Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0929 AM CST Sun Nov 10 2024 Valid 101700Z - 111200Z Elevated conditions are likely from northern New Jersey and far northeast Pennsylvania to southern New England late this morning into the afternoon before showers arrive as a warm front lifts northward through the Northeast. Locally elevated conditions are already developing in parts of Upstate New York and northeast Pennsylvania ahead of the increasing cloud cover and showers. While marginally elevated conditions are expected in a relatively narrow temporal window, the ongoing drought and record high fire danger in the region led to the issuance. ..Nauslar.. 11/10/2024 .PREV DISCUSSION... /ISSUED 1218 AM CST Sun Nov 10 2024/ ...Synopsis... Fire weather concerns are expected to be minimal today across the CONUS. A trough will traverse the Great Lakes region, with cooler and wetter conditions extending from the Upper Midwest into the Ohio River Valley and up to the Northeast. Cooler post-frontal conditions will extend across much of the Plains. Some briefly Elevated conditions are possible in the Northeast ahead of the approaching front, but wetting rainfall will be expected by the afternoon. Lingering dry conditions will be possible across southern California, but generally light winds will keep fire concerns low. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0626 AM CST Sun Nov 10 2024 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... General upper-air pattern deamplification is expected over most of the CONUS through the period, except over: 1. The West Coast (height falls ahead of an approaching, high-amplitude synoptic trough) and 2. The Great Lakes (height falls preceding the ejection of the cyclone now centered over northwest IA). The formerly cut-off/larger cyclone is rejoining the prevailing westerlies, and will accelerate eastward and weaken over the Great Lakes. This will happen as a strong shortwave trough -- evident in moisture-channel imagery over eastern/southern AB -- digs east-southeastward toward Lake Superior by 12Z tomorrow, while forming a closed or nearly closed 500-mb low. Meanwhile, Tropical Storm Rafael continues to weaken as its low- level center and deep convection get more displaced from each other, per NHC discussions. The circulation is forecast to continue weakening, as the low-level vortex loops around the central/west- central Gulf today, then shift southwestward thereafter. Refer to NHC advisories for latest forecast track/intensity of Rafael. In between those features, a plume of moist low-level air, cooling northward at the surface and aloft, will support isolated to scattered thunderstorms, near and east of an occluded/cold frontal zone drawn at 11Z from southern IL across westernmost portions of KY/TN, western MS, central/southwestern LA, and TX coastal waters. ...Gulf Coast to Ohio Valley... Overall severe potential will be limited by lack of stronger shear in the south (closer to the coast) where low-level theta-e is largest, and lack of surface-based instability in the north. Some model soundings suggest that surface-based parcels and marginal deep shear (effective-shear magnitudes in the 30-40-kt range) may overlap this afternoon over portions of the Tennessee Valley to lower Ohio Valley. While this will need to be monitored, lack of backing in low-level flow will limit both convergence and hodograph size, amid weak deep-layer lapse rates and potentially messy convective mode. At this time, the severe threat appears too low and conditional for an outlook area. ..Edwards/Bentley.. 11/10/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0626 AM CST Sun Nov 10 2024 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... General upper-air pattern deamplification is expected over most of the CONUS through the period, except over: 1. The West Coast (height falls ahead of an approaching, high-amplitude synoptic trough) and 2. The Great Lakes (height falls preceding the ejection of the cyclone now centered over northwest IA). The formerly cut-off/larger cyclone is rejoining the prevailing westerlies, and will accelerate eastward and weaken over the Great Lakes. This will happen as a strong shortwave trough -- evident in moisture-channel imagery over eastern/southern AB -- digs east-southeastward toward Lake Superior by 12Z tomorrow, while forming a closed or nearly closed 500-mb low. Meanwhile, Tropical Storm Rafael continues to weaken as its low- level center and deep convection get more displaced from each other, per NHC discussions. The circulation is forecast to continue weakening, as the low-level vortex loops around the central/west- central Gulf today, then shift southwestward thereafter. Refer to NHC advisories for latest forecast track/intensity of Rafael. In between those features, a plume of moist low-level air, cooling northward at the surface and aloft, will support isolated to scattered thunderstorms, near and east of an occluded/cold frontal zone drawn at 11Z from southern IL across westernmost portions of KY/TN, western MS, central/southwestern LA, and TX coastal waters. ...Gulf Coast to Ohio Valley... Overall severe potential will be limited by lack of stronger shear in the south (closer to the coast) where low-level theta-e is largest, and lack of surface-based instability in the north. Some model soundings suggest that surface-based parcels and marginal deep shear (effective-shear magnitudes in the 30-40-kt range) may overlap this afternoon over portions of the Tennessee Valley to lower Ohio Valley. While this will need to be monitored, lack of backing in low-level flow will limit both convergence and hodograph size, amid weak deep-layer lapse rates and potentially messy convective mode. At this time, the severe threat appears too low and conditional for an outlook area. ..Edwards/Bentley.. 