Early 2011 Atlantic Hurricane Season Forecasts
Hi everybody, this is Dr. Rob Carver filling in for Dr. Masters.
A continuation of the pattern of much above-average Atlantic hurricane activity we've seen since 1995 is on tap for 2011, according to the latest seasonal forecast issued April 6 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). They are calling for 16 named storms, 9 hurricanes, and 5 intense hurricanes. An average season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. The new forecast is nearly identical to their forecast made in December, which called for 17 named storms, 9 hurricanes, and 5 intense hurricanes. Only six seasons since 1851 have had as many as 17 named storms; 19 seasons have had 9 or more hurricanes. The 2011 forecast calls for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (48% chance, 31% chance is average) and the Gulf Coast (47% chance, 30% chance is average). The Caribbean is forecast to have a 61% chance of seeing at least one major hurricane (42% is average.) Five years with similar pre-season November atmospheric and oceanic conditions were selected as "analogue" years that the 2011 hurricane season may resemble: 2008, 1999, 1996, 1955, and 2006. The first four years listed all had neutral to La Niña SST's during hurricane season, while 2006 had El Niño SST's. The average activity for these years was 12.6 named storms, 7.8 hurricanes, and 4.8 major hurricanes.
This year, the forecasters have introduced a new statistical model for their April forecasts. There are four components in this model:
1. Average sea-level pressure in March around the Azores in the subtropical Atlantic.
2. The average of January through March sea-surface temperatures (SST's) in the tropical Atlantic off the coast of Africa.
3. Average sea-level pressure in February and March for the southern tropical Pacific ocean west of South America.
4. Forecasts of September's SST in the tropical Pacific using a dynamical model from the European Centre for Medium-Range Weather Forecasts (ECMWF)
The first two components are loosely linked together. Statistical studies have shown that a weaker subtropical high near the Azores, combined with warmer SST's off the coast of Africa in March are associated with weak winds near the surface and aloft from August to October. This decrease in wind speeds reduces wind shear which can disrupt forming storms. These March conditions also are associated with warmer SST's in August to October, which is also favorable for more tropical storms. For this forecast, the first component is strongly favorable for increased hurricane activity, while the second component is weakly negative.
The last two components represent the changes in sea-surface temperature and sea-level pressure that are the El Niño-Southern Oscillation (ENSO). Briefly speaking, El Niño conditions (warm sea-surface temperatures) are not favorable for Atlantic hurricanes. For more info on ENSO and hurricanes, Jeff has this article.
Using the ECMWF model as guidance (see Figure 1), the CSU group believes that SST's in the tropical Pacific will be neutral (less than 0.5°C from normal). This would have a small negative effect on hurricane activity. However, the tropical Pacific sea-level pressure shows that the atmosphere looks like a La Niña event is still going on. This is strongly favorable for Atlantic hurricane activity in the CSU group's model.
Figure 1. Forecasts of El Niño conditions by 20 computer models, made in March 2011. The ECMWF forecast used by the CSU group is represented by the dark orange square. The forecasts for August-September-October (ASO) show that 5 models predict El Niño conditions, 7 predict neutral conditions, and 5 predict a weak to moderate La Niña. El Niño conditions are defined as occurring when sea surface temperatures in the Equatorial Pacific off the coast of South America ( the "Niño 3.4 region) rise to 0.5°C above average (top red line). La Niña conditions occur when SSTs in this region fall to 0.5°C below average. Image credit: Columbia University.
How accurate are the April forecasts? While the formulas used by CSU do well in making hindcasts--correctly modeling the behavior of past hurricane seasons--their April hurricane season forecasts have had no skill in predicting the future. This year's April forecast is using a new system and has not yet produced a verified forecast. The scheme used in the past three years successfully predicted active hurricane seasons for 2008 and 2010, but failed to properly predict the relatively quiet 2009 hurricane season. A different formula was used prior to 2008, and the April forecasts using that formula showed no skill over a simple forecast using climatology. CSU maintains an Excel spreadsheet of their forecast errors ( expressed as a mathematical correlation coefficient, where positive means a skilled forecast, and negative means they did worse than climatology) for their their April forecasts. For now, these April forecasts should simply be viewed as an interesting research effort that has the potential to make skillful forecasts. The next CSU forecast, due by June 1, is the one worth paying attention to. Their early June forecasts have shown considerable skill over the years.
