SPC Sep 15, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

10 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Sep 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE HIGH PLAINS... ...SUMMARY... Strong to locally severe thunderstorms will be possible Tuesday across a large swath of the High Plains region, mainly from late afternoon into the evening. Severe gusts should be the primary hazard, though some hail may also be possible. ...High Plains... A mid/upper-level shortwave trough initially over the eastern Great Basin should take on a negative tilt as it advances towards the northern High Plains. Deep lee cyclogenesis is expected over northeast WY/southeast MT, with a warm front extending east-northeast of the low somewhere from eastern MT into the Dakotas during the afternoon and evening. This low will advance north towards the MT/SK border area by 12Z Wednesday. Large-scale ascent will be pronounced within this synoptic regime, with favorable upper-level difluence, mid-level height falls, and low-level convergence. However, weak buoyancy and modest mid-level lapse rates will characterize much of the environment to the south of the surface low and warm front. Aided by the subtropical moisture plume over the Southwest, morning convection near the Four Corners region may move across the higher terrain toward the High Plains, with additional terrain-driven development possible during the afternoon. High-based storms will progress into a well-mixed boundary layer that may initially be devoid of appreciable CAPE. This lack of greater buoyancy during the late afternoon to early evening (outside of areas north of the warm front) yields substantial uncertainty regarding the degree of storm organization into the lower elevations. But with scattered to widespread convection and increasingly extensive outflow expected with time, sporadic severe gusts may occur during the afternoon and evening. Somewhat more favorable low-level moisture and buoyancy may reside near/north of the warm front, from eastern MT into the western Dakotas. While stronger ascent and deep-layer flow may not impinge upon areas north of the front later in the forecast period, there will be some potential for organized convection to develop during the evening as the shortwave trough ejects northeastward. A couple of supercells and/or stronger clusters will be possible within this regime, with a threat of hail and isolated severe gusts. ...Four Corners region... Despite the unfavorable time of day, a few strong storms cannot be ruled out Tuesday morning across the Four Corners region into western CO/NM, in close proximity to the ejecting shortwave trough. Wind profiles will be quite favorable for organized convection, though it remains uncertain if sufficient buoyancy will be present to support any severe threat during the early part of the day. ...Eastern NC/VA... With uncertainty already relatively high regarding evolution of the currently developing offshore low into D2/Monday, confidence remains too low to delineate severe probabilities for D3/Tuesday. Slower and more aggressive ensemble members continue to suggest an adequate SRH/buoyancy combination for low-topped supercells may linger over eastern NC early in the period and shift into parts of eastern VA. However, the bulk of guidance still indicates a general weakening of the low-level wind field during the day. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

10 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Sep 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE HIGH PLAINS... ...SUMMARY... Strong to locally severe thunderstorms will be possible Tuesday across a large swath of the High Plains region, mainly from late afternoon into the evening. Severe gusts should be the primary hazard, though some hail may also be possible. ...High Plains... A mid/upper-level shortwave trough initially over the eastern Great Basin should take on a negative tilt as it advances towards the northern High Plains. Deep lee cyclogenesis is expected over northeast WY/southeast MT, with a warm front extending east-northeast of the low somewhere from eastern MT into the Dakotas during the afternoon and evening. This low will advance north towards the MT/SK border area by 12Z Wednesday. Large-scale ascent will be pronounced within this synoptic regime, with favorable upper-level difluence, mid-level height falls, and low-level convergence. However, weak buoyancy and modest mid-level lapse rates will characterize much of the environment to the south of the surface low and warm front. Aided by the subtropical moisture plume over the Southwest, morning convection near the Four Corners region may move across the higher terrain toward the High Plains, with additional terrain-driven development possible during the afternoon. High-based storms will progress into a well-mixed boundary layer that may initially be devoid of appreciable CAPE. This lack of greater buoyancy during the late afternoon to early evening (outside of areas north of the warm front) yields substantial uncertainty regarding the degree of storm organization into the lower elevations. But with scattered to widespread convection and increasingly extensive outflow expected with time, sporadic severe gusts may occur during the afternoon and evening. Somewhat more favorable low-level moisture and buoyancy may reside near/north of the warm front, from eastern MT into the western Dakotas. While stronger ascent and deep-layer flow may not impinge upon areas north of the front later in the forecast period, there will be some potential for organized convection to develop during the evening as the shortwave trough ejects northeastward. A couple of supercells and/or stronger clusters will be possible within this regime, with a threat of hail and isolated severe gusts. ...Four Corners region... Despite the unfavorable time of day, a few strong storms cannot be ruled out Tuesday morning across the Four Corners region into western CO/NM, in close proximity to the ejecting shortwave trough. Wind profiles will be quite favorable for organized convection, though it remains uncertain if sufficient buoyancy will be present to support any severe threat during the early part of the day. ...Eastern NC/VA... With uncertainty already relatively high regarding evolution of the currently developing offshore low into D2/Monday, confidence remains too low to delineate severe probabilities for D3/Tuesday. Slower and more aggressive ensemble members continue to suggest an adequate SRH/buoyancy combination for low-topped supercells may linger over eastern NC early in the period and shift into parts of eastern VA. However, the bulk of guidance still indicates a general weakening of the low-level wind field during the day. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

