You have a good visual piece going here, but I recommend reading over the piece (preferably out loud) and giving it some good editing yourself before you post it. This will help you out with working out your trailing off problem, as well as any grammatical/story errors spell check won't catch.
When you describe the clouds, I would suggest a more organic description outside of a computer. While I see what you were trying to get across, using a computer program for descriptive imagery is boring. I suggest using something akin to "it looked as if bits of the blue sky were pulled away to reveal a white wall." In relation to this, you have a good opportunity to describe the transition of the time of day from evening to night; I wouldn't miss the chance to develop this.
In general, I would work on your metaphors and similies in regards to description of the landscape. Your description of the cityscape and its surroundings starts off well, but falls flat due to a lack of imagery. The description of the lakes are a good part of this; add more.
However, you do well with the paragraph beginning with "tiring fast." The description of the sweat is done well because the reader gets a clear picture in his head. It also helps portray the man's physical exhaustion.
Hopes this helps; don't hesitate to message me if you want any more feedback