. Relatively strong (40 kt) mid-level flow will develop across central Montana as the upper ridge flattens. Scattered robust convection should easily develop within a flow regime favorable for supercells. Forecast soundings, especially for central Montana, exhibit favorable deep-layer shear with strong buoyancy and relatively low cloud bases. Scattered supercells should evolve by early afternoon then propagate southeastward along the instability axis toward eastern/south-central Montana through early evening. Very large hail and gusty winds are expected along with some tornado risk. ...Middle Missouri Valley/Siouxland to Upper Mississippi Valley... Scattered thunderstorms persist this morning regionally in vicinity of the convectively modified frontal zone. A mid-level impulse over Colorado/southeast Wyoming this morning will reach the Siouxland by late afternoon and early evening, all while a south-southwesterly low-level jet markedly intensifies after sunset. Strong diurnal heating south of the boundary will ease CINH across the warm sector and scattered storms are expected to develop and intensify. Updrafts may initially develop along the cool side of the boundary but with time surface-based storms are expected. Hail, wind, and perhaps a couple tornadoes can be expected with supercells occurring near the front. ...Four Corners Region... A seasonally high PW plume will advance into the Four Corners region as a low-latitude shortwave trough over southern California/Nevada ejects over the Great Basin, strengthening mid-level flow across southern Utah into southwestern Colorado. Sustained multicells and some supercells should develop along the southern fringe of this shortwave trough, where strong shear will support organized longer-lived updrafts. Large hail and strong/gusty winds can be expected, and some tornado risk may exist as well. ...Lower Great Lakes to southern New England... Strong boundary-layer heating will once again occur across the lower Great Lakes region into portions of southern New England, with a southward-shifting front focusing scattered convection into early/mid-afternoon. Within a moderately unstable environment, localized wind damage will be the primary concern with the strongest storms his afternoon through around sunset. ..Guyer/Mosier.. 06/21/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Fri Jun 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...D4/Monday: Northern Plains into the upper MS Valley/Great Lakes... A mid/upper-level shortwave trough and deepening surface low are forecast to move across parts of SK/MB on Monday. A surface trough will extend southward from the low into the northern Great Plains, with secondary surface low development possible across the Dakotas. A warm front will move northeastward somewhere from the eastern Dakotas into the upper MS Valley. Strong buoyancy is forecast to develop near and to the south/west of the warm front, with favorable deep-layer shear providing a conditionally favorable environment for severe thunderstorms. While some severe potential appears likely to evolve somewhere from the northern Plains into the upper MS Valley and/or upper Great Lakes, guidance varies regarding the position of the warm front, and also the southern extent of height falls and large-scale ascent attendant to the SK/MB shortwave trough. Much of the warm sector will likely remain capped, but severe storm development will be possible in closer proximity to the warm front and secondary surface low, which could potentially grow upscale and move southeastward along the instability gradient. Severe probabilities will likely be needed once confidence increases regarding the placement of the primary surface features. ...D5/Tuesday: Upper Midwest into the central/southern Plains... The shortwave trough that moves across parts of SK/MB on Monday is generally forecast to move east-southeastward on Tuesday across parts of ON and the upper Great Lakes. Model spread regarding the timing and track of this shortwave continues to increase at this time range, and the potential for MCS development on D4/Monday further reduces predictability regarding the severe threat on Tuesday. However, some severe-thunderstorm potential may evolve along a southeastward moving cold front from the Great Lakes/upper Midwest into parts of the central/southern Great Plains. ...D6/Wednesday - D8/Friday... Some threat for strong to severe thunderstorms could continue to accompany a southeastward-moving cold front on D6/Wednesday from the southern Plains into the Ohio Valley and Northeast, though predictability remains low regarding the details at this time range. By D7/Thursday into D8/Friday, extended-range guidance generally suggests the potential for a mid/upper-level shortwave trough to move across the northern Rockies toward the northern High Plains. However, model spread remains rather high regarding the evolution of moisture return and any increasing severe potential in association with this system. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Fri Jun 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...D4/Monday: Northern Plains into the upper MS Valley/Great Lakes... A mid/upper-level shortwave trough and deepening surface low are forecast to move across parts of SK/MB on Monday. A surface trough will extend southward from the low into the northern Great Plains, with secondary surface low development possible across the Dakotas. A warm front will move northeastward somewhere from the eastern Dakotas into the upper MS Valley. Strong buoyancy is forecast to develop near and to the south/west of the warm front, with favorable deep-layer shear providing a conditionally favorable environment for severe thunderstorms. While some severe potential appears likely to evolve somewhere from the northern Plains into the upper MS Valley and/or upper Great Lakes, guidance varies regarding the position of the warm front, and also the southern extent of height falls and large-scale ascent attendant to the SK/MB shortwave trough. Much of the warm sector will likely remain capped, but severe storm development will be possible in closer proximity to the warm front and secondary surface low, which could potentially grow upscale and move southeastward along the instability gradient. Severe probabilities will likely be needed once confidence increases regarding the placement of the primary surface features. ...D5/Tuesday: Upper Midwest into the central/southern Plains... The shortwave trough that moves across parts of SK/MB on Monday is generally forecast to move east-southeastward on Tuesday across parts of ON and the upper Great Lakes. Model spread regarding the timing and track of this shortwave continues to increase at this time range, and the potential for MCS development on D4/Monday further reduces predictability regarding the severe threat on Tuesday. However, some severe-thunderstorm potential may evolve along a southeastward moving cold front from the Great Lakes/upper Midwest into parts of the central/southern Great Plains. ...D6/Wednesday - D8/Friday... Some threat for strong to severe thunderstorms could continue to accompany a southeastward-moving cold front on D6/Wednesday from the southern Plains into the Ohio Valley and Northeast, though predictability remains low regarding the details at this time range. By D7/Thursday into D8/Friday, extended-range guidance generally suggests the potential for a mid/upper-level shortwave trough to move across the northern Rockies toward the northern High Plains. However, model spread remains rather high regarding the evolution of moisture return and any increasing severe potential in association with this system. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Fri Jun 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...D4/Monday: Northern Plains into the upper MS Valley/Great Lakes... A mid/upper-level shortwave trough and deepening surface low are forecast to move across parts of SK/MB on Monday. A surface trough will extend southward from the low into the northern Great Plains, with secondary surface low development possible across the Dakotas. A warm front will move northeastward somewhere from the eastern Dakotas into the upper MS Valley. Strong buoyancy is forecast to develop near and to the south/west of the warm front, with favorable deep-layer shear providing a conditionally favorable environment for severe thunderstorms. While some severe potential appears likely to evolve somewhere from the northern Plains into the upper MS Valley and/or upper Great Lakes, guidance varies regarding the position of the warm front, and also the southern extent of height falls and large-scale ascent attendant to the SK/MB shortwave trough. Much of the warm sector will likely remain capped, but severe storm development will be possible in closer proximity to the warm front and secondary surface low, which could potentially grow upscale and move southeastward along the instability gradient. Severe probabilities will likely be needed once confidence increases regarding the placement of the primary surface features. ...D5/Tuesday: Upper Midwest into the central/southern Plains... The shortwave trough that moves across parts of SK/MB on Monday is generally forecast to move east-southeastward on Tuesday across parts of ON and the upper Great Lakes. Model spread regarding the timing and track of this shortwave continues to increase at this time range, and the potential for MCS development on D4/Monday further reduces predictability regarding the severe threat on Tuesday. However, some severe-thunderstorm potential may evolve along a southeastward moving cold front from the Great Lakes/upper Midwest into parts of the central/southern Great Plains. ...D6/Wednesday - D8/Friday... Some threat for strong to severe thunderstorms could continue to accompany a southeastward-moving cold front on D6/Wednesday from the southern Plains into the Ohio Valley and Northeast, though predictability remains low regarding the details at this time range. By D7/Thursday into D8/Friday, extended-range guidance generally suggests the potential for a mid/upper-level shortwave trough to move across the northern Rockies toward the northern High Plains. However, model spread remains rather high regarding the evolution of moisture return and any increasing severe potential in association with this system. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Fri Jun 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...D4/Monday: Northern Plains into the upper MS Valley/Great Lakes... A mid/upper-level shortwave trough and deepening surface low are forecast to move across parts of SK/MB on Monday. A surface trough will extend southward from the low into the northern Great Plains, with secondary surface low development possible across the Dakotas. A warm front will move northeastward somewhere from the eastern Dakotas into the upper MS Valley. Strong buoyancy is forecast to develop near and to the south/west of the warm front, with favorable deep-layer shear providing a conditionally favorable environment for severe thunderstorms. While some severe potential appears likely to evolve somewhere from the northern Plains into the upper MS Valley and/or upper Great Lakes, guidance varies regarding the position of the warm front, and also the southern extent of height falls and large-scale ascent attendant to the SK/MB shortwave trough. Much of the warm sector will likely remain capped, but severe storm development will be possible in closer proximity to the warm front and secondary surface low, which could potentially grow upscale and move southeastward along the instability gradient. Severe probabilities will likely be needed once confidence increases regarding the placement of the primary surface features. ...D5/Tuesday: Upper Midwest into the central/southern Plains... The shortwave trough that moves across parts of SK/MB on Monday is generally forecast to move east-southeastward on Tuesday across parts of ON and the upper Great Lakes. Model spread regarding the timing and track of this shortwave continues to increase at this time range, and the potential for MCS development on D4/Monday further reduces predictability regarding the severe threat on Tuesday. However, some severe-thunderstorm potential may evolve along a southeastward moving cold front from the Great Lakes/upper Midwest into parts of the central/southern Great Plains. ...D6/Wednesday - D8/Friday... Some threat for strong to severe thunderstorms could continue to accompany a southeastward-moving cold front on D6/Wednesday from the southern Plains into the Ohio Valley and Northeast, though predictability remains low regarding the details at this time range. By D7/Thursday into D8/Friday, extended-range guidance generally suggests the potential for a mid/upper-level shortwave trough to move across the northern Rockies toward the northern High Plains. However, model spread remains rather high regarding the evolution of moisture return and any increasing severe potential in association with this system. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Fri Jun 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... ...D4/Monday: Northern Plains into the upper MS Valley/Great Lakes... A mid/upper-level shortwave trough and deepening surface low are forecast to move across parts of SK/MB on Monday. A surface trough will extend southward from the low into the northern Great Plains, with secondary surface low development possible across the Dakotas. A warm front will move northeastward somewhere from the eastern Dakotas into the upper MS Valley. Strong buoyancy is forecast to develop near and to the south/west of the warm front, with favorable deep-layer shear providing a conditionally favorable environment for severe thunderstorms. While some severe potential appears likely to evolve somewhere from the northern Plains into the upper MS Valley and/or upper Great Lakes, guidance varies regarding the position of the warm front, and also the southern extent of height falls and large-scale ascent attendant to the SK/MB shortwave trough. Much of the warm sector will likely remain capped, but severe storm development will be possible in closer proximity to the warm front and secondary surface low, which could potentially grow upscale and move southeastward along the instability gradient. Severe probabilities will likely be needed once confidence increases regarding the placement of the primary surface features. ...D5/Tuesday: Upper Midwest into the central/southern Plains... The shortwave trough that moves across parts of SK/MB on Monday is generally forecast to move east-southeastward on Tuesday across parts of ON and the upper Great Lakes. Model spread regarding the timing and track of this shortwave continues to increase at this time range, and the potential for MCS development on D4/Monday further reduces predictability regarding the severe threat on Tuesday. However, some severe-thunderstorm potential