10 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Sep 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE HIGH PLAINS... ...SUMMARY... Strong to locally severe thunderstorms will be possible Tuesday across a large swath of the High Plains region, mainly from late afternoon into the evening. Severe gusts should be the primary hazard, though some hail may also be possible. ...High Plains... A mid/upper-level shortwave trough initially over the eastern Great Basin should take on a negative tilt as it advances towards the northern High Plains. Deep lee cyclogenesis is expected over northeast WY/southeast MT, with a warm front extending east-northeast of the low somewhere from eastern MT into the Dakotas during the afternoon and evening. This low will advance north towards the MT/SK border area by 12Z Wednesday. Large-scale ascent will be pronounced within this synoptic regime, with favorable upper-level difluence, mid-level height falls, and low-level convergence. However, weak buoyancy and modest mid-level lapse rates will characterize much of the environment to the south of the surface low and warm front. Aided by the subtropical moisture plume over the Southwest, morning convection near the Four Corners region may move across the higher terrain toward the High Plains, with additional terrain-driven development possible during the afternoon. High-based storms will progress into a well-mixed boundary layer that may initially be devoid of appreciable CAPE. This lack of greater buoyancy during the late afternoon to early evening (outside of areas north of the warm front) yields substantial uncertainty regarding the degree of storm organization into the lower elevations. But with scattered to widespread convection and increasingly extensive outflow expected with time, sporadic severe gusts may occur during the afternoon and evening. Somewhat more favorable low-level moisture and buoyancy may reside near/north of the warm front, from eastern MT into the western Dakotas. While stronger ascent and deep-layer flow may not impinge upon areas north of the front later in the forecast period, there will be some potential for organized convection to develop during the evening as the shortwave trough ejects northeastward. A couple of supercells and/or stronger clusters will be possible within this regime, with a threat of hail and isolated severe gusts. ...Four Corners region... Despite the unfavorable time of day, a few strong storms cannot be ruled out Tuesday morning across the Four Corners region into western CO/NM, in close proximity to the ejecting shortwave trough. Wind profiles will be quite favorable for organized convection, though it remains uncertain if sufficient buoyancy will be present to support any severe threat during the early part of the day. ...Eastern NC/VA... With uncertainty already relatively high regarding evolution of the currently developing offshore low into D2/Monday, confidence remains too low to delineate severe probabilities for D3/Tuesday. Slower and more aggressive ensemble members continue to suggest an adequate SRH/buoyancy combination for low-topped supercells may linger over eastern NC early in the period and shift into parts of eastern VA. However, the bulk of guidance still indicates a general weakening of the low-level wind field during the day. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

10 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Sep 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE HIGH PLAINS... ...SUMMARY... Strong to locally severe thunderstorms will be possible Tuesday across a large swath of the High Plains region, mainly from late afternoon into the evening. Severe gusts should be the primary hazard, though some hail may also be possible. ...High Plains... A mid/upper-level shortwave trough initially over the eastern Great Basin should take on a negative tilt as it advances towards the northern High Plains. Deep lee cyclogenesis is expected over northeast WY/southeast MT, with a warm front extending east-northeast of the low somewhere from eastern MT into the Dakotas during the afternoon and evening. This low will advance north towards the MT/SK border area by 12Z Wednesday. Large-scale ascent will be pronounced within this synoptic regime, with favorable upper-level difluence, mid-level height falls, and low-level convergence. However, weak buoyancy and modest mid-level lapse rates will characterize much of the environment to the south of the surface low and warm front. Aided by the subtropical moisture plume over the Southwest, morning convection near the Four Corners region may move across the higher terrain toward the High Plains, with additional terrain-driven development possible during the afternoon. High-based storms will progress into a well-mixed boundary layer that may initially be devoid of appreciable CAPE. This lack of greater buoyancy during the late afternoon to early evening (outside of areas north of the warm front) yields substantial uncertainty regarding the degree of storm organization into the lower elevations. But with scattered to widespread convection and increasingly extensive outflow expected with time, sporadic severe gusts may occur during the afternoon and evening. Somewhat more favorable low-level moisture and buoyancy may reside near/north of the warm front, from eastern MT into the western Dakotas. While stronger ascent and deep-layer flow may not impinge upon areas north of the front later in the forecast period, there will be some potential for organized convection to develop during the evening as the shortwave trough ejects northeastward. A couple of supercells and/or stronger clusters will be possible within this regime, with a threat of hail and isolated severe gusts. ...Four Corners region... Despite the unfavorable time of day, a few strong storms cannot be ruled out Tuesday morning across the Four Corners region into western CO/NM, in close proximity to the ejecting shortwave trough. Wind profiles will be quite favorable for organized convection, though it remains uncertain if sufficient buoyancy will be present to support any severe threat during the early part of the day. ...Eastern NC/VA... With uncertainty already relatively high regarding evolution of the currently developing offshore low into D2/Monday, confidence remains too low to delineate severe probabilities for D3/Tuesday. Slower and more aggressive ensemble members continue to suggest an adequate SRH/buoyancy combination for low-topped supercells may linger over eastern NC early in the period and shift into parts of eastern VA. However, the bulk of guidance still indicates a general weakening of the low-level wind field during the day. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

