Severe Storms

No watches are valid as of Fri Aug 22 19:33:02 UTC 2025.

MD 2004 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN NEBRASKA INTO WESTERN IOWA
Mesoscale Discussion 2004 NWS Storm Prediction Center Norman OK 0231 PM CDT Fri Aug 22 2025 Areas affected...Eastern Nebraska into western Iowa Concerning...Severe potential...Watch unlikely Valid 221931Z - 222130Z Probability of Watch Issuance...5 percent SUMMARY...A strong to severe storm or two may emerge later this afternoon across eastern Nebraska into western Iowa. This threat is expected to remain sufficiently isolated to preclude watch issuance. DISCUSSION...Convection percolating along a weak cold front across northeast NE over the past 1-2 hours has recently shown signs of slow intensification per cooling cloud-top temperatures, increased lightning counts, and increasing vertically integrated ice values. This intensification is most likely attributable to gradual destabilization across eastern NE/western IA where temperatures are climbing into in the low/mid 80s. A modified 18z OAX sounding suggests that this air mass is supporting MLCAPE values around 1000 J/kg MLCAPE, and 25-30 knot flow is noted between 5-7 km AGL. This parameter space is generally supportive of at least loosely organized convection that may pose a severe hail/wind risk through the afternoon. However, poor lapse-rates between 1-5 km are also noted, which given the weak forcing for ascent, may modulate storm intensity and limit convective coverage. Latest CAM guidance also hints that convection may struggle to maintain intensity, which further limits confidence in the overall severe threat. Nonetheless, an isolated severe hail/wind risk may materialize through late afternoon as daytime heating continues to destabilize the immediate downstream environment. ..Moore/Gleason.. 08/22/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...FSD...OAX...GID...LBF... LAT...LON 41009758 41149793 41319821 41629853 41879869 42069868 42199846 42289814 42699695 42939645 43059612 43009576 42609515 42359489 42039487 41739498 41499534 41269586 41079635 41009698 41009758 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 PM CDT Fri Aug 22 2025 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN COLORADO INTO WESTERN KANSAS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across eastern Colorado into western Kansas Sunday afternoon and evening. ...Central High Plains... Northwesterly mid/upper flow will be in place across the High Plains on Sunday on the back side of the large-scale upper trough over the eastern U.S. A midlevel shortwave impulse is forecast to move across the central Rockies during the afternoon/evening. At the same time, southerly low-level flow will maintain a narrow corridor of modest boundary layer moisture (upper 50s to low 60s F) across parts of eastern CO/western KS. Steep midlevel lapse rates will aid in 1000-2000 J/kg MLCAPE values within this corridor. As a result, thunderstorms are likely to develop over higher terrain during the afternoon and could spread southeast into the moist axis. Some uncertainty exists with regards to early-day convection and cloud cover. Afternoon temperatures may remain rather cool and could hamper stronger destabilization. However, if storms can develop and become sustained off the higher terrain, vertical shear will be sufficient for organized cells. Elongated forecast hodographs and cool 500 mb temperatures indicate hail could occur with any stronger sustained cells. If stronger heating/boundary layer mixing can occur, gusty winds also may accompany this activity. ..Leitman.. 08/22/2025 Read more

No Mesoscale Discussions are in effect as of Fri Aug 22 18:46:02 UTC 2025.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0122 PM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...Update... A mix of wet and dry thunderstorms are expected to develop early Saturday afternoon from the southern CA Peninsular Ranges northward over portions of the Great Basin and Sierra. The previous forecast has been adjusted southward to account for higher thunderstorm probabilities within monsoonal moisture and over the more receptive fuels within the Great Basin. Isolated strikes can't be completely ruled out within the previously forecast region over southern/central OR, but new NWP data suggests thunderstorm coverage will remain too low for a continuation of this area. An additional, small area of Isolated Dry Thunderstorms was also included for the southern mountains of CA where ERC percentiles will remain above the 97th percentile tomorrow. Please see the previous discussion for additional details. ..Barnes.. 08/22/2025 .PREV DISCUSSION... /ISSUED 0202 AM CDT Fri Aug 22 2025/ ...Synopsis... An amplified large-scale ridge will continue over the western CONUS on Day 2/Saturday. ...Dry Thunderstorms... Along the western periphery of the ridge, monsoonal moisture will continue spreading northward from the Sierra into the Northwest. Sufficient buoyancy will support isolated mostly dry thunderstorms during the afternoon/early evening time frame. Given dry/receptive fuels, isolated lightning-induced ignitions will be possible. Farther south, isolated thunderstorms are also expected across parts of southern CA into the Great Basin. However, deep monsoonal moisture will promote mixed wet/dry thunderstorms. Nevertheless, lightning-induced ignitions will be possible away from any heavier rain cores, along with gusty/erratic outflow winds. ...