may evolve along a southeastward moving cold front from the Great Lakes/upper Midwest into parts of the central/southern Great Plains. ...D6/Wednesday - D8/Friday... Some threat for strong to severe thunderstorms could continue to accompany a southeastward-moving cold front on D6/Wednesday from the southern Plains into the Ohio Valley and Northeast, though predictability remains low regarding the details at this time range. By D7/Thursday into D8/Friday, extended-range guidance generally suggests the potential for a mid/upper-level shortwave trough to move across the northern Rockies toward the northern High Plains. However, model spread remains rather high regarding the evolution of moisture return and any increasing severe potential in association with this system. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Jun 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE OHIO VALLEY INTO THE NORTHEAST AND MID ATLANTIC... ...SUMMARY... Isolated severe thunderstorms will be possible on Sunday from parts of the Northeast and Mid Atlantic into the Ohio Valley. ...New England into the Ohio Valley... An upper trough is forecast to gradually amplify from the Great Lakes into the Northeast on Sunday. Guidance continues to vary with the timing and amplitude of embedded shortwaves within the larger-scale trough, but in general, one shortwave may move across New England during the day, while another moves southeast over the Great Lakes region during the afternoon/evening. A surface low is generally forecast to move from the upper Great Lakes into southern New England, as a trailing cold front moves through parts of the Northeast into the Ohio Valley. Depending on the potential influence of early-day convection, moderate buoyancy may develop along/ahead of the cold front, and thunderstorm development is expected as soon as late morning, with increasing coverage into the afternoon. Moderate deep-layer shear from the northern Mid Atlantic into southern New England will support potential for organized convection, and a few stronger cells/clusters may be capable of producing damaging wind and perhaps some hail. A tornado also will be possible, if a supercell or two can be sustained within moderately enhanced low-level flow/SRH. Farther southwest, modest northwesterly flow aloft could support a few strong to severe storms across the Ohio Valley during the afternoon/evening, with an attendant threat of isolated damaging wind and hail. ..Dean.. 06/21/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Jun 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE OHIO VALLEY INTO THE NORTHEAST AND MID ATLANTIC... ...SUMMARY... Isolated severe thunderstorms will be possible on Sunday from parts of the Northeast and Mid Atlantic into the Ohio Valley. ...New England into the Ohio Valley... An upper trough is forecast to gradually amplify from the Great Lakes into the Northeast on Sunday. Guidance continues to vary with the timing and amplitude of embedded shortwaves within the larger-scale trough, but in general, one shortwave may move across New England during the day, while another moves southeast over the Great Lakes region during the afternoon/evening. A surface low is generally forecast to move from the upper Great Lakes into southern New England, as a trailing cold front moves through parts of the Northeast into the Ohio Valley. Depending on the potential influence of early-day convection, moderate buoyancy may develop along/ahead of the cold front, and thunderstorm development is expected as soon as late morning, with increasing coverage into the afternoon. Moderate deep-layer shear from the northern Mid Atlantic into southern New England will support potential for organized convection, and a few stronger cells/clusters may be capable of producing damaging wind and perhaps some hail. A tornado also will be possible, if a supercell or two can be sustained within moderately enhanced low-level flow/SRH. Farther southwest, modest northwesterly flow aloft could support a few strong to severe storms across the Ohio Valley during the afternoon/evening, with an attendant threat of isolated damaging wind and hail. ..Dean.. 06/21/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Jun 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE OHIO VALLEY INTO THE NORTHEAST AND MID ATLANTIC... ...SUMMARY... Isolated severe thunderstorms will be possible on Sunday from parts of the Northeast and Mid Atlantic into the Ohio Valley. ...New England into the Ohio Valley... An upper trough is forecast to gradually amplify from the Great Lakes into the Northeast on Sunday. Guidance continues to vary with the timing and amplitude of embedded shortwaves within the larger-scale trough, but in general, one shortwave may move across New England during the day, while another moves southeast over the Great Lakes region during the afternoon/evening. A surface low is generally forecast to move from the upper Great Lakes into southern New England, as a trailing cold front