English pronunciation / spelling guides appear to state that the letter/grapheme "a" is pronounced either as the "short a" with IPA symbol /æ/, as in "mat" or the "long a" with IPA symbol /eɪ/, as in "baby."
However, apparently there exist multiple words where all references I checked provide the spelling of "short e" with IPA symbol /e/ or /ɛ/ which I take as a variation in the IPA transcription not in the underlying pronunciation.
What I'm unable to come up with or find a reference for is when will the grapheme "a" be pronounced as /e/ (or /ɛ/) instead of the short "a" /æ/ that the typical rules would predict?
Examples of words that have "a" transcribed as /e/: - temporary - nefarious - compare - share - dare - subsidiary (many more have two alternative pronunciations listed, one with /æ/ and one with /e/)
I recognize that all these examples include the sequence "ar" but I do not know if this is only because I was searching for this sequence in a corpus (based on the original example of "nefarious") or because there exist no other cases.
Actually, I find that my most trusted reference "The ABC's and all their tricks" by Margaret M. Bishop is including some of these words in the group of "-arr-" as in "carry", which my dictionaries transcribe as /ˈkæri/. This mixes two different pronunciations under the same rule. Is there no "rule" to help predicting the /æ/ or /e/ realization?