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 0122 PM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...Update... A mix of wet and dry thunderstorms are expected to develop early Saturday afternoon from the southern CA Peninsular Ranges northward over portions of the Great Basin and Sierra. The previous forecast has been adjusted southward to account for higher thunderstorm probabilities within monsoonal moisture and over the more receptive fuels within the Great Basin. Isolated strikes can't be completely ruled out within the previously forecast region over southern/central OR, but new NWP data suggests thunderstorm coverage will remain too low for a continuation of this area. An additional, small area of Isolated Dry Thunderstorms was also included for the southern mountains of CA where ERC percentiles will remain above the 97th percentile tomorrow. Please see the previous discussion for additional details. ..Barnes.. 08/22/2025 .PREV DISCUSSION... /ISSUED 0202 AM CDT Fri Aug 22 2025/ ...Synopsis... An amplified large-scale ridge will continue over the western CONUS on Day 2/Saturday. ...Dry Thunderstorms... Along the western periphery of the ridge, monsoonal moisture will continue spreading northward from the Sierra into the Northwest. Sufficient buoyancy will support isolated mostly dry thunderstorms during the afternoon/early evening time frame. Given dry/receptive fuels, isolated lightning-induced ignitions will be possible. Farther south, isolated thunderstorms are also expected across parts of southern CA into the Great Basin. However, deep monsoonal moisture will promote mixed wet/dry thunderstorms. Nevertheless, lightning-induced ignitions will be possible away from any heavier rain cores, along with gusty/erratic outflow winds. ...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 0122 PM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...Update... A mix of wet and dry thunderstorms are expected to develop early Saturday afternoon from the southern CA Peninsular Ranges northward over portions of the Great Basin and Sierra. The previous forecast has been adjusted southward to account for higher thunderstorm probabilities within monsoonal moisture and over the more receptive fuels within the Great Basin. Isolated strikes can't be completely ruled out within the previously forecast region over southern/central OR, but new NWP data suggests thunderstorm coverage will remain too low for a continuation of this area. An additional, small area of Isolated Dry Thunderstorms was also included for the southern mountains of CA where ERC percentiles will remain above the 97th percentile tomorrow. Please see the previous discussion for additional details. ..Barnes.. 08/22/2025 .PREV DISCUSSION... /ISSUED 0202 AM CDT Fri Aug 22 2025/ ...Synopsis... An amplified large-scale ridge will continue over the western CONUS on Day 2/Saturday. ...Dry Thunderstorms... Along the western periphery of the ridge, monsoonal moisture will continue spreading northward from the Sierra into the Northwest. Sufficient buoyancy will support isolated mostly dry thunderstorms during the afternoon/early evening time frame. Given dry/receptive fuels, isolated lightning-induced ignitions will be possible. Farther south, isolated thunderstorms are also expected across parts of southern CA into the Great Basin. However, deep monsoonal moisture will promote mixed wet/dry thunderstorms. Nevertheless, lightning-induced ignitions will be possible away from any heavier rain cores, along with gusty/erratic outflow winds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2003 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR EASTERN MINNESOTA INTO NORTHERN WISCONSIN AND THE WESTERN UPPER PENINSULA OF MICHIGAN
Mesoscale Discussion 2003 NWS Storm Prediction Center Norman OK 1152 AM CDT Fri Aug 22 2025 Areas affected...Far eastern Minnesota into northern Wisconsin and the western Upper Peninsula of Michigan Concerning...Severe potential...Watch unlikely Valid 221652Z - 221845Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorm clusters developing across northern Wisconsin may pose a localized severe hail/wind risk through the afternoon as they spread east into the Upper Peninsula of Michigan. Watch issuance is currently not anticipated, but trends will be monitored. DISCUSSION...Thunderstorms developing along a surface cold front across far eastern MN and northwest WI have shown signs of gradual intensification per MRMS and GOES IR imagery. While stronger mid/upper-level flow will likely remain displaced to the north/northwest, recent VWP observations from KDLH sampled 0-6 km BWD values on the order of 25-30 knots. This may promote some degree of organization of embedded cells within the larger cluster through early afternoon and cold pool consolidation/organization by mid/late afternoon. Muted daytime heating of a seasonably moist air mass in place downstream ahead of the front should promote a modest increase in MLCAPE to around 1500 J/kg by mid-afternoon, which may also bolster convective intensity to some degree. In general, the expectation is that this activity will pose a threat for isolated hail and perhaps isolated to scattered damaging/severe gusts. There is some potential that a more widespread damaging wind threat could emerge if convective intensity/organization is more substantial than currently anticipated as hinted by a few morning CAM solutions. This scenario could warrant a targeted watch issuance later this afternoon, but based on current observations (ongoing cloud cover, delayed surface heating, etc...), this potential seems low. ..Moore/Gleason.. 