11/10/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0626 AM CST Sun Nov 10 2024 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... General upper-air pattern deamplification is expected over most of the CONUS through the period, except over: 1. The West Coast (height falls ahead of an approaching, high-amplitude synoptic trough) and 2. The Great Lakes (height falls preceding the ejection of the cyclone now centered over northwest IA). The formerly cut-off/larger cyclone is rejoining the prevailing westerlies, and will accelerate eastward and weaken over the Great Lakes. This will happen as a strong shortwave trough -- evident in moisture-channel imagery over eastern/southern AB -- digs east-southeastward toward Lake Superior by 12Z tomorrow, while forming a closed or nearly closed 500-mb low. Meanwhile, Tropical Storm Rafael continues to weaken as its low- level center and deep convection get more displaced from each other, per NHC discussions. The circulation is forecast to continue weakening, as the low-level vortex loops around the central/west- central Gulf today, then shift southwestward thereafter. Refer to NHC advisories for latest forecast track/intensity of Rafael. In between those features, a plume of moist low-level air, cooling northward at the surface and aloft, will support isolated to scattered thunderstorms, near and east of an occluded/cold frontal zone drawn at 11Z from southern IL across westernmost portions of KY/TN, western MS, central/southwestern LA, and TX coastal waters. ...Gulf Coast to Ohio Valley... Overall severe potential will be limited by lack of stronger shear in the south (closer to the coast) where low-level theta-e is largest, and lack of surface-based instability in the north. Some model soundings suggest that surface-based parcels and marginal deep shear (effective-shear magnitudes in the 30-40-kt range) may overlap this afternoon over portions of the Tennessee Valley to lower Ohio Valley. While this will need to be monitored, lack of backing in low-level flow will limit both convergence and hodograph size, amid weak deep-layer lapse rates and potentially messy convective mode. At this time, the severe threat appears too low and conditional for an outlook area. ..Edwards/Bentley.. 11/10/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0626 AM CST Sun Nov 10 2024 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... General upper-air pattern deamplification is expected over most of the CONUS through the period, except over: 1. The West Coast (height falls ahead of an approaching, high-amplitude synoptic trough) and 2. The Great Lakes (height falls preceding the ejection of the cyclone now centered over northwest IA). The formerly cut-off/larger cyclone is rejoining the prevailing westerlies, and will accelerate eastward and weaken over the Great Lakes. This will happen as a strong shortwave trough -- evident in moisture-channel imagery over eastern/southern AB -- digs east-southeastward toward Lake Superior by 12Z tomorrow, while forming a closed or nearly closed 500-mb low. Meanwhile, Tropical Storm Rafael continues to weaken as its low- level center and deep convection get more displaced from each other, per NHC discussions. The circulation is forecast to continue weakening, as the low-level vortex loops around the central/west- central Gulf today, then shift southwestward thereafter. Refer to NHC advisories for latest forecast track/intensity of Rafael. In between those features, a plume of moist low-level air, cooling northward at the surface and aloft, will support isolated to scattered thunderstorms, near and east of an occluded/cold frontal zone drawn at 11Z from southern IL across westernmost portions of KY/TN, western MS, central/southwestern LA, and TX coastal waters. ...Gulf Coast to Ohio Valley... Overall severe potential will be limited by lack of stronger shear in the south (closer to the coast) where low-level theta-e is largest, and lack of surface-based instability in the north. Some model soundings suggest that surface-based parcels and marginal deep shear (effective-shear magnitudes in the 30-40-kt range) may overlap this afternoon over portions of the Tennessee Valley to lower Ohio Valley. While this will need to be monitored, lack of backing in low-level flow will limit both convergence and hodograph size, amid weak deep-layer lapse rates and potentially messy convective mode. At this time, the severe threat appears too low and conditional for an outlook area. ..Edwards/Bentley.. 