The act of having a "wish" or "desire" for a weather event to intensify. In hurricanes, it is a wish for the hurricane to intensify or increase it's stats.
Wishcasting:
HurricaneHarvey will get upgraded to a Category 5!
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).