Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0144 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...Synopsis... Isolated to scattered dry thunderstorms will continue to be the primary fire weather concern across the country for today. Latest GOES PWAT imagery and recent 00 UTC soundings both show a gradual increase in moisture content across the Great Basin and central Rockies. This increase in moisture will modulate the potential for purely dry thunderstorms this afternoon, with a mix of wet/dry convection becoming more likely. Regardless, MRMS rainfall estimates show several dry thunderstorms ongoing as of 06 UTC across parts of ID and WY. With only a gradual moistening trend expected and receptive fuels still in place for most locations (mainly anywhere away from swaths of heavy rainfall over the past 2 days), dry lightning, as well as gusty outflow winds, will continue to be a fire weather threat. ..Moore.. 07/15/2024 ...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 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Jul 15 2024 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...AND FROM THE UPPER OH VALLEY INTO WESTERN NY... ...SUMMARY... Strong to severe thunderstorms are possible from the central Plains across the Mid Mississippi and Ohio Valleys into the Northeast on Tuesday. Greater severe-thunderstorm potential is anticipated across the central High Plains and from the Upper Ohio Valley into western New York. ...Synopsis... Western CONUS upper ridging is expected to build on Tuesday, reaching into much of western Canada by early Wednesday morning. Upper troughing is anticipated downstream across eastern Canada and the northeast CONUS, anchored by a cyclone initially over far northwest Ontario. This cyclone and associated troughing are expected to progress eastward throughout the day, maintaining a belt of moderate cyclonic flow aloft from the Upper Midwest across the Upper Great Lakes, and into the Northeast. Surface low associated with the Canadian cyclone will likely be over eastern Ontario and southwest Quebec early Tuesday morning, with a cold front extended southwestward from the low to another low in central KS. A moist airmass will be in place ahead of this front, with dewpoints ranging from the mid/upper 60s across KS increasing into the low 70s across the OH Valley and then decreasing again into the upper 60s across the Northeast. Thunderstorm development is probable along the length of this front as it continues southward/southeastward and the airmass diurnally destabilizes. Thunderstorm development is also anticipated across the central Rockies with progression into the central High Plains and central Plains possible during the afternoon and evening. ...Central High Plains into the Central Plains... Expectation is for thunderstorms to develop across the high terrain of the central Rockies, within the westerly/northwesterly flow aloft along the northern periphery of the Southwest ridge. Post-frontal upslope flow is anticipated across the central High Plains, bringing upper 50s/low 60s dewpoints into the Colorado Plains and supporting moderate buoyancy. This may help support the development of strong to severe storms as thunderstorms move off the higher terrain and into this moderately buoyant airmass downstream. Moderate vertical shear could help support greater updraft persistence and the potential for organization into a more organized linear system, with maintenance into western and central KS possible. Damaging gusts are the primary severe risk, but some isolated hail is possible as well. Additional thunderstorm development appears possible Tuesday afternoon in the north-central NE vicinity, near a secondary surface low expected to drift southeastward from southwest SD into north-central NE. Moderate buoyancy and vertical shear (supported by deep northwesterly flow aloft) could help support cold-pool organization with the resulting convective line progress southeastward across NE and potentially into northern KS. ...North-Central OK through Lower MO and OH Valleys into the Northeast... Scattered to numerous thunderstorms are expected along the length of the front Tuesday afternoon and evening. Much of the stronger mid-level flow will be displaced north of the front and better low-level moisture. However, despite relatively modest vertical shear, strong buoyancy could still support robust updrafts and the potential for precipitation loading and damaging gusts along the length of the front. Some overlap between the stronger mid-level flow and better buoyancy is possible from the Upper OH Valley into western NY. Shear vector should be more orthogonal to the front across this region as well. As a result, there appears to be a greater potential for strong to severe storms here than areas farther west, where generally weaker flow aloft and more front-parallel vertical shear will limit storm organization. ..Mosier.