The Storm Prediction Center convective weather outlook is part of the National Weather Service (NWS) and the National Center for Environmental Prediction (NCEP). Their mission is to provide accurate forecasts and monitor the timing of thunderstorms and severe storms in the United States. The SPC provides convective outlooks on Day 1, Day 2, and Day 3 that reflect the overall level of severe weather hazard outlooks through a list of forecast statistics. This data identifies areas at risk of mild thunderstorms and severe thunderstorms. For more information on how to read this map, please see the bottom of this page.
Convective Outlook Day 1
SPC Day 1 Outlook Discussion
ACUS01 KWNS 190516 SWODY1 SPC AC 190514 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1214 AM CDT Sat Sep 19 2026 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Thunderstorms with scattered severe wind gusts and large hail are possible this afternoon and evening across parts of the central Plains. Isolated severe wind gusts and hail may occur in parts of the southern Plains and lower Missouri Valley. Isolated severe gusts will also be possible from the Ohio Valley southward into the Southeast. ...Central and Southern Plains/Lower Missouri Valley... Mid-level heights will steadily fall over the central U.S. today, as southwesterly flow aloft becomes established over much of the region. At the surface, a cold front will advance southeastward across the central Plains, and should be positioned from central Kansas to far northwest Missouri by late afternoon. Ahead of the front, surface dewpoints will be mostly from the mid 60s to mid 70s F. As surface temperatures warm today, the moisture will contribute to moderate destabilization. Thunderstorm initiation will become likely by late afternoon across central and eastern Kansas, as low-level convergence increases along and ahead of the front. A complex of organized storms is expected to become established by early evening and should persist for several hours. RAP forecast soundings by early evening near the instability axis have 0-6 km shear in the 30 to 40 knot range, with substantial directional shear in the low-levels. In addition, low to mid-level lapse rates are forecast to become steep. This environment should support a large hail threat with supercells. A wind-damage threat will also be possible, especially if a line segment can persist and become organized during the evening. A marginal severe threat may also develop southwestward across parts of the southern High Plains, where hail and isolated severe gusts will be possible in the late afternoon and early evening. ...Central High Plains... An upper-level trough will move eastward across the Intermountain West today, as flow aloft remains southwesterly over the central Rockies and central High Plains. At the surface, a cold front will advance southward across southeastern Colorado and western Kansas. Behind the front, surface dewpoints in eastern Colorado will be in the upper 50s to lower 60s F. The moisture will enable moderate destabilization over much of eastern Colorado by afternoon. Warming surface temperatures will lead to scattered thunderstorm development in the higher terrain, with this convection moving eastward into the central High Plains during the late afternoon. RAP forecast soundings at 21Z in eastern Colorado have 0-6 shear in the 35 to 40 knot range, with 700-500 mb lapse rates near 8 C/km. This environment will likely support a threat for large hail with supercells. Isolated severe wind gusts will also be possible. A marginal severe threat may also develop further north into parts of eastern Wyoming and far western Nebraska, but instability will remain relatively weak there. ...Ohio Valley/Southern Appalachians/Southeast... West-northwesterly mid-level flow will be located over much of the northeastern third of the U.S today. At the surface, an axis of low-level moisture will be oriented from the Ohio Valley southward into the southern Appalachians, along which moderate instability is expected to be in place by afternoon. Convective development will be possible in parts of the airmass, where localized surface heating and low-level convergence become maximized. Thunderstorms in areas with moderate instability could produce isolated severe wind gusts, mainly during the late afternoon and early evening. ..Broyles/Thornton.. 09/19/2026 $$ |
Convective Outlook Day 2
SPC Day 2 Outlook Discussion
ACUS02 KWNS 190547 SWODY2 SPC AC 190546 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Sat Sep 19 2026 Valid 201200Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO EASTERN OKLAHOMA AND THE COLORADO FRONT RANGE... ...SUMMARY... A few severe wind and hail producing thunderstorms are possible over eastern Colorado, with severe gusts also likely to accompany storms over portions of Oklahoma tomorrow (Sunday). Isolated severe thunderstorms are also possible from the Ozark Valley to the central Appalachians. ...Synopsis... Multiple mid-level impulses will pivot around a de-amplifying upper ridge and traverse the central CONUS tomorrow (Sunday). These impulses will encourage the gradual southward progression of a surface cold front, preceded by a seasonably moist and unstable boundary layer, to support thunderstorm development across much of the southern Plains to the OH Valley. Given stronger buoyancy in proximity to the cold front, severe thunderstorms are possible, especially over the southern Plains. Upslope flow along the western flank of