Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Jul 12 2024 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE UPPER MISSISSIPPI VALLEY AND FAR NORTHERN PLAINS... ...SUMMARY... Multiple clusters of strong to severe thunderstorms are possible across portions of the Northern Plains into the Upper Mississippi Valley on Saturday, with the greatest likelihood from Minnesota into Wisconsin. ...Synopsis... On Saturday, a strong upper high will remain centered over the Four Corners states, with a broad, low-amplitude upper trough across much of southern Canada. In between, a belt of moderate mid to high level winds will exist, stretching from the northern Rockies east/southeastward into the upper Great Lakes. At the surface, a trough will develop roughly from northern MN into central SD and NE, with a weak front pushing south across ND. A moist and unstable air mass will exist near and east of the surface trough in particular, as southwest low-level flow persists. Elsewhere, a compact shortwave trough will move across New England, supporting isolated thunderstorms. However, overall lift and instability with this system do not appear to support severe storms. ...Northern Plains to the upper MS Valley... Multiple zones of severe storms are expected on Saturday, stretching from the northern High Plains toward Lake Michigan. Early-day storms appear likely over parts of northern MN into WI, possibly in MCS format with attendant strong to locally severe gust threat. While these systems typically weaken through midday, some rejuvenation may occur into WI or northern IL as the air mass destabilizes into the diurnal maximum. Behind this early activity, air mass recovery and generally southwest surface winds may support renewed development along western fringes of any existing outflow. Isolated supercells would be possible, with localized/brief hail as winds aloft will be marginal. More likely, damaging winds would occur, as CAPE will be large. Later in the day, strong heating near the surface trough will yield storms over SD and NE, with locally damaging gusts, and perhaps isolated hail. Farther west, another concentrated area of storms is forecast, beginning over northeast MT during the late afternoon, and persisting overnight into the Dakotas and possibly into western MN by Sunday morning. Steep lapse rates and 50 kt effective shear should result in a more favorable supercell environment with hail risk. With time, an MCS is expected with an increasing damaging wind threat overnight. ..Jewell.. 07/12/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1200 PM CDT Fri Jul 12 2024 Valid 121700Z - 131200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEAST OREGON...FAR NORTHWESTERN NEVADA... ...CRITICAL FIRE WEATHER AREA FOR EAST-CENTRAL IDAHO... Elevated to Critical fire weather is expected across portions of the Great Basin region into the Pacific Northwest, with windy/dry conditions as well as several areas of isolated dry thunderstorms. ...East-Central Idaho (Snake River Plain)... A Critical delineation was added into portions of east-central Idaho within the Snake River Plain. Within this region, afternoon relative humidity reductions to 10 percent will overlap sustained west-southwest winds at 15-20 mph amid critically dry fuels. Deterministic guidance is in agreement with this, as well as HREF ensemble guidance which has a 70-80 percent probability of Critical conditions being met for several hours in the late afternoon/early evening. The forecast for Critical conditions across southeastern Oregon into far northwestern Nevada remains unchanged. Areas of isolated dry thunderstorm activity across the Sierra Nevada and Arizona/Utah Strip also remain unchanged with this outlook. See previous discussion for more information. ..Thornton.. 07/12/2024 .PREV DISCUSSION... /ISSUED 0220 AM CDT Fri Jul 12 2024/ ...Synopsis... Fire weather concerns will continue today across portions of the greater Great Basin region. Another day of very hot/dry conditions is expected today as afternoon highs across much of the West climb above 100 F. As of 05 UTC, single-digit RH values were noted across much of the region with little, if any, improvement in surface relative humidity anticipated over the next 24 hours. Despite the hot/dry conditions, an upper ridge centered over southern NV will continue to promote relatively benign winds for most locations, with the exception of the northern Great Basin where gradient winds on the periphery of the ridge will be slightly stronger. Isolated dry thunderstorms will also pose a fire weather concern across parts of the lower CO River Valley and along the Sierra Nevada. ...Southeast OR into southern WY... A low-amplitude mid-level impulse is noted in early-morning water-vapor imagery approaching the Pacific Northwest. Stronger mid-level flow associated with this feature should overspread the Cascades and northern Rockies through the day, leading to modest surface pressure falls across eastern OR/WA into western ID as well as along the northern High Plains. Low-level winds should strengthen to between 15-20 mph within a belt stretching from southern OR into southern ID and southern WY. Active fire behavior over the past 24 hours across east-central OR (even the absence of substantial winds) suggests that fuels are very receptive to fire spread, so the combination of very dry and breezy conditions will support elevated to critical fire weather. A Critical risk area has been introduced for portions of southeast OR into adjacent areas of northwest NV and far northeast CA where ensemble guidance shows a reasonably strong signal (70% probability in latest HREF and NBM guidance) for sustained winds between 20-25 mph and the potential for gusts up to 35 mph. ...Lower CO River Valley into the Sierra Nevada... 