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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Sun May 19 2024 Valid 191300Z - 201200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF KANSAS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EAST-CENTRAL/SOUTHEASTERN FLORIDA... ...SUMMARY... An organized swath of severe thunderstorm wind (potential derecho) is expected mainly across parts of Kansas this afternoon and evening, possibly extending into northern Oklahoma. Gusts of 75-100 mph are possible, along with large hail and a few tornadoes. ...Synopsis... A broad fetch of westerly to southwesterly flow will cover most of the central CONUS. This will persist downstream from a synoptic- scale trough over the Pacific Northwest that should amplify into the Great Basin region through the period. The downstream flow field contains several embedded shortwaves, including a convectively generated perturbation now over parts of KS/NE. This feature should eject northeastward over the upper Mississippi Valley this evening, and away from the main threat area. However, an upstream shortwave trough -- apparent in moisture-channel imagery over the Four Corners region -- will move east-northeastward and influence convective potential over the central Plains this afternoon and evening. Elsewhere aloft, a persistent trough was evident across portions of VA, the Carolinas, GA, and AL, with cyclonic flow downstream over the southern Atlantic Coast and as far south as most of the FL Peninsula. This trough should reach the NC/SC/GA coastlines and northwestern FL by 00Z, and south FL by 12Z tomorrow. The 11Z surface analysis showed a cold front from northeastern ON across Lower MI, western IL, west-central MO and east-central KS, where it is being overtaken by an outflow boundary arching southwestward across south-central KS to the OK Panhandle. The outflow boundary is expected to stall in the next few hours, then shift northward over southern and central KS through the day. A dryline extended from eastern CO across the western TX Panhandle to near LBB, MAF and northern Coahuila. The dryline should mix eastward slightly today, reaching near the KS/CO line and eastern TX Panhandle by mid/late afternoon. Elsewhere, a weak cold front was drawn from a low offshore from NC southwestward over northern FL, and should move slowly southward into central FL today. ...Central Plains... Thunderstorms are expected to develop during mid/late afternoon behind the dryline over the eastern Raton Mesa region, as well as along the dryline itself, and move east-northeastward to eastward into increasing moisture and instability. As they do, some of the activity should aggregate into clusters as smaller-scale outflows combine and enlarge. With supportive internal feedback of an organizing cold pool, associated forced ascent at the front and rear-inflow jet, and supportive midlevel winds for downward momentum transfer, as well as the residual and diurnally destabilized outflow boundary, the overall meso-alpha-scale pattern appears quite suitable for an organized, potentially significant-severe convective-wind swath to result. The most probable corridor for such growth still appears to be across KS in and near the "moderate risk" corridor, driven by wind probabilities. Initially separate dryline development over the northeastern TX Panhandle and northwestern OK may blend into (or even get undercut by outflow from) the broader event as well, after a few hours' discrete time to its south, with a threat of large hail, locally severe gusts and perhaps a tornado or two. Other afternoon development, along the dryline, in the mountains of northern CO and southeastern WY, and over the Black Hills, may move east- northeastward across a narrow moist sector and produce severe gusts and hail into parts of the adjoining High Plains of western NE and the Dakotas. Near and behind the KS-to-Panhandles dryline segment, the storm- initiation environment will be characterized by increasing large-scale ascent and upper divergence ahead of the ejecting Four Corners shortwave trough, as well as strong diurnal heating, mixing and deepening of the boundary layer. Superposition of these effects will lead to nearly 9 deg C/km lapse rates throughout the lower/ middle troposphere, supporting 2000-3000 J/kg MLCAPE just east of the dryline. A deep subcloud layer conducive to strong-severe downdrafts will be available to storms over western KS from the beginning, and should support growth/merger of resultant outflows before activity moves into greater moisture. Forced ascent of the moist boundary layer should help to sustain the forward-propagating complex into strengthening nocturnal MLCINH at least across eastern KS, and perhaps into parts of the lower Missouri Valley, before it weakens tonight. ...FL... Scattered thunderstorms should develop this afternoon near the I-95 corridor and roughly between MIA and the Space Coast, along and south of a weak cold front. Organized multicells and a few supercells are possible, offering large hail and damaging to locally severe gusts before they move offshore. An active Atlantic sea-breeze pattern will be augmented by mid/upper support preceding the trough aloft. Strong diurnal heating, a deep troposphere and rich low-level moisture (with dewpoints commonly in the 70s F and 16.5-18.5 g/kg mean mixing ratios) will support 2000-3000 J/kg peak MLCAPE. Though weak near-surface winds will limit hodograph size, 30-45 kt effective-shear magnitudes and potential boundary interactions will support storm organization, including supercell potential. ..Edwards/Goss.. 05/19/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Sun May 19 2024 Valid 191300Z - 201200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF KANSAS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EAST-CENTRAL/SOUTHEASTERN FLORIDA... ...SUMMARY... An organized swath of severe thunderstorm wind (potential derecho) is expected mainly across parts of Kansas this afternoon and evening, possibly extending into northern Oklahoma. Gusts