Aggregator

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

MD 0417 CONCERNING TORNADO WATCH 103... FOR PARTS OF THE FLORIDA PANHANDLE
Mesoscale Discussion 0417 NWS Storm Prediction Center Norman OK 0635 PM CDT Wed Apr 10 2024 Areas affected...parts of the Florida Panhandle Concerning...Tornado Watch 103... Valid 102335Z - 110130Z The severe weather threat for Tornado Watch 103 continues. SUMMARY...The risk for severe weather has become increasingly negligible, at least in the near term, but could increase once again later this evening across at least coastal portions of the Florida Panhandle around Apalachicola. While the remainder of Tornado Watch 103 may be allowed to expire at 9 PM EDT, trends will need to continue to be monitored for the possibility of a new severe weather watch later this evening. DISCUSSION...The initially strong and better organized cluster of storms has undergone considerable further weakening as it continues to progress through an environment characterized by stable near-surface lapse rates and less unstable low-level inflow across and inland of northeastern Gulf coastal areas. Outflow, trailing the forward propagating portion of the remnant convective system now progressing into the Apalachicola vicinity, has advanced 60-70 miles offshore of the western Florida Panhandle, but appears to have stalled in advance of a significant mid-level short wave still west of the lower Mississippi Valley. Renewed thunderstorm development is ongoing along and southwest of the stalling portion of the outflow, aided by forcing associated with strengthening low-level warm advection beneath increasingly difluent upper flow. It appears that this may increasingly acquire low-level inflow of moderately unstable air over the next few hours, with potential for further upscale growth and the evolution of another organizing convective convective cluster along the outflow boundary through mid/late evening. While the bulk of the strongest storms may remain offshore, it is possible that the risk for severe storms could increase again across coastal areas around Apalachicola later this evening. ..Kerr.. 04/10/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TAE...MOB... LAT...LON 30448747 30648657 30558558 29918513 29558590 29648715 29908786 30448747 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Wed Apr 10 2024 Valid 110100Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG PORTIONS OF THE NORTHEAST GULF COAST... ...SUMMARY... Isolated severe risk continues this evening along the northeast Gulf Coast. Locally damaging winds are the primary threat, though a tornado can not be ruled out. ...01z Update... Long-lived MCS that developed over the TX Coastal Plain early this morning has progressed along the Gulf Coast with the leading edge of this complex now over the eastern FL Panhandle. An embedded MCV is noted along the northern portion of this complex along the AL/GA border south of CSG. While the primary upper trough is approaching the lower MS Valley, and warm advection will remain strong across the southeastern US overnight, the ongoing MCS has overturned buoyancy inland. The strongest deep convection has now shifted offshore and will likely struggle to redevelop inland, to any appreciable intensity, overnight. For these reasons, only a small portion of the northeast Gulf Coast will remain in severe probabilities this evening. ..Darrow.. 04/11/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Wed Apr 10 2024 Valid 110100Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG PORTIONS OF THE NORTHEAST GULF COAST... ...SUMMARY... Isolated severe risk continues this evening along the northeast Gulf Coast. Locally damaging winds are the primary threat, though a tornado can not be ruled out. ...01z Update... Long-lived MCS that developed over the TX Coastal Plain early this morning has progressed along the Gulf Coast with the leading edge of this complex now over the eastern FL Panhandle. An embedded MCV is noted along the northern portion of this complex along the AL/GA border south of CSG. While the primary upper trough is approaching the lower MS Valley, and warm advection will remain strong across the southeastern US overnight, the ongoing MCS has overturned buoyancy inland. The strongest deep convection has now shifted offshore and will likely struggle to redevelop inland, to any appreciable intensity, overnight. For these reasons, only a small portion of the northeast Gulf Coast will remain in severe probabilities this evening. ..Darrow.. 04/11/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Wed Apr 10 2024 Valid 110100Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG PORTIONS OF THE NORTHEAST GULF COAST... ...SUMMARY... Isolated severe risk continues this evening along the northeast Gulf Coast. Locally damaging winds are the primary threat, though a tornado can not be ruled out. ...01z Update... Long-lived MCS that developed over the TX Coastal Plain early this morning has progressed along the Gulf Coast with the leading edge of this complex now over the eastern FL Panhandle. An embedded MCV is noted along the northern portion of this complex along the AL/GA border south of CSG. While the primary upper trough is approaching the lower MS Valley, and warm advection will remain strong across the southeastern US overnight, the ongoing MCS has overturned buoyancy inland. The strongest deep convection has now shifted offshore and will likely struggle to redevelop inland, to any appreciable intensity, overnight. For these reasons, only a small portion of the northeast Gulf Coast will remain in severe probabilities this evening. ..Darrow.. 04/11/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Wed Apr 10 2024 Valid 110100Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG PORTIONS OF THE NORTHEAST GULF COAST... ...SUMMARY... Isolated severe risk continues this evening along the northeast Gulf Coast. Locally damaging winds are the primary threat, though a tornado can not be ruled out. ...01z Update... Long-lived MCS that developed over the TX Coastal Plain early this morning has progressed along the Gulf Coast with the leading edge of this complex now over the eastern FL Panhandle. An embedded MCV is noted along the northern portion of this complex along the AL/GA border south of CSG. While the primary upper trough is approaching the lower MS Valley, and warm advection will remain strong across the southeastern US overnight, the ongoing MCS has overturned buoyancy inland. The strongest deep convection has now shifted offshore and will likely struggle to redevelop inland, to any appreciable intensity, overnight. For these reasons, only a small portion of the northeast Gulf Coast will remain in severe probabilities this evening. ..Darrow.. 04/11/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Wed Apr 10 2024 Valid 110100Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG PORTIONS OF THE NORTHEAST GULF COAST... ...SUMMARY... Isolated severe risk continues this evening along the northeast Gulf Coast. Locally damaging winds are the primary threat, though a tornado can not be ruled out. ...01z Update... Long-lived MCS that developed over the TX Coastal Plain early this morning has progressed along the Gulf Coast with the leading edge of this complex now over the eastern FL Panhandle. An embedded MCV is noted along the northern portion of this complex along the AL/GA border south of CSG. While the primary upper trough is approaching the lower MS Valley, and warm advection will remain strong across the southeastern US overnight, the ongoing MCS has overturned buoyancy inland. The strongest deep convection has now shifted offshore and will likely struggle to redevelop inland, to any appreciable intensity, overnight. For these reasons, only a small portion of the northeast Gulf Coast will remain in severe probabilities this evening. ..Darrow.. 04/11/2024 Read more

