Sandy could be a newsmaker ... even locally

Tropical Storm (soon-to-be Hurricane) Sandy is the talk of the meteorology message boards today, because some computer models predict it could become a historic East Coast storm.

And while we in the Charlotte area almost certainly won't even see a drop of rain from Sandy, it could have an impact on our weather for weeks to come.

On Wednesday morning, Sandy is a purely tropical system and is beginning to hammer Jamaica. It is expected to cross Jamaica and then make landfall in eastern Cuba, before moving across the eastern Bahamas later in the week.

That part of the storm's track is considered highly likely.

It's what happens afterwards that is generating talk (and predictions of a cataclysmic storm on the East Coast late this weekend and early next week).

Originally, the computer models predicted Sandy would curve northeast and out to sea, a danger only to fish and possibly Bermuda.  But the European model began predicting Tuesday that Sandy would push north-northeast, well off the U.S. coast of Florida, Georgia and the Carolinas, but then curve back toward the coast after passing the Outer Banks.

On Wednesday, some of the other computer models began picking up on the same trend.

There's another big player in the whole picture. A surge of cold air will push into the eastern United States later this week, fed by a large trough of low pressure. That system will have plenty of energy, and some of the computer models predict Sandy will absorb strength from the trough and intensify rapidly.

This is somewhat similar to the "Perfect Storm" -- the 1991 Halloween Nor'easter that did huge damage on the East Coast and got some of its strength from Hurricane Grace in the Atlantic.

There seem to be three possibilities here:

1. Out to sea.  Sandy swings northeast, out to sea, and doesn't bother anyone in the mainland United States.

2. Curve back to the coast.  Sandy curves back to the northwest and blasts into the U.S. coast, somewhere between Maryland and Maine. Some computer models show a storm of  up to Category 3 hurricane power.

But another theory holds that Sandy would lose some or much of its tropical characteristics and be a subtropical or post-tropical system.  That would still produce heavy damage on the coast, with huge waves, heavy rain and strong winds. But under that scenario, the winds would be spread across a much wider area than a hurricane but would not be as strong (maybe 60 to 80 mph).

New York City, Boston and Philadelphia would be targets of such a storm.

3. "Replacement" storm.  Another theory holds that Sandy might curve out to sea but leave a weakness in the atmosphere behind. That weakness would turn into a coastal low pressure system that would move up the coast. That system would get very strong, absorbing energy from the advancing trough, and bring big waves, heavy rain, strong winds and even heavy, wet inland snow to the East.

FOR US?

Cold air is coming late in the weekend and will remain next week.  We'll almost certainly have our first frost Tuesday morning, and we'll be seeing daytime highs in the upper 50s and lower 60s, with nighttime lows in the 30s, for at least part of the week.

But a super-sized Sandy could affect our weather for weeks.  Sometimes these huge and powerful systems can help change the overall weather pattern in the Northern Hemisphere.  I saw some conjecture that Sandy could help create a Negative North Atlantic Oscillation. A negative NAO means cold weather will come spilling into the eastern United States for at least the first part of November, and possibly longer.

After several weeks of quiet weather, we certainly have something to talk about this week.