The modern W/S systems have 2 modes, Alert or Caution and Warning. In the first case, the EGPWS will detect an increasing headwind or updraft, thru the EGPWS inputs that it uses for all modes, VSI, ASI, RA, Barometric ALT, Gear and Flap position and aircraft position to the EGPWS database, which has GPS input to it as well. This will give an amber alert and not usually escape guidance, as its not really required with an alert, more to let you know whats happening, if you don't feel it thru your arse as mentioned!
The warning comes with a red visual warning, audio alerts, and Flight director escape guidance. The older GPWS systems should give the same warning, but no cautions/alerts. However, I can't quite remember when I last used that system. Getting older so had to "download" that info so I could remember all the new items!
Kenny, I stand to be corrected, but I believe the WX radar has nothing to do with it as it only "sees" precipitaion and converts that to rainfall rates thru color. I don't know of any radars that can see wind direction and velocitys.
Slash, looking at this graph in our PRM, the rates you've mentioned look to be the same, so perhaps its an accepted industry standard.
Nosey