08/22/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MQT...GRB...DLH...MPX... LAT...LON 46928988 47008938 46948915 46738878 46368856 45978854 45638862 45478902 45369271 45519319 45709343 46039340 46339293 46509196 46669115 46928988 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms is low across the continental U.S. for Saturday. ...Synopsis... An upper trough will deepen over the Great Lakes and Midwest, enveloping much of the eastern half of the U.S. on Saturday. Meanwhile, an amplified upper ridge will persist across the West. At the surface, a cold front will extend from Upper MI into northeast NM Saturday morning, and sweep east/southeast through the period across much of the MS/OH Valleys into the southern Plains. A seasonally moist airmass ahead of the front will result in a narrow corridor of modest destabilization across Lower MI into the Mid-MS Valley, and westward across parts of KS/OK and the central/southern High Plains. Isolated to widely scattered thunderstorms may develop near the cold front, or in the post-frontal upslope regime across the central High Plains. Modest midlevel lapse rates are forecast amid MLCAPE around 1000 J/kg. Poor convergence along the front and weak large-scale ascent with south and westward extent should limit storm coverage. Overall, severe potential appears low. ..Leitman.. 08/22/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms is low across the continental U.S. for Saturday. ...Synopsis... An upper trough will deepen over the Great Lakes and Midwest, enveloping much of the eastern half of the U.S. on Saturday. Meanwhile, an amplified upper ridge will persist across the West. At the surface, a cold front will extend from Upper MI into northeast NM Saturday morning, and sweep east/southeast through the period across much of the MS/OH Valleys into the southern Plains. A seasonally moist airmass ahead of the front will result in a narrow corridor of modest destabilization across Lower MI into the Mid-MS Valley, and westward across parts of KS/OK and the central/southern High Plains. Isolated to widely scattered thunderstorms may develop near the cold front, or in the post-frontal upslope regime across the central High Plains. Modest midlevel lapse rates are forecast amid MLCAPE around 1000 J/kg. Poor convergence along the front and weak large-scale ascent with south and westward extent should limit storm coverage. Overall, severe potential appears low. ..Leitman.. 08/22/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms is low across the continental U.S. for Saturday. ...Synopsis... An upper trough will deepen over the Great Lakes and Midwest, enveloping much of the eastern half of the U.S. on Saturday. Meanwhile, an amplified upper ridge will persist across the West. At the surface, a cold front will extend from Upper MI into northeast NM Saturday morning, and sweep east/southeast through the period across much of the MS/OH Valleys into the southern Plains. A seasonally moist airmass ahead of the front will result in a narrow corridor of modest destabilization across Lower MI into the Mid-MS Valley, and westward across parts of KS/OK and the central/southern High Plains. Isolated to widely scattered thunderstorms may develop near the cold front, or in the post-frontal upslope regime across the central High Plains. Modest midlevel lapse rates are forecast amid MLCAPE around 1000 J/kg. Poor convergence along the front and weak large-scale ascent with south and westward extent should limit storm coverage. Overall, severe potential appears low. ..Leitman.. 08/22/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms is low across the continental U.S. for Saturday. ...Synopsis... An upper trough will deepen over the Great Lakes and Midwest, enveloping much of the eastern half of the U.S. on Saturday. Meanwhile, an amplified upper ridge will persist across the West. At the surface, a cold front will extend from Upper MI into northeast NM Saturday morning, and sweep east/southeast through the period across much of the MS/OH Valleys into the southern Plains. A seasonally moist airmass ahead of the front will result in a narrow corridor of modest destabilization across Lower MI into the Mid-MS Valley, and westward across parts of KS/OK and the central/southern High Plains. Isolated to widely scattered thunderstorms may develop near the cold front, or in the post-frontal upslope regime across the central High Plains. Modest midlevel lapse rates are forecast amid MLCAPE around 1000 J/kg. Poor convergence along the front and weak large-scale ascent with south and westward extent should limit storm coverage. Overall, severe potential appears low. ..Leitman.. 08/22/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms is low across the continental U.S. for Saturday. ...Synopsis... An upper trough will deepen over the Great Lakes and Midwest, enveloping much of the eastern half of the U.S. on Saturday. Meanwhile, an amplified upper ridge will persist across the West. At the surface, a cold front will extend from Upper MI into northeast NM Saturday morning, and sweep east/southeast through the period across much of the MS/OH Valleys into the southern Plains. A seasonally moist airmass ahead of the front will result in a narrow corridor of modest destabilization across Lower MI into the Mid-MS Valley, and westward across parts of KS/OK and the central/southern High Plains. Isolated to widely scattered thunderstorms may develop near the cold front, or in the post-frontal upslope regime across the central High Plains. Modest midlevel lapse rates are forecast amid MLCAPE around 1000 J/kg. Poor convergence along the front and weak large-scale ascent with south and westward extent should limit storm coverage. Overall, severe potential appears low. ..Leitman.. 