Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0754 AM CDT Fri Jul 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across the Midwest to southern portions of the Great Lakes region, accompanied by a risk for damaging wind gusts, hail, as well as some tornado potential. Severe thunderstorms are also expected across the central/southern High Plains and Upper Midwest. ...Midwest/Lower Missouri Valley to Great Lakes... A decayed overnight MCS and residual convection/cloud cover will reinforce the baroclinic zone regionally. Near/south of the boundary, surface dew points near and above 70F, beneath modestly steep mid-level lapse rates, are forecast to contribute to CAPE on the order of 2000-3000 J/kg. This will be beneath a lingering belt of convectively augmented mid-level flow (on the order of 30-50 kt in the 700-500 mb layer). Coupled with modest, clockwise-curved low-level hodographs in advance of a weak surface wave, the environment should become conducive to supercell structures into mid/late afternoon. These supercells may pose a risk for hail and potentially a couple of tornadoes across parts of northern Missouri and southern/eastern Iowa into northern Illinois, and possibly far southern Wisconsin. Damaging wind gusts should become the more predominant potential hazard as convection tends to grow upscale into east/southeastward-moving clusters this evening. ...Central High Plains... The immediate post-frontal regime should be favorable for severe storm development this afternoon into evening across southeast Wyoming and northeast Colorado into southwest Nebraska/northwest Kansas. Some initial supercells capable of large hail can be expected, and one or more east/eastward-moving clusters may evolve by evening with severe-caliber winds also a possibility. ...Upper Midwest... At least isolated strong to severe thunderstorms can be expected near the east/southeastward-moving front this afternoon, including the eastern Dakotas into much of Minnesota. This will be influenced by the amplifying upper-level trough approaching the Dakotas/northern Minnesota. The strongest winds aloft/vertical shear will tend to lag the front, but ample near/pre-frontal buoyancy will support storms capable of hail/wind. ...Southern Rockies into the Great Plains... Thermodynamic profiles characterized by modest low-level moisture, but with generally steep lapse rates, including fairly deep boundary-layer mixing, may become conducive to scattered thunderstorm clusters posing a risk for severe wind and hail late this afternoon and evening. A degree of storm organization may be aided by modest shear beneath northwesterly mid-level flow, with thunderstorm activity mostly initiating off the higher terrain of the Front Range through Sangre de Cristo Mountains. Additionally, low-level convergence within surface troughing across southern Kansas through the Oklahoma/Texas Panhandle vicinity may also become sufficient for thunderstorm initiation during the peak late afternoon heating, and one or more semi-organized clusters capable of wind damage could evolve. This region will be reevaluated in subsequent outlooks for potential inclusion of a wind-related Slight Risk. ..Guyer/Bentley.. 07/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0754 AM CDT Fri Jul 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across the Midwest to southern portions of the Great Lakes region, accompanied by a risk for damaging wind gusts, hail, as well as some tornado potential. Severe thunderstorms are also expected across the central/southern High Plains and Upper Midwest. ...Midwest/Lower Missouri Valley to Great Lakes... A decayed overnight MCS and residual convection/cloud cover will reinforce the baroclinic zone regionally. Near/south of the boundary, surface dew points near and above 70F, beneath modestly steep mid-level lapse rates, are forecast to contribute to CAPE on the order of 2000-3000 J/kg. This will be beneath a lingering belt of convectively augmented mid-level flow (on the order of 30-50 kt in the 700-500 mb layer). Coupled with modest, clockwise-curved low-level hodographs in advance of a weak surface wave, the environment should become conducive to supercell structures into mid/late afternoon. These supercells may pose a risk for hail and potentially a couple of tornadoes across parts of northern Missouri and southern/eastern Iowa into northern Illinois, and possibly far southern Wisconsin. Damaging wind gusts should become the more predominant potential hazard as convection tends to grow upscale into east/southeastward-moving clusters this evening. ...Central High Plains... The immediate post-frontal regime should be favorable for severe storm development this afternoon into evening across southeast Wyoming and northeast Colorado into southwest Nebraska/northwest Kansas. Some initial supercells capable of large hail can be expected, and one or more east/eastward-moving