Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CDT Tue Aug 12 2025 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER GREAT LAKES/MIDWEST...AND PORTIONS OF THE SOUTHWEST... ...SUMMARY... Strong to occasionally severe thunderstorms may impact parts of the upper Great Lakes/Midwest today with both damaging winds and hail possible. Gusty winds may also occur over southeast Arizona and southwest New Mexico. ...Great Lakes/Midwest... A band of thunderstorms associated with an MCV tracked northeastward across parts of IA into northern IL and southern WI early this morning while remaining mostly sub-severe. Still, there may be some potential for strong to locally damaging winds with this activity as it continues northeastward across Lake Michigan into parts of Lower MI this morning/early afternoon as daytime heating gradually destabilizes the boundary layer. Otherwise, additional convection should develop later this afternoon along/ahead of a weak front over parts of WI and the U.P. of MI as the southern portion of a mid/upper-level trough moves eastward over the Upper Midwest/Great Lakes. Instability is forecast to remain fairly modest ahead of the front, but enough deep-layer shear should exist to support some organized convection. Initial cells may be capable of producing marginally severe hail, before clustering potentially increases the threat for occasional strong to damaging winds. A separate area of thunderstorms is forecast to develop this afternoon farther south and ahead of the front from portions of the Midwest into Lower MI. While this region will have relatively weaker mid-level westerly flow and related deep-layer shear compared to locations farther north, greater low-level moisture and instability are expected to be present. As low-level lapse rates become steepened with diurnal heating of the moist airmass, loosely organized clusters may become capable of producing isolated damaging winds as they spread generally east-northeastward through the afternoon and early evening. ...Southwest... Strong daytime heating should encourage diurnally driven convection over the higher terrain of southeast AZ and southwest NM this afternoon. With weak flow aloft and negligible shear, thunderstorms should drift slowly southward. Still, occasional gusty winds may occur with the more robust convection given steepened lapse rates. ..Gleason/Leitman.. 08/12/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0311 AM CDT Tue Aug 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... From Friday/D4 into Saturday/D5, an upper low will move from Manitoba across Hudson Bay and into Quebec. Moderate midlevel westerlies will exist over the far northern Plains to Upper Great Lakes during this period, with gradual weakening. An upper high will also be centered over the mid MS Valley, while a weak midlevel trough with cool air aloft slowly departs the Great Basin. At the surface, a front is forecast to stall on Friday/D4 from northern NE across southern MN and into northern WI, with a moist and unstable air mass remaining to the south. This front will remain over roughly the same zone into Saturday/D5, and perhaps as late as Sunday/D6. Given that the moist and unstable air mass will persist over parts of the northern Plains/Upper MS Valley, and minor ripples in the flow are hinted at by several models, areas of storms are expected. However, storm/MCS corridors are difficult to pinpoint this far out. In general, the area from SD into WI will bear watching for wind potential. From Sunday/D6 onward, an upper ridge is expected to build over much of the western and central states, with a reduction in severe potential overall. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PRIMARILY FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Discussion... On Thursday, a shortwave trough will continue eastward into the northern Plains during the day, with primary upper low well north into Canada. The southern periphery of this wave will move across ND and northern MN late day and overnight, with cooling aloft and increasing midlevel winds of 40-50 kt. At the surface, a cold front will be located from eastern ND into western SD during the afternoon, and will move into northern MN overnight. Southwest winds will bring moisture northward ahead of the front, with moderate instability forecast. Effective shear of 40-50 kt will develop late as the upper wave approaches and low-level jet increases. Storms are most likely to form around 00Z along the deeper cold front over eastern ND, and progress across northwest MN during the evening. Large hail appears likely as storm mode should be cellular. Strong heating into central SD may also yield isolated cells a bit farther south than forecast by many models, also with large hail threat. ..Jewell.. 08/12/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PRIMARILY FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Discussion... On Thursday, a shortwave trough will continue eastward into the northern Plains during the day, with primary upper low well north into Canada. The southern periphery of this wave will move across ND and northern MN late day and overnight, with cooling aloft and increasing midlevel winds of 40-50 kt. At the surface, a cold front will be located from eastern ND into western SD during the afternoon, and will move into northern MN overnight. Southwest winds will bring moisture northward ahead of the front, with moderate instability forecast. Effective shear of 40-50 kt will develop late as the upper wave approaches and low-level jet increases. Storms are most likely to form around 00Z along the deeper cold front over eastern ND, and progress across northwest MN during the evening. Large hail appears likely as storm mode should be cellular. Strong heating into central SD may also yield isolated cells a bit farther south than forecast by many models, also with large hail threat. ..Jewell.. 08/12/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PRIMARILY FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Discussion... On Thursday, a shortwave trough will continue eastward into the northern Plains during the day, with primary upper low well north into Canada. The southern periphery of this wave will move across ND and northern MN late day and overnight, with cooling aloft and increasing midlevel winds of 40-50 kt. At the surface, a cold front will be located from eastern ND into western SD during the afternoon, and will move into northern MN overnight. Southwest winds will bring moisture northward ahead of the front, with moderate instability forecast. Effective shear of 40-50 kt will develop late as the upper wave approaches and low-level jet increases. Storms are most likely to form around 00Z along the deeper cold front over eastern ND, and progress across northwest MN during the evening. Large hail appears likely as storm mode should be cellular. Strong heating into central SD may also yield isolated cells a bit farther south than forecast by many models, also with large hail threat. ..Jewell.. 08/12/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PRIMARILY FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Discussion... On Thursday, a shortwave trough will continue eastward into the northern Plains during the day, with primary upper low well north into Canada. The southern periphery of this wave will move across ND and northern MN late day and overnight, with cooling aloft and increasing midlevel winds of 40-50 kt. At the surface, a cold front will be located from eastern ND into western SD during the afternoon, and will move into northern MN overnight. Southwest winds will bring moisture northward ahead of the front, with moderate instability forecast. Effective shear of 40-50 kt will develop late as the upper wave approaches and low-level jet increases. Storms are most likely to form around 00Z along the deeper cold front over eastern ND, and progress across northwest MN during the evening. Large hail appears likely as storm mode should be cellular. Strong heating into central SD may also yield isolated cells a bit farther south than forecast by many models, also with large hail threat. ..Jewell.. 08/12/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PRIMARILY FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Discussion... On Thursday, a shortwave trough will continue eastward into the northern Plains during the day, with primary upper low well north into Canada. The southern periphery of this wave will move across ND and northern MN late day and overnight, with cooling aloft and increasing midlevel winds of 40-50 kt. At the surface, a cold front will be located from eastern ND into western SD during the afternoon, and will move into northern MN overnight. Southwest winds will bring moisture northward ahead of the front, with moderate instability forecast. Effective shear of 40-50 kt will develop late as the upper wave approaches and low-level jet increases. Storms are most likely to form around 00Z along the deeper cold front over eastern ND, and progress across northwest MN during the evening. Large hail appears likely as storm mode should be cellular. Strong heating into central SD may also yield isolated cells a bit farther south than forecast by many models, also with large hail threat. ..Jewell.. 08/12/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ..Moore.. 08/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ..Moore.. 08/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ..Moore.. 08/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ..Moore.. 08/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ..Moore.. 08/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ..Moore.. 08/12/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more