Aggregator

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Sep 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ...SUMMARY... A few tornadoes are possible today from northern Florida to north-central Alabama. Scattered large hail and severe wind gusts (some significant) are expected across eastern Montana into western North Dakota this afternoon through early/mid-evening. ...Northern Great Plains including eastern MT/western ND... Have upgraded portions of eastern Montana and western North Dakota for a heightened/focused potential for severe storms capable of large hail and potentially significant-caliber severe wind gusts later this afternoon through around mid-evening. Strong-severe thunderstorms are expected, along and behind the front, as early as early/mid-afternoon, with the most probable severe potential arising from activity moving north-northeastward from northern Wyoming and far southern Montana. High-based supercells and multicells are possible, offering large hail and severe wind gusts. These storms may aggregate and grow upscale into one or two bowing clusters, racing north-northeastward accompanied by a swath of better-organized, potentially significant (65+ kt) gust potential. This scenario will be supported by trough-related cooling mid-level temperatures and steep low/mid-level rates atop a modestly moist boundary layer, as the exit region of a strong upper-level jet overspreads the region. MLCAPE of 500-1200 J/kg and 45-55 kt effective-shear magnitudes will support the severe potential including fast-moving and relatively long-lived storms into western North Dakota. The near-surface airmass over the central Dakotas should stabilize with time and eastward extent tonight, limiting duration and eastward shift of the threat. ...Southeast... Current Tropical Depression Francine is forecast to continue moving generally northward over Mississippi, and to lose definition as it interacts more closely with the mid/upper-level low. Associated deep-layer winds will continue to weaken, but low-level shear will remain favorable through most of the day, well to the east-southeast of its center. A destabilizing airmass along and south of the warm/marine front will support a continued, slow inland shift of supercell potential amid enlarged hodographs. The favorable environment will be bounded on the west by a dry slot and veering low-level flow, on the northeast by more stable air in heavy precip north of the front, and on the south by a gradual weakening of low-level winds and shear as the cyclone center pulls away and fills. In the favorable corridor, where inflow parcels are surface-based, expect effective SRH in the 200-500 m2/s2 range, very rich moisture, low LCL, and weak MLCINH. In the shorter term, a tornado threat may persist this afternoon across northern Florida, while potentially increasing later this afternoon through early evening near the warm front across southern into central Alabama. ..Guyer/Jirak.. 09/12/2024 Read more

Issued at 1500 UTC THU SEP 12 2024 566 WTPZ24 KNHC 121530 TCMEP4 TROPICAL DEPRESSION NINE-E FORECAST/ADVISORY NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092024 1500 UTC THU SEP 12 2024 TROPICAL DEPRESSION CENTER LOCATED NEAR 19.2N 107.6W AT 12/1500Z POSITION ACCURATE WITHIN 40 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 325 DEGREES AT 6 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 19.2N 107.6W AT 12/1500Z AT 12/1200Z CENTER WAS LOCATED NEAR 18.8N 107.4W FORECAST VALID 13/0000Z 20.4N 108.4W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 50NE 30SE 0SW 30NW. FORECAST VALID 13/1200Z 22.0N 109.5W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 60NE 40SE 30SW 30NW. FORECAST VALID 14/0000Z 23.5N 110.2W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 60NE 30SE 30SW 40NW. FORECAST VALID 14/1200Z 25.0N 110.1W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 60NE 30SE 30SW 40NW. FORECAST VALID 15/0000Z 26.1N 110.0W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 50NE 20SE 0SW 30NW. FORECAST VALID 15/1200Z 27.0N 110.2W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 30NE 0SE 0SW 20NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 125 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 16/1200Z 28.6N 111.2W...POST-TROP/INLAND MAX WIND 25 KT...GUSTS 35 KT. OUTLOOK VALID 17/1200Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 19.2N 107.6W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPEP4...AT 12/1800Z NEXT ADVISORY AT 12/2100Z $$ FORECASTER HAGEN

