Regional ensemble time-series images for severe-weather environmental parameters. Select a parameter and region to load the corresponding production graphic.
These products diagnose forecast environments favorable for severe weather. They are not storm reports, warnings, watches, or official SPC/NWS outlooks. Use them as situational-awareness guidance and consult SPC and local NWS offices for official forecasts.
The supercell composite parameter is a multi-variable index used to determine how conditionally favorable the environment is for supercell development. It considers the levels of instability, shear, and helicity produced by the forecast model. The tools below show a seasonally-standardized sum of daily SCP. Positive values exceeding 1 standard deviation suggest unusually high values for that time of year. This can be used to assess relative risk.
The significant tornado parameter is a multi-variable index used to determine how conditionally favorable the environment is for significant tornado development. It considers the levels of instability, cloud base height, capping, shear, and helicity produced by the forecast model. The tools below show a seasonally-standardized sum of daily STP. Positive values exceeding 1 standard deviation suggest unusually high values for that time of year. This can be used to assess relative risk.
The significant hail parameter is a multi-variable index used to determine how conditionally favorable the environment is for significant hail development. It considers the levels of instability, mid-level lapse rates, water vapor content, and shear produced by the forecast model. The tools below show a seasonally-standardized sum of daily STP. Positive values exceeding 1 standard deviation suggest unusually high values for that time of year. This can be used to assess relative risk.
The image source is constructed from https://svrimg.niu.edu/heatmap/data/timeseries/{parameter}/{region}.jpg.