of 75-100 mph are possible, along with large hail and a few tornadoes. ...Synopsis... A broad fetch of westerly to southwesterly flow will cover most of the central CONUS. This will persist downstream from a synoptic- scale trough over the Pacific Northwest that should amplify into the Great Basin region through the period. The downstream flow field contains several embedded shortwaves, including a convectively generated perturbation now over parts of KS/NE. This feature should eject northeastward over the upper Mississippi Valley this evening, and away from the main threat area. However, an upstream shortwave trough -- apparent in moisture-channel imagery over the Four Corners region -- will move east-northeastward and influence convective potential over the central Plains this afternoon and evening. Elsewhere aloft, a persistent trough was evident across portions of VA, the Carolinas, GA, and AL, with cyclonic flow downstream over the southern Atlantic Coast and as far south as most of the FL Peninsula. This trough should reach the NC/SC/GA coastlines and northwestern FL by 00Z, and south FL by 12Z tomorrow. The 11Z surface analysis showed a cold front from northeastern ON across Lower MI, western IL, west-central MO and east-central KS, where it is being overtaken by an outflow boundary arching southwestward across south-central KS to the OK Panhandle. The outflow boundary is expected to stall in the next few hours, then shift northward over southern and central KS through the day. A dryline extended from eastern CO across the western TX Panhandle to near LBB, MAF and northern Coahuila. The dryline should mix eastward slightly today, reaching near the KS/CO line and eastern TX Panhandle by mid/late afternoon. Elsewhere, a weak cold front was drawn from a low offshore from NC southwestward over northern FL, and should move slowly southward into central FL today. ...Central Plains... Thunderstorms are expected to develop during mid/late afternoon behind the dryline over the eastern Raton Mesa region, as well as along the dryline itself, and move east-northeastward to eastward into increasing moisture and instability. As they do, some of the activity should aggregate into clusters as smaller-scale outflows combine and enlarge. With supportive internal feedback of an organizing cold pool, associated forced ascent at the front and rear-inflow jet, and supportive midlevel winds for downward momentum transfer, as well as the residual and diurnally destabilized outflow boundary, the overall meso-alpha-scale pattern appears quite suitable for an organized, potentially significant-severe convective-wind swath to result. The most probable corridor for such growth still appears to be across KS in and near the "moderate risk" corridor, driven by wind probabilities. Initially separate dryline development over the northeastern TX Panhandle and northwestern OK may blend into (or even get undercut by outflow from) the broader event as well, after a few hours' discrete time to its south, with a threat of large hail, locally severe gusts and perhaps a tornado or two. Other afternoon development, along the dryline, in the mountains of northern CO and southeastern WY, and over the Black Hills, may move east- northeastward across a narrow moist sector and produce severe gusts and hail into parts of the adjoining High Plains of western NE and the Dakotas. Near and behind the KS-to-Panhandles dryline segment, the storm- initiation environment will be characterized by increasing large-scale ascent and upper divergence ahead of the ejecting Four Corners shortwave trough, as well as strong diurnal heating, mixing and deepening of the boundary layer. Superposition of these effects will lead to nearly 9 deg C/km lapse rates throughout the lower/ middle troposphere, supporting 2000-3000 J/kg MLCAPE just east of the dryline. A deep subcloud layer conducive to strong-severe downdrafts will be available to storms over western KS from the beginning, and should support growth/merger of resultant outflows before activity moves into greater moisture. Forced ascent of the moist boundary layer should help to sustain the forward-propagating complex into strengthening nocturnal MLCINH at least across eastern KS, and perhaps into parts of the lower Missouri Valley, before it weakens tonight. ...FL... Scattered thunderstorms should develop this afternoon near the I-95 corridor and roughly between MIA and the Space Coast, along and south of a weak cold front. Organized multicells and a few supercells are possible, offering large hail and damaging to locally severe gusts before they move offshore. An active Atlantic sea-breeze pattern will be augmented by mid/upper support preceding the trough aloft. Strong diurnal heating, a deep troposphere and rich low-level moisture (with dewpoints commonly in the 70s F and 16.5-18.5 g/kg mean mixing ratios) will support 2000-3000 J/kg peak MLCAPE. Though weak near-surface winds will limit hodograph size, 30-45 kt effective-shear magnitudes and potential boundary interactions will support storm organization, including supercell potential. ..Edwards/Goss.. 05/19/2024 Read more

000
ABPZ20 KNHC 191113
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sun May 19 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Reinhart

