The Present Temporary Tense
I am writing.
This is used to describe actions taking place at the present moment, which we regard as temporary.
[that is, only continued for a time.]
The sun is rising.
Compare the following:
(i) The sun rises in the East. [habitually]
The sun is rising in the East. [at this moment, and soon its rising will be over]
(ii) Monica plays badminton well. [habitually]
Monica is playing well now.
[at this moment she is playing well, perhaps she will play badly soon]