Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...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 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...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 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...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 1134 AM CDT Thu Jun 13 2024 Valid 131700Z - 141200Z The main change to the updated Day 1 Fire Weather Outlook was to add isolated dry thunderstorm highlights to portions of central and northern AZ. Fuels across this region are becoming critically receptive to wildfire spread, with ERCs exceeding the 90th percentile over several locations. Thunderstorms are expected to be brief and sparse through much of the afternoon, with a slight increase in coverage possible tonight. While thunderstorm coverage may not reach 10 percent over any short interval of time, the longer-term summation of strikes (wet or dry) over fuels primed for ignitions suggests that isolated dry thunderstorm highlights are warranted. Otherwise, the previous forecast remains on track, with occasionally Elevated dry and breezy conditions still expected over portions of the Lower Colorado River Basin. ..Squitieri.. 06/13/2024 .PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/ ...Synopsis... A midlevel trough will advance eastward across southern CA, while a related belt of moderate/strong southerly flow aloft overspreads western AZ into southern NV and UT. This will promote a tightening surface pressure gradient and 15-20 mph sustained southerly surface winds across these areas. These winds, coupled with a deep/dry boundary layer (single-digit RH) and receptive fuels, will favor elevated to locally critical fire-weather conditions. Additionally, isolated thunderstorms are possible during the late afternoon into the overnight hours across portions of AZ into UT -- aided by ascent preceding the aforementioned midlevel trough. If afternoon thunderstorms can develop, these storms would be high-based in an environment characterized by a deep inverted-V thermodynamic profile -- and isolated lightning-induced ignitions would be possible. However, confidence in afternoon storm development is low owing to very marginal instability, precluding Dry Thunderstorm highlights at this time. Confidence in thunderstorm development is higher during the overnight period, when a mix of wet/dry storms are expected. However, increasing boundary-layer RH and midlevel moisture may temper the overall threat of ignitions. ...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 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jun 13 2024 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR NORTHEAST KANSAS INTO NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN/CENTRAL ILLINOIS... ...SUMMARY... Severe thunderstorms are expected late this afternoon and early evening across parts of southern Iowa into northern Missouri and northern/central Illinois. Very large hail, destructive wind gusts, and a couple of tornadoes all appear possible. A broader corridor of severe hail/wind potential will extend from portions of the southern/central High Plains to the Great Lakes. ...Great Lakes... A mid-level shortwave trough with associated westerly mid/upper-level jet will move eastward across the Upper Midwest and Great Lakes today. An attendant surface cold front will likewise sweep eastward across these regions through this evening, with the primary surface cyclone forecast to remain in Canada. Partly cloudy skies this morning should give way to better opportunity for diurnal heating this afternoon. Increasing low-level convergence along the front, along with ascent associated with shortwave trough/mid-level jet, should encourage convective development along/near the front by mid afternoon across parts of Lower MI into northern IL/IN and vicinity. Sufficient instability and deep-layer shear are forecast to support robust thunderstorms with a threat for scattered damaging winds and severe hail. The magnitude of the severe threat will be dependent on how much instability can develop, with differences remaining in high-resolution guidance regarding both how much convection develops, and how intense it will become. Regardless, some severe threat remains apparent, and the Marginal/Slight Risks have been maintained across this region with minimal changes for this update. ...Mid Mississippi Valley... A surface cold front is progged to sag more slowly south-southeastward across the mid MS Valley today, with better forcing aloft generally remaining to the north across the Upper Midwest and Great Lakes. A rather moist low-level airmass, with surface dewpoints generally in the upper 60s to low 70s, will remain along/south of this boundary across the mid MS Valley. Robust daytime heating of this airmass, along with steep mid-level lapse rates, will promote moderate to strong instability (MLCAPE 2500-3500 J/kg) by mid/late afternoon from southeast NE/northeast KS into southern IA/northern MO and vicinity. Warm mid-level temperatures noted on area 12Z soundings (700 mb temperatures of 13+ C) will likely inhibit robust convective development for much of the day, until surface temperatures reach at least the low 90s and finally erode lingering MLCIN. Explosive thunderstorm development is likely by 20-22Z along/near the front, as strong instability combines with enhanced deep-layer shear to support an threat for multiple intense supercells. Very large hail of at least 2-3 inches in diameter, and perhaps a couple tornadoes, will be a threat with these initially discrete supercells. With mid-level westerly flow largely parallel to the surface boundary, a quick transition/upscale growth into one or more bowing clusters seems likely by early evening. This activity should tend to have a greater threat for severe/damaging winds, including the potential for some significant gusts of 75-80 mph. The severe wind/hail threat should continue in a relatively narrow corridor this evening across the mid MS Valley, before increasing MLCIN and nocturnal