08/22/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1132 AM CDT Fri Aug 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms is low across the continental U.S. for Saturday. ...Synopsis... An upper trough will deepen over the Great Lakes and Midwest, enveloping much of the eastern half of the U.S. on Saturday. Meanwhile, an amplified upper ridge will persist across the West. At the surface, a cold front will extend from Upper MI into northeast NM Saturday morning, and sweep east/southeast through the period across much of the MS/OH Valleys into the southern Plains. A seasonally moist airmass ahead of the front will result in a narrow corridor of modest destabilization across Lower MI into the Mid-MS Valley, and westward across parts of KS/OK and the central/southern High Plains. Isolated to widely scattered thunderstorms may develop near the cold front, or in the post-frontal upslope regime across the central High Plains. Modest midlevel lapse rates are forecast amid MLCAPE around 1000 J/kg. Poor convergence along the front and weak large-scale ascent with south and westward extent should limit storm coverage. Overall, severe potential appears low. ..Leitman.. 08/22/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Aug 22 2025 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA... ...SUMMARY... Strong to locally severe thunderstorms may occur today from parts of the northern and central High Plains to the Upper Midwest/Great Lakes, and separately across parts of Arizona. Damaging winds and occasional hail should be the main threats. ...Synopsis... A mid/upper-level trough/low centered over Manitoba late this morning will move east-southeastward across Ontario and the Upper Midwest/Great Lakes through the period. At the surface, a weak cold front is forecast to develop southeastward across the northern/central High Plains and Upper Midwest this afternoon and evening. This boundary should serve as a focus for additional thunderstorm development later today, some of which could become strong to severe. A mid/upper-level anticyclone will remain anchored over the Four Corners region today, with modest easterly mid-level flow persisting over parts of AZ. ...Northern/Central High Plains to the Upper Midwest/Great Lakes... A broad zone of isolated strong to severe thunderstorm potential remains evident today, generally along/near a convectively reinforced cold front extending from the central High Plains east-northeastward to the Upper Midwest/Great Lakes. Within this broad zone, three somewhat separate regimes of severe potential are apparent. Thunderstorms have recently developed across parts of central/eastern MN and far northwest WI ahead of a remnant MCV/subtle mid-level shortwave trough. The airmass downstream from this activity across northern WI into the U.P. of MI is only weakly unstable, with scattered to broken mid/upper-level clouds present. Stronger mid-level flow is also forecast to generally lag behind the surface cold front across this region. Still, a small cluster or two may eventually evolve from the ongoing convection in MN, and spread eastward through the afternoon/early evening. Occasional damaging winds should be the main threat, but some hail may also occur with the stronger cores given cool mid-level temperatures and around 25-35 kt of deep-layer shear aiding updraft organization. Considered adding a Slight Risk for severe/damaging winds across parts of northern WI and vicinity, but confidence in more robust destabilization occurring remains low. Trends will be monitored for a possible upgrade at 20Z, if needed. Outflow from earlier thunderstorms continues to advance southward across parts of eastern NE and northwest IA per recent surface observations and visible satellite imagery. The effect of this outflow surge on additional thunderstorm development this afternoon remains unclear, as the primary cold front lags the outflow by a considerable extent. Some guidance suggests that a couple of supercells or perhaps a small cluster may develop over far southeast SD into eastern NE and western IA later today as the airmass across these areas gradually destabilizes. At least an isolated risk for severe hail and damaging winds will exist if this occurs. But, the overall severe threat remains too uncertain for a categorical upgrade with this outlook update. Farther west, a subtle mid-level ridge-peripheral disturbance noted in water vapor imagery across southern WY and northwest CO, along with strong daytime heating, should aid thunderstorm development initially across the higher terrain of the central Rockies later this afternoon. This activity should propagate east-southeastward toward lower elevations in the presence of moist, post-frontal low-level upslope flow. Isolated severe hail and winds are possible with this activity, especially within a corridor across interior/southeast WY into northeast/east-central CO. ...Arizona... A fair amount of convective cloud debris is present today across parts of AZ per recent visible satellite imagery. This may tend to delay diurnal heating and related steepening of low-level lapse rates to some extent. But, eventual airmass recovery is still expected by late afternoon/early evening, with seasonably moist low-levels still noted on the 12Z observed PHX sounding. Thunderstorms should once again form initially along the higher terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern AZ through the evening. Sufficient instability, a very well-mixed boundary layer, and modest easterly mid-level flow should all support an isolated threat for severe/damaging winds with this activity. ..Gleason/Moore.. 