forecast vs portent

forecast

noun
  • exacta 

  • An estimation of a future condition. 

  • A prediction of the weather. 

verb
  • To estimate how something will be in the future. 

  • To foreshadow; to suggest something in advance. 

portent

noun
  • A portending; significance 

  • Something regarded as portentous; a marvel; prodigy. 

  • Something that portends an event about to occur, especially an unfortunate or evil event; an omen. 

How often have the words forecast and portent occurred in a corpus of books? (source: Google Ngram Viewer )