Severe Storms

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0406 PM CDT Sun Jul 27 2025 Valid 291200Z - 041200Z Broad ridging over the central US will continue to strengthen through much of the extended forecast period amplifying the upper-level flow pattern. As a result, broad troughing will deepen over the western US, allowing an increase in mid-level moisture. An active period of thunderstorms is expected from the Great basin to the Northwest through Midweek. Dry lightning and occasional dry/breezy conditions are likely. ...Northern Great Basin and Northwest... The broad troughing over the western US will continue to deepen as prominent ridging to the east further amplifies the flow pattern aloft. Within the broad troughing, several well-defined perturbations will approach the northern Great Basin and Northwest early next week. Starting late D2/Monday through D3/Tuesday, a shortwave trough will bring an initial surge of mid-level moisture northward across northern CA, NV into southern OR/ID. Isolated to widely scattered thunderstorms are likely along the Sierras and into the southern Cascades. With PWATs of 0.7-1 inches, relatively poor precipitation efficiency is expected given steep lapse rates. Isolated dry lightning is possible with these storms. Greater lightning chances continue D4/Wed into D5/Thursday as a second shortwave is expected to intensify across the Great Basin and Northwest. More widespread storm coverage is expected as moisture expands northward across much of the Cascades and northern Great Basin. MUCAPE near 1000 J/kg and strengthening meridional flow aloft could support some stronger storms with greater longevity. The exact convective evolution and areas of highest coverage remain unclear given the potential for lingering cloud cover and prior convection. However, scattered to numerous storms overspreading dry fuels beds will very likely pose a risk for lightning ignitions over the coming days. Expect further refinements in the 10% IsoDryT areas as convective details are resolved. ...Eastern Great Basin... To the south of the main shortwave trough, slight enhancement of south/southwesterly flow aloft could support stronger surface winds and low RH across parts of the eastern Great Basin and Western Slope D4/Wednesday and beyond. While uncertainty remains given model differences in timing/intensity of the upper-level system, elevated to locally critical fire-weather conditions are possible through the end of the week. ..Lyons.. 07/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Sun Jul 27 2025 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN/CENTRAL MINNESOTA AND FAR EASTERN SOUTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC STATES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the Upper Midwest to western Great Lakes. Other severe storms are also possible in parts of the northern Plains, central Appalachians, and Mid-Atlantic. ...20Z Update... Both the Slight and Enhanced risks were expanded slightly west-southwestward in eastern SD with this update. Here, the latest guidance has come into relatively good agreement, depicting convective development ahead of a gradually evolving surface low into this evening. Very steep deep-layer lapse rates/extreme surface-based buoyancy and 40-50 kt of effective shear will promote supercells/organized clusters capable of producing large hail and severe wind gusts. Farther east, the Marginal risk was expanded southward across southeastern NC into northern SC. Strong heating/destabilization will promote damaging wind gusts with any small thunderstorm clusters that evolve. ..Weinman.. 07/27/2025 .PREV DISCUSSION... /ISSUED 1200 PM CDT Sun Jul 27 2025/ ...Upper Midwest/western Great Lakes including MN/eastern SD... A convectively enhanced mid-level shortwave trough over northern/eastern North Dakota will continue generally eastward toward northern Minnesota, with a modest flattening of the downstream upper-level ridge into tonight. A modest deepening of the surface low will occur across eastern South Dakota toward the southwest Minnesota border vicinity, with intense thunderstorm development later today generally expected to focus along the southeastward-advancing front, although differential heating and a convectively aided cluster/possible MCV across northeast South Dakota at midday may also be factors. Given the strong buoyancy near/south of the front, and very steep lapse rates/elevated mixed layer impinging from the west-southwest, modestly strong wind profiles will be sufficient for intense supercell development with initial storms, including large hail potential (higher magnitudes possible especially eastern South Dakotas and southwest Minnesota) and some tornado risk. Multiple southeastward-moving clusters should evolve this evening with an increasing likelihood of damaging wind across southern Minnesota into western/northern Wisconsin. Portions of the region have been upgraded to an Enhanced Risk. ...Mid-Atlantic/Central Appalachians... Scattered afternoon thunderstorms will continue to increase regionally. Similar to previous days, mid-level lapse rates will be weak and considerable mid-level moisture will keep the overall potential somewhat limited/isolated. However, the strongest cells will be capable of occasional gusty/damaging winds, with a somewhat higher probability of wind damage seemingly existing across eastern Virginia where buoyancy will be greater. ...Montana... Strong heating will occur this afternoon across much of central/eastern Montana, where deep boundary-layer mixing will lead to inverted-v profiles. Scattered thunderstorms are forecast to develop along a corridor from southwest into central Montana by late afternoon. These high-based storms may pose a risk of a few severe-caliber wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Sun Jul 27 2025 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN/CENTRAL MINNESOTA AND FAR EASTERN SOUTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC STATES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the Upper Midwest to western Great Lakes. Other severe storms are also possible in parts of the northern Plains, central Appalachians, and Mid-Atlantic. ...20Z Update... Both the Slight and Enhanced risks were expanded slightly west-southwestward in eastern SD with this update. Here, the latest guidance has come into relatively good agreement, depicting convective development ahead of a gradually evolving surface low into this evening. Very steep deep-layer lapse rates/extreme surface-based buoyancy and 40-50 kt of effective shear will promote supercells/organized clusters capable of producing large hail and severe wind gusts. Farther east, the Marginal risk was expanded southward across southeastern NC into northern SC. Strong heating/destabilization will promote damaging wind gusts with any small thunderstorm clusters that evolve. ..Weinman.. 