08/22/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Aug 22 2025 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA... ...SUMMARY... Strong to locally severe thunderstorms may occur today from parts of the northern and central High Plains to the Upper Midwest/Great Lakes, and separately across parts of Arizona. Damaging winds and occasional hail should be the main threats. ...Synopsis... A mid/upper-level trough/low centered over Manitoba late this morning will move east-southeastward across Ontario and the Upper Midwest/Great Lakes through the period. At the surface, a weak cold front is forecast to develop southeastward across the northern/central High Plains and Upper Midwest this afternoon and evening. This boundary should serve as a focus for additional thunderstorm development later today, some of which could become strong to severe. A mid/upper-level anticyclone will remain anchored over the Four Corners region today, with modest easterly mid-level flow persisting over parts of AZ. ...Northern/Central High Plains to the Upper Midwest/Great Lakes... A broad zone of isolated strong to severe thunderstorm potential remains evident today, generally along/near a convectively reinforced cold front extending from the central High Plains east-northeastward to the Upper Midwest/Great Lakes. Within this broad zone, three somewhat separate regimes of severe potential are apparent. Thunderstorms have recently developed across parts of central/eastern MN and far northwest WI ahead of a remnant MCV/subtle mid-level shortwave trough. The airmass downstream from this activity across northern WI into the U.P. of MI is only weakly unstable, with scattered to broken mid/upper-level clouds present. Stronger mid-level flow is also forecast to generally lag behind the surface cold front across this region. Still, a small cluster or two may eventually evolve from the ongoing convection in MN, and spread eastward through the afternoon/early evening. Occasional damaging winds should be the main threat, but some hail may also occur with the stronger cores given cool mid-level temperatures and around 25-35 kt of deep-layer shear aiding updraft organization. Considered adding a Slight Risk for severe/damaging winds across parts of northern WI and vicinity, but confidence in more robust destabilization occurring remains low. Trends will be monitored for a possible upgrade at 20Z, if needed. Outflow from earlier thunderstorms continues to advance southward across parts of eastern NE and northwest IA per recent surface observations and visible satellite imagery. The effect of this outflow surge on additional thunderstorm development this afternoon remains unclear, as the primary cold front lags the outflow by a considerable extent. Some guidance suggests that a couple of supercells or perhaps a small cluster may develop over far southeast SD into eastern NE and western IA later today as the airmass across these areas gradually destabilizes. At least an isolated risk for severe hail and damaging winds will exist if this occurs. But, the overall severe threat remains too uncertain for a categorical upgrade with this outlook update. Farther west, a subtle mid-level ridge-peripheral disturbance noted in water vapor imagery across southern WY and northwest CO, along with strong daytime heating, should aid thunderstorm development initially across the higher terrain of the central Rockies later this afternoon. This activity should propagate east-southeastward toward lower elevations in the presence of moist, post-frontal low-level upslope flow. Isolated severe hail and winds are possible with this activity, especially within a corridor across interior/southeast WY into northeast/east-central CO. ...Arizona... A fair amount of convective cloud debris is present today across parts of AZ per recent visible satellite imagery. This may tend to delay diurnal heating and related steepening of low-level lapse rates to some extent. But, eventual airmass recovery is still expected by late afternoon/early evening, with seasonably moist low-levels still noted on the 12Z observed PHX sounding. Thunderstorms should once again form initially along the higher terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern AZ through the evening. Sufficient instability, a very well-mixed boundary layer, and modest easterly mid-level flow should all support an isolated threat for severe/damaging winds with this activity. ..Gleason/Moore.. 08/22/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Aug 22 2025 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA... ...SUMMARY... Strong to locally severe thunderstorms may occur today from parts of the northern and central High Plains to the Upper Midwest/Great Lakes, and separately across parts of Arizona. Damaging winds and occasional hail should be the main threats. ...Synopsis... A mid/upper-level trough/low centered over Manitoba late this morning will move east-southeastward across Ontario and the Upper Midwest/Great Lakes through the period. At the surface, a weak cold front is forecast to develop southeastward across the northern/central High Plains and Upper Midwest this afternoon and evening. This boundary should serve as a focus for additional thunderstorm development later today, some of which could become strong to severe. A mid/upper-level anticyclone will remain anchored over the Four Corners region today, with modest easterly mid-level flow persisting over parts of AZ. ...Northern/Central High Plains to the Upper Midwest/Great Lakes... A broad zone of isolated strong to severe thunderstorm