Severe Storms

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0334 AM CDT Mon May 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... ...Day 4/Thu - Great Plains... A weak upper shortwave trough is expected to spread east from the southern Rockies to the Mid-South on Thursday. As this occurs, a band of enhanced southwesterly flow will overspread parts of OK and the ArkLaTex vicinity. A very moist airmass will be in place as southerly low-level flow maintains upper 60s to low 70s F dewpoints. This will aid in strong to extreme instability across portions of the southern Plains/ArkLaTex. While convective evolution is a bit uncertain, the overall pattern will support severe-thunderstorm potential. A potent shortwave upper trough will move across the northern Rockies to the northern Plains. As this occurs, a surface low will deepen and move from the northern High Plains eastward across the Dakotas. Some severe potential may accompany this system. However, boundary-layer moisture will likely be poor given a prior cold frontal passage and better-quality moisture return only making it as far north as KS or southeast NE. Low-end severe probabilities may be needed in future outlooks, but potential appears too low for a 15 percent delineation at this time. ...Days 5-8/Fri-Mon... Spread among forecast guidance increases Day 5/Fri and beyond. However, a general pattern where subtle upper shortwave troughs emanate from the Rockies into the Plains and central U.S. will likely continue. Forecast guidance varies in timing and location of these features, but at least some severe-thunderstorm potential will be possible from portions of the Plains into the Midwest/Mid-South vicinity through the weekend. Given uncertainty, confidence is too low to introduce 15 percent probabilities for any given area at this time. Read more

MD 0848 CONCERNING SEVERE THUNDERSTORM WATCH 265...266... FOR NORTH-CENTRAL AND NORTHEASTERN OKLAHOMA
Mesoscale Discussion 0848 NWS Storm Prediction Center Norman OK 0142 AM CDT Mon May 20 2024 Areas affected...north-central and northeastern Oklahoma Concerning...Severe Thunderstorm Watch 265...266... Valid 200642Z - 200845Z The severe weather threat for Severe Thunderstorm Watch 265, 266 continues. SUMMARY...Severe-weather risk will continue across portions of north-central and northeastern Oklahoma -- largely within WW 266. DISCUSSION...Latest radar loop shows a cluster of strong/locally severe storms ongoing across north-central and into northeastern Oklahoma -- in the far southeastern corner of soon-to-expire WW 265 and western portions of WW 266. Storms continue to regenerate on the southwestern flank of the convection, resulting in a slow southward drift to the convection. This is occurring as a strong (near 60 kt) southwesterly low-level jet continues to provide a feed of high theta-e air atop low-level convective outflow. With deep-layer shear favorable for organized/rotating storms, expect local/isolated -- but all-hazard -- severe risk to persist for some time. As WW 265 expires, and as storms creep southward with time, local WW extensions may be needed to cover the persistent/evolving risk. ..Goss.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA...OUN... LAT...LON 36199815 36549775 36709727 36379579 35889519 35559583 35489694 35659812 35909821 36199815 Read more

WW 0266 Status Updates
STATUS REPORT ON WW 266 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NNW OKC TO 25 S PNC TO 15 W TUL TO 5 NNW TUL TO 30 NE TUL TO 5 SW JLN. ..GOSS..05/20/24 ATTN...WFO...TSA...OUN... STATUS REPORT FOR WS 266 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OKC001-021-035-037-041-081-083-091-097-101-103-107-111-115-119- 131-143-145-200940- OK . OKLAHOMA COUNTIES INCLUDED ARE ADAIR CHEROKEE CRAIG CREEK DELAWARE LINCOLN LOGAN MCINTOSH MAYES MUSKOGEE NOBLE OKFUSKEE OKMULGEE OTTAWA PAYNE ROGERS TULSA WAGONER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 AM CDT Mon May 20 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO THE OHIO VALLEY... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley vicinity on Wednesday. ...Southern MO/IL into western NY... An upper shortwave trough over the northern/central Plains will shift east to the Upper Midwest/Great Lakes vicinity on Wednesday. This feature, coupled with a southeast-sagging surface front, and convectively enhanced vorticity maxima floating through southwesterly deep-layer flow, will focus thunderstorm potential from portions of southern MO/IL northeast toward the Ohio Valley/lower Great Lakes vicinity. Ahead of the surface boundary, a moist and unstable airmass will be in place (surface dew points in the mid/upper 60s F). Modest midlevel lapse rates around 7 C/km will also overlap this moist boundary layer, aiding in moderate destabilization (MLCAPE to 2000 J/kg). Vertical shear will be modest with northeast extent from IN into western NY, but isolated to widely scattered storms capable of damaging gusts and perhaps some hail will be possible from afternoon into the evening. A corridor of somewhat greater potential may develop across southern MO/IL during the late afternoon into the nighttime hours. Instability and vertical shear will likely be stronger here. Better-organized diurnal convection could congeal into an MCS during the nighttime hours. However, confidence in this scenario is low, precluding higher probabilities at this time. ...OK/TX into AR... An area of broad southwesterly flow will persist across the southern Plains to the Mid-South. A surface front will extend northeast from a low over west-central TX into southern MO. Additionally, a dryline will extend southward from the TX low to the Rio Grande. The evolution of the surface front is a bit uncertain, but this boundary, along with the dryline, may focus thunderstorm development. Capping may suppress convection, but an increasing low-level jet by evening could result in scattered thunderstorms. This activity would pose a risk for hail and damaging gusts, with more conditional tornado risk given capping concerns. One or more clusters or an MCS may spread southeast with time during the evening/overnight. ..Leitman.. 05/20/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0202 AM CDT Mon May 20 2024 Valid 211200Z - 221200Z ...Synopsis... Moderate mid-level flow will remain across the Southwest on Tuesday with single-digit relative humidity across New Mexico. As deep mixing develops during the afternoon, some of this stronger flow will mix to the surface. In addition, a secondary lee cyclone is expected to develop in the TX/OK Panhandle vicinity. This will also aid in stronger surface winds. 15 to 25 mph sustained surface winds are expected across much of New Mexico. Locally critical conditions are probable and a Critical delineation may be needed at a later time, but for now, it is unclear where within the broader Elevated area, the greater threat may be. ..Bentley.. 05/20/2024 ...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 0202 AM CDT Mon May 20 2024 Valid 211200Z - 221200Z ...Synopsis... Moderate mid-level flow will remain across the Southwest on Tuesday with single-digit relative humidity across New Mexico. As deep mixing develops during the afternoon, some of this stronger flow will mix to the surface. In addition, a secondary lee cyclone is expected to develop in the TX/OK Panhandle vicinity. This will also aid in stronger surface winds. 15 to 25 mph sustained surface winds are expected across much of New Mexico. Locally critical conditions are probable and a Critical delineation may be needed at a later time, but for now, it is unclear where within the broader Elevated area, the greater threat may be. ..Bentley.. 05/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more