Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1156 PM CST Mon Feb 26 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID MS AND LOWER OH VALLEYS INTO THE SOUTHERN GREAT LAKES.... ...SUMMARY... Scattered strong to severe thunderstorms, associated with large hail (some 2 inches diameter), damaging gusts, and a few tornadoes will be possible from late this afternoon into the evening and overnight, from parts of the mid Mississippi Valley to the Ohio Valley and southern Great Lakes. ...Synopsis... Low-amplitude, split mid-level flow over much of the central and western CONUS will gradually consolidate and amplify through the forecast period, as a northern-stream shortwave trough merges with strong southwesterly flow from the southern stream. Multiple weak perturbations embedded within the increasingly strong southern-stream flow ahead of the main vort max will aid in deepening a broad surface cyclone along a cold front over the northern Plains. As the surface low and trailing front advance, warm advection will draw limited, but sufficient, moisture northward into the lower OH Valley and Great Lakes. Strong to severe thunderstorms are possible ahead of the low and along the trailing front through early Wednesday. ...Mid MS and Lower OH Valley... Early in the forecast period, isolated to widely scattered thunderstorms may be ongoing within a strong low-level warm advection regime over the lower OH Valley. Ahead of the main surge of deeper surface moisture, these storms are expected to remain primarily elevated through the mid morning. Elevated buoyancy, steep lapse rates and sufficient vertical shear for supercells may support a conditional risk for large hail through mid morning. Continued warm advection should gradually transport upper 50s to low 60s F surface dewpoints northward into parts of southern and central IL, IN and western OH by mid afternoon. A diffuse moisture gradient along a surface pressure trough/weak dryline should become established across western/central IL into far eastern MO by late afternoon. Strong surface heating and confluence along this feature may support isolated convective development by 21-00z across central/northern IL. At the same time, warm advection along an expected differential-heating zone near the nose of the returning surface moisture may allow for scattered thunderstorm development across portions of northern IN, southern lower MI and northwestern OH. Model soundings show moderate MLCAPE (1500-2000 J/kg) and strong effective shear of 40-50 kt favorable for supercells. A prominent EML for February, with lapse rates of 8 C/km, will favor strong updrafts with efficient hail growth and a risk for significant hail. Later in the evening, the approach of the deepening mid-level trough and surface pressure falls ahead of the surface low across northern IL will yield increasing mass response across the warm sector. Model soundings show enlarged low-level hodographs potentially supporting a few tornadoes and damaging gusts. As the cold front and low move eastward, additional storm development is possible along the surface pressure trough and the surging cold front across portions of far eastern MO and southern IL. Uncertainty on storm mode and coverage remains fairly high, with some CAM solutions suggesting more isolated development ahead of the line, while other show mostly linear growth along the front. Regardless, these storms should continue eastward overnight across southern IN, northern KY and into southwestern OH with the potential for hail and damaging gusts. Should more discrete development occur and be maintained ahead of the building squall line, increasingly strong low-level shear (0-1km SRH of 250-400 m2/s2) could support a risk for tornadoes. The severe threat should gradually diminish into Wednesday morning as the frontal squall line pushes eastward into parts of eastern OH and the central Appalachians with decreasing buoyancy. ..Lyons/Darrow.. 02/27/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 PM CST Mon Feb 26 2024 Valid 270100Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE OHIO VALLEY AND GREAT LAKES... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...01z update... Mid-level moistening is underway this evening as evidenced by 00z RAOBS across the lower OH River Valley and southern Great Lakes. Isolated thunderstorms are possible as moistening and continued isentropic ascent remove elevated inhibition. Confidence remains low on the coverage of storms, but robust elevated buoyancy (1000-2000 J/kg of MUCAPE) rooted about 850mb and 40-50 kt of effective shear would support a conditional risk for elevated supercells. Updated CAM guidance continues to indicate some potential for isolated stronger storms in one or more clusters near the OH River from 8-12z. Given the risk for hail with any stronger storms able to become established, the MRGL risk will be maintained, with no modification, late tonight into early Tuesday. ...Southwest... Evening water-vapor imagery shows a subtle perturbation within the amplified subtropical jet passing over parts of the Southwest. Weak broad-scale ascent from this feature and diurnal heating has resulted in scattered, low-topped convection with occasional lightning. With generally below 250 J/kg of MUCAPE, updrafts are not expected to be particularly strong or long lived. However, a few of these storms may continue into the evening and early overnight hours across eastern AZ and southwestern NM as ascent shifts eastward. General thunder probabilities have been added, given the potential for weak destabilization and continuation of sporadic lightning downstream late this evening. ..Lyons.. 