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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Sun Sep 15 2024 Valid 151630Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Thunderstorms capable of producing isolated severe gusts and hail may occur today and tonight across parts of the northern/central Plains. ...Northern/Central Plains... An amplified upper trough along/near the West Coast this morning will further evolve into a closed upper low over northern CA and vicinity by late tonight. Ahead of this feature, modestly enhanced south-southwesterly mid-level flow will be in place over much of the western states and Rockies through the period. Although low-level moisture is expected to remain limited over much of this region, isolated strong to severe gusts may occur with any thunderstorms that can develop in a deeply mixed boundary layer favorable for gusty downdraft winds. Latest guidance continues to suggest that a relatively greater concentration of severe potential will be focused across parts of the northern/central Plains late this afternoon through tonight. Across this area, a weak surface lee trough and greater low-level moisture to its east should support weak to moderate instability with daytime heating. Steep mid-level lapse rates should also aid updraft accelerations/intensities, with around 20-30 kt of deep-layer shear supporting modest thunderstorm organization. Isolated severe hail may occur with initially more discrete convection, but a tendency for clustering should lead to a relatively greater wind threat with time as convection spreads generally east-northeastward through the evening. Regardless, the overall severe threat from northeast CO into western NE/SD and vicinity should remain fairly isolated/marginal given the modest deep-layer shear. Low-level warm advection is forecast to increase across much of the northern/central Plains tonight as a southerly low-level jet strengthens. A surface warm front is also expected to lift northward over ND late tonight into early Monday morning. With steepening mid-level lapse rates overspreading the northern Plains in tandem with increasing low-level moisture, ample MUCAPE should be available. Most guidance shows at least isolated convection developing across parts of ND tonight in this favorable thermodynamic environment. Although deep-layer shear may remain fairly modest, it may still be sufficient for updraft organization and an isolated threat for severe hail with any elevated convection that can form. Have therefore expanded the Marginal Risk northward to account for this potential. ...Coastal Carolinas... Latest NHC forecast continues to indicate some potential for sub-tropical or tropical development of a surface low currently off the SC Coast. Regardless of development, it still appears that the more moist/tropical low-level airmass over the Gulf Stream will struggle to advance inland over coastal portions of NC/SC through the end of the Day 1 forecast period early Monday morning (16/12Z). Accordingly, tornado potential with any low-topped supercells on the north to northeast periphery of the surface low should tend to remain offshore until Day 2/Monday (after 16/12Z). ..Gleason/Moore.. 09/15/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CDT Sun Sep 15 2024 Valid 151700Z - 161200Z The previous forecast remains on track, with minor changes made to the Elevated areas to reflect the latest guidance consensus. Additionally, a couple of dry strikes may accompany isolated thunderstorms along the Front Range in eastern Colorado (and surrounding areas), but overall modest fuel receptiveness suggests that lightning-induced fire ignitions should remain a localized concern, so no isolated dry thunderstorm highlights have been added. ..Squitieri.. 09/15/2024 .PREV DISCUSSION... /ISSUED 0150 AM CDT Sun Sep 15 2024/ ...Synopsis... Preceding an amplifying large-scale trough over the West Coast, enhanced deep-layer meridional flow will overspread the Great Basin, while a related surface cyclone evolves over northern NV. Deep boundary-layer mixing into the enhanced flow aloft, along with a tightening pressure gradient peripheral to the surface cyclone, will yield 20-25 mph sustained southerly surface winds and 15-20 percent RH over southern/central NV. Given modestly receptive fuels here, elevated fire-weather conditions are expected during the afternoon. Additionally, large-scale ascent accompanying the amplifying midlevel trough will promote a mix of wet/dry thunderstorms across the northern Great Basin/Intermountain West. While quick storm motions and limited precipitation with some of this activity could yield a risk of lightning-induced ignitions, marginal fuels should generally limit the threat. Over the southern High Plains, breezy/gusty southerly surface winds will develop amid a warm/dry boundary layer near a lee trough during the afternoon. This will favor a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

5-Day Uncertainty Track last updated Sun, 15 Sep 2024 14:41:29 GMT


Wind Speed Probabilities last updated Sun, 15 Sep 2024 15:28:48 GMT

Issued at 800 AM MST Sun Sep 15 2024 227 WTPZ44 KNHC 151440 TCDEP4 Post-Tropical Cyclone Ileana Discussion Number 13 NWS National Hurricane Center Miami FL EP092024 800 AM MST Sun Sep 15 2024 Ileana has been devoid of deep convection since yesterday afternoon, as the system has been within a strong wind shear and very dry environment. Given the lack of convection, the system is being designated as a post-tropical remnant low. An ASCAT-C pass from late last night depicted winds near 30 kt over the Gulf of California near northern Sinaloa. Given this, will hold the intensity at 30 kt for this advisory, although that may be generous. The system has been meandering over the Gulf of California with a motion of 310/3 kt. The remnant low will increase forward speed later today as it continues northwestward. The remnant low will continue to weaken throughout the day, and is forecast to dissipate on Monday. This is the last advisory on this system. For additional information on the remnant low please see High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFEPI, WMO header FZPN02 KWBC, and on the web at ocean.weather.gov/shtml/NFDHSFEPI.php FORECAST POSITIONS AND MAX WINDS INIT 15/1500Z 25.7N 109.6W 30 KT 35 MPH...POST-TROPICAL 12H 16/0000Z 26.1N 110.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 24H 16/1200Z 27.3N 111.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 36H 17/0000Z...DISSIPATED $$ Forecaster Kelly

