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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL ROCKIES...CENTRAL HIGH PLAINS...NORTHERN PLAINS...AND THE MIDWEST.... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A broad, positively tilted trough with several embedded shortwave troughs will become more consolidated and start to amplify across the northern Plains on Wednesday and Wednesday night. At the surface, a cold front will move southeast across the northern Plains with scattered thunderstorms possible. The greater thunderstorm coverage is expected during the afternoon/evening across the central Rockies, beneath the coldest air aloft, and across northwest Wisconsin/eastern Minnesota early Thursday morning as the low-level jet intensifies along the frontal zone. ...Central Rockies into the central High Plains... Scattered to widespread thunderstorms are expected across the central Rockies on Wednesday afternoon as cold air aloft (-12C at 500mb) combines with significant heating over the higher terrain. The greatest instability will be near the center of the vorticity maximum/cold air pocket where wind shear will be quite weak. Some wind gusts or isolated large hail will be possible, but a more organized threat seems unlikely. A more favorable wind profile will exist along the southern periphery of this trough from eastern Utah to southern Wyoming and northern Colorado. However, the warmer temperatures aloft within this corridor may limit storm coverage/intensity somewhat. Therefore, a few strong to locally severe storms are possible from southern Montana to northern Colorado, western Nebraska, and southwest South Dakota, however, a displacement between the best instability and wind shear should keep the threat somewhat limited. ...Upper Midwest... A mid-level shortwave trough will eject across the Dakotas, in the vicinity of the cold front, during the day Wednesday. Therefore, a few thunderstorms are possible along the cold front, but a lack of better moisture should mostly limit the daytime thunderstorm threat. However, as the low-level jet strengthens overnight, it will result in some moistening between 850mb and 700mb which will likely result in more widespread thunderstorm development after 06Z. During this period, mid-level flow will also strengthen from around 25 knots to near 35 knots by 12Z. This will improve the shear across the region and therefore, result in some threat for large hail and damaging wind gusts near sunrise as storms develop within a region of moderate instability and 30 to 35 knots of shear. ..Bentley.. 09/03/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL ROCKIES...CENTRAL HIGH PLAINS...NORTHERN PLAINS...AND THE MIDWEST.... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A broad, positively tilted trough with several embedded shortwave troughs will become more consolidated and start to amplify across the northern Plains on Wednesday and Wednesday night. At the surface, a cold front will move southeast across the northern Plains with scattered thunderstorms possible. The greater thunderstorm coverage is expected during the afternoon/evening across the central Rockies, beneath the coldest air aloft, and across northwest Wisconsin/eastern Minnesota early Thursday morning as the low-level jet intensifies along the frontal zone. ...Central Rockies into the central High Plains... Scattered to widespread thunderstorms are expected across the central Rockies on Wednesday afternoon as cold air aloft (-12C at 500mb) combines with significant heating over the higher terrain. The greatest instability will be near the center of the vorticity maximum/cold air pocket where wind shear will be quite weak. Some wind gusts or isolated large hail will be possible, but a more organized threat seems unlikely. A more favorable wind profile will exist along the southern periphery of this trough from eastern Utah to southern Wyoming and northern Colorado. However, the warmer temperatures aloft within this corridor may limit storm coverage/intensity somewhat. Therefore, a few strong to locally severe storms are possible from southern Montana to northern Colorado, western Nebraska, and southwest South Dakota, however, a displacement between the best instability and wind shear should keep the threat somewhat limited. ...Upper Midwest... A mid-level shortwave trough will eject across the Dakotas, in the vicinity of the cold front, during the day Wednesday. Therefore, a few thunderstorms are possible along the cold front, but a lack of better moisture should mostly limit the daytime thunderstorm threat. However, as the low-level jet strengthens overnight, it will result in some moistening between 850mb and 700mb which will likely result in more widespread thunderstorm development after 06Z. During this period, mid-level flow will also strengthen from around 25 knots to near 35 knots by 12Z. This will improve the shear across the region and therefore, result in some threat for large hail and damaging wind gusts near sunrise as storms develop within a region of moderate instability and 30 to 35 knots of shear. ..Bentley.. 