Thursday, October 25, 2012

Will Sandy Be A Repeat of the 1991 'Perfect Storm'?

Many in the weather world are asking or being asked if Sandy will turn out to be a repeat of the 1991 Perfect Storm that brought chaos to the entire Northeast. Let's see what similarities they have.

SIMILARITY: Both events involve merging storms.
Both the 1991 Perfect Storm and Hurricane Sandy will/did involve the merging of storm systems. Sandy looks like it will merge with a system that is currently bringing cold air to the Midwest and Plains. This merging will bring Sandy inland.

DIFFERENCE: The number of merging storms is different.
Sandy will merge with one other system. The 1991 Perfect Storm managed to hoard two other systems for itself. In other words, Sandy will have less energy to deal with.

SIMILARITY: Both of these events will have tropical origins.
Sandy is currently a Category 2 hurricane, and will still be tropical before it merges with the other system. Hurricane Grace in 1991 was also a Category 2 hurricane in the northern Atlantic that eventually merged with two other systems.

DIFFERENCE: Hurricane Sandy has much lower pressure.
Hurricane Sandy has pressures as low as a major hurricane (Category 3+), while Grace was a short-lived hurricane. Sandy is stronger, Grace was technically weaker.

SIMILARITY: Both occurred in October.
As eerie as this is, yes, both Grace and Sandy are/were active in late October. What makes this story even eerier is how Sandy should make its landfall on the Northeast on October 30- the same day in 1991 that Grace was absorbed by another system, when the Perfect Storm technically began.

DIFFERENCE: Sandy originated in the Caribbean.
There's a major difference here. Hurricane Sandy originated in the heart of the Caribbean, home to moisture as abundant as water in the Pacific Ocean. Hurricane Grace began in the ocean to the far east of Florida, in waters not nearly as favorable as Sandy.

In short, Sandy and Grace were entirely different, and will end up entirely different. While both tropical and post-tropical systems have their similarities, there's a reason why it was named the Perfect Storm- because it almost never happens. Sandy will be a close rival to the Perfect Storm's make-up, but effects and overall composure of the two are pretty far apart.

Andrew

3 comments:

Wally Gullang said...

Andrew I could use your professional opinion on hurricane Sandy. I have plan's for going to Portland, Maine on Monday the 29th and being there till the 3rd of November. Would you advise that I chnge my plan's ?

Andrew said...

Mike, you have been one of my longest followers. I know you want weather, and I don't want people like that to get to you. Don't worry about them- the more attention you give, the worse it gets. I can handle the spammers, you worry about the weather :-)

Anonymous said...

Wonder if the system in my area will bring very cold air to parts of the Mid-Atlantic states, I think it is a possibility, as temps plummeted into the teens here last night, also, the storm brought brought about 6-8" of snow to my area, with air that cold here, I figure that at least some of that cold will make it into the Appalachians in time for Sandy's fury.
The higher elevations might see some slushy accumulations, anyways, what the most serious concern is for now is beach erosion and coastal flooding, those are always frightening prospects in any coastal storm.