the cold front into the central High Plains will encourage a severe threat in this region as well. ...Southern Plains... Some cloud cover, along with widely scattered showers and thunderstorms, may be in place across portions of the southern Plains into the Ozarks by Sunday morning. As such, there are some uncertainties regarding how these initial conditions will impact downstream convective evolution. Nonetheless, guidance consensus suggests that surface temperatures will warm ahead of the front into the 90s F, with 70 F dewpoints, yielding 2500-3500 J/kg MLCAPE amid waning inhibition. This will support thunderstorm initiation by mid to late afternoon. Given mediocre vertical shear profiles, storms should quickly merge and become outflow dominant. However, given the potential for strong buoyancy, a short-lived cold-pool-driven MCS may develop, accompanied by a focused severe gust threat in central/eastern OK. ...Portions of MO into the OH Valley and central Appalachians... Isolated to widely scattered thunderstorm development is likely all along the cold front and periphery of the decaying upper ridge, from the Ozarks to the central Appalachians, during the afternoon given boundary-layer destabilization. The convergence of upper 60s F dewpoints along the front will boost MLCAPE to over 2000 J/kg. A few of the stronger multicellular complexes may produce a couple instances of severe wind/hail, though the severe threat should be limited to some degree given mainly 6 C/km mid-level lapse rates and mediocre vertical wind shear. ...Portions of eastern Colorado... Along the western flank of the cold front, upslope flow into eastern Colorado during the afternoon, will encourage scattered thunderstorm development. Notable veering flow above the boundary layer, along with increasing westerly flow through the remainder of the troposphere, will result in elongated hodographs and 40-50 kts of effective bulk shear. A few of the stronger storms should become supercellular. Given 7-8 C/km mid-level lapse rates, supercells may be accompanied by both severe wind and hail. ..Squitieri.. 09/19/2026 $$ |
Convective Outlook Day 3
SPC Day 3 Outlook Discussion
ACUS03 KWNS 190717 SWODY3 SPC AC 190715 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0215 AM CDT Sat Sep 19 2026 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE TENNESSEE VALLEY INTO THE SOUTHERN AND CENTRAL APPALACHIANS... ...SUMMARY... Isolated severe gusts may accompany the stronger storms over parts of the southern and central Appalachians on Monday. ...Synopsis... Mainly zonal mid-level flow, with embedded impulses, will characterize the upper air pattern east of the Rockies, with a mid-level trough slowly progressing across the Southwest on Monday. Eastern portions of a diffuse cold front will linger over portions of the eastern TN Valley into the central Appalachians Monday afternoon, supporting scattered thunderstorm development. Given upper 60s F dewpoints contributing to 1500+ J/kg of tall and thin MLCAPE, a few wet downbursts capable of producing damaging gusts may occur with the stronger storms. ..Squitieri.. 09/19/2026 $$ |
Convective Outlook Day 4-8
SPC Day 4-8 Outlook Discussion
ACUS48 KWNS 180822 SWOD48 SPC AC 180820 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0320 AM CDT Fri Sep 18 2026 Valid 211200Z - 261200Z ...DISCUSSION... Initially zonal mid-level flow, with embedded low-amplitude impulses traversing the central CONUS early next week, will give way to gradual amplification of an upper ridge over the central U.S. The best chance for any severe thunderstorms will be on Day 4/Monday across the TN Valley, where a surface cold front, preceded by rich low-level moisture, will be slow to clear the region. Thereafter, drier low-level conditions will prevail across much of the central and eastern CONUS, with surface high pressure poised to settle over much of the U.S. between the MS River and the Appalachians, limiting the severe threat. ..Squitieri.. 09/18/2026
Convective Weather Outlook Legend Data
- TSTMÂ (light green) – General or non-severe thunderstorms – Delineates, to the right of a line, where a 10% or greater probability of thunderstorms is forecast during the valid period.
- 1-MRGL (dark green) – Marginal risk – An area of severe storms of either limited organization and longevity, or very low coverage and marginal intensity.
- 2-SLGT (yellow) – Slight risk – An area of organized severe storms, which is not widespread in coverage with varying levels of intensity.
- 3-ENHÂ (orange) – Enhanced risk – An area of greater (relative to Slight risk) severe storm coverage with varying levels of intensity.
- 4-MDT (red) – Moderate risk – An area where widespread severe weather with several tornadoes and/or numerous severe thunderstorms is likely, some of which should be intense. This risk is usually reserved for days with several supercells producing intense tornadoes and/or very large hail. Or an intense squall line with widespread damaging winds.
- 5-HIGH (magenta) – High risk – An area where a severe weather outbreak is expected from either numerous intense and long-tracked tornadoes. Also, a long-lived derecho-producing thunderstorm complex that produces hurricane-force wind gusts and widespread damage. This risk is reserved for when high confidence exists in widespread coverage of severe weather with embedded instances of extreme severe. (i.e., violent tornadoes or very damaging convective wind events).
This data is courtesy from the Storm Prediction Center