09/03/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL ROCKIES...CENTRAL HIGH PLAINS...NORTHERN PLAINS...AND THE MIDWEST.... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A broad, positively tilted trough with several embedded shortwave troughs will become more consolidated and start to amplify across the northern Plains on Wednesday and Wednesday night. At the surface, a cold front will move southeast across the northern Plains with scattered thunderstorms possible. The greater thunderstorm coverage is expected during the afternoon/evening across the central Rockies, beneath the coldest air aloft, and across northwest Wisconsin/eastern Minnesota early Thursday morning as the low-level jet intensifies along the frontal zone. ...Central Rockies into the central High Plains... Scattered to widespread thunderstorms are expected across the central Rockies on Wednesday afternoon as cold air aloft (-12C at 500mb) combines with significant heating over the higher terrain. The greatest instability will be near the center of the vorticity maximum/cold air pocket where wind shear will be quite weak. Some wind gusts or isolated large hail will be possible, but a more organized threat seems unlikely. A more favorable wind profile will exist along the southern periphery of this trough from eastern Utah to southern Wyoming and northern Colorado. However, the warmer temperatures aloft within this corridor may limit storm coverage/intensity somewhat. Therefore, a few strong to locally severe storms are possible from southern Montana to northern Colorado, western Nebraska, and southwest South Dakota, however, a displacement between the best instability and wind shear should keep the threat somewhat limited. ...Upper Midwest... A mid-level shortwave trough will eject across the Dakotas, in the vicinity of the cold front, during the day Wednesday. Therefore, a few thunderstorms are possible along the cold front, but a lack of better moisture should mostly limit the daytime thunderstorm threat. However, as the low-level jet strengthens overnight, it will result in some moistening between 850mb and 700mb which will likely result in more widespread thunderstorm development after 06Z. During this period, mid-level flow will also strengthen from around 25 knots to near 35 knots by 12Z. This will improve the shear across the region and therefore, result in some threat for large hail and damaging wind gusts near sunrise as storms develop within a region of moderate instability and 30 to 35 knots of shear. ..Bentley.. 09/03/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL ROCKIES...CENTRAL HIGH PLAINS...NORTHERN PLAINS...AND THE MIDWEST.... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A broad, positively tilted trough with several embedded shortwave troughs will become more consolidated and start to amplify across the northern Plains on Wednesday and Wednesday night. At the surface, a cold front will move southeast across the northern Plains with scattered thunderstorms possible. The greater thunderstorm coverage is expected during the afternoon/evening across the central Rockies, beneath the coldest air aloft, and across northwest Wisconsin/eastern Minnesota early Thursday morning as the low-level jet intensifies along the frontal zone. ...Central Rockies into the central High Plains... Scattered to widespread thunderstorms are expected across the central Rockies on Wednesday afternoon as cold air aloft (-12C at 500mb) combines with significant heating over the higher terrain. The greatest instability will be near the center of the vorticity maximum/cold air pocket where wind shear will be quite weak. Some wind gusts or isolated large hail will be possible, but a more organized threat seems unlikely. A more favorable wind profile will exist along the southern periphery of this trough from eastern Utah to southern Wyoming and northern Colorado. However, the warmer temperatures aloft within this corridor may limit storm coverage/intensity somewhat. Therefore, a few strong to locally severe storms are possible from southern Montana to northern Colorado, western Nebraska, and southwest South Dakota, however, a displacement between the best instability and wind shear should keep the threat somewhat limited. ...Upper Midwest... A mid-level shortwave trough will eject across the Dakotas, in the vicinity of the cold front, during the day Wednesday. Therefore, a few thunderstorms are possible along the cold front, but a lack of better moisture should mostly limit the daytime thunderstorm threat. However, as the low-level jet strengthens overnight, it will result in some moistening between 850mb and 700mb which will likely result in more widespread thunderstorm development after 06Z. During this period, mid-level flow will also strengthen from around 25 knots to near 35 knots by 12Z. This will improve the shear across the region and therefore, result in some threat for large hail and damaging wind gusts near sunrise as storms develop within a region of moderate instability and 30 to 35 knots of shear. ..Bentley.. 