Why did Hurricane Sandy take such an unusual track into New Jersey?
We're used to seeing hurricane-battered beaches and flooded cities in Florida, North Carolina, and the Gulf Coast. But to see these images from the Jersey Shore and New York City in the wake of Hurricane Sandy is a shocking experience. New Jersey only rarely gets hit by hurricanes because it lies in a portion of the coast that doesn't stick out much, and is too far north. How did this happen? How was a hurricane able to move from southeast to northwest at landfall, so far north, and so late in hurricane season? We expect hurricanes to move from east to west in the tropics, where the prevailing trade winds blow that direction. But the prevailing wind direction reverses at mid-latitudes, flowing predominately west-to-east, due to the spin of the Earth. Hurricanes that penetrate to about Florida's latitude usually get caught up in these westerly winds, and are whisked northeastwards, out to sea. However, the jet stream, that powerful band of upper-atmosphere west-to-east flowing air, has many dips and bulges. These troughs of low pressure and ridges of high pressure allow winds at mid-latitudes to flow more to the north or to the south. Every so often, a trough in the jet stream bends back on itself when encountering a ridge of high pressure stuck in place ahead of it. These "negatively tilted" troughs have winds that flow from southeast to northwest. It is this sort of negatively tilted trough that sucked in Sandy and allowed the hurricane to take such an unusual path into New Jersey.
Figure 1. Inlet section of Atlantic City, N.J., after Hurricane Sandy. Image credit: 6 ABC Action News.
The 1903 Vagabond Hurricane
The only other hurricane to hit New Jersey since 1851 besides Sandy was the 1903 Category 1 Vagabond Hurricane. According to Wikipedia, the Vagabond Hurricane caused heavy damage along the New Jersey coast ($180 million in 2006 dollars.) The hurricane killed 57 people, and endangered the life of President Theodore Roosevelt, who was sailing on a yacht near Long Island, NY, when the hurricane hit. However, the Vagabond Hurricane hit in September, when the jet stream is typically weaker and farther to the north. It is quite extraordinary that Sandy was able to hit New Jersey in late October, when the jet stream is typically stronger and farther south, making recurvature to the northeast much more likely than in September.
Figure 2. The path of the 1903 Vagabond Hurricane, the only other hurricane to hit New Jersey since 1851.
The blocking ridge that steered Sandy into New Jersey
A strong ridge of high pressure parked itself over Greenland beginning on October 20, creating a "blocking ridge" that prevented the normal west-to-east flow of winds over Eastern North America. Think of the blocking ridge like a big truck parked over Greenland. Storms approaching from the west (like the fall low pressure system that moved across the U.S. from California to Pennsylvania last week) or from the south (Hurricane Sandy) were blocked from heading to the northeast. Caught in the equivalent of an atmospheric traffic jam, the two storms collided over the Northeast U.S., combined into one, and are now waiting for the truck parked over Greenland to move. The strength of the blocking ridge, as measured by the strength of the North Atlantic Oscillation (NAO), was quite high--about two standard deviations from average, something that occurs approximately 5% of the time. When the NAO is in a strong negative phase, we tend to have blocking ridges over Greenland.
Figure 3. Jet stream winds at a pressure of 300 mb on October 29, 2012, as Hurricane Sandy approached the coast of New Jersey. Note that the wind direction over New Jersey (black arrows) was from the southeast, due to a negatively tilted trough of low pressure over the Eastern U.S. caused by a strong blocking ridge of high pressure over Greenland. Image credit: NOAA/ESRL.
Arctic sea ice loss can cause blocking ridges
Blocking ridges occur naturally, but are uncommon over Greenland this time of year. According to NOAA's Climate Prediction Center, blocking near the longitude of Greenland (50°W) only occurs about 2% of the time in the fall. These odds rise to about 6% in winter and spring. As I discussed in an April post, Arctic sea ice loss tied to unusual jet stream patterns, three studies published in the past year have found that the jet stream has been getting stuck in unusually strong blocking patterns in recent years. These studies found that the recent record decline in Arctic sea ice could be responsible, since this heats up the pole, altering the Equator-to-pole temperature difference, forcing the jet stream to slow down, meander, and get stuck in large loops. The 2012 Arctic sea ice melt season was extreme, with sea ice extent hitting a record lows. Could sea ice loss have contributed to the blocking ridge that steered Sandy into New Jersey? It is possible, but we will need to much more research on the subject before we make such a link, as the studies of sea ice loss on jet stream patterns are so new. The author of one of the new studies, Dr. Jennifer Francis of Rutgers, had this say in a recent post by Andy Revkin in his Dot Earth blog: "While it’s impossible to say how this scenario might have unfolded if sea-ice had been as extensive as it was in the 1980s, the situation at hand is completely consistent with what I’d expect to see happen more often as a result of unabated warming and especially the amplification of that warming in the Arctic."
Jeff Masters
Reader Comments
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Another post-Sandy fake. Check at Snopes Sandy Fakes before reposting this kind of thing.
That's what an uncontrollable fire looks like. We see it in bush fires all over the world, especially when the Santa Ana wind gets a blowin'
Looks a lot like this shark! A lot!!
Tropical Cyclone Advisory #25
DEPRESSION, FORMER NILAM (BOB02-2012)
8:30 AM IST November 1 2012
=============================================
At 3:00 AM UTC, The depression over Rayalaseema and adjoining area of southern interior Karnataka moved westward and now lays near 14.0N 76.5E, near Chitradurga. The system will likely move northwestward and weaken further into a low pressure area during the next 12 hours.
Actually he should resign for misjudgement.
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The problem with the NOAA was that they bent the rules. Tropical storm warnings are announced when tropical storm conditions (sustained winds of 39 to 73 mph) are possible within the specified area within 48 hours. Well, according to their own rules NHC should have put the whole coast from North Carolina up to Massachusetts under a tropcial storm warning on last Saturday when the storm definitely still was a hurricane. The same for hurrciane warnings. They didn't. Sandy still was full tropical when tropical storm winds reached the coast. When the radius of maximum winds reached the New Jersey and Long Island coasts Sandy was still classified full tropical. While they got predictions of intensity, track, storm surge, and other hazards pretty exactly their forecasting philosophy was big fail.
According to their pamphlet (the PDF mentioned earlier on this blog) they did this for not confusing the public when tropical storm warnings/hurricane warnings would've ceased after et transition but still nor'easter/blizzard conditions would've continued for a long time (which in the area proper btw did not happen because Sandy absorbed much of the other systems, blizzard conditions f.ex. happened only in parts of the Appalachians which anyways would't have been under hurricane/tropical storm warnings). Putting up graphics with a tropcial storm warning at the coast of North Carolina but lacking warnings for the coast north of that while Sandy was smacking down on the coast as a hurricane was a really bad, bad solution. People are looking on graphics, they're not reading advisories – some are not able to read or they don't understand terminology. Within this blog readers mostly understand the difference between hurricane winds and hurricane-force winds, the general public does not know about the difference, nor they understand the why.
Whoever was responsible for that bad judgement within NOAA should resign as well.
Excuse me. This storm had the best warning, most advanced warning ever. It was called 11 days before at WU on NOAA data. Only local real estate types pooh-poohed it, including Bloomberg. Now you want to go hang someone because you had your life set on 'ignore'. Well, lah-ti-dah, that warning was for you.
I'm not sure you're paying attention to what the person wrote. They're talking about the official category for different areas of tropical storm / hurricane warnings, not that "NOAA didn't predict the storm". It's about a decision on whether to use a classification that has a psychological impact for many people or not.
And Matthias *certainly* wasn't talking about himself.
Rising Seas a Real Threat to New Jersey
Sea Level Rise Threatens Hundreds of U.S. Energy Facilities
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Hurricane Sandy Four Times More Powerful Than The 1991 Perfect Storm
Florence TCR
*Tropical Storm Aletta - PDF - KMZ
*Hurricane Bud - PDF - KMZ
*Hurricane Daniel - PDF - KMZ
*Hurricane Emilia - PDF - KMZ
Four EPAC TCRs issued.