cooling gradually reduce the overall severe risk tonight. ...Kansas into the Southern/Central High Plains... A hot and deeply mixed airmass is anticipated along/near the front across KS into the southern/central High Plains. This region will generally be displaced to the south of stronger forcing aloft, and warm mid-level temperatures may inhibit convection for much of the day. Still, most guidance suggests isolated to scattered thunderstorms will develop with a very well mixed boundary layer and steepened low/mid-level lapse rates. Severe/damaging downdraft winds appear to be the main threat with this activity, although some hail may also occur with any marginal supercell structures that can form. Based on latest guidance trends, the Slight Risk has been expanded westward to include more of western KS and eastern CO. Isolated significant severe wind gusts (75+ mph) may occur with any loosely organized clusters across KS. But, weaker deep-layer shear compared with locations farther east suggests the overall severe threat will probably remain fairly isolated. ...South Florida... A loosely organized band of convection is ongoing across parts of south FL. While mid-level lapse rates are expected to remain poor, sufficient instability and deep-layer shear may support occasional strong/gusty winds with the more robust activity this afternoon and early evening. A brief tornado or two may also occur given modestly enhanced low-level flow. ..Gleason/Barnes.. 06/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0715 AM CDT Thu Jun 13 2024 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER PORTIONS OF NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN ILLINOIS... ...SUMMARY... Severe thunderstorms are most likely across southern Iowa into northern portions of Missouri and Illinois during the late afternoon to early evening. Very large hail, destructive wind gusts, and a couple tornadoes are possible. ...Great Lakes... Morning water vapor imagery shows a progressive shortwave trough over the Dakotas, with an associated cluster of showers and thunderstorms over eastern SD. This feature will track eastward through the day, with large scale forcing for ascent overspreading parts of southern WI/northern IL and Lower MI by early afternoon. Strong daytime heating in this area will likely result in intensification of thunderstorms along an approaching cold front, in an environment of steep low and mid level lapse rates and moderate CAPE. Activity will spread across Lake Michigan and southern Lower MI through early evening with a risk of hail and damaging winds. ...Middle MS Valley... The aforementioned surface cold front will extend southwestward across southern IA and into northeast KS by mid afternoon. Strong daytime heating will yield afternoon temperatures in the upper 80s to mid 90s ahead of the front, along with a corridor of dewpoints in the mid-upper 60s. Forecast soundings in this zone show large MLCAPE values over 3000 J/kg along with steep low and mid level lapse rates. Convective initiation along the front may be delayed until late afternoon or early evening due to warm temperatures in the 800-700mb layer, but eventually discrete supercells are expected to form along the front. Storms will track east-southeastward across the ENH risk area posing a risk of very large hail, damaging winds, and perhaps a tornado or two. Upscale organization into one or more bowing structures is also expected this evening with an increased risk of damaging winds. ...Western KS to TX Panhandle... A hot and deeply mixed boundary layer will develop this afternoon from the northeast TX Panhandle into western KS, with temperatures over 100F. Most CAM solutions suggest scattered coverage of high-based thunderstorms in this region. Forecast soundings show inverted-v profiles, but also sufficient winds aloft to pose a risk of locally damaging wind gusts for a few hours during the evening. ..Hart/Bentley.. 06/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0715 AM CDT Thu Jun 13 2024 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER PORTIONS OF NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN ILLINOIS... ...SUMMARY... Severe thunderstorms are most likely across southern Iowa into northern portions of Missouri and Illinois during the late afternoon to early evening. Very large hail, destructive wind gusts, and a couple tornadoes are possible. ...Great Lakes... Morning water vapor imagery shows a progressive shortwave trough over the Dakotas, with an associated cluster of showers and thunderstorms over eastern SD. This feature will track eastward through the day, with large scale forcing for ascent overspreading parts of southern WI/northern IL and Lower MI by early afternoon. Strong daytime heating in this area will likely result in intensification of thunderstorms along an approaching cold front, in an environment of steep low and mid level lapse rates and moderate CAPE. Activity will spread across Lake Michigan and southern Lower MI through early evening with a risk of hail and damaging winds. ...Middle MS Valley... The aforementioned surface cold front will extend southwestward across southern IA and into northeast KS by mid afternoon. Strong daytime heating will yield afternoon temperatures in the upper 80s to mid 90s ahead of the front, along with a corridor of dewpoints in the mid-upper 60s. Forecast soundings in this zone show large MLCAPE values over 3000 J/kg along with steep low and mid level lapse rates. Convective initiation along the front may be delayed until late afternoon or early evening due to warm temperatures in the 800-700mb layer, but eventually discrete supercells are expected to form along the front. Storms will track east-southeastward across the ENH risk area posing a risk of very large hail, damaging winds, and perhaps a tornado or two. Upscale organization into one or more bowing structures is also expected this evening with an increased risk of damaging winds. ...Western KS to TX Panhandle... A hot and deeply mixed boundary layer will develop this afternoon from the northeast TX Panhandle into western KS, with temperatures over 100F. Most CAM solutions suggest scattered coverage of high-based thunderstorms in this region. Forecast soundings show inverted-v profiles, but also sufficient winds aloft to pose a risk of locally damaging wind gusts for a few hours during the evening. ..Hart/Bentley.. 