09/03/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Tue Sep 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL ROCKIES...CENTRAL HIGH PLAINS...NORTHERN PLAINS...AND THE MIDWEST.... ...SUMMARY... Isolated strong to severe storms are possible on Wednesday across parts of the central and northern Rockies and Plains into parts of Minnesota. ...Synopsis... A broad, positively tilted trough with several embedded shortwave troughs will become more consolidated and start to amplify across the northern Plains on Wednesday and Wednesday night. At the surface, a cold front will move southeast across the northern Plains with scattered thunderstorms possible. The greater thunderstorm coverage is expected during the afternoon/evening across the central Rockies, beneath the coldest air aloft, and across northwest Wisconsin/eastern Minnesota early Thursday morning as the low-level jet intensifies along the frontal zone. ...Central Rockies into the central High Plains... Scattered to widespread thunderstorms are expected across the central Rockies on Wednesday afternoon as cold air aloft (-12C at 500mb) combines with significant heating over the higher terrain. The greatest instability will be near the center of the vorticity maximum/cold air pocket where wind shear will be quite weak. Some wind gusts or isolated large hail will be possible, but a more organized threat seems unlikely. A more favorable wind profile will exist along the southern periphery of this trough from eastern Utah to southern Wyoming and northern Colorado. However, the warmer temperatures aloft within this corridor may limit storm coverage/intensity somewhat. Therefore, a few strong to locally severe storms are possible from southern Montana to northern Colorado, western Nebraska, and southwest South Dakota, however, a displacement between the best instability and wind shear should keep the threat somewhat limited. ...Upper Midwest... A mid-level shortwave trough will eject across the Dakotas, in the vicinity of the cold front, during the day Wednesday. Therefore, a few thunderstorms are possible along the cold front, but a lack of better moisture should mostly limit the daytime thunderstorm threat. However, as the low-level jet strengthens overnight, it will result in some moistening between 850mb and 700mb which will likely result in more widespread thunderstorm development after 06Z. During this period, mid-level flow will also strengthen from around 25 knots to near 35 knots by 12Z. This will improve the shear across the region and therefore, result in some threat for large hail and damaging wind gusts near sunrise as storms develop within a region of moderate instability and 30 to 35 knots of shear. ..Bentley.. 09/03/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical 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 1143 AM CDT Tue Sep 03 2024 Valid 031700Z - 041200Z No changes are needed to the current D1 Fire Weather outlook. See previous discussion below for more information. ..Thornton.. 09/03/2024 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 03 2024/ ...Synopsis... Fire weather concerns will continue into today across parts of the northern Great Basin/northern Rockies as well as the Plains. The upper trough currently over OR is forecast to slowly shift east over the next 24 hours, reaching the northern Rockies by early Wednesday. As this occurs, breezy surface winds within the dry slot of the maturing low will support dry/windy conditions across parts of NV and ID. Over the Plains, a tightening surface pressure gradient will maintain windy conditions through the afternoon, resulting in areas of elevated to critical fire weather conditions. ...Nevada into Idaho... A pronounced dry slot is developing in low-level water-vapor imagery across the northwestern Great Basin/southern OR as the upper low continues to mature. This dry slot is forecast to spread east through this afternoon, which will limit cloud and precipitation chances for northern NV and central to eastern ID and help support RH reductions into the teens. Numerous lightning strikes have been observed over the past 24 hours across this region with GOES IR imagery showing active large fires as of 05 UTC. This fire activity demonstrates the very receptive nature of the current fuel landscape (with the exception of the few locations that received wetting rainfall), and any holdover fires that resulted from the recent lightning activity may become more active today as west/southwest winds increase by late afternoon. Latest deterministic and ensemble solutions continue to suggest 15-20 mph winds will be common, especially through the Snake River Plain of southern/eastern ID and in the lee of the Independence and Ruby