Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...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 1204 PM CDT Wed Jun 12 2024 Valid 121700Z - 131200Z CORRECTED FOR GRAPHIC. ...Update... Isolated dry thunderstorms may develop this afternoon in and around the Davis and Guadalupe Mountains, and portions of southeastern NM. These regions will reside along the eastern periphery of a mid-level ridge axis. Subtle ascent via moist upslope flow and convergence along quasi-dryline should aid in this development, where modest mid-level moisture atop a deeply mixed lower troposphere will exist. Storm motions near 25 kt should also increase the potential for dry strikes. Otherwise, the forecast remains unchanged. Please see the previous discussion for details regarding the Great Basin region. ..Barnes.. 06/12/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Wed Jun 12 2024/ ...Synopsis... Between a midlevel ridge centered over eastern AZ/western NM and a closed midlevel low off the southern CA coast, a belt of moderate southerly flow will overspread portions of the Desert Southwest into the southern Great Basin. Here, deep boundary-layer mixing into the moderate flow aloft will favor locally breezy/gusty south-southwesterly surface winds and single-digit to lower-teens RH. As a result, locally elevated fire-weather conditions are possible over northern AZ, southwestern UT, and southern NV, given increasingly dry fuels. However, a modest surface pressure gradient and marginal surface winds limit confidence in an appreciable fire-weather threat -- precluding Elevated highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1237 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTH FL
Mesoscale Discussion 1237 NWS Storm Prediction Center Norman OK 1009 AM CDT Wed Jun 12 2024 Areas affected...South FL Concerning...Severe potential...Watch unlikely Valid 121509Z - 121715Z Probability of Watch Issuance...20 percent SUMMARY...Brief tornadoes and isolated damaging gusts are possible across south Florida for the next several hours. DISCUSSION...Recent radar imagery has revealed low-level rotation within some of the shallow, more cellular convection across southern FL, particularly near the intersection of Collier, Broward, and Miami-Dade counties. These showers and thunderstorms are being initiated by warm-air advection, but are quickly becoming surface based with the very moist and uncapped airmass across the region. Buoyancy is modest (i.e. around 1500-2000 J/kg of MLCAPE), promoted by shallow but vertically deep thermodynamic profiles. This buoyancy is more than sufficient for deep updrafts capable of lightning. Additionally, the AMX VAD profiles show notable low-level veering, with 20 to 25 kt of 0-1 km storm-relative helicity sampled recently. There may also be some ambient vertical vorticity within the low-level environment, given the presence of storm outflow and low-level convergence that is occurring, particularly to the south of the main precipitation shield. As result, there is likely a mesoscale corridor of greater tornado potential across from Mainland Monroe County northeastward into southern Palm Beach County. Water-loaded downbursts are also possible across much of south FL. ..Mosier/Goss.. 06/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...KEY...TBW... LAT...LON 25138100 25568138 25868172 26208222 26718212 27158120 27238021 26157992 24998038 25138100 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1131 AM CDT Wed Jun 12 2024 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN MINNESOTA AND ADJACENT NORTHWESTERN WISCONSIN AND WESTERN LAKE SUPERIOR... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Upper Mississippi Valley/Upper Midwest... Bands/clusters of convection are ongoing at this time, from the Minnesota Arrowhead southward across northern Wisconsin, and southwestward across southern Minnesota into the Mid Missouri Valley region. This convection continues moving eastward, toward a less unstable airmass, which should temper severe risk over the next few hours. Greatest potential for a couple of marginally severe storms appears to exist over southwestern Minnesota and adjacent portions of southeastern South Dakota and northwestern Iowa, where the greatest instability resides. Greater severe risk is forecast to evolve later this afternoon, north of the ongoing storms. Here, daytime heating ahead of an advancing cold front (associated with a low-amplitude short-wave trough embedded in fast westerly flow aloft, and moving eastward along the international border) will result in moderate to strong instability (2500 to 3500 J/kg mixed-layer CAPE) within the pre-frontal warm sector. Weakly veering but strengthening flow with height across the region will provide favorable shear for organized/rotating storms. Initial convection -- expected to initiate in the 12/20Z to 12/21Z time frame -- should quickly organize/become supercellular, with very large hail likely to be the initial/primary severe risk. A couple of tornadoes will also be possible, though veered low-level flow should temper overall tornado risk. With time, storms are expected to cluster/grow