WW 0103 Status Updates
STATUS REPORT ON WW 103 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 WSW PFN TO 10 NNW PFN TO 25 SW MAI TO TLH. REMAINING VALID PORTION OF WW 103 MAY BE ALLOWED TO EXPIRE AT 11/01Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0417. ..KERR..04/11/24 ATTN...WFO...BMX...TAE... STATUS REPORT FOR WT 103 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS FLC005-013-037-045-077-129-133-110100- FL . FLORIDA COUNTIES INCLUDED ARE BAY CALHOUN FRANKLIN GULF LIBERTY WAKULLA WASHINGTON GMZ750-752-110100- CW . ADJACENT COASTAL WATERS INCLUDED ARE COASTAL WATERS FROM OKALOOSA-WALTON COUNTY LINE TO MEXICO BEACH OUT 20 NM COASTAL WATERS FROM MEXICO BEACH TO APALACHICOLA OUT 20 NM Read more

WW 103 TORNADO AL FL GA CW 101810Z - 110100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 103 NWS Storm Prediction Center Norman OK 110 PM CDT Wed Apr 10 2024 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Alabama Florida Panhandle Southwest Georgia Coastal Waters * Effective this Wednesday afternoon and evening from 110 PM until 800 PM CDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Scattered damaging winds likely with isolated significant gusts to 75 mph possible SUMMARY...A cluster of storms are expected to move into the region through mid/late afternoon, with the potential for damaging winds and a few tornadoes expected to increase and potentially persist through at least early/mid evening in some areas. The tornado watch area is approximately along and 60 statute miles east and west of a line from 40 miles north northeast of Dothan AL to 30 miles west southwest of Apalachicola FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). 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...CONTINUE...WW 102... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25040. ...Guyer Read more