Mountains in northeast NV. A few locations may see periods of critical wind/RH conditions, but recent guidance suggests elevated conditions are more likely. Away from the dry slot, isolated to scattered thunderstorms are expected again today across the broader central/northern Rockies region. Forecast storm motions near 30 knots and PWAT values between 0.6 to 0.8 inches suggest dry lightning strikes are possible. However, higher MLCAPE values and lower LCL heights compared to yesterday (Monday) are mitigating factors for predominantly dry thunderstorms. Additionally, latest guidance shows a better QPF signal compared to previous days, which further limits confidence in the dry lightning threat. While this concern precludes risk highlights, any lightning strike may support fire starts given the very dry fuel conditions (ERCs above the 90th percentile). ...Wyoming into Nebraska and South Dakota... Surface pressure has been steadily falling across western NE/SD over the past 12-24 hours, and is expected to fall further through the afternoon as a lee trough continues to deepen. This will maintain breezy southerly winds across the central Plains as well as strengthen westerly downslope flow across eastern WY this afternoon. Downslope warming/drying will result in another day of 15-20% RH minimums across eastern WY and far western NE/SD. Elevated fire weather conditions appear likely within the downslope regime prior to the arrival of clouds (and potentially showers/thunderstorms) around early evening. To the east, modest moisture return into the Plains is ongoing, which will result in a zonal moisture gradient across the Plains by mid afternoon. Recent solutions suggest that the strongest winds may lie within this moisture gradient, resulting in a somewhat confined corridor of elevated fire weather conditions where 15-25 mph winds (gusting to 30-35 mph at times) will overlap with 15-25% RH values. Although guidance occasionally struggles to accurately capture the degree of boundary-layer mixing within these return flow regimes, latest deterministic solutions appear to be capturing moisture trends well and don't show substantial signs of a moist bias. This lends confidence to the ongoing forecast of predominantly elevated fire weather conditions across the region (although some locations may see periods of critical conditions). ...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 1130 AM CDT Tue Sep 03 2024 Valid 031630Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN ROCKIES/GREAT BASIN AND ADJACENT HIGH PLAINS... ...SUMMARY... Scattered thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin this afternoon may yield an isolated severe risk, before spreading eastward toward the northern High Plains this evening. ...Northern Great Basin/Rockies into the Adjacent High Plains... Visible-satellite imagery this morning shows a smoke-encased mid to upper-level low/vorticity maximum over central ID. This upper feature will move to near southwest MT/eastern ID late tonight. The satellite data late this morning shows agitated cumulus developing immediately ahead of the vorticity max near the ID/MT border, and as large-scale ascent spreads east, additional thunderstorms (widely scattered to scattered coverage) should develop over the higher terrain through early afternoon in tandem with daytime heating. Forecast soundings across southwest MT into northwest WY show 500-1000 J/kg MLCAPE with some elongation of the hodograph. A few of the stronger storms will probably acquire transient supercell characteristics and have an associated hail/wind threat. Some clustering may eventually evolve by early evening as storms move into south-central MT and adjacent parts of northern WY. Somewhat more limited low-level moisture should be present this afternoon farther south into WY and northern UT. Even so, diurnal heating will aid in a deeply mixed boundary layer by this afternoon, and steep mid-level lapse rates are also expected to remain over this region. The net result will be high-based thunderstorms capable of producing isolated severe gusts initially developing across northern UT into far eastern ID, and subsequently moving east-northeastward over WY through the evening. ..Smith/Flournoy/Squitieri.. 