clusters may evolve by evening with severe-caliber winds also a possibility. ...Upper Midwest... At least isolated strong to severe thunderstorms can be expected near the east/southeastward-moving front this afternoon, including the eastern Dakotas into much of Minnesota. This will be influenced by the amplifying upper-level trough approaching the Dakotas/northern Minnesota. The strongest winds aloft/vertical shear will tend to lag the front, but ample near/pre-frontal buoyancy will support storms capable of hail/wind. ...Southern Rockies into the Great Plains... Thermodynamic profiles characterized by modest low-level moisture, but with generally steep lapse rates, including fairly deep boundary-layer mixing, may become conducive to scattered thunderstorm clusters posing a risk for severe wind and hail late this afternoon and evening. A degree of storm organization may be aided by modest shear beneath northwesterly mid-level flow, with thunderstorm activity mostly initiating off the higher terrain of the Front Range through Sangre de Cristo Mountains. Additionally, low-level convergence within surface troughing across southern Kansas through the Oklahoma/Texas Panhandle vicinity may also become sufficient for thunderstorm initiation during the peak late afternoon heating, and one or more semi-organized clusters capable of wind damage could evolve. This region will be reevaluated in subsequent outlooks for potential inclusion of a wind-related Slight Risk. ..Guyer/Bentley.. 07/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0754 AM CDT Fri Jul 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across the Midwest to southern portions of the Great Lakes region, accompanied by a risk for damaging wind gusts, hail, as well as some tornado potential. Severe thunderstorms are also expected across the central/southern High Plains and Upper Midwest. ...Midwest/Lower Missouri Valley to Great Lakes... A decayed overnight MCS and residual convection/cloud cover will reinforce the baroclinic zone regionally. Near/south of the boundary, surface dew points near and above 70F, beneath modestly steep mid-level lapse rates, are forecast to contribute to CAPE on the order of 2000-3000 J/kg. This will be beneath a lingering belt of convectively augmented mid-level flow (on the order of 30-50 kt in the 700-500 mb layer). Coupled with modest, clockwise-curved low-level hodographs in advance of a weak surface wave, the environment should become conducive to supercell structures into mid/late afternoon. These supercells may pose a risk for hail and potentially a couple of tornadoes across parts of northern Missouri and southern/eastern Iowa into northern Illinois, and possibly far southern Wisconsin. Damaging wind gusts should become the more predominant potential hazard as convection tends to grow upscale into east/southeastward-moving clusters this evening. ...Central High Plains... The immediate post-frontal regime should be favorable for severe storm development this afternoon into evening across southeast Wyoming and northeast Colorado into southwest Nebraska/northwest Kansas. Some initial supercells capable of large hail can be expected, and one or more east/eastward-moving clusters may evolve by evening with severe-caliber winds also a possibility. ...Upper Midwest... At least isolated strong to severe thunderstorms can be expected near the east/southeastward-moving front this afternoon, including the eastern Dakotas into much of Minnesota. This will be influenced by the amplifying upper-level trough approaching the Dakotas/northern Minnesota. The strongest winds aloft/vertical shear will tend to lag the front, but ample near/pre-frontal buoyancy will support storms capable of hail/wind. ...Southern Rockies into the Great Plains... Thermodynamic profiles characterized by modest low-level moisture, but with generally steep lapse rates, including fairly deep boundary-layer mixing, may become conducive to scattered thunderstorm clusters posing a risk for severe wind and hail late this afternoon and evening. A degree of storm organization may be aided by modest shear beneath northwesterly mid-level flow, with thunderstorm activity mostly initiating off the higher terrain of the Front Range through Sangre de Cristo Mountains. Additionally, low-level convergence within surface troughing across southern Kansas through the Oklahoma/Texas Panhandle vicinity may also become sufficient for thunderstorm initiation during the peak late afternoon heating, and one or more semi-organized clusters capable of wind damage could evolve. This region will be reevaluated in subsequent outlooks for potential inclusion of a wind-related Slight Risk. ..Guyer/Bentley.. 