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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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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Man...I'm gonna be at work saturday till 11pm EST. Wonder if they'll pay me for my full shift.
Member Since: August 13, 2005 Posts: 163 Comments: 25732
Quoting eddy12:
The world ends saturday I better go find some hookers and blow oh yea and whiskey to wash out the taste of weed and hooker spit
is that one of them blow up hookers you plan on picking up
Member Since: July 15, 2006 Posts: 169 Comments: 53296
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.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting Grothar:


Doesn't PlazaRed live in Southern Spain? Hope he is OK. Spain has been experiencing some strange weather.


Think you may be right, and I think it may be the Andalusia region.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting PcolaDan:


I am not a crook.


HA. I knew you would get it.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
deleted.
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting Grothar:


Well, I heard 18 1/2 minutes were missing from it. LOL



I am not a crook.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting aquak9:


whoa, I'm impressed.

Hey do they have blow-up pets, too?

This is gettin' kinkay!!
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Member Since: August 13, 2007 Posts: 0 Comments: 10479
Quoting Grothar:


Well, I heard 18 1/2 minutes were missing from it. LOL



whoa, I'm impressed.

Hey do they have blow-up pets, too?
Member Since: August 13, 2005 Posts: 163 Comments: 25732
290. Skyepony (Mod)
Quoting Grothar:


Doesn't PlazaRed live in Southern Spain? Hope he is OK. Spain has been experiencing some strange weather.


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.


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Quoting DDR:
The rainy is here thanks to that Tropical wave,just 6 mm at my location but its just the beginning.


It doesn't look like much, but they can drop a lot of rain sometimes. Hope it moves our way.

Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting PcolaDan:


THEY SAID THEY WOULD DESTROY THE TAPE!!!!!

Hi Gro. :)


Well, I heard 18 1/2 minutes were missing from it. LOL

Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting Skyepony:
More floating cars..

Situation Update No. 1
On 19.05.2011 at 16:01 GMT+2

Torrential rain has caused flash floods in southern Spain, killing an elderly woman and sending cars floating down the streets of one town. National Spanish Television on Thursday showed a river of water gushing through the streets of Canete de las Torres town in the Andalusia region and cars piled on top of one another. About 150 houses were evacuated, and TV footage showed people sweeping water out of their damaged homes. The body of an 85-year-old woman was found in a stream in the town hours after the heavy rains began Wednesday. The regional government says the south-central province of Cordoba was the worst hit.


Doesn't PlazaRed live in Southern Spain? Hope he is OK. Spain has been experiencing some strange weather.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting Grothar:


What would be more embarrassing is if you walk in one of them and they say, "Hi, Dan"


THEY SAID THEY WOULD DESTROY THE TAPE!!!!!

Hi Gro. :)
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting PcolaDan:


I can see us all going into the...uh...store and buying one.

"Really, a bunch of us are going to fill them with helium and let them fly."

"Uh huh, sure"

"No, REALLY"

"Yea, whatever."

"SERIOUSLY, I wouldn't buy something like this otherwise."

"Whatever you say, just pay for it, okay."

"NO, REALLY, I MEAN IT!!!!! Ahhhhh, never mind. Wait, is that a CAMERA an the wall there??? AM I BEING FILMED???? Uhhhh, I gotta go."


What would be more embarrassing is if you walk in one of them and they say, "Hi, Dan"
Member Since: July 17, 2009 Posts: 69 Comments: 25345
282. DDR
The rainy is here thanks to that Tropical wave,just 6 mm at my location but its just the beginning.
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Quoting WaterWitch11:


i couldn't even begin to fathom a 10.2


If it is off the coast of New Zealand, that would be about 16,000 fathoms.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
280. Skyepony (Mod)
More floating cars..

Situation Update No. 1
On 19.05.2011 at 16:01 GMT+2

Torrential rain has caused flash floods in southern Spain, killing an elderly woman and sending cars floating down the streets of one town. National Spanish Television on Thursday showed a river of water gushing through the streets of Canete de las Torres town in the Andalusia region and cars piled on top of one another. About 150 houses were evacuated, and TV footage showed people sweeping water out of their damaged homes. The body of an 85-year-old woman was found in a stream in the town hours after the heavy rains began Wednesday. The regional government says the south-central province of Cordoba was the worst hit.
Member Since: Posts: Comments:
279. DDR
From the Trinidad & Tobago met office

OFFICIAL STATEMENT

Following a very productive (rainfall wise) early 2011 dry season which eventually normalized, the 2011 wet season has started as if on schedule, approximately five (5) days after its last year’s counterpart.

