November Atlantic hurricane outlook

By: Dr. Jeff Masters , 2:35 PM GMT on November 01, 2011

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Hurricane Rina is gone, and the tropical Atlantic is quiet, with no threat areas to discuss, and no models predicting development of a tropical depression during the coming seven days. So, are we all done for 2011? Or will this seventh-busiest hurricane season of all-time spawn a Tropical Storm Sean? Let's try and come up some answers. Since the active hurricane period we are in began in 1995, ten of the sixteen years (62%) have seen one or more Atlantic named storms form after November 1, for a total of fifteen late-season storms:

2009: Hurricane Ida on November 4
2008: Hurricane Paloma on November 6
2007: Tropical Storm Olga on December 11
2005: the "Greek" storms Gamma, Delta, Epsilon, and Zeta
2004: Tropical Storm Otto on November 29
2003: Odette and Peter in December
2001: Hurricane Noel on November 5 and Hurricane Olga on November 24
1999: Hurricane Lenny on November 14
1998: Hurricane Nicole on November 24
1996: Hurricane Marco on November 19

Only three of these storms (20%) caused loss of life: Hurricane Ida of 2009, which killed one boater on the Mississippi River; Tropical Storm Odette of 2007, whose floods killed eight people in the Dominican Republic; and Hurricane Lenny of 1999, which killed fifteen people in the Lesser Antilles. "Wrong-way Lenny" was both the deadliest and the strongest November hurricane on record (Category 4, 155 mph winds). There have been only seven major Category 3 or stronger hurricanes in the Atlantic after November 1. Part of the reason for the relatively low loss of life for November storms is that they tend to form from extratropical low pressure systems that get cut off from the jet stream and linger over the warm waters of the subtropical Atlantic. These type of systems typically get their start in the middle Atlantic, far from land, and end up recurving northeastwards out to sea. However, as I noted in the wake of last year's Hurricane Tomas last November in my blog post, Deadly late-season Atlantic hurricanes growing more frequent, It used to be that late-season hurricanes were a relative rarity--in the 140-year period from 1851 - 1990, only 30 hurricanes existed in the Atlantic on or after November 1, an average of one late-season hurricane every five years. Only four major Category 3 or stronger late-season hurricanes occurred in those 140 years, and only three Caribbean hurricanes. But in the past twenty years, late-season hurricanes have become 3.5 times more frequent--there have been fifteen late-season hurricanes, and five of those occurred in the Caribbean. Three of these were major hurricanes, and were the three strongest late-season hurricanes on record. Dr. Jim Kossin of the University of Wisconsin published a 2008 paper in Geophysical Research Letters titled, "Is the North Atlantic hurricane season getting longer?" He concluded that yes, there is an "apparent tendency toward more common early- and late-season storms that correlates with warming Sea Surface Temperature but the uncertainty in these relationships is high". The recent increase in powerful and deadly November hurricanes would seem to support this conclusion.


Figure 1. The strongest hurricane on record in the Atlantic in November, Hurricane Lenny, takes aim at the Lesser Antilles on November 17, 1999. Image credit: NOAA.

Forecast for November 2011
The oceans are certainly warm enough to support continued development of tropical cyclones. Sea Surface Temperatures (SSTs) over a wide area of the tropical Atlantic are 0.5 - 1.0°C above average, and are well above the 26°C (79°F) threshold typically needed to support tropical storm formation (Figure 2.) However, wind shear is starting to rise over much of the tropical Atlantic as the jet stream moves farther south in its usual seasonal cycle. Wind shear over most of the Atlantic will be too high to support tropical storm formation over the coming two weeks, according to the latest run of the GFS model (Figure 3.) Only the southern Caribbean and a few transient pockets in the middle Atlantic east and southeast of Bermuda will have low enough wind shear to support tropical storm formation over the next two weeks. The African Monsoon is quiet this time of year, and we no longer have African waves coming off the coast of Africa that can act as the seeds for formation of a tropical storm in the Caribbean. If we do get a tropical storm, it will probably be to the northeast of the Lesser Antilles, far from land, in a region where an extratropical low pressure system gets cut off from the jet stream and lingers long enough over warm waters to acquire tropical characteristics and get a name. Both the GFS and ECMWF models are suggesting a system like this may take form 7 - 10 days from now. Taking all these factors into account, I predict we are all done this hurricane season with storms that will cause loss of life, but there is still a 70% chance that we will get one or more named storms in the middle Atlantic that will stay out to sea and not affect land.


Figure 2. Sea surface temperatures in the Atlantic on November 1, 2011. The black dotted line is the 26°C (79°F) isotherm, which marks the boundary where tropical storm formation can typically occur. A large portion of the Atlantic is still capable of supporting tropical storm formation.


