be going to: I'm going to visit my cousins in Leeds over the coming weekend.
future progressive: I'll be visiting my cousins in Leeds over the coming weekend.
present progressive: I'm visiting my cousins in Leeds over this coming weekend.
We can use all three of these forms to talk about planned future actions, Timur, and there is not a great deal of difference between them.
I'm visiting my cousins in Leeds over this coming weekend.
The present progressive is most used for arrangements in the near future, usually when time and place have already been decided:
I'll be visiting my cousins in Leeds over this coming weekend.
The future progressive is also used to refer to planned future events. We often use it to make polite enquiries about people's plans:
What are you doing after the lesson?
I'm meeting Ronnie for a coffee.
Where are you meeting him?.
I'm meeting him under the clock at Victoria Station.
What are you doing tonight?
I'm staying in. I've got loads of emails to reply to.
We can also use the future progressive for making predictions about what will happen over a period of time in the future:
Will you be staying in tonight?
No I won't. I'm going out. I have to see Brian to plan the trip to Greece.
Will you be staying in Bristol for very long?
No, just for a few days. Then we're moving on to Cardiff.
Note that while we can use future progressive and be going to future for making predictions, we cannot use the present progressive in this way:
This time next year I shall be working for Gabriel in Brazil.
While you're revising for your exams, I shall be relaxing on a beach but I will be thinking of you!
I'm going to visit my cousins in Leeds over this coming weekend.
Look at those dark clouds. It will be raining here very soon
Look at those dark clouds. It's going to rain here before long.
(BUT NOT: Look at those dark clouds. It's raining here before long.)
If we put it this way, we are focusing our attention on intentions rather than on previous arrangements. Thus, be going to is used to talk about both predictions and intentions:
I'm to visit my cousins in Leeds over this coming weekend.
They're going to get married some time next year. ~ When? ~ They're planning to get married in the summer, I think, but there's no date yet.
Have you noticed that Irene seems to be putting on weight? Haven't you heard? She's going to have a baby.
They're going to win this match. They're three - nil up and there's only ten minutes left to play.
Note that we use the be to future to refer to arrangements that have been made on our behalf, often of an official nature:
The Prince is to visit three inner-city schools and to open the new wing of the hospital before he takes his Easter holiday.
Sven-Goran Eriksson is to manage the England team until 2008. He signed a new contract yesterday.