Aggregator

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0312 AM CDT Sat Jun 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...D4/Tuesday: Central Great Plains into the upper Midwest... Some severe-thunderstorm potential may evolve from the central Great Plains into the upper Midwest on Tuesday, along/ahead of a southward-moving cold front. Uncertainty remains regarding storm evolution leading into this period from D3/Monday, with some potential for the cold front to become increasingly displaced from stronger flow aloft. However, moderate to strong buoyancy and at least modest deep-layer shear could support strong to severe storms Tuesday afternoon/evening. ...D5/Wednesday: Central/southern Great Plains into the OH Valley and Northeast... Some threat for strong to severe storms will again be possible near the cold front Wednesday afternoon and evening, which is generally forecast to be draped from the south-central Great Plains northeastward across the OH Valley into parts of the Northeast. There is some potential for a stronger mid/upper-level shortwave trough to interact with the front across the Northeast, though instability may remain somewhat limited. Farther southwest into the Plains, pre-frontal instability will be greater, but deep-layer shear is expected to remain rather weak. ...D6/Thursday - D8/Saturday... Extended-range guidance generally supports potential for a mid/upper-level shortwave trough to amplify and move across the northern CONUS by the end of next week, though there is considerable spread regarding the timing of any such shortwave. While predictability is too low to introduce probabilities at this time, there is potential for an organized severe-thunderstorm threat to evolve somewhere from the northern Plains into the Great Lakes and Northeast, during the Thursday to Saturday time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0312 AM CDT Sat Jun 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...D4/Tuesday: Central Great Plains into the upper Midwest... Some severe-thunderstorm potential may evolve from the central Great Plains into the upper Midwest on Tuesday, along/ahead of a southward-moving cold front. Uncertainty remains regarding storm evolution leading into this period from D3/Monday, with some potential for the cold front to become increasingly displaced from stronger flow aloft. However, moderate to strong buoyancy and at least modest deep-layer shear could support strong to severe storms Tuesday afternoon/evening. ...D5/Wednesday: Central/southern Great Plains into the OH Valley and Northeast... Some threat for strong to severe storms will again be possible near the cold front Wednesday afternoon and evening, which is generally forecast to be draped from the south-central Great Plains northeastward across the OH Valley into parts of the Northeast. There is some potential for a stronger mid/upper-level shortwave trough to interact with the front across the Northeast, though instability may remain somewhat limited. Farther southwest into the Plains, pre-frontal instability will be greater, but deep-layer shear is expected to remain rather weak. ...D6/Thursday - D8/Saturday... Extended-range guidance generally supports potential for a mid/upper-level shortwave trough to amplify and move across the northern CONUS by the end of next week, though there is considerable spread regarding the timing of any such shortwave. While predictability is too low to introduce probabilities at this time, there is potential for an organized severe-thunderstorm threat to evolve somewhere from the northern Plains into the Great Lakes and Northeast, during the Thursday to Saturday time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0312 AM CDT Sat Jun 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...D4/Tuesday: Central Great Plains into the upper Midwest... Some severe-thunderstorm potential may evolve from the central Great Plains into the upper Midwest on Tuesday, along/ahead of a southward-moving cold front. Uncertainty remains regarding storm evolution leading into this period from D3/Monday, with some potential for the cold front to become increasingly displaced from stronger flow aloft. However, moderate to strong buoyancy and at least modest deep-layer shear could support strong to severe storms Tuesday afternoon/evening. ...D5/Wednesday: Central/southern Great Plains into the OH Valley and Northeast... Some threat for strong to severe storms will again be possible near the cold front Wednesday afternoon and evening, which is generally forecast to be draped from the south-central Great Plains northeastward across the OH Valley into parts of the Northeast. There is some potential for a stronger mid/upper-level shortwave trough to interact with the front across the Northeast, though instability may remain somewhat limited. Farther southwest into the Plains, pre-frontal instability will be greater, but deep-layer shear is expected to remain rather weak. ...D6/Thursday - D8/Saturday... Extended-range guidance generally supports potential for a mid/upper-level shortwave trough to amplify and move across the northern CONUS by the end of next week, though there is considerable spread regarding the timing of any such shortwave. While predictability is too low to introduce probabilities at this time, there is potential for an organized severe-thunderstorm threat to evolve somewhere from the northern Plains into the Great Lakes and Northeast, during the Thursday to Saturday time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0312 AM CDT Sat Jun 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... ...D4/Tuesday: Central Great Plains into the upper Midwest... Some severe-thunderstorm potential may evolve from the central Great Plains into the upper Midwest on Tuesday, along/ahead of a southward-moving cold