potential remains evident today, generally along/near a convectively reinforced cold front extending from the central High Plains east-northeastward to the Upper Midwest/Great Lakes. Within this broad zone, three somewhat separate regimes of severe potential are apparent. Thunderstorms have recently developed across parts of central/eastern MN and far northwest WI ahead of a remnant MCV/subtle mid-level shortwave trough. The airmass downstream from this activity across northern WI into the U.P. of MI is only weakly unstable, with scattered to broken mid/upper-level clouds present. Stronger mid-level flow is also forecast to generally lag behind the surface cold front across this region. Still, a small cluster or two may eventually evolve from the ongoing convection in MN, and spread eastward through the afternoon/early evening. Occasional damaging winds should be the main threat, but some hail may also occur with the stronger cores given cool mid-level temperatures and around 25-35 kt of deep-layer shear aiding updraft organization. Considered adding a Slight Risk for severe/damaging winds across parts of northern WI and vicinity, but confidence in more robust destabilization occurring remains low. Trends will be monitored for a possible upgrade at 20Z, if needed. Outflow from earlier thunderstorms continues to advance southward across parts of eastern NE and northwest IA per recent surface observations and visible satellite imagery. The effect of this outflow surge on additional thunderstorm development this afternoon remains unclear, as the primary cold front lags the outflow by a considerable extent. Some guidance suggests that a couple of supercells or perhaps a small cluster may develop over far southeast SD into eastern NE and western IA later today as the airmass across these areas gradually destabilizes. At least an isolated risk for severe hail and damaging winds will exist if this occurs. But, the overall severe threat remains too uncertain for a categorical upgrade with this outlook update. Farther west, a subtle mid-level ridge-peripheral disturbance noted in water vapor imagery across southern WY and northwest CO, along with strong daytime heating, should aid thunderstorm development initially across the higher terrain of the central Rockies later this afternoon. This activity should propagate east-southeastward toward lower elevations in the presence of moist, post-frontal low-level upslope flow. Isolated severe hail and winds are possible with this activity, especially within a corridor across interior/southeast WY into northeast/east-central CO. ...Arizona... A fair amount of convective cloud debris is present today across parts of AZ per recent visible satellite imagery. This may tend to delay diurnal heating and related steepening of low-level lapse rates to some extent. But, eventual airmass recovery is still expected by late afternoon/early evening, with seasonably moist low-levels still noted on the 12Z observed PHX sounding. Thunderstorms should once again form initially along the higher terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern AZ through the evening. Sufficient instability, a very well-mixed boundary layer, and modest easterly mid-level flow should all support an isolated threat for severe/damaging winds with this activity. ..Gleason/Moore.. 08/22/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Aug 22 2025 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA... ...SUMMARY... Strong to locally severe thunderstorms may occur today from parts of the northern and central High Plains to the Upper Midwest/Great Lakes, and separately across parts of Arizona. Damaging winds and occasional hail should be the main threats. ...Synopsis... A mid/upper-level trough/low centered over Manitoba late this morning will move east-southeastward across Ontario and the Upper Midwest/Great Lakes through the period. At the surface, a weak cold front is forecast to develop southeastward across the northern/central High Plains and Upper Midwest this afternoon and evening. This boundary should serve as a focus for additional thunderstorm development later today, some of which could become strong to severe. A mid/upper-level anticyclone will remain anchored over the Four Corners region today, with modest easterly mid-level flow persisting over parts of AZ. ...Northern/Central High Plains to the Upper Midwest/Great Lakes... A broad zone of isolated strong to severe thunderstorm potential remains evident today, generally along/near a convectively reinforced cold front extending from the central High Plains east-northeastward to the Upper Midwest/Great Lakes. Within this broad zone, three somewhat separate regimes of severe potential are apparent. Thunderstorms have recently developed across parts of central/eastern MN and far northwest WI ahead of a remnant MCV/subtle mid-level shortwave trough. The airmass downstream from this activity across northern WI into the U.P. of MI is only weakly unstable, with scattered to broken mid/upper-level clouds present. Stronger mid-level flow is also forecast to generally lag behind the surface cold front across this region. Still, a small cluster or two may eventually evolve from the ongoing convection in MN, and spread eastward through the afternoon/early evening. Occasional damaging winds should be the main threat, but some hail may also occur with the stronger cores given cool mid-level temperatures and around 25-35 kt of deep-layer shear aiding updraft organization. Considered adding a Slight Risk for severe/damaging winds across parts of northern WI and vicinity, but confidence in