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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Fri Jul 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MIDWEST AND PARTS OF THE MID-ATLANTIC... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a couple of tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and North Carolina this afternoon. ...20Z Update... The primary change to the Day 1 20Z Convective Outlook update was to make minor eastward expansions of wind probabilities into eastern IA, as some of the latest convection allowing guidance depicts an MCS persisting into this region. Otherwise, the previous forecast (see below) remains on track, with very small adjustments made to thunder/severe probabilities to account for observational trends and/or guidance consensus updates. ..Squitieri.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1106 AM CDT Fri Jul 18 2025/ ...Virginia/North Carolina to the Mid-South... Late morning surface analysis places a stationary front draped from west to east from the mid MS Valley eastward into the Mid-Atlantic states. Visible satellite/radar mosaic imagery shows a couple of weak MCVs moving east over the northern VA/MD vicinity and over far eastern KY. The latter disturbance will probably prove instrumental in aiding storm development across VA into northern NC this afternoon. South of the front, rich low-level moisture and heating will act to offset weak mid-level lapse rates and yield moderate to strong buoyancy from southeast MO eastward to the Mid-Atlantic coast. Early indications of a swelling cumulus field over the WV/VA mountains will gradually evolve into a cluster of storms as convective inhibition continues to erode through early afternoon. Other clusters of storms will develop and move west to east given marginal deep-layer mean westerly flow. Although small hail 0.50-1.00 inch in diameter is possible with the strongest cores, the primary hazard with the stronger storms will be damaging gusts (50-65 mph) with the more intense water-loaded downdrafts. This activity will likely diminish by the early to mid evening. ...South Dakota/Nebraska into Minnesota/Iowa... Gradual low-level moistening is forecast through this evening ahead of a weak front forecast to be in place over the eastern Dakotas into western NE. An initially appreciable capping inversion will inhibit surface-based storm development until heating gradually weakens inhibition by late afternoon. A very unstable airmass is forecast by late afternoon/early evening, but nebulous forcing lends uncertainty in terms of storm development/timing. Models suggest storms will primarily develop this evening associated with strengthening low-level theta-e advection. Supercells are possible early in the convective life cycle with a risk for all hazards, including the possibility for a couple of tornadoes, but large hail may be the main hazard. Upscale growth into a cluster or MCS is possible near the terminus of a southwesterly 850-mb LLJ with severe gusts the becoming the primary threat. Models vary considerably whether storm intensity is maintained through much of the overnight and beyond the Day-1 period, or if a gradual diminishing in severe occurs. ...Great Basin into Wyoming and Far Southern Montana... Initially high-based convection should develop this afternoon across parts of the Great Basin into WY as modest ascent associated with a weak/low-amplitude mid-level impulse spreads eastward across these areas. Steep low/mid-level lapse rates and a deep, very well-mixed boundary layer should support isolated severe gusts with the stronger thunderstorms. Somewhat greater low-level moisture should be present this afternoon across parts of southern MT into northern/eastern WY, generally along/east of the Bighorn/Laramie Mountains. Isolated severe hail may occur with marginal supercells given greater instability/shear forecast across these areas. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 PM CDT Fri Jul 18 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID ATLANTIC WESTWARD ACROSS OHIO VALLEY AND INTO THE NORTHERN PLAINS... ...SUMMARY... Scattered strong storms with at least isolated severe potential will be possible from the Mid Atlantic into Ohio and Missouri Valleys and central Plains Sunday into Sunday night. ...Synopsis... A large area of cyclonic flow aloft will exist over the Northeast as an upper low moves southeastward across Quebec. To the south, and upper high will be centered over the Gulf Coast states, with an enhanced belt of midlevel westerlies across the Midwest. At the surface, a cold front will push southeastward across New England and toward the Mid Atlantic by late afternoon, with the western extension of this same boundary stalling into the Mid MO Valley. A very moist air mass will exist ahead of the main front, aiding episodes of strong storms from southern New England/Mid Atlantic Coast area, the OH Valley, and from SD into NE. ...Mid Atlantic/Northeast... Scattered thunderstorms are likely in association with the cold front beginning relatively early in the day. The air mass will be very moist, and heating will result in up to 1500 J/kg MUCAPE prior to the front moving offshore late in the day. Forecast soundings indicate poor lapse rates aloft, but strong gusts may occur with fast moving clusters of storms as far south as NJ. ...Central to northern Plains... A surface trough will deepen from eastern MT into western SD/NE/KS, with strong heating. Southeast surface winds will maintain moisture into the Dakotas and NE, with locally strong instability developing within a narrow uncapped zone. A few storms capable of large hail and localized wind damage may occur from late afternoon into early evening. Storm motions should remain relatively slow and severe threat localized as shear will remain marginal this far south. A small Slight Risk could be needed in later outlooks as precision increases. ...OH Valley... Early day storms near/north of the elongated front may linger across parts of IL/IN/OH, with a diurnal uptick as heating occurs from near St. Louis eastward across KY and into western VA. Poor lapse rates aloft and modest westerlies aloft suggest only localized severe potential within the broader thunderstorm area, with a few damaging downbursts possible. ..Jewell.. 07/18/2025 Read more