front. Uncertainty remains regarding storm evolution leading into this period from D3/Monday, with some potential for the cold front to become increasingly displaced from stronger flow aloft. However, moderate to strong buoyancy and at least modest deep-layer shear could support strong to severe storms Tuesday afternoon/evening. ...D5/Wednesday: Central/southern Great Plains into the OH Valley and Northeast... Some threat for strong to severe storms will again be possible near the cold front Wednesday afternoon and evening, which is generally forecast to be draped from the south-central Great Plains northeastward across the OH Valley into parts of the Northeast. There is some potential for a stronger mid/upper-level shortwave trough to interact with the front across the Northeast, though instability may remain somewhat limited. Farther southwest into the Plains, pre-frontal instability will be greater, but deep-layer shear is expected to remain rather weak. ...D6/Thursday - D8/Saturday... Extended-range guidance generally supports potential for a mid/upper-level shortwave trough to amplify and move across the northern CONUS by the end of next week, though there is considerable spread regarding the timing of any such shortwave. While predictability is too low to introduce probabilities at this time, there is potential for an organized severe-thunderstorm threat to evolve somewhere from the northern Plains into the Great Lakes and Northeast, during the Thursday to Saturday time frame. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sat Jun 22 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF MN...NORTHWEST WI...WESTERN UPPER MI... ...SUMMARY... Severe thunderstorms are possible on Monday across parts of the northern Great Plains into the upper Mississippi Valley and Great Lakes. ...Northern Great Plains into the upper MS Valley/Great Lakes... Uncertainty remains rather high regarding storm potential on Monday from the northern Great Plains into the upper MS Valley and Great Lakes. However, with some conditional significant-severe potential within a favorable environment, a Slight Risk has been added for parts of MN into northwest WI and western upper MI, where confidence is currently highest in isolated to widely scattered storm coverage. A mid/upper-level shortwave trough and related surface low are forecast to move eastward across parts of SK/MB on Monday. A secondary surface low is forecast to develop along a trailing surface trough/weak cold front across the Dakotas. A surface boundary initially draped roughly from the Ohio Valley northwestward through parts of IA and southeast SD is forecast to move northward as a warm front, potentially reaching parts of central MN and eastern ND by Monday evening. Storm development/evolution across the region remains unclear, with the stronger large-scale ascent expected to remain north of the international border. However, strong to locally extreme instability is expected to develop along/east of the surface trough across the Dakotas, and along and to the south/west of the northward moving warm front. While the warm sector may remain capped for much of the day, at least isolated storm development will be possible near the warm front, and also potentially near the surface trough/cold front. Elevated convection may also develop to the cool side of the warm front, especially during the evening when some intensification of a southwesterly low-level jet is expected. Deep-layer shear will be sufficient for organized convection. Any surface-based supercell development could pose a conditional risk of all severe hazards, including some potential for significant hail and/or wind given the very favorable thermodynamic environment. Depending on the evolution of initial storm development, an MCS could develop and move southeastward along the instability gradient, though this scenario remains rather uncertain at this time. ...Coastal Carolinas... Some guidance suggests a southeastward-moving cold front will slow down or stall across eastern NC/SC, resulting in the potential for scattered thunderstorm development during the afternoon, within a moderately unstable environment. Should this occur, modest northwesterly flow aloft could support sufficient storm organization for an isolated damaging wind and hail threat. This scenario remains uncertain, but severe probabilities may eventually be needed if confidence increases. ..Dean.. 06/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sat Jun 22 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF MN...NORTHWEST WI...WESTERN UPPER MI... ...SUMMARY... Severe thunderstorms are possible on Monday across parts of the northern Great Plains into the upper Mississippi Valley and Great Lakes. ...Northern Great Plains into the upper MS Valley/Great Lakes... Uncertainty remains rather high regarding storm potential on Monday from the northern Great Plains into the upper MS Valley and Great Lakes. However, with some conditional significant-severe potential within a favorable environment, a Slight Risk has been added for parts of MN into northwest WI and western upper MI, where confidence is currently highest in isolated to widely scattered storm coverage. A mid/upper-level shortwave trough and related surface low are forecast to move eastward across parts of SK/MB on Monday. A secondary surface low is forecast to develop along a trailing surface trough/weak cold front across the Dakotas. A surface boundary initially draped roughly from the Ohio Valley northwestward through parts of IA and southeast SD is forecast to move northward as a warm front, potentially reaching parts of central MN and eastern ND by Monday evening. Storm development/evolution across the region remains unclear, with the stronger large-scale ascent expected to remain north of the international border. However, strong to locally