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 15 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN IOWA INTO NORTHERN ILLINOIS AND FAR NORTHWEST INDIANA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS...MUCH OF THE MIDWEST...AND PARTS OF NEW YORK AND PENNSYLVANIA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across portions of the Midwest, central High Plains, and the lower Great Lakes. The greatest potential for severe/damaging winds appears to be across eastern Iowa into Illinois and Indiana. More isolated strong to severe thunderstorms are possible across southeast Arizona and the New England region. ...Synopsis... A complex severe-weather setup is anticipated for today across the Midwest with the potential for one or more severe MCSs. The details of how the severe threat will evolve this afternoon/evening will be conditional on convective evolution of ongoing MCSs across ND and IL/IN through 12 UTC, which introduces considerable uncertainty into the forecast. In general, a broad surface cyclone is forecast to deepen slightly over the upper Great Lakes over the next 12-24 hours as a low-amplitude mid-level wave traverses the northern CONUS. As this occurs, a weak cold front (noted in surface obs across MT and the western Dakotas as of 05 UTC) will migrate south into the Midwest and central Plains by late afternoon. Thunderstorm development and/or re-intensification is anticipated along this boundary and on the northern periphery of a reservoir of a high theta-e air mass in place over the central Plains. ...Midwest... Recent CAM guidance depicts a range of possible scenarios for the next 24 hour period. The most probable scenario involves the cluster of thunderstorms ongoing across the Dakotas as of 05 UTC, which will likely weaken by 12 UTC as it approaches the mid-MS River Valley. The remnants of this complex may act as foci for re-development by mid to late afternoon on the northeastern periphery of a reservoir of high theta-e air (denoted by dewpoints in the low to mid 70s) across IA, southern WI, and northern IL. Thunderstorms emerging from this zone will likely organize and intensify into an organized MCS as it propagates southeast into eastern IA and northern IL. If the ND cluster weakens substantially by late morning, convective initiation will likely be focused along the cold front as it migrates south and/or along a residual outflow boundary from ongoing storms. The location of initiation varies in latest model solutions, which introduces uncertainty on where the corridors of relatively higher severe-wind potential will be established. Higher wind probabilities were placed based on where ensemble guidance shows the best QPF signal, which likely correlates to where deep convection will most likely occur. Additionally, forecast soundings suggest sufficient low-level SRH may be in place to support a tornado threat across eastern IA into northern IL; however, this threat will likely be conditional on realizing a predominantly discrete storm mode prior to upscale growth and/or embedded circulations with an organized MCS. ...Northeast... 05 UTC regional radar imagery reveals a mature MCS ongoing across northern IL/IN. A vorticity maximum associated with this system is apparent over lower Lake Michigan, and is expected to migrate east, reaching the lower Great Lakes by around 18 UTC. Mid-level lapse rates are fairly modest across New England per 00 UTC soundings, but dewpoints in the upper 60s/lower 70s should support around 500-1000 J/kg MLCAPE by peak heating. Thunderstorm development ahead of the MCV appears likely based on latest CAM guidance, and slightly augmented flow in the vicinity of the vorticity maximum should result in around 25-30 knots of effective bulk shear. These environmental conditions will likely be sufficient to support organized convective clusters within a somewhat focused corridor across parts of PA and NY. ...Central High Plains... Steep mid-level lapse rates and mid-level moisture across the central Rockies will foster another day of widely scattered thunderstorms across CO and WY. Storms will migrate into the central High Plains by late afternoon amid a mean easterly flow regime. Weak low-level storm-relative winds and a deeply mixed boundary layer should yield outflow-dominant storms, but stronger mid-level flow compared to previous days may favor some thunderstorm clustering/cold pool amalgamation. Consequently, a more focused corridor of severe-wind potential may emerge across the central High Plains. While the exact location of where such clusters may emerge remains uncertain, ensemble guidance suggests this is most probable across the NE Panhandle into northeast CO/northwest KS. ...Southeast Arizona... Thunderstorm development is expected again along the eastern portions of the Mongollon Rim and out of the Gila region of southwest NM. Southwesterly flow out of Gulf of California will maintain dewpoints in the upper 50s to low 60s that should support MLCAPE values above 1000 J/kg. Warm temperatures in the upper 90s to low 100s should support another day of 40-50 F dewpoint depressions amid deep boundary-layer mixing. Storms moving off the terrain will be capable of strong to severe downburst winds as they migrate into the buoyant, but deeply mixed environment at lower elevations. ..Moore/Darrow.. 07/15/2024 Read more