MD 1709 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHEAST MISSOURI TO WESTERN KENTUCKY
Mesoscale Discussion 1709 NWS Storm Prediction Center Norman OK 1220 PM CDT Fri Jul 18 2025 Areas affected...Southeast Missouri to western Kentucky Concerning...Severe potential...Watch unlikely Valid 181720Z - 181915Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorms developing from southeast Missouri to western Kentucky will pose a risk of damaging winds through late afternoon, but watch issuance is not expected. DISCUSSION...Thunderstorms are in the early stages of development to the west of I-55 in central/southeast MO within a diffuse stationary frontal zone. Through the afternoon, increasing southerly low-level winds will bolster low-level isentropic ascent, which in conjunction with peak heating, will promote additional thunderstorm development along the frontal zone into western KY. Weak winds within the lowest 9 km will limit overall storm organization/longevity and promote mainly multicell clusters. As such, the potential for a robust, prolonged severe threat is limited. However, MLCAPE values approaching 3500 J/kg by late afternoon, combined with equilibrium levels near 14-15 km, PWAT values near 2 inches, and theta-e deficits near 25 K will promote strong water-loaded downdrafts capable of strong to severe downburst winds. The potential for sporadic damaging gusts should increase through late afternoon as thunderstorm coverage increases. ..Moore/Smith.. 07/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OHX...PAH...MEG...LSX...LZK...SGF... LAT...LON 38189121 37999061 37749010 37518948 37548871 37528830 37438788 37248766 36828764 36518781 36358815 36308881 36258948 36379014 36449090 36519130 36639159 36819182 37339219 37619229 37809231 38159213 38289165 38189121 Read more

MD 1708 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHERN TENNESSEE INTO CENTRAL EASTERN KENTUCKY
Mesoscale Discussion 1708 NWS Storm Prediction Center Norman OK 1208 PM CDT Fri Jul 18 2025 Areas affected...Northern Tennessee into central eastern Kentucky Concerning...Severe potential...Watch unlikely Valid 181708Z - 181915Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorm coverage is expected to increase through late afternoon across north-central Tennessee into central eastern Kentucky, but weak wind shear should limit overall longevity/intensity of storms. However, a few instances of damaging wind appear possible. DISCUSSION...Thunderstorm development is well underway across central KY and north-central TN along and south of a diffuse stationary frontal zone. Continued daytime heating and weak ascent across the region will promote an increase in thunderstorm coverage through late afternoon. Despite very moist/buoyant conditions (MLCAPE is already approaching 3000 J/kg), modest mid-level winds will limit the overall kinematic environment and the potential for organized convection and a more robust severe threat. Because of this, watch issuance is not expected; however, theta-e deficits on the order of 25-30 K along with PWAT values around 1.8 to 2.0 inches should promote strong water-loaded downdrafts and the potential for damaging/severe downburst winds with the deeper convective cores. The potential for sporadic damaging winds should increase in tandem with the coverage of disorganized multicells. ..Moore/Smith.. 07/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MRX...JKL...LMK...OHX...PAH... LAT...LON 38068373 37918319 37548293 37048288 36638304 36288345 36008404 35758497 35758578 35768635 35848685 36168723 36518749 36928755 37168748 37428723 37648640 38018448 38068373 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0152 PM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z Tomorrow's (Day 2/Saturday) fire weather forecast remains largely on-track, with only modest areal adjustments needed to the outlook areas based on the latest ensemble forecast guidance. The primary change with this update was to expand the Elevated area across the northern Great Basin a bit farther north/northeast into southwest Montana and also westward into portions of northern California and southeast Oregon. Locally critical conditions are most likely across the wind-prone portions of the Snake River Plain and Upper Snake River Valley in Idaho, where localized areas of sustained surface winds exceeding 20 mph and RH values less than 15% are possible for several hours during the afternoon/evening. Please see the discussion below for more information on tomorrow's fire weather forecast. ..Elliott.. 07/18/2025 .PREV DISCUSSION... /ISSUED 1218 AM CDT Fri Jul 18 2025/ ...Synopsis... A low-amplitude upper level trough will pivot through the Northwest on Saturday. In the lee of the northern Rockies, a surface low will deepen in central Montana. Mid-level moisture will be pushed slightly southward and eastward by the sagging upper trough in the Northwest. Additional thunderstorms are possible in the parts of the central/eastern Great Basin. However, PWAT values and slower storm motions do not suggest a significant threat for new ignitions. ...Columbia Basin and northern Nevada/southern Idaho... Elevated fire weather conditions are again expected in the Columbia Basin. With the core of the mid-level jet primarily being east of the region by the afternoon, the overall setup should favor slightly less strong wind coverage. Winds of 15-20 mph are still possible. RH may be a touch higher than on Friday with around 20% being probable during the afternoon. With the trough sagging southward and the surface low deepening, a zone of 15-20 mph (locally higher) winds is possible in parts of the northern Great Basin. RH could fall as low as 10-15% by the afternoon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more