moves through parts of the Northeast into the Ohio Valley. Depending on the potential influence of early-day convection, moderate buoyancy may develop along/ahead of the cold front, and thunderstorm development is expected as soon as late morning, with increasing coverage into the afternoon. Moderate deep-layer shear from the northern Mid Atlantic into southern New England will support potential for organized convection, and a few stronger cells/clusters may be capable of producing damaging wind and perhaps some hail. A tornado also will be possible, if a supercell or two can be sustained within moderately enhanced low-level flow/SRH. Farther southwest, modest northwesterly flow aloft could support a few strong to severe storms across the Ohio Valley during the afternoon/evening, with an attendant threat of isolated damaging wind and hail. ..Dean.. 06/21/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Jun 21 2024 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE OHIO VALLEY INTO THE NORTHEAST AND MID ATLANTIC... ...SUMMARY... Isolated severe thunderstorms will be possible on Sunday from parts of the Northeast and Mid Atlantic into the Ohio Valley. ...New England into the Ohio Valley... An upper trough is forecast to gradually amplify from the Great Lakes into the Northeast on Sunday. Guidance continues to vary with the timing and amplitude of embedded shortwaves within the larger-scale trough, but in general, one shortwave may move across New England during the day, while another moves southeast over the Great Lakes region during the afternoon/evening. A surface low is generally forecast to move from the upper Great Lakes into southern New England, as a trailing cold front moves through parts of the Northeast into the Ohio Valley. Depending on the potential influence of early-day convection, moderate buoyancy may develop along/ahead of the cold front, and thunderstorm development is expected as soon as late morning, with increasing coverage into the afternoon. Moderate deep-layer shear from the northern Mid Atlantic into southern New England will support potential for organized convection, and a few stronger cells/clusters may be capable of producing damaging wind and perhaps some hail. A tornado also will be possible, if a supercell or two can be sustained within moderately enhanced low-level flow/SRH. Farther southwest, modest northwesterly flow aloft could support a few strong to severe storms across the Ohio Valley during the afternoon/evening, with an attendant threat of isolated damaging wind and hail. ..Dean.. 06/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHERN MO...CENTRAL/EASTERN IA...SOUTHEAST MN...CENTRAL/SOUTHERN WI...NORTHWEST IL... ...SUMMARY... Severe storms will be possible across the upper Mississippi Valley and upper Midwest on Saturday. Damaging wind, isolated hail, and a tornado or two are all possible. ...East-central Great Plains into the upper Midwest... The Slight Risk has been shifted southward, based on the latest guidance regarding the likely position of the primary surface boundary during the afternoon and evening. A convectively enhanced shortwave trough is forecast to move across the upper Midwest on Saturday. In the wake of morning convection, moderate to locally strong buoyancy is expected to develop from eastern KS/southeast NE northeastward into parts of southern WI/northern IL, along/south of an outflow-reinforced front. Scattered thunderstorms are expected to develop along the front by late afternoon and spread eastward into the evening. Effective shear generally in the 30-40 kt range will support a few organized cells/clusters. Relatively strong heating and large PW will support strong/damaging gusts as the most likely hazard. Warm temperatures aloft and weak midlevel lapse rates should limit the hail threat, though isolated hail cannot be ruled out if any supercells can be sustained. A tornado or two will also be possible, in the presence of moderate low-level southwesterly flow and modestly enhanced SRH. Farther east, intensification of morning convection and/or afternoon redevelopment will be possible across parts of lower MI. While instability will be weaker compared to areas father west, somewhat enhanced low/midlevel flow will support a threat for isolated damaging wind and possibly a brief tornado. ...Parts of the Northeast... Widely scattered thunderstorms will be possible across parts of the Northeast during the afternoon and evening, within a warm, moderately unstable, and weakly capped environment along/south of a cold front draped across parts of New England. Modest midlevel west-southwesterly flow could support a few weakly organized cells/clusters capable of locally damaging wind. ...Parts of ND... A mid/upper-level shortwave trough is forecast to move across parts of SK/MB on Saturday, with some influence of this shortwave expected to extend into parts of ND. Isolated to widely scattered thunderstorm development will be possible during the afternoon/evening, with