Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1207 PM CDT Wed Sep 04 2024 Valid 041700Z - 051200Z ...NO CRITICAL AREAS... No changes are needed to the D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 09/04/2024 .PREV DISCUSSION... /ISSUED 0108 AM CDT Wed Sep 04 2024/ ...Synopsis... Fire weather concerns appear limited for today across the country. Breezy conditions will persist across the central Plains ahead of a migratory surface trough. Low-level moisture has begun to advect northward based on early-morning surface observations, and this trend should continue through the day and modulate afternoon RH minimums over the Plains. Areas of elevated fire weather conditions are possible across central to southern UT as a cold front pushes across the region, but confidence in prolonged/widespread elevated conditions is limited and should occur over fuels that are only modestly receptive. Dry conditions will persist across the Great Basin and West Coast, but a building ridge over the western CONUS will promote weak surface winds and limited fire concerns. ...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 1207 PM CDT Wed Sep 04 2024 Valid 041700Z - 051200Z ...NO CRITICAL AREAS... No changes are needed to the D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 09/04/2024 .PREV DISCUSSION... /ISSUED 0108 AM CDT Wed Sep 04 2024/ ...Synopsis... Fire weather concerns appear limited for today across the country. Breezy conditions will persist across the central Plains ahead of a migratory surface trough. Low-level moisture has begun to advect northward based on early-morning surface observations, and this trend should continue through the day and modulate afternoon RH minimums over the Plains. Areas of elevated fire weather conditions are possible across central to southern UT as a cold front pushes across the region, but confidence in prolonged/widespread elevated conditions is limited and should occur over fuels that are only modestly receptive. Dry conditions will persist across the Great Basin and West Coast, but a building ridge over the western CONUS will promote weak surface winds and limited fire concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2024 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the central High Plains... Recent satellite imagery reveals a broad shortwave trough currently moving through southern ID and northern NV/UT. This shortwave trough and accompanying cold mid-level temperatures are forecast to continue eastward throughout the day, progressing across WY and northern CO. Modest buoyancy, fostered mainly by cooling mid-level temperatures, is anticipated across WY and adjacent parts of northern CO as the shortwave trough progresses through. Thunderstorm development is expected as the large-scale ascent attendant to the shortwave trough interacts with this buoyancy during the afternoon. Moderate mid-level westerlies will accompany this shortwave trough as well, with the resulting increase in vertical shear supporting the potential for a few more organized/persistent storms. Initially more cellular development across the higher terrain could pose a risk for isolated hail, particularly across south-central WY and north-central CO where the best overlap between the stronger shear and cold mid-level temperatures is expected. Damaging wind gusts are possible as well, particularly as the storms reach the lower elevations of central High Plains where a deeply mixed boundary layer will be in place. ...Central Plains into the Upper MS Valley... Recent surface analysis places a low over southeast ND, with weak troughing extending southwestward from this low in east-central CO. The primary cold front is west of this surface trough, extending from the low over southeast ND into more of northwest SD and adjacent northeast WY. The surface low is forecast to progress east-southeastward throughout the day, reaching south-central MN by late tonight. The attendant cold front is expected to push southward during the same period, progressing through much of NE by early Thursday morning. Warm mid-level temperatures should preclude thunderstorm development along the surface trough during the afternoon and evening. A few isolated storms are possible during the evening behind the front as the shortwave trough ejects out into the central Plains. Additional thunderstorm development is expected overnight/early Thursday morning across the Upper MS Valley, with some isolated hail possible within the strongest storms. ..Mosier/Flournoy.. 