WW 0669 Status Updates
STATUS REPORT ON WW 669 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 2059 ..DEAN..09/12/24 ATTN...WFO...MOB...TAE... STATUS REPORT FOR WT 669 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ALC013-031-035-039-041-045-053-061-067-069-099-131-121640- AL . ALABAMA COUNTIES INCLUDED ARE BUTLER COFFEE CONECUH COVINGTON CRENSHAW DALE ESCAMBIA GENEVA HENRY HOUSTON MONROE WILCOX FLC005-013-033-037-045-059-063-077-091-113-129-131-133-121640- FL . FLORIDA COUNTIES INCLUDED ARE BAY CALHOUN ESCAMBIA FRANKLIN GULF HOLMES JACKSON LIBERTY OKALOOSA SANTA ROSA WAKULLA WALTON WASHINGTON GMZ633-634-635-636-655-730-750-752-755-121640- Read more

WW 0669 Status Updates
STATUS REPORT ON WW 669 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 2059 ..DEAN..09/12/24 ATTN...WFO...MOB...TAE... STATUS REPORT FOR WT 669 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ALC013-031-035-039-041-045-053-061-067-069-099-131-121640- AL . ALABAMA COUNTIES INCLUDED ARE BUTLER COFFEE CONECUH COVINGTON CRENSHAW DALE ESCAMBIA GENEVA HENRY HOUSTON MONROE WILCOX FLC005-013-033-037-045-059-063-077-091-113-129-131-133-121640- FL . FLORIDA COUNTIES INCLUDED ARE BAY CALHOUN ESCAMBIA FRANKLIN GULF HOLMES JACKSON LIBERTY OKALOOSA SANTA ROSA WAKULLA WALTON WASHINGTON GMZ633-634-635-636-655-730-750-752-755-121640- Read more

WW 0669 Status Updates
STATUS REPORT ON WW 669 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 2059 ..DEAN..09/12/24 ATTN...WFO...MOB...TAE... STATUS REPORT FOR WT 669 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ALC013-031-035-039-041-045-053-061-067-069-099-131-121640- AL . ALABAMA COUNTIES INCLUDED ARE BUTLER COFFEE CONECUH COVINGTON CRENSHAW DALE ESCAMBIA GENEVA HENRY HOUSTON MONROE WILCOX FLC005-013-033-037-045-059-063-077-091-113-129-131-133-121640- FL . FLORIDA COUNTIES INCLUDED ARE BAY CALHOUN ESCAMBIA FRANKLIN GULF HOLMES JACKSON LIBERTY OKALOOSA SANTA ROSA WAKULLA WALTON WASHINGTON GMZ633-634-635-636-655-730-750-752-755-121640- Read more

WW 669 TORNADO AL FL CW 121050Z - 121800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 669 NWS Storm Prediction Center Norman OK 550 AM CDT Thu Sep 12 2024 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southern Alabama Florida Panhandle Coastal Waters * Effective this Thursday morning and afternoon from 550 AM until 100 PM CDT. * Primary threats include... A few tornadoes possible SUMMARY...As Francine's center continues moving northward over MS and weakens further through midday (per NHC forecast), a slot of wind/moisture/instability fields favorable for supercells and a few tornadoes will shift slowly northward/inland as well. The tornado watch area is approximately along and 60 statute miles north and south of a line from 35 miles west southwest of Evergreen AL to 35 miles south southeast of Marianna FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...This tornado watch replaces tornado watch number 668. Watch number 668 will not be in effect after 550 AM CDT. AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 0 inches. Extreme turbulence and surface wind gusts to 50 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 16030. ...Edwards Read more