10 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Sep 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE HIGH PLAINS... ...SUMMARY... Strong to locally severe thunderstorms will be possible Tuesday across a large swath of the High Plains region, mainly from late afternoon into the evening. Severe gusts should be the primary hazard, though some hail may also be possible. ...High Plains... A mid/upper-level shortwave trough initially over the eastern Great Basin should take on a negative tilt as it advances towards the northern High Plains. Deep lee cyclogenesis is expected over northeast WY/southeast MT, with a warm front extending east-northeast of the low somewhere from eastern MT into the Dakotas during the afternoon and evening. This low will advance north towards the MT/SK border area by 12Z Wednesday. Large-scale ascent will be pronounced within this synoptic regime, with favorable upper-level difluence, mid-level height falls, and low-level convergence. However, weak buoyancy and modest mid-level lapse rates will characterize much of the environment to the south of the surface low and warm front. Aided by the subtropical moisture plume over the Southwest, morning convection near the Four Corners region may move across the higher terrain toward the High Plains, with additional terrain-driven development possible during the afternoon. High-based storms will progress into a well-mixed boundary layer that may initially be devoid of appreciable CAPE. This lack of greater buoyancy during the late afternoon to early evening (outside of areas north of the warm front) yields substantial uncertainty regarding the degree of storm organization into the lower elevations. But with scattered to widespread convection and increasingly extensive outflow expected with time, sporadic severe gusts may occur during the afternoon and evening. Somewhat more favorable low-level moisture and buoyancy may reside near/north of the warm front, from eastern MT into the western Dakotas. While stronger ascent and deep-layer flow may not impinge upon areas north of the front later in the forecast period, there will be some potential for organized convection to develop during the evening as the shortwave trough ejects northeastward. A couple of supercells and/or stronger clusters will be possible within this regime, with a threat of hail and isolated severe gusts. ...Four Corners region... Despite the unfavorable time of day, a few strong storms cannot be ruled out Tuesday morning across the Four Corners region into western CO/NM, in close proximity to the ejecting shortwave trough. Wind profiles will be quite favorable for organized convection, though it remains uncertain if sufficient buoyancy will be present to support any severe threat during the early part of the day. ...Eastern NC/VA... With uncertainty already relatively high regarding evolution of the currently developing offshore low into D2/Monday, confidence remains too low to delineate severe probabilities for D3/Tuesday. Slower and more aggressive ensemble members continue to suggest an adequate SRH/buoyancy combination for low-topped supercells may linger over eastern NC early in the period and shift into parts of eastern VA. However, the bulk of guidance still indicates a general weakening of the low-level wind field during the day. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