more robust destabilization occurring remains low. Trends will be monitored for a possible upgrade at 20Z, if needed. Outflow from earlier thunderstorms continues to advance southward across parts of eastern NE and northwest IA per recent surface observations and visible satellite imagery. The effect of this outflow surge on additional thunderstorm development this afternoon remains unclear, as the primary cold front lags the outflow by a considerable extent. Some guidance suggests that a couple of supercells or perhaps a small cluster may develop over far southeast SD into eastern NE and western IA later today as the airmass across these areas gradually destabilizes. At least an isolated risk for severe hail and damaging winds will exist if this occurs. But, the overall severe threat remains too uncertain for a categorical upgrade with this outlook update. Farther west, a subtle mid-level ridge-peripheral disturbance noted in water vapor imagery across southern WY and northwest CO, along with strong daytime heating, should aid thunderstorm development initially across the higher terrain of the central Rockies later this afternoon. This activity should propagate east-southeastward toward lower elevations in the presence of moist, post-frontal low-level upslope flow. Isolated severe hail and winds are possible with this activity, especially within a corridor across interior/southeast WY into northeast/east-central CO. ...Arizona... A fair amount of convective cloud debris is present today across parts of AZ per recent visible satellite imagery. This may tend to delay diurnal heating and related steepening of low-level lapse rates to some extent. But, eventual airmass recovery is still expected by late afternoon/early evening, with seasonably moist low-levels still noted on the 12Z observed PHX sounding. Thunderstorms should once again form initially along the higher terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern AZ through the evening. Sufficient instability, a very well-mixed boundary layer, and modest easterly mid-level flow should all support an isolated threat for severe/damaging winds with this activity. ..Gleason/Moore.. 08/22/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Aug 22 2025 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA... ...SUMMARY... Strong to locally severe thunderstorms may occur today from parts of the northern and central High Plains to the Upper Midwest/Great Lakes, and separately across parts of Arizona. Damaging winds and occasional hail should be the main threats. ...Synopsis... A mid/upper-level trough/low centered over Manitoba late this morning will move east-southeastward across Ontario and the Upper Midwest/Great Lakes through the period. At the surface, a weak cold front is forecast to develop southeastward across the northern/central High Plains and Upper Midwest this afternoon and evening. This boundary should serve as a focus for additional thunderstorm development later today, some of which could become strong to severe. A mid/upper-level anticyclone will remain anchored over the Four Corners region today, with modest easterly mid-level flow persisting over parts of AZ. ...Northern/Central High Plains to the Upper Midwest/Great Lakes... A broad zone of isolated strong to severe thunderstorm potential remains evident today, generally along/near a convectively reinforced cold front extending from the central High Plains east-northeastward to the Upper Midwest/Great Lakes. Within this broad zone, three somewhat separate regimes of severe potential are apparent. Thunderstorms have recently developed across parts of central/eastern MN and far northwest WI ahead of a remnant MCV/subtle mid-level shortwave trough. The airmass downstream from this activity across northern WI into the U.P. of MI is only weakly unstable, with scattered to broken mid/upper-level clouds present. Stronger mid-level flow is also forecast to generally lag behind the surface cold front across this region. Still, a small cluster or two may eventually evolve from the ongoing convection in MN, and spread eastward through the afternoon/early evening. Occasional damaging winds should be the main threat, but some hail may also occur with the stronger cores given cool mid-level temperatures and around 25-35 kt of deep-layer shear aiding updraft organization. Considered adding a Slight Risk for severe/damaging winds across parts of northern WI and vicinity, but confidence in more robust destabilization occurring remains low. Trends will be monitored for a possible upgrade at 20Z, if needed. Outflow from earlier thunderstorms continues to advance southward across parts of eastern NE and northwest IA per recent surface observations and visible satellite imagery. The effect of this outflow surge on additional thunderstorm development this afternoon remains unclear, as the primary cold front lags the outflow by a considerable extent. Some guidance suggests that a couple of supercells or perhaps a small cluster may develop over far southeast SD into eastern NE and western IA later today as the airmass across these areas gradually destabilizes. At least an isolated risk for severe hail and damaging winds will exist if this occurs. But, the overall severe threat remains too uncertain for a categorical upgrade with this outlook update. Farther west, a subtle mid-level ridge-peripheral disturbance noted in water vapor imagery across southern WY and northwest CO, along with strong daytime heating, should aid thunderstorm development initially across the higher terrain of the central Rockies later this afternoon. This activity should