5-Day Uncertainty Track last updated Thu, 12 Sep 2024 15:00:19 GMT


Wind Speed Probabilities last updated Thu, 12 Sep 2024 15:34:50 GMT

Issued at 800 AM MST Thu Sep 12 2024 000 WTPZ44 KNHC 121459 TCDEP4 Tropical Depression Nine-E Discussion Number 1 NWS National Hurricane Center Miami FL EP092024 800 AM MST Thu Sep 12 2024 Geostationary satellite imagery indicates that the growing area of deep convection associated with the low pressure system off the coast of west-central Mexico has been quite persistent with increased banding noted over the past 6 to 12 h. The subjective intensity estimate from TAFB is T-2.0/30 kt, and on this basis, the system is upgraded to a 30-kt tropical depression. The initial motion is an uncertain northwest, or 325/6 kt. There is a fair amount of uncertainty in the initial position of the center, but it appears to be near the eastern edge of the convection, based on recent microwave imagery. A deep-layer trough located over the western United States will steer the cyclone toward the north-northwest over the next 24 to 36 h, bringing the system near the southern portion of Baja California Sur. After that time, the deep-layer trough is forecast to weaken, which should cause steering currents to weaken. This pattern will likely induce a slower motion toward the north, likely over the waters of the southern Gulf of California. The cyclone could approach the coast of northern Sinaloa or Sonora Saturday night into Sunday. The track forecast guidance is in good agreement for the first 48 h, but then starts to diverge a bit while the system is over the southern Gulf of California. The NHC track forecast is near the middle of the guidance envelope. Due to some uncertainty in the track beyond that time, coastal residents of the Mexican states of Sinaloa and Sonora should continue to monitor the progress of this system. Tropical Depression Nine-E is currently located within an environment of warm ocean waters, low to moderate vertical wind shear, and within a fairly moist low- to mid-level troposphere. However, very dry air is evident on water vapor imagery to the northwest of the cyclone. These conditions are unlikely to change before the cyclone reaches Baja California Sur, and the NHC forecast shows the system becoming a tropical storm later today. Land interaction with the peninsula should cause some temporary weakening. However, water temperatures in the Gulf of California are quite warm, so some restrengthening is possible after the cyclone emerges back over water. The NHC intensity forecast is near the higher end of the intensity guidance. Beyond 60 h, westerly wind shear is expected to increase while the cyclone moves into a drier environment. Even if the system is still over water at that time, the cyclone is likely to begin weakening. The GFS and ECMWF simulated satellite imagery products show the cyclone losing its convection around 72 h. The NHC forecast shows weakening at that time, with the system becoming a remnant low beyond 72 h. Key Messages: 1. Tropical Depression Nine-E will bring heavy rainfall to portions of western Mexico and southern Baja California through this weekend. This heavy rainfall will bring a risk of flash flooding and mudslides to portions of the area. 2. Tropical storm conditions are expected to begin in portions of the Baja California Sur on Friday, where Tropical Storm Warnings have been issued. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 19.2N 107.6W 30 KT 35 MPH 12H 13/0000Z 20.4N 108.4W 35 KT 40 MPH 24H 13/1200Z 22.0N 109.5W 40 KT 45 MPH 36H 14/0000Z 23.5N 110.2W 45 KT 50 MPH 48H 14/1200Z 25.0N 110.1W 45 KT 50 MPH 60H 15/0000Z 26.1N 110.0W 45 KT 50 MPH 72H 15/1200Z 27.0N 110.2W 35 KT 40 MPH 96H 16/1200Z 28.6N 111.2W 25 KT 30 MPH...POST-TROP/INLAND 120H 17/1200Z...DISSIPATED $$ Forecaster Hagen

Issued at 1500 UTC THU SEP 12 2024 000 FOPZ14 KNHC 121458 PWSEP4 TROPICAL DEPRESSION NINE-E WIND SPEED PROBABILITIES NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092024 1500 UTC THU SEP 12 2024 AT 1500Z THE CENTER OF TROPICAL DEPRESSION NINE-E WAS LOCATED NEAR LATITUDE 19.2 NORTH...LONGITUDE 107.6 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 30 KTS...35 MPH...55 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 12Z THU AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 12Z THU 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON PERIODS TO TO TO TO TO TO TO 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON 12Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT CABO SAN LUCAS 34 X 14(14) 24(38) 1(39) X(39) X(39) X(39) CABO SAN LUCAS 50 X 1( 1) 6( 7) X( 7) X( 7) X( 7) X( 7) SAN JOSE CABO 34 X 11(11) 25(36) 2(38) X(38) X(38) X(38) SAN JOSE CABO 50 X 1( 1) 5( 6) X( 6) X( 6) X( 6) X( 6) LA PAZ 34 X 2( 2) 17(19) 9(28) 2(30) X(30) X(30) LA PAZ 50 X X( X) 3( 3) 2( 5) X( 5) X( 5) X( 5) LORETO 34 X X( X) 2( 2) 3( 5) 3( 8) X( 8) X( 8) GUAYMAS 34 X X( X) 1( 1) X( 1) 3( 4) 1( 5) X( 5) HUATABAMPO 34 X X( X) X( X) 1( 1) 4( 5) X( 5) X( 5) LOS MOCHIS 34 X X( X) X( X) 2( 2) 3( 5) X( 5) X( 5) 20N 110W 34 1 2( 3) X( 3) X( 3) X( 3) X( 3) X( 3) $$ FORECASTER HAGEN