09/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0716 AM CDT Wed Sep 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the Northern/Central Plains and Upper Mississippi Valley... A weak shortwave trough over the northern Rockies and adjacent Great Basin this morning will become absorbed later today into an amplifying upper trough over the Canadian Prairie provinces and northern Plains. At the surface, a cold front related to the upper trough will continue southward over the northern Plains, and southeastward across the Upper MS Valley through the period. Modest low-level moisture is forecast to be in place ahead of this boundary across the northern Plains and upper MS Valley, with more limited moisture expected farther west across the central Rockies and adjacent High Plains. Relatively cool mid-level temperatures associated with the weak shortwave trough and the presence of steep mid-level lapse rates should aid in the development of weak instability across parts of WY, northern CO, and vicinity this afternoon. Sufficient deep-layer shear (generally 25-35 kt) should support some updraft organization with convection that initially forms over the higher terrain before subsequently spreading eastward. Isolated instances of marginally severe hail and strong/gusty winds may occur with the more cellular development. But, some increase in strong to severe wind potential may be realized as thunderstorms move into an area of steeper low-level lapse rates across the central High Plains by late this afternoon and early evening, especially if any small clusters can form. The severe potential along much of the length of the front in the northern Plains and upper MS Valley appears rather conditional. While large-scale ascent associated with the approaching upper trough should gradually overspread the warm sector by late afternoon/early evening, most guidance continues to suggest that a cap and substantial MLCIN will hinder robust convection from developing through much of the day. Even so, sufficient instability and shear should be in place along/ahead of the front to support an isolated hail/wind threat if thunderstorms can form and be sustained through the evening and early overnight period. The post-frontal regime across much of MT into ND and western SD appears unlikely to support severe convection. Accordingly, the Marginal Risk has been trimmed southward to account for recent guidance and observational trends. ..Gleason/Leitman.. 09/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0716 AM CDT Wed Sep 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the Northern/Central Plains and Upper Mississippi Valley... A weak shortwave trough over the northern Rockies and adjacent Great Basin this morning will become absorbed later today into an amplifying upper trough over the Canadian Prairie provinces and northern Plains. At the surface, a cold front related to the upper trough will continue southward over the northern Plains, and southeastward across the Upper MS Valley through the period. Modest low-level moisture is forecast to be in place ahead of this boundary across the northern Plains and upper MS Valley, with more limited moisture expected farther west across the central Rockies and adjacent High Plains. Relatively cool mid-level temperatures associated with the weak shortwave trough and the presence of steep mid-level lapse rates should aid in the development of weak instability across parts of WY, northern CO, and vicinity this afternoon. Sufficient deep-layer shear (generally 25-35 kt) should support some updraft organization with convection that initially forms over the higher terrain before subsequently spreading eastward. Isolated instances of marginally severe hail and strong/gusty winds may occur with the more cellular development. But, some increase in strong to severe wind potential may be realized as thunderstorms move into an area of steeper low-level lapse rates across the central High Plains by late this afternoon and early evening, especially if any small clusters can form. The severe potential along much of the length of the front in the northern Plains and upper MS Valley appears rather conditional. While large-scale ascent associated with the approaching upper trough should gradually overspread the warm sector by late afternoon/early evening, most guidance continues to suggest that a cap and substantial MLCIN will hinder robust convection from developing through much of the day. Even so, sufficient instability and shear should be in place along/ahead of the front to support an isolated hail/wind threat if thunderstorms can form and be sustained through the evening and early overnight period. The post-frontal regime across much of MT into ND and western SD appears unlikely to support severe convection. Accordingly, the Marginal Risk has been trimmed southward to account for recent guidance and observational trends. ..Gleason/Leitman.. 