09/03/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Tue Sep 03 2024 Valid 031630Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN ROCKIES/GREAT BASIN AND ADJACENT HIGH PLAINS... ...SUMMARY... Scattered thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin this afternoon may yield an isolated severe risk, before spreading eastward toward the northern High Plains this evening. ...Northern Great Basin/Rockies into the Adjacent High Plains... Visible-satellite imagery this morning shows a smoke-encased mid to upper-level low/vorticity maximum over central ID. This upper feature will move to near southwest MT/eastern ID late tonight. The satellite data late this morning shows agitated cumulus developing immediately ahead of the vorticity max near the ID/MT border, and as large-scale ascent spreads east, additional thunderstorms (widely scattered to scattered coverage) should develop over the higher terrain through early afternoon in tandem with daytime heating. Forecast soundings across southwest MT into northwest WY show 500-1000 J/kg MLCAPE with some elongation of the hodograph. A few of the stronger storms will probably acquire transient supercell characteristics and have an associated hail/wind threat. Some clustering may eventually evolve by early evening as storms move into south-central MT and adjacent parts of northern WY. Somewhat more limited low-level moisture should be present this afternoon farther south into WY and northern UT. Even so, diurnal heating will aid in a deeply mixed boundary layer by this afternoon, and steep mid-level lapse rates are also expected to remain over this region. The net result will be high-based thunderstorms capable of producing isolated severe gusts initially developing across northern UT into far eastern ID, and subsequently moving east-northeastward over WY through the evening. ..Smith/Flournoy/Squitieri.. 09/03/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Tue Sep 03 2024 Valid 031630Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN ROCKIES/GREAT BASIN AND ADJACENT HIGH PLAINS... ...SUMMARY... Scattered thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin this afternoon may yield an isolated severe risk, before spreading eastward toward the northern High Plains this evening. ...Northern Great Basin/Rockies into the Adjacent High Plains... Visible-satellite imagery this morning shows a smoke-encased mid to upper-level low/vorticity maximum over central ID. This upper feature will move to near southwest MT/eastern ID late tonight. The satellite data late this morning shows agitated cumulus developing immediately ahead of the vorticity max near the ID/MT border, and as large-scale ascent spreads east, additional thunderstorms (widely scattered to scattered coverage) should develop over the higher terrain through early afternoon in tandem with daytime heating. Forecast soundings across southwest MT into northwest WY show 500-1000 J/kg MLCAPE with some elongation of the hodograph. A few of the stronger storms will probably acquire transient supercell characteristics and have an associated hail/wind threat. Some clustering may eventually evolve by early evening as storms move into south-central MT and adjacent parts of northern WY. Somewhat more limited low-level moisture should be present this afternoon farther south into WY and northern UT. Even so, diurnal heating will aid in a deeply mixed boundary layer by this afternoon, and steep mid-level lapse rates are also expected to remain over this region. The net result will be high-based thunderstorms capable of producing isolated severe gusts initially developing across northern UT into far eastern ID, and subsequently moving east-northeastward over WY through the evening. ..Smith/Flournoy/Squitieri.. 09/03/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Tue Sep 03 2024 Valid 031630Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN ROCKIES/GREAT BASIN AND ADJACENT HIGH PLAINS... ...SUMMARY... Scattered thunderstorms developing across the northern Rockies and adjacent portions of the Great Basin this afternoon may yield an isolated severe risk, before spreading eastward toward the northern High Plains this evening. ...Northern Great Basin/Rockies into the Adjacent High Plains... Visible-satellite imagery this morning shows a smoke-encased mid to upper-level low/vorticity maximum over central ID. This upper feature will move to near southwest MT/eastern ID late tonight. The satellite data late this morning shows agitated cumulus developing immediately ahead of the vorticity max near the ID/MT border, and as large-scale ascent spreads east, additional thunderstorms (widely scattered to scattered coverage) should develop over the higher terrain through early afternoon in tandem with daytime heating. Forecast soundings across southwest MT into northwest WY show 500-1000 J/kg MLCAPE with some elongation of the hodograph. A few of the stronger storms will probably acquire transient supercell characteristics and have an associated hail/wind threat. Some clustering may eventually evolve by early evening as storms move into south-central MT and adjacent parts of northern WY. Somewhat more limited low-level moisture should be present this afternoon farther south into WY and northern UT. Even so, diurnal heating will aid in a deeply mixed boundary layer by this afternoon, and steep mid-level lapse rates are also expected to remain over this region. The net result will be high-based thunderstorms capable of producing isolated severe gusts initially developing across northern UT into far eastern ID, and subsequently moving east-northeastward over WY through the evening. ..Smith/Flournoy/Squitieri.. 09/03/2024 Read more