And we are in for what could be a rather interesting wet season!
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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.


Yes,during my lurking time in the past two years,those debates have been very educational for those of us who dont have the expertise.
Member Since: April 29, 2009 Posts: 75 Comments: 14004
Quoting Neapolitan:
A guy over at Daily Kos had a great idea: we can all pitch in and buy a bunch of blow-up dolls, fill them full of helium, dress them up in Sunday clothes, and release them from various locations around town at Zero Hour. (Maybe to strains of "Up, Up, & Away".)

Artist's conception:
Appropriate tropical weather-related image.

We can even strap smoke canisters to some of them so they'll look like slow-moving rockets. Rapture rockets.

Anybody with me?


I can see us all going into the...uh...store and buying one.

"Really, a bunch of us are going to fill them with helium and let them fly."

"Uh huh, sure"

"No, REALLY"

"Yea, whatever."

"SERIOUSLY, I wouldn't buy something like this otherwise."

"Whatever you say, just pay for it, okay."

"NO, REALLY, I MEAN IT!!!!! Ahhhhh, never mind. Wait, is that a CAMERA an the wall there??? AM I BEING FILMED???? Uhhhh, I gotta go."
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting KEEPEROFTHEGATE:
yep so they say a big one too a 10.2 offshore of new zealand sometime near 6:00pm or just after


i couldn't even begin to fathom a 10.2
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Quoting EYEStoSEA:


Yep, had lurked since 2005, and finaly got up the nerve to post something, and Grothar came thru....made me feel welcome, that's why I'm so partial to the ole goat!!

LOL
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting Neapolitan:
A guy over at Daily Kos had a great idea: we can all pitch in and buy a bunch of blow-up dolls, fill them full of helium, dress them up in our Sunday best, and release them from various locations around town at Zero Hour. (Maybe to strains of "Up, Up, & Away".)

Artist's conception:
Appropriate tropical weather-related image.

We can even strap smoke canisters to some of them so they'll look like slow-moving rockets. Rapture rockets.

Anybody with me? ;-)

I LIKE it!
And it will be great for business in those places that sell inflatible ladies and stuff...
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting pottery:

It shows that you have Great Fortitude, to have stayed after THAT experience...


Yep, had lurked since 2005, and finaly got up the nerve to post something, and Grothar came thru....made me feel welcome, that's why I'm so partial to the ole goat!!
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I like Drak, but he has a tendency to let his ego get the best of him. Always has a quality analysis however :)
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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.b oth very brightB.


Amen to that!
Member Since: October 24, 2005 Posts: 0 Comments: 24023
A guy over at Daily Kos had a great idea: we can all pitch in and buy a bunch of blow-up dolls, fill them full of helium, dress them up in Sunday clothes, and release them from various locations around town at Zero Hour. (Maybe to strains of "Up, Up, & Away".)

Artist's conception:
Appropriate tropical weather-related image.

We can even strap smoke canisters to some of them so they'll look like slow-moving rockets. Rapture rockets.

Anybody with me?
Member Since: November 8, 2009 Posts: 4 Comments: 13456
Quoting pottery:
This blog is Hysterical tonight !
I Love it.

I'm in and out for a bit, as I am attempting to turn a Filet of Swordfish into something that is edible...
It's in the Grill right now.
Smelling good.
And while we await THAT Rapture, CHEERS!


I hope you removed the "sword" part. Turning that on a grill could be dangerous (and painful)
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Quoting EYEStoSEA:


and YOU were the first person to quote and respond to me...how bout that!

It shows that you have Great Fortitude, to have stayed after THAT experience...
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting Tropicsweatherpr:
There is one person that I haven't seen here for a while,and that is Drakoen.Hopefully,he comes soon,although Levi,Hurricane23,TropicalAnalystwx13 and others do a good job doing analysis of the factors.


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.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
This blog is Hysterical tonight !
I Love it.

I'm in and out for a bit, as I am attempting to turn a Filet of Swordfish into something that is edible...
It's in the Grill right now.
Smelling good.
And while we await THAT Rapture, CHEERS!
Member Since: October 24, 2005 Posts: 0 Comments: 24023
Quoting EYEStoSEA:


and YOU were the first person to quote and respond to me...how bout that!