11/10/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0626 AM CST Sun Nov 10 2024 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... General upper-air pattern deamplification is expected over most of the CONUS through the period, except over: 1. The West Coast (height falls ahead of an approaching, high-amplitude synoptic trough) and 2. The Great Lakes (height falls preceding the ejection of the cyclone now centered over northwest IA). The formerly cut-off/larger cyclone is rejoining the prevailing westerlies, and will accelerate eastward and weaken over the Great Lakes. This will happen as a strong shortwave trough -- evident in moisture-channel imagery over eastern/southern AB -- digs east-southeastward toward Lake Superior by 12Z tomorrow, while forming a closed or nearly closed 500-mb low. Meanwhile, Tropical Storm Rafael continues to weaken as its low- level center and deep convection get more displaced from each other, per NHC discussions. The circulation is forecast to continue weakening, as the low-level vortex loops around the central/west- central Gulf today, then shift southwestward thereafter. Refer to NHC advisories for latest forecast track/intensity of Rafael. In between those features, a plume of moist low-level air, cooling northward at the surface and aloft, will support isolated to scattered thunderstorms, near and east of an occluded/cold frontal zone drawn at 11Z from southern IL across westernmost portions of KY/TN, western MS, central/southwestern LA, and TX coastal waters. ...Gulf Coast to Ohio Valley... Overall severe potential will be limited by lack of stronger shear in the south (closer to the coast) where low-level theta-e is largest, and lack of surface-based instability in the north. Some model soundings suggest that surface-based parcels and marginal deep shear (effective-shear magnitudes in the 30-40-kt range) may overlap this afternoon over portions of the Tennessee Valley to lower Ohio Valley. While this will need to be monitored, lack of backing in low-level flow will limit both convergence and hodograph size, amid weak deep-layer lapse rates and potentially messy convective mode. At this time, the severe threat appears too low and conditional for an outlook area. ..Edwards/Bentley.. 11/10/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0626 AM CST Sun Nov 10 2024 Valid 101300Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... General upper-air pattern deamplification is expected over most of the CONUS through the period, except over: 1. The West Coast (height falls ahead of an approaching, high-amplitude synoptic trough) and 2. The Great Lakes (height falls preceding the ejection of the cyclone now centered over northwest IA). The formerly cut-off/larger cyclone is rejoining the prevailing westerlies, and will accelerate eastward and weaken over the Great Lakes. This will happen as a strong shortwave trough -- evident in moisture-channel imagery over eastern/southern AB -- digs east-southeastward toward Lake Superior by 12Z tomorrow, while forming a closed or nearly closed 500-mb low. Meanwhile, Tropical Storm Rafael continues to weaken as its low- level center and deep convection get more displaced from each other, per NHC discussions. The circulation is forecast to continue weakening, as the low-level vortex loops around the central/west- central Gulf today, then shift southwestward thereafter. Refer to NHC advisories for latest forecast track/intensity of Rafael. In between those features, a plume of moist low-level air, cooling northward at the surface and aloft, will support isolated to scattered thunderstorms, near and east of an occluded/cold frontal zone drawn at 11Z from southern IL across westernmost portions of KY/TN, western MS, central/southwestern LA, and TX coastal waters. ...Gulf Coast to Ohio Valley... Overall severe potential will be limited by lack of stronger shear in the south (closer to the coast) where low-level theta-e is largest, and lack of surface-based instability in the north. Some model soundings suggest that surface-based parcels and marginal deep shear (effective-shear magnitudes in the 30-40-kt range) may overlap this afternoon over portions of the Tennessee Valley to lower Ohio Valley. While this will need to be monitored, lack of backing in low-level flow will limit both convergence and hodograph size, amid weak deep-layer lapse rates and potentially messy convective mode. At this time, the severe threat appears too low and conditional for an outlook area. ..Edwards/Bentley.. 