Figure 2. Accuracy of long-range forecasts of Atlantic hurricane season activity performed by Phil Klotzbach and Bill Gray of Colorado State University (colored squares) and Tropical Storm Risk, Inc. (colored lines). The CSU team's April forecast skill is not plotted, but is less than zero. The skill is measured by the Mean Square Skill Score (MSSS), which looks at the error and squares it, then compares the percent improvement the forecast has over a climatological forecast of 10 named storms, 6 hurricanes, and 2 intense hurricanes. TS=Tropical Storms, H= Hurricanes, IH=Intense Hurricanes, ACE=Accumulated Cyclone Energy, NTC=Net Tropical Cyclone Activity. Image credit: TSR.
2011 Atlantic hurricane season forecast from Tropical Storm Risk, Inc.
The British private forecasting firm Tropical Storm Risk, Inc. (TSR), issued their 2011 Atlantic hurricane season forecast on April 5. They are also calling for a very active year: 14. 2 named storms, 7.5 hurricanes, and 3.6 intense hurricanes. We would round that to 14 named storms, 8 hurricanes, and 4 intense hurricanes. This compares to their forecast issued in December of 15.6 named storms, 8.4 hurricanes, and intense hurricanes. TSR predicts a 55% chance of an above-average hurricane season, 28% chance of a near-normal season, and only a 17% chance of a below normal season. TSR bases their April forecast on predictions that sea surface temperatures this fall in the tropical Atlantic will be above about 0.08°C above average, and trade wind speeds will be about 0.2 m/s slower than average. The decrease in the trade wind speeds is favorable for enhanced hurricane activity, while the forecast SST's are expected to be neutral for hurricane activity.
TSR puts their skill level right next to the forecast numbers: 13% skill above chance at forecasting the number of named storms, 11% skill for hurricanes, and 10% skill for intense hurricanes. That's not much skill, and really, we have to wait until the June 1 forecasts by CSU, NOAA, and TSR to get a forecast with reasonable skill.
Rob's critiques of the April forecasts
I have to note that Jeff and I wrote this article together. He wrote the general framework before the forecasts were issued, while I wrote the details based on the actual forecasts. So the preceding text is a joint production. However, I have a few observations to make that are my responsibility alone.
First, I am disappointed that the CSU group has changed forecast models only after three seasonal forecasts. This makes it very difficult to assess the skill of the current forecast using past performance. This is very important for forecast users, and they do it everyday. For example, I tend to discount a forecast of rain if it comes from a source that over-forecasts rain (The boy who cried wolf problem).
In the documentation that came with the April forecast, the CSU group argue that the hindcasts show the new forecast model has skill. However, I think hindcasts are a poor substitute for real forecasts in understanding the skill of a statistical forecast model, like that of the CSU's group. As Jeff noted, the previous forecast model did well with the hindcasts and yet had mixed results with the actual forecasts. This does not give me confidence that the new forecast model will be superior to the previous model.
From a philosophical viewpoint, I am inherently cautious about statistical forecast models like the one used by the CSU group. Essentially, they look at what happened in the past and use that to predict the future. However, for making forecasts, we assume that the relationships in space and time between the predictors (such as the average March sea-level pressure around the Azores) and the predictands (Atlantic hurricane activity) does not change as we move forward in time. In a world with climate change, that's a tricky assumption to make.
In any event, it is customary in the meteorological community to continue running older forecast guidance models after the introduction of newer models. This allows forecasters and forecast users to leverage their knowledge of the forecast skill of the older model and gain insight into the forecast skill of the new model. The CSU group really should have included the forecast from the previous statistical forecast system in this forecast.
