Kari
Like you said it is a proposal.   God uses the day to year principal throughout scripture. If FOT is anything I had looked for a 40 day warning.  I saw none.  The flood however is a type of the sudden destruction that is coming.  THere was no 40 day warning that we know of.  THe judgement itself was the 40 day warning-it rained 40 days and nights.  IF that principle is used by God the destruction coming, we would be gone and then a 40 day period starts.
 
thanks for your reply
 
will s