Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1151 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z CORRECTED FOR HEADLINE ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN UTAH...NORTHERN ARIZONA...AND FAR SOUTHEAST NEVADA... An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive 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 1142 AM CDT Sun Jun 16 2024 Valid 161700Z - 171200Z An Elevated risk area has been added for portions of the southern Sierra Nevada and western Transverse Ranges in southern California. RH is somewhat marginal for the area, with a minimum of 15-25% expected. However, strong winds (40-50 mph gusts with higher gusts in mountain gaps), rapid drying of fuels, poor overnight RH recovery, and observed rapid growth of the Post fire indicate the threat for additional fire activity in the area. Otherwise, see the previous discussion for further details. ..Supinie.. 06/16/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Jun 16 2024/ ...Synopsis... A deepening western trough will bring an increase in southwesterly flow across much of the desert Southwest this afternoon. Fuels in this region have seen significant drying after several days of warm and dry conditions. Guidance indicates fuels in this region are critically dry, with recent ERCs data indicating 90th percentile for dryness across much of northern and central Arizona. This is further supported by active recent fire activity in this region. Relative humidity reductions to 5-10 percent will overlap sustained winds 15-20 mph across central/northern Arizona, southern Utah, and far southeastern Nevada where a Critical delineation was maintained with this outlook. Outside of this region, a more broad area of Elevated fire weather conditions will be possible across much of central/southern Utah into southern Arizona, where there is less confidence is sustained Critical wind speeds. Elevated conditions may also extend into portions of western Nevada in the lee of the Sierras. In this region, afternoon relative humidity reductions to 15-20 percent will overlap sustained winds 10-15 mph (locally higher) amid modestly receptive 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 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jun 16 2024 Valid 161630Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY AND MIDWEST... ...SUMMARY... Scattered severe storms appear possible across parts of the upper Mississippi Valley late this afternoon, with additional storms likely tonight across the north-central Plains to upper Mississippi Valley. Large hail and damaging winds are the primary risks. A small bowing complex, with mainly a severe/damaging wind threat, may also develop across parts of northern Illinois and vicinity this afternoon. ...Northern/Central Plains to the Upper Midwest/Upper Mississippi Valley... A strong upper trough/low will continue advancing east-northeastward across the northern Plains and Canadian Prairie provinces today. While the primary surface low is expected to remain in central Canada, a weak secondary low should develop generally eastward across MN through this evening in tandem with a cold front. Warm mid-level temperatures associated with a cap should tend to inhibit robust convective development for at least a few more hours into the early afternoon. But, most guidance now does show thunderstorm initiation occurring along the front in northern MN by 20-22Z. There are still concerns/uncertainty with how many intense thunderstorms will be able to form given fairly prevalent cloudiness that should temper daytime heating to some extent. Still, strong deep-layer shear and steepening mid-level lapse rates atop a gradually destabilizing low-level airmass should support a threat for supercells and large hail. Some guidance suggests a fairly quick progression to a MCS, which seems reasonable given the linear forcing of the cold front. If this occurs, then a severe/damaging wind threat may persist through the evening into parts of northern WI and the U.P. of MI. Enough low-level shear is also forecast to support low-level updraft rotation and a tornado or two across this region. A separate area of intense thunderstorm development is possible late this afternoon and early evening along the trailing portion of the cold front in NE/northwest KS and vicinity. If convection can initiate along this boundary, strong instability and modest deep-layer shear would support a threat for mainly multicells posing a risk for severe winds given the well mixed boundary layer forecast. Some hail could also occur with marginal supercell structures. The Slight Risk has been expanded southward across the central Plains to account for this scenario. Otherwise, scattered to numerous elevated thunderstorms are still expected to develop this evening and overnight generally north of the front from eastern WY into NE/SD and southern MN. A strengthening low-level jet in this time frame across these regions and ample deep-layer shear/MUCAPE will easily support supercells and a hail threat with initial development. But, convective mode may quickly become messy, with one or more bows/clusters possible as thunderstorms move eastward across the upper MS Valley overnight. Even though this activity should tend to remain elevated, an isolated severe/damaging wind threat may persist given the strong MUCAPE forecast. ...Northern