Severe Storms

WW 0438 Status Updates
STATUS REPORT ON WW 438 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SQUITIERI..06/20/24 ATTN...WFO...BOX...GYX...CAR...BTV...ALY... STATUS REPORT FOR WS 438 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MEC001-005-007-009-011-013-015-017-019-021-023-025-027-031- 202140- ME . MAINE COUNTIES INCLUDED ARE ANDROSCOGGIN CUMBERLAND FRANKLIN HANCOCK KENNEBEC KNOX LINCOLN OXFORD PENOBSCOT PISCATAQUIS SAGADAHOC SOMERSET WALDO YORK MAC009-011-017-027-202140- MA . MASSACHUSETTS COUNTIES INCLUDED ARE ESSEX FRANKLIN MIDDLESEX WORCESTER NHC001-003-005-007-009-011-013-015-017-019-202140- NH . NEW HAMPSHIRE COUNTIES INCLUDED ARE Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...THE FOUR CORNERS...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Storms may produce scattered damaging wind gusts over parts of the Northeast and New England mainly this afternoon. Scattered severe storms are also expected over parts of the north-central High Plains, the Four Corners, and southern Lower Michigan. ...20z outlook update discussion... The only changes made to the outlook are described below. Otherwise, no change was made to the previous outlook and forecast reasoning appears on track. ...Southern Lower Michigan... Surface boundary has become draped west to east across southern Lower MI with a reservoir of lower 70s deg F surface dewpoints immediately in the vicinity of the front. Surface streamline analysis indicates weak surface convergence and preferential storm development is expected along the boundary through the early evening. Strong to severe gusts (50-65 mph) capable of wind damage will be the primary hazard with the stronger water-laden downdrafts. The ongoing thunderstorm activity will likely slowly migrate east-southeast into southeast Lower MI towards early evening. ...Four Corners... The northwest periphery of seasonably high moisture will continue to support additional storm development through the early to mid evening across this region. The development of steep 0-3 km lapse rates and a wind profile promoting organized single cells/multicells and perhaps transient supercells, will foster a risk for severe gusts (60-75 mph) through the early to mid evening with the stronger microbursts. ...Northeast Colorado... Have expanded the Slight-Risk equivalent severe probabilities farther south-southwest to east of the Front Range north/northeast of Denver. Storms will move east of the higher terrain of the Front Range and potentially pose a risk for wind/hail with the stronger storms. ..Smith.. 06/20/2024 .PREV DISCUSSION... /ISSUED 1112 AM CDT Thu Jun 20 2024/ ...Eastern NY and New England... Visible satellite imagery shows strong daytime heating occurring across all of New England and parts of NY/PA. A well-defined MCV currently over eastern Lake Ontario will track eastward into this warm and very humid air mass (dewpoints in the low 70s), where afternoon MLCAPE values will exceed 2000 J/kg. Scattered to numerous thunderstorms are expected, with storms spreading eastward through the afternoon towards the coast of southern ME/NH/MA. Winds aloft are not particularly strong, suggest early activity may be rather disorganized. However, eventual congealing of outflow will likely result in locally damaging wind gusts. Hail will also be possible in the strongest cells. Please refer to MCD #1340 for further details. ...Central High Plains... Latest surface analysis shows south-southeasterly low-level winds across the NE Panhandle and southeast WY, where dewpoints are in the 50s and lower 60s. This will help maintain a moist/unstable air mass in the area, yielding afternoon MLCAPE values of around 1500 J/kg. Scattered thunderstorms are expected to form over southeast WY by 20z, where sufficient deep-layer shear and steep lapse rates will favor supercell structures capable of very large hail and perhaps a tornado. Storms will track eastward into the NE Panhandle and southern SD through the evening, with an increasing risk of damaging winds (possibly exceeding 65kt). ...Western CO... Moderately strong southwesterly low/mid-level flow is present today across western CO, where full heating and diurnal destabilization will occur. Morning models continue to show scattered or greater thunderstorms coverage this afternoon, in a deeply mixed environment. Several fast-moving high-based thunderstorms are expected, with a risk of locally severe winds in the stronger cores. Read more