extreme instability is expected to develop along/east of the surface trough across the Dakotas, and along and to the south/west of the northward moving warm front. While the warm sector may remain capped for much of the day, at least isolated storm development will be possible near the warm front, and also potentially near the surface trough/cold front. Elevated convection may also develop to the cool side of the warm front, especially during the evening when some intensification of a southwesterly low-level jet is expected. Deep-layer shear will be sufficient for organized convection. Any surface-based supercell development could pose a conditional risk of all severe hazards, including some potential for significant hail and/or wind given the very favorable thermodynamic environment. Depending on the evolution of initial storm development, an MCS could develop and move southeastward along the instability gradient, though this scenario remains rather uncertain at this time. ...Coastal Carolinas... Some guidance suggests a southeastward-moving cold front will slow down or stall across eastern NC/SC, resulting in the potential for scattered thunderstorm development during the afternoon, within a moderately unstable environment. Should this occur, modest northwesterly flow aloft could support sufficient storm organization for an isolated damaging wind and hail threat. This scenario remains uncertain, but severe probabilities may eventually be needed if confidence increases. ..Dean.. 06/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sat Jun 22 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF MN...NORTHWEST WI...WESTERN UPPER MI... ...SUMMARY... Severe thunderstorms are possible on Monday across parts of the northern Great Plains into the upper Mississippi Valley and Great Lakes. ...Northern Great Plains into the upper MS Valley/Great Lakes... Uncertainty remains rather high regarding storm potential on Monday from the northern Great Plains into the upper MS Valley and Great Lakes. However, with some conditional significant-severe potential within a favorable environment, a Slight Risk has been added for parts of MN into northwest WI and western upper MI, where confidence is currently highest in isolated to widely scattered storm coverage. A mid/upper-level shortwave trough and related surface low are forecast to move eastward across parts of SK/MB on Monday. A secondary surface low is forecast to develop along a trailing surface trough/weak cold front across the Dakotas. A surface boundary initially draped roughly from the Ohio Valley northwestward through parts of IA and southeast SD is forecast to move northward as a warm front, potentially reaching parts of central MN and eastern ND by Monday evening. Storm development/evolution across the region remains unclear, with the stronger large-scale ascent expected to remain north of the international border. However, strong to locally extreme instability is expected to develop along/east of the surface trough across the Dakotas, and along and to the south/west of the northward moving warm front. While the warm sector may remain capped for much of the day, at least isolated storm development will be possible near the warm front, and also potentially near the surface trough/cold front. Elevated convection may also develop to the cool side of the warm front, especially during the evening when some intensification of a southwesterly low-level jet is expected. Deep-layer shear will be sufficient for organized convection. Any surface-based supercell development could pose a conditional risk of all severe hazards, including some potential for significant hail and/or wind given the very favorable thermodynamic environment. Depending on the evolution of initial storm development, an MCS could develop and move southeastward along the instability gradient, though this scenario remains rather uncertain at this time. ...Coastal Carolinas... Some guidance suggests a southeastward-moving cold front will slow down or stall across eastern NC/SC, resulting in the potential for scattered thunderstorm development during the afternoon, within a moderately unstable environment. Should this occur, modest northwesterly flow aloft could support sufficient storm organization for an isolated damaging wind and hail threat. This scenario remains uncertain, but severe probabilities may eventually be needed if confidence increases. ..Dean.. 06/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sat Jun 22 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF MN...NORTHWEST WI...WESTERN UPPER MI... ...SUMMARY... Severe thunderstorms are possible on Monday across parts of the northern Great Plains into the upper Mississippi Valley and Great Lakes. ...Northern Great Plains into the upper MS Valley/Great Lakes... Uncertainty remains rather high regarding storm potential on Monday from the northern Great Plains into the upper MS Valley and Great Lakes. However, with some conditional significant-severe potential within a favorable environment, a Slight Risk has been added for parts of MN into northwest WI and western upper MI, where confidence is currently highest in isolated to widely scattered storm coverage. A mid/upper-level shortwave trough and related surface low are forecast to move eastward across parts of SK/MB on Monday. A secondary surface low is forecast to develop along a trailing surface trough/weak cold front across the Dakotas. A surface boundary initially draped roughly from the Ohio Valley northwestward through parts of IA and southeast SD is forecast to move northward as a warm front, potentially reaching parts of central MN and eastern ND by Monday evening. Storm development/evolution across the region remains unclear, with the stronger large-scale ascent expected to remain north of the international border. However, strong