00 UTC soundings sampled a plume of 0.5-0.9 inch precipitable water values across the Four Corners region into southern CA. Recent GOES imagery shows this plume gradually migrating west/northwestward along the southern/southwestern side of the upper ridge. Steep mid-level lapse rates across the region coupled with deep boundary-layer mixing should support meager, but sufficient, buoyancy for convection. Thunderstorm coverage should be fairly isolated and tied to terrain features, as orographic ascent drives thunderstorm development around peak heating. However, dry lightning appears probable with any convection that can develop given the very dry low-level conditions, and should pose a fire weather concern given antecedent dry fuels. ...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 1200 PM CDT Fri Jul 12 2024 Valid 121700Z - 131200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEAST OREGON...FAR NORTHWESTERN NEVADA... ...CRITICAL FIRE WEATHER AREA FOR EAST-CENTRAL IDAHO... Elevated to Critical fire weather is expected across portions of the Great Basin region into the Pacific Northwest, with windy/dry conditions as well as several areas of isolated dry thunderstorms. ...East-Central Idaho (Snake River Plain)... A Critical delineation was added into portions of east-central Idaho within the Snake River Plain. Within this region, afternoon relative humidity reductions to 10 percent will overlap sustained west-southwest winds at 15-20 mph amid critically dry fuels. Deterministic guidance is in agreement with this, as well as HREF ensemble guidance which has a 70-80 percent probability of Critical conditions being met for several hours in the late afternoon/early evening. The forecast for Critical conditions across southeastern Oregon into far northwestern Nevada remains unchanged. Areas of isolated dry thunderstorm activity across the Sierra Nevada and Arizona/Utah Strip also remain unchanged with this outlook. See previous discussion for more information. ..Thornton.. 07/12/2024 .PREV DISCUSSION... /ISSUED 0220 AM CDT Fri Jul 12 2024/ ...Synopsis... Fire weather concerns will continue today across portions of the greater Great Basin region. Another day of very hot/dry conditions is expected today as afternoon highs across much of the West climb above 100 F. As of 05 UTC, single-digit RH values were noted across much of the region with little, if any, improvement in surface relative humidity anticipated over the next 24 hours. Despite the hot/dry conditions, an upper ridge centered over southern NV will continue to promote relatively benign winds for most locations, with the exception of the northern Great Basin where gradient winds on the periphery of the ridge will be slightly stronger. Isolated dry thunderstorms will also pose a fire weather concern across parts of the lower CO River Valley and along the Sierra Nevada. ...Southeast OR into southern WY... A low-amplitude mid-level impulse is noted in early-morning water-vapor imagery approaching the Pacific Northwest. Stronger mid-level flow associated with this feature should overspread the Cascades and northern Rockies through the day, leading to modest surface pressure falls across eastern OR/WA into western ID as well as along the northern High Plains. Low-level winds should strengthen to between 15-20 mph within a belt stretching from southern OR into southern ID and southern WY. Active fire behavior over the past 24 hours across east-central OR (even the absence of substantial winds) suggests that fuels are very receptive to fire spread, so the combination of very dry and breezy conditions will support elevated to critical fire weather. A Critical risk area has been introduced for portions of southeast OR into adjacent areas of northwest NV and far northeast CA where ensemble guidance shows a reasonably strong signal (70% probability in latest HREF and NBM guidance) for sustained winds between 20-25 mph and the potential for gusts up to 35 mph. ...Lower CO River Valley into the Sierra Nevada... 00 UTC soundings sampled a plume of 0.5-0.9 inch precipitable water values across the Four Corners region into southern CA. Recent GOES imagery shows this plume gradually migrating west/northwestward along the southern/southwestern side of the upper ridge. Steep mid-level lapse rates across the region coupled with deep boundary-layer mixing should support meager, but sufficient, buoyancy for convection. Thunderstorm coverage should be fairly isolated and tied to terrain features, as orographic ascent drives thunderstorm development around peak heating. However, dry lightning appears probable with any convection that can develop given the very dry low-level conditions, and should pose a fire weather concern given antecedent dry fuels. ...