Severe Storms

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

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

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

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

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

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

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

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Fri Aug 08 2025 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE FOUR CORNERS INTO SOUTHERN WYOMING... Minor adjustments were made to reduce isolated dry thunderstorm coverage across eastern Arizona and in central Colorado. This change is in agreement with recent trends in HREF guidance, with a decrease in signal (<10%) for thunderstorms across these regions. Otherwise, the Elevated and Critical delineations remain unchanged. See previous discussion below for more info. ..Thornton.. 08/08/2025 .PREV DISCUSSION... /ISSUED 0132 AM CDT Fri Aug 08 2025/ ...Synopsis... Critical fire weather conditions are expected from northern Arizona into eastern UT, western CO, and southern WY this afternoon. Early-morning surface observations show southwesterly flow advecting hot/dry air out of the Mohave Desert and into the eastern Great Basin/Four Corners region. This will support another day of sub-10% RH minimums from northern AZ into UT and western CO. Aloft, the passage of a mid-level trough axis will support strengthening flow over the Intermountain West as well as lee troughing across the central High Plains. The result will be bolstered low-level flow across the Four Corners/central Rockies with most guidance suggesting that sustained winds between 20-25 mph are likely. Deep mixing through peak heating will promote frequent wind gusts between 30-45 mph, especially across south-central to eastern UT where ensemble guidance shows the strongest wind signal. Recent reports of active ongoing fires across UT/CO confirm that receptive fuels are in place and will support the Critical fire weather threat. ...Dry Thunderstorms... Lift ahead of the passing trough axis will impinge on the northeastern fringe of a modest plume of recycled monsoonal moisture and support isolated thunderstorm development by late afternoon from eastern AZ to southern CO. 00z RAOBs from across the Southwest sampled steep mid-level lapse rates, deep/dry boundary layers, and PWAT values on the order of 0.5 to 0.8 inches, which are all favorable for dry thunderstorms. While storm coverage is expected to be sparse, thunderstorms that do develop may pose a dry lightning threat over a region with 10-hour fuel moisture near 10% and ongoing moderate to severe drought. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 AM CDT Fri Aug 08 2025 Valid 081630Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT OVER PARTS THE UPPER MIDWEST.... ...SUMMARY... Scattered severe thunderstorms are possible this evening and tonight across parts of the Upper Midwest. Scattered damaging winds, large hail, and a couple tornadoes are possible. ...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. ..Hart/Squitieri.. 08/08/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 AM CDT Fri Aug 08 2025 Valid 081630Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT OVER PARTS THE UPPER MIDWEST.... ...SUMMARY... Scattered severe thunderstorms are possible this evening and tonight across parts of the Upper Midwest. Scattered damaging winds, large hail, and a couple tornadoes are possible. ...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. ..Hart/Squitieri.. 08/08/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 AM CDT Fri Aug 08 2025 Valid 081630Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT OVER PARTS THE UPPER MIDWEST.... ...SUMMARY... Scattered severe thunderstorms are possible this evening and tonight across parts of the Upper Midwest. Scattered damaging winds, large hail, and a couple tornadoes are possible. ...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. ..Hart/Squitieri.. 08/08/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1118 AM CDT Fri Aug 08 2025 Valid 081630Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT OVER PARTS THE UPPER MIDWEST.... ...SUMMARY... Scattered severe thunderstorms are possible this evening and tonight across parts of the Upper Midwest. Scattered damaging winds, large hail, and a couple tornadoes are possible. ...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. ..Hart/Squitieri.. 08/08/2025 Read more