to locally extreme instability is expected to develop along/east of the surface trough across the Dakotas, and along and to the south/west of the northward moving warm front. While the warm sector may remain capped for much of the day, at least isolated storm development will be possible near the warm front, and also potentially near the surface trough/cold front. Elevated convection may also develop to the cool side of the warm front, especially during the evening when some intensification of a southwesterly low-level jet is expected. Deep-layer shear will be sufficient for organized convection. Any surface-based supercell development could pose a conditional risk of all severe hazards, including some potential for significant hail and/or wind given the very favorable thermodynamic environment. Depending on the evolution of initial storm development, an MCS could develop and move southeastward along the instability gradient, though this scenario remains rather uncertain at this time. ...Coastal Carolinas... Some guidance suggests a southeastward-moving cold front will slow down or stall across eastern NC/SC, resulting in the potential for scattered thunderstorm development during the afternoon, within a moderately unstable environment. Should this occur, modest northwesterly flow aloft could support sufficient storm organization for an isolated damaging wind and hail threat. This scenario remains uncertain, but severe probabilities may eventually be needed if confidence increases. ..Dean.. 06/22/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...Synopsis... An upper-level trough will move through Washington during the afternoon. A strong pressure gradient will develop as a surface low deepens in the northern Rockies into Alberta/Saskatchewan. ...Northwest... Strong westerly surface winds across the Cascades will promote downslope drying into the Columbia Basin during the afternoon. Given some push of marine air to the east, it is possible that RH will not become overly low. However, generally dry fuels and 15-20 mph winds will support an elevated fire weather risk. ...OR/CA/NV... The surface pressure gradient and mid-level winds will be weaker than farther north, but confidence in RH of 10-20% is much higher. Winds could locally approach 20 mph, but will more broadly be around 15 mph. Locally elevated conditions are expected to the lee of the southern Cascades and northern Sierra. ...Snake River Plain... On the fringe of the strong mid-level winds, favorably oriented with the Valley, winds of 15-25 mph appear possible. RH of 15-20% can be expected during the afternoon. Though meteorological conditions could become critical, fuels are not sufficiently dry to support more than an elevated risk. ..Wendt.. 06/22/2024 ...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 0101 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...Synopsis... An upper-level trough will move through Washington during the afternoon. A strong pressure gradient will develop as a surface low deepens in the northern Rockies into Alberta/Saskatchewan. ...Northwest... Strong westerly surface winds across the Cascades will promote downslope drying into the Columbia Basin during the afternoon. Given some push of marine air to the east, it is possible that RH will not become overly low. However, generally dry fuels and 15-20 mph winds will support an elevated fire weather risk. ...OR/CA/NV... The surface pressure gradient and mid-level winds will be weaker than farther north, but confidence in RH of 10-20% is much higher. Winds could locally approach 20 mph, but will more broadly be around 15 mph. Locally elevated conditions are expected to the lee of the southern Cascades and northern Sierra. ...Snake River Plain... On the fringe of the strong mid-level winds, favorably oriented with the Valley, winds of 15-25 mph appear possible. RH of 15-20% can be expected during the afternoon. Though meteorological conditions could become critical, fuels are not sufficiently dry to support more than an elevated risk. ..Wendt.. 06/22/2024 ...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 0101 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...Synopsis... An upper-level trough will move through Washington during the afternoon. A strong pressure gradient will develop as a surface low deepens in the northern Rockies into Alberta/Saskatchewan. ...Northwest... Strong westerly surface winds across the Cascades will promote downslope drying into the Columbia Basin during the afternoon. Given some push of marine air to the east, it is possible that RH will not become overly low. However, generally dry fuels and 15-20 mph winds will support an elevated fire weather risk. ...OR/CA/NV... The surface pressure gradient and mid-level winds will be weaker than farther north, but confidence in RH of 10-20% is much higher. Winds could locally approach 20 mph, but will more broadly be around 15 mph. Locally elevated conditions are expected to the lee of the southern Cascades and northern Sierra. ...Snake River Plain... On the fringe of the strong mid-level winds, favorably oriented with the Valley, winds of 15-25 mph appear possible. RH of 15-20% can be expected during the afternoon. Though meteorological conditions could become critical, fuels are not sufficiently dry to support more than an elevated risk. ..Wendt.. 06/22/2024 ...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 0100 AM CDT Sat Jun 22 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A flattened upper-level ridge will be situated across much of the southern CONUS today. With time, shortwave ridging will build over parts of the Great Basin into the Rockies. Stronger, zonal mid-level winds will exist within the northern portions of the CONUS. Late in the period, an upper-level trough will approach the Northwest. Dry and modestly breezy conditions are possible within parts of the Great Basin into a few areas east of the Cascades in the Northwest. Given weak large-scale features, winds will generally remain too light for more than locally elevated concerns. Cloud cover in the Northwest will also keep RH values somewhat marginal and any increase in winds will tend to be after peak heating. ..Wendt.. 