02/27/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0700 PM CST Mon Feb 26 2024 Valid 270100Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE OHIO VALLEY AND GREAT LAKES... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...01z update... Mid-level moistening is underway this evening as evidenced by 00z RAOBS across the lower OH River Valley and southern Great Lakes. Isolated thunderstorms are possible as moistening and continued isentropic ascent remove elevated inhibition. Confidence remains low on the coverage of storms, but robust elevated buoyancy (1000-2000 J/kg of MUCAPE) rooted about 850mb and 40-50 kt of effective shear would support a conditional risk for elevated supercells. Updated CAM guidance continues to indicate some potential for isolated stronger storms in one or more clusters near the OH River from 8-12z. Given the risk for hail with any stronger storms able to become established, the MRGL risk will be maintained, with no modification, late tonight into early Tuesday. ...Southwest... Evening water-vapor imagery shows a subtle perturbation within the amplified subtropical jet passing over parts of the Southwest. Weak broad-scale ascent from this feature and diurnal heating has resulted in scattered, low-topped convection with occasional lightning. With generally below 250 J/kg of MUCAPE, updrafts are not expected to be particularly strong or long lived. However, a few of these storms may continue into the evening and early overnight hours across eastern AZ and southwestern NM as ascent shifts eastward. General thunder probabilities have been added, given the potential for weak destabilization and continuation of sporadic lightning downstream late this evening. ..Lyons.. 02/27/2024 Read more

No watches are valid as of Mon Feb 26 22:35:02 UTC 2024.

No Mesoscale Discussions are in effect as of Mon Feb 26 22:35:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0308 PM CST Mon Feb 26 2024 Valid 281200Z - 051200Z Large-scale ridging aloft will overspread much of the central U.S. during the middle/latter portions of the week. A southern stream shortwave trough is forecast to eject out of northern Mexico into the southern Plains late Wednesday into Thursday. By early Saturday, a potent upper-level trough will dig into the southwestern U.S. and make quick progress through the Southwest into the southern Plains by Sunday. Strong surface cyclones can be expected in the Plains in association with this upper-level system. ...Southern High Plains... The focus for potentially critical fire weather continues to be focused on the southern High Plains as the next trough approaches the region this coming weekend. Models continue general agreement on the timing and structure of this large-scale feature. Confidence in critical fire weather has increased on Saturday and a 40% area has been added. Sunday continues to appear like the peak intensity of the event. Continued model convergence does suggest that higher probabilities may be needed in the coming days. At this time, there is still enough potential for the timing and/or latitudinal position of the trough to change that confidence in properly placing any increased probabilities is limited. Further, a leading southern stream shortwave trough may produce precipitation in parts of the southern High Plains on Thursday. While amounts may remain minimal to light for some areas, given some remaining dry air near the surface, this also adds to the overall uncertainty. ..Wendt.. 02/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...20Z Update... ...Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ..Mosier.. 02/26/2024 .PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ...Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...20Z Update... ...Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ..Mosier.. 02/26/2024 .PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ...Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...20Z Update... ...Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ..Mosier.. 02/26/2024 .PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ...Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...20Z Update... ...Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ..Mosier.. 02/26/2024 .PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ...Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...20Z Update... ...Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ..Mosier.. 02/26/2024 .PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ...Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ...SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ...20Z Update... ...Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ..Mosier.. 02/26/2024 .PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ...Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1258 PM CST Mon Feb 26 2024 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... The Elevated area has been expanded into parts of central/southern Missouri. Updated fuel information has increased confidence in potential for fire spread. Winds of around 20 mph do appear probable, though RH may only be marginally reduced. The timing of the front should allow for a few hours of these conditions during the afternoon. With regard to potential for sustained critical conditions, western Oklahoma is the most probable per latest ensemble guidance. However, duration is still uncertain enough to withhold Critical highlights. ..Wendt.. 