10 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sun Sep 15 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE HIGH PLAINS... ...SUMMARY... Strong to locally severe thunderstorms will be possible Tuesday across a large swath of the High Plains region, mainly from late afternoon into the evening. Severe gusts should be the primary hazard, though some hail may also be possible. ...High Plains... A mid/upper-level shortwave trough initially over the eastern Great Basin should take on a negative tilt as it advances towards the northern High Plains. Deep lee cyclogenesis is expected over northeast WY/southeast MT, with a warm front extending east-northeast of the low somewhere from eastern MT into the Dakotas during the afternoon and evening. This low will advance north towards the MT/SK border area by 12Z Wednesday. Large-scale ascent will be pronounced within this synoptic regime, with favorable upper-level difluence, mid-level height falls, and low-level convergence. However, weak buoyancy and modest mid-level lapse rates will characterize much of the environment to the south of the surface low and warm front. Aided by the subtropical moisture plume over the Southwest, morning convection near the Four Corners region may move across the higher terrain toward the High Plains, with additional terrain-driven development possible during the afternoon. High-based storms will progress into a well-mixed boundary layer that may initially be devoid of appreciable CAPE. This lack of greater buoyancy during the late afternoon to early evening (outside of areas north of the warm front) yields substantial uncertainty regarding the degree of storm organization into the lower elevations. But with scattered to widespread convection and increasingly extensive outflow expected with time, sporadic severe gusts may occur during the afternoon and evening. Somewhat more favorable low-level moisture and buoyancy may reside near/north of the warm front, from eastern MT into the western Dakotas. While stronger ascent and deep-layer flow may not impinge upon areas north of the front later in the forecast period, there will be some potential for organized convection to develop during the evening as the shortwave trough ejects northeastward. A couple of supercells and/or stronger clusters will be possible within this regime, with a threat of hail and isolated severe gusts. ...Four Corners region... Despite the unfavorable time of day, a few strong storms cannot be ruled out Tuesday morning across the Four Corners region into western CO/NM, in close proximity to the ejecting shortwave trough. Wind profiles will be quite favorable for organized convection, though it remains uncertain if sufficient buoyancy will be present to support any severe threat during the early part of the day. ...Eastern NC/VA... With uncertainty already relatively high regarding evolution of the currently developing offshore low into D2/Monday, confidence remains too low to delineate severe probabilities for D3/Tuesday. Slower and more aggressive ensemble members continue to suggest an adequate SRH/buoyancy combination for low-topped supercells may linger over eastern NC early in the period and shift into parts of eastern VA. However, the bulk of guidance still indicates a general weakening of the low-level wind field during the day. ..Dean.. 09/15/2024 Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

10 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0204 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z The primary changes to the Day 2 Fire Weather Outlook were to add Elevated highlights to portions of the central High Plains. Surface lee troughing ahead of an approaching broad mid-level trough will encourage 15-20 mph sustained southerly surface winds over the central High Plains (particularly along the KS/CO border), in tandem with 20-25 percent RH. These surface meteorological conditions will overspread modestly dry fuels, warranting Elevated highlights in this region. Surface high pressure over the Northeast will encourage dry easterly surface flow across portions of Ohio and immediate surrounding areas tomorrow, where fuels are anomalously dry and highly supportive of wildfire spread. RH may drop into the 20-25 percent range over these fuels by afternoon peak heating. However, surface sustained wind speeds should be generally under 15 mph, precluding the addition of Elevated highlights this outlook. Nonetheless, given such dry fuels (with a severe to locally extreme drought in place), gusty conditions may support localized brush-fire growth in this regime. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... A highly amplified midlevel trough, accompanied by strong deep-layer south-southwesterly flow, will overspread the Great Basin during the day. This will promote 20-30 mph sustained south-southwesterly surface winds (with higher gusts) across portions of the southern Great Basin. Despite cooling surface temperatures and increasing moisture/RH, diurnal heating should still contribute to a corridor of 15-20 percent RH amid the strong/gusty winds. Therefore, Elevated highlights are in place for the wind-driven fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

Eastern North Pacific Tropical Weather Outlook

10 months ago

000
ABPZ20 KNHC 151735
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sun Sep 15 2024

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

Active Systems:
The National Hurricane Center has issued the last advisory on
Post-Tropical Cyclone Ileana, located over the Gulf of California.

