Why Sandy could be worse - and possibly not a hurricane

Sandy is expected to be unlike most hurricanes, and some on Twitter and Facebook have been critical of the National Hurricane Center for not issuing hurricane watches and warnings north of the North Carolina-Virginia border.

Temperature is the difference, according to the hurricane center.

Sandy is forecast to move to a position approximately 225 miles east of Cape Hatteras, N.C., by 2 a.m. Monday, according to the Connecticut Department of Emergency Services and Public Protection. With the storm is about 2,000 miles wide, Connecticut will already be feeling its force at that point.

"Sandy is then forecast to intensify and grow in size as the storm interacts with an approaching winter type storm system," according to the state. Sandy is forecast to move northwest to a position near the southern coast of New Jersey by 2 a.m. Tuesday.

Sandy is expected to be a large and dangerous hybrid when the storm arrives here Sunday night and Monday — the Frankenstorm many have been talking about. State officials warn that hybrid storms do not act like hurricanes and do not weaken over cold waters. Sandy is forecast to move slowly and impact our area for up to 36 hours with very strong winds, finally departing our area Wednesday morning.

The National Weather Service has issued High Wind Watches for the potential of strong winds sustained at 40-60 mph and gusting to 60-80 mph along the coast and in the higher elevations at times.

"This storm's heavy rain and winds, combined with the high tide, has the potential for a big impact on the entire state," Gov. Dannel P. Malloy said. "It's specifically drawing increased concern because of the forecasted duration, which could last up to 36 hours – longer than what we are used to in Connecticut. Please take this as seriously as we are taking it."

On its Facebook page, facebook.com/US.NOAA.NationalHurricaneCenter.gov , the National Hurrican Center wrote that its advisories are only for "tropical" storms.

"The National Hurricane Center issues advisories, forecasts, and warnings on tropical cyclones — the generic term for hurricanes, tropical storms, and tropical depressions. Sometime prior to making landfall, Hurricane Sandy is expected to lose its characteristics as a tropical cyclone and take on the structure of a wintertime low-pressure area. Because the National Hurricane Center only issues advisories on tropical cyclones, there will be changes in the flow of information coming out of the NWS when this transition occurs," according to the post.

The primary difference between a tropical cyclone and a wintertime cyclone is the energy source, according to NOAA.

"Tropical cyclones extract heat from the ocean and grow by releasing that heat in the atmosphere near the storm center. Wintertime cyclones (also called extratropical or frontal lows), on the other hand, get most of their energy from temperature contrasts in the atmosphere, and this energy usually gets distributed over larger areas. Because of these differences, tropical cyclones tend to have more compact wind fields, tend to be more symmetric, and have a well-defined inner core of strong winds. Wintertime lows have strong temperature contrasts or fronts attached to them, have a broader wind field, and more complex distributions of rain or snow," according to the Facebook post.

"Once Sandy loses its tropical cyclone status it will be known as 'Post-tropical Cyclone Sandy' in NWS products. Some aspects of this transition are already occurring, and NWS forecasts of storm impacts are based on this expected evolution. Regardless of when this transition formally occurs, Sandy is expected to bring significant wind, surge, rainfall and inland flooding hazards over an extremely large area, and snowfall to more limited areas."

The Hurricane Center wrote that by using non-tropical warnings for northern areas, "we avoid or minimize the significant confusion that could occur if the warning suite changed from tropical to non-tropical in the middle of the event."

Once Sandy becomes "non-tropical," the National Weather Service and not the National Hurricane Center will provide information.

However, if it remains "tropical," then the National Hurricane Center would issue advisories.