MD 1344 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR EASTERN WYOMING AND WESTERN NEBRASKA
Mesoscale Discussion 1344 NWS Storm Prediction Center Norman OK 0143 PM CDT Thu Jun 20 2024 Areas affected...Eastern Wyoming and Western Nebraska Concerning...Severe potential...Watch likely Valid 201843Z - 202015Z Probability of Watch Issuance...80 percent SUMMARY...Eastern WY into W NE and SW SD are being considered for a WW this afternoon, as thunderstorms develop on the higher terrain and move east into substantial buoyancy and deep layer shear supportive of large hail and damaging winds. DISCUSSION...Thunderstorm coverage has increased over the last hour as convective temperatures have been reached over the higher terrain. This activity is expected to progress eastward into the richer moisture and MLCAPE > 1500 J/kg, underneath deep layer shear of 35-45 kts. Given the buoyancy and shear, a few supercells capable of 2-inch hail and 70 MPH winds are expected across the highlighted area this afternoon. The threat for tornadoes remains low due to high MLLCL heights, though a supercell encountering easterly surface winds in E WY and W NE could produce a brief tornado. Given the environment and storm coverage, WW issuance is anticipated by 19-20Z. ..Halbert/Lyons/Hart.. 06/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...UNR...BOU...CYS... LAT...LON 41490607 41970602 42590561 43250408 43390316 43470214 43440103 43400043 43040020 42620016 42110013 41650032 41160106 40900214 40900308 40900483 41010589 41490607 Read more

MD 1342 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN COLORADO AND THE FOUR CORNERS REGION
Mesoscale Discussion 1342 NWS Storm Prediction Center Norman OK 0109 PM CDT Thu Jun 20 2024 Areas affected...Western Colorado and the Four Corners Region Concerning...Severe potential...Watch unlikely Valid 201809Z - 202015Z Probability of Watch Issuance...20 percent SUMMARY...Convective coverage is expected to increase this afternoon as temperatures warm into the upper 70s and low-to-mid 80s across the higher terrain of the intermountian west. Scattered thunderstorms capable of isolated damaging wind gusts and hail are possible, but WW issuance is not expected at this time. DISCUSSION...Convection is increasing over portions of W CO, with coverage expected to expand into the Four Corners region later this afternoon as convective temperatures are reached ahead of an approaching upper level trough. Morning sounding observations from Grand Junction and Flagstaff suggest wind shear supportive of organized convection, with deep layer bulk shear values in the 55-60kt range, and 500-1000 J/kg SBCAPE present in the SPC mesoanalysis. However, high LCL heights and widespread convective coverage will result in outflow dominant storms and frequent storm interactions, limiting overall severe potential. Still, a few reports of hail and damaging winds can be expected with any stronger, organized convection that develops. Given overall uncertainty in convective organization, however, WW issuance is not expected at this time. ..Halbert/Lyons/Hart.. 06/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PUB...BOU...ABQ...GJT...FGZ...SLC... LAT...LON 40850643 40840601 40600565 39350548 38540535 37830554 37190681 36790747 36490806 36180867 35910917 35970982 36231026 36771060 37241077 37501062 37861030 38680995 39250950 39860847 40720716 40850643 Read more

MD 1343 CONCERNING SEVERE THUNDERSTORM WATCH 438... FOR NORTHEAST NY TO PARTS OF NEW ENGLAND
Mesoscale Discussion 1343 NWS Storm Prediction Center Norman OK 0130 PM CDT Thu Jun 20 2024 Areas affected...northeast NY to parts of New England Concerning...Severe Thunderstorm Watch 438... Valid 201830Z - 202000Z The severe weather threat for Severe Thunderstorm Watch 438 continues. SUMMARY...An isolated mixed wind/hail risk should transition to a scattered damaging wind threat as individual cells loosely congeal into an east-southeast moving cluster through late afternoon. DISCUSSION...Numerous single cell thunderstorms are ongoing from parts of central NY to western ME and northward into southeast ON and south QC. The more prominent activity will likely persist in association with a well-defined MCV over northeast NY. With this corridor just north of the peak buoyancy plume over the Hudson Valley, characterized by MLCAPE around 2500 J/kg, further intensification is expected over the next 2-3 hours. Recent VWP data from CXX and TYX confirm a belt of modestly enhanced 3-6 km AGL westerlies around 25-30 kts. This should serve to loosely organize a multicell cluster across VT/NH/southwest ME and perhaps part of MA later this afternoon. Recent HRRR runs have been consistent on this scenario with 12Z NSSL-MPAS guidance. With surface temperatures having already warmed through the mid 90s from eastern MA into southwest ME, these hot temperatures should boost severe wind gust potential, and may yield peak gusts into the 55-70 mph range. ..Grams.. 06/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...ALY... LAT...LON 44717359 44627019 44076946 42887057 42477113 42407146 42487221 43037399 43467477 44717359 Read more