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 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri Jul 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...AND THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Northern Plains... Broad diffluent northwesterly mid-level flow is present today across the northern Plains states. Full sunshine over the region will result in hot surface temperatures and inverted-v thermodynamic profiles from eastern MT/WY into the western Dakotas. Most morning CAM solutions suggest scattered high-based thunderstorm development by late afternoon, with activity spreading slowly eastward through the evening. Locally gusty/damaging winds are the main concern with these storms. Greater instability exists farther east in ND/SD/NE but will remain capped in most areas, unless congealing outflow from the west can intercept the higher theta-e air with some risk of wind/hail in the strongest cells. ...Southern MO/IL... Morning visible satellite imagery shows a remnant MCV over southern MO tracking slowly eastward. Ample low-level moisture and CAPE ahead of this system will likely result in scattered afternoon thunderstorms. Winds aloft are relatively weak, and convection should remain rather disorganized. However, the strongest storms could pose a risk of locally gusty winds. ..Hart/Barnes.. 07/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0755 AM CDT Fri Jul 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO LOWER OHIO VALLEY...AND OVER THE NORTHERN AND CENTRAL GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Synopsis... Deamplification of the northern-stream pattern is forecast in mid/ upper levels, as a persistent trough over the Great Lakes and vicinity moves eastward and weakens substantially. A height weakness will continue to extend from that area southwestward across the mid Mississippi Valley, Arklatex, and south TX, with several embedded/slow-moving vorticity lobes. Meanwhile, a broad area of difluent, zonal to northwesterly flow should continue over the central/northern Plains region, northeast of a prominent anticyclone shifting slowly eastward across the Great Basin and Four Corners regions. At the surface, the 1Z analysis showed weak lows over northeastern MT and southwestern SD, along a quasistationary to slow-moving warm front drawn from southern AB to western SD, central/southeastern NE, central MO, and southern IL. The slightly better-defined MT low should move slowly eastward to northwestern ND by early evening, while the frontal zone to its southeast drifts eastward and northward over central SD, eastern NE, northeastern KS, and central/ northern MO. A lee trough -- initially drawn from western SD to eastern CO and the TX Panhandle -- should meander erratically near its present position today, with some adjustment by falling pressures related to strong surface heating. ...Northern/central Plains... Isolated to widely scattered thunderstorms are moving southeastward over portions of southeastern SD to central N this morning, in a zone of weak DCVA aloft superimposed on a broader area of low-level warm/moist advection above the surface. While an isolated, marginally severe hail report cannot be ruled out in another couple hours, the overall decreasing trend should continue as the LLJ likewise weakens through the remainder of the morning. Isolated to scattered, high-based thunderstorms are expected to develop over western parts of the outlook area near the lee trough today, within a broad area of strong diurnal heating. Isolated development also may occur farther east near the warm front and greater low-level moisture, though weaker lift and stronger MLCINH are expected in that corridor than near the lee trough. Activity west of the front will move atop a deeply well-mixed boundary layer suitable for strong-severe downdrafts. Surface dewpoints mixing well down into the 40s to mid 50s will result in decreasing MLCAPE as MLCINH also weakens, with around 500-1000 J/kg expected in the most-probable area for storm formation. Buoyancy will increase eastward as mixing weakens, but capping strengthens, with a corridor of 60s F dewpoints and 2000-3000 J/kg MLCAPE along and just east of the front. Considerable uncertainty exists how much of the lee- trough activity can aggregate cold pools and potentially utilize forced ascent eastward into the greater moisture, for longer and better organization. Outside the lee trough, forcing for convective-scale lift appears nebulous and poorly focused across the region, with considerable uncertainty remaining on preferred potential corridor(s) for greater severe concentration. One possibility is closer to a northern- stream mid/upper trough north of the international border, but still with uncertainty on the southern extent into the CONUS of any resulting MCS. These uncertainties are reflected in a wide range of convective distributions and intensities across the various convection-allowing guidance, as well as implied from precip fields in the deterministic synoptic models and their ensembles. As such, a broad marginal area is maintained for this outlook cycle, with embedded upgrade(s) possible if mesoscale trends and 12Z/later guidance come into clearer focus. ...Ozarks to lower Ohio Valley... Isolated to widely scattered, non-severe thunderstorms are ongoing over parts of southern MO, northwestern AR and extreme eastern OK, in a field of low-level WAA and weak DCVA. A related increase in convective coverage and intensity is possible farther east and southeast across portions of this region as the foregoing boundary layer diurnally destabilizes, with marginally severe gusts or hail possible in the strongest cells. One of the vorticity lobes embedded in the height weakness aloft, over eastern KS to central/eastern MO, is being enhanced by an MCV from prior/overnight convection now over southwestern MO. This feature will move slowly eastward today and may contribute to relatively maximized thunderstorm coverage in an increasingly unstable airmass from the Ozarks to lower Ohio Valley this afternoon. Rich low-level moisture (surface dewpoints commonly upper 60s to low 70s F) and diurnal heating should offset modest mid/upper-level lapse rates to yield peak MLCAPE in the 2000-3000 J/kg range. Weak low/middle-level flow and modest shear should limit organization enough that severe potential should remain isolated and poorly organized. ..Edwards/Broyles.. 