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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jul 14 2024 Valid 142000Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE NORTHERN PLAINS AND THE MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... Strong to severe thunderstorms are still expected from the northern Plains into the Upper Midwest and Ohio Valley this afternoon through tonight. ...20Z Update... The primary changes made to this outlook were to adjust severe probabilities in the northern Plains to account for both the latest guidance consensus, and reflect recent trends in observations and re-analysis. Visible satellite and surface observations indicate a northwest-to-southeast oriented baroclinic boundary draped over extreme northeast MT/northwestern ND, down to central and eastern SD, extending to the MN border. Though MLCINH remains over the warm sector, and additional airmass modification is needed for appreciable airmass recovery after earlier storms, several hours of surface heating remain. Furthermore, this boundary may serve as a focal point for deep-moist convection to initiate and anchor on later this evening. Latest guidance consensus suggests that supercell structures with mainly a hail threat will materialize closer to the U.S./Canada by around 00Z (perhaps before). Thereafter, upscale growth into an MCS is possible along the baroclinic boundary. Should this occur, steep mid-level lapse rates, along with adequate vertical wind shear may promote a corridor of severe gusts, and a 75+ mph gust or two is possible, hence the addition of a hatched area within the Northern Plains Category 2/Slight Risk. The Slight Risk in the Midwest was also expanded a bit westward in IA to account for potential westward convective initiation. This convection may also form into an MCS and traverse the same areas impacted by an earlier MCS, hence why changes were not made farther east despite some convective overturning noted. Otherwise, the forecast remains on track across the west of the CONUS. ..Squitieri.. 07/14/2024 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jul 14 2024/ ...Synopsis... West-northwesterly flow aloft is in place today across the northern Plains and Midwest, with several small-scale features noted in satellite imagery embedded in the flow. This will result in multiple MCSs from MT into the upper OH valley during this period. ...IN/OH this afternoon... A linear MCS is currently ongoing over portions of northwest IN and northeast IL. Strong heating ahead of the system across much of IN/OH, combined with surface dewpoints near 70F will yield a corridor of moderate CAPE, likely aiding intensification of storms. Given 20-25 knots of mid-level flow and relatively steep mid-level lapse rates, a few strong to severe storms are possible through the afternoon. Please refer to MCD #1612 for further details. ...Eastern IA/Southern WI/Northern IL/Northern IN... Strong heating is occurring in wake of aforementioned MCS across parts of eastern IA/southern WI/northern IL, where ample low-level moisture remains. A well-defined remnant MCV from the overnight severe MCS over SD is currently over northern IA, and will track into the destabilizing air mass. A consensus of morning CAM solutions suggest that thunderstorms will develop ahead of the MCV and track toward northern IL/IN this evening. Damaging winds and some hail would be the main threats. ...Northeast MT/Dakotas/Western MN... Water vapor imagery shows a strong upper trough digging southeastward across southern AB. Large scale lift ahead of this system will lead to scattered thunderstorm development by early evening across portions of northeast MT and western ND. Model solutions remain diverse in the details of how this convective scenario unfolds. However, it appears likely that one or more clusters of strong/severe storms will track across ND and into northeast SD/western MN during the night. Large hail and damaging winds will be possible with these storms. ...Mid Atlantic... Widely scattered afternoon thunderstorms are expected today from parts of eastern VA northeastward into eastern PA and NJ. Winds through the low/mid troposphere are rather weak and lapse rates are poor. Nevertheless, ample low-level moisture and rather high PWAT values may result in gusty winds near the strongest storms. ...AZ... Clear skies early today combined with dewpoints in the mid 60s will yield a hot and moderately unstable air mass this afternoon with MLCAPE values of 1000-1500 J/kg. Thunderstorms are expected to form over the higher terrain of western NM/eastern AZ and along the rim later today, with sufficient easterly mid-level flow to aid propagation off the mountains. Locally damaging wind gusts may accompany these storms. Read more

WW 0532 Status Updates
