Why the big change in the models?

There has been alot of talk on a potentially near-historic storm affecting many in the east,however as of thursday afternoon most if not all of the global models went drasticaly east and weaker.The models yesterday still showed a more easterly trend taking the storm of the east coast giving the I-95 cities a major snowstorm.So to the question now Why did the models change so big?. Well the answer is the jet streams.When the models wre showing a negitively-tilted deep storm slamming southern ontario with heavy snow that was the result of the northern branch and the southern branch of the jet stream phasing together,however now it is looking likely that we are going to see a less phased storm meaning that it will track east of the apps or near or along the east coast.I am not ready to throw in the towel just yet I'll give it till sunday night.If anything changes YWM and I will keep you posted.