NOAA predicts an active Atlantic hurricane season: 15 named storms, 8 hurricanes

By: Dr. Jeff Masters , 4:08 PM GMT on May 19, 2011

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The National Oceanic and Atmospheric Administration (NOAA) issued its 2011 Atlantic hurricane season forecast today. NOAA forecasts a very active and possibly hyperactive season. They give a 65% chance of an above-normal season, a 25% chance of a near-normal season, and just a 10% chance of a below-normal season. NOAA predicts a 70% chance that there will be 12 - 18 named storms, 6 – 10 hurricanes, and 3 - 6 major hurricanes, with an Accumulated Cyclone Energy (ACE) 105% - 200% of the median. If we take the midpoint of these numbers, NOAA is calling for 15 named storms, 8 hurricanes, 4.5 major hurricanes, and an ACE index 152% of normal. A season with an ACE index over 165% is considered "hyperactive." An average season has 10 – 11 named storms, 6 hurricanes, and 2 intense hurricanes. Hurricane seasons during 1995-2010 have averaged about 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index 151% of the median. NOAA classifies 11 of the 16 seasons since 1995 as above normal, with eight being hyperactive. Only five seasons since 1995 have not been above normal, which include four El Niño years (1997, 2002, 2006, and 2009), and the 2007 season.

The forecasters cited the following main factors that will influence the coming season:

1) Above-average sea surface temperatures (SSTs) are expected in the hurricane Main Development Region (MDR), from the Caribbean to the coast of Africa between between 10°N and 20°N. SSTs in the MDR during April were about 0.5°C above average, the 14th warmest April SSTs in the past 100 years. This is far below last year's record 1.4°C anomaly, but still plenty warm enough to help drive above-average Atlantic hurricane activity. Long-range computer forecast models are predicting a continuation of these above-average SSTs through the peak part of hurricane season.

2) We are in an active period of hurricane activity that began in 1995, thanks to a natural decades-long cycle in hurricane activity called the Atlantic Multidecadal Oscillation (AMO): "During 1995-2010, some key aspects of the tropical multi-decadal signal within the MDR have included warmer than average SSTs, reduced vertical wind shear and weaker easterly trade winds, below-average sea-level pressure, and a configuration of the African easterly jet that is more conducive to hurricane development from tropical waves moving off the African coast. Many of these atmospheric features typically become evident during late April and May, as the atmosphere across the tropical Atlantic and Africa begins to transition into its summertime monsoon state."

3) An El Niño event is not expected this year: "Another climate factor known to significantly impact Atlantic hurricane activity is the El Niño-Southern Oscillation (ENSO.) The three phases of ENSO are El Niño, La Niña, and ENSO-Neutral. El Niño events tend to suppress Atlantic hurricane activity, while La Niña events tend to enhance it (Gray 1984). Currently, the 2010-11 La Niña episode is dissipating. Based on observations and ENSO forecast models, ENSO-Neutral conditions are likely during the 2011 Atlantic hurricane season."

4) NOAA is increasingly using output from ultra-long range runs of the computer forecast models we rely on to make day-to-day weather forecasts, for their seasonal hurricane forecasts: "The outlook also takes into account dynamical model predictions from the NOAA Climate Forecast System (CFS), the European Centre for Medium Range Weather Forecasting (ECMWF), the United Kingdom Meteorology (UKMET) office, and the EUROpean Seasonal to Inter-annual Prediction (EUROSIP) ensemble. These models are indicating a high likelihood of an above normal season."

How accurate are the NOAA seasonal hurricane forecasts?
A talk presented by NHC's Eric Blake at the 2010 29th Annual AMS Conference on Hurricanes and Tropical Meteorology studied the accuracy of NOAA's late May seasonal Atlantic hurricane forecasts, using the mid-point of the range given for the number of named storms, hurricanes, intense hurricanes, and ACE index. Over the past twelve years, a forecast made using climatology was in error, on average, by 3.6 named storms, 2.5 hurricanes, and 1.7 intense hurricanes. NOAA's May forecast was not significantly better than climatology for these quantities, with average errors of 3.5 named storms, 2.3 hurricanes, and 1.4 intense hurricanes. Only NOAA's May ACE forecast was significantly better than climatology, averaging 58 ACE units off, compared to the 74 for climatology. Using another way to measure skill, the Mean Squared Error, May NOAA forecasts for named storms, hurricanes, and intense hurricanes had a skill of between 5% and 21% over a climatology forecast (Figure 2). Not surprisingly, NOAA's August forecasts were much better than the May forecasts, and did significantly better than a climatology forecast.


Figure 1. Mean absolute error for the May and August NOAA seasonal hurricane forecasts (1999 - 2009 for May, 1998 - 2009 for August), and for forecasts made using climatology from the past five years. A forecast made using climatology was in error, on average, by 3.6 named storms, 2.5 hurricanes, and 1.7 intense hurricanes. NOAA's May forecast was not significantly better than climatology for these quantities, with average errors of 3.5 named storms, 2.3 hurricanes, and 1.4 intense hurricanes. Only NOAA's May ACE forecast was significantly better than climatology, averaging 58 ACE units off, compared to the 74 for climatology. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

How do NOAA's seasonal hurricane forecasts compare to CSU and TSR?
Two other major seasonal hurricane forecasts will be released over the next two weeks. On June 1, Phil Klotzbach and Bill Gray of Colorado State University (CSU) issue their forecast, and the British firm Tropical Storm Risk (TSR) will issue their outlook on May 24. A three-way comparison of the forecast accuracy of the three groups' forecast (Figure 2) reveals that all three organizations enjoy some success at making accurate seasonal forecasts, with NOAA and CSU making the best late May/early June forecasts overall. While the skill of these forecasts is low, they are useful for businesses such as the insurance industry.


Figure 2. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 1999-2009 (May) and 1998-2009 (August). using the Mean Squared Error. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

Jeff Masters

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Quoting VAbeachhurricanes:


will there be coke as well? nothing better than some rum&coke on the beach watching the world end.


it would greatly help me preserve what little there is left of my reputation....if you would capitalize the word 'Coke'...
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Quoting VAbeachhurricanes:


True, I can't think of anything more enjoyable than 500 inflatable animals in my yard when I wake up.

Your'e very weird....
Have you spoken to anyone about this?

heheheheh
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Quoting kimoskee:
You guys are hilarious!!! I love it!!!

I always enjoy this time on the blog, pre-hurricane before the crazys come out.

My husband can't understand how I can be reading a weather blog and laughing so hard.

Keep it up!


Same here -- I love the time in between the AGW debaters and the hurricane crazies.

It's always why I peek in here a month or two early.
Member Since: October 15, 2008 Posts: 11 Comments: 2312
Quoting presslord:


yup...we have a bottle of rum with your name on it....it's a very big bottle


will there be coke as well? nothing better than some rum&coke on the beach watching the world end.
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Quoting kimoskee:
You guys are hilarious!!! I love it!!!

I always enjoy this time on the blog, pre-hurricane before the crazys come out.

My husband can't understand how I can be reading a weather blog and laughing so hard.

Keep it up!

Lucky you.
My wife is in the UK. I wont have anyone's hand to hold as I lift off.
(I am assuming that I am joining the Throng, you see).
Come to think of it, I am pretty sure that in the UK they dont even know we are about to achieve Nirvana on Saturday.
Their loss, I'm sure.
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Quoting pottery:

True. I had not considered that.
But still. I really think that you should go with the Neapolitan Option.
A couple canisters of co2 and you could send all those homeless critters into oblivion. Where they will be much happier, you know.
And who knows where they may end up? Think of it as a kind of Educational Lottery for them. And, think of the reaction of the people who wake up and find that their yards are 4 feet deep in inflatable Labradors and stuff.
It will be a grand experience for them too.


True, I can't think of anything more enjoyable than 500 inflatable animals in my yard when I wake up.
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Quoting Jax82:


Well, it truly will be a the 'graveyard shift' thanks to Rapture.


+1 hahaha
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Quoting kimoskee:
You guys are hilarious!!! I love it!!!

I always enjoy this time on the blog, pre-hurricane before the crazys come out.

My husband can't understand how I can be reading a weather blog and laughing so hard.

Keep it up!


Maybe I should have said pre-rapture!
Member Since: Posts: Comments:
Quoting pottery:

Yeah. Me too. Your beach party still 'on'?
I think I'll be there, in spirits.


yup...we have a bottle of rum with your name on it....it's a very big bottle
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344. Jax82
Quoting aquak9:
Man...I'm gonna be at work saturday till 11pm EST. Wonder if they'll pay me for my full shift.


Well, it truly will be the 'graveyard shift' thanks to Rapture.
Member Since: September 2, 2008 Posts: 1 Comments: 1261
You guys are hilarious!!! I love it!!!