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

$$
Forecaster Kelly
NHC Webmaster

SPC Sep 15, 2024 1730 UTC Day 2 Convective Outlook

10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN GREAT BASIN INTO THE FOUR CORNERS REGION...ND INTO NORTHWEST MN...EASTERN NC AND VICINITY... ...SUMMARY... On Monday, sporadic severe gusts and hail will be possible during the afternoon to early evening across parts of the eastern Great Basin to Four Corners. Isolated severe storms are possible over eastern North Dakota into northwest Minnesota. Some tornado threat may develop over eastern North Carolina and vicinity. ...Eastern Great Basin to the Four Corners... A seasonably strong mid-level low initially near San Francisco Bay Monday morning should move east during the day, before curling northeast Monday night towards the NV/UT/ID border area. This will occur in response to a strong mid-level jet translating through the basal portion of the large-scale trough across the Desert Southwest into the eastern Great Basin. Convection will likely be ongoing at the start of the forecast period near the midlevel low, and also farther east toward the Four Corners region, within the warm/moist conveyor. Relatively strong heating will be possible between these two regimes, from eastern NV into parts of UT. While buoyancy will likely remain quite weak within this warmer and more well-mixed regime, high-based convection will be possible during the afternoon and evening as the midlevel low approaches the region, with increasing meridional flow and a deeply mixed boundary layer supporting isolated severe gusts. Farther southeast into eastern UT and the Four Corners vicinity, increasing southwesterly flow aloft and strengthening deep-layer shear will become conditionally supportive of organized convection. Warmer midlevel temperatures may limit buoyancy to some extent, though sufficient moisture will support afternoon MLCAPE of 500-1000 J/kg. A few supercells will be possible within this regime, with an attendant threat of isolated severe gusts and hail. ...Parts of ND into northern MN... With the primary upper-level trough displaced well to the west, deep-layer shear will remain weak across much of the Great Plains. However, most guidance suggests an MCV will emanate out of central High Plains convection on D1/Sunday and gradually progress northeast towards the Red River Valley during the day on Monday. In conjunction with a strengthening low-level jet, this MCV may help to support relatively vigorous storm redevelopment within a moderately unstable environment during the afternoon and evening. Stronger midlevel flow attendant to the MCV could support some storm organization, and a couple supercells and/or stronger clusters will be possible, with a threat of isolated hail and damaging wind. Somewhat favorable low-level shear/SRH could also support a tornado threat, if a surface-based supercell can be sustained. Uncertainty remains regarding the strength/timing of any MCV moving across the region, along with the most favored corridor for diurnal storm development. ...Eastern NC and vicinity... Guidance generally suggests that an initially offshore surface low will move northward or northwestward from later on D1/Sunday into D2/Monday and D3/Tuesday, and eventually move inland across some part of the Carolinas. However, uncertainty remains regarding the timing, track, and intensity of this low, along with the extent to which it acquires any tropical or subtropical characteristics. If a deepening low does move onshore, then a higher theta-e airmass may move inland, accompanied by increasing low-level shear/SRH along/north of the low track. While the general scenario supports some potential for low-topped supercells, the magnitude of any tornado threat will be dependent on the extent of intensification that occurs with the low (and its attendant wind fields) prior to landfall. The Marginal Risk has been expanded somewhat across eastern NC and vicinity, in response to the various uncertainties. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1730 UTC Day 2 Convective Outlook

10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN GREAT BASIN INTO THE FOUR CORNERS REGION...ND INTO NORTHWEST MN...EASTERN NC AND VICINITY... ...SUMMARY... On Monday, sporadic severe gusts and hail will be possible during the afternoon to early evening across parts of the eastern Great Basin to Four Corners. Isolated severe storms are possible over eastern North Dakota into northwest Minnesota. Some tornado threat may develop over eastern North Carolina and vicinity. ...Eastern Great Basin to the Four Corners... A seasonably strong mid-level low initially near San Francisco Bay Monday morning should move east during the day, before curling northeast Monday night towards the NV/UT/ID border area. This will occur in response to a strong mid-level jet translating through the basal portion of the large-scale trough across the Desert Southwest into the eastern Great Basin. Convection will likely be ongoing at the start of the forecast period near the midlevel low, and also farther east toward the Four Corners region, within the warm/moist conveyor. Relatively strong heating will be possible between these two regimes, from eastern NV into parts of UT. While buoyancy will likely remain quite weak within this warmer and more well-mixed regime, high-based convection will be possible during the afternoon and evening as the midlevel low approaches the region, with increasing meridional flow and a deeply mixed boundary layer supporting isolated severe gusts. Farther southeast into eastern UT and the Four Corners vicinity, increasing southwesterly flow aloft and strengthening deep-layer shear will become conditionally supportive of organized convection. Warmer midlevel temperatures may limit buoyancy to some extent, though sufficient moisture will support afternoon MLCAPE of 500-1000 J/kg. A few supercells will be possible within this regime, with an attendant threat of isolated severe gusts and hail. ...Parts of ND into northern MN... With the primary upper-level trough displaced well to the west, deep-layer shear will remain weak across much of the Great Plains. However, most guidance suggests an MCV will emanate out of central High Plains convection on D1/Sunday and gradually progress northeast towards the Red River Valley during the day on Monday. In conjunction with a strengthening low-level jet, this MCV may help to support relatively vigorous storm redevelopment within a moderately unstable environment during the afternoon and evening. Stronger midlevel flow attendant to the MCV could support some storm organization, and a couple supercells and/or stronger clusters will be possible, with a threat of isolated hail and damaging wind. Somewhat favorable low-level shear/SRH could also support a tornado threat, if a surface-based supercell can be sustained. Uncertainty remains regarding the strength/timing of any MCV moving across the region, along with the most favored corridor for diurnal storm development. ...Eastern NC and vicinity... Guidance generally suggests that an initially offshore surface low will move northward or northwestward from later on D1/Sunday into D2/Monday and D3/Tuesday, and eventually move inland across some part of the Carolinas. However, uncertainty remains regarding the timing, track, and intensity of this low, along with the extent to which it acquires any tropical or subtropical characteristics. If a deepening low does move onshore, then a higher theta-e airmass may move inland, accompanied by increasing low-level shear/SRH along/north of the low track. While the general scenario supports some potential for low-topped supercells, the magnitude of any tornado threat will be dependent on the extent of intensification that occurs with the low (and its attendant wind fields) prior to landfall. The Marginal Risk has been expanded somewhat across eastern NC and vicinity, in response to the various uncertainties. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1730 UTC Day 2 Convective Outlook