07/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0754 AM CDT Fri Jul 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across the Midwest to southern portions of the Great Lakes region, accompanied by a risk for damaging wind gusts, hail, as well as some tornado potential. Severe thunderstorms are also expected across the central/southern High Plains and Upper Midwest. ...Midwest/Lower Missouri Valley to Great Lakes... A decayed overnight MCS and residual convection/cloud cover will reinforce the baroclinic zone regionally. Near/south of the boundary, surface dew points near and above 70F, beneath modestly steep mid-level lapse rates, are forecast to contribute to CAPE on the order of 2000-3000 J/kg. This will be beneath a lingering belt of convectively augmented mid-level flow (on the order of 30-50 kt in the 700-500 mb layer). Coupled with modest, clockwise-curved low-level hodographs in advance of a weak surface wave, the environment should become conducive to supercell structures into mid/late afternoon. These supercells may pose a risk for hail and potentially a couple of tornadoes across parts of northern Missouri and southern/eastern Iowa into northern Illinois, and possibly far southern Wisconsin. Damaging wind gusts should become the more predominant potential hazard as convection tends to grow upscale into east/southeastward-moving clusters this evening. ...Central High Plains... The immediate post-frontal regime should be favorable for severe storm development this afternoon into evening across southeast Wyoming and northeast Colorado into southwest Nebraska/northwest Kansas. Some initial supercells capable of large hail can be expected, and one or more east/eastward-moving clusters may evolve by evening with severe-caliber winds also a possibility. ...Upper Midwest... At least isolated strong to severe thunderstorms can be expected near the east/southeastward-moving front this afternoon, including the eastern Dakotas into much of Minnesota. This will be influenced by the amplifying upper-level trough approaching the Dakotas/northern Minnesota. The strongest winds aloft/vertical shear will tend to lag the front, but ample near/pre-frontal buoyancy will support storms capable of hail/wind. ...Southern Rockies into the Great Plains... Thermodynamic profiles characterized by modest low-level moisture, but with generally steep lapse rates, including fairly deep boundary-layer mixing, may become conducive to scattered thunderstorm clusters posing a risk for severe wind and hail late this afternoon and evening. A degree of storm organization may be aided by modest shear beneath northwesterly mid-level flow, with thunderstorm activity mostly initiating off the higher terrain of the Front Range through Sangre de Cristo Mountains. Additionally, low-level convergence within surface troughing across southern Kansas through the Oklahoma/Texas Panhandle vicinity may also become sufficient for thunderstorm initiation during the peak late afternoon heating, and one or more semi-organized clusters capable of wind damage could evolve. This region will be reevaluated in subsequent outlooks for potential inclusion of a wind-related Slight Risk. ..Guyer/Bentley.. 07/11/2025 Read more

MD 1640 CONCERNING SEVERE THUNDERSTORM WATCH 504... FOR EAST-CENTRAL IOWA INTO PARTS OF FAR NORTHWESTERN ILLINOIS
Mesoscale Discussion 1640 NWS Storm Prediction Center Norman OK 0243 AM CDT Fri Jul 11 2025 Areas affected...east-central Iowa into parts of far northwestern Illinois Concerning...Severe Thunderstorm Watch 504... Valid 110743Z - 110915Z The severe weather threat for Severe Thunderstorm Watch 504 continues. SUMMARY...Some severe wind threat continues across eastern Iowa and parts of far northwestern Illinois. DISCUSSION...A bowing line of storms which has produced measured winds as high as 64 knots (at KDSM) continues east across east-central Iowa. This line of storms is not currently as strong as it was across central Iowa. However, recent satellite data shows recent cooling cloud ops associated with this convection and additional development along the front ahead of the line. This may result in some strengthening/rejuvenation of the line as it moves across far eastern Iowa and parts of far northwestern Illinois within an environment featuring 2000 J/kg MUCAPE. Damaging wind gusts will likely remain the primary threat from this activity. ..Bentley/Guyer.. 