I always enjoy this time on the blog, pre-hurricane before the crazys come out.

My husband can't understand how I can be reading a weather blog and laughing so hard.

Keep it up!
Member Since: Posts: Comments:
Quoting Grothar:


He usually drops in when there is something going on. I guess he doesn't go in for idle banter. I really enjoy when he and Levi exchange opinions. It is like watching a tennis match. Both very bright.
very true
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Quoting presslord:


...well....I gotta say....I was pretty darned skeptical...but I can't argue with this sorta clear logic.....

Yeah. Me too. Your beach party still 'on'?
I think I'll be there, in spirits.
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.."its dee end of dee World as we know it and I feels fine"..
Member Since: July 3, 2005 Posts: 426 Comments: 128627
Quoting VAbeachhurricanes:


True, but the fact there is no feeding and no cleaning up after them must be a huge plus.

True. I had not considered that.
But still. I really think that you should go with the Neapolitan Option.
A couple canisters of co2 and you could send all those homeless critters into oblivion. Where they will be much happier, you know.
And who knows where they may end up? Think of it as a kind of Educational Lottery for them. And, think of the reaction of the people who wake up and find that their yards are 4 feet deep in inflatable Labradors and stuff.
It will be a grand experience for them too.
Member Since: Posts: Comments:
Quoting presslord:


...well....I gotta say....I was pretty darned skeptical...but I can't argue with this sorta clear logic.....

With that said I guess I won't need the shirt.
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2011 Atlantic Hurricane Outlook (video)
Member Since: November 24, 2005 Posts: 635 Comments: 26652
There will be a rapture the Bible promises it however we will never know the day or the hour that the rapture will take place. The Bible states that no man will know the day or the hour. Why does this change with family radio?
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Quoting VAbeachhurricanes:
Here's proof that it will happen saturday:

1. According to Camping, the number five equals "atonement", the number ten equals "completeness", and the number seventeen equals "heaven".

2. Christ is said to have hung on the cross on April 1, 33 AD. The time between April 1, 33 AD and April 1, 2011 is 1,978 years.

3. If 1,978 is multiplied by 365.2422 days (the number of days in a solar year, not to be confused with the lunar year), the result is 722,449.

4. The time between April 1 and May 21 is 51 days.

5. 51 added to 722,449 is 722,500.

6.(5 × 10 × 17)2 or (atonement × completeness × heaven)2 also equals 722,500.

How bout that Nonbelievers!



...well....I gotta say....I was pretty darned skeptical...but I can't argue with this sorta clear logic.....
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... and speaking of Japan earthquakes.

Japan Earthquake Shifted Seafloor by 79 Feet
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Here's proof that it will happen saturday:

1. According to Camping, the number five equals "atonement", the number ten equals "completeness", and the number seventeen equals "heaven".

2. Christ is said to have hung on the cross on April 1, 33 AD. The time between April 1, 33 AD and April 1, 2011 is 1,978 years.

3. If 1,978 is multiplied by 365.2422 days (the number of days in a solar year, not to be confused with the lunar year), the result is 722,449.

4. The time between April 1 and May 21 is 51 days.

5. 51 added to 722,449 is 722,500.

6.(5 x 10 x 17)^2 or (atonement x completeness x heaven)2 also equals 722,500.

How bout that Nonbelievers!

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The storm that's been snowing, raining, hailing, fogging, misting, and graupeling on us for the past couple days is spinning off some nasty stuff in Kansas. Watch out folks... I think this system has a bad attitude.

Member Since: March 26, 2006 Posts: 44 Comments: 1520
Quoting pottery:

Er, I make no such promise.
I mean, how do I explain the fact that my house is swarming with inflatable crocodiles, rodents of all descriptions, and dogs, cats and bunnyrabits and panthers when my wife gets back ?
She already has some misgivings....


True, but the fact there is no feeding and no cleaning up after them must be a huge plus.
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Quoting VAbeachhurricanes:


Well, as long as you promise to blow them back up as soon as you get them. They don't like being flat much.

Er, I make no such promise.
I mean, how do I explain the fact that my house is swarming with inflatable crocodiles, rodents of all descriptions, and dogs, cats and bunnyrabits and panthers when my wife gets back ?
She already has some misgivings....
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Quoting hurricaneben:
. Dang, signs of the upcoming Rapture?


In this case, it is spelled rupture, as in, the earths crust.:)
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Quoting Patrap:



A dynamically-based method for forecasting tropical cyclogenesis
location in the Atlantic sector using global model products
Zhuo Wang,1 Michael T. Montgomery,1 and Timothy J. Dunkerton1,2



A real-time forecast method is developed for prediction
of the tropical cyclogenesis location over the Atlantic using
global model operational products. The method is based on
the marsupial theory for tropical cyclogenesis proposed in a
recent observational study. A moisture front is usually found
ahead of the precursor wave trough, which separates the
relatively dry air outside of the wave pouch (a region of
closed circulation) from the relatively moist air inside the
wave pouch. The propagation speed of the pouch can be
determined by tracking the propagation of this moisture
front, and the intersection of the critical surface and the
trough axis pinpoints the predicted genesis location. Using
the global model operational products the genesis location
can be predicted up to three days in advance with an error
less than 200 km, which can provide useful guidance for
forecasters and flight planning. Citation: Wang, Z., M. T.
Montgomery, and T. J. Dunkerton (2009), A dynamically-based
method for forecasting tropical cyclogenesis location in the
Atlantic sector using global model products, Geophys. Res. Lett.,
36, L03801, doi:10.1029/2008GL035586.

That's fascinating!
Printed it for closer reading later.
Really looks like they have come up with a wonderful piece of research conclusion.
And if it stands up under further scrutiny, it will be a big assist to forecasters and everyone else too.
Great work by them.
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Quoting PcolaDan:
Earthquake Information (Information on seismic intensity at each site)
Issued at 09:51 JST 20 May 2011

Occurred at(JST)Latitude(degree)Longitude(degree)Depth Magnitude Region Name
09:46 JST 20 May 2011 35.8N 141.3E 30 km 5.8 Ibaraki-ken Oki
. Dang, signs of the upcoming Rapture?
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Quoting pottery:

Only if they have been deflated, fed, and are house trained.


Well, as long as you promise to blow them back up as soon as you get them. They don't like being flat much.
Member Since: Posts: Comments:



A dynamically-based method for forecasting tropical cyclogenesis
location in the Atlantic sector using global model products
Zhuo Wang,1 Michael T. Montgomery,1 and Timothy J. Dunkerton1,2



A real-time forecast method is developed for prediction
of the tropical cyclogenesis location over the Atlantic using
global model operational products. The method is based on
the marsupial theory for tropical cyclogenesis proposed in a
recent observational study. A moisture front is usually found
ahead of the precursor wave trough, which separates the
relatively dry air outside of the wave pouch (a region of
closed circulation) from the relatively moist air inside the
wave pouch. The propagation speed of the pouch can be
determined by tracking the propagation of this moisture
front, and the intersection of the critical surface and the
trough axis pinpoints the predicted genesis location. Using
the global model operational products the genesis location
can be predicted up to three days in advance with an error
less than 200 km, which can provide useful guidance for
forecasters and flight planning. Citation: Wang, Z., M. T.
Montgomery, and T. J. Dunkerton (2009), A dynamically-based
method for forecasting tropical cyclogenesis location in the
Atlantic sector using global model products, Geophys. Res. Lett.,
36, L03801, doi:10.1029/2008GL035586.
Member Since: July 3, 2005 Posts: 426 Comments: 128627
Quoting VAbeachhurricanes:


I wonder if Pottery would take those...

Only if they have been deflated, fed, and are house trained.
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Magnitude
6.0
Date-Time
Friday, May 20, 2011 at 00:46:16 UTC
Friday, May 20, 2011 at 09:46:16 AM at epicenter
Time of Earthquake in other Time Zones
Location
35.736°N, 140.981°E
Depth
26.2 km (16.3 miles)
Region
NEAR THE EAST COAST OF HONSHU, JAPAN
Distances
82 km (50 miles) SSE of Mito, Honshu, Japan
111 km (68 miles) E of TOKYO, Japan
126 km (78 miles) ENE of Yokohama, Honshu, Japan
133 km (82 miles) SE of Utsunomiya, Honshu, Japan
Location Uncertainty
horizontal +/- 13.4 km (8.3 miles); depth +/- 5.9 km (3.7 miles)
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that was only about 16 miles deep, offa the southern-more end of the island, too.

press- I ain't goin' there.... :)
Member Since: August 13, 2005 Posts: 166 Comments: 26039
Quoting PcolaDan:
Earthquake Information (Information on seismic intensity at each site)
Issued at 09:51 JST 20 May 2011

Occurred at(JST)Latitude(degree)Longitude(degree)Depth Magnitude Region Name
09:46 JST 20 May 2011 35.8N 141.3E 30 km 5.8 Ibaraki-ken Oki


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Quoting presslord:


I dunno aqua...but maybe you'll get a t-shirt


I want one. I'm a survivor. ; )
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6.0 just off Tokyo s east coast,this ones gonna cause damage imo
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Quoting aquak9:


whoa, I'm impressed.