10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN GREAT BASIN INTO THE FOUR CORNERS REGION...ND INTO NORTHWEST MN...EASTERN NC AND VICINITY... ...SUMMARY... On Monday, sporadic severe gusts and hail will be possible during the afternoon to early evening across parts of the eastern Great Basin to Four Corners. Isolated severe storms are possible over eastern North Dakota into northwest Minnesota. Some tornado threat may develop over eastern North Carolina and vicinity. ...Eastern Great Basin to the Four Corners... A seasonably strong mid-level low initially near San Francisco Bay Monday morning should move east during the day, before curling northeast Monday night towards the NV/UT/ID border area. This will occur in response to a strong mid-level jet translating through the basal portion of the large-scale trough across the Desert Southwest into the eastern Great Basin. Convection will likely be ongoing at the start of the forecast period near the midlevel low, and also farther east toward the Four Corners region, within the warm/moist conveyor. Relatively strong heating will be possible between these two regimes, from eastern NV into parts of UT. While buoyancy will likely remain quite weak within this warmer and more well-mixed regime, high-based convection will be possible during the afternoon and evening as the midlevel low approaches the region, with increasing meridional flow and a deeply mixed boundary layer supporting isolated severe gusts. Farther southeast into eastern UT and the Four Corners vicinity, increasing southwesterly flow aloft and strengthening deep-layer shear will become conditionally supportive of organized convection. Warmer midlevel temperatures may limit buoyancy to some extent, though sufficient moisture will support afternoon MLCAPE of 500-1000 J/kg. A few supercells will be possible within this regime, with an attendant threat of isolated severe gusts and hail. ...Parts of ND into northern MN... With the primary upper-level trough displaced well to the west, deep-layer shear will remain weak across much of the Great Plains. However, most guidance suggests an MCV will emanate out of central High Plains convection on D1/Sunday and gradually progress northeast towards the Red River Valley during the day on Monday. In conjunction with a strengthening low-level jet, this MCV may help to support relatively vigorous storm redevelopment within a moderately unstable environment during the afternoon and evening. Stronger midlevel flow attendant to the MCV could support some storm organization, and a couple supercells and/or stronger clusters will be possible, with a threat of isolated hail and damaging wind. Somewhat favorable low-level shear/SRH could also support a tornado threat, if a surface-based supercell can be sustained. Uncertainty remains regarding the strength/timing of any MCV moving across the region, along with the most favored corridor for diurnal storm development. ...Eastern NC and vicinity... Guidance generally suggests that an initially offshore surface low will move northward or northwestward from later on D1/Sunday into D2/Monday and D3/Tuesday, and eventually move inland across some part of the Carolinas. However, uncertainty remains regarding the timing, track, and intensity of this low, along with the extent to which it acquires any tropical or subtropical characteristics. If a deepening low does move onshore, then a higher theta-e airmass may move inland, accompanied by increasing low-level shear/SRH along/north of the low track. While the general scenario supports some potential for low-topped supercells, the magnitude of any tornado threat will be dependent on the extent of intensification that occurs with the low (and its attendant wind fields) prior to landfall. The Marginal Risk has been expanded somewhat across eastern NC and vicinity, in response to the various uncertainties. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1730 UTC Day 2 Convective Outlook