06/22/2024 ...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 0100 AM CDT Sat Jun 22 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A flattened upper-level ridge will be situated across much of the southern CONUS today. With time, shortwave ridging will build over parts of the Great Basin into the Rockies. Stronger, zonal mid-level winds will exist within the northern portions of the CONUS. Late in the period, an upper-level trough will approach the Northwest. Dry and modestly breezy conditions are possible within parts of the Great Basin into a few areas east of the Cascades in the Northwest. Given weak large-scale features, winds will generally remain too light for more than locally elevated concerns. Cloud cover in the Northwest will also keep RH values somewhat marginal and any increase in winds will tend to be after peak heating. ..Wendt.. 06/22/2024 ...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 0100 AM CDT Sat Jun 22 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A flattened upper-level ridge will be situated across much of the southern CONUS today. With time, shortwave ridging will build over parts of the Great Basin into the Rockies. Stronger, zonal mid-level winds will exist within the northern portions of the CONUS. Late in the period, an upper-level trough will approach the Northwest. Dry and modestly breezy conditions are possible within parts of the Great Basin into a few areas east of the Cascades in the Northwest. Given weak large-scale features, winds will generally remain too light for more than locally elevated concerns. Cloud cover in the Northwest will also keep RH values somewhat marginal and any increase in winds will tend to be after peak heating. ..Wendt.. 06/22/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA/NY INTO VT/NH...WESTERN MA...NORTHWEST CT...EXTREME WESTERN ME... ...SUMMARY... Scattered damaging winds and a few tornadoes are possible across parts of the Northeast on Sunday. ...Northeast... A Slight Risk has been added for parts of the Northeast on Sunday, with potential for scattered damaging winds and a few tornadoes during the afternoon and early evening. Guidance still varies regarding the amplitude of embedded shortwaves moving through a large-scale upper trough from the Great Lakes into the Northeast on Sunday, which in turn results in uncertainty regarding the strength/track of a related surface low. In general, potential for rather strong low/midlevel flow to overspread a moderately unstable environment remains evident across much of the Northeast. Scattered thunderstorm development will be possible by afternoon, both along and in advance of the cold front. Organized cells/clusters will be possible, including the potential for a few supercells. A zone of relatively backed surface winds may persist through the day from central/eastern NY into parts of NH/VT/western MA, in closer proximity to the surface warm front. Locally enhanced low-level shear/SRH and sufficient deep-layer shear will support some potential for tornadic supercells across this area. Otherwise, scattered damaging winds will be possible with both frontal and prefrontal convection across the broader region during the afternoon and evening, before an expected weakening trend by later Sunday night. ...OH/TN Valley vicinity... The cold front trailing from the New England system will move across parts of the Ohio Valley during the afternoon and evening. Thunderstorm development will be possible along/ahead of the front, within a moderately unstable and modestly sheared environment. A few stronger cells or small clusters will be possible within this regime, with a threat of locally damaging wind. Some convection may spread into parts of northern MS/AL Sunday night, though the potential severity of any nocturnal convection in this area remains uncertain. ...Eastern MT into northwest ND... A shortwave trough is forecast to move east-northeastward from the Pacific Northwest into parts of BC/AB by Sunday evening. A deepening surface cyclone will accompany this shortwave, with a cold front trailing southward into parts of MT. Low-level southeasterly flow will transport modest low-level moisture into parts of eastern MT, resulting in the potential for moderate destabilization. Deep-layer shear will be favorable for organized convection, but large-scale ascent attendant to the shortwave trough may tend to remain north of the international border. Development of a strong/severe storm or two across eastern MT cannot be ruled out by early evening, which would then potentially spread into northwest ND Sunday night. A Marginal Risk has been added for this conditional scenario. ..Dean.. 06/22/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA/NY INTO VT/NH...WESTERN MA...NORTHWEST CT...EXTREME WESTERN ME... ...SUMMARY... Scattered damaging winds and a few tornadoes are possible across parts of the Northeast on Sunday. ...Northeast... A Slight Risk has been added for parts of the Northeast on Sunday, with potential for scattered damaging winds and a few tornadoes during the afternoon and early evening. Guidance still varies regarding the amplitude of embedded shortwaves moving through a large-scale upper trough from the Great Lakes into the Northeast on Sunday, which in turn results in uncertainty regarding the strength/track of a related surface low. In general, potential for rather strong low/midlevel flow to overspread a moderately unstable environment remains evident