I am uneasy with some of the methodology choices made in implementing the forecast model. Data for the first three predictors was obtained from the Climate Forecast System Reanalysis (CFSR), NOAA's newest and most advanced reanalysis product. However, CFSR data for 2010 and 2011 has not been released yet, so the CSU group used NCEP/NCAR Reanalysis (NNR), NOAA's first-generation reanalysis, to fill in the gaps. Due to differences in design, resolution, etc., CFSR and NNR can have different depictions of the state of the atmosphere. So using NNR's March 2011 average SLP instead of CFSR's could alter the forecast in unexpected ways. It would be interesting to see how CFSR's 2010-2011 data changes the results.
In any event, we will have to wait and see what the Atlantic hurricane season of 2011 brings.
Reader Comments
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I'll be there! Teaching, in fact...
yea about 50 years ago, oh wait, we did not have computers back then
You mean it stood out because the temperatures were in the low 20's or you are in your low 20's????
All I want to know is where do you get a copy of my high school picture?? LOL
The internet is a wonderful thing. Wow, I thought it was a old college photo from a frat party or something
ehhh its Accuweather, I'm not sure if you wanna go to them for valid scientific information. They would be much better at making weather disaster movies for hollywood.
Over 10 people killed and over 100 injured in severe sand storms in Germany.
The sand storms blocked visibility on motorways and traffic which is not speed restricted on some motorways was involved in pile ups.
Apparently these sandstorms are not uncommon in Germany. Makes you wonder why they don't have speed limits? That may affect fast car sales, of course!!
Already had 90L in March.
The National Hurricane Conference - I am moderating two panels:
Crisis Communications: Case studies in Successful public outreach
Reaching out: Social Vulnerability in emergency public information
And, I'll be teaching in:
How social media is being used today by Emergency Management and media in disasters.
Should be fun...
Im well aware of that,,tyvm.
I was just about to post this, can't believe you mentioned it.
Who told????
By Elizabeth Landau, CNN
April 8, 2011 2:36 p.m. EDT
(CNN) -- In the search for answers to some of the most mysterious and fundamental questions about the the universe, Europe's $10 billion particle-smashing Large Hadron Collider has been hogging the spotlight in recent years.
Suddenly, this week, physics enthusiasts' eyes turned to Tevatron, a much smaller and less powerful particle accelerator in Batavia, Illinois, that is scheduled to be shut down for good after September. And, depending on what happens with the budget crisis on Capitol Hill, it could be even sooner.
At Tevatron, part of the Fermi National Accelerator Laboratory (Fermilab), scientists said they may have found evidence of a particle never observed before. That would mean a brand new building-block of matter would be added to what physicists know about the universe.
But the keyword is "may" -- there's a 1 in 1,000 chance that it's just a fluke of statistics. In the coming weeks and months, additional data from Tevatron's detectors and the Large Hadron Collider will probably deliver a more definitive answer about whether indeed a new particle has been discovered.
"If it is true, then it's of course very important. But there's a big if," said Csaba Csaki, associate professor of physics at Cornell University, who was not involved in the experiment.
What they're looking for
Research at particle accelerators often addresses big questions that get at the very nature of existence: Why do we -- and everything around us -- have mass?
One theory that has gained a lot of attention is that there is a particle called the Higgs boson that has this power of giving particles mass. For that reason it has been deemed the "God particle" in popular culture.
faster and faster we go
Please remind them that all forms of media must be used during a disaster. A lot of people are without electricity and there are still a lot of poor folks who have no computers or iphones and the elderly who do not want or can't afford such devices.
2011 National Hurricane Conference
April 18-22|Hyatt Regency Atlanta|Atlanta, GA
The nation's forum for education and professional training in hurricane and disaster preparedness!
Purpose of the Conference
The primary goal of the National Hurricane Conference is to improve hurricane preparedness, response, recovery and mitigation in order to save lives and property in the United States and the tropical islands of the Caribbean and Pacific. In addition, the conference serves as a national forum for federal, state and local officials to exchange ideas and recommend new policies to improve Emergency Management.
To accomplish these goals, the annual conference emphasizes:
* Lessons Learned from Hurricane Strikes.
* State of the art programs worthy of emulation.
* New ideas being tested or considered.
* Information about new or ongoing assistance programs.