STATUS REPORT ON WW 532 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 SE IND TO 25 N LUK TO 25 ESE DAY TO 30 WNW MFD. ..LYONS..07/14/24 ATTN...WFO...IWX...IND...ILN...CLE... STATUS REPORT FOR WS 532 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OHC027-033-041-045-047-049-057-073-083-089-097-101-117-129-141- 159-165-142140- OH . OHIO COUNTIES INCLUDED ARE CLINTON CRAWFORD DELAWARE FAIRFIELD FAYETTE FRANKLIN GREENE HOCKING KNOX LICKING MADISON MARION MORROW PICKAWAY ROSS UNION WARREN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

MD 1613 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF THE MID ATLANTIC
Mesoscale Discussion 1613 NWS Storm Prediction Center Norman OK 1156 AM CDT Sun Jul 14 2024 Areas affected...Parts of the Mid Atlantic Concerning...Severe potential...Watch unlikely Valid 141656Z - 141930Z Probability of Watch Issuance...20 percent SUMMARY...Isolated damaging wind is possible this afternoon. DISCUSSION...A couple of strong storms have developed across southeast PA early this afternoon, within a warm, moist, and generally uncapped environment. The 12Z IAD/WAL soundings and recent forecast soundings depict a warm layer around 600 mb that will limit instability to some extent, but continued strong heating should allow for MLCAPE to increase into the 1500-2500 J/kg this afternoon. Low/midlevel flow is generally weak, but somewhat stronger upper-level flow could allow for some occasional modest storm organization, and the strongest storms will be capable of producing isolated damaging wind and small to near-severe hail. Storm coverage is somewhat more uncertain with southward extent, but at least isolated development is expected into parts of MD and eastern VA, where temperatures rising well into the 90s F and steepening low-level lapse rates will support an isolated damaging-wind threat with any robust updrafts later this afternoon. ..Dean/Hart.. 07/14/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OKX...PHI...AKQ...CTP...LWX... LAT...LON 38427793 39837661 40987540 41077456 40787409 39797426 38357576 37807645 37537763 37927807 38427793 Read more

WW 0532 Status Updates
STATUS REPORT ON WW 532 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WSW IND TO 30 SSW MIE TO 25 NW DAY TO 35 N DAY TO 15 SW TOL. ..LYONS..07/14/24 ATTN...WFO...IWX...IND...ILN...CLE... STATUS REPORT FOR WS 532 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS INC041-047-059-065-081-109-139-145-161-177-141940- IN . INDIANA COUNTIES INCLUDED ARE FAYETTE FRANKLIN HANCOCK HENRY JOHNSON MORGAN RUSH SHELBY UNION WAYNE OHC003-011-017-021-023-027-033-041-045-047-049-057-063-065-073- 083-089-091-097-101-109-113-117-129-135-137-141-149-159-165-175- 141940- OH . OHIO COUNTIES INCLUDED ARE ALLEN AUGLAIZE BUTLER CHAMPAIGN CLARK CLINTON CRAWFORD DELAWARE FAIRFIELD FAYETTE FRANKLIN GREENE HANCOCK HARDIN HOCKING KNOX LICKING LOGAN MADISON MARION MIAMI Read more

WW 0532 Status Updates
STATUS REPORT ON WW 532 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WSW IND TO 30 SSW MIE TO 25 NW DAY TO 35 N DAY TO 15 SW TOL. ..LYONS..07/14/24 ATTN...WFO...IWX...IND...ILN...CLE... STATUS REPORT FOR WS 532 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS INC041-047-059-065-081-109-139-145-161-177-141940- IN . INDIANA COUNTIES INCLUDED ARE FAYETTE FRANKLIN HANCOCK HENRY JOHNSON MORGAN RUSH SHELBY UNION WAYNE OHC003-011-017-021-023-027-033-041-045-047-049-057-063-065-073- 083-089-091-097-101-109-113-117-129-135-137-141-149-159-165-175- 141940- OH . OHIO COUNTIES INCLUDED ARE ALLEN AUGLAIZE BUTLER CHAMPAIGN CLARK CLINTON CRAWFORD DELAWARE FAIRFIELD FAYETTE FRANKLIN GREENE HANCOCK HARDIN HOCKING KNOX LICKING LOGAN MADISON MARION MIAMI Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun Jul 14 2024 Valid 151200Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MIDWEST INTO THE OHIO VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Strong to severe thunderstorms are likely from the Upper Midwest into the Mid Mississippi Valley and Upper Great Lakes region tomorrow (Monday). A focused corridor of damaging winds is possible. Isolated severe thunderstorms are also possible across the central Plains as well as south-central/southeast Arizona. ...Synopsis... A complex severe weather scenario is possible across portions of the Midwest tomorrow (Monday). Upper ridging will prevail across the western CONUS as broad cyclonic flow remains in place, centered over the Upper MS Valley. Multiple mid-level impulses will pivot around the cyclonic flow from the Midwest into the Northeast, with a surface lee trough and associated cold front poised to sweep southeastward into the Midwest and OH Valley regions. Multiple areas/rounds of thunderstorm development are expected from the Midwest to the Northeast, with preceding storms exhibiting potential influence on the evolution of subsequent convective complexes. Nonetheless, the latest high-resolution guidance consensus, general synoptic pattern, and regional climatology, all suggest that at least one focused round of organized severe thunderstorms should occur