across much of the Northeast. Scattered thunderstorm development will be possible by afternoon, both along and in advance of the cold front. Organized cells/clusters will be possible, including the potential for a few supercells. A zone of relatively backed surface winds may persist through the day from central/eastern NY into parts of NH/VT/western MA, in closer proximity to the surface warm front. Locally enhanced low-level shear/SRH and sufficient deep-layer shear will support some potential for tornadic supercells across this area. Otherwise, scattered damaging winds will be possible with both frontal and prefrontal convection across the broader region during the afternoon and evening, before an expected weakening trend by later Sunday night. ...OH/TN Valley vicinity... The cold front trailing from the New England system will move across parts of the Ohio Valley during the afternoon and evening. Thunderstorm development will be possible along/ahead of the front, within a moderately unstable and modestly sheared environment. A few stronger cells or small clusters will be possible within this regime, with a threat of locally damaging wind. Some convection may spread into parts of northern MS/AL Sunday night, though the potential severity of any nocturnal convection in this area remains uncertain. ...Eastern MT into northwest ND... A shortwave trough is forecast to move east-northeastward from the Pacific Northwest into parts of BC/AB by Sunday evening. A deepening surface cyclone will accompany this shortwave, with a cold front trailing southward into parts of MT. Low-level southeasterly flow will transport modest low-level moisture into parts of eastern MT, resulting in the potential for moderate destabilization. Deep-layer shear will be favorable for organized convection, but large-scale ascent attendant to the shortwave trough may tend to remain north of the international border. Development of a strong/severe storm or two across eastern MT cannot be ruled out by early evening, which would then potentially spread into northwest ND Sunday night. A Marginal Risk has been added for this conditional scenario. ..Dean.. 06/22/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Jun 22 2024 Valid 231200Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA/NY INTO VT/NH...WESTERN MA...NORTHWEST CT...EXTREME WESTERN ME... ...SUMMARY... Scattered damaging winds and a few tornadoes are possible across parts of the Northeast on Sunday. ...Northeast... A Slight Risk has been added for parts of the Northeast on Sunday, with potential for scattered damaging winds and a few tornadoes during the afternoon and early evening. Guidance still varies regarding the amplitude of embedded shortwaves moving through a large-scale upper trough from the Great Lakes into the Northeast on Sunday, which in turn results in uncertainty regarding the strength/track of a related surface low. In general, potential for rather strong low/midlevel flow to overspread a moderately unstable environment remains evident across much of the Northeast. Scattered thunderstorm development will be possible by afternoon, both along and in advance of the cold front. Organized cells/clusters will be possible, including the potential for a few supercells. A zone of relatively backed surface winds may persist through the day from central/eastern NY into parts of NH/VT/western MA, in closer proximity to the surface warm front. Locally enhanced low-level shear/SRH and sufficient deep-layer shear will support some potential for tornadic supercells across this area. Otherwise, scattered damaging winds will be possible with both frontal and prefrontal convection across the broader region during the afternoon and evening, before an expected weakening trend by later Sunday night. ...OH/TN Valley vicinity... The cold front trailing from the New England system will move across parts of the Ohio Valley during the afternoon and evening. Thunderstorm development will be possible along/ahead of the front, within a moderately unstable and modestly sheared environment. A few stronger cells or small clusters will be possible within this regime, with a threat of locally damaging wind. Some convection may spread into parts of northern MS/AL Sunday night, though the potential severity of any nocturnal convection in this area remains uncertain. ...Eastern MT into northwest ND... A shortwave trough is forecast to move east-northeastward from the Pacific Northwest into parts of BC/AB by Sunday evening. A deepening surface cyclone will accompany this shortwave, with a cold front trailing southward into parts of MT. Low-level southeasterly flow will transport modest low-level moisture into parts of eastern MT, resulting in the potential for moderate destabilization. Deep-layer shear will be favorable for organized convection, but large-scale ascent attendant to the shortwave trough may tend to remain north of the international border. Development of a strong/severe storm or two across eastern MT cannot be ruled out by early evening, which would then potentially spread into northwest ND Sunday night. A Marginal Risk has been added for this conditional scenario. ..Dean.. 06/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sat Jun 22 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN IOWA...NORTHERN MISSOURI...SOUTHERN WISCONSIN...NORTHERN ILLINOIS...CENTRAL AND SOUTHWESTERN LOWER MICHIGAN... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening across parts of the Midwest and Great Lakes region. One or two clusters of storms may evolve and pose a risk for damaging wind gusts, but a couple of supercells posing a risk for tornadoes are possible as well. ...Synopsis... Models indicate that persistent mid/upper ridging will become increasingly suppressed across and east-southeast of the Upper Midwest later today through tonight. As flow trends broadly cyclonic across the Great Lakes and Ohio Valley into the Northeast and Mid Atlantic, the slowly weakening center of this ridging is forecast to shift from the Mid South into the southern Great Plains by 12Z Sunday. It appears that one notable, but relatively low-amplitude, short wave perturbation emerging from the Great Basin will accelerate east-northeastward, then eastward, across the Upper Midwest through the Great Lakes during this period, as a somewhat stronger upstream perturbation digs east-southeast of the Canadian Prairies toward the upper Great Lakes region. Although there is substantive spread among the various model output concerning the evolution, the lead impulse is forecast to support modest cyclogenesis along a surface front, generally across or east-northeast of Iowa through the lower Michigan vicinity by late tonight. As this occurs, a trailing cold front likely will advance southward through portions of the central Great Plains, lower Missouri and Ohio Valleys. The modifying western flank of a preceding intrusion of cooler air may be slow to shift northeast of the southern New England and Adirondacks vicinity, while a reinforcing intrusion of cool air begins to advance south of the international border into the northern U.S. Great Plains by this evening. Destabilization along and just south of all of these boundaries may provide a focus for strong to severe thunderstorm development this afternoon and evening. ...Great Lakes into lower Missouri Valley vicinity... Severe weather potential remains somewhat unclear for this period due to the model discrepancies concerning the surface cyclone evolution, and the stabilizing influence of potentially considerable lingering early period convective development across the Midwest into Great Lakes region. However, a belt of 30-50+ kt southwesterly to westerly flow in the 850-500 mb layer may overspread a destabilizing environment along and south of a left-over outflow boundary across parts of eastern Iowa through southern Wisconsin/northern Illinois, and the stalled frontal zone over central lower Michigan during the day. Seasonably high boundary-layer moisture content (including dew points near 70F) will become supportive of at least weak to moderate CAPE, in the presence of moderate to strong shear, including sizable clockwise-curved low-level hodographs. This environment may become supportive of a few supercell structures accompanied by a risk for tornadoes, before increasing thunderstorm development ahead of the southeastward advancing cold front poses primarily a risk for damaging surface gusts into this evening. ...Northern Mid Atlantic... Deep-layer wind fields and shear are likely to remain weak, but moderately large CAPE (in excess of 2000 J/kg) may once again develop within weak surface troughing, along and southwest of the remnant surface frontal zone. It appears that this will become supportive of scattered strong thunderstorms with potential to produce damaging wind gusts, as mid-level heights begin to slowly fall late this afternoon into this evening. ...Northern Great Plains... Stronger mid/upper forcing for ascent and mid-level cooling are likely to remain north of the international border beyond peak daytime heating, but an isolated strong storm or two may advect south of the international border by this evening, accompanied by a risk for marginally severe hail and wind. ..Kerr/Wendt.. 06/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sat Jun 22 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN IOWA...NORTHERN MISSOURI...SOUTHERN WISCONSIN...NORTHERN ILLINOIS...CENTRAL AND SOUTHWESTERN LOWER MICHIGAN... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening across parts of the Midwest and Great Lakes region. One or two clusters of storms may evolve and pose a risk for damaging wind gusts, but a couple of supercells posing a risk for tornadoes are possible as well. ...Synopsis... Models indicate that persistent mid/upper ridging will become increasingly suppressed across and east-southeast of the Upper Midwest later today through tonight. As flow trends broadly cyclonic across the Great Lakes and Ohio Valley into the Northeast and Mid Atlantic, the slowly weakening center of this ridging is forecast to shift from the Mid South into the southern Great Plains by 12Z Sunday. It appears that one notable, but relatively low-amplitude, short wave perturbation emerging from the Great Basin will accelerate east-northeastward, then eastward, across the Upper Midwest through the Great Lakes during this period, as a somewhat stronger upstream perturbation digs east-southeast of the Canadian Prairies toward the upper Great Lakes region. Although there is substantive spread among the various model output concerning the evolution, the lead impulse is forecast to support modest cyclogenesis along a surface front, generally across or east-northeast of Iowa through the lower Michigan vicinity by late tonight. As this occurs, a trailing cold front likely will advance southward through portions of the central Great Plains, lower Missouri and Ohio Valleys. The modifying western flank of a preceding intrusion of cooler air may be slow to shift northeast of the southern New England and Adirondacks vicinity, while a reinforcing intrusion of cool air begins to advance south of the international border into the northern U.S. Great Plains by this evening. Destabilization along and just south of all of these boundaries may provide a focus for strong to severe thunderstorm development this afternoon and evening. ...Great Lakes into lower Missouri Valley vicinity... Severe weather potential remains somewhat unclear for this period due to the model discrepancies concerning the surface cyclone evolution, and the stabilizing influence of potentially considerable lingering early period convective