Naming tropical storms has been common practice for decades, in no small part because it helps meteorologists raise awareness and helps the media and the public keep track. Popular culture might give other names to extraordinarily powerful or inconvenient storms - tropical or not - such as 1991’s “Perfect Storm," which had Hurricane Grace as one of its ingredients, and the 2010 “Snowmageddon.”

But rare is the storm that gets a name three days before it’s even formed.

This is the case with “Frankenstorm,” the name that news and social media gave to a superstorm that could happen if Hurricane Sandy - churning Friday a couple hundred miles off Florida’s east coast - merges with a strong cold front from the west next week. Such a storm could sit over New England for days, making untold trouble for millions.

If you’re wondering where “Frankenstorm” came from: The name appears to have picked up steam after meteorologists noticed the National Weather Service’s Hydrometeorological Prediction Center’s extended forecast discussion page from Thursday afternoon.

In that discussion, a prediction center meteorologist wrote that the unusual merger of Hurricane Sandy and the cold front would happen around Wednesday - Halloween - "inviting perhaps a ghoulish nickname for the cyclone along the lines of 'Frankenstorm,' an allusion to Mary Shelley's gothic creature of synthesized elements."

CNN and other media outlets used the name to describe a storm that could cause serious misery for the Northeast. CNN later decided to stay away from "Frankenstorm," because of the storm's severity.

CNN meteorologist Rob Marciano explained why forecasters and reporters were tempted to use the "Frankenstorm" moniker.

"We want to name it because it's unlike anything we've seen meteorologically," he said. "At first, when nicknames were thrown out there, the meteorologists were having fun with it - it was interesting to us, and no one believed, frankly, that the models would continue this trend. Now it's gone from joking around and 'it won't happen' to, now, it looks like it will happen, and now we're in a more serious tone."

Sandy already has claimed nearly two dozen lives in the Caribbean, and meteorologists warn it packs the potential to slam the Northeastern United States as soon as Monday with powerful winds, pelting rain and cold temperatures.

"Forget about the category with this," said Marciano. "When you have trees with leaves on them still, this kind of wind and rain on top of that, you're talking about trees that are going to come down, power lines are going to be out and the coastal flooding situation is going to be huge."

CNN meteorologist Chad Meyers added, "This could be like the 'Perfect Storm' 21 years ago."

A combination of three weather systems produced the famed "Perfect Storm" in the north Atlantic over Halloween 1991 when moisture flung north by Hurricane Grace combined with a high pressure system and a cold front, according to the weather service.