The NCWF is an automatically generated depiction of current convection and extrapolated significant current convection. It is a supplement to, but does
not substitute the report and forecast information contained in Convective SIGMETs. Convection, particularly significant convection, is typically associated with thunderstorm activity.
The National Weather Service Aviation Weather Center (AWC) updates the NCWF based on input from the Next Generation Weather Radar (NEXRAD) and cloud-to-ground lightning data.
The NCWF is most accurate for long-lived mature multi-storm systems such as organized line storms. NCWF does not forecast initiation, growth or decay of thunderstorms. Therefore, NCWF tends to under-warn on new and growing storms and over-warn on dying storms. Forecast positions of small, isolated or weaker thunderstorms are not displayed.
The NCWF area of coverage is limited to the 48 contiguous states.