Figure 3. Wind shear forecast for November 11, 2011, as predicted by the 2am EDT November 1, 2011 run of the GFS model. The model is predicting low wind shear of less than 4 m/s (about 8 knots, light red colors) in the southern Caribbean and southern Lesser Antilles Islands. Very high wind shear in excess of 44 m/s (85 knots, orange colors), associated with the jet stream, will protect regions north of the Caribbean.

I'll have a new post Wednesday or Thursday.

Jeff Masters

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Quoting Tazmanian:


I bet you wish you were there, huh? ;)
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Quoting KoritheMan:


Yeah, a friend of mine in Fort Collins was saying the other day that they've had their first snowfall.



there forcasting 5 too 10" of snow
Member Since: May 21, 2006 Posts: 5091 Comments: 114702
Ah, this should be fun. I am writing Don's report, and am right up to the point where he attained peak intensity.

It should be rather interesting to analyze the possible reasons for his abrupt weakening.
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Quoting BaltimoreBrian:


Thanks! That was the first one to have a religious angle--in the previous 5 battles I covered religion was not a factor.

That was the background---over the next week I'll write up an account of the storms and the battles the Spanish Armada was in.


Looking forward to it!
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Quoting Tazmanian:



doing well


Devener is off too a good start has far has snow gos


Yeah, a friend of mine in Fort Collins was saying the other day that they've had their first snowfall.
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Quoting KoritheMan:


Reading it now. Hey, it even carries some faint religious connotations. You I like!


Thanks! That was the first one to have a religious angle--in the previous 5 battles I covered religion was not a factor.

That was the background---over the next week I'll write up an account of the storms and the battles the Spanish Armada was in.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting KoritheMan:


How are you?



doing well


Devener is off too a good start has far has snow gos
Member Since: May 21, 2006 Posts: 5091 Comments: 114702
Quoting Tazmanian:



hi


How are you?
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Quoting TropicalAnalystwx13:
My best guesses:

Arlene: 70 mph
Bret: 70 mph
Cindy: 70 mph
Don: 50 mph
Emily: 50 mph
Franklin: 60 mph
Gert: 65 mph
Harvey: 65 mph
Irene: 120 mph
Jose: 45 mph
Katia: 135 mph
Lee: 60 mph
Maria: 75 mph
Nate: 70 mph
Ophelia: 145 mph
Philippe: 100 mph
Rina: 115 mph


Let's just pretend Lee doesn't exist.
Member Since: Posts: Comments:
My best guesses:

Arlene: 70 mph
Bret: 70 mph
Cindy: 70 mph
Don: 50 mph
Emily: 50 mph
Franklin: 60 mph
Gert: 65 mph
Harvey: 65 mph
Irene: 120 mph
Jose: 45 mph
Katia: 135 mph
Lee: 60 mph
Maria: 75 mph
Nate: 70 mph
Ophelia: 145 mph
Philippe: 100 mph
Rina: 115 mph
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting KoritheMan:


Hey Taz!



hi
Member Since: May 21, 2006 Posts: 5091 Comments: 114702
Quoting yqt1001:


I'm going to follow along with TA13 here..did you make Arlene a hurricane? I strongly think she was one at landfall.

Unfortunately, I can't find a microwave pass directly before landfall, but there is this right after landfall:



(Last microwave pass before landfall was this, 12 hours before the pass when she was over land)

This was her IR at landfall:




That's pretty much my only reasoning.


I put her at 60 kt.
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Quoting KoritheMan:
On another note, I have a new found respect for the NHC's work. I am in the process of writing a blog highlighting the events of the 2011 Atlantic and East Pacific hurricane seasons. The historical comparisons on the Atlantic portion are done, but unfortunately, the TCRs are not. Other than a paraphrasing of the select few the NHC currently has written, I am doing these reports entirely myself, using various data. Arlene's report alone took me three hours.

It's tougher than you'd think!


I'm going to follow along with TA13 here..did you make Arlene a hurricane? I strongly think she was one at landfall.

Unfortunately, I can't find a microwave pass directly before landfall, but there is this right after landfall:



(Last microwave pass before landfall was this, 12 hours before the pass when she was over land)

This was her IR at landfall:




That's pretty much my only reasoning.
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Quoting Tazmanian:
YAWN


Hey Taz!
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YAWN
Member Since: May 21, 2006 Posts: 5091 Comments: 114702
Quoting CybrTeddy:


I wouldn't consider Gustav a dangerous Caribbean Cruiser, he only got powerful as he approached Cuba in the Western Caribbean. I'm talking about Gilbert, Allen, Dean, and Felix situations. High being strong enough to force them straight west into Central America or Texas while being very powerful all the way through.


You may have an opportunity for such an event next year, if the synoptic pattern mimics past La Nina years.
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Quoting TropicalAnalystwx13:

No, they left a long time ago.


Bummer.
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Quoting KoritheMan:
Did... did everyone just go to bed?

No, they left a long time ago.
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting KoritheMan:


Gustav?


I wouldn't consider Gustav a dangerous Caribbean Cruiser, he only got powerful as he approached Cuba in the Western Caribbean. I'm talking about Gilbert, Allen, Dean, and Felix situations. High being strong enough to force them straight west into Central America or Texas while being very powerful all the way through.
Member Since: July 8, 2005 Posts: 259 Comments: 23561
Did... did everyone just go to bed?
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Quoting KoritheMan:


Finished. History and religion are both my strongest interests (next to weather), so I greatly enjoyed it!

No you didn't. You just think you did.

lol.
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting KoritheMan:


Reading it now. Hey, it even carries some faint religious connotations. You I like!


Finished. History and religion are both my strongest interests (next to weather), so I greatly enjoyed it!
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Quoting TropicalAnalystwx13:

and why not?


Neither the satellite nor microwave signature were impressive enough.
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Quoting BaltimoreBrian:
I imagine so Koritheman.

Drop by my blog sometime before I go.


Reading it now. Hey, it even carries some faint religious connotations. You I like!
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Quoting KoritheMan:


Since the NHC already did her report, no. But I wouldn't have anyway.

and why not?
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting TropicalAnalystwx13:

Did you make Cindy a hurricane?


Since the NHC already did her report, no. But I wouldn't have anyway.
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Quoting KoritheMan:


It's okay. Everyone is at some point. Admitting it shows character.

Whoo! I got character!

lol.
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting KoritheMan:
On another note, I have a new found respect for the NHC's work. I am in the process of writing a blog highlighting the events of the 2011 Atlantic and East Pacific hurricane seasons. The historical comparisons on the Atlantic portion are done, but unfortunately, the TCRs are not. Other than a paraphrasing of the select few the NHC currently has written, I am doing these reports entirely myself, using various data. Arlene's report alone took me three hours.

It's tougher than you'd think!

Did you make Cindy a hurricane?
Member Since: July 6, 2010 Posts: 113 Comments: 31412
I imagine so Koritheman.

Drop by my blog sometime before I go.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting TropicalAnalystwx13:

I was wrong. :P


It's okay. Everyone is at some point. Admitting it shows character.
Member Since: Posts: Comments:
On another note, I have a new found respect for the NHC's work. I am in the process of writing a blog highlighting the events of the 2011 Atlantic and East Pacific hurricane seasons. The historical comparisons on the Atlantic portion are done, but unfortunately, the TCRs are not. Other than a paraphrasing of the select few the NHC currently has written, I am doing these reports entirely myself, using various data. Arlene's report alone took me three hours.

It's tougher than you'd think!
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Might as well be a quiet season while I'm deployed--wouldn't want to miss anything :)
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting BaltimoreBrian:


We're talking about the third year. So it would be just 1956, 1976 and 2000.

Darn :(
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting TropicalAnalystwx13:

Ah, but that is where you are wrong, good sir..I have looked it up, using those seasons you listed. ;)

1954: 1069 fatalities/$751.6 million (1954 USD)
1955: 1518 fatalities/$1.2 billion (1955 USD)
1956: 76 fatalities/$67.8 million (1956 USD)
1974: >8270 fatalities/$2 billion (1974 USD)
1975: 80 fatalities/$490 million (1975 USD)
1976: 72 fatalities/$100 million (1976 USD)
1998: >12000 fatalities/$12.2 billion (1998 USD)
1999: 465 fatalities/$5.9 billion (1999 USD)
2000: 50 fatalities/$1.2 billion (2000 USD)

Seems very deadly and destructive to me, no?


We're talking about the third year. So it would be just 1956, 1976 and 2000.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting KoritheMan:


Afraid not. That's a logical fallacy called "argumentum ad populum".

You are still young so there is hope for you. Don't go through life without ever being skeptical. Do not believe something just because me, Levi, or Drak say it. Research it yourself if it seems dubious or questionable.

I was wrong. :P
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting BaltimoreBrian:


Everyone here being acquainted with the "argumentum ad hominem" :P


;)
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Quoting BaltimoreBrian:
How about empirical research? Were the 1956, 1976 and 2000 seasons especially destructive and dangerous?

No, not really.


Correct. I was going to say this, but opted to do otherwise because again, we lack an adequate sample size. Give us at least two more such periods to draw a meaningful conclusion.

It should be noted though, that if we're going this route, 2000 did have an active Caribbean season (Chris, Debby, Ernesto, Gordon, Helene, Joyce, and Keith), it's just that many of the storms there were ripped apart by strong shear. Meaning, it could have been deadly.
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Quoting KoritheMan:


Afraid not. That's a logical fallacy called "argumentum ad populum".

You are still young so there is hope for you. Don't go through life without ever being skeptical. Do not believe something just because me, Levi, or Drak say it. Research it yourself if it seems dubious or questionable.


Everyone here being acquainted with the "argumentum ad hominem" :P
Member Since: August 9, 2011 Posts: 26 Comments: 8554
How about empirical research? Were the 1956, 1976 and 2000 seasons especially destructive and dangerous?

No, not really.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting TropicalAnalystwx13:

Well, usually, if a lot of people are saying that, it probably means it is a fact. ;)


Afraid not. That's a logical fallacy called "argumentum ad populum".

You are still young so there is hope for you. Don't go through life without ever being skeptical. Do not believe something just because me, Levi, or Drak say it. Research it yourself if it seems dubious or questionable.
Member Since: Posts: Comments:
Quoting KoritheMan:


I don't know why people keep saying this. We have a very small sample size for calculating that (1954-1956, 1974-1976, and 1998-2000).

Well, usually, if a lot of people are saying that, it probably means it is a fact. ;)
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting TropicalAnalystwx13:
Correct me if I am mistaken, but aren't third year Neutral/La Ni�a seasons typically very dangerous?


I don't know why people keep saying this. We have a very small sample size for calculating that (1954-1956, 1974-1976, and 1998-2000).
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Quoting CybrTeddy:


There hasn't been a truly dangerous storm in the Western Caribbean since Paloma, and there hasn't been a dangerous Caribbean cruiser in 4 and a half years.


Gustav?
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Quoting yqt1001:


I believe so, yes. 3rd year La Nina's usually have a more active Caribbean season and a less active CV season. Less storms, but more damage because less storms head out to sea. For 2012, I'm thinking that we could have some horrible storms in the Caribbean because there has been so little heat released in there this year (so far at least, but no models are showing a Paloma/Lenny coming in the next week).


There hasn't been a truly dangerous storm in the Western Caribbean since Paloma, and there hasn't been a dangerous Caribbean cruiser in 4 and a half years.
Member Since: July 8, 2005 Posts: 259 Comments: 23561
Quoting TropicalAnalystwx13:
Correct me if I am mistake, but aren't third year Neutral/La Niña seasons typically very dangerous?


I believe so, yes. 3rd year La Nina's usually have a more active Caribbean season and a less active CV season. Less storms, but more damage because less storms head out to sea. For 2012, I'm thinking that we could have some horrible storms in the Caribbean because there has been so little heat released in there this year (so far at least, but no models are showing a Paloma/Lenny coming in the next week).
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Quoting washingtonian115:
D.C as far as I've seen with my own eyes is very saturated right now.Thank godness we're getting a dry week ahead.Baltimore is probally very wet as well.


Washington D.C Reagan National:

Rainfall to date 40.05", normal today 33.63", 6.42" above normal

Washinton Dulles:

Rainfall to date 39.56", normal today 35.29", 4.27" above normal.

Baltimore:

Rainfall to date 49.64", normal today 35.32", 14.32" above normal.

Rainfall is 20" or more above normal over much of Pennsylvania, New Jersey, and southeast New York State.

Harrisburg PA is more than 30" above normal for the year. More than 31" above normal actually.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Correct me if I am mistaken, but aren't third year Neutral/La Nia seasons typically very dangerous?
Member Since: July 6, 2010 Posts: 113 Comments: 31412
Quoting BaltimoreBrian:


August 9th. It should say that.

Drop by my blog if you like.
Lol.I modified my comment because I relized our join dates are on the bottom of our post.
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Quoting BaltimoreBrian:



I'd love to know what the total rainfall over the USA has been this year. Maybe it's been close to normal with all the dry and wet places. cancelling each other out.
D.C as far as I've seen with my own eyes is very saturated right now.Thank godness we're getting a dry week ahead.Baltimore is probally very wet as well.
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Quoting washingtonian115:
Hey!.When did you join?


August 9th. It should say that.

Drop by my blog if you like.
Member Since: August 9, 2011 Posts: 26 Comments: 8554
Quoting bohonkweatherman:
Harrisburg is only 56.97 ahead of me. :) I hate this Texas drought, there has been NO improvement where I live.



I'd love to know what the total rainfall over the USA has been this year. Maybe it's been close to normal with all the dry and wet places. cancelling each other out.
Member Since: August 9, 2011 Posts: 26 Comments: 8554

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.