the wedding-day was set for the first of January ,1841. that was only six months away,
the wedding-day was set for the first of January ,1841. that was only six months away,but many a storm was to brew and blow before then
here,what does "but many"mean?it means "generally",doesn't it?

Question

the wedding-day was set for the first of January ,1841. that was only six months away,
the wedding-day was set for the first of January ,1841. that was only six months away,but many a storm was to brew and blow before then
here,what does "but many"mean?it means "generally",doesn't it?

Answer

"Many a storm" can mean many trials, hardships, setbacks, etc. not just literally a storm. So, when they said "...but many a storm was to brew and blow before then," it means that many problems were going to happen before the event (in this case, the wedding).

Answer

Many a storm = lots of storms, plenty of storms. Equally you can have "many a man" = many a man has tried and failed...

It's a little bit archaic, but still in use.