02/26/2024 .PREV DISCUSSION... /ISSUED 0204 AM CST Mon Feb 26 2024/ ...Synopsis... Across the western US, an amplifying Pacific trough will begin to phase with intensifying southern stream flow as it crosses the southern and central Rockies into the Plains. A strong lee low will move over the central Plains with dry and breezy conditions likely behind a trailing dryline/surface pressure trough. Favorable meteorological conditions and at least somewhat receptive fuels should support widespread elevated to near-critical fire-weather concerns over parts of the southern Plains. ...southern Plains... As the aforementioned trough begins to move over the Plains early D2/Tuesday, strong low-level flow is expected to develop by mid morning. Westerly winds of 20-25 mph, with gusts of 30-35 mph, are possible across parts of western and central OK and the TX Panhandle. Despite dry downsloping and the unusually warm temperatures, increasing mid and high-level cloud cover may limit diurnal RH minimums to near 20-25%. Pre-greenup fuels have shown some drying over the previous days, but remain only partially receptive to broader fire spread despite the favorable meteorological conditions. Still, widespread elevated to near/briefly critical fire-weather conditions appear likely. The greatest confidence in potentially longer-lived critical conditions is across parts of western and central OK and the eastern TX Panhandle where the strongest winds are expected to overlap more receptive fuels for the greatest duration. Fire-weather concerns will begin to diminish later in the evening as a cold front rapidly moves south. Strong gusts may persist behind the front along with a rapid wind shift to north/northwesterly. Cooler temperatures and higher RH behind the front should quickly limit sustained fire-weather concerns through the overnight hours. ...Midwest... Farther to the northeast, gusty southwest winds and very warm/dry conditions are expected southwest of the advancing low across parts of MO and western IL. A pronounced low-level thermal ridge overlaying southwest winds of 20-30 mph may support brief elevated or locally critical fire-weather conditions Tuesday afternoon. Area fuels have shown increased dryness over the past several days, but remain partially receptive to fire spread. Thus, confidence in sustained fire-weather conditions is low. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1258 PM CST Mon Feb 26 2024 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... The Elevated area has been expanded into parts of central/southern Missouri. Updated fuel information has increased confidence in potential for fire spread. Winds of around 20 mph do appear probable, though RH may only be marginally reduced. The timing of the front should allow for a few hours of these conditions during the afternoon. With regard to potential for sustained critical conditions, western Oklahoma is the most probable per latest ensemble guidance. However, duration is still uncertain enough to withhold Critical highlights. ..Wendt.. 02/26/2024 .PREV DISCUSSION... /ISSUED 0204 AM CST Mon Feb 26 2024/ ...Synopsis... Across the western US, an amplifying Pacific trough will begin to phase with intensifying southern stream flow as it crosses the southern and central Rockies into the Plains. A strong lee low will move over the central Plains with dry and breezy conditions likely behind a trailing dryline/surface pressure trough. Favorable meteorological conditions and at least somewhat receptive fuels should support widespread elevated to near-critical fire-weather concerns over parts of the southern Plains. ...southern Plains... As the aforementioned trough begins to move over the Plains early D2/Tuesday, strong low-level flow is expected to develop by mid morning. Westerly winds of 20-25 mph, with gusts of 30-35 mph, are possible across parts of western and central OK and the TX Panhandle. Despite dry downsloping and the unusually warm temperatures, increasing mid and high-level cloud cover may limit diurnal RH minimums to near 20-25%. Pre-greenup fuels have shown some drying over the previous days, but remain only partially receptive to broader fire spread despite the favorable meteorological conditions. Still, widespread elevated to near/briefly critical fire-weather conditions appear likely. The greatest confidence in potentially longer-lived critical conditions is across parts of western and central OK and the eastern TX Panhandle where the strongest winds are expected to overlap more receptive fuels for the greatest duration. Fire-weather concerns will begin to diminish later in the evening as a cold front rapidly moves south. Strong gusts may persist behind the front along with a rapid wind shift to north/northwesterly. Cooler temperatures and higher RH behind the front should quickly limit sustained fire-weather concerns through the overnight hours. ...Midwest... Farther to the northeast, gusty southwest winds and very warm/dry conditions are expected southwest of the advancing low across parts of MO and western IL. A pronounced low-level thermal ridge overlaying southwest winds of 20-30 mph may support brief elevated or locally critical fire-weather conditions Tuesday afternoon. Area fuels have shown increased dryness over the past several days, but remain partially receptive to fire spread. Thus, confidence in sustained fire-weather conditions is low. ...Please see www.spc.noaa.gov/fire for graphic product... Read more