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... ...Day 4/Wed - Southern Plains to the Ohio Valley... An upper low over the Upper Midwest will develop east/northeast across the Great Lakes and Ontario on Wednesday. A broad area of enhanced mid/upper southwesterly flow will persist across the region. At the surface, strong low pressure over MN/WI will occlude and slowly pivot north/northeast into Ontario. A cold front will shift east across Lower MI/IL/IN, while the southern extent of this boundary stalls, or returns a bit north from southern MO into OK/northwest TX. Convection may be ongoing Wednesday morning along the cold front, with destabilization ahead of the boundary across the Ohio Valley occurring during the day. Further south, convective evolution is more uncertain. However, a very moist and unstable airmass is expected. Thunderstorms may be ongoing during the morning and persist as an MCS through the afternoon, or convection may develop along a surface dryline or residual outflow. While some uncertainty remains in details, a corridor of severe potential appears likely given the presence of a surface boundary, sufficient vertical shear, and a moist/unstable boundary layer. ...Day 5/Thu - Southern Plains/ArkLaTex and the central Appalachians/Mid-Atlantic vicinity... A subtle upper shortwave impulse is forecast to eject from the southern Rockies/northern Mexico toward the Mid-South vicinity on Thursday. As this occurs, a surface dryline will surge east, becoming positioned from near the OK/TX border southward into central TX by evening. A very moist and unstable airmass will be in place ahead of the dryline and convection is likely. With time an MCS may develop and move southeast across the risk area during the evening hours. Meanwhile an upper low over Quebec and attendant trough will overspread much of the northeastern U.S. on Thursday. A surface cold front is expected to develop southeast across the area and a line of thunderstorms may pose some severe risk to the region. Confidence in the location of 15 percent severe coverage is low, precluding probabilities at this time. ...Days 6-8/Fri-Sun... Lower-amplitude and generally weaker flow is expected across much of the CONUS on Friday and Saturday. A seasonally moist airmass will persist across the southern Plains to the Mid-MS Valley during this time, and a weak shortwave impulse migrating through westerly flow aloft may be a focus for strong to severe storms across parts of the Plains/MO Valley. However, spread among guidance is fairly large and confidence is low. By the end of the period on Sunday, some guidance suggests a strong upper shortwave trough will eject into the southern Plains. However, guidance varies in the timing of this feature (some on Saturday, some on Sunday) as well as in the strength of the trough, resulting in low predictability. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... ...Day 4/Wed - Southern Plains to the Ohio Valley... An upper low over the Upper Midwest will develop east/northeast across the Great Lakes and Ontario on Wednesday. A broad area of enhanced mid/upper southwesterly flow will persist across the region. At the surface, strong low pressure over MN/WI will occlude and slowly pivot north/northeast into Ontario. A cold front will shift east across Lower MI/IL/IN, while the southern extent of this boundary stalls, or returns a bit north from southern MO into OK/northwest TX. Convection may be ongoing Wednesday morning along the cold front, with destabilization ahead of the boundary across the Ohio Valley occurring during the day. Further south, convective evolution is more uncertain. However, a very moist and unstable airmass is expected. Thunderstorms may be ongoing during the morning and persist as an MCS through the afternoon, or convection may develop along a surface dryline or residual outflow. While some uncertainty remains in details, a corridor of severe potential appears likely given the presence of a surface boundary, sufficient vertical shear, and a moist/unstable boundary layer. ...Day 5/Thu - Southern Plains/ArkLaTex and the central Appalachians/Mid-Atlantic vicinity... A subtle upper shortwave impulse is forecast to eject from the southern Rockies/northern Mexico toward the Mid-South vicinity on Thursday. As this occurs, a surface dryline will surge east, becoming positioned from near the OK/TX border southward into central TX by evening. A very moist and unstable airmass will be in place ahead of the dryline and convection is likely. With time an MCS may develop and move southeast across the risk area during the evening hours. Meanwhile an upper low over Quebec and attendant trough will overspread much of the northeastern U.S. on Thursday. A surface cold front is expected to develop southeast across the area and a line of thunderstorms may pose some severe risk to the region. Confidence in the location of 15 percent severe coverage is low, precluding probabilities at this time. ...Days 6-8/Fri-Sun... Lower-amplitude and generally weaker flow is expected across much of the CONUS on Friday and Saturday. A seasonally moist airmass will persist across the southern Plains to the Mid-MS Valley during this time, and a weak shortwave impulse migrating through westerly flow aloft may be a focus for strong to severe storms across parts of the Plains/MO Valley. However, spread among guidance is fairly large and confidence is low. By the end of the period on Sunday, some guidance suggests a strong upper shortwave trough will eject into the southern Plains. However, guidance varies in the timing of this feature (some on Saturday, some on Sunday) as well as in the strength of the trough, resulting in low predictability. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... ...Day 4/Wed - Southern Plains to the Ohio Valley... An upper low over the Upper Midwest will develop east/northeast across the Great Lakes and Ontario on Wednesday. A broad area of enhanced mid/upper southwesterly flow will persist across the region. At the surface, strong low pressure over MN/WI will occlude and slowly pivot north/northeast into Ontario. A cold front will shift east across Lower MI/IL/IN, while the southern extent of this boundary stalls, or returns a bit north from southern MO into OK/northwest TX. Convection may be ongoing Wednesday morning along the cold front, with destabilization ahead of the boundary across the Ohio Valley occurring during the day. Further south, convective evolution is more uncertain. However, a very moist and unstable airmass is expected. Thunderstorms may be ongoing during the morning and persist as an MCS through the afternoon, or convection may develop along a surface dryline or residual outflow. While some uncertainty remains in details, a corridor of severe potential appears likely