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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun May 11 2025 Valid 112000Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS... ...SUMMARY... Scattered severe wind gusts are expected across the northern Rockies/Great Basin and the Montana High Plains from mid-afternoon into the evening. Isolated severe thunderstorms are also possible across the Southeast today through tonight. ...20Z Update... The only noteworthy change with this update was a southwestward expansion of the Slight Risk area into northern UT, driven by 15-percent severe wind probabilities. Here, ample diurnal heating has resulted in a deep/dry boundary layer supportive of scattered severe wind gusts accompanying high-based storms. Reference Severe Thunderstorm Watch #245 for more details. Farther east, isolated severe storms capable of producing locally damaging winds and marginally severe hail remain possible across the Southeast into this evening. Reference MCDs #766/767 for details. ..Weinman.. 05/11/2025 .PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/ ...Northern Rockies/High Plains and northeast Great Basin... Strengthening southwesterly flow aloft is anticipated throughout the day as the upper low off the Pacific Northwest coast progresses eastward and a lead shortwave trough pivots through OR/northern CA into the northern Rockies. Strong heating will help destabilize the airmass downstream from the northern Rockies into the northern High Plains. Large-scale ascent attendant to the approaching shortwave trough, coupled with orographic lift, will help initiate storms across the high terrain during the afternoon within this destabilized airmass. Environmental conditions suggest some supercells are possible with this initial development, with damaging gusts and isolated hail as the primary risk. A low-probability corridor of tornado potential exists across southeast ID. The storms should encounter an increasingly mixed environment with eastern/northeastern extent into central MT, with strong gusts becoming the primary severe hazard as storms trend towards more outflow-dominant linear structures. ...Southeast States... Recent satellite imagery and surface observations continue to show the vertically stacked low over the Lower MS Valley, with broad swath of southwesterly flow extending south and east of this low from the central Gulf into FL. Surface features have become increasingly diffuse across the Southeast and FL over the past two days given the persistence of this low and associated precipitation, but recent surface analysis shows a weak and wavy stationary boundary extending from the low over the ArkLaMiss southeastward to the AL/FL Panhandle border before arcing back northeastward across southern GA. Scattered thunderstorms are ongoing and the general expectation is for scattered to numerous thunderstorms to persist across much of the region throughout the day. Widespread cloudiness should limit heating, but ample low-level moisture will still support modest buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some transient storm organization, but in general convection is expected to be disorganized, outflow-dominated multicells. Even so, isolated damaging gusts are possible. Some low-probability tornado potential exists as well, particularly along the stationary boundary across southern GA around 00Z. Farther northwest across AL/MS and into eastern AR, the airmass is forecast to destabilize this afternoon as heating occurs beneath cool temperatures aloft. Even with the cooler temperature aloft, overall buoyancy will be modest given the somewhat cool low to mid-level thermodynamic profile. Even so, a nearly unidirectional southeasterly wind profile with moderate deep-layer speed shear could support brief updraft organization. As a result, a few cells may briefly produce marginally severe hail and locally strong gusts, and possibly some funnel/brief tornado potential, from late afternoon through early/mid-evening. Read more

MD 0764 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SALT LAKE VICINITY
Mesoscale Discussion 0764 NWS Storm Prediction Center Norman OK 0130 PM CDT Sun May 11 2025 Areas affected...Salt Lake Vicinity Concerning...Severe potential...Watch unlikely Valid 111830Z - 112030Z Probability of Watch Issuance...20 percent SUMMARY...Severe wind gusts will be possible this afternoon with high-based showers and embedded thunderstorms. DISCUSSION...With temperatures rising into the low/mid 80s F in the vicinity of Salt Lake, high-based showers and isolated thunderstorms have deepened over the last hour. A few of these storms have produced 58-63 mph measured gusts in Tooele/Salt Lake Counties. While low-level wind fields are not overly strong, the 9.2 C/km 700-500 mb lapse rate observed in this mornings 12Z SLC sounding, coupled with steep low-level lapse rates and high surface dewpoint depressions, will continue to support strong diabatically driven downdrafts. Severe wind gusts will remain possible through the afternoon in association with this weak, disorganized convection. ..Wendt/Mosier.. 