When Do The Weather Patterns upon LV-426 change?

From Prometheus to Alien - unless there are stories to still be told in-between until the events of Alien - how and why does the weather change upon the little planetoid from what seems like mild barren, stable-like weather to almost martian type global blizzards? True, in Alien we as the viewers may have just seen a particular storm that had brewed up coincidentally when the Nostromo had gone into orbit around the little world. But it could be that some natural or even artificial catastophe slightly 'knockedit' out of its original orbital trajectory and thus forced a change upon the planetoid through its weather systems. It cold be like Mars and have frequent weather systems that 'blow hot and cold' so to speak from time to time but in keeping with the shifting of the planetoids orbit idea makes me wonder if that has some crittical bearing upon the stories narrative. It makes me think of Star Trek II: The Wrath Of Khan where Khan states that He and the rest are actually on Seti Alpha Five. He confirms to the two researches he holds captive that Seti Alpha Six exploded six months after they were left there. The shockwave shifted the orbit of the Seti Alpha Five planet leaving 'it' and everything upon it laid wasted and barren. I just wonder if weather systems like the one that looks like it brews up from time to time occur all of the time on the little planetoid and what we see in Alien is just how a typical storm cell wold be on the night-side of the planet and its like this all the time from time to time though. O something BIG happens which potentially ROCKS this little world down to its core and that of the plot line as well! I hope its signifigant that something may occur that shifts the world off of its axis and thus would go a long way to explaining the such ahrsh conditions upon such a relatively tiny world.