09/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0716 AM CDT Wed Sep 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the Northern/Central Plains and Upper Mississippi Valley... A weak shortwave trough over the northern Rockies and adjacent Great Basin this morning will become absorbed later today into an amplifying upper trough over the Canadian Prairie provinces and northern Plains. At the surface, a cold front related to the upper trough will continue southward over the northern Plains, and southeastward across the Upper MS Valley through the period. Modest low-level moisture is forecast to be in place ahead of this boundary across the northern Plains and upper MS Valley, with more limited moisture expected farther west across the central Rockies and adjacent High Plains. Relatively cool mid-level temperatures associated with the weak shortwave trough and the presence of steep mid-level lapse rates should aid in the development of weak instability across parts of WY, northern CO, and vicinity this afternoon. Sufficient deep-layer shear (generally 25-35 kt) should support some updraft organization with convection that initially forms over the higher terrain before subsequently spreading eastward. Isolated instances of marginally severe hail and strong/gusty winds may occur with the more cellular development. But, some increase in strong to severe wind potential may be realized as thunderstorms move into an area of steeper low-level lapse rates across the central High Plains by late this afternoon and early evening, especially if any small clusters can form. The severe potential along much of the length of the front in the northern Plains and upper MS Valley appears rather conditional. While large-scale ascent associated with the approaching upper trough should gradually overspread the warm sector by late afternoon/early evening, most guidance continues to suggest that a cap and substantial MLCIN will hinder robust convection from developing through much of the day. Even so, sufficient instability and shear should be in place along/ahead of the front to support an isolated hail/wind threat if thunderstorms can form and be sustained through the evening and early overnight period. The post-frontal regime across much of MT into ND and western SD appears unlikely to support severe convection. Accordingly, the Marginal Risk has been trimmed southward to account for recent guidance and observational trends. ..Gleason/Leitman.. 09/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0716 AM CDT Wed Sep 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the Northern/Central Plains and Upper Mississippi Valley... A weak shortwave trough over the northern Rockies and adjacent Great Basin this morning will become absorbed later today into an amplifying upper trough over the Canadian Prairie provinces and northern Plains. At the surface, a cold front related to the upper trough will continue southward over the northern Plains, and southeastward across the Upper MS Valley through the period. Modest low-level moisture is forecast to be in place ahead of this boundary across the northern Plains and upper MS Valley, with more limited moisture expected farther west across the central Rockies and adjacent High Plains. Relatively cool mid-level temperatures associated with the weak shortwave trough and the presence of steep mid-level lapse rates should aid in the development of weak instability across parts of WY, northern CO, and vicinity this afternoon. Sufficient deep-layer shear (generally 25-35 kt) should support some updraft organization with convection that initially forms over the higher terrain before subsequently spreading eastward. Isolated instances of marginally severe hail and strong/gusty winds may occur with the more cellular development. But, some increase in strong to severe wind potential may be realized as thunderstorms move into an area of steeper low-level lapse rates across the central High Plains by late this afternoon and early evening, especially if any small clusters can form. The severe potential along much of the length of the front in the northern Plains and upper MS Valley appears rather conditional. While large-scale ascent associated with the approaching upper trough should gradually overspread the warm sector by late afternoon/early evening, most guidance continues to suggest that a cap and substantial MLCIN will hinder robust convection from developing through much of the day. Even so, sufficient instability and shear should be in place along/ahead of the front to support an isolated hail/wind threat if thunderstorms can form and be sustained through the evening and early overnight period. The post-frontal regime across much of MT into ND and western SD appears unlikely to support severe convection. Accordingly, the Marginal Risk has been trimmed southward to account for recent guidance and observational trends. ..Gleason/Leitman.. 09/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0716 AM CDT Wed Sep 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL ROCKIES INTO THE NORTHERN/CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms capable of gusty winds and hail may occur this afternoon and evening across parts of the central Rockies into the northern/central Plains and upper Mississippi Valley. ...Central Rockies into the Northern/Central Plains and Upper Mississippi Valley... A weak shortwave trough over the northern Rockies and adjacent Great Basin this morning will become absorbed later today into an amplifying upper trough over the Canadian Prairie provinces and northern Plains. At the surface, a cold front related to the upper trough will continue southward over the northern Plains, and southeastward across the Upper MS Valley through the period. Modest