* The ABC's of hurricane preparedness, response, recovery and mitigation -- in recognition of the fact that there is a continual turnover of emergency management leadership and staff.
Good ole seabreeze looking good today
Fugate in 2004 was about the best I've seen.
Guten Abend Grothar.
I was just about to post it then I saw that you and Plaza had already beaten me to it. I watched the video and I could give you a summary of what is said in there.
"State of emergency on the A19 near Rostock. More than 50 vehicles were involved in large scale collisions, among them a road tanker. Several people were killed and many badly injured.
An unusual weather phenomenon presumably caused the multi-vehicle collision. According to eye-witnesses, hurricane force gusts raised dust and a tornado-like sand storm formed. This reduced visibility to less than 1 meter. The bad conditions led to collisions on roadways in both directions. Several vehicles were set ablaze.
A large contingent of emergency services, including several helicopters, arrived at the scene and the state of emergency was declared."
On the German yahoo site I found more detailed information. The article speaks of several collisions killing 8 and severely injuring 27 people and over 80 vehicles were involved. In the worst collision 17 cars and 3 trucks burnt out completely, one of them allegedly carried liquid carbon hydride but this has not yet been confirmed.
Actually we did - not desk-tops, however.
I started working with computers 50 years ago, 01 May 1961.
I was on I-25 northbound near the Colorado-Wyoming border once when visibility went from nearly unlimited to only a few meters in a matter of seconds due to a small, wind-driven snowstorm. Traffic was moving about 70mph at the time. It's a scary situation and hard to know what exactly to do. I slowly let off the gas and shifted my gaze back and forth between the front windshield and the rear view mirror, ready to dash into the emergency lane at any point if I saw somebody approaching from behind.
I'm not sure if letting off the gas and coasting to a slower speed was the right action, but to anyone unfortunate enough to experience this... PLEASE do not slam on your breaks!! That's perhaps one of the worst things you can do.
Thoughts and prayers to those in Germany who were in the wrong place at the wrong time...
You should have seen it on the Spanish news, they were piled up like they were in the tsunami!! It is Germany's version of tidal insanity, lots of people rushing off for the weekend with no vision on a motorway, in a sandstorm with virtual zero vision. Add to that no speed limits that I know of.
Apparently in a howling, screaming northerly type gale and no attempt to drive with anything like a safe stopping distance. Lots of fires too after impacts.
I got my driver's license in Germany and I know we were not given any instructions how to act in events like this. Sandstorms of this kind are very unusual in Germany. We sometimes get some sahara dust crossing the Alps but it usually only leaves a yellow dust layer on parked cars.
Here in the UK I wouldn't expect any sandstorms, the climate is usually a lot wetter than in East Germany where this event took place. This said, we've had the driest March since 1944 so never say never...
+1,000,000
Right! It's been raining for several hours in the SP, Costa Rica. The skies are really cloudy at the moment, and the rain doesn't seem like it is gonna stop any time soon.What do u think is causing so much moisture? I can tell from exeperience,this is not normal in April. It is more like a "transitional" month from dry season to RS.
Anyways I like it!!!
Of course, as with my example, this sort of situation can happen with snow squalls as easily as it can happen with dust.
I've experienced many other less intense scenarios like the one I mentioned due to what we call "ground blizzards"... basically, wind-driven snow (on the ground from previous storms) will blow across the road on an otherwise clear day and can reduce visibility to near nil. I've seen many folks slam on their breaks when this happens and, while I understand the instinct, I am constantly amazed that people forget about the cars behind them (if you can't see, that means people can't see you).
I'm currently watching the German news, truly horrible pictures. The number of victims has increased to 10, all burnt in their cars. Survivors said they had no chance whatsoever since conditions deterioriated within seconds.
It is labeled as the worst collision on record in the state of Mecklenburg-Vorpommern. I think it is the first time that the state of emergency was declared due to a massive traffic accident.
Joe "worst long-range forecaster on Earth" Bastardi predicted 16 to 18 tropical storms in total. Not 20 Link
YEAH sth might be brewing!
You can say that again!
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