Stop using convoluted bracketed constructions to tell your reader about opposites in your scientific writing.
For example, writing:
The first and second models overestimate (underestimate) precipitation in spring (summer).
is confusing. The reader still has to read the words enclosed in parentheses: in her head she hears the words “underestimate precipitation in spring” – or at least this is what I hear. This wasn’t your intention, right?
I instead advocate the use of an elegant semicolon construction:
The first and second models overestimate precipitation in spring; though they underestimate it in summer.
Not only are the words now in the right order, but your correct use of a semicolon (to separate two phrases that could form a sentence on their own) has emphasized their opposition. Just like Winston Churchill did here.