07/27/2025 .PREV DISCUSSION... /ISSUED 1200 PM CDT Sun Jul 27 2025/ ...Upper Midwest/western Great Lakes including MN/eastern SD... A convectively enhanced mid-level shortwave trough over northern/eastern North Dakota will continue generally eastward toward northern Minnesota, with a modest flattening of the downstream upper-level ridge into tonight. A modest deepening of the surface low will occur across eastern South Dakota toward the southwest Minnesota border vicinity, with intense thunderstorm development later today generally expected to focus along the southeastward-advancing front, although differential heating and a convectively aided cluster/possible MCV across northeast South Dakota at midday may also be factors. Given the strong buoyancy near/south of the front, and very steep lapse rates/elevated mixed layer impinging from the west-southwest, modestly strong wind profiles will be sufficient for intense supercell development with initial storms, including large hail potential (higher magnitudes possible especially eastern South Dakotas and southwest Minnesota) and some tornado risk. Multiple southeastward-moving clusters should evolve this evening with an increasing likelihood of damaging wind across southern Minnesota into western/northern Wisconsin. Portions of the region have been upgraded to an Enhanced Risk. ...Mid-Atlantic/Central Appalachians... Scattered afternoon thunderstorms will continue to increase regionally. Similar to previous days, mid-level lapse rates will be weak and considerable mid-level moisture will keep the overall potential somewhat limited/isolated. However, the strongest cells will be capable of occasional gusty/damaging winds, with a somewhat higher probability of wind damage seemingly existing across eastern Virginia where buoyancy will be greater. ...Montana... Strong heating will occur this afternoon across much of central/eastern Montana, where deep boundary-layer mixing will lead to inverted-v profiles. Scattered thunderstorms are forecast to develop along a corridor from southwest into central Montana by late afternoon. These high-based storms may pose a risk of a few severe-caliber wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Sun Jul 27 2025 Valid 272000Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN/CENTRAL MINNESOTA AND FAR EASTERN SOUTH DAKOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC STATES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the Upper Midwest to western Great Lakes. Other severe storms are also possible in parts of the northern Plains, central Appalachians, and Mid-Atlantic. ...20Z Update... Both the Slight and Enhanced risks were expanded slightly west-southwestward in eastern SD with this update. Here, the latest guidance has come into relatively good agreement, depicting convective development ahead of a gradually evolving surface low into this evening. Very steep deep-layer lapse rates/extreme surface-based buoyancy and 40-50 kt of effective shear will promote supercells/organized clusters capable of producing large hail and severe wind gusts. Farther east, the Marginal risk was expanded southward across southeastern NC into northern SC. Strong heating/destabilization will promote damaging wind gusts with any small thunderstorm clusters that evolve. ..Weinman.. 07/27/2025 .PREV DISCUSSION... /ISSUED 1200 PM CDT Sun Jul 27 2025/ ...Upper Midwest/western Great Lakes including MN/eastern SD... A convectively enhanced mid-level shortwave trough over northern/eastern North Dakota will continue generally eastward toward northern Minnesota, with a modest flattening of the downstream upper-level ridge into tonight. A modest deepening of the surface low will occur across eastern South Dakota toward the southwest Minnesota border vicinity, with intense thunderstorm development later today generally expected to focus along the southeastward-advancing front, although differential heating and a convectively aided cluster/possible MCV across northeast South Dakota at midday may also be factors. Given the strong buoyancy near/south of the front, and very steep lapse rates/elevated mixed layer impinging from the west-southwest, modestly strong wind profiles will be sufficient for intense supercell development with initial storms, including large hail potential (higher magnitudes possible especially eastern South Dakotas and southwest Minnesota) and some tornado risk. Multiple southeastward-moving clusters should evolve this evening with an increasing likelihood of damaging wind across southern Minnesota into western/northern Wisconsin. Portions of the region have been upgraded to an Enhanced Risk. ...Mid-Atlantic/Central Appalachians... Scattered afternoon thunderstorms will continue to increase regionally. Similar to previous days, mid-level lapse rates will be weak and considerable mid-level moisture will keep the overall potential somewhat limited/isolated. However, the strongest cells will be capable of occasional gusty/damaging winds, with a somewhat higher probability of wind damage seemingly existing across eastern Virginia where buoyancy will be greater. ...Montana... Strong heating will occur this afternoon across much of central/eastern Montana, where deep boundary-layer mixing will lead to inverted-v profiles. Scattered thunderstorms are forecast to develop along a corridor from southwest into central Montana by late afternoon. These high-based storms may pose a risk of a few severe-caliber wind gusts. Read more