10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN GREAT BASIN INTO THE FOUR CORNERS REGION...ND INTO NORTHWEST MN...EASTERN NC AND VICINITY... ...SUMMARY... On Monday, sporadic severe gusts and hail will be possible during the afternoon to early evening across parts of the eastern Great Basin to Four Corners. Isolated severe storms are possible over eastern North Dakota into northwest Minnesota. Some tornado threat may develop over eastern North Carolina and vicinity. ...Eastern Great Basin to the Four Corners... A seasonably strong mid-level low initially near San Francisco Bay Monday morning should move east during the day, before curling northeast Monday night towards the NV/UT/ID border area. This will occur in response to a strong mid-level jet translating through the basal portion of the large-scale trough across the Desert Southwest into the eastern Great Basin. Convection will likely be ongoing at the start of the forecast period near the midlevel low, and also farther east toward the Four Corners region, within the warm/moist conveyor. Relatively strong heating will be possible between these two regimes, from eastern NV into parts of UT. While buoyancy will likely remain quite weak within this warmer and more well-mixed regime, high-based convection will be possible during the afternoon and evening as the midlevel low approaches the region, with increasing meridional flow and a deeply mixed boundary layer supporting isolated severe gusts. Farther southeast into eastern UT and the Four Corners vicinity, increasing southwesterly flow aloft and strengthening deep-layer shear will become conditionally supportive of organized convection. Warmer midlevel temperatures may limit buoyancy to some extent, though sufficient moisture will support afternoon MLCAPE of 500-1000 J/kg. A few supercells will be possible within this regime, with an attendant threat of isolated severe gusts and hail. ...Parts of ND into northern MN... With the primary upper-level trough displaced well to the west, deep-layer shear will remain weak across much of the Great Plains. However, most guidance suggests an MCV will emanate out of central High Plains convection on D1/Sunday and gradually progress northeast towards the Red River Valley during the day on Monday. In conjunction with a strengthening low-level jet, this MCV may help to support relatively vigorous storm redevelopment within a moderately unstable environment during the afternoon and evening. Stronger midlevel flow attendant to the MCV could support some storm organization, and a couple supercells and/or stronger clusters will be possible, with a threat of isolated hail and damaging wind. Somewhat favorable low-level shear/SRH could also support a tornado threat, if a surface-based supercell can be sustained. Uncertainty remains regarding the strength/timing of any MCV moving across the region, along with the most favored corridor for diurnal storm development. ...Eastern NC and vicinity... Guidance generally suggests that an initially offshore surface low will move northward or northwestward from later on D1/Sunday into D2/Monday and D3/Tuesday, and eventually move inland across some part of the Carolinas. However, uncertainty remains regarding the timing, track, and intensity of this low, along with the extent to which it acquires any tropical or subtropical characteristics. If a deepening low does move onshore, then a higher theta-e airmass may move inland, accompanied by increasing low-level shear/SRH along/north of the low track. While the general scenario supports some potential for low-topped supercells, the magnitude of any tornado threat will be dependent on the extent of intensification that occurs with the low (and its attendant wind fields) prior to landfall. The Marginal Risk has been expanded somewhat across eastern NC and vicinity, in response to the various uncertainties. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1730 UTC Day 2 Convective Outlook

10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN GREAT BASIN INTO THE FOUR CORNERS REGION...ND INTO NORTHWEST MN...EASTERN NC AND VICINITY... ...SUMMARY... On Monday, sporadic severe gusts and hail will be possible during the afternoon to early evening across parts of the eastern Great Basin to Four Corners. Isolated severe storms are possible over eastern North Dakota into northwest Minnesota. Some tornado threat may develop over eastern North Carolina and vicinity. ...Eastern Great Basin to the Four Corners... A seasonably strong mid-level low initially near San Francisco Bay Monday morning should move east during the day, before curling northeast Monday night towards the NV/UT/ID border area. This will occur in response to a strong mid-level jet translating through the basal portion of the large-scale trough across the Desert Southwest into the eastern Great Basin. Convection will likely be ongoing at the start of the forecast period near the midlevel low, and also farther east toward the Four Corners region, within the warm/moist conveyor. Relatively strong heating will be possible between these two regimes, from eastern NV into parts of UT. While buoyancy will likely remain quite weak within this warmer and more well-mixed regime, high-based convection will be possible during the afternoon and evening as the midlevel low approaches the region, with increasing meridional flow and a deeply mixed boundary layer supporting isolated severe gusts. Farther southeast into eastern UT and the Four Corners vicinity, increasing southwesterly flow aloft and strengthening deep-layer shear will become conditionally supportive of organized convection. Warmer midlevel temperatures may limit buoyancy to some extent, though sufficient moisture will support afternoon MLCAPE of 500-1000 J/kg. A few supercells will be possible within this regime, with an attendant threat of isolated severe gusts and hail. ...Parts of ND into northern MN... With the primary upper-level trough displaced well to the west, deep-layer shear will remain weak across much of the Great Plains. However, most guidance suggests an MCV will emanate out of central High Plains convection on D1/Sunday and gradually progress northeast towards the Red River Valley during the day on Monday. In conjunction with a strengthening low-level jet, this MCV may help to support relatively vigorous storm redevelopment within a moderately unstable environment during the afternoon and evening. Stronger midlevel flow attendant to the MCV could support some storm organization, and a couple supercells and/or stronger clusters will be possible, with a threat of isolated hail and damaging wind. Somewhat favorable low-level shear/SRH could also support a tornado threat, if a surface-based supercell can be sustained. Uncertainty remains regarding the strength/timing of any MCV moving across the region, along with the most favored corridor for diurnal storm development. ...Eastern NC and vicinity... Guidance generally suggests that an initially offshore surface low will move northward or northwestward from later on D1/Sunday into D2/Monday and D3/Tuesday, and eventually move inland across some part of the Carolinas. However, uncertainty remains regarding the timing, track, and intensity of this low, along with the extent to which it acquires any tropical or subtropical characteristics. If a deepening low does move onshore, then a higher theta-e airmass may move inland, accompanied by increasing low-level shear/SRH along/north of the low track. While the general scenario supports some potential for low-topped supercells, the magnitude of any tornado threat will be dependent on the extent of intensification that occurs with the low (and its attendant wind fields) prior to landfall. The Marginal Risk has been expanded somewhat across eastern NC and vicinity, in response to the various uncertainties. ..Dean.. 09/15/2024 Read more