Issued at 800 AM MST Sun Sep 15 2024 247 WTPZ34 KNHC 151439 TCPEP4 BULLETIN Post-Tropical Cyclone Ileana Advisory Number 13 NWS National Hurricane Center Miami FL EP092024 800 AM MST Sun Sep 15 2024 ...ILEANA BECOMES A REMNANT LOW... ...THIS IS THE LAST ADVISORY... SUMMARY OF 800 AM MST...1500 UTC...INFORMATION ---------------------------------------------- LOCATION...25.7N 109.6W ABOUT 40 MI...60 KM W OF LOS MOCHIS MEXICO MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...NW OR 310 DEGREES AT 3 MPH...6 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 800 AM MST (1500 UTC), the center of Post-Tropical Cyclone Ileana was located near latitude 25.7 North, longitude 109.6 West. The post-tropical cyclone is moving toward the northwest near 3 mph (6 km/h). A slow northwestward motion will continue through Monday. On the forecast track, the remnant low will move over the Gulf of California near the coasts of northern Sinaloa and southern Sonora. Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. The remnant low is forecast to weaken today and dissipate on Monday. The estimated minimum central pressure is 1006 mb (29.71 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Ileana may bring an additional 1 to 2 inches of rainfall to portions of northwest Sinaloa through today. For a complete depiction of forecast rainfall associated with Ileana, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep4.shtml?rainqpf WIND: Gusty winds are still possible along the coasts of northern Sinaloa and southern Sonora through this morning. SURF: Swells generated by Ileana will continue to subside along the Gulf of California coasts of Sinaloa, southern Sonora, and southern Baja California Sur today. NEXT ADVISORY ------------- This is the last public advisory issued by the National Hurricane Center on this system. For additional information on the remnant low please see High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFEPI, WMO header FZPN02 KWBC, and on the web at ocean.weather.gov/shtml/NFDHSFEPI.php $$ Forecaster Kelly

...ILEANA BECOMES A REMNANT LOW... ...THIS IS THE LAST ADVISORY... As of 8:00 AM MST Sun Sep 15 the center of Ileana was located near 25.7, -109.6 with movement NW at 3 mph. The minimum central pressure was 1006 mb with maximum sustained winds of about 35 mph.

Issued at 1500 UTC SUN SEP 15 2024 221 FOPZ14 KNHC 151439 PWSEP4 POST-TROPICAL CYCLONE ILEANA WIND SPEED PROBABILITIES NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092024 1500 UTC SUN SEP 15 2024 AT 1500Z THE CENTER OF POST-TROPICAL CYCLONE ILEANA WAS LOCATED NEAR LATITUDE 25.7 NORTH...LONGITUDE 109.6 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 30 KTS...35 MPH...55 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 12Z SUN AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 12Z SUN 00Z MON 12Z MON 00Z TUE 12Z TUE 12Z WED 12Z THU PERIODS TO TO TO TO TO TO TO 00Z MON 12Z MON 00Z TUE 12Z TUE 12Z WED 12Z THU 12Z FRI FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT $$ FORECASTER KELLY

Issued at 1500 UTC SUN SEP 15 2024 198 WTPZ24 KNHC 151438 TCMEP4 POST-TROPICAL CYCLONE ILEANA FORECAST/ADVISORY NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092024 1500 UTC SUN SEP 15 2024 POST-TROPICAL CYCLONE CENTER LOCATED NEAR 25.7N 109.6W AT 15/1500Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 310 DEGREES AT 3 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 25.7N 109.6W AT 15/1500Z AT 15/1200Z CENTER WAS LOCATED NEAR 25.5N 109.5W FORECAST VALID 16/0000Z 26.1N 110.1W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 16/1200Z 27.3N 111.0W...POST-TROP/REMNT LOW MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 17/0000Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 25.7N 109.6W THIS IS THE LAST FORECAST/ADVISORY ISSUED BY THE NATIONAL HURRICANE CENTER ON THIS SYSTEM. FOR ADDITIONAL INFORMATION ON THE REMNANT LOW PLEASE SEE HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFEPI AND WMO HEADER FZPN02 KWBC. $$ FORECASTER KELLY