moderate buoyancy and sufficient deep-layer shear supporting potential for a few organized storms capable of isolated hail and strong/severe gusts. ..Dean.. 06/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHERN MO...CENTRAL/EASTERN IA...SOUTHEAST MN...CENTRAL/SOUTHERN WI...NORTHWEST IL... ...SUMMARY... Severe storms will be possible across the upper Mississippi Valley and upper Midwest on Saturday. Damaging wind, isolated hail, and a tornado or two are all possible. ...East-central Great Plains into the upper Midwest... The Slight Risk has been shifted southward, based on the latest guidance regarding the likely position of the primary surface boundary during the afternoon and evening. A convectively enhanced shortwave trough is forecast to move across the upper Midwest on Saturday. In the wake of morning convection, moderate to locally strong buoyancy is expected to develop from eastern KS/southeast NE northeastward into parts of southern WI/northern IL, along/south of an outflow-reinforced front. Scattered thunderstorms are expected to develop along the front by late afternoon and spread eastward into the evening. Effective shear generally in the 30-40 kt range will support a few organized cells/clusters. Relatively strong heating and large PW will support strong/damaging gusts as the most likely hazard. Warm temperatures aloft and weak midlevel lapse rates should limit the hail threat, though isolated hail cannot be ruled out if any supercells can be sustained. A tornado or two will also be possible, in the presence of moderate low-level southwesterly flow and modestly enhanced SRH. Farther east, intensification of morning convection and/or afternoon redevelopment will be possible across parts of lower MI. While instability will be weaker compared to areas father west, somewhat enhanced low/midlevel flow will support a threat for isolated damaging wind and possibly a brief tornado. ...Parts of the Northeast... Widely scattered thunderstorms will be possible across parts of the Northeast during the afternoon and evening, within a warm, moderately unstable, and weakly capped environment along/south of a cold front draped across parts of New England. Modest midlevel west-southwesterly flow could support a few weakly organized cells/clusters capable of locally damaging wind. ...Parts of ND... A mid/upper-level shortwave trough is forecast to move across parts of SK/MB on Saturday, with some influence of this shortwave expected to extend into parts of ND. Isolated to widely scattered thunderstorm development will be possible during the afternoon/evening, with moderate buoyancy and sufficient deep-layer shear supporting potential for a few organized storms capable of isolated hail and strong/severe gusts. ..Dean.. 06/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHERN MO...CENTRAL/EASTERN IA...SOUTHEAST MN...CENTRAL/SOUTHERN WI...NORTHWEST IL... ...SUMMARY... Severe storms will be possible across the upper Mississippi Valley and upper Midwest on Saturday. Damaging wind, isolated hail, and a tornado or two are all possible. ...East-central Great Plains into the upper Midwest... The Slight Risk has been shifted southward, based on the latest guidance regarding the likely position of the primary surface boundary during the afternoon and evening. A convectively enhanced shortwave trough is forecast to move across the upper Midwest on Saturday. In the wake of morning convection, moderate to locally strong buoyancy is expected to develop from eastern KS/southeast NE northeastward into parts of southern WI/northern IL, along/south of an outflow-reinforced front. Scattered thunderstorms are expected to develop along the front by late afternoon and spread eastward into the evening. Effective shear generally in the 30-40 kt range will support a few organized cells/clusters. Relatively strong heating and large PW will support strong/damaging gusts as the most likely hazard. Warm temperatures aloft and weak midlevel lapse rates should limit the hail threat, though isolated hail cannot be ruled out if any supercells can be sustained. A tornado or two will also be possible, in the presence of moderate low-level southwesterly flow and modestly enhanced SRH. Farther east, intensification of morning convection and/or afternoon redevelopment will be possible across parts of lower MI. While instability will be weaker compared to areas father west, somewhat enhanced low/midlevel flow will support a threat for isolated damaging wind and possibly a brief tornado. ...Parts of the Northeast... Widely scattered thunderstorms will be possible across parts of the Northeast during the afternoon and evening, within a warm, moderately unstable, and weakly capped environment along/south of a cold front draped across parts of New England. Modest midlevel west-southwesterly flow could support a few weakly organized cells/clusters capable of locally damaging wind. ...Parts of ND... A mid/upper-level shortwave trough is forecast to move across parts of