Aggregator

000
ABPZ20 KNHC 171723
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Tue Sep 17 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Reinhart

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1208 PM CDT Tue Sep 17 2024 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail are possible across a portion of the Great Plains during the late afternoon and evening on Wednesday. ...Great Plains... A stacked cyclone will slowly shift east/northeast from eastern MT to southern SK/MB on Wednesday into early Thursday. At the surface, a dryline will be oriented from the eastern Dakotas into western/central NE, then southward across western KS and into the OK/TX Panhandle vicinity. With time, a cold front will merge with this feature on the northern end across the Dakotas during the nighttime hours. Deep-layer south/southwesterly flow will remain somewhat enhanced across the northern/central Plains toward the Upper Midwest as the mid/upper trough shifts east. Around 30-35 kt effective shear magnitudes are forecast along the extent of the dryline. Meanwhile, surface dewpoints in the 60s will be maintained ahead of the surface boundary in a persistent southerly low-level warm advection regime. Midlevel temperatures are forecast to be somewhat warm, precluding steeper lapse rates. Nevertheless, 1000-2000 J/kg MLCAPE is expected, with the greatest instability expected near/north of the Mid-MO Valley. Weakening convection may be ongoing Wednesday morning in the vicinity of the Mid-MO valley, with areas of cloud cover extending northward into MN. Where stronger heating occurs, low-level convergence along the surface dryline and any remnant outflow boundaries may focus thunderstorm development during the afternoon. Large-scale ascent will be nebulous, with stronger forcing focused near/north of the international border. Instability and shear will decrease with southward extent into KS and the southern Plains. This will limit coverage and intensity of convection to some degree. Nevertheless, isolated strong to severe storms may pose a risk for locally damaging gusts and hail. Additional thunderstorms may develop overnight as the surface cold front overtakes the dryline from the far eastern Dakotas into MN. This activity will be driven by warm advection and likely be elevated. Severe potential currently appears low beyond the 03-06z time frame. ..Leitman.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Tue Sep 17 2024 Valid 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and isolated large hail should occur this afternoon and evening across much of the High Plains. Some of the wind gusts may be significant (75+ mph). ...High Plains and Central/Southern Rockies... Expansions have been made to the Slight and Enhanced Risks across the northern/central High Plains to account for latest trends in guidance and observations. The Marginal Risk has also been expanded westward to include more of western CO and western/central WY, where isolated strong to severe winds are already ongoing with high-based convection. A strong upper trough/low over the Great Basin will pivot east-northeastward across the northern/central Rockies through this evening. An associated 50-60 kt mid-level jet will move eastward across the central/southern Rockies this afternoon, and over parts of the adjacent High Plains through this evening. As large-scale ascent with the upper trough and mid-level jet overspreads these regions, a surface low is forecast to deepen over eastern MT through this evening, while another low also develops over the central High Plains. A surface trough will extend southward from the central High Plains low, and it should sharpen as it develops eastward across the central/southern High Plains through the day. Greater low-level moisture, characterized by generally mid 50s to low 60s surface dewpoints, will gradually increase today along/east of the surface trough, while remaining more limited across the higher terrain of the central/southern Rockies. Moderate instability should develop to the east of the surface trough across much of the High Plains through peak afternoon heating. Strengthening deep-layer shear with the approach of the mid-level jet will support organized convection, including some potential for initial supercells across the northern High Plains (eastern MT and vicinity). Related threat for large hail will exist with any of this more discrete convection. Otherwise, thunderstorms will continue to develop this afternoon over the central/southern Rockies while producing isolated strong to severe wind gusts in a weakly unstable but strongly sheared environment. This activity will eventually spread off the higher terrain and into the central/southern High Plains. Steepened low-level lapse rates with robust daytime heating, along with more limited/shallow low-level moisture along/west of the surface trough, will likely support a gradually increasing severe wind threat with the high-based convection spreading east-northeastward across the southern/central Rockies. As these clusters and linear segments encounter greater low-level moisture and related instability along/east of the surface trough across the High Plains late this afternoon into early evening, the threat for scattered to numerous severe wind gusts should increase. This may particularly be the case across parts of the central High Plains, where the best combination of steepened low-level lapse rates, moderate instability, moderate to strong deep-layer shear, and greatest linear convective signal exists in 12Z guidance. Some chance for isolated gusts of 75+ mph may also be realized across this region with the more intense clusters spreading east-northeastward in tandem with the mid-level jet. The threat for severe winds is expected to gradually decrease with eastward extent across the Plains this evening as convection encounters increasing MLCIN with nocturnal cooling of the boundary layer. ...Florida... A weak mid/upper-level low will remain centered over the Southeast today. Modest mid-level westerly flow will persist over FL on the southern periphery of the upper low. Scattered to numerous thunderstorms should develop later this afternoon along/south of a remnant front, and along the Atlantic Coast sea breeze. Even with daytime heating of a rather moist low-level airmass, poor mid-level lapse rates should temper updraft intensities to some extent, even as moderate instability develops. That said, the stronger cores may be capable of producing isolated strong to damaging winds, with 20-25 kt of deep-layer shear aiding in modest thunderstorm organization. Some adjustments have been made to the Marginal Risk across parts of the FL Peninsula, based on latest observational trends and 12Z guidance. ...Southeast Virginia/Northeast North Carolina... A weak convective band is ongoing across far northeast NC into southeast VA, on the northeast side of a mid/upper-level low over the Southeast. Occasional strong/gusty winds may occur with the more robust cores this afternoon as the convective band pivots further into southeast VA. Even so, weak instability, modest low/mid-level flow, and related weak shear should temper overall thunderstorm organization. Accordingly, severe wind potential should remain low. ..Gleason/Moore.. 09/17/2024 Read more