11/10/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0324 AM CST Sun Nov 10 2024 Valid 131200Z - 181200Z ...DISCUSSION... Predictability concerns that are evident on D3/Tuesday appear to affect the extended period. Non-GEFS/GFS models support a slower/southward evolution of a shortwave trough across the central states into the East on D4-5/Wednesday-Thursday. The 00Z deterministic ECMWF/UKMET are quite similar with this scenario. While the surface cyclone reflection may be weak, rich Gulf moisture coupled with an increase in low-level flow may be sufficient for at least a low-probability severe threat centered on the Lower MS Valley to the northeast Gulf Coast/southern Deep South. Late week, there continues to be above-average agreement with a positive-tilt longwave trough developing from the Canadian Prairies to off the southern CA coast. Despite typical predictability concerns with the handling of embedded shortwave impulses, the primary impactful difference is with the degree of moisture return across the Great Plains. Non-GEFS/GFS models have trended towards poorer-quality return flow in the wake of the leading shortwave trough on D4-5 and subsequent continental air mass intrusion into the Gulf. As such, despite SPC and NSSL GEFS-based ML guidance depicting 5-15 percent severe probabilities next weekend, other models seemingly suggest a 5 percent or less threat for now. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0324 AM CST Sun Nov 10 2024 Valid 131200Z - 181200Z ...DISCUSSION... Predictability concerns that are evident on D3/Tuesday appear to affect the extended period. Non-GEFS/GFS models support a slower/southward evolution of a shortwave trough across the central states into the East on D4-5/Wednesday-Thursday. The 00Z deterministic ECMWF/UKMET are quite similar with this scenario. While the surface cyclone reflection may be weak, rich Gulf moisture coupled with an increase in low-level flow may be sufficient for at least a low-probability severe threat centered on the Lower MS Valley to the northeast Gulf Coast/southern Deep South. Late week, there continues to be above-average agreement with a positive-tilt longwave trough developing from the Canadian Prairies to off the southern CA coast. Despite typical predictability concerns with the handling of embedded shortwave impulses, the primary impactful difference is with the degree of moisture return across the Great Plains. Non-GEFS/GFS models have trended towards poorer-quality return flow in the wake of the leading shortwave trough on D4-5 and subsequent continental air mass intrusion into the Gulf. As such, despite SPC and NSSL GEFS-based ML guidance depicting 5-15 percent severe probabilities next weekend, other models seemingly suggest a 5 percent or less threat for now. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0324 AM CST Sun Nov 10 2024 Valid 131200Z - 181200Z ...DISCUSSION... Predictability concerns that are evident on D3/Tuesday appear to affect the extended period. Non-GEFS/GFS models support a slower/southward evolution of a shortwave trough across the central states into the East on D4-5/Wednesday-Thursday. The 00Z deterministic ECMWF/UKMET are quite similar with this scenario. While the surface cyclone reflection may be weak, rich Gulf moisture coupled with an increase in low-level flow may be sufficient for at least a low-probability severe threat centered on the Lower MS Valley to the northeast Gulf Coast/southern Deep South. Late week, there continues to be above-average agreement with a positive-tilt longwave trough developing from the Canadian Prairies to off the southern CA coast. Despite typical predictability concerns with the handling of embedded shortwave impulses, the primary impactful difference is with the degree of moisture return across the Great Plains. Non-GEFS/GFS models have trended towards poorer-quality return flow in the wake of the leading shortwave trough on D4-5 and subsequent continental air mass intrusion into the Gulf. As such, despite SPC and NSSL GEFS-based ML guidance depicting 5-15 percent severe probabilities next weekend, other models seemingly suggest a 5 percent or less threat for now. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0324 AM CST Sun Nov 10 2024 Valid 131200Z - 181200Z ...DISCUSSION... Predictability concerns that are evident on D3/Tuesday appear to affect the extended period. Non-GEFS/GFS models support a slower/southward evolution of a shortwave trough across the central states into the East on D4-5/Wednesday-Thursday. The 00Z deterministic ECMWF/UKMET are quite similar with this scenario. While the surface cyclone reflection may be weak, rich Gulf moisture coupled with an increase in low-level flow may be sufficient for at least a low-probability severe threat centered on the Lower MS Valley to the northeast Gulf Coast/southern Deep South. Late week, there continues to be above-average agreement with a positive-tilt longwave trough developing from the Canadian Prairies to off the southern CA coast. Despite typical predictability concerns with the handling of embedded shortwave impulses, the primary impactful difference is with the degree of moisture return across the Great Plains. Non-GEFS/GFS models have trended towards poorer-quality return flow in the wake of the leading shortwave trough on D4-5 and subsequent continental air mass intrusion into the Gulf. As such, despite SPC and NSSL GEFS-based ML guidance depicting 5-15 percent severe probabilities next weekend, other models seemingly suggest a 5 percent or less threat for now. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0324 AM CST Sun Nov 10 2024 Valid 131200Z - 181200Z ...DISCUSSION... Predictability concerns that are evident on D3/Tuesday appear to affect the extended period. Non-GEFS/GFS models support a slower/southward evolution of a shortwave trough across the central states into the East on D4-5/Wednesday-Thursday. The 00Z deterministic ECMWF/UKMET are quite similar with this scenario. While the surface cyclone reflection may be weak, rich Gulf moisture coupled with an increase in low-level flow may be sufficient for at least a low-probability severe threat centered on the Lower MS Valley to the northeast Gulf Coast/southern Deep South. Late week, there continues to be above-average agreement with a positive-tilt longwave trough developing from the Canadian Prairies to off the southern CA coast. Despite typical predictability concerns with the handling of embedded shortwave impulses, the primary impactful difference is with the degree of moisture return across the Great Plains. Non-GEFS/GFS models have trended towards poorer-quality return flow in the wake of the leading shortwave trough on D4-5 and subsequent continental air mass intrusion into the Gulf. As such, despite SPC and NSSL GEFS-based ML guidance depicting 5-15 percent severe probabilities next weekend, other models seemingly suggest a 5 percent or less threat for now. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0324 AM CST Sun Nov 10 2024 Valid 131200Z - 181200Z ...DISCUSSION... Predictability concerns that are evident on D3/Tuesday appear to affect the extended period. Non-GEFS/GFS models support a slower/southward evolution of a shortwave trough across the central states into the East on D4-5/Wednesday-Thursday. The 00Z deterministic ECMWF/UKMET are quite similar with this scenario. While the surface cyclone reflection may be weak, rich Gulf moisture coupled with an increase in low-level flow may be sufficient for at least a low-probability severe threat centered on the Lower MS Valley to the northeast Gulf Coast/southern Deep South. Late week, there continues to be above-average agreement with a positive-tilt longwave trough developing from the Canadian Prairies to off the southern CA coast. Despite typical predictability concerns with the handling of embedded shortwave impulses, the primary impactful difference is with the degree of moisture return across the Great Plains. Non-GEFS/GFS models have trended towards poorer-quality return flow in the wake of the leading shortwave trough on D4-5 and subsequent continental air mass intrusion into the Gulf. As such, despite SPC and NSSL GEFS-based ML guidance depicting 5-15 percent severe probabilities next weekend, other models seemingly suggest a 5 percent or less threat for now. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CST Sun Nov 10 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A PART OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail is possible across a portion of the southern High Plains on Tuesday evening. ...Southern High Plains vicinity... A zonal upper flow regime over the southern states will buckle as a full-latitude trough progresses across the West and likely reaches the northern Great Plains to southern High Plains by 12Z Wednesday. Guidance differs with the evolution of individual shortwave impulses embedded within the broad trough. Non-NCEP guidance prefers amplification of the primary impulse within the basal portion of the trough. This would result in pronounced mid-level height falls overspreading the southern High Plains Tuesday evening/night. Low-level moisture quality will be lacking, owing to the continued presence of TC Rafael in the western Gulf. Modified moisture return will emanate northward from northeast Mexico. A plume of low to mid 50s surface dew points should reach the TX Panhandle by late day. This may yield a narrow ribbon of meager/weak buoyancy (MLCAPE around 500 J/kg), ahead of a sharpening surface trough. Confidence is low in whether surface-based storms will become sustained prior to sunset, given the limited buoyancy and rather dry mid-levels within the west-southwesterly flow regime. More probable convective development is expected during the evening as large-scale ascent increases with approach of the trough and strengthening low-level warm theta-e advection. With favorable speed shear in the cloud-bearing layer, a few elevated supercells may form with a threat for hail. Severe hail magnitudes should be confined to the early period of sustained-storm activity, but small hail could persist east-northeast Tuesday night. ..Grams.. 