Difference between 3hr fixes and 6hr fixes

[RL3AO]

Whats the difference? This current flight is doing three hour fixes but its doing the same thing as previous (six-hr fixes) flights. Whats the difference? and What exactly is a fix?

[pojo]

Whats the difference? This current flight is doing three hour fixes but its doing the same thing as previous (six-hr fixes) flights. Whats the difference? and What exactly is a fix?

the fix is when we mark the center of circulation within the window (hour before to 1/2 hour after) for example 18z ... can be fixed within 17z to 1830z... as long as the VDM time is within that window.

3hrlys occur when landfall is imminent to the US coastline.... usually 36-48hours out from landfall ... 6 hrlys occur when there is a threat to US coastline...