05/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SLC...PIH... LAT...LON 40601390 40971401 41411368 41841283 42061198 41861165 40971159 40241175 40011215 39861291 39981339 40601390 MOST PROBABLE PEAK WIND GUST...65-80 MPH Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Sun May 11 2025 Valid 121200Z - 131200Z ...Southwest... An accelerating subtropical jet across the Desert Southwest atop a deep, dry boundary layer will support breezy afternoon winds across southeastern Arizona and southwestern New Mexico, where fuels remain relatively dry amid ongoing severe/extreme drought. Expanded area of elevated fire weather conditions to account for higher expected winds across south-central Arizona for Monday. ...Northern Plains and Upper-Midwest... A broad area of dry, southerly return flow amid fuels with ERC values above the 97th percentile will support elevated fire weather conditions across the Northern Plains and Upper-Midwest. Record setting temperatures in the lower to upper 90s are again expected across the region. Locally critical fire weather conditions are most likely from a corridor of enhanced south winds from north-central Nebraska to northwestern Minnesota. Model guidance is still somewhat inconsistent with overlapping low relative humidity so continued uncertainty precluded adding Critical highlights at this time. ..Williams.. 05/11/2025 .PREV DISCUSSION... /ISSUED 0149 AM CDT Sun May 11 2025/ ...Synopsis... The partially blocked upper-air pattern over the US will begin to breakdown early in the new week as a trough deepens over the western US. Strong mid-level flow will gradually move into the Plains, as upper ridging moves eastward. Strong lee troughing/cyclogensisis will support gusty south/westerly winds over the High Plains. Fire-weather conditions are expected across the Great Plains and Southwest Monday afternoon and evening. ...Northern Plains and Midwest... Strong southerly low-level flow will continue Monday as the upper trough ejects eastward and the surface low deepens over MT and the western Dakotas. Surface winds of 25-30 mph are again expected across much of MT, the Dakotas and into parts of NE/MN/IA. However, RH values should begin to increase as low-level moisture is advected northward and mid-level cloud cover reduces solar heating. While still relatively dry below 30%, RH values do not appear critical. This will favor widespread elevated and pockets of locally critical conditions Monday afternoon. ...Southwest... As the troughing over the west gradually deepens, strong mid-level flow will begin to move eastward over the southern Rockies and Southwest. Westerly downslope flow is likely across parts of eastern AZ and western NM Monday. With gusts of 15-20 mph and RH below 15%, several hours of elevated fire-weather conditions are likely within dry fuels that have supported recent fire activity. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Sun May 11 2025 Valid 121200Z - 131200Z ...Southwest... An accelerating subtropical jet across the Desert Southwest atop a deep, dry boundary layer will support breezy afternoon winds across southeastern Arizona and southwestern New Mexico, where fuels remain relatively dry amid ongoing severe/extreme drought. Expanded area of elevated fire weather conditions to account for higher expected winds across south-central Arizona for Monday. ...Northern Plains and Upper-Midwest... A broad area of dry, southerly return flow amid fuels with ERC values above the 97th percentile will support elevated fire weather conditions across the Northern Plains and Upper-Midwest. Record setting temperatures in the lower to upper 90s are again expected across the region. Locally critical fire weather conditions are most likely from a corridor of enhanced south winds from north-central Nebraska to northwestern Minnesota. Model guidance is still somewhat inconsistent with overlapping low relative humidity so continued uncertainty precluded adding Critical highlights at this time. ..Williams.. 05/11/2025 .PREV DISCUSSION... /ISSUED 0149 AM CDT Sun May 11 2025/ ...Synopsis... The partially blocked upper-air pattern over the US will begin to breakdown early in the new week as a trough deepens over the western US. Strong mid-level flow will gradually move into the Plains, as upper ridging moves eastward. Strong lee troughing/cyclogensisis will support gusty south/westerly winds over the High Plains. Fire-weather conditions are expected across the Great Plains and Southwest Monday afternoon and evening. ...Northern Plains and Midwest... Strong southerly low-level flow will continue Monday as the upper trough ejects eastward and the surface low deepens over MT and the western Dakotas. Surface winds of 25-30 mph are again expected across much of MT, the Dakotas and into parts of NE/MN/IA. However, RH values should begin to increase as low-level moisture is advected northward and mid-level cloud cover reduces solar heating. While still relatively dry below 30%, RH values do not appear critical. This will favor widespread elevated and pockets of locally critical conditions Monday afternoon. ...Southwest... As the troughing over the west gradually deepens, strong mid-level flow will begin to move eastward over the southern Rockies and Southwest. Westerly downslope flow is likely across parts of eastern AZ and western NM Monday. With gusts of 15-20 mph and RH below 15%, several hours of elevated fire-weather conditions are likely within dry fuels that have supported recent fire activity. