Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Fri Aug 08 2025 Valid 082000Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT FOR PARTS OF THE UPPER MIDWEST AND THE CENTRAL HIGH PLAINS... ...SUMMARY... Scattered severe thunderstorms with damaging winds, large hail, and a couple tornadoes are possible this evening and tonight across parts of the Upper Midwest and the central High Plains. ...20z Update... ...Upper Midwest... Latest radar/satellite trends show a residual storm complex and cloud cover over northeast Minnesota. This activity continues to diminish, with some weak convection developing in proximity. Surface observations suggest little evidence of extensive outflow in its wake, though southeasterly surface winds are prevalent across much of Minnesota where cloud cover has remained persistent. To the west, a cold front continues to advance eastward and is beginning to impinge upon portions of northwest Minnesota into eastern South Dakota. Storm initiation is still expected by early evening along the cold front in eastern South/North Dakota, with a quick transition from cellular to linear modes. Not much has changed in terms of expectations from the prior outlook. As this activity grows upscale and matures, some potential for a more concentrated corridor of damaging winds may emerge in far northeast Minnesota, but details remain uncertain and will be reevaluated in the 01z Outlook. With that said, given the potential for upscale growth, have expanded the Marginal area (Level 1 of 5) eastward into portions of northeast Iowa and vicinity. ...Southwest South Dakota/Nebraska Panhandle... Surface observations and SPC mesoanalysis show a post-frontal airmass with enough residual moisture to allow for modest destabilization across the region. Recent CAM guidance suggests the potential for isolated convection to develop in the high terrain of eastern Wyoming and persist eastward into southwest South Dakota and the Nebraska Panhandle. Given effective shear of 45-50 kt in association with enhanced flow along the southern periphery of the upper-level trough, a few supercell storms are possible with severe hail/wind the main threats. Therefore, have introduced a Slight Risk (Level 2 of 5) to encompass this potential. ..Karstens/Lyons.. 08/08/2025 .PREV DISCUSSION... /ISSUED 1118 AM CDT Fri Aug 08 2025/ ...Upper Midwest... The large convective complex that affected ND/MN last night has mostly dissipated, with the associated shortwave trough lifting across the MN Arrowhead. Shortwave ridging is occurring in the wake of this system, which should suppress deep convective development for most of the afternoon. Southeasterly low-level winds and daytime heating across much of MN and eastern SD will help re-establish a very moist/unstable air mass (MLCAPE > 4000 J/kg) by late afternoon. Another strong shortwave trough now over WY will begin affecting the ND/MN area by that time, with an associated cold front approaching the area. Scattered thunderstorms are expected to form along/ahead of the front, mainly after 00z. Deep-layer shear will support supercell storm structures capable of large hail and damaging wind gusts. A few tornadoes are also possible, given the very moist environment and backed low-level winds. However, many of the storms may be elevated and behind the front. Activity will persist deep into the night, spreading eastward across MN and into parts of northern WI and western Upper MI. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Fri Aug 08 2025 Valid 082000Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT FOR PARTS OF THE UPPER MIDWEST AND THE CENTRAL HIGH PLAINS... ...SUMMARY... Scattered severe thunderstorms with damaging winds, large hail, and a couple tornadoes are possible this evening and tonight across parts of the Upper Midwest and the central High Plains. ...20z Update... ...Upper Midwest... Latest radar/satellite trends show a residual storm complex and cloud cover over northeast Minnesota. This activity continues to diminish, with some weak convection developing in proximity. Surface observations suggest little evidence of extensive outflow in its wake, though southeasterly surface winds are prevalent across much of Minnesota where cloud cover has remained persistent. To the west, a cold front continues to advance eastward and is beginning to impinge upon portions of northwest Minnesota into eastern South Dakota. Storm initiation is still expected by early evening along the cold front in eastern South/North Dakota, with a quick transition from cellular to linear modes. Not much has changed in terms of expectations from the prior outlook. As this activity grows upscale and matures, some potential for a more concentrated corridor of damaging winds may emerge in far northeast Minnesota, but details remain uncertain and will be reevaluated in the 01z Outlook. With that said, given the potential for upscale growth, have expanded the Marginal area (Level 1 of 5) eastward into portions of northeast Iowa and vicinity. ...Southwest South Dakota/Nebraska Panhandle... Surface observations and SPC mesoanalysis show a post-frontal airmass with enough residual moisture to allow for modest destabilization across the region. Recent CAM guidance suggests the potential for isolated convection to develop in the high terrain of eastern Wyoming and persist eastward into southwest South Dakota and the Nebraska Panhandle. Given effective shear of 45-50 kt in association with enhanced flow along the southern periphery of the upper-level trough, a few supercell storms are possible with severe hail/wind the main threats. Therefore, have introduced a Slight Risk (Level 2 of 5) to encompass this potential. ..Karstens/Lyons.. 08/08/2025 .PREV DISCUSSION... /ISSUED 1118 AM CDT Fri Aug 08 2025/ ...Upper Midwest... The large convective complex that affected ND/MN last night has mostly dissipated, with the associated shortwave trough lifting across the MN Arrowhead. Shortwave ridging is occurring in the wake of this system, which should suppress deep convective development for most of the afternoon. Southeasterly low-level winds and daytime heating across much of MN and eastern SD will help re-establish a very moist/unstable air mass (MLCAPE > 4000 J/kg) by late afternoon. Another strong shortwave trough now over WY will begin affecting the ND/MN area by that time, with an associated cold front approaching the area. Scattered thunderstorms are expected to form along/ahead of the front, mainly after 00z. Deep-layer shear will support supercell storm structures capable of large hail and damaging wind gusts. A few tornadoes are also possible, given the very moist environment and backed low-level winds. However, many of the storms may be elevated and behind the front. Activity will persist deep into the night, spreading eastward across MN and into parts of northern WI and western Upper MI. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 PM CDT Fri Aug 08 2025 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTH-CENTRAL HIGH PLAINS TO THE CENTRAL GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible from the south-central High Plains to the central Great Lakes, mainly Sunday afternoon and evening. ...South-central High Plains to the central Great Lakes... Low severe probabilities are evident on Sunday across a large swath of the central states along the effective baroclinic zone which will be modulated by overnight convective regimes. These should be in a decaying state, centered over the central High Plains and from the Lower MO Valley to the Lake MI vicinity. Diurnal destabilization in the wake of morning activity, especially pronounced to the south of remnant convective outflows, should foster ample buoyancy in a swath from the lee of the southern Rockies towards IN/Lower MI. Low-amplitude mid-level troughing should persist across the south-central High Plains, despite progged dampening of an embedded shortwave impulse that should cross the southern Rockies early Sunday. This will yield favorable deep-layer shear for supercells in eastern CO and the Raton Mesa vicinity, supportive of isolated large hail and severe gusts. Progressively weaker deep-layer shear is expected with southern/eastern extent owing to a persistent mid-level ridge from the southern High Plains to the Lower Great Lakes. But with signals for fairly extensive afternoon to evening storm coverage along the baroclinic zone, several clusters of mainly weakly organized convection seem plausible. This should support a primary threat of strong to localized severe gusts from KS to MI. ..Grams.. 08/08/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...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 0221 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z The D2 Fire Weather Outlook was updated to remove isolated dry thunderstorm chances across Montana where fuels are not receptive to fire spread. The isolated dry thunderstorm area was reduced across portions of eastern Arizona where HREF probabilities suggest <10% potential for thunder. The Elevated area remains unchanged. See previous discussion below for more information. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0133 AM CDT Fri Aug 08 2025/ ...Synopsis... Elevated fire weather conditions and isolated dry thunderstorms are expected across portions of the Four Corners and northern Rockies on Saturday afternoon. The upper trough currently traversing MT is expected to undergo slight de-amplification as it drifts east into the southern Canadian Prairies through late Saturday. As this occurs, both mid-level flow over the Intermountain West and surface pressure gradient winds will weaken, which will modulate the potential for reaching critical wind/RH conditions across the Four Corners region where fuels will remain very dry. However, deep diurnal mixing and lingering 15-25 mph winds within the lowest few kilometers should promote breezy conditions (sustained winds most likely between 15-20 mph) with single-digit to low-teen RH minimums. In addition to elevated fire weather conditions, weak orographic ascent off the Mogollon Rim in AZ/western NM as well as lift ahead of a weak embedded shortwave trough in the northern Rockies will promote areas of isolated thunderstorms. Dry air masses in both regions (PWATs generally less than 0.75 inches) coupled with sufficiently fast storm motions (15-20 knots) should support the potential for dry lightning strikes over receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Fri Aug 08 2025 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF WI/IA/IL AND CO... ...SUMMARY... Multiple damaging wind swaths are possible from Saturday into Saturday night, centered on central/southern Wisconsin, central/eastern Iowa, and northwest Illinois. Multiple rounds of large hail are possible across eastern Colorado starting in the late afternoon. ...Upper Great Lakes to the Lower MO Valley... A broken linear MCS should be ongoing at 12Z Saturday, centered from western Upper MI to northern IA. Some CAMs suggest this should decay into multiple separate clusters during the late morning, while most maintain at least one coherent linear band eastward. Diurnal destabilization ahead of the large-scale outflow may support intensification by midday into the afternoon, mainly in WI. The bulk of strong mid-level southwesterlies will be displaced to the rear of the composite outflow/cold front as the amplified shortwave trough over the northern Great Plains drifts east. This will yield a pronounced gradient from northwest to southeast across the outflow/front, and support decreasing organization as clusters reach the Lake MI vicinity. Scattered damaging winds should be the predominant hazard. A broad low-level jet will nocturnally strengthen from the southern High Plains to the Lower MO Valley. Regenerative storm development is expected in the IA vicinity along the trailing front as it becomes quasi-stationary and orients west/east. With ample buoyancy lingering, modest organization into small-scale bows is possible on Saturday night, yielding another round of damaging wind potential. ...Central/southern High Plains... A cold front pushing south on D1 should become quasi-stationary over the southern High Plains in the TX Panhandle tomorrow. Isolated storms are possible near the boundary with a threat for sporadic microbursts amid hot temperatures south of the front. Farther north along the Front Range, a post-frontal upslope flow regime will favor regenerative supercell development commencing by late afternoon. With modestly enhanced mid-level westerlies atop the weak low-level easterlies, strong deep-layer shear and adequate buoyancy will favor a risk of large to significant severe hail centered on east-central/southeast CO. A low-amplitude shortwave impulse ejecting towards the southern Rockies should foster thunderstorms persisting well into Saturday night. While buoyancy will nocturnally weaken, isolated severe hail/wind may occur from eastern CO into western KS. ..Grams.. 08/08/2025 Read more