Slight possibility for another New England “perfect storm” this Hallowe’en

The perfect storm

The perfect storm at its peak, October 30, 1991. (NOAA)

The phrase “perfect storm” has been used and overused for a long time, but it comes from a real event, back in October 1991.

Meteorologist Jeff Masters at Weather Underground has looked at the models and thinks there is a small chance that something similar might happen this weekend/early next week in the Mid-Atlantic/New England coastal regions.

However, the National Hurricane Center, watching the situation closely, so far believes that Sandy and its remnants will travel safely out to sea, not causing any fuss on the East Coast.

October 1991

The US National Weather Service described as a “perfect storm” what happened when a frontal trough moving off the northeastern North American coast interacted with the remnants of former Hurricane Grace, pumping a lot of energy into it (no, I don’t understand the technical details) and converting it into a very powerful extratropical storm, that’s sometimes called the Halloween Storm.

This all happened close enough to New England and the New York coast to wreak havoc and kill 13 people. The Gloucester Times has a website on that, as well as the book and the movie about it.

1031 GFS

Current GFS model run showing in the upper righthand corner where Sandy or its remnants may be on Halloween 2012 – safely out to sea. (Source)

October 2012

Hurricane Sandy is currently rocking Jamaica and predicted to travel over Eastern Cuba and the Bahamas. After that, models vary. The National Hurricane Center is going with the very reliable GFS model, which consistently through the current run has been showing Sandy or its remnants being pulled out to sea by a strong atmospheric trough over the Central Atlantic.

However, some models, like the ECMWF, show another trough, one that is just starting to cross North America from west to east today, having an effect on Sandy or its remnants similar to the one that happened to Gloria back in 1991.

Here is what Dr. Masters said in his blog this morning:

1031ecmwf

Where the current ECMWF model puts Sandy or the extratropical storm on October 31st – this is the slightly possible “perfect storm” scenario. (Source)

On Friday, a very complicated meteorological situation unfolds, as Sandy interacts with a trough of low pressure approaching the U.S. East Coast and trough of low pressure over the Central Atlantic. The Central Atlantic trough may be strong enough to pull Sandy northeastwards, out to sea, as predicted by the official NHC forecast, and the 06Z GFS, 00Z UKMET, 00Z Canadian, and 06Z HWRF models (00Z is 8 pm EDT, and 06Z is 2 am EDT.) However, an alternative solution, shown by the 00Z ECMWF, 06Z GFDL, and 06Z NOGAPS models, is for Sandy to get caught up by the trough approaching the Eastern U.S., which will inject a large amount of energy into Sandy, converting it to a powerful subtropical storm that hits the mid-Atlantic or New England early next week with a central pressure below 960 mb and sustained winds of 60 – 70 mph. Such a storm would likely cause massive power outages and over a billion dollars in damage, as trees still in leaf take out power grids, and heavy rains and coastal storm surges create damaging flooding. The full moon is on Monday, which means astronomical tides will be at their peak for the month, increasing potential storm surge flooding. A similar meteorological situation occurred in October 1991, when Hurricane Grace became absorbed by a Nor’easter, becoming the so-called “Perfect Storm” that killed 13 people and did over $200 million in damage in the Northeast U.S.

Dr. Masters isn’t one of the “doomsayer” meteorologists – he’s pretty solid. So is the National Hurricane Center, of course, and they do not hesitate to mention at the earliest possible moment when there is doubt about a future forecast track. So far they haven’t said anything in their discussions. They probably are waiting, just as Dr. Masters is, for more data, now that the second trough is over land and can be sampled more thoroughly. We should know more this afternoon. I’ll update things tonight or tomorrow.



Categories: Weather

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: