Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...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 0232 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z The previous forecast (see below) remains on track, and only minor adjustments were made with this update. Confidence in the development of sustained critical conditions is highest over parts of northeastern NM, where the surface pressure gradient will be tightest on the western periphery of a lee cyclone. However, near-normal ERCs across this area (owing to rainfall during the last couple weeks) limits confidence in large-fire potential -- precluding Critical highlights at this time. ..Weinman.. 05/20/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Mon May 20 2024/ ...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. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0851 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR THE MICHIGAN THUMB VICINITY
Mesoscale Discussion 0851 NWS Storm Prediction Center Norman OK 1237 PM CDT Mon May 20 2024 Areas affected...the Michigan Thumb vicinity Concerning...Severe potential...Watch unlikely Valid 201737Z - 201930Z Probability of Watch Issuance...20 percent SUMMARY...Strong to severe storms capable of isolated damaging wind and hail are possible this afternoon. DISCUSSION...A cluster of storms has recently intensified near the Thumb region of Michigan. While low-level moisture is relatively limited, strong heating is occurring downstream of this cluster, supporting MUCAPE of near or above 1000 J/kg. Deep-layer shear is rather modest, but unidirectional southwesterly flow may support some organization with this cluster as it moves northeastward through the afternoon. Steepening low-level lapse rates will support a threat for strong/damaging outflow gusts, while stronger embedded cells may be capable of producing some hail. In addition, isolated strong storm development cannot be ruled out later this afternoon to the southwest of the ongoing cluster, along a trailing surface boundary. ..Dean/Hart.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX... LAT...LON 43018372 43438380 43808339 43948304 43838268 43328254 42908247 42848318 42918375 43018372 Read more

WW 0267 Status Updates
STATUS REPORT ON WW 267 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..05/20/24 ATTN...WFO...LOT...MKX... STATUS REPORT FOR WS 267 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC007-037-089-097-103-111-141-201-202040- IL . ILLINOIS COUNTIES INCLUDED ARE BOONE DE KALB KANE LAKE LEE MCHENRY OGLE WINNEBAGO WIC027-055-059-079-089-101-105-127-131-133-202040- WI . WISCONSIN COUNTIES INCLUDED ARE DODGE JEFFERSON KENOSHA MILWAUKEE OZAUKEE RACINE ROCK WALWORTH WASHINGTON WAUKESHA LMZ644-645-646-740-202040- CW . ADJACENT COASTAL WATERS INCLUDED ARE Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN IOWA...NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI... ...SUMMARY... Severe storms are expected Tuesday across the Midwest, especially including portions of Iowa and Missouri into Wisconsin and western/northern Illinois. Tornadoes (a few strong), damaging wind gusts, and large hail are expected. ...Lower/Middle Missouri Valley to the Upper Great Lakes... A notably strong belt of cyclonically curved westerlies (70+ kt 500 mb) will extend from the south-central Great Plains to the Upper Midwest and Upper Great Lakes on Tuesday, with a lead/convectively augmented shortwave trough likely to spread from the central High Plains toward the Lake Superior vicinity late Tuesday night. An elongated surface low over eastern Nebraska Tuesday morning will deepen and lift northeast to northern Wisconsin/Upper Michigan by evening, with a surface warm front lifting northward ahead of the surface low, although its effective position will likely be influenced by the early day precipitation. Meanwhile, a trailing cold front will surge east across Iowa/eastern Kansas/northern Missouri from mid-afternoon into the evening. Remnant clusters of storms will likely be ongoing Tuesday morning across central/eastern Nebraska, with the possibility of additional storms farther east across southern Iowa/northern Missouri in association with a warm-advection regime. Some key uncertainties persist about the influences of this early day convection, but trends will be for quick air mass recovery given a progressive/highly dynamic pattern. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Significantly strengthening mid-level winds and a diurnally persistent strong low-level jet will support initial supercells capable of large hail and a few tornadoes, including strong (EF2+) tornado potential. But a mixed/transitional mode is expected overall, as upscale growth occurs given the degree of forcing for ascent, with likely evolution into a well-organized/fast-moving QLCS capable of increasingly widespread/intense damaging winds and a continued QLCS-related tornado risk. This scenario currently appears to be most probable across southern/eastern Iowa into northwest Illinois and nearby far northern Missouri. The severe risk will persist into the Upper Great Lakes region and middle Mississippi Valley overnight. ...Southern Plains... Convective coverage will likely decrease with southward extent as large-scale ascent focuses northward toward the Great Lakes. Nevertheless isolated storms are possible into northeast Oklahoma/northwest Arkansas by late afternoon/evening, and more conditionally with southwest extent near a dryline from central Oklahoma into central Texas. Large hail and severe gusts will be possible with this activity. ...Northeast States... A weak upper shortwave trough will move across southern Quebec and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern New York into Maine. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. MLCAPE to around 1000 J/kg and effective shear magnitudes around 35 kt will support organized cells. Elongated hodographs and favorable vertical shear suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Guyer.. 