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 291950 SWODY1 SPC AC 291949 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Sat Aug 29 2026 Valid 292000Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEVERE THUNDERSTORMS FROM EASTERN NEVADA ACROSS NORTHERN UTAH INTO FAR SOUTHWEST WYOMING... ...SUMMARY... Widely scattered strong to severe storms are expected across parts of the northern Great Basin, northern/central Rockies, and northern Plains. Severe wind gusts are the main threat. ...20z Update... No changes are needed to the current D1 Convective Outlook. See MCDs #2167, #2168, and the previous discussion below for more information. ..Thornton.. 08/29/2026 .PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Aug 29 2026/ ...Great Basin through the central Rockies... Enhanced mid-level southwesterly flow aloft exists between the upper ridging centered over the southern High Plains and a shortwave trough moving through the Pacific Northwest. 12Z SLC sounding sampled this enhanced flow well, reporting a belt of 50-55 kt wind around 600 to 500 mb. This sounding also sampled the increased mid-level moisture within this belt of stronger flow, resulting precipitable water over 1.1". Modest heating of this airmass is expected to foster moderate buoyancy, although the widespread cloudiness could keep the airmass from fully destabilizing. Most RAP soundings across the region maintain lingering convective inhibition from UT into southern WY. Even so, the combination of modest buoyancy, mid-level moisture, and ascent attendant to a low-amplitude shortwave trough progressing through the region will support scattered to numerous thunderstorms from eastern NV across UT into northwest CO/southern WY. Some isolated hail is possible with the strongest cores (which could briefly acquire supercellular characteristics), but the primary severe risk is strong to severe wind gusts. Highest severe coverage is still expected from east-central NV into northern UT where the greatest afternoon buoyancy is forecast. ...Northeast CO/eastern WY/NE Panhandle into the western/central Dakotas... High-based showers and thunderstorms along the leading edge of the strongest ascent attendant to the shortwave trough moving through the Great Basin and central Rockies should emerge into a diurnally destabilized and moderately buoyant airmass from northeast CO into eastern WY and the NE Panhandle during the late afternoon/early evening. This could result in reintensification, and a risk for both large hail and damaging gusts across the region throughout the evening. Most of the guidance was overly aggressive with destabilization and buoyancy across this region yesterday, and there is some concern that cloud cover could again limit heating. That being said, there is a pocket of greater low-level moisture across SD and the region is currently under widely scattered cloud cover. Enhanced westerly flow atop low-level easterlies will support at least moderate deep-layer shear, so any updrafts that can mature should be able to organize, with an attendant risk for large hail and damaging gusts. ...AZ... 12Z PHX sounding sampled moderate mid-level moisture atop warm and dry low levels. Scattered thunderstorm development is anticipated across much of the region. Vertical shear is weak and a largely disorganized storm mode is anticipated. Still, given the high storm bases and steep low-level lapse rates, isolated strong to severe gusts are possible this afternoon and evening. $$ |
Convective Outlook Day 2
SPC Day 2 Outlook Discussion
ACUS02 KWNS 291725 SWODY2 SPC AC 291724 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 PM CDT Sat Aug 29 2026 Valid 301200Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE NORTHERN PLAINS... ...SUMMARY... At least isolated severe storms, accompanied by mainly a severe wind and hail threat, are possible across portions of the northern Plains on Sunday. ...Discussion... A shortwave trough will move across the northern Rockies on Sunday, with upper low deepening over SK. This trough will bring increasing wind fields and cooling aloft across the northern High Plains and Dakotas late in the day and overnight. At the surface, low pressure will develop during the afternoon from near the MT/ND border southward into western SD ahead of a cold front, which will move across the Dakotas overnight. A warm front will also extend eastward from SD into southern MN, WI and Lower MI, where mid to upper 60s F dewpoints are likely to exist. Isolated elevated storms may be ongoing Sunday morning from parts of southern MN into IA, WI and Lower MI, though models are quite variable. Winds at 850 mb will be veered to west/southwest, and height rises will occur throughout the day. As such, any activity that does develop should remain disorganized, with low severe chances if any. During the afternoon, storms are most likely to develop along the cold front from eastern MT into northeast WY, northwest SD, and into much of ND. These may be mixed mode storms, as winds below 500 mb will remain relatively weak, though high level winds will be stronger. Scattered severe gusts or hail above 1.00" appear likely through the night as activity pushes across ND and into northern MN. Farther south, scattered strong to severe wind gusts may occur over the central High Plains as high based convection moves off the high terrain of CO/WY, aided by 30-40 kt midlevel westerlies. Steep low-level lapse rates/deep mixed layers may support localized wind potential. ..Jewell.. 08/29/2026 $$ |
Convective Outlook Day 3
SPC Day 3 Outlook Discussion
ACUS03 KWNS 291935 SWODY3 SPC AC 291934 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Sat Aug 29 2026 Valid 311200Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL HIGH PLAINS TO PARTS OF THE CORN BELT... ...SUMMARY... Isolated severe thunderstorms, accompanied by wind and hail, are possible Monday afternoon from the central High Plains toward parts of the Corn Belt. ...Discussion... On Monday, a shortwave trough will lift northeastward out of the Northern Plains, with an upper high over the Mid MS/Lower OH Valleys. To the west, an upper low will drop southward off the West Coast, with increasing southwest flow aloft from CA into the Great Basin late. A leading wave is also forecast to develop over the central Rockies, moving from CO into NE overnight. At the surface, a quasi-stationary boundary will extend from NE/SD into southern MN/WI, where 60s to 70s F dewpoints will exist. Conditionally, this region could support a severe risk. However, the departing upper wave combined veering and weakening low-level winds suggest minimal storm coverage for most of the period. Some forecast soundings also indicate shallow boundary layer moisture. However, isolated storms cannot be ruled out both during the day and overnight within this moist zone, therefore will maintain low severe probabilities. Scattered strong to severe storms may also occur over the Central High Plains, where a lee trough will develop and where a developing midlevel wave is forecast. Strong heating as well as 50s to near 60 F dewpoints will support scattered late afternoon storms from eastern CO/southeast WY, spreading northeast into NE. A few severe gusts or marginal hail will be possible. ..Jewell.. 08/29/2026 $$ |
Convective Outlook Day 4-8
SPC Day 4-8 Outlook Discussion
ACUS48 KWNS 290857 SWOD48 SPC AC 290855 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CDT Sat Aug 29 2026 Valid 011200Z - 061200Z ...DISCUSSION... Medium range guidance consensus depicts a persistent ridge fortified across the central CONUS through the Days 4-8 (Tuesday-Saturday) period. Multiple mid-level shortwave troughs and smaller scale impulses will pivot around the broader upper ridge and traverse the Pacific Northwest to northern Plains, Great Lakes, and Northeast through the week. The best chance for rounds of organized strong to severe thunderstorms will be with impulses overspreading a moist boundary layer from the Upper MS Valley to the southern New England/Mid-Atlantic regions. Details regarding the timing and placement of some of these impulses varies among medium-range guidance, rendering predictability too low for several potential severe scenarios. ...Days 4-7 (Tuesday-Friday) - Northeast/Mid-Atlantic... The Northeast to Mid-Atlantic will experience the east-northeast periphery of the aforementioned upper ridge, with multiple impulses expected to overspread the region through the middle of the week. At least isolated to scattered severe thunderstorms are expected each day Tuesday-Friday. At the moment, medium range guidance consensus shows the strongest signal in a mid-level impulse impinging on southern New England and the Mid-Atlantic on Day 5/Wednesday, where severe probabilities have been maintained. Guidance also depicts these same regions to have adequate vertical wind shear and instability Tuesday and Thursday, perhaps even extending into Day 7/Friday. Like Wednesday, several members of medium range ML/AI generated guidance also has severe probabilities over these regions Days 4-7. Unlike Wednesday though, deterministic medium range guidance varies in place and time of the more subtle impulses expected to support severe weather over the Northeast. It is acknowledged that severe probabilities will likely be needed in the future. However, probabilities have been withheld outside of Wednesday out of prudence given the degree of changes in forecast details expected in the coming days. ..Squitieri.. 08/29/2026
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