Wednesday, October 24, 2012

Is A Hard Left Turn Possible For Hurricane Sandy?


Sandy continues to steal the headlines as this massive storm matured into a Hurricane. Winds have been clocked near 100mph at times as Sandy spins in ferocious waves and rainfall all across Jamaica. Swaths of rain have battered parts of Cuba, the Dominican Republic as well as the Bahamas. Also, Sandy has picked up additional forward speed towards the north and eastern Cuba is next in line to experience lashing effect.

The short term forecast remains the same, but in the long term (meaning early next week), computer models are coming more into agreement that Sandy may take a hard left hook and move into the Mid-Atlantic or New England coastline, which is giving many meteorologists headaches.

Before I dive into the history of tropical systems and Sandy's future, it is still way too early to call an exact forecast on this system. However, its always good to be aware of this possible situation and have a plan in place.

As far as the future forecast of this potential beast, its always good to take a look at the past. Right now, there are several models that indicate this storm to take a dynamic turn to the east. When you look at the history of tropical systems, or even typical mid-latitude cyclones, its quite difficult to make such a turn. Now, its very likely for any system as they move from the tropics to the north and make a hard turn right (east) due to strong westerly winds. Therefore, a 100% PERFECT set up is needed in order for the worst case scenario to occur.

The following images illustrate a couple hurricanes that I found to make an improbable turn around the Mid-Atlantic and New England:

1) Hurricane Connie 1955


Here, Connie took a couple of turns. One, to parallel the coast, and two, a left turn inland. But, this is not a hard left turn like some models say Sandy can do.

2) Hurricane Agnes 1972

 
Following a dip into the Atlantic Ocean, Agnes took a turn back inland and created trouble for many, especially along Long Island.
 
Of all the tropical system that I took a glance at, I could not find one that had similar origins as Sandy. Climatology suggests that a topical system which originate in the Caribbean and move north to the Atlantic, tend to get caught up in the westerlies and brush out to sea.
 
On the other hand, one of the more destructive storms to ever hit the northeast was known as, "The Long Island Express," or the New England Hurricane of 1938.
 

This storm did not wobble uncontrollably, but rather was picked up by a trough which accelerated forward speed. For a time, The Long Island Express moved with speeds over 50mph. Therefore, it had no time to be pushed out to sea. With a combination of forward speed and strong winds, a gust over 180mph was recorded at Blue Hill Observatory in Massachusetts....WOW!

I am not saying that Sandy will do this, but history gives us an idea, that it is extremely difficult for a storm to back into the northeast.

Despite all the records that we have, history was meant to be rewritten....right? Well, history happens all the time as meteorology is still a young science, with huge growth potential. Forecasting and modeling have come a long way, but still have a long way to go.

Nonetheless, there are a couple of features that could make or break a major crisis for the Northeast.

If you read the last blog, we noted a blocking pattern in Greenland, and how the orientation of a trough needs to set up perfectly for a hard left turn.

As of this afternoon, models are beginning to hint that a negatively tilted trough could happen and bring Sandy off the Atlantic and draw the storm ashore. Following deep analysis of many computer models, they all point to one thing that will help draw Sandy inland.

A shortwave at the 500mb (18,000ft) level, coming in front Canada could swipe the south side of the storm and knock it back east. The following images are 500mb plots with the short wave, or area of concern is before gyrating this storm back east.

1) 12z GFS

 
2) 12z EURO
 


3) 12z NOGAPS



4) 12z Canadian (CMC)


Each of these model outputs note a shortwave that could trigger a directional turn. Now the question lies in how strong this short wave will be and when it will move through. If it moves in early, a direct hit will occur, but if it shows up late to the party, the food will be gone and it will miss the US.

Furthermore, there is one more aspect that I want to look at. Its how the jet stream in the GFS model is plotted.


Circled is the eastern side of the jet stream that has much stronger winds than the western side. If what I learned in school is correct, due to this feature and wind profile, the trough that will make or break the storm should lift, rather than deepen. In other words, if the trough lifts, the the storm will not happen. According to this feature, the storm will not happen.

Again, its still too early to call how this will shape up, but all I want to say is that based on history, its going to be extremely difficult for this storm to pull out all of its ammo and directly hit the US. The forecast can change and as additional data comes in over the next couple of days, computer information will begin to gel together. Overall, yes it is still possible for Sandy to pound the northeast.

For more news and weather you can log onto: www.facebook.com/plushnickweather or www.facebook.com/KAGSTV. You can also check out our twitter feeds: @KAGSweather and @KAGSnews. Furthermore, you can download our new weather app. Search: KAGS Weather, in the Apple App Store or Google Play for Android.


No comments:

Post a Comment