07/11/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DVN...DMX... LAT...LON 41959254 42019197 41929124 41729069 41639054 41429050 41259049 41139069 41129110 41169173 41229227 41279248 41959254 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0340 AM CDT Fri Jul 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... A surface cold front across the southern Great Plains early in the period will quickly redevelop northward into the northern Plains in response to strong lee cyclogenesis across the northern High Plains. This cyclogenesis will occur in response to a positive-tilt short-wave trough moving through the broadly zonal mid-level flow across the northern US. This front will move back south during the period as a seasonably strong high pressure builds southward into the central US in the wake of the aforementioned short-wave trough. Thunderstorms are likely to develop in the vicinity of the front/aggregate outflow boundary each afternoon as it moves south. However, given the lack of significant flow amplification as the mid-level wave crosses the northern US, it is likely that thunderstorms will remain displaced south of the requisite effective-layer shear needed to promote an organized severe threat identifiable at this time range. One exception to the idea that storms will be displaced from the better shear may take place on Monday/Day-4 across portions of North Dakota. Here, low-level moisture will surge northward in response to the aforementioned northern High Plains lee cyclogenesis. Steep mid-level lapse rates will overspread the northern Great Plains during the day, yielding most-unstable CAPE values ranging from 1000 J/kg to perhaps 3000 J/kg depending on model guidance. However, run-to-run inconsistency in the space and time evolution of relevant features leads to little confidence in identifying where any overlap of thunderstorms, instability, and effective-layer shear might support severe thunderstorms. However, if model guidance begins to converge on potential scenarios, probabilistic delineation may become warranted in subsequent forecasts. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Fri Jul 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC NORTH INTO WESTERN AND UPSTATE NEW YORK AS WELL AS ACROSS THE SOUTHERN GREAT PLAINS NORTHEAST INTO THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Marginally severe thunderstorms will be possible across the eastern US from the mid-Atlantic region northward into upstate New York. Additional strong-to-severe thunderstorms will be possible across the southern Great Plains northeast into the Mid-Mississippi Valley. ... Synopsis ... Broadly cyclonic mid-level flow will overspread the northeast United States on Sunday. At the same time, a surface cold front will slowly move east across the eastern US. Farther southwest, across the southern Great Plains, the aforementioned cold front will make little southward progress as southerly low-level flow increases in response to surface cyclogenesis across the northern High Plains late in the period. ... Mid-Atlantic northward into Upstate New York ... Numerous thunderstorms are expected to develop from late morning into the early afternoon associated with a modest increase in large-scale ascent and surface convergence along the cold front. Ahead of the front, surface dewpoints in the mid 60Fs to low 70Fs will combine with diurnal heating to result in most-unstable CAPE values in excess of 1500 J/kg. Despite the better effective-layer shear remaining north of the US, the degree of instability and the very moist airmass will support sporadic wind damage with the strongest thunderstorms. ... Southern Great Plains into the Mid-Mississippi Valley ... Multiple MCVs from the preceding days convection will likely be located across the region through the forecast period. A very moist airmass -- precipitable water values in excess of 2 inches in places -- and diurnal heating will result in a strongly unstable and weakly capped airmass. Although thunderstorms will be possible across the totality of the delineated area, it is likely that pockets of more concentrated thunderstorm activity will develop in the vicinity of the aforementioned MCVs. Some severe potential -- likely damaging wind gusts -- will be possible with the strongest storms. ..Marsh.. 07/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Fri Jul 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC NORTH INTO WESTERN AND UPSTATE NEW YORK AS WELL AS ACROSS THE SOUTHERN GREAT PLAINS NORTHEAST INTO THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Marginally severe thunderstorms will be possible across the eastern US from the mid-Atlantic region northward into upstate New York. Additional strong-to-severe thunderstorms will be possible across the southern Great Plains northeast into the Mid-Mississippi Valley. ... Synopsis ... Broadly cyclonic mid-level flow will overspread the northeast United States on Sunday. At the same time, a surface cold front will slowly move east across the eastern US. Farther southwest, across the southern Great Plains, the aforementioned cold front will make little southward progress as southerly low-level flow increases in response to surface cyclogenesis across the northern High Plains late in the period. ... Mid-Atlantic northward into Upstate New York ... Numerous thunderstorms are expected to develop from late morning into the early afternoon associated with a modest increase in large-scale ascent and surface convergence along the cold front. Ahead of the front, surface dewpoints in the mid 60Fs to low 70Fs will combine with diurnal heating to result in most-unstable CAPE values in excess of 1500 J/kg. Despite the better effective-layer shear remaining north of the US, the degree of instability and the very moist airmass will support sporadic wind damage with the strongest thunderstorms. ... Southern Great Plains into the Mid-Mississippi Valley ... Multiple MCVs from the preceding days convection will likely be located across the region through the forecast period. A very moist airmass -- precipitable water values in excess of 2 inches in places -- and diurnal heating will result in a strongly unstable and weakly capped airmass. Although thunderstorms will be possible across the totality of the delineated area, it is likely that pockets of more concentrated thunderstorm activity will develop in the vicinity of the aforementioned MCVs. Some severe potential -- likely damaging wind gusts -- will be possible with the strongest storms. ..Marsh.. 07/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Fri Jul 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC NORTH INTO WESTERN AND UPSTATE NEW YORK AS WELL AS ACROSS THE SOUTHERN GREAT PLAINS NORTHEAST INTO THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Marginally severe thunderstorms will be possible across the eastern US from the mid-Atlantic region northward into upstate New York. Additional strong-to-severe thunderstorms will be possible across the southern Great Plains northeast into the Mid-Mississippi Valley. ... Synopsis ... Broadly cyclonic mid-level flow will overspread the northeast United States on Sunday. At the same time, a surface cold front will slowly move east across the eastern US. Farther southwest, across the southern Great Plains, the aforementioned cold front will make little southward progress as southerly low-level flow increases in response to surface cyclogenesis across the northern High Plains late in the period. ... Mid-Atlantic northward into Upstate New York ... Numerous thunderstorms are expected to develop from late morning into the early afternoon associated with a modest increase in large-scale ascent and surface convergence along the cold front. Ahead of the front, surface dewpoints in the mid 60Fs to low 70Fs will combine with diurnal heating to result in most-unstable CAPE values in excess of 1500 J/kg. Despite the better effective-layer shear remaining north of the US, the degree of instability and the very moist airmass will support sporadic wind damage with the strongest thunderstorms. ... Southern Great Plains into the Mid-Mississippi Valley ... Multiple MCVs from the preceding days convection will likely be located across the region through the forecast period. A very moist airmass -- precipitable water values in excess of 2 inches in places -- and diurnal heating will result in a strongly unstable and weakly capped airmass. Although thunderstorms will be possible across the totality of the delineated area, it is likely that pockets of more concentrated thunderstorm activity will develop in the vicinity of the aforementioned MCVs. Some severe potential -- likely damaging wind gusts -- will be possible with the strongest storms. ..Marsh.. 07/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Fri Jul 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC NORTH INTO WESTERN AND UPSTATE NEW YORK AS WELL AS ACROSS THE SOUTHERN GREAT PLAINS NORTHEAST INTO THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Marginally severe thunderstorms will be possible across the eastern US from the mid-Atlantic region northward into upstate New York. Additional strong-to-severe thunderstorms will be possible across the southern Great Plains northeast into the Mid-Mississippi Valley. ... Synopsis ... Broadly cyclonic mid-level flow will overspread the northeast United States on Sunday. At the same time, a surface cold front will slowly move east across the eastern US. Farther southwest, across the southern Great Plains, the aforementioned cold front will make little southward progress as southerly low-level flow increases in response to surface cyclogenesis across the northern High Plains late in the period. ... Mid-Atlantic northward into Upstate New York ... Numerous thunderstorms are expected to develop from late morning into the early afternoon associated with a modest increase in large-scale ascent and surface convergence along the cold front. Ahead of the front, surface dewpoints in the mid 60Fs to low 70Fs will combine with diurnal heating to result in most-unstable CAPE values in excess of 1500 J/kg. Despite the better effective-layer shear remaining north of the US, the degree of instability and the very moist airmass will support sporadic wind damage with the strongest thunderstorms. ... Southern Great Plains into the Mid-Mississippi Valley ... Multiple MCVs from the preceding days convection will likely be located across the region through the forecast period. A very moist airmass -- precipitable water values in excess of 2 inches in places -- and diurnal heating will result in a strongly unstable and weakly capped airmass. Although thunderstorms will be possible across the totality of the delineated area, it is likely that pockets of more concentrated thunderstorm activity will develop in the vicinity of the aforementioned MCVs. Some severe potential -- likely damaging wind gusts -- will be possible with the strongest storms. ..Marsh.. 