05/20/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN IOWA...NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI... ...SUMMARY... Severe storms are expected Tuesday across the Midwest, especially including portions of Iowa and Missouri into Wisconsin and western/northern Illinois. Tornadoes (a few strong), damaging wind gusts, and large hail are expected. ...Lower/Middle Missouri Valley to the Upper Great Lakes... A notably strong belt of cyclonically curved westerlies (70+ kt 500 mb) will extend from the south-central Great Plains to the Upper Midwest and Upper Great Lakes on Tuesday, with a lead/convectively augmented shortwave trough likely to spread from the central High Plains toward the Lake Superior vicinity late Tuesday night. An elongated surface low over eastern Nebraska Tuesday morning will deepen and lift northeast to northern Wisconsin/Upper Michigan by evening, with a surface warm front lifting northward ahead of the surface low, although its effective position will likely be influenced by the early day precipitation. Meanwhile, a trailing cold front will surge east across Iowa/eastern Kansas/northern Missouri from mid-afternoon into the evening. Remnant clusters of storms will likely be ongoing Tuesday morning across central/eastern Nebraska, with the possibility of additional storms farther east across southern Iowa/northern Missouri in association with a warm-advection regime. Some key uncertainties persist about the influences of this early day convection, but trends will be for quick air mass recovery given a progressive/highly dynamic pattern. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Significantly strengthening mid-level winds and a diurnally persistent strong low-level jet will support initial supercells capable of large hail and a few tornadoes, including strong (EF2+) tornado potential. But a mixed/transitional mode is expected overall, as upscale growth occurs given the degree of forcing for ascent, with likely evolution into a well-organized/fast-moving QLCS capable of increasingly widespread/intense damaging winds and a continued QLCS-related tornado risk. This scenario currently appears to be most probable across southern/eastern Iowa into northwest Illinois and nearby far northern Missouri. The severe risk will persist into the Upper Great Lakes region and middle Mississippi Valley overnight. ...Southern Plains... Convective coverage will likely decrease with southward extent as large-scale ascent focuses northward toward the Great Lakes. Nevertheless isolated storms are possible into northeast Oklahoma/northwest Arkansas by late afternoon/evening, and more conditionally with southwest extent near a dryline from central Oklahoma into central Texas. Large hail and severe gusts will be possible with this activity. ...Northeast States... A weak upper shortwave trough will move across southern Quebec and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern New York into Maine. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. MLCAPE to around 1000 J/kg and effective shear magnitudes around 35 kt will support organized cells. Elongated hodographs and favorable vertical shear suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Guyer.. 05/20/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 PM CDT Mon May 20 2024 Valid 211200Z - 221200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN IOWA...NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI... ...SUMMARY... Severe storms are expected Tuesday across the Midwest, especially including portions of Iowa and Missouri into Wisconsin and western/northern Illinois. Tornadoes (a few strong), damaging wind gusts, and large hail are expected. ...Lower/Middle Missouri Valley to the Upper Great Lakes... A notably strong belt of cyclonically curved westerlies (70+ kt 500 mb) will extend from the south-central Great Plains to the Upper Midwest and Upper Great Lakes on Tuesday, with a lead/convectively augmented shortwave trough likely to spread from the central High Plains toward the Lake Superior vicinity late Tuesday night. An elongated surface low over eastern Nebraska Tuesday morning will deepen and lift northeast to northern Wisconsin/Upper Michigan by evening, with a surface warm front lifting northward ahead of the surface low, although its effective position will likely be influenced by the early day precipitation. Meanwhile, a trailing cold front will surge east across Iowa/eastern Kansas/northern Missouri from mid-afternoon into the evening. Remnant clusters of storms will likely be ongoing Tuesday morning across central/eastern Nebraska, with the possibility of additional storms farther east across southern Iowa/northern Missouri in association with a warm-advection regime. Some key uncertainties persist about the influences of this early day convection, but trends will be for quick air mass recovery given a progressive/highly dynamic pattern. Very steep mid-level lapse rates will overspread the increasingly moist warm sector, supporting aggressive diurnal destabilization especially on the southern fringe of lingering convection/cloud cover. Significantly strengthening mid-level winds and a diurnally persistent strong low-level jet will support initial supercells capable of large hail and a few tornadoes, including strong (EF2+) tornado potential. But a mixed/transitional mode is expected overall, as upscale growth occurs given the degree of forcing for ascent, with likely evolution into a well-organized/fast-moving QLCS capable of increasingly widespread/intense damaging winds and a continued QLCS-related tornado risk. This scenario currently appears to be most probable across southern/eastern Iowa into northwest Illinois and nearby far northern Missouri. The severe risk will persist into the Upper Great Lakes region and middle Mississippi Valley overnight. ...Southern Plains... Convective coverage will likely decrease with southward extent as large-scale ascent focuses northward toward the Great Lakes. Nevertheless isolated storms are possible into northeast Oklahoma/northwest Arkansas by late afternoon/evening, and more conditionally with southwest extent near a dryline from central Oklahoma into central Texas. Large hail and severe gusts will be possible with this activity. ...Northeast States... A weak upper shortwave trough will move across southern Quebec and northern New England. This will result in a band of enhanced westerly deep-layer flow from northern New York into Maine. A seasonally moist airmass will be in place with surface dewpoints into the low 60s F, with strong heating and steepening low-level lapse rates. MLCAPE to around 1000 J/kg and effective shear magnitudes around 35 kt will support organized cells. Elongated hodographs and favorable vertical shear suggest marginally severe hail will be possible along with locally damaging wind gusts. ..Guyer.. 05/20/2024 Read more