Here are two different ideas about writing, since not all writers are the same:
First is the 1000 words a day idea, which I've seen other writers use extremely well. When I was at the Rockefeller Center in Bellagio, one colleague sat at her desk every morning after breakfast, and stayed there until the 1000 words were done. How long that took varied. But sometimes she was finished in the early afternoon, and then she took the afternoon off, and had more time for strolls along Lake Como than I did, with my less disciplined/more erratic approach to writing. If the 1000-words-a-day approach fits you as a writer, I highly recommend it.
So what's an alternative? An approach based on time and space, rather than quantity of words. Pick a time of day that is your writing time. Spend that time in a space that is reserved for writing. You go to your space at the designated time, and then all you can do is write. No phone, no email, nothing else. If you're at your office, put a "do not disturb/available after __ p.m." sign on your door. You might feel that you should spend 8 hours a day doing nothing but writing, but that is unrealistic (unrealistic for every day, as compared w/ days when the momentum is going, and you can't seem to stop). To really protect that time, it might need to be 2-3 hours. If you need to make a lot of progress in a short time, perhaps schedule two writing blocks during a day. But I think you'll find that if you actually spend 2-3 solid hours writing every day, with no email and nothing but writing, you will have an article by the end of the summer. (The revision/reading/research go on at other times. It's easier to go back & forth between revisions and email than between writing and various distractions.)
I am a rather erratic writer: some days there are pages, other days if I end up with one really good sentence, that's all I can show for it. On those days I may write many paragraphs and then delete them in disgust. But luckily for me, projects seem to gather momentum, and then I get swept into the writing. I forget to stop for a meal, and will look up from the page at 2 a.m., wondering how it got to be so late. If you're that kind of writer, the problem is that you can't plan momentum (in the way that you can plan 1000 words a day). So you have to create conditions that might lead to it. A regular writing time & place might help you get there.
Good luck to all this summer!