Consistent colors leading up to the forecast period correlate with good forecasts and lead times.
These patterns typically do not show up until about 7 days before the event.
The y-axis is the date of the model run, the x-axis is the forecast target date.
The rightmost day has the most chiclets because all of the model runs from the dates on the y-axis produced a forecast for that date.
Storm Prediction Center Definition: SCP
A higher number corresponds to higher values of three key ingredients for supercells: 1) directional shear, 2) speed shear, and 3) instability.
Storm Prediction Center Definition: STP
A higher number corresponds to higher values of four key ingredients for significant (EF2+) tornadoes: 1) directional shear, 2) speed shear, 3) instability, and 4) low cloud bases.
The values above represent the ensemble mean of daily (~6 a.m. to ~6 a.m.) sums of SCP and STP values for grids in the United States.
Larger numbers (darker colors) represent larger areal coverage non-zero SCP values.
Smaller numbers (lighter colors) represent smaller areal coverage of non-zero SCP values.
A lower number for a day does not mean zero risk, as the risk could be regional or localized in nature.