A typhoon approaches in a row.

You can't have a row of anything if there's only one. But even if you mean that you are expecting multiple typhoons, you wouldn't normally use 'in a row' with something like typhoons. It's not impossible -- you could say 'Japan was hit by 4 typhoons in a row', but I wouldn't use that expression about the future. If you mean that 'Japan is about to be hit by multiple typhoons, one after another.'

I heared that the greatest typhoon ever recorded is comingon its way.

The reason whycause of theis powerful typhoon forms isis the rising water temperature around Japan.

I hope no one will be damaginjured.

Damage is usually not used for beings, even animals. There are exceptions, like saying someone had 'heart damage' after a heart attack, but generally you would use the word 'injure' for beings.

A typhoon approaches in a row, right after the last one.

I understand what you meant by the sentence, but "in a row" would go with a plural noun, like "Typhoons are approaching in a row." But even then this phrase is usually used to talk about more specific numbers of something, like: "Three/Several typhoons occurred in a row."

One way to change the sentence that I think fits your meaning better is: "Typhoons are approaching one after another."

I heared that the greatest typhoon ever recorded is coming.

"largest" might fit better than "greatest" if you are talking specifically about size.

The reason why the powerful typhoon forms ed is the rising water temperature around Japan.

Or: "The powerful typhoon formed because of rising water temperatures around Japan."

I hope no one will be damaginjured.

"damaged" when meant in a physical way is usually used when talking about objects rather than people. "injured" probably works better in this context.