11/10/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CST Sun Nov 10 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A PART OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail is possible across a portion of the southern High Plains on Tuesday evening. ...Southern High Plains vicinity... A zonal upper flow regime over the southern states will buckle as a full-latitude trough progresses across the West and likely reaches the northern Great Plains to southern High Plains by 12Z Wednesday. Guidance differs with the evolution of individual shortwave impulses embedded within the broad trough. Non-NCEP guidance prefers amplification of the primary impulse within the basal portion of the trough. This would result in pronounced mid-level height falls overspreading the southern High Plains Tuesday evening/night. Low-level moisture quality will be lacking, owing to the continued presence of TC Rafael in the western Gulf. Modified moisture return will emanate northward from northeast Mexico. A plume of low to mid 50s surface dew points should reach the TX Panhandle by late day. This may yield a narrow ribbon of meager/weak buoyancy (MLCAPE around 500 J/kg), ahead of a sharpening surface trough. Confidence is low in whether surface-based storms will become sustained prior to sunset, given the limited buoyancy and rather dry mid-levels within the west-southwesterly flow regime. More probable convective development is expected during the evening as large-scale ascent increases with approach of the trough and strengthening low-level warm theta-e advection. With favorable speed shear in the cloud-bearing layer, a few elevated supercells may form with a threat for hail. Severe hail magnitudes should be confined to the early period of sustained-storm activity, but small hail could persist east-northeast Tuesday night. ..Grams.. 11/10/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CST Sun Nov 10 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A PART OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail is possible across a portion of the southern High Plains on Tuesday evening. ...Southern High Plains vicinity... A zonal upper flow regime over the southern states will buckle as a full-latitude trough progresses across the West and likely reaches the northern Great Plains to southern High Plains by 12Z Wednesday. Guidance differs with the evolution of individual shortwave impulses embedded within the broad trough. Non-NCEP guidance prefers amplification of the primary impulse within the basal portion of the trough. This would result in pronounced mid-level height falls overspreading the southern High Plains Tuesday evening/night. Low-level moisture quality will be lacking, owing to the continued presence of TC Rafael in the western Gulf. Modified moisture return will emanate northward from northeast Mexico. A plume of low to mid 50s surface dew points should reach the TX Panhandle by late day. This may yield a narrow ribbon of meager/weak buoyancy (MLCAPE around 500 J/kg), ahead of a sharpening surface trough. Confidence is low in whether surface-based storms will become sustained prior to sunset, given the limited buoyancy and rather dry mid-levels within the west-southwesterly flow regime. More probable convective development is expected during the evening as large-scale ascent increases with approach of the trough and strengthening low-level warm theta-e advection. With favorable speed shear in the cloud-bearing layer, a few elevated supercells may form with a threat for hail. Severe hail magnitudes should be confined to the early period of sustained-storm activity, but small hail could persist east-northeast Tuesday night. ..Grams.. 11/10/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CST Sun Nov 10 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A PART OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail is possible across a portion of the southern High Plains on Tuesday evening. ...Southern High Plains vicinity... A zonal upper flow regime over the southern states will buckle as a full-latitude trough progresses across the West and likely reaches the northern Great Plains to southern High Plains by 12Z Wednesday. Guidance differs with the evolution of individual shortwave impulses embedded within the broad trough. Non-NCEP guidance prefers amplification of the primary impulse within the basal portion of the trough. This would result in pronounced mid-level height falls overspreading the southern High Plains Tuesday evening/night. Low-level moisture quality will be lacking, owing to the continued presence of TC Rafael in the western Gulf. Modified moisture return will emanate northward from northeast Mexico. A plume of low to mid 50s surface dew points should reach the TX Panhandle by late day. This may yield a narrow ribbon of meager/weak buoyancy (MLCAPE around 500 J/kg), ahead of a sharpening surface trough. Confidence is low in whether surface-based storms will become sustained prior to sunset, given the limited buoyancy and rather dry mid-levels within the west-southwesterly flow regime. More probable convective development is expected during the evening as large-scale ascent increases with approach of the trough and strengthening low-level warm theta-e advection. With favorable speed shear in the cloud-bearing layer, a few elevated supercells may form with a threat for hail. Severe hail magnitudes should be confined to the early period of sustained-storm activity, but small hail could persist east-northeast Tuesday night. ..Grams.. 