Hurricane Sandy death toll reaches 74.
Link
Certainly not in the number of deaths. As to the financial and property loss, it might. I don't know enough about that and I think they are being careful not to compare them yet. I don't think they have a full handle on the cost of Sandy yet either.
I think when it's all said and done, Sandy will be the 2nd most destructive hurricane to hit the US, beating out Ike.
Watching GMA and they are doing a report on NJ on the damaged gas lines..towns have exposed gas lines that could go anytime..residents are still living there as they have no where to go..the situation is just getting dire by the minute..
There are still so many power outages and its dipping into freezing in some areas..
NY Red Cross @redcrossny
Now that it's safe 2 move vehicles &personel, 35 @redcross trucks en route 2 NYC with food, h20, snacks &cleanup supplies 4 distribution.
I hope all can have a good Thursday.
yes that's be posted last night
I agree, at 11am that morning in the discussion, the NHC said that a 20 N Mile eye had developed and a small area of deep convection still maintained. At that time, the east coast was receiving tropical storm force winds yet there was no TROPICAL STORM WARNINGS! And, 5 hours later she made landfall. Make no sense to me.
Yes, the NHC did a great job in correctly forecasting the track of the storm, and a very good job with the forecast of the intensity and the surge, but at the very least they did bend their own rules exactly as Matthias1967 described.
Speaking of Sandy, here are the latest sad statistics compiled from news sources and presented via Wikipedia:
Good morning and yes I agree with you and I usually do. I made a mistake and apologized but I shall do it again...please forgive my lapse.
Thanks again as always your perfection is underwhelming...oops must get coffee :)
Link
In this aspect NOAA has to get rid of the turf wars or whatever the problem is and integrate more tightly. This is reminds me of the 2005 Hurricane Stan debacle in a way. Why did they retire Stan? It was the WMO vs. NOAA on that one I think.
I disagree. The NHC has cried "wolf" a few times on the east coast and some have become complacent. Regardless, when the real thing comes along huffing and puffing and blowing their houses down, the NHC hides behind the strictist interpretation of a meteorlogical "Tropical Cyclone" to declare it non tropical about 50 miles offshore and not issue warnings. I think that was a mistake as the term "Hurricane Warning" seems to get more peoples attention in a way that other warnings don't.
Why did the media start calling it "Superstorm" Sandy, Cause the NHC stopped calling it a Hurricane and stopped issuing Hurricane and Tropical storm warnings. It's been show here and will probably be shown during the Barometer Bob show tonight your time that Sandy was warm cored up until and after landfall.
It even caught me out, I went to the NHC to see if Sandy was still a Hurricane and found she was but no watches or warnings cause they had passed Sandy over to the NWS.
Why did they hand it over to the NWS to issue watches and warnings?
Why not continue issuing watches and warnings?
Did the NHC stopping issuing these watches and warning make people become complacent?
Which sounds more foreboding Category 1 Hurricane Sandy or "Superstorm" Sandy.
Did people thinking that Sandy was only a Category 1 Hurricane before the handover make them think Sandy would have the same as Irene on landfall?
Did the NHC under-forecast the storm-tide? I remember seeing they predicted 6'-11' for New York/Battery Park.
These are just a few Questions I have.
Link
Have a great day everyone, bye.
I do get what a lot of people are saying but most people are familiar more with their local NWS offices than the NHC..the NWS offices issued high wind warnings for those areas so warnings were out there..by not labeling them tropical or hurricane warnings still dosent diminish the fact that wind warnings were issued..and was it really wind damage that caused the severity of the destruction..no it was the surge and flooding..In the NHC discussion they wrote "Life Threatening Surge Event"..that was the HUGE issue with Sandy and thats what they stressed about..All agencies acted approriately in my book..the media on the other hand is who I have issues with and people should call out..I even noticed in the latest updates that they are NOW using Hurricane Sandy instead of Superstorm Sandy..