07/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Fri Jul 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC NORTH INTO WESTERN AND UPSTATE NEW YORK AS WELL AS ACROSS THE SOUTHERN GREAT PLAINS NORTHEAST INTO THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Marginally severe thunderstorms will be possible across the eastern US from the mid-Atlantic region northward into upstate New York. Additional strong-to-severe thunderstorms will be possible across the southern Great Plains northeast into the Mid-Mississippi Valley. ... Synopsis ... Broadly cyclonic mid-level flow will overspread the northeast United States on Sunday. At the same time, a surface cold front will slowly move east across the eastern US. Farther southwest, across the southern Great Plains, the aforementioned cold front will make little southward progress as southerly low-level flow increases in response to surface cyclogenesis across the northern High Plains late in the period. ... Mid-Atlantic northward into Upstate New York ... Numerous thunderstorms are expected to develop from late morning into the early afternoon associated with a modest increase in large-scale ascent and surface convergence along the cold front. Ahead of the front, surface dewpoints in the mid 60Fs to low 70Fs will combine with diurnal heating to result in most-unstable CAPE values in excess of 1500 J/kg. Despite the better effective-layer shear remaining north of the US, the degree of instability and the very moist airmass will support sporadic wind damage with the strongest thunderstorms. ... Southern Great Plains into the Mid-Mississippi Valley ... Multiple MCVs from the preceding days convection will likely be located across the region through the forecast period. A very moist airmass -- precipitable water values in excess of 2 inches in places -- and diurnal heating will result in a strongly unstable and weakly capped airmass. Although thunderstorms will be possible across the totality of the delineated area, it is likely that pockets of more concentrated thunderstorm activity will develop in the vicinity of the aforementioned MCVs. Some severe potential -- likely damaging wind gusts -- will be possible with the strongest storms. ..Marsh.. 07/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Fri Jul 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-ATLANTIC NORTH INTO WESTERN AND UPSTATE NEW YORK AS WELL AS ACROSS THE SOUTHERN GREAT PLAINS NORTHEAST INTO THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Marginally severe thunderstorms will be possible across the eastern US from the mid-Atlantic region northward into upstate New York. Additional strong-to-severe thunderstorms will be possible across the southern Great Plains northeast into the Mid-Mississippi Valley. ... Synopsis ... Broadly cyclonic mid-level flow will overspread the northeast United States on Sunday. At the same time, a surface cold front will slowly move east across the eastern US. Farther southwest, across the southern Great Plains, the aforementioned cold front will make little southward progress as southerly low-level flow increases in response to surface cyclogenesis across the northern High Plains late in the period. ... Mid-Atlantic northward into Upstate New York ... Numerous thunderstorms are expected to develop from late morning into the early afternoon associated with a modest increase in large-scale ascent and surface convergence along the cold front. Ahead of the front, surface dewpoints in the mid 60Fs to low 70Fs will combine with diurnal heating to result in most-unstable CAPE values in excess of 1500 J/kg. Despite the better effective-layer shear remaining north of the US, the degree of instability and the very moist airmass will support sporadic wind damage with the strongest thunderstorms. ... Southern Great Plains into the Mid-Mississippi Valley ... Multiple MCVs from the preceding days convection will likely be located across the region through the forecast period. A very moist airmass -- precipitable water values in excess of 2 inches in places -- and diurnal heating will result in a strongly unstable and weakly capped airmass. Although thunderstorms will be possible across the totality of the delineated area, it is likely that pockets of more concentrated thunderstorm activity will develop in the vicinity of the aforementioned MCVs. Some severe potential -- likely damaging wind gusts -- will be possible with the strongest storms. ..Marsh.. 07/11/2025 Read more