11/10/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CST Sun Nov 10 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A PART OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail is possible across a portion of the southern High Plains on Tuesday evening. ...Southern High Plains vicinity... A zonal upper flow regime over the southern states will buckle as a full-latitude trough progresses across the West and likely reaches the northern Great Plains to southern High Plains by 12Z Wednesday. Guidance differs with the evolution of individual shortwave impulses embedded within the broad trough. Non-NCEP guidance prefers amplification of the primary impulse within the basal portion of the trough. This would result in pronounced mid-level height falls overspreading the southern High Plains Tuesday evening/night. Low-level moisture quality will be lacking, owing to the continued presence of TC Rafael in the western Gulf. Modified moisture return will emanate northward from northeast Mexico. A plume of low to mid 50s surface dew points should reach the TX Panhandle by late day. This may yield a narrow ribbon of meager/weak buoyancy (MLCAPE around 500 J/kg), ahead of a sharpening surface trough. Confidence is low in whether surface-based storms will become sustained prior to sunset, given the limited buoyancy and rather dry mid-levels within the west-southwesterly flow regime. More probable convective development is expected during the evening as large-scale ascent increases with approach of the trough and strengthening low-level warm theta-e advection. With favorable speed shear in the cloud-bearing layer, a few elevated supercells may form with a threat for hail. Severe hail magnitudes should be confined to the early period of sustained-storm activity, but small hail could persist east-northeast Tuesday night. ..Grams.. 11/10/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CST Sun Nov 10 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN A PART OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated severe hail is possible across a portion of the southern High Plains on Tuesday evening. ...Southern High Plains vicinity... A zonal upper flow regime over the southern states will buckle as a full-latitude trough progresses across the West and likely reaches the northern Great Plains to southern High Plains by 12Z Wednesday. Guidance differs with the evolution of individual shortwave impulses embedded within the broad trough. Non-NCEP guidance prefers amplification of the primary impulse within the basal portion of the trough. This would result in pronounced mid-level height falls overspreading the southern High Plains Tuesday evening/night. Low-level moisture quality will be lacking, owing to the continued presence of TC Rafael in the western Gulf. Modified moisture return will emanate northward from northeast Mexico. A plume of low to mid 50s surface dew points should reach the TX Panhandle by late day. This may yield a narrow ribbon of meager/weak buoyancy (MLCAPE around 500 J/kg), ahead of a sharpening surface trough. Confidence is low in whether surface-based storms will become sustained prior to sunset, given the limited buoyancy and rather dry mid-levels within the west-southwesterly flow regime. More probable convective development is expected during the evening as large-scale ascent increases with approach of the trough and strengthening low-level warm theta-e advection. With favorable speed shear in the cloud-bearing layer, a few elevated supercells may form with a threat for hail. Severe hail magnitudes should be confined to the early period of sustained-storm activity, but small hail could persist east-northeast Tuesday night. ..Grams.. 11/10/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 AM CST Sun Nov 10 2024 Valid 111200Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected Monday or Monday night. ...Southeast... Isolated, elevated thunderstorms may be ongoing across parts of the Carolina Coastal Plain. Weak tropospheric lapse rates will be a limiting factor to updraft intensity. Low-level flow will become increasingly veered during the day, yielding a predominately zonal flow regime. This should result in thunder potential shifting entirely offshore around midday. A few thunderstorms embedded within a corridor of slow-moving convection will be possible along a portion of the central Gulf Coast, before activity gradually wanes during the day. Isolated thunderstorms may also develop across a portion of south FL during the afternoon. ...Western WA/OR and northern CA... A leading shortwave trough and attendant surface cold front should move onshore Monday morning. In its wake, low to mid-level lapse rates will steepen amid meager buoyancy. An upstream shortwave impulse and persistent onshore low-level winds should support scattered, low-topped convection. Some of this will be sufficiently deep to foster sporadic lightning through Monday evening. Thunderstorm probabilities will diminish Monday night as the plume of steep mid-level lapse rates shifts farther inland. ..Grams.. 11/10/2024 Read more