propagate east-southeastward toward lower elevations in the presence of moist, post-frontal low-level upslope flow. Isolated severe hail and winds are possible with this activity, especially within a corridor across interior/southeast WY into northeast/east-central CO. ...Arizona... A fair amount of convective cloud debris is present today across parts of AZ per recent visible satellite imagery. This may tend to delay diurnal heating and related steepening of low-level lapse rates to some extent. But, eventual airmass recovery is still expected by late afternoon/early evening, with seasonably moist low-levels still noted on the 12Z observed PHX sounding. Thunderstorms should once again form initially along the higher terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern AZ through the evening. Sufficient instability, a very well-mixed boundary layer, and modest easterly mid-level flow should all support an isolated threat for severe/damaging winds with this activity. ..Gleason/Moore.. 08/22/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Aug 22 2025 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS TO THE UPPER MIDWEST/GREAT LAKES...AND PORTIONS OF SOUTHERN/CENTRAL ARIZONA... ...SUMMARY... Strong to locally severe thunderstorms may occur today from parts of the northern and central High Plains to the Upper Midwest/Great Lakes, and separately across parts of Arizona. Damaging winds and occasional hail should be the main threats. ...Synopsis... A mid/upper-level trough/low centered over Manitoba late this morning will move east-southeastward across Ontario and the Upper Midwest/Great Lakes through the period. At the surface, a weak cold front is forecast to develop southeastward across the northern/central High Plains and Upper Midwest this afternoon and evening. This boundary should serve as a focus for additional thunderstorm development later today, some of which could become strong to severe. A mid/upper-level anticyclone will remain anchored over the Four Corners region today, with modest easterly mid-level flow persisting over parts of AZ. ...Northern/Central High Plains to the Upper Midwest/Great Lakes... A broad zone of isolated strong to severe thunderstorm potential remains evident today, generally along/near a convectively reinforced cold front extending from the central High Plains east-northeastward to the Upper Midwest/Great Lakes. Within this broad zone, three somewhat separate regimes of severe potential are apparent. Thunderstorms have recently developed across parts of central/eastern MN and far northwest WI ahead of a remnant MCV/subtle mid-level shortwave trough. The airmass downstream from this activity across northern WI into the U.P. of MI is only weakly unstable, with scattered to broken mid/upper-level clouds present. Stronger mid-level flow is also forecast to generally lag behind the surface cold front across this region. Still, a small cluster or two may eventually evolve from the ongoing convection in MN, and spread eastward through the afternoon/early evening. Occasional damaging winds should be the main threat, but some hail may also occur with the stronger cores given cool mid-level temperatures and around 25-35 kt of deep-layer shear aiding updraft organization. Considered adding a Slight Risk for severe/damaging winds across parts of northern WI and vicinity, but confidence in more robust destabilization occurring remains low. Trends will be monitored for a possible upgrade at 20Z, if needed. Outflow from earlier thunderstorms continues to advance southward across parts of eastern NE and northwest IA per recent surface observations and visible satellite imagery. The effect of this outflow surge on additional thunderstorm development this afternoon remains unclear, as the primary cold front lags the outflow by a considerable extent. Some guidance suggests that a couple of supercells or perhaps a small cluster may develop over far southeast SD into eastern NE and western IA later today as the airmass across these areas gradually destabilizes. At least an isolated risk for severe hail and damaging winds will exist if this occurs. But, the overall severe threat remains too uncertain for a categorical upgrade with this outlook update. Farther west, a subtle mid-level ridge-peripheral disturbance noted in water vapor imagery across southern WY and northwest CO, along with strong daytime heating, should aid thunderstorm development initially across the higher terrain of the central Rockies later this afternoon. This activity should propagate east-southeastward toward lower elevations in the presence of moist, post-frontal low-level upslope flow. Isolated severe hail and winds are possible with this activity, especially within a corridor across interior/southeast WY into northeast/east-central CO. ...Arizona... A fair amount of convective cloud debris is present today across parts of AZ per recent visible satellite imagery. This may tend to delay diurnal heating and related steepening of low-level lapse rates to some extent. But, eventual airmass recovery is still expected by late afternoon/early evening, with seasonably moist low-levels still noted on the 12Z observed PHX sounding. Thunderstorms should once again form initially along the higher terrain of the Mogollon Rim and southeastern AZ before spreading west-southwestward across the lower elevations of central/southern AZ through the evening. Sufficient instability, a very well-mixed boundary layer, and modest easterly mid-level flow should all support an isolated threat for severe/damaging winds with this activity. ..Gleason/Moore.. 08/22/2025 Read more