low-level moisture is forecast to be in place ahead of this boundary across the northern Plains and upper MS Valley, with more limited moisture expected farther west across the central Rockies and adjacent High Plains. Relatively cool mid-level temperatures associated with the weak shortwave trough and the presence of steep mid-level lapse rates should aid in the development of weak instability across parts of WY, northern CO, and vicinity this afternoon. Sufficient deep-layer shear (generally 25-35 kt) should support some updraft organization with convection that initially forms over the higher terrain before subsequently spreading eastward. Isolated instances of marginally severe hail and strong/gusty winds may occur with the more cellular development. But, some increase in strong to severe wind potential may be realized as thunderstorms move into an area of steeper low-level lapse rates across the central High Plains by late this afternoon and early evening, especially if any small clusters can form. The severe potential along much of the length of the front in the northern Plains and upper MS Valley appears rather conditional. While large-scale ascent associated with the approaching upper trough should gradually overspread the warm sector by late afternoon/early evening, most guidance continues to suggest that a cap and substantial MLCIN will hinder robust convection from developing through much of the day. Even so, sufficient instability and shear should be in place along/ahead of the front to support an isolated hail/wind threat if thunderstorms can form and be sustained through the evening and early overnight period. The post-frontal regime across much of MT into ND and western SD appears unlikely to support severe convection. Accordingly, the Marginal Risk has been trimmed southward to account for recent guidance and observational trends. ..Gleason/Leitman.. 09/04/2024 Read more

000
ABPZ20 KNHC 041144
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Wed Sep 4 2024

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

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

$$
Forecaster Blake

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0310 AM CDT Wed Sep 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... ...D4/Saturday - D5/Sunday: Northeast/Mid Atlantic... An amplifying trough is forecast to evolve into a rather deep mid/upper-level cyclone over parts of Ontario into the eastern Great Lakes region on Saturday, and then begin moving eastward on Sunday. Uncertainty remains regarding the intensity/location of related surface cyclogenesis, and the timing of an attendant cold front into parts of the Northeast and Mid Atlantic. There will be some potential for low-level moisture to be drawn northward in advance of the cold front, though instability will likely remain weak. If adequate buoyancy can develop, then increasing flow fields could support some increase in severe potential across parts of the Mid Atlantic and Northeast on D4/Saturday. Uncertainty regarding frontal position increases into D5/Sunday, though some guidance suggests potential for frontal convection to develop across parts of New England before moving offshore. ...D6/Monday - D8/Wednesday... The deep trough over the eastern CONUS is generally forecast to weaken and move offshore early next week. Farther west, an upper ridge is forecast to amplify over the Southwest, while an upper trough deepens over the eastern Pacific and eventually begins to impinge upon the Pacific Coast. A persistent surface ridge over the East is expected to keep richer low-level moisture confined to near the Gulf Coast, which will tend to limit moisture return and severe-thunderstorm potential across much of the CONUS. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0310 AM CDT Wed Sep 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... ...D4/Saturday - D5/Sunday: Northeast/Mid Atlantic... An amplifying trough is forecast to evolve into a rather deep mid/upper-level cyclone over parts of Ontario into the eastern Great Lakes region on Saturday, and then begin moving eastward on Sunday. Uncertainty remains regarding the intensity/location of related surface cyclogenesis, and the timing of an attendant cold front into parts of the Northeast and Mid Atlantic. There will be some potential for low-level moisture to be drawn northward in advance of the cold front, though instability will likely remain weak. If adequate buoyancy can develop, then increasing flow fields could support some increase in severe potential across parts of the Mid Atlantic and Northeast on D4/Saturday. Uncertainty regarding frontal position increases into D5/Sunday, though some guidance suggests potential for frontal convection to develop across parts of New England before moving offshore. ...D6/Monday - D8/Wednesday... The deep trough over the eastern CONUS is generally forecast to weaken and move offshore early next week. Farther west, an upper ridge is forecast to amplify over the Southwest, while an upper trough deepens over the eastern Pacific and eventually begins to impinge upon the Pacific Coast. A persistent surface ridge over the East is expected to keep richer low-level moisture confined to near the Gulf Coast, which will tend to limit moisture return and severe-thunderstorm potential across much of the CONUS. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0310 AM CDT Wed Sep 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... ...D4/Saturday - D5/Sunday: Northeast/Mid Atlantic... An amplifying trough is forecast to evolve into a rather deep mid/upper-level cyclone over parts of Ontario into the eastern Great Lakes region on Saturday, and then begin moving eastward on Sunday. Uncertainty remains regarding the intensity/location of related surface cyclogenesis, and the timing of an attendant cold front into parts of the Northeast and Mid Atlantic. There will be some potential for low-level moisture to be drawn northward in advance of the cold front, though instability will likely remain weak. If adequate buoyancy can develop, then increasing flow fields could support some increase in severe potential across parts of the Mid Atlantic and Northeast on D4/Saturday. Uncertainty regarding frontal position increases into D5/Sunday, though some guidance suggests potential for frontal convection to develop across parts of New England before moving offshore. ...D6/Monday - D8/Wednesday... The deep trough over the eastern CONUS is generally forecast to weaken and move offshore early next week. Farther west, an upper ridge is forecast to amplify over the Southwest, while an upper trough deepens over the eastern Pacific and eventually begins to impinge upon the Pacific Coast. A persistent surface ridge over the East is expected to keep richer low-level moisture confined to near the Gulf Coast, which will tend to limit moisture return and severe-thunderstorm potential across much of the CONUS. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0310 AM CDT Wed Sep 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... ...D4/Saturday - D5/Sunday: Northeast/Mid Atlantic... An amplifying trough is forecast to evolve into a rather deep mid/upper-level cyclone over parts of Ontario into the eastern Great Lakes region on Saturday, and then begin moving eastward on Sunday. Uncertainty remains regarding the intensity/location of related surface cyclogenesis, and the timing of an attendant cold front into parts of the Northeast and Mid Atlantic. There will be some potential for low-level moisture to be drawn northward in advance of the cold front, though instability will likely remain weak. If adequate buoyancy can develop, then increasing flow fields could support some increase in severe potential across parts of the Mid Atlantic and Northeast on D4/Saturday. Uncertainty regarding frontal position increases into D5/Sunday, though some guidance suggests potential for frontal convection to develop across parts of New England before moving offshore. ...D6/Monday - D8/Wednesday... The deep trough over the eastern CONUS is generally forecast to weaken and move offshore early next week. Farther west, an upper ridge is forecast to amplify over the Southwest, while an upper trough deepens over the eastern Pacific and eventually begins to impinge upon the Pacific Coast. A persistent surface ridge over the East is expected to keep richer low-level moisture confined to near the Gulf Coast, which will tend to limit moisture return and severe-thunderstorm potential across much of the CONUS. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0310 AM CDT Wed Sep 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... ...D4/Saturday - D5/Sunday: Northeast/Mid Atlantic... An amplifying trough is forecast to evolve into a rather deep mid/upper-level cyclone over parts of Ontario into the eastern Great Lakes region on Saturday, and then begin moving eastward on Sunday. Uncertainty remains regarding the intensity/location of related surface cyclogenesis, and the timing of an attendant cold front into parts of the Northeast and Mid Atlantic. There will be some potential for low-level moisture to be drawn northward in advance of the cold front, though instability will likely remain weak. If adequate buoyancy can develop, then increasing flow fields could support some increase in severe potential across parts of the Mid Atlantic and Northeast on D4/Saturday. Uncertainty regarding frontal position increases into D5/Sunday, though some guidance suggests potential for frontal convection to develop across parts of New England before moving offshore. ...D6/Monday - D8/Wednesday... The deep trough over the eastern CONUS is generally forecast to weaken and move offshore early next week. Farther west, an upper ridge is forecast to amplify over the Southwest, while an upper trough deepens over the eastern Pacific and eventually begins to impinge upon the Pacific Coast. A persistent surface ridge over the East is expected to keep richer low-level moisture confined to near the Gulf Coast, which will tend to limit moisture return and severe-thunderstorm potential across much of the CONUS. Read more