It is a fact that a number of regional airports, mainly - or, in the past, exclusively - staffed by "home grown" people develop some strange habits, but I am surprised that the originator of this thread has never heard of Meteorological Warnings. That said, it does, at first sight, seem a little unnecessary that reference is made to them on the ATIS, the function of which is to present immediately pertinent information, though I take Spitoon's point.
However - and this applies to a number of threads started on pprune - instead of agitating on a public forum, which results in a lot of "duff gen", why not write - yes, write - and in a slightly more formal, restrained manner to the Manager, ATS and get a response from the horse's mouth. Communication by e-mail is a little less than impressive if the topic requires a serious and formal response and if it was addressed to ATC generally, it might well have found its way to File 13! I think you will find MATS Bristol to be extremely competent, knowledgeable and enthusiastic that the unit should provide the best possible service.