given the presence of a surface boundary, sufficient vertical shear, and a moist/unstable boundary layer. ...Day 5/Thu - Southern Plains/ArkLaTex and the central Appalachians/Mid-Atlantic vicinity... A subtle upper shortwave impulse is forecast to eject from the southern Rockies/northern Mexico toward the Mid-South vicinity on Thursday. As this occurs, a surface dryline will surge east, becoming positioned from near the OK/TX border southward into central TX by evening. A very moist and unstable airmass will be in place ahead of the dryline and convection is likely. With time an MCS may develop and move southeast across the risk area during the evening hours. Meanwhile an upper low over Quebec and attendant trough will overspread much of the northeastern U.S. on Thursday. A surface cold front is expected to develop southeast across the area and a line of thunderstorms may pose some severe risk to the region. Confidence in the location of 15 percent severe coverage is low, precluding probabilities at this time. ...Days 6-8/Fri-Sun... Lower-amplitude and generally weaker flow is expected across much of the CONUS on Friday and Saturday. A seasonally moist airmass will persist across the southern Plains to the Mid-MS Valley during this time, and a weak shortwave impulse migrating through westerly flow aloft may be a focus for strong to severe storms across parts of the Plains/MO Valley. However, spread among guidance is fairly large and confidence is low. By the end of the period on Sunday, some guidance suggests a strong upper shortwave trough will eject into the southern Plains. However, guidance varies in the timing of this feature (some on Saturday, some on Sunday) as well as in the strength of the trough, resulting in low predictability. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... ...Day 4/Wed - Southern Plains to the Ohio Valley... An upper low over the Upper Midwest will develop east/northeast across the Great Lakes and Ontario on Wednesday. A broad area of enhanced mid/upper southwesterly flow will persist across the region. At the surface, strong low pressure over MN/WI will occlude and slowly pivot north/northeast into Ontario. A cold front will shift east across Lower MI/IL/IN, while the southern extent of this boundary stalls, or returns a bit north from southern MO into OK/northwest TX. Convection may be ongoing Wednesday morning along the cold front, with destabilization ahead of the boundary across the Ohio Valley occurring during the day. Further south, convective evolution is more uncertain. However, a very moist and unstable airmass is expected. Thunderstorms may be ongoing during the morning and persist as an MCS through the afternoon, or convection may develop along a surface dryline or residual outflow. While some uncertainty remains in details, a corridor of severe potential appears likely given the presence of a surface boundary, sufficient vertical shear, and a moist/unstable boundary layer. ...Day 5/Thu - Southern Plains/ArkLaTex and the central Appalachians/Mid-Atlantic vicinity... A subtle upper shortwave impulse is forecast to eject from the southern Rockies/northern Mexico toward the Mid-South vicinity on Thursday. As this occurs, a surface dryline will surge east, becoming positioned from near the OK/TX border southward into central TX by evening. A very moist and unstable airmass will be in place ahead of the dryline and convection is likely. With time an MCS may develop and move southeast across the risk area during the evening hours. Meanwhile an upper low over Quebec and attendant trough will overspread much of the northeastern U.S. on Thursday. A surface cold front is expected to develop southeast across the area and a line of thunderstorms may pose some severe risk to the region. Confidence in the location of 15 percent severe coverage is low, precluding probabilities at this time. ...Days 6-8/Fri-Sun... Lower-amplitude and generally weaker flow is expected across much of the CONUS on Friday and Saturday. A seasonally moist airmass will persist across the southern Plains to the Mid-MS Valley during this time, and a weak shortwave impulse migrating through westerly flow aloft may be a focus for strong to severe storms across parts of the Plains/MO Valley. However, spread among guidance is fairly large and confidence is low. By the end of the period on Sunday, some guidance suggests a strong upper shortwave trough will eject into the southern Plains. However, guidance varies in the timing of this feature (some on Saturday, some on Sunday) as well as in the strength of the trough, resulting in low predictability. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... ...Day 4/Wed - Southern Plains to the Ohio Valley... An upper low over the Upper Midwest will develop east/northeast across the Great Lakes and Ontario on Wednesday. A broad area of enhanced mid/upper southwesterly flow will persist across the region. At the surface, strong low pressure over MN/WI will occlude and slowly pivot north/northeast into Ontario. A cold front will shift east across Lower MI/IL/IN, while the southern extent of this boundary stalls, or returns a bit north from southern MO into OK/northwest TX. Convection may be ongoing Wednesday morning along the cold front, with destabilization ahead of the boundary across the Ohio Valley occurring during the day. Further south, convective evolution is more uncertain. However, a very moist and unstable airmass is expected. Thunderstorms may be ongoing during the morning and persist as an MCS through the afternoon, or convection may develop along a surface dryline or residual outflow. While some uncertainty remains in details, a corridor of severe potential appears likely given the presence of a surface boundary, sufficient vertical shear, and a moist/unstable boundary layer. ...Day 5/Thu - Southern Plains/ArkLaTex and the central Appalachians/Mid-Atlantic vicinity... A subtle upper shortwave impulse is forecast to eject from the southern Rockies/northern Mexico toward the Mid-South vicinity on Thursday. As