SK/MB on Saturday, with some influence of this shortwave expected to extend into parts of ND. Isolated to widely scattered thunderstorm development will be possible during the afternoon/evening, with moderate buoyancy and sufficient deep-layer shear supporting potential for a few organized storms capable of isolated hail and strong/severe gusts. ..Dean.. 06/21/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHERN MO...CENTRAL/EASTERN IA...SOUTHEAST MN...CENTRAL/SOUTHERN WI...NORTHWEST IL... ...SUMMARY... Severe storms will be possible across the upper Mississippi Valley and upper Midwest on Saturday. Damaging wind, isolated hail, and a tornado or two are all possible. ...East-central Great Plains into the upper Midwest... The Slight Risk has been shifted southward, based on the latest guidance regarding the likely position of the primary surface boundary during the afternoon and evening. A convectively enhanced shortwave trough is forecast to move across the upper Midwest on Saturday. In the wake of morning convection, moderate to locally strong buoyancy is expected to develop from eastern KS/southeast NE northeastward into parts of southern WI/northern IL, along/south of an outflow-reinforced front. Scattered thunderstorms are expected to develop along the front by late afternoon and spread eastward into the evening. Effective shear generally in the 30-40 kt range will support a few organized cells/clusters. Relatively strong heating and large PW will support strong/damaging gusts as the most likely hazard. Warm temperatures aloft and weak midlevel lapse rates should limit the hail threat, though isolated hail cannot be ruled out if any supercells can be sustained. A tornado or two will also be possible, in the presence of moderate low-level southwesterly flow and modestly enhanced SRH. Farther east, intensification of morning convection and/or afternoon redevelopment will be possible across parts of lower MI. While instability will be weaker compared to areas father west, somewhat enhanced low/midlevel flow will support a threat for isolated damaging wind and possibly a brief tornado. ...Parts of the Northeast... Widely scattered thunderstorms will be possible across parts of the Northeast during the afternoon and evening, within a warm, moderately unstable, and weakly capped environment along/south of a cold front draped across parts of New England. Modest midlevel west-southwesterly flow could support a few weakly organized cells/clusters capable of locally damaging wind. ...Parts of ND... A mid/upper-level shortwave trough is forecast to move across parts of SK/MB on Saturday, with some influence of this shortwave expected to extend into parts of ND. Isolated to widely scattered thunderstorm development will be possible during the afternoon/evening, with moderate buoyancy and sufficient deep-layer shear supporting potential for a few organized storms capable of isolated hail and strong/severe gusts. ..Dean.. 06/21/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... For Saturday, upper-level ridging will gradually shift westward and the strongest mid-level winds will stay within the northern half of the CONUS. An upper-level shortwave will approach the Northwest late in the period. Surface winds will again be generally light across the Great Basin into the Northwest. While brief and locally elevated conditions may occur, highlights do not appear necessary at this time. ..Wendt.. 06/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... For Saturday, upper-level ridging will gradually shift westward and the strongest mid-level winds will stay within the northern half of the CONUS. An upper-level shortwave will approach the Northwest late in the period. Surface winds will again be generally light across the Great Basin into the Northwest. While brief and locally elevated conditions may occur, highlights do not appear necessary at this time. ..Wendt.. 06/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... For Saturday, upper-level ridging will gradually shift westward and the strongest mid-level winds will stay within the northern half of the CONUS. An upper-level shortwave will approach the Northwest late in the period. Surface winds will again be generally light across the Great Basin into the Northwest. While brief and locally elevated conditions may occur, highlights do not appear necessary at this time. ..Wendt.. 06/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Fri Jun 21 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... For Saturday, upper-level ridging will gradually shift westward and the strongest mid-level winds will stay within the northern half of the CONUS. An upper-level shortwave will approach the Northwest late in the period. Surface winds will again be generally light across the Great Basin into the Northwest. While brief and locally elevated conditions may occur, highlights do not appear necessary at this time. ..Wendt.. 06/21/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more