06/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0715 AM CDT Thu Jun 13 2024 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER PORTIONS OF NORTHERN MISSOURI...SOUTHERN IOWA...AND NORTHERN ILLINOIS... ...SUMMARY... Severe thunderstorms are most likely across southern Iowa into northern portions of Missouri and Illinois during the late afternoon to early evening. Very large hail, destructive wind gusts, and a couple tornadoes are possible. ...Great Lakes... Morning water vapor imagery shows a progressive shortwave trough over the Dakotas, with an associated cluster of showers and thunderstorms over eastern SD. This feature will track eastward through the day, with large scale forcing for ascent overspreading parts of southern WI/northern IL and Lower MI by early afternoon. Strong daytime heating in this area will likely result in intensification of thunderstorms along an approaching cold front, in an environment of steep low and mid level lapse rates and moderate CAPE. Activity will spread across Lake Michigan and southern Lower MI through early evening with a risk of hail and damaging winds. ...Middle MS Valley... The aforementioned surface cold front will extend southwestward across southern IA and into northeast KS by mid afternoon. Strong daytime heating will yield afternoon temperatures in the upper 80s to mid 90s ahead of the front, along with a corridor of dewpoints in the mid-upper 60s. Forecast soundings in this zone show large MLCAPE values over 3000 J/kg along with steep low and mid level lapse rates. Convective initiation along the front may be delayed until late afternoon or early evening due to warm temperatures in the 800-700mb layer, but eventually discrete supercells are expected to form along the front. Storms will track east-southeastward across the ENH risk area posing a risk of very large hail, damaging winds, and perhaps a tornado or two. Upscale organization into one or more bowing structures is also expected this evening with an increased risk of damaging winds. ...Western KS to TX Panhandle... A hot and deeply mixed boundary layer will develop this afternoon from the northeast TX Panhandle into western KS, with temperatures over 100F. Most CAM solutions suggest scattered coverage of high-based thunderstorms in this region. Forecast soundings show inverted-v profiles, but also sufficient winds aloft to pose a risk of locally damaging wind gusts for a few hours during the evening. ..Hart/Bentley.. 06/13/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CDT Thu Jun 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... ...Day 5/Monday -- Eastern Dakotas/Minnesota... A southwesterly midlevel jet is forecast to overspread a seasonally moist/unstable environment on Monday. Large-scale ascent will remain somewhat nebulous as the more apparent synoptic upper trough remains over the northern Rockies. However, forecast guidance suggests a lead shortwave impulse may migrate through southwesterly mid/upper flow. Favorable vertical shear will support organized severe storms, though coverage and convective evolution remains uncertain. ...Days 6-8/Tue-Thu... Beyond Day 5/Monday, forecast guidance generally shows an overall slower trend with eastward progress of a western upper trough. Severe potential may increase across portions of the northern/central Plains around Day 6/Tue or Day 7/Wed if the trough ejects east/northeast. If this occurs, enhanced deep-layer southwesterly flow would overspread a seasonally moist and unstable environment ahead of a southeastward-advancing cold front. This overall pattern would support some severe potential somewhere from the northern into central Plains. The GFS suite of guidance is more progressive and favors this scenario. However, the ECMWF maintains a stronger eastern upper ridge with little eastward progression of the western upper trough through mid-week. Nevertheless, a broad area of enhanced deep-layer southwesterly flow will impinge on the northern Plains vicinity, and some severe potential seems probable, but location and timing is too uncertain to include probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0214 AM CDT Thu Jun 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... ...Day 5/Monday -- Eastern Dakotas/Minnesota... A southwesterly midlevel jet is forecast to overspread a seasonally moist/unstable environment on Monday. Large-scale ascent will remain somewhat nebulous as the more apparent synoptic upper trough remains over the northern Rockies. However, forecast guidance suggests a lead shortwave impulse may migrate through southwesterly mid/upper flow. Favorable vertical shear will support organized severe storms, though coverage and convective evolution remains uncertain. ...Days 6-8/Tue-Thu... Beyond Day 5/Monday, forecast guidance generally shows an overall slower trend with eastward progress of a western upper trough. Severe potential may increase across portions of the northern/central Plains around Day 6/Tue or Day 7/Wed if the trough ejects east/northeast. If this occurs, enhanced deep-layer southwesterly flow would overspread a seasonally moist and unstable environment ahead of a southeastward-advancing cold front. This overall pattern would support some severe potential somewhere from the northern into central Plains. The GFS suite of guidance is more progressive and favors this scenario. However, the ECMWF maintains a stronger eastern upper ridge with little eastward progression of the western upper trough through mid-week. Nevertheless, a broad area of enhanced deep-layer southwesterly flow will impinge on the northern Plains vicinity, and some severe potential seems probable, but location and timing is too uncertain to include probabilities. Read more