certain places where the virus is more likely to cause a rapid spread. Currently it's in probably every nation on earth, but where is really going to take hold? NYC is a prime spot for that based on the amount of travel, transportation, population per square mile. It's eight times larger than most cities in the US. It's just going to have more cases, even though let's say SLC has the same virus at the same time it's just going to spread slower, naturally flattening the curve. Less people, less public transportation, etc...
I am not of the opinion that SLC is weeks behind NYC. I think we are all on the same timeline, and the virus is just going to have more impact on certain areas based on geography, climate, density, population size. That's my take. If I'm wrong I'm wrong. But I think every US city will peak by early to mid April.