THE BLOG
10/27/2012 02:27 pm ET | Updated Dec 27, 2012

Frankenstorm: Fact and Fiction

There is plenty of media discussion related to the developing and dangerous storm system that's being called Frankenstorm. With so much information being generated from weather and non-weather sources, it's difficult to separate fact from fiction.

That's what I'll try to do here -- in a general sense, not intended as specific forecast information.

If you're in the potential path of the storm, then follow local sources of weather information extremely closely and take any necessary actions to best prepare yourself.

There has never been a storm like this.

False.

The storm, called a hybrid storm, will be a combination of a tropical system (Hurricane Sandy) and a non-tropical system (a storm that would produce a typical rain or snow storm). While we don't see this type of merger often, it does happen on occasion, especially in the fall when tropical waters are still warm enough to support tropical storms and hurricanes and the main storm track (which produces the non-tropical storms) is beginning to gear up for winter.

The so-called "Perfect Storm" of book and movie fame was such a storm. That storm (in 1991) never made a direct hit on the United States but still caused hundreds of millions of dollars in damage.

This will be the worst storm in history.

Possibly true, at least for some.

There are three weather factors that will make this storm so potent (compared to the Perfect Storm since that's a well-known example of an intense hybrid storm):

  • The strength and energy being added to "Frankenstorm" from Hurricane Sandy is much more intense than the tropical energy that was added to the Perfect Storm in 1991. The tropical energy is an extremely important factor in the intensity of the storm.
  • The strength of the non-tropical storm moving into Frankenstorm is also more intense than with the Perfect Storm.
  • Frankenstorm will make a direct landfall in a highly populated portion of the United States, which intensifies the danger to lives and property.

For these reasons, Frankenstorm has the potential to be the strongest storm in recorded weather history to affect the areas where it hits most directly. That fact cannot be emphasized enough.

What can be overplayed, though, (and therefore perceived as hype) is that the storm will not be the worst in history for everyone and that we don't have a complete history of weather, and those points can get lost during a media firestorm.

This is a rogue storm.

False.

Hybrid storms are sometimes called rogue storms, but this is a misnomer. Rogue means unpredictable. The best recent example might be Sarah Palin going "rogue" in the 2008 election.

Hybrid means something powered by more than one source, such as a hybrid car that is part electric and part gasoline.

The forecast details on Frankenstorm will be hard to pinpoint, but the storm itself is not some unpredictable beast with a mind of its own as the word rogue might insinuate.

It's a "weak" hurricane, so storm surge and coastal flooding won't be so bad.

False!! False!! False!!

The storm surge, which is a temporary rise in the ocean level caused by a storm as it pushes water along in front of it, is the most deadly part of a hurricane. The surge is a reflection of the size the storm, the intensity of the wind, the direction of the wind, the shape of the coastline, etc.

This storm surge will be very dangerous this storm, especially from the center of the storm northward, and a significant surge will extend very far to the north of the center because of its size. In addition to the surge, wind waves on top of the surge will cause additional flooding and structural damage.

Coastal residents who are alerted of the need to evacuate need to heed the warnings.

The storm is going to bring snow, as well as wind and rain.

Technically true, but false for most.

Many of the reports of the storm in the media are muddled and include references to storm surge, wind, flooding rain, and snow without giving precise details about what part of the storm will affect what regions. In addition, people sometimes listen to forecast information with half an ear, so even when the information is properly conveyed, the overall perception becomes jumbled.

For instance, I've read comments on Web sites where people in Washington, D.C., are wondering whether they'll get rain or snow. Snow is not a concern for Washington, D.C.

So, for that reason, I'm going to say that the emphasis on the snow part of the storm is being overplayed. A relatively small area has the potential to receive snow from Frankenstorm.

The caveat is that where the potential for heavy snow exists, mainly in the high elevations from West Virginia to southwestern Pennsylvania, it would be a major problem if it were to happen. With leaves still on some trees, the potential for downed power lines and tree limbs is high. But most areas will not see snow from Frankenstorm.

Frankenstorm will be just a dangerous even if Sandy is downgraded to a tropical storm tropical depression.

True.

Because of the nature of this hybrid storm, whether Sandy is a hurricane, a tropical storm, or tropical depression does not make a great deal of difference. That's because the energy from the tropical heat and moisture is roughly the same regardless of Sandy's current status, and that is a critical factor in the strength of Frankenstorm.

The storm will weaken after moving inland.

False.

Hurricanes and tropical storms derive their energy from the warm water and, therefore, typically quickly weaken once moving inland. This storm, however, since the energy will be added to that of the non-tropical portion of the storm, will maintain strength while moving inland.

Tropical-storm force and hurricane-force winds survive for a longer period of time and will extend much farther inland than with a typical hurricane. Some interior areas will experience hurricane conditions that have never experienced them before.

The flooding threat in the Northeast will be as extreme as it was with Irene.

False.

Flash flooding and urban flooding is a serious threat with nearly any tropical system, and that will certainly be the case with this hybrid storm, especially since the storm will not be quick to move out of the mid-Atlantic region and Northeast. However, the flooding risk along major rivers is not as great with Frankenstorm as it was with the remnants of Hurricane Irene in the summer of 2011.

Irene's rain fell on already water-logged areas, and the result was the worst river flooding in recorded weather history for many. The relatively dry time preceding Frankenstorm should prevent the intensity of river flooding; however, the threat of life-threatening flash flooding still exists.