Hey do they have blow-up pets, too?


I wonder if Pottery would take those...
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Quoting aquak9:
Man...I'm gonna be at work saturday till 11pm EST. Wonder if they'll pay me for my full shift.


I dunno aqua...but maybe you'll get a t-shirt

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Quoting Grothar:


Long time for a regular to be away.
It's possible he's just busy.
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Earthquake Information (Information on seismic intensity at each site)
Issued at 09:51 JST 20 May 2011

Occurred at(JST)Latitude(degree)Longitude(degree)Depth Magnitude Region Name
09:46 JST 20 May 2011 35.8N 141.3E 30 km 5.8 Ibaraki-ken Oki
Member Since: Posts: Comments:
Quoting KoritheMan:

I think I saw him sometime last month.


Long time for a regular to be away.
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There are now only 2 shopping Days Left till the Apocalypse.
Member Since: July 3, 2005 Posts: 426 Comments: 128627

Quoting Grothar:
I am really worried about GeoffWPB. I've been away and looked back at some old blogs. He hasn't been on for a long time. Anyone heard from him? He is always on.
I think I saw him sometime last month.
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Quoting Tropicsweatherpr:


Guam's NWS issued a Special Statement:

Link


Those are small island, too! That really blew up fast.
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Quoting presslord:

"Rapture"

Toe to toe
Dancing very close
Barely breathing
Almost comatose
Wall to wall
People hypnotised
And they're stepping lightly
Hang each night in Rapture

Back to back
Sacrailiac
Spineless movement
And a wild attack

Face to face
Sadly solitude
And it's finger popping
Twenty-four hour shopping in Rapture

Fab Five Freddie told me everybody's high
DJ's spinnin' are savin' my mind
Flash is fast, Flash is cool
Francois sez fas, Flashe' no do
And you don't stop, sure shot
Go out to the parking lot
And you get in your car and you drive real far
And you drive all night and then you see a light
And it comes right down and lands on the ground
And out comes a man from Mars
And you try to run but he's got a gun
And he shoots you dead and he eats your head
And then you're in the man from Mars
You go out at night, eatin' cars
You eat Cadillacs, Lincolns too
Mercuries and Subarus
And you don't stop, you keep on eatin' cars
Then, when there's no more cars
You go out at night and eat up bars where the people meet
Face to face, dance cheek to cheek
One to one, man to man
Dance toe to toe
Don't move too slow, 'cause the man from Mars
Is through with cars, he's eatin' bars
Yeah, wall to wall, door to door, hall to hall
He's gonna eat 'em all
Rapture, be pure
Take a tour, through the sewer
Don't strain your brain, paint a train
You'll be singin' in the rain
I said don't stop, do punk rock

Well now you see what you wanna be
Just have your party on TV
'Cause the man from Mars won't eat up bars when the TV's on
And now he's gone back up to space
Where he won't have a hassle with the human race
And you hip-hop, and you don't stop
Just blast off, sure shot
'Cause the man from Mars stopped eatin' cars and eatin' bars
And now he only eats guitars, get up!



Love Blondie.
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Quoting Grothar:


It looks like it is really getting strong fast. I posted the first image in post 220



Guam's NWS issued a Special Statement:

Link
Member Since: April 29, 2009 Posts: 75 Comments: 14308
that's a bad post, Eddy.
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ycd- page not found :(
Member Since: August 13, 2005 Posts: 166 Comments: 26039
Quoting Skyepony:


Maybe he'll show up with a story. Nothing on youtube yet other than preparing for the flood. Those flooded must be cut off still.


Japan has declared 98W a TD. Navy isn't there yet.




It looks like it is really getting strong fast. I posted the first image in post 220

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Linked to this BBC article just before i came here and got distracted:
http://www.bbc.co.uk/news/science-environment-134 57182
Oh yeah. It has to do with sea floor movement recorded after the 'quake off Japan.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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