Put some prefilter material over the honeycomb - it'll allow airflow and block rain. Engine compartment vents on jetski's have been using this method for years. Never had a drop of water in mine.
https://www.denniskirk.com/pre-filter-sheets.p305420.prd/305421.sku?_requestid=3198264
Commonly used on snowmobiles too.
That's a good idea. Do you think it would stay in place if you just cut it oversized and tuck it under the hood blanket? Also, what happens to the water? Would it just puddle on the upper side of the vents?