nowcast

Short definition from Wiktionary

Verb

1. 1
   To predict the weather for a very short upcoming period (usually a few hours).
2. 2
   To estimate what is currently happening based on knowledge of how data is biased.

Noun

1. 1
   A weather forecast predicting the weather for a very short upcoming period, usually only a few hours.
2. 2
   An estimate made by nowcasting.