MD 0417 CONCERNING TORNADO WATCH 103... FOR PARTS OF THE FLORIDA PANHANDLE
Mesoscale Discussion 0417 NWS Storm Prediction Center Norman OK 0635 PM CDT Wed Apr 10 2024 Areas affected...parts of the Florida Panhandle Concerning...Tornado Watch 103... Valid 102335Z - 110130Z The severe weather threat for Tornado Watch 103 continues. SUMMARY...The risk for severe weather has become increasingly negligible, at least in the near term, but could increase once again later this evening across at least coastal portions of the Florida Panhandle around Apalachicola. While the remainder of Tornado Watch 103 may be allowed to expire at 9 PM EDT, trends will need to continue to be monitored for the possibility of a new severe weather watch later this evening. DISCUSSION...The initially strong and better organized cluster of storms has undergone considerable further weakening as it continues to progress through an environment characterized by stable near-surface lapse rates and less unstable low-level inflow across and inland of northeastern Gulf coastal areas. Outflow, trailing the forward propagating portion of the remnant convective system now progressing into the Apalachicola vicinity, has advanced 60-70 miles offshore of the western Florida Panhandle, but appears to have stalled in advance of a significant mid-level short wave still west of the lower Mississippi Valley. Renewed thunderstorm development is ongoing along and southwest of the stalling portion of the outflow, aided by forcing associated with strengthening low-level warm advection beneath increasingly difluent upper flow. It appears that this may increasingly acquire low-level inflow of moderately unstable air over the next few hours, with potential for further upscale growth and the evolution of another organizing convective convective cluster along the outflow boundary through mid/late evening. While the bulk of the strongest storms may remain offshore, it is possible that the risk for severe storms could increase again across coastal areas around Apalachicola later this evening. ..Kerr.. 04/10/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TAE...MOB... LAT...LON 30448747 30648657 30558558 29918513 29558590 29648715 29908786 30448747 Read more

WW 0103 Status Updates
STATUS REPORT ON WW 103 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 S CEW TO 20 NW PFN TO 10 NE MAI TO 30 WSW MGR. ..KERR..04/10/24 ATTN...WFO...BMX...TAE... STATUS REPORT FOR WT 103 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS FLC005-013-037-039-045-063-073-077-129-133-110040- FL . FLORIDA COUNTIES INCLUDED ARE BAY CALHOUN FRANKLIN GADSDEN GULF JACKSON LEON LIBERTY WAKULLA WASHINGTON GAC087-131-253-110040- GA . GEORGIA COUNTIES INCLUDED ARE DECATUR GRADY SEMINOLE GMZ750-752-110040- CW . ADJACENT COASTAL WATERS INCLUDED ARE Read more

WW 103 TORNADO AL FL GA CW 101810Z - 110100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 103 NWS Storm Prediction Center Norman OK 110 PM CDT Wed Apr 10 2024 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Alabama Florida Panhandle Southwest Georgia Coastal Waters * Effective this Wednesday afternoon and evening from 110 PM until 800 PM CDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Scattered damaging winds likely with isolated significant gusts to 75 mph possible SUMMARY...A cluster of storms are expected to move into the region through mid/late afternoon, with the potential for damaging winds and a few tornadoes expected to increase and potentially persist through at least early/mid evening in some areas. The tornado watch area is approximately along and 60 statute miles east and west of a line from 40 miles north northeast of Dothan AL to 30 miles west southwest of Apalachicola FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). 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...CONTINUE...WW 102... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25040. ...Guyer Read more

No Mesoscale Discussions are in effect as of Wed Apr 10 23:02:03 UTC 2024.