For Meteobridge sites, the upload of conditions (including wind-speed/direction) are done via the conds.php on your website.
I just watched the wind direction icon/value change with several updates while the value for wind-speed remained the same.
The wind speed is updated (in ajaxMBwx.js) by
var wind = convertWind(realtime[5]);
and direction by
var val = windDir(realtime[7]);
from the MBrealtime.txt (fields 6 and 8, starting count at 1).
MBrealtime.txt uses
5 wspeed [wind0avgwind-act]
6 wlatest [wind0wind-act]
7 bearing [wind0dir-act]
for the wind, so to get the 'instant' wind (instead of the average windspeed), you can change ajaxMBwx.js
var wind = convertWind(realtime[5]);
to
var wind = convertWind(realtime[6]);
to get the current (non averaged) windspeed.