07/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0755 AM CDT Fri Jul 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO LOWER OHIO VALLEY...AND OVER THE NORTHERN AND CENTRAL GREAT PLAINS... ...SUMMARY... Isolated severe wind and hail will be possible this afternoon from the Ozarks to lower Ohio Valley, and over the northern and central Great Plains from late afternoon into tonight. ...Synopsis... Deamplification of the northern-stream pattern is forecast in mid/ upper levels, as a persistent trough over the Great Lakes and vicinity moves eastward and weakens substantially. A height weakness will continue to extend from that area southwestward across the mid Mississippi Valley, Arklatex, and south TX, with several embedded/slow-moving vorticity lobes. Meanwhile, a broad area of difluent, zonal to northwesterly flow should continue over the central/northern Plains region, northeast of a prominent anticyclone shifting slowly eastward across the Great Basin and Four Corners regions. At the surface, the 1Z analysis showed weak lows over northeastern MT and southwestern SD, along a quasistationary to slow-moving warm front drawn from southern AB to western SD, central/southeastern NE, central MO, and southern IL. The slightly better-defined MT low should move slowly eastward to northwestern ND by early evening, while the frontal zone to its southeast drifts eastward and northward over central SD, eastern NE, northeastern KS, and central/ northern MO. A lee trough -- initially drawn from western SD to eastern CO and the TX Panhandle -- should meander erratically near its present position today, with some adjustment by falling pressures related to strong surface heating. ...Northern/central Plains... Isolated to widely scattered thunderstorms are moving southeastward over portions of southeastern SD to central N this morning, in a zone of weak DCVA aloft superimposed on a broader area of low-level warm/moist advection above the surface. While an isolated, marginally severe hail report cannot be ruled out in another couple hours, the overall decreasing trend should continue as the LLJ likewise weakens through the remainder of the morning. Isolated to scattered, high-based thunderstorms are expected to develop over western parts of the outlook area near the lee trough today, within a broad area of strong diurnal heating. Isolated development also may occur farther east near the warm front and greater low-level moisture, though weaker lift and stronger MLCINH are expected in that corridor than near the lee trough. Activity west of the front will move atop a deeply well-mixed boundary layer suitable for strong-severe downdrafts. Surface dewpoints mixing well down into the 40s to mid 50s will result in decreasing MLCAPE as MLCINH also weakens, with around 500-1000 J/kg expected in the most-probable area for storm formation. Buoyancy will increase eastward as mixing weakens, but capping strengthens, with a corridor of 60s F dewpoints and 2000-3000 J/kg MLCAPE along and just east of the front. Considerable uncertainty exists how much of the lee- trough activity can aggregate cold pools and potentially utilize forced ascent eastward into the greater moisture, for longer and better organization. Outside the lee trough, forcing for convective-scale lift appears nebulous and poorly focused across the region, with considerable uncertainty remaining on preferred potential corridor(s) for greater severe concentration. One possibility is closer to a northern- stream mid/upper trough north of the international border, but still with uncertainty on the southern extent into the CONUS of any resulting MCS. These uncertainties are reflected in a wide range of convective distributions and intensities across the various convection-allowing guidance, as well as implied from precip fields in the deterministic synoptic models and their ensembles. As such, a broad marginal area is maintained for this outlook cycle, with embedded upgrade(s) possible if mesoscale trends and 12Z/later guidance come into clearer focus. ...Ozarks to lower Ohio Valley... Isolated to widely scattered, non-severe thunderstorms are ongoing over parts of southern MO, northwestern AR and extreme eastern OK, in a field of low-level WAA and weak DCVA. A related increase in convective coverage and intensity is possible farther east and southeast across portions of this region as the foregoing boundary layer diurnally destabilizes, with marginally severe gusts or hail possible in the strongest cells. One of the vorticity lobes embedded in the height weakness aloft, over eastern KS to central/eastern MO, is being enhanced by an MCV from prior/overnight convection now over southwestern MO. This feature will move slowly eastward today and may contribute to relatively maximized thunderstorm coverage in an increasingly unstable airmass from the Ozarks to lower Ohio Valley this afternoon. Rich low-level moisture (surface dewpoints commonly upper 60s to low 70s F) and diurnal heating should offset modest mid/upper-level lapse rates to yield peak MLCAPE in the 2000-3000 J/kg range. Weak low/middle-level flow and modest shear should limit organization enough that severe potential should remain isolated and poorly organized. ..Edwards/Broyles.. 07/12/2024 Read more