Illinois/Southern Wisconsin... A well defined MCV remains evident on visible satellite and radar imagery late this morning over northeast MO and southern IA. This feature should continue to track northeastward this afternoon and evening in the modest southwesterly mid-level flow regime across the mid MS Valley/Midwest. Ample daytime heating of a moist low-level airmass should support around 1500-2500 J/kg of MLCAPE by mid afternoon across northern IL and vicinity. Ascent associated with the MCV and its associated mid-level vorticity maximum will likely encourage the development of isolated to widely scattered thunderstorms by 20-22Z. Modest but sufficient deep-layer shear for updraft organization is indicated in various RAP forecast soundings across this region. Scattered severe/damaging winds, along with isolated hail, could occur with a small bowing complex that may develop and move east-northeastward across the Chicago metro area late this afternoon and early evening. Enough low-level shear is also forecast to support a low chance for a tornado or two. Given recent guidance and observational trends, a small Slight Risk has been added across northern IL/southern WI to account for this scenario. ...Southern High Plains... Isolated/widely spaced thunderstorms should form once again this afternoon along the length of a surface lee trough/dryline extending southward across the southern High Plains. Although deep-layer shear is forecast to remain weak, moderate instability and a well-mixed boundary layer should support an isolated threat for severe downdraft winds. Occasional hail may also occur with the more robust cores before convection weakens after sunset. ..Gleason/Bentley.. 06/16/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Sun Jun 16 2024 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... Scattered strong to severe storms are possible across the Upper Mississippi Valley late this afternoon, with additional storms tonight across the north-central Plains to upper Mississippi Valley, with large hail the primary risk. ...Northern/Central Plains to the Upper Great Lakes... Multiple convectively enhanced disturbances/MCVs are noted regionally including across Wisconsin and northern Missouri, embedded with the southern fringe of stronger westerlies aloft located over the Dakotas and Canadian Prairies. Shortwave ridging will generally be noted over the Upper Midwest/upper Mississippi Valley vicinity today, with strong warm-sector ample destabilization in the wake of early day cloud cover and lingering convection. At least isolated/widely scattered late-day thunderstorm redevelopment is plausible, most likely near a surface low/triple point across northern Wisconsin into Upper Michigan, and potentially along the southwestward-extending cold front along the Minnesota/Iowa border vicinity. Large hail and damaging winds are possible. A few severe storms are also possible farther south into areas such as northern Illinois, potentially influenced by an upstream MCV/prior outflow. A greater coverage of potentially severe storms is expected into the evening and beyond, as the low-level jet refocuses and intensifies across the central Plains after sunset. A strong signal for robust elevated convection exists across portions of Nebraska/South Dakota tonight, and this activity should spread northeastward through the overnight hours. Forecast soundings exhibit substantial MUCAPE (in excess of 2000 J/kg), with large hail as the primary concern with the elevated convection. ..Guyer/Leitman.. 06/16/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Sun Jun 16 2024 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... Scattered strong to severe storms are possible across the Upper Mississippi Valley late this afternoon, with additional storms tonight across the north-central Plains to upper Mississippi Valley, with large hail the primary risk. ...Northern/Central Plains to the Upper Great Lakes... Multiple convectively enhanced disturbances/MCVs are noted regionally including across Wisconsin and northern Missouri, embedded with the southern fringe of stronger westerlies aloft located over the Dakotas and Canadian Prairies. Shortwave ridging will generally be noted over the Upper Midwest/upper Mississippi Valley vicinity today, with strong warm-sector ample destabilization in the wake of early day cloud cover and lingering convection. At least isolated/widely scattered late-day thunderstorm redevelopment is plausible, most likely near a surface low/triple point across northern Wisconsin into Upper Michigan, and potentially along the southwestward-extending cold front along the Minnesota/Iowa border vicinity. Large hail and damaging winds are possible. A few severe storms are also possible farther south into areas such as northern Illinois, potentially influenced by an upstream MCV/prior outflow. A greater coverage of potentially severe storms is expected into the evening and beyond, as the low-level jet refocuses and intensifies across the central Plains after sunset. A strong signal for robust elevated convection exists across portions of Nebraska/South Dakota tonight, and this activity should spread northeastward through the overnight hours. Forecast soundings exhibit substantial MUCAPE (in excess of 2000 J/kg), with large hail as the primary concern with the elevated convection. ..Guyer/Leitman.. 06/16/2024 Read more