For real?
Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting presslord:



wrong place at the wrong time
we already got the sunday morning headlines ready just in case lol


this is not real this is a parody
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Quoting presslord:
Homemade dams holding back flood watersLink


Wow... never seen anything like that.
Member Since: March 26, 2006 Posts: 44 Comments: 1520
Quoting Grothar:


TD was one of the first people with whom I spoke when I started on the blog. I wish him luck.


and YOU were the first person to quote and respond to me...how bout that!
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Quoting EYEStoSEA:


Havent seen Futuremet, but Tornadodude stopped by last night. He is finally a real "chaser" He's with MIDSCAR....I watch them on Tornadovideos.Net. A good team to be with.


TD was one of the first people with whom I spoke when I started on the blog. I wish him luck.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
There is one person that I haven't seen here for a while,and that is Drakoen.Hopefully,he comes soon,although Levi,Hurricane23,TropicalAnalystwx13 and others do a good job doing analysis of the factors.
Member Since: April 29, 2009 Posts: 75 Comments: 14004
258. Skyepony (Mod)
NOAA expects a below normal Central Pacific
hurricane season

May 18, 2011

NOAA’s Central Pacific Hurricane Center today announced that projected climate conditions point to a below normal hurricane season in the Central Pacific Basin this year.

NOAA issued its outlook at a news conference today to urge Hawaii residents to be fully prepared for the onset of the hurricane season, which begins on June 1.

“Now is the time to prepare for the hurricane season in the central Pacific,” said Ray Tanabe, director of the Central Pacific Hurricane Center, part of the U.S. National Weather Service. “Last year we had a quiet season, but it’s definitely not time to let our guard down.”

The seasonal hurricane outlook is produced in collaboration with NOAA’s Climate Prediction Center. For 2011, the outlook calls for a 70 percent chance of a below normal season, a 25 percent chance of a near normal season, and a five percent chance of an above normal season. We expect 2-3 tropical cyclones to affect the central Pacific this season. An average season has 4-5 tropical cyclones, which include tropical depressions, tropical storms, and hurricanes.
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hey anyone notice a spin approaching Jamaica??
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256. Skyepony (Mod)
NOAA predicts below normal Eastern Pacific hurricane season

May 19, 2011

NOAA’s Climate Prediction Center today announced that climate conditions point to a below normal hurricane season in the Eastern Pacific this year. The outlook calls for a 5 percent probability of an above normal season, a 25 percent probability of a near normal season and a 70 percent probability of a below normal season.

Allowing for forecast uncertainties, seasonal hurricane forecasters estimate a 70 percent chance of 9 to 15 named storms, which includes 5 to 8 hurricanes, of which 1 to 3 are expected to become major hurricanes (Category 3, 4 or 5 on the Saffir-Simpson Hurricane Wind Scale).

An average Eastern Pacific hurricane season produces 15 to 16 named storms, with eight to nine becoming hurricanes and four becoming major hurricanes. The Eastern Pacific hurricane season runs from May 15 through Nov. 30, with peak activity from July through September.

The main climate factors influencing this year’s Eastern Pacific outlook are:

* Ongoing conditions, such as increased wind shear, that have been suppressing eastern Pacific hurricane seasons since 1995, and
* A high likelihood of ENSO-neutral conditions (no El Niño or La Niña) during the peak months (July-September) of the season, but with lingering La Niña impacts into the summer.

“Regardless of this outlook, NOAA urges people in the Eastern Pacific to prepare for the 2011 hurricane season and remain vigilant throughout the season – it only takes one hurricane to cause a lot of damage and loss of life,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, part of the U.S. National Weather Service.
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Quoting Grothar:
Has anyone heard from Futuremet?


Havent seen Futuremet, but Tornadodude stopped by last night. He is finally a real "chaser" He's with MIDSCAR....I watch them on Tornadovideos.Net. A good team to be with.
Member Since: Posts: Comments:
Homemade dams holding back flood watersLink
Member Since: August 13, 2007 Posts: 0 Comments: 10479
Quoting Grothar:
Has anyone heard from Futuremet?


Not seen him.
Member Since: July 6, 2010 Posts: 113 Comments: 31451

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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.