Severe Storms

No watches are valid as of Thu Aug 28 02:15:02 UTC 2025.

No Mesoscale Discussions are in effect as of Thu Aug 28 02:15:02 UTC 2025.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 PM CDT Wed Aug 27 2025 Valid 280100Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms remain possible across parts of the central High Plains early this evening. ...01z Update... Scattered convection persists across much of the western United States early this evening, primarily driven by strong boundary-layer heating. Much of this activity will gradually weaken as the evening progresses. A corridor of modest instability persists across the central High Plains and a few small clusters are noted across eastern Colorado into southwest Kansas. Weak low-level warm advection will maintain this activity into the mid-evening hours, with some upscale growth possible downstream later tonight as LLJ strengthens. Even so, most of this convection should remain sub-severe. ..Darrow.. 08/28/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 PM CDT Wed Aug 27 2025 Valid 280100Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms remain possible across parts of the central High Plains early this evening. ...01z Update... Scattered convection persists across much of the western United States early this evening, primarily driven by strong boundary-layer heating. Much of this activity will gradually weaken as the evening progresses. A corridor of modest instability persists across the central High Plains and a few small clusters are noted across eastern Colorado into southwest Kansas. Weak low-level warm advection will maintain this activity into the mid-evening hours, with some upscale growth possible downstream later tonight as LLJ strengthens. Even so, most of this convection should remain sub-severe. ..Darrow.. 08/28/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 PM CDT Wed Aug 27 2025 Valid 280100Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms remain possible across parts of the central High Plains early this evening. ...01z Update... Scattered convection persists across much of the western United States early this evening, primarily driven by strong boundary-layer heating. Much of this activity will gradually weaken as the evening progresses. A corridor of modest instability persists across the central High Plains and a few small clusters are noted across eastern Colorado into southwest Kansas. Weak low-level warm advection will maintain this activity into the mid-evening hours, with some upscale growth possible downstream later tonight as LLJ strengthens. Even so, most of this convection should remain sub-severe. ..Darrow.. 08/28/2025 Read more

No watches are valid as of Wed Aug 27 22:16:02 UTC 2025.

No Mesoscale Discussions are in effect as of Wed Aug 27 22:16:02 UTC 2025.

MD 2016 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF EASTERN CO INTO WESTERN KS AND A SMALL PART OF THE NE PANHANDLE
Mesoscale Discussion 2016 NWS Storm Prediction Center Norman OK 0313 PM CDT Wed Aug 27 2025 Areas affected...Parts of eastern CO into western KS and a small part of the NE Panhandle Concerning...Severe potential...Watch unlikely Valid 272013Z - 272215Z Probability of Watch Issuance...20 percent SUMMARY...Strong to locally severe storms are possible later this afternoon into this evening. DISCUSSION...Clearing in the wake of earlier mid/high-level cloudiness has allowed for modest diurnal heating from eastern CO into west-central/southwest KS. Temperatures aloft are relatively warm, but boundary-layer warming and sufficient low-level moisture are supporting MLCAPE of near/above 1000 J/kg, with locally greater values across southwest KS. Weak storms have already developed near the CO Front Range, with building cumulus noted in the vicinity of multiple surface confluence zones across northeast CO, east-central CO, and southeast CO into southwest KS. Westerly midlevel flow is relatively modest (generally 20-25 kt), but sufficient veering in the wind profile is supporting effective shear of 25-30 kt. With time, a few organized multicells and perhaps a marginal supercell or two could evolve as developing convection deepens and matures through late afternoon. The strongest cells could produce isolated hail, though generally weak midlevel lapse rates will tend to limit the magnitude of the hail threat. Outflow amalgamation could result in loosely organized upscale growth by early evening, with a threat for strong to locally severe gusts. ..Dean/Gleason.. 08/27/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DDC...GLD...PUB...BOU...CYS... LAT...LON 40720462 40840406 41210382 41490378 41510312 41050292 39860214 38760137 37820072 37200076 37180183 37290306 38450481 39500491 40360518 40700483 40720462 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

MD 2015 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST MINNESOTA AND FAR EASTERN SOUTH DAKOTA
Mesoscale Discussion 2015 NWS Storm Prediction Center Norman OK 0218 PM CDT Wed Aug 27 2025 Areas affected...Southwest Minnesota and far eastern South Dakota Concerning...Severe potential...Watch unlikely Valid 271918Z - 272145Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorm coverage should increase through early evening across southwest Minnesota and perhaps far eastern South Dakota. A strong to severe thunderstorm or two is possible, but watch issuance is not expected. DISCUSSION...Latest GOES imagery shows a band of growing cumulus focused along a subtle warm frontal zone from eastern SD into south-central MN. Vertical development of the cumulus has increased over the past hour (with occasional lightning flashes noted in at least one deeper convective tower) as modest daytime heating slowly reduces inhibition and ascent ahead of a weak upper-level wave (noted in water-vapor imagery and regional VWP observations) glances the region. Additional convective development should become more likely through late afternoon/early evening as temperatures continue to warm into the mid/upper 70s and the upper wave overspreads southern MN. VWP observations from KFSD have consistently sampled around 30 knots of 0-4 km shear, and recent RAP forecast soundings/mesoanalysis estimates suggest MLCAPE is approaching 1000 J/kg. While fairly modest, this environment is sufficient for some storm organization if mature convection can become established within the weakly forced regime. More intense cells may be capable of severe gusts as well as large hail, though the coverage and overall intensity of severe thunderstorms is expected to remain fairly limited through early evening. ..Moore/Gleason.. 08/27/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...DMX...FSD...ABR... LAT...LON 45079626 45039549 44929487 44769447 44589405 44329363 44039334 43729336 43529346 43429383 43419435 43449505 43539565 43659608 43829655 44129698 44399719 44659725 44939717 45069685 45079626 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0409 PM CDT Wed Aug 27 2025 Valid 291200Z - 041200Z A closed upper low will approach the Pacific Northwest Coast Day 3/Friday - Day 4/Saturday, but forecast guidance has been inconsistent on how far inland the low moves over British Columbia and Washington. Forecast guidance has been increasingly consistent in the low retrograding back offshore early next week. Meanwhile, upper-level ridging will slowly build back over the West, especially the Intermountain West, this weekend through early next week with a warming and drying trend. Thunderstorm coverage will diminish across the West and likely be mostly confined to portions of the Four Corners region this weekend into early next week. ...Day 3/Friday - Day 5/Sunday... As the upper low approaches the Northwest, dry/breezy conditions are likely in portions of northern California, Inland Northwest, and northwest Great Basin Day 3/Friday - Day 5/Sunday. Current forecast guidance indicates the potential for locally elevated winds/RH and low probabilities of critical conditions. However, given the recent lightning, holdovers will be a concern. Established fires are also likely to see increased burn periods and lower RH/higher winds helping to increase spread potential. Isolated drier thunderstorms are possible ahead of the upper low across portions of the Northwest, northwest Great Basin, and northern Rockies Day 3/Friday and possibly into Day 4/Saturday. However, too much forecast uncertainty exists to include probabilities at this time. Showers are likely for portions of northwest Oregon and western Washington associated with the upper low Day 3/Friday into Day 5/Sunday. ..Nauslar.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Aug 27 2025 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE CENTRAL HIGH PLAINS AND THE UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms may occur across parts of the central High Plains and Upper Midwest this afternoon and early evening. ...20Z Update... The forecast remains on track with only minor adjustments to the general thunderstorm forecast. See the previous discussion for additional information. ..Wendt.. 08/27/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 27 2025/ ...Central High Plains... Upper ridging should remain suppressed over TX today, with modest mid-level westerly flow persisting across the central Plains. Late morning visible satellite imagery shows some clearing across eastern CO, which should aid in diurnal destabilization this afternoon. Gradual low-level moisture return is forecast to continue today across the central High Plains, generally along and east of a weak lee trough/low where low to mid 60s surface dewpoints are present. With scattered to numerous thunderstorms over much of the Southwest and southern/central Rockies yesterday, there is not a notable EML present over the central High Plains today (reference 12Z observed DDC sounding). This should temper the degree of instability that can develop through the afternoon to some extent. Even so, around 500-1500 J/kg of MLCAPE appears plausible with additional diurnal heating of the modestly moistened low-level airmass. Weak low-level southerly flow will veer to westerly and gradually strengthen with height through mid/upper levels, supporting around 25-40 kt of deep-layer shear. Thunderstorms are expected to develop initially along/near the Front Range this afternoon, before spreading slowly east-southeastward across eastern CO and parts of western KS through the evening. Isolated severe hail may occur with the strongest cores/marginal supercell structures, until gradual outflow/cold pool amalgamation encourages one or more clusters with a greater threat for occasional strong to severe gusts. Based on latest observational and short-term guidance trends, the Marginal Risk has been expanded to include more of eastern CO and western KS. Mainly elevated thunderstorms will likely continue overnight into central/eastern KS in a modest low-level warm advection regime. However, confidence in a continued hail/wind threat with this activity remains low at this time. ...Upper Midwest... On the western side of a large-scale upper trough over eastern Canada and the Atlantic Coast states, modestly enhanced northwesterly mid-level flow is forecast to persist through much of the period. A weak embedded shortwave trough moving across southern MN and vicinity late this morning suggests modest large-scale subsidence in its wake. This casts some uncertainty on the possible development of isolated to scattered thunderstorms later today along/south of a weak surface trough across eastern SD into central/southern MN. Even so, most guidance suggests at least isolated thunderstorms will form across this region by late afternoon/early evening. Cool mid-level temperatures and generally long/straight hodographs aloft suggest some threat for severe hail with any of the stronger cores that can be sustained. Have therefore added a focused Marginal Risk across parts of eastern SD into southern MN for this potential. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Aug 27 2025 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE CENTRAL HIGH PLAINS AND THE UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms may occur across parts of the central High Plains and Upper Midwest this afternoon and early evening. ...20Z Update... The forecast remains on track with only minor adjustments to the general thunderstorm forecast. See the previous discussion for additional information. ..Wendt.. 08/27/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 27 2025/ ...Central High Plains... Upper ridging should remain suppressed over TX today, with modest mid-level westerly flow persisting across the central Plains. Late morning visible satellite imagery shows some clearing across eastern CO, which should aid in diurnal destabilization this afternoon. Gradual low-level moisture return is forecast to continue today across the central High Plains, generally along and east of a weak lee trough/low where low to mid 60s surface dewpoints are present. With scattered to numerous thunderstorms over much of the Southwest and southern/central Rockies yesterday, there is not a notable EML present over the central High Plains today (reference 12Z observed DDC sounding). This should temper the degree of instability that can develop through the afternoon to some extent. Even so, around 500-1500 J/kg of MLCAPE appears plausible with additional diurnal heating of the modestly moistened low-level airmass. Weak low-level southerly flow will veer to westerly and gradually strengthen with height through mid/upper levels, supporting around 25-40 kt of deep-layer shear. Thunderstorms are expected to develop initially along/near the Front Range this afternoon, before spreading slowly east-southeastward across eastern CO and parts of western KS through the evening. Isolated severe hail may occur with the strongest cores/marginal supercell structures, until gradual outflow/cold pool amalgamation encourages one or more clusters with a greater threat for occasional strong to severe gusts. Based on latest observational and short-term guidance trends, the Marginal Risk has been expanded to include more of eastern CO and western KS. Mainly elevated thunderstorms will likely continue overnight into central/eastern KS in a modest low-level warm advection regime. However, confidence in a continued hail/wind threat with this activity remains low at this time. ...Upper Midwest... On the western side of a large-scale upper trough over eastern Canada and the Atlantic Coast states, modestly enhanced northwesterly mid-level flow is forecast to persist through much of the period. A weak embedded shortwave trough moving across southern MN and vicinity late this morning suggests modest large-scale subsidence in its wake. This casts some uncertainty on the possible development of isolated to scattered thunderstorms later today along/south of a weak surface trough across eastern SD into central/southern MN. Even so, most guidance suggests at least isolated thunderstorms will form across this region by late afternoon/early evening. Cool mid-level temperatures and generally long/straight hodographs aloft suggest some threat for severe hail with any of the stronger cores that can be sustained. Have therefore added a focused Marginal Risk across parts of eastern SD into southern MN for this potential. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Wed Aug 27 2025 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE CENTRAL HIGH PLAINS AND THE UPPER MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms may occur across parts of the central High Plains and Upper Midwest this afternoon and early evening. ...20Z Update... The forecast remains on track with only minor adjustments to the general thunderstorm forecast. See the previous discussion for additional information. ..Wendt.. 08/27/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 27 2025/ ...Central High Plains... Upper ridging should remain suppressed over TX today, with modest mid-level westerly flow persisting across the central Plains. Late morning visible satellite imagery shows some clearing across eastern CO, which should aid in diurnal destabilization this afternoon. Gradual low-level moisture return is forecast to continue today across the central High Plains, generally along and east of a weak lee trough/low where low to mid 60s surface dewpoints are present. With scattered to numerous thunderstorms over much of the Southwest and southern/central Rockies yesterday, there is not a notable EML present over the central High Plains today (reference 12Z observed DDC sounding). This should temper the degree of instability that can develop through the afternoon to some extent. Even so, around 500-1500 J/kg of MLCAPE appears plausible with additional diurnal heating of the modestly moistened low-level airmass. Weak low-level southerly flow will veer to westerly and gradually strengthen with height through mid/upper levels, supporting around 25-40 kt of deep-layer shear. Thunderstorms are expected to develop initially along/near the Front Range this afternoon, before spreading slowly east-southeastward across eastern CO and parts of western KS through the evening. Isolated severe hail may occur with the strongest cores/marginal supercell structures, until gradual outflow/cold pool amalgamation encourages one or more clusters with a greater threat for occasional strong to severe gusts. Based on latest observational and short-term guidance trends, the Marginal Risk has been expanded to include more of eastern CO and western KS. Mainly elevated thunderstorms will likely continue overnight into central/eastern KS in a modest low-level warm advection regime. However, confidence in a continued hail/wind threat with this activity remains low at this time. ...Upper Midwest... On the western side of a large-scale upper trough over eastern Canada and the Atlantic Coast states, modestly enhanced northwesterly mid-level flow is forecast to persist through much of the period. A weak embedded shortwave trough moving across southern MN and vicinity late this morning suggests modest large-scale subsidence in its wake. This casts some uncertainty on the possible development of isolated to scattered thunderstorms later today along/south of a weak surface trough across eastern SD into central/southern MN. Even so, most guidance suggests at least isolated thunderstorms will form across this region by late afternoon/early evening. Cool mid-level temperatures and generally long/straight hodographs aloft suggest some threat for severe hail with any of the stronger cores that can be sustained. Have therefore added a focused Marginal Risk across parts of eastern SD into southern MN for this potential. Read more