upscale, with small-scale bowing expected, which should yield a gradual increase in damaging-wind potential. Storms will spread rather quickly eastward/southeastward with time, with some severe risk likely to linger through the evening before gradually diminishing overnight. ...South Florida... Widespread convection is ongoing across southern Florida, within a zone of low-level warm advection south of a weak cold front lying across central portions of the Peninsula. Modest lapse rates aloft, but a very moist/tropical boundary layer is resulting in deep CAPE, which will continue to support the widespread convection. While mid-level flow remains rather weak, flow veers/increases with height through the lower troposphere. This is providing ample shear for generally weak/transient updraft rotation. Given the associated potential for a brief tornado or two, low (2%) tornado probability/MRGL risk is being introduced across portions of South Florida. For additional short-term information, please refer to SWOMCD #1237. ..Goss/Moore.. 06/12/2024 Read more

MD 1236 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEAST NEBRASKA...EASTERN SOUTH DAKOTA...SOUTHWEST MINNESOTA...AND NORTHWEST IOWA
Mesoscale Discussion 1236 NWS Storm Prediction Center Norman OK 0716 AM CDT Wed Jun 12 2024 Areas affected...northeast Nebraska...eastern South Dakota...southwest Minnesota...and northwest Iowa Concerning...Severe potential...Watch unlikely Valid 121216Z - 121345Z Probability of Watch Issuance...20 percent SUMMARY...An isolated large hail threat is expected to continue this morning. DISCUSSION...Ongoing elevated thunderstorm activity across eastern South Dakota, western Minnesota, and northern Nebraska has been somewhat more robust than anticipated, particularly amid relatively weak instability (500 to 1000 J/kg MUCAPE). This is likely aided by the 40 to 45 knot low-level jet which continues to intensify based on the OAX, LNX, and FSD VWP. In addition, strong deep layer shear (50+ knots) supports supercells and a threat for large hail with the more robust/longer-lived updrafts. Storms are forming on the eastern edge of the instability plume and moderately strong storm speeds are leading to them moving east of this better instability. However, some thunderstorms may continue to develop on the western periphery of this ongoing activity where greater instability is present. If storms had a longer residence time before exiting the greater buoyancy, a severe thunderstorm watch may be necessary. However, the threat is expected to remain somewhat isolated and only for a few more hours. Therefore, a watch is not anticipated. ..Bentley/Hart.. 06/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...DMX...FSD...OAX...ABR...LBF...UNR... LAT...LON 45239879 45569648 45359496 44379466 42469539 42149693 42199877 42449920 43149980 43660016 44739973 45239879 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0702 AM CDT Wed Jun 12 2024 Valid 121300Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS PORTIONS OF NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN... ...SUMMARY... Scattered severe thunderstorms capable of very large hail, damaging wind gusts, and a few tornadoes will be possible across parts of the Upper Midwest late afternoon and early evening. ...Southern MN/WI early today... Morning water vapor imagery shows a fast-moving shortwave trough over the western Dakotas. Lift and enhanced low-level thermal/moisture advection ahead of the trough has resulted in scattered thunderstorm development over western MN and eastern SD. These storms may persist through the morning, tracking across central/southern MN by early afternoon with some risk of large hail. Daytime heating and increasing low-level moisture will eventually result in moderate CAPE and a risk of organized strong/severe thunderstorms - mainly from central MN eastward after 18z. These storms may grow upscale and track into central WI before weakening, posing a continued risk of damaging winds and hail. ...Northern MN/WI later today... In the wake of the aforementioned morning convection, strong daytime heating and moisture advection will result in a corridor of moderate CAPE across central/northeast MN by mid/late afternoon. Temperatures west of this area will heating to near 90F, with forecast soundings showing little cap, very steep mid-level lapse rates, and MLCAPE values around 3000 J/kg. Large scale forcing will be subtle, leading to the development of discrete supercells. Several overnight CAM runs suggest intense storms that form will track into the Arrowhead region of MN and areas around Duluth by early evening, posing a risk of very large hail, damaging winds, and a few tornadoes. Forecast soundings show substantial low-level shear with effective SRH values of 300+ m2/s2. It is uncertain how the early storms over southern MN will affect moisture return. If high dewpoint air can make it into the ENH risk area, higher tornado probabilities may become warranted. These storms will likely congeal and spread eastward across northern WI during the evening with a continued risk of damaging winds and some hail. ..Hart/Bentley.. 06/12/2024 Read more