this occurs, a surface dryline will surge east, becoming positioned from near the OK/TX border southward into central TX by evening. A very moist and unstable airmass will be in place ahead of the dryline and convection is likely. With time an MCS may develop and move southeast across the risk area during the evening hours. Meanwhile an upper low over Quebec and attendant trough will overspread much of the northeastern U.S. on Thursday. A surface cold front is expected to develop southeast across the area and a line of thunderstorms may pose some severe risk to the region. Confidence in the location of 15 percent severe coverage is low, precluding probabilities at this time. ...Days 6-8/Fri-Sun... Lower-amplitude and generally weaker flow is expected across much of the CONUS on Friday and Saturday. A seasonally moist airmass will persist across the southern Plains to the Mid-MS Valley during this time, and a weak shortwave impulse migrating through westerly flow aloft may be a focus for strong to severe storms across parts of the Plains/MO Valley. However, spread among guidance is fairly large and confidence is low. By the end of the period on Sunday, some guidance suggests a strong upper shortwave trough will eject into the southern Plains. However, guidance varies in the timing of this feature (some on Saturday, some on Sunday) as well as in the strength of the trough, resulting in low predictability. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun May 19 2024 Valid 221200Z - 271200Z ...DISCUSSION... ...Day 4/Wed - Southern Plains to the Ohio Valley... An upper low over the Upper Midwest will develop east/northeast across the Great Lakes and Ontario on Wednesday. A broad area of enhanced mid/upper southwesterly flow will persist across the region. At the surface, strong low pressure over MN/WI will occlude and slowly pivot north/northeast into Ontario. A cold front will shift east across Lower MI/IL/IN, while the southern extent of this boundary stalls, or returns a bit north from southern MO into OK/northwest TX. Convection may be ongoing Wednesday morning along the cold front, with destabilization ahead of the boundary across the Ohio Valley occurring during the day. Further south, convective evolution is more uncertain. However, a very moist and unstable airmass is expected. Thunderstorms may be ongoing during the morning and persist as an MCS through the afternoon, or convection may develop along a surface dryline or residual outflow. While some uncertainty remains in details, a corridor of severe potential appears likely given the presence of a surface boundary, sufficient vertical shear, and a moist/unstable boundary layer. ...Day 5/Thu - Southern Plains/ArkLaTex and the central Appalachians/Mid-Atlantic vicinity... A subtle upper shortwave impulse is forecast to eject from the southern Rockies/northern Mexico toward the Mid-South vicinity on Thursday. As this occurs, a surface dryline will surge east, becoming positioned from near the OK/TX border southward into central TX by evening. A very moist and unstable airmass will be in place ahead of the dryline and convection is likely. With time an MCS may develop and move southeast across the risk area during the evening hours. Meanwhile an upper low over Quebec and attendant trough will overspread much of the northeastern U.S. on Thursday. A surface cold front is expected to develop southeast across the area and a line of thunderstorms may pose some severe risk to the region. Confidence in the location of 15 percent severe coverage is low, precluding probabilities at this time. ...Days 6-8/Fri-Sun... Lower-amplitude and generally weaker flow is expected across much of the CONUS on Friday and Saturday. A seasonally moist airmass will persist across the southern Plains to the Mid-MS Valley during this time, and a weak shortwave impulse migrating through westerly flow aloft may be a focus for strong to severe storms across parts of the Plains/MO Valley. However, spread among guidance is fairly large and confidence is low. By the end of the period on Sunday, some guidance suggests a strong upper shortwave trough will eject into the southern Plains. However, guidance varies in the timing of this feature (some on Saturday, some on Sunday) as well as in the strength of the trough, resulting in low predictability. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sun May 19 2024 Valid 211200Z - 221200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN KANSAS TO SOUTHWEST WISCONSIN... ...SUMMARY... A broad area of severe thunderstorm potential is expected from the southern Plains to the upper Great Lakes. The highest concentration of severe storms is expected from eastern Kansas to southwest Wisconsin. Damaging gusts, large hail and a few tornadoes are possible through Monday night. ...Synopsis... A negatively tilted upper shortwave trough is forecast to lift northeast from the central Plains to the upper Great Lakes on Tuesday. As this occurs, a belt of 50-70 kt 850-700 mb southwesterly flow will overspread the Lower MO Valley to Upper Michigan. At the surface, low pressure will deepen and shift northeast from eastern NE/KS during the morning, to Lake Superior by Wednesday morning. A dryline is forecast to extend southward across western OK into southwest TX and will develop east through the afternoon. Further north, a cold front will surge east across IA/northern MO during the evening, becoming positioned from Upper Michigan to northeast IL, then southwest to central OK/northwest TX by Wednesday morning. ...Lower MO Valley to Upper Great Lakes... A warm front will lift north across southern MN into northern WI ahead of the surface low during the day. To the east of the low and eastward-advancing cold front, a broad warm sector with mid/upper 60s F dewpoints is expected. A plume of steep midlevel lapse rates will overspread this moist boundary layer, aiding in moderate to strong destabilization. Initial supercells may be possible, posing a risk for all severe hazards. However, given strong forcing, both