No Aussie, the media was calling it Superstorm Sandy when it was down by the bahamas..the NHC had this label as a hurricane and all you saw in the headlines was "Superstorm Sandy heading for the Northeast"
I was watching TWC and CNN here, they were calling it Hurricane Sandy, now they call it Superstorm Sandy. I am not sure about the Media there. So I may be wrong on that one.
The NHC obviously did a fantastic job in predicting Sandy's timing, location, and intensity. In retrospect it's easy to claim they made the wrong call in not posting tropical warnings for NY and NJ, but all indications at the time were that Sandy would come ashore as a non-tropical entity, albeit a strong one. That is, of course, why they repeatedly tacked on the following to most of their pre-landfall discussions:
"AS NOTED IN PREVIOUS ADVISORIES...TO AVOID A HIGHLY DISRUPTIVE
CHANGE FROM TROPICAL TO NON-TROPICAL WARNINGS WHEN SANDY BECOMES
POST-TROPICAL...THE WIND HAZARD NORTH OF THE TROPICAL STORM WARNING
AREA WILL CONTINUE TO BE CONVEYED THROUGH HIGH WIND WATCHES AND
WARNINGS ISSUED BY LOCAL NATIONAL WEATHER SERVICE OFFICES."
And that would have, indeed, been "highly disruptive". Chaotic, even. Imagine had they posted hurricane watches and /or warnings on, say, Saturday, then had to change those back to high wind warnings; I can imagine many people might not have taken the situation seriously.
Having said all that, I agree that something needs to be done differently next time, for there will, indeed, be a next time. I'm not sure whether that means the NHC should post the hurricane warnings, and allow those to supersede any local WFO warnings in place, or a new hybrid type of entity needs to be created, such as a "Hurricane/Nor'easter Warning".
(I noticed that JB started relentlessly hammering the NHC fir their decision on Monday afternoon hours before the storm even made landfall. But it's been my experience that he relentlessly hammers the NHC--and the NWS, and NOAA, and rival private forecasters--for pretty much everything. He's like the gripy old guy at the bar; I tend to ignore his ranting. I wish more did.)
Interesting piece , Being rather new to the forum I like that both sides of the argument/debate are allowed to present their case ... Gives people a chance to make an informed opinion.
Please give an example of the NHC crying wolf. I don't think that's quite factual.
I did a search engine on Google "superstorm sandy" October 28, 2012 and for "superstorm sandy" October 27, 2012..go in and type in that same result and see all the headlines with that name in it and lets not forget Frankenstorm Sandy as well..
"A super storm is a freak occurrence that merges the tropics with the northern latitudes in explosive results! a similar setup might be happening early next week in the Northeast, let's explore!
I want to make it very clear that this is just a scenario that could possibly happen and that we are still a full week away from any of these scenarios happening, but I do think that there is a chance that this may actually take shape..."
That would be a shame , Like I said, I am rather new here and eager to come to an informed opinion and you cant come to that without hearing both sides of the story . But that is only my opinion.
Sandy was a complicated situation rarely experienced in the Atlantic basin. There are complicated sets of reasoning for why the warnings and forecasts were done the way they were. That does not necessarily mean that they were the "right" call (I use quotes because that is subjective), but important discussion will likely come of this from the almost certain service assessment.
One thing to keep in mind, however, is that forecasts for the strength and impacts of Sandy were particularly good in the context of how much lead time was available and how unique this situation was. Because the storm was not expected tropical, the equivalent non-tropical advisories were issued. The non-tropical equivalent products did not convey a weaker storm or weaker impacts, just the type of system. There will likely be evidence backing this up as the better call on a science basis, but maybe not on the political or social science basis. I'm not making a value judgement on either, as that will hopefully come from an objective service assessment.
Good things that can come from this... this could be yet another catalyst for re-evaluating how we treat hurricane/storm warnings. Beyond just separating impacts (surge/wind/rain), this might also suggest the need for threat-based warnings instead of storm-type-based warnings. So, for example, a storm surge warning might be issued for <5.0ft surge regardless of extratropical or tropical origin.
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