What is already known:
What this study adds:
As of today, extended range forecasts cannot be made on a consistent day to day basis. The ability of forecasters to predict severe weather beyond a three day lead time is limited. If it is made possible for forecasters to make reliable and consistent extended range forecasts, then the safety of the public will be enhanced by severe weather warnings several days in advance.
In order to potentially give forecasters a new tool in assisting with extended range forecasting of severe weather, the Climate Forecast System Version 2 (CFSv2) and its forecasts are being examined and compared with the Storm Prediction Center (SPC) Day 4–8 forecasts and also compared with actual reported events.
Granted that there are days without severe weather, few of SPC Day 4–8 Severe Weather Outlooks have actual forecasts. The CFSv2 has shown an ability to reliably forecast severe (or lack of severe) weather with a day four lead time and moderate reliability at day five. Although the CFSv2’s capability to forecast reliably beyond day five is, to some degree, limited, in this paper it is shown that the CFSv2 does have potential as an extended range forecasting tool.