large-scale and along the advancing cold front, upscale growth into one or more linear bands/segments is likely. This may transition the main severe risk to swaths of damaging gusts by evening. ...Eastern KS/Southwest MO into OK/Northwest AR... Forcing will be weaker with southward extent into the southern Plains vicinity. However, a very moist and unstable airmass will be in place amid supercell vertical wind profiles. More isolated convection may develop along the dryline during the afternoon in Oklahoma, and along the southern extent of the synoptic cold front across eastern KS. This activity will pose an all-hazards risk, with some potential for upscale growth during the evening, especially with any convection moving out of eastern KS into southwest MO. ...Northwest TX vicinity... A conditional threat will exist southward along the dryline. Forcing will remain weak and capping may ultimately preclude thunderstorm development. Nevertheless, strong heating along the dryline and at least modest low-level convergence may be sufficient to allow for a storm or two during the late afternoon/early evening. ..Leitman.. 05/19/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sun May 19 2024 Valid 211200Z - 221200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN KANSAS TO SOUTHWEST WISCONSIN... ...SUMMARY... A broad area of severe thunderstorm potential is expected from the southern Plains to the upper Great Lakes. The highest concentration of severe storms is expected from eastern Kansas to southwest Wisconsin. Damaging gusts, large hail and a few tornadoes are possible through Monday night. ...Synopsis... A negatively tilted upper shortwave trough is forecast to lift northeast from the central Plains to the upper Great Lakes on Tuesday. As this occurs, a belt of 50-70 kt 850-700 mb southwesterly flow will overspread the Lower MO Valley to Upper Michigan. At the surface, low pressure will deepen and shift northeast from eastern NE/KS during the morning, to Lake Superior by Wednesday morning. A dryline is forecast to extend southward across western OK into southwest TX and will develop east through the afternoon. Further north, a cold front will surge east across IA/northern MO during the evening, becoming positioned from Upper Michigan to northeast IL, then southwest to central OK/northwest TX by Wednesday morning. ...Lower MO Valley to Upper Great Lakes... A warm front will lift north across southern MN into northern WI ahead of the surface low during the day. To the east of the low and eastward-advancing cold front, a broad warm sector with mid/upper 60s F dewpoints is expected. A plume of steep midlevel lapse rates will overspread this moist boundary layer, aiding in moderate to strong destabilization. Initial supercells may be possible, posing a risk for all severe hazards. However, given strong forcing, both large-scale and along the advancing cold front, upscale growth into one or more linear bands/segments is likely. This may transition the main severe risk to swaths of damaging gusts by evening. ...Eastern KS/Southwest MO into OK/Northwest AR... Forcing will be weaker with southward extent into the southern Plains vicinity. However, a very moist and unstable airmass will be in place amid supercell vertical wind profiles. More isolated convection may develop along the dryline during the afternoon in Oklahoma, and along the southern extent of the synoptic cold front across eastern KS. This activity will pose an all-hazards risk, with some potential for upscale growth during the evening, especially with any convection moving out of eastern KS into southwest MO. ...Northwest TX vicinity... A conditional threat will exist southward along the dryline. Forcing will remain weak and capping may ultimately preclude thunderstorm development. Nevertheless, strong heating along the dryline and at least modest low-level convergence may be sufficient to allow for a storm or two during the late afternoon/early evening. ..Leitman.. 05/19/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sun May 19 2024 Valid 211200Z - 221200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN KANSAS TO SOUTHWEST WISCONSIN... ...SUMMARY... A broad area of severe thunderstorm potential is expected from the southern Plains to the upper Great Lakes. The highest concentration of severe storms is expected from eastern Kansas to southwest Wisconsin. Damaging gusts, large hail and a few tornadoes are possible through Monday night. ...Synopsis... A negatively tilted upper shortwave trough is forecast to lift northeast from the central Plains to the upper Great Lakes on Tuesday. As this occurs, a belt of 50-70 kt 850-700 mb southwesterly flow will overspread the Lower MO Valley to Upper Michigan. At the surface, low pressure will deepen and shift northeast from eastern NE/KS during the morning, to Lake Superior by Wednesday morning. A dryline is forecast to extend southward across western OK into southwest TX and will develop east through the afternoon. Further north, a cold front will surge east across IA/northern MO during the evening, becoming positioned from Upper Michigan to northeast IL, then southwest to central OK/northwest TX by Wednesday morning. ...Lower MO Valley to Upper Great Lakes... A warm front will lift north across southern MN into northern WI ahead of the surface low during the day. To the east of the low and eastward-advancing cold front, a broad warm sector with mid/upper 60s F dewpoints is expected. A plume of steep midlevel lapse rates will overspread this moist boundary layer, aiding in moderate to strong destabilization. Initial supercells may be possible, posing a risk for all severe hazards. However, given strong forcing, both large-scale and along the advancing cold front, upscale growth into one or more linear bands/segments is likely. This may transition the main severe risk to swaths of damaging gusts by evening. ...Eastern KS/Southwest MO into OK/Northwest AR... Forcing will be weaker with southward extent into the southern Plains vicinity. However, a very moist and unstable airmass will be in place amid supercell vertical wind profiles. More isolated convection may develop along the dryline during the afternoon in Oklahoma, and along the southern extent of the synoptic cold front across eastern KS. This activity will pose an all-hazards risk, with some potential for upscale growth during the evening, especially with any convection moving out of eastern KS into southwest MO. ...Northwest TX vicinity... A conditional threat will exist southward along the dryline. Forcing will remain weak and capping may ultimately preclude thunderstorm development. Nevertheless, strong heating along the dryline and at least modest low-level convergence may be sufficient to allow for a storm or two during the late afternoon/early evening. ..Leitman.. 