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Sun May 11 2025 Valid 121200Z - 131200Z ...Southwest... An accelerating subtropical jet across the Desert Southwest atop a deep, dry boundary layer will support breezy afternoon winds across southeastern Arizona and southwestern New Mexico, where fuels remain relatively dry amid ongoing severe/extreme drought. Expanded area of elevated fire weather conditions to account for higher expected winds across south-central Arizona for Monday. ...Northern Plains and Upper-Midwest... A broad area of dry, southerly return flow amid fuels with ERC values above the 97th percentile will support elevated fire weather conditions across the Northern Plains and Upper-Midwest. Record setting temperatures in the lower to upper 90s are again expected across the region. Locally critical fire weather conditions are most likely from a corridor of enhanced south winds from north-central Nebraska to northwestern Minnesota. Model guidance is still somewhat inconsistent with overlapping low relative humidity so continued uncertainty precluded adding Critical highlights at this time. ..Williams.. 05/11/2025 .PREV DISCUSSION... /ISSUED 0149 AM CDT Sun May 11 2025/ ...Synopsis... The partially blocked upper-air pattern over the US will begin to breakdown early in the new week as a trough deepens over the western US. Strong mid-level flow will gradually move into the Plains, as upper ridging moves eastward. Strong lee troughing/cyclogensisis will support gusty south/westerly winds over the High Plains. Fire-weather conditions are expected across the Great Plains and Southwest Monday afternoon and evening. ...Northern Plains and Midwest... Strong southerly low-level flow will continue Monday as the upper trough ejects eastward and the surface low deepens over MT and the western Dakotas. Surface winds of 25-30 mph are again expected across much of MT, the Dakotas and into parts of NE/MN/IA. However, RH values should begin to increase as low-level moisture is advected northward and mid-level cloud cover reduces solar heating. While still relatively dry below 30%, RH values do not appear critical. This will favor widespread elevated and pockets of locally critical conditions Monday afternoon. ...Southwest... As the troughing over the west gradually deepens, strong mid-level flow will begin to move eastward over the southern Rockies and Southwest. Westerly downslope flow is likely across parts of eastern AZ and western NM Monday. With gusts of 15-20 mph and RH below 15%, several hours of elevated fire-weather conditions are likely within dry fuels that have supported recent fire activity. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Sun May 11 2025 Valid 121200Z - 131200Z ...Southwest... An accelerating subtropical jet across the Desert Southwest atop a deep, dry boundary layer will support breezy afternoon winds across southeastern Arizona and southwestern New Mexico, where fuels remain relatively dry amid ongoing severe/extreme drought. Expanded area of elevated fire weather conditions to account for higher expected winds across south-central Arizona for Monday. ...Northern Plains and Upper-Midwest... A broad area of dry, southerly return flow amid fuels with ERC values above the 97th percentile will support elevated fire weather conditions across the Northern Plains and Upper-Midwest. Record setting temperatures in the lower to upper 90s are again expected across the region. Locally critical fire weather conditions are most likely from a corridor of enhanced south winds from north-central Nebraska to northwestern Minnesota. Model guidance is still somewhat inconsistent with overlapping low relative humidity so continued uncertainty precluded adding Critical highlights at this time. ..Williams.. 05/11/2025 .PREV DISCUSSION... /ISSUED 0149 AM CDT Sun May 11 2025/ ...Synopsis... The partially blocked upper-air pattern over the US will begin to breakdown early in the new week as a trough deepens over the western US. Strong mid-level flow will gradually move into the Plains, as upper ridging moves eastward. Strong lee troughing/cyclogensisis will support gusty south/westerly winds over the High Plains. Fire-weather conditions are expected across the Great Plains and Southwest Monday afternoon and evening. ...Northern Plains and Midwest... Strong southerly low-level flow will continue Monday as the upper trough ejects eastward and the surface low deepens over MT and the western Dakotas. Surface winds of 25-30 mph are again expected across much of MT, the Dakotas and into parts of NE/MN/IA. However, RH values should begin to increase as low-level moisture is advected northward and mid-level cloud cover reduces solar heating. While still relatively dry below 30%, RH values do not appear critical. This will favor widespread elevated and pockets of locally critical conditions Monday afternoon. ...Southwest... As the troughing over the west gradually deepens, strong mid-level flow will begin to move eastward over the southern Rockies and Southwest. Westerly downslope flow is likely across parts of eastern AZ and western NM Monday. With gusts of 15-20 mph and RH below 15%, several hours of elevated fire-weather conditions are likely within dry fuels that have supported recent fire activity. ...Please see www.spc.noaa.gov/fire for graphic product... Read more