It's snowing heavily

It's snowing heavily

Since this morning it has been snowing across a wide area of Japan. 
It took me extra 30 minutes to get to my office.
Yesterday, the weather forecast said the highest temperature, in the vicinity of around my office, would be 3 degrees celcius today.
As he said so Like it said, I feel it's so cool cold outside that I don't want to go out of leave my office.
But I have to go out for my lunch. I hope it stops snowing when before I go home.

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I hope it stops snowing before I go home

or

I hope it has already stopped snowing when I go home.

It's snowing heavily

Today it has been snowing in a wide area of Japan since this morning.
It took an extra 30 minutes to get to my office.
The weather forecast said yesterday that the highest temperature around my office today would be 3 celcius.
As he said so, I feel that it's so cool outside that I don't want to go out of my office.
But I have to goet out for my lunch. I hope it stops snowing when/before I go home.