05/19/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sun May 19 2024 Valid 211200Z - 221200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN KANSAS TO SOUTHWEST WISCONSIN... ...SUMMARY... A broad area of severe thunderstorm potential is expected from the southern Plains to the upper Great Lakes. The highest concentration of severe storms is expected from eastern Kansas to southwest Wisconsin. Damaging gusts, large hail and a few tornadoes are possible through Monday night. ...Synopsis... A negatively tilted upper shortwave trough is forecast to lift northeast from the central Plains to the upper Great Lakes on Tuesday. As this occurs, a belt of 50-70 kt 850-700 mb southwesterly flow will overspread the Lower MO Valley to Upper Michigan. At the surface, low pressure will deepen and shift northeast from eastern NE/KS during the morning, to Lake Superior by Wednesday morning. A dryline is forecast to extend southward across western OK into southwest TX and will develop east through the afternoon. Further north, a cold front will surge east across IA/northern MO during the evening, becoming positioned from Upper Michigan to northeast IL, then southwest to central OK/northwest TX by Wednesday morning. ...Lower MO Valley to Upper Great Lakes... A warm front will lift north across southern MN into northern WI ahead of the surface low during the day. To the east of the low and eastward-advancing cold front, a broad warm sector with mid/upper 60s F dewpoints is expected. A plume of steep midlevel lapse rates will overspread this moist boundary layer, aiding in moderate to strong destabilization. Initial supercells may be possible, posing a risk for all severe hazards. However, given strong forcing, both large-scale and along the advancing cold front, upscale growth into one or more linear bands/segments is likely. This may transition the main severe risk to swaths of damaging gusts by evening. ...Eastern KS/Southwest MO into OK/Northwest AR... Forcing will be weaker with southward extent into the southern Plains vicinity. However, a very moist and unstable airmass will be in place amid supercell vertical wind profiles. More isolated convection may develop along the dryline during the afternoon in Oklahoma, and along the southern extent of the synoptic cold front across eastern KS. This activity will pose an all-hazards risk, with some potential for upscale growth during the evening, especially with any convection moving out of eastern KS into southwest MO. ...Northwest TX vicinity... A conditional threat will exist southward along the dryline. Forcing will remain weak and capping may ultimately preclude thunderstorm development. Nevertheless, strong heating along the dryline and at least modest low-level convergence may be sufficient to allow for a storm or two during the late afternoon/early evening. ..Leitman.. 05/19/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sun May 19 2024 Valid 211200Z - 221200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN KANSAS TO SOUTHWEST WISCONSIN... ...SUMMARY... A broad area of severe thunderstorm potential is expected from the southern Plains to the upper Great Lakes. The highest concentration of severe storms is expected from eastern Kansas to southwest Wisconsin. Damaging gusts, large hail and a few tornadoes are possible through Monday night. ...Synopsis... A negatively tilted upper shortwave trough is forecast to lift northeast from the central Plains to the upper Great Lakes on Tuesday. As this occurs, a belt of 50-70 kt 850-700 mb southwesterly flow will overspread the Lower MO Valley to Upper Michigan. At the surface, low pressure will deepen and shift northeast from eastern NE/KS during the morning, to Lake Superior by Wednesday morning. A dryline is forecast to extend southward across western OK into southwest TX and will develop east through the afternoon. Further north, a cold front will surge east across IA/northern MO during the evening, becoming positioned from Upper Michigan to northeast IL, then southwest to central OK/northwest TX by Wednesday morning. ...Lower MO Valley to Upper Great Lakes... A warm front will lift north across southern MN into northern WI ahead of the surface low during the day. To the east of the low and eastward-advancing cold front, a broad warm sector with mid/upper 60s F dewpoints is expected. A plume of steep midlevel lapse rates will overspread this moist boundary layer, aiding in moderate to strong destabilization. Initial supercells may be possible, posing a risk for all severe hazards. However, given strong forcing, both large-scale and along the advancing cold front, upscale growth into one or more linear bands/segments is likely. This may transition the main severe risk to swaths of damaging gusts by evening. ...Eastern KS/Southwest MO into OK/Northwest AR... Forcing will be weaker with southward extent into the southern Plains vicinity. However, a very moist and unstable airmass will be in place amid supercell vertical wind profiles. More isolated convection may develop along the dryline during the afternoon in Oklahoma, and along the southern extent of the synoptic cold front across eastern KS. This activity will pose an all-hazards risk, with some potential for upscale growth during the evening, especially with any convection moving out of eastern KS into southwest MO. ...Northwest TX vicinity... A conditional threat will exist southward along the dryline. Forcing will remain weak and capping may ultimately preclude thunderstorm development. Nevertheless, strong heating along the dryline and at least modest low-level convergence may be sufficient to allow for a storm or two during the late afternoon/early evening. ..Leitman.. 