development across the Midwest into Great Lakes region. However, a belt of 30-50+ kt southwesterly to westerly flow in the 850-500 mb layer may overspread a destabilizing environment along and south of a left-over outflow boundary across parts of eastern Iowa through southern Wisconsin/northern Illinois, and the stalled frontal zone over central lower Michigan during the day. Seasonably high boundary-layer moisture content (including dew points near 70F) will become supportive of at least weak to moderate CAPE, in the presence of moderate to strong shear, including sizable clockwise-curved low-level hodographs. This environment may become supportive of a few supercell structures accompanied by a risk for tornadoes, before increasing thunderstorm development ahead of the southeastward advancing cold front poses primarily a risk for damaging surface gusts into this evening. ...Northern Mid Atlantic... Deep-layer wind fields and shear are likely to remain weak, but moderately large CAPE (in excess of 2000 J/kg) may once again develop within weak surface troughing, along and southwest of the remnant surface frontal zone. It appears that this will become supportive of scattered strong thunderstorms with potential to produce damaging wind gusts, as mid-level heights begin to slowly fall late this afternoon into this evening. ...Northern Great Plains... Stronger mid/upper forcing for ascent and mid-level cooling are likely to remain north of the international border beyond peak daytime heating, but an isolated strong storm or two may advect south of the international border by this evening, accompanied by a risk for marginally severe hail and wind. ..Kerr/Wendt.. 06/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sat Jun 22 2024 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF CENTRAL AND EASTERN IOWA...NORTHERN MISSOURI...SOUTHERN WISCONSIN...NORTHERN ILLINOIS...CENTRAL AND SOUTHWESTERN LOWER MICHIGAN... ...SUMMARY... Severe thunderstorms are possible this afternoon and evening across parts of the Midwest and Great Lakes region. One or two clusters of storms may evolve and pose a risk for damaging wind gusts, but a couple of supercells posing a risk for tornadoes are possible as well. ...Synopsis... Models indicate that persistent mid/upper ridging will become increasingly suppressed across and east-southeast of the Upper Midwest later today through tonight. As flow trends broadly cyclonic across the Great Lakes and Ohio Valley into the Northeast and Mid Atlantic, the slowly weakening center of this ridging is forecast to shift from the Mid South into the southern Great Plains by 12Z Sunday. It appears that one notable, but relatively low-amplitude, short wave perturbation emerging from the Great Basin will accelerate east-northeastward, then eastward, across the Upper Midwest through the Great Lakes during this period, as a somewhat stronger upstream perturbation digs east-southeast of the Canadian Prairies toward the upper Great Lakes region. Although there is substantive spread among the various model output concerning the evolution, the lead impulse is forecast to support modest cyclogenesis along a surface front, generally across or east-northeast of Iowa through the lower Michigan vicinity by late tonight. As this occurs, a trailing cold front likely will advance southward through portions of the central Great Plains, lower Missouri and Ohio Valleys. The modifying western flank of a preceding intrusion of cooler air may be slow to shift northeast of the southern New England and Adirondacks vicinity, while a reinforcing intrusion of cool air begins to advance south of the international border into the northern U.S. Great Plains by this evening. Destabilization along and just south of all of these boundaries may provide a focus for strong to severe thunderstorm development this afternoon and evening. ...Great Lakes into lower Missouri Valley vicinity... Severe weather potential remains somewhat unclear for this period due to the model discrepancies concerning the surface cyclone evolution, and the stabilizing influence of potentially considerable lingering early period convective development across the Midwest into Great Lakes region. However, a belt of 30-50+ kt southwesterly to westerly flow in the 850-500 mb layer may overspread a destabilizing environment along and south of a left-over outflow boundary across parts of eastern Iowa through southern Wisconsin/northern Illinois, and the stalled frontal zone over central lower Michigan during the day. Seasonably high boundary-layer moisture content (including dew points near 70F) will become supportive of at least weak to moderate CAPE, in the presence of moderate to strong shear, including sizable clockwise-curved low-level hodographs. This environment may become supportive of a few supercell structures accompanied by a risk for tornadoes, before increasing thunderstorm development ahead of the southeastward advancing cold front poses primarily a risk for damaging surface gusts into this evening. ...Northern Mid Atlantic... Deep-layer wind fields and shear are likely to remain weak, but moderately large CAPE (in excess of 2000 J/kg) may once again develop within weak surface troughing, along and southwest of the remnant surface frontal zone. It appears that this will become supportive of scattered strong thunderstorms with potential to produce damaging wind gusts, as mid-level heights begin to slowly fall late this afternoon into this evening. ...Northern Great Plains... Stronger mid/upper forcing for ascent and mid-level cooling are likely to remain north of the international border beyond peak daytime heating, but an isolated strong storm or two may advect south of the international border by this evening, accompanied by a risk for marginally severe hail and wind. ..Kerr/Wendt.. 06/22/2024 Read more