across the Midwest at some point from the late morning to late afternoon hours, perhaps accompanied by a focused corridor of strong to severe wind gusts. Meanwhile, surface high pressure will dominate the Intermountain west, with monsoonal mid-level moisture pivoting around the upper ridge, fostering multiple areas of high-based strong to isolated severe thunderstorms from the Desert Southwest to the central High Plains. ...Midwest into the OH Valley... Multiple convective scenarios may unfold across portions of the Midwest tomorrow, including the possibility of a focused corridor or of severe gusts produced by a bow-echo MCS. By late morning/early afternoon, a pronounced mid-level impulse will quickly traverse the region, overspreading a generally west-to-east oriented surface baroclinic zone. Along this boundary, upper 70s F surface dewpoints will be in place, that in tandem with surface heating, will boost MLCAPE to at least 3500-4500 J/kg. Given strong mid-level westerly flow accompanying the impulse, appreciable low-level shear and modest deep-layer shear is expected, characterized by enlarged and curved low-level hodographs, but short hodographs aloft. This environment climatologically favors the development of a progressive bow-echo capable of producing a focused corridor of severe gusts (perhaps exceeding 75 mph in spots). Furthermore, some HREF members also depict possible bow echo development. However, there are some uncertainties regarding how the bow echo could form, with some members showing a bow echo approaching from MN/IA from Day 1 convection, or from new convective development over central IA. Since multiple rounds of preceding convection may also influence the position of the baroclinic zone and associated gradient of strong to extreme buoyancy, there is some uncertainty as to exactly where a bow echo would materialize and track. A Category 3/Enhanced risk has been introduced in the general region where a bow echo may form, and these highlights may need some adjustments during the Day 1 Outlook to account for baroclinic zone placement, or impacts from preceding convection. 5 percent tornado probabilities have also been added where a bow echo would most likely reach mature stage, where line-end and leading-line/system-scale mesovortices may foster leading-line QLCS tornado potential. However, even in the event that a bow echo does not materialize, a surface cold front will approach the Midwest tomorrow, contributing to linear convective initiation amid strong/extreme buoyancy, where severe gusts will still be of concern. ...Portions of the Northeast... The first in a series of mid-level impulses traversing the cyclonic flow aloft will approach the northern Appalachians by late morning/early afternoon, contributing to increasing thunderstorm coverage during the day. Surface dewpoints exceeding 70 F in several areas, along with modest mid-level lapse rates (perhaps approaching 7 C/km in spots), will result in widespread 1500-2500 J/kg MLCAPE. Stronger flow aloft will likely remain west into the OH Valley though, so vertical shear should be modest at best (i.e. bulk effective shear values around 25 kts). Pulse cellular and occasional multicell complexes are possible, accompanied by mainly a damaging gust threat. Storms should gradually weaken around or after sunset. ...Portions of the Central High Plains... Upslope low-level flow by late afternoon/early evening, in tandem with peak afternoon heating, will encourage at least scattered thunderstorm development along the lee of the Rocky Mountains. 30-40 kts of westerly 500 mb flow pivoting around the north side an anticyclone will assist in thunderstorms quickly moving into the central High Plains. Here, thunderstorms will be preceded by a well mixed boundary layer extending up to 700 mb. Surface to 500 mb lapse rates should be in the 8.5-9.5 C/km range, which favors deep-layer convective mixing and associated potential for severe gusts. A Category 2/Slight Risk has been added to portions of the central High Plains where thunderstorm clustering is expected to be greatest (based on the latest high-resolution guidance consensus), and where cold-pool mergers are most likely to occur. ...Portions of southern into central Arizona... Thunderstorms are expected to develop along the Mogollon Rim by afternoon peak heating in central AZ. Easterly mid-level flow pivoting around the south side of an anticyclone may assist the storms in moving off of the higher terrain, amid a well-mixed boundary layer. Surface temperatures approaching 100 F ahead of the storms, beneath the monsoonal mid-level moisture, will support MLCAPE exceeding 1000 J/kg in spots. Modest elongation of the hodographs may result in effective bulk shear values approaching 30 kts, which may support sustained multicellular clusters by late afternoon into early evening, accompanied by an isolated severe gust threat. ..Squitieri.. 07/14/2024 Read more