05/19/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0218 AM CDT Sun May 19 2024 Valid 201200Z - 211200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO... ...Synopsis... Mid-level flow will start to strengthen on Monday as a subtropical shortwave trough approaches the region. A very deeply mixed airmass (near 500mb) will be in place on Monday. Therefore, some of this stronger mid-level flow should transport to the surface relatively easily. A large portion of the Southwest and into the central Rockies will experience Critical meteorological conditions on Monday. The current Critical outline represents where the driest fuels are present. Some expansion of this Critical area may be needed if guidance comes in stronger with winds and/or if fuels dry significantly in the next 36 hours. Elsewhere, fire weather concerns remain low at this time due to moist fuels and high relative humidity. ..Bentley.. 05/19/2024 ...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 0218 AM CDT Sun May 19 2024 Valid 201200Z - 211200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO... ...Synopsis... Mid-level flow will start to strengthen on Monday as a subtropical shortwave trough approaches the region. A very deeply mixed airmass (near 500mb) will be in place on Monday. Therefore, some of this stronger mid-level flow should transport to the surface relatively easily. A large portion of the Southwest and into the central Rockies will experience Critical meteorological conditions on Monday. The current Critical outline represents where the driest fuels are present. Some expansion of this Critical area may be needed if guidance comes in stronger with winds and/or if fuels dry significantly in the next 36 hours. Elsewhere, fire weather concerns remain low at this time due to moist fuels and high relative humidity. ..Bentley.. 05/19/2024 ...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 0218 AM CDT Sun May 19 2024 Valid 201200Z - 211200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO... ...Synopsis... Mid-level flow will start to strengthen on Monday as a subtropical shortwave trough approaches the region. A very deeply mixed airmass (near 500mb) will be in place on Monday. Therefore, some of this stronger mid-level flow should transport to the surface relatively easily. A large portion of the Southwest and into the central Rockies will experience Critical meteorological conditions on Monday. The current Critical outline represents where the driest fuels are present. Some expansion of this Critical area may be needed if guidance comes in stronger with winds and/or if fuels dry significantly in the next 36 hours. Elsewhere, fire weather concerns remain low at this time due to moist fuels and high relative humidity. ..Bentley.. 05/19/2024 ...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 0218 AM CDT Sun May 19 2024 Valid 201200Z - 211200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO... ...Synopsis... Mid-level flow will start to strengthen on Monday as a subtropical shortwave trough approaches the region. A very deeply mixed airmass (near 500mb) will be in place on Monday. Therefore, some of this stronger mid-level flow should transport to the surface relatively easily. A large portion of the Southwest and into the central Rockies will experience Critical meteorological conditions on Monday. The current Critical outline represents where the driest fuels are present. Some expansion of this Critical area may be needed if guidance comes in stronger with winds and/or if fuels dry significantly in the next 36 hours. Elsewhere, fire weather concerns remain low at this time due to moist fuels and high relative humidity. ..Bentley.. 05/19/2024 ...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 0218 AM CDT Sun May 19 2024 Valid 201200Z - 211200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO... ...Synopsis... Mid-level flow will start to strengthen on Monday as a subtropical shortwave trough approaches the region. A very deeply mixed airmass (near 500mb) will be in place on Monday. Therefore, some of this stronger mid-level flow should transport to the surface relatively easily. A large portion of the Southwest and into the central Rockies will experience Critical meteorological conditions on Monday. The current Critical outline represents where the driest fuels are present. Some expansion of this Critical area may be needed if guidance comes in stronger with winds and/or if fuels dry significantly in the next 36 hours. Elsewhere, fire weather concerns remain low at this time due to moist fuels and high relative humidity. ..Bentley.. 05/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0217 AM CDT Sun May 19 2024 Valid 191200Z - 201200Z ...Synopsis... Mid-level troughing will amplify across the western CONUS today. Meanwhile, a mid-level speed max will accelerate from the Southwest into the southern Plains. As a result, lee cyclogenesis is anticipated in the central High Plains. This will lead to dry and breezy conditions across much of the central CONUS, but especially across the Southwest and into the southern High Plains. Sustained winds of 15 to 25 mph are expected across eastern New Mexico and perhaps into the TX/OK Panhandles and far southeast Colorado where single digit relative humidity is likely. Fuels across eastern New Mexico and vicinity are only marginally dry after recent rainfall, but will continue to dry during the day. Therefore, with low-end Critical meteorological conditions and marginally dry fuels, an Elevated delineation is warranted. ..Bentley.. 05/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more