Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Tue Feb 27 2024 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST IL AND FAR NORTHWEST IN THIS EVENING...AND ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY THIS EVENING THROUGH TONIGHT.... ...SUMMARY... Severe thunderstorms, associated with large hail, damaging gusts, and tornadoes, some of which may be significant, will be possible from late this afternoon into the overnight, across portions of northeast Illinois and northwest Indiana as well as the Lower and Middle Ohio Valley. ...20Z Update... ...Northern IL/Southern WI This Evening... Recent surface analysis places a low near the IA/MO/IL border intersection. A dryline arcs southeast from this low to near STL and then back southwest into north-central AR. Dewpoints behind this dryline are in the 40s, while dewpoints across much of IL are in the upper 50s/low 60s. A warm front also arcs northeastward from this low to just north of the ORD, then eastward across southern Lake Michigan, and southeastward across northern IN into far west-central OH. General expectation outlined in the previous discussion remains valid, with convective initiation anticipated near this low, with the resulting storms then tracking northeastward in the vicinity of the warm front. It remains uncertain whether or not these storms will be on the warm side of the boundary. Given the kinematic fields, any surface-based storms would likely be supercellular and capable of all severe hazards, including tornadoes. Recent guidance include the 18Z and 19Z WoFS as well as the 12Z MPAS runs all suggest an increasing likelihood for surface-based, warm sector storms. Given these trends, expanded the Enhanced southeastward to include more of northeast IL and far northwest IN and also introduced a 10% significant tornado probability. ...OH Valley This Evening and Overnight... Overall expectation outlined in the previous outlook remains unchanged for tonight across the OH Valley. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. Given the strengthening low-level flow, destructive wind gusts around 75 mph are possible, with a strong tornado or two possible as well. ..Mosier.. 02/27/2024 .PREV DISCUSSION... /ISSUED 1026 AM CST Tue Feb 27 2024/ ...OH Valley... A fast-moving southern-stream shortwave trough over the central Plains will track eastward today and begin affecting parts of MO by late afternoon or early evening. Most 12z guidance suggests that at least isolated thunderstorm development will begin around/after dusk as the large-scale forcing overspreads the northern extent of moist/unstable air mass from southwest MO into southern IL. These storms will intensify and track eastward overnight roughly along the OH river, moving into parts of OH/WV/PA by early morning Wednesday. Initial storms may be discrete, with sufficient vertical shear for supercells structures capable of all severe hazards. As the night progresses, activity will likely evolve into fast-moving bowing structures with an enhanced risk of damaging wind gusts and a few tornadoes. A strong tornado or two cannot be ruled out. Have added an ENH risk area for this scenario overnight. ...IL/WI... A compact surface low is forecast to deepen across eastern IA this afternoon, with a narrow warm sector pulling northward into much of northern IL. Strong forcing near the low and along the associated warm front will lead to intense thunderstorms across portions of northern IL after 22z. Forecast soundings show steep low and mid level lapse rates and sufficient CAPE, along with strong low and deep layer shear profiles. This will be conducive to supercell structures capable of very large hail and damaging winds. There remains uncertainty whether these storms will be in the warm-sector, or will be undercut by nearby cold air. Have upgraded a small part of this area to ENH risk for hail, but there is also concern for tornadoes if the activity remains surface-based. Read more

No Mesoscale Discussions are in effect as of Tue Feb 27 19:16:01 UTC 2024.

MD 0161 CONCERNING SNOW SQUALL FOR EASTERN CO TO NORTHERN NE
Mesoscale Discussion 0161 NWS Storm Prediction Center Norman OK 1012 AM CST Tue Feb 27 2024 Areas affected...Eastern CO to northern NE Concerning...Snow Squall Valid 271612Z - 271915Z SUMMARY...A short-duration moderate to heavy snow band that is effectively producing sporadic snow squall conditions should spread east-southeast into early afternoon across parts of eastern Colorado and northern Nebraska. DISCUSSION...700-mb frontogenetical forcing for ascent has supported a narrow band of moderate to heavy snow across a portion of the Denver Metro Area northeastward into north-central NE, per surface observations and road cameras. The northeast extent of this band is well removed from the surface cold front that is marching south-southeast from IA to north KS and east-central CO. Strong, post-frontal gradient winds are combining with the narrow snow band to produce snow squall-like conditions with substantial reduction in visibility despite the mesoanalysis snow squall parameter holding less than 0.1. The stronger 700-mb frontogenesis is largely expected to shift east in NE and gradually weaken while shifting southeast in eastern CO. This may yield breaks in the ongoing thin band, a scenario supported by recent RRFS guidance. ..Grams.. 02/27/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...OAX...GID...LBF...GLD...PUB...BOU... LAT...LON 40220439 40670277 42470020 43039938 43249835 42959772 42399785 41349895 40180157 39480232 38740295 38480341 38500383 38770443 39260477 40220439 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...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 1213 PM CST Tue Feb 27 2024 Valid 281200Z - 291200Z ...NO CRITICAL AREAS... There continues to be variability in the locations in the vicinity of the Rio Grande Valley that will see the most favorable overlap of lowered RH and stronger winds. Further, winds will be strongest in the morning and will steadily decline into the afternoon. Given these uncertainties, no highlights will be added. However, locally elevated conditions are still expected. ..Wendt.. 02/27/2024 .PREV DISCUSSION... /ISSUED 0159 AM CST Tue Feb 27 2024/ ...Synopsis... An upper trough over the Central US is forecast to amplify significantly as it moves into the northeast Wednesday. Behind the trough a strong cold front will sweep southeastward ushering in a much colder air mass over the western and central US. Behind the front, strong northerly winds are expected over the Plains along with higher relative humidity, limiting the fire-weather threat. One exception, may be across parts of south TX and the Rio Grande Valley. Winds of 20-25 mph may briefly overlap with humidity below 30% over areas of somewhat receptive fuels. However, this is likely to be brief and widespread fire-weather concerns are not expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more