SPC Sep 15, 2024 1730 UTC Day 2 Convective Outlook

10 months ago
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Sun Sep 15 2024 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN GREAT BASIN INTO THE FOUR CORNERS REGION...ND INTO NORTHWEST MN...EASTERN NC AND VICINITY... ...SUMMARY... On Monday, sporadic severe gusts and hail will be possible during the afternoon to early evening across parts of the eastern Great Basin to Four Corners. Isolated severe storms are possible over eastern North Dakota into northwest Minnesota. Some tornado threat may develop over eastern North Carolina and vicinity. ...Eastern Great Basin to the Four Corners... A seasonably strong mid-level low initially near San Francisco Bay Monday morning should move east during the day, before curling northeast Monday night towards the NV/UT/ID border area. This will occur in response to a strong mid-level jet translating through the basal portion of the large-scale trough across the Desert Southwest into the eastern Great Basin. Convection will likely be ongoing at the start of the forecast period near the midlevel low, and also farther east toward the Four Corners region, within the warm/moist conveyor. Relatively strong heating will be possible between these two regimes, from eastern NV into parts of UT. While buoyancy will likely remain quite weak within this warmer and more well-mixed regime, high-based convection will be possible during the afternoon and evening as the midlevel low approaches the region, with increasing meridional flow and a deeply mixed boundary layer supporting isolated severe gusts. Farther southeast into eastern UT and the Four Corners vicinity, increasing southwesterly flow aloft and strengthening deep-layer shear will become conditionally supportive of organized convection. Warmer midlevel temperatures may limit buoyancy to some extent, though sufficient moisture will support afternoon MLCAPE of 500-1000 J/kg. A few supercells will be possible within this regime, with an attendant threat of isolated severe gusts and hail. ...Parts of ND into northern MN... With the primary upper-level trough displaced well to the west, deep-layer shear will remain weak across much of the Great Plains. However, most guidance suggests an MCV will emanate out of central High Plains convection on D1/Sunday and gradually progress northeast towards the Red River Valley during the day on Monday. In conjunction with a strengthening low-level jet, this MCV may help to support relatively vigorous storm redevelopment within a moderately unstable environment during the afternoon and evening. Stronger midlevel flow attendant to the MCV could support some storm organization, and a couple supercells and/or stronger clusters will be possible, with a threat of isolated hail and damaging wind. Somewhat favorable low-level shear/SRH could also support a tornado threat, if a surface-based supercell can be sustained. Uncertainty remains regarding the strength/timing of any MCV moving across the region, along with the most favored corridor for diurnal storm development. ...Eastern NC and vicinity... Guidance generally suggests that an initially offshore surface low will move northward or northwestward from later on D1/Sunday into D2/Monday and D3/Tuesday, and eventually move inland across some part of the Carolinas. However, uncertainty remains regarding the timing, track, and intensity of this low, along with the extent to which it acquires any tropical or subtropical characteristics. If a deepening low does move onshore, then a higher theta-e airmass may move inland, accompanied by increasing low-level shear/SRH along/north of the low track. While the general scenario supports some potential for low-topped supercells, the magnitude of any tornado threat will be dependent on the extent of intensification that occurs with the low (and its attendant wind fields) prior to landfall. The Marginal Risk has been expanded somewhat across eastern NC and vicinity, in response to the various uncertainties. ..Dean.. 09/15/2024 Read more