More pre-season predictions of a very active Atlantic hurricane season
Hello again, it's Jeff Masters back again after a week away. Well, the past week was a wicked hot time to be in New England, where I was vacationing, and I certainly didn't expect to see 98° temperatures in Maine like I experienced! Fortunately, it's not hard to find cold water to plunge into in New England. Thankfully, the tropics were relatively quiet during my week away, and remain so today. There are no threat areas in the Atlantic to discuss at present, and none of the reliable computer models is forecasting tropical cyclone development over the next seven days. The NOGAPS model does show a strong tropical disturbance developing near the waters offshore of Nicaragua and Honduras this weekend, though. With not much to discuss in the present-day tropics, let's take a look at more pre-season predictions of the coming Atlantic hurricane season.
2010 Atlantic hurricane season forecast from Penn State
Dr. Michael Mann and graduate student Michael Kozar of Penn State University (PSU) issued their 2010 Atlantic hurricane season forecast on May 28. Their forecast utilizes a statistical model to predict storm counts, based on historical activity. Their model is predicting 19 to 28 named storms in the Atlantic, with a best estimate of 23 storms. The forecast assumes that record warm SSTs will continue in the Atlantic Main Development Region for hurricanes. Dr. Mann has issued two previous forecasts, in 2007 and 2009. The 2007 forecast was perfect--15 storms were predicted, and 15 storms occurred. The 2009 forecast called for 11.5 named storms, and 9 occurred (the 2009 forecast also contained the caveat that if a strong El Niño event occurred, only 9.5 named storms were expected; a strong El Niño did indeed occur.) So, the 2009 forecast also did well.
2010 Atlantic hurricane season forecast from the UK GloSea model
A major new player in the seasonal Atlantic hurricane season forecast game is here--the UK Met Office, which issued its first Atlantic hurricane season forecast in 2007. The UK Met Office is the United Kingdom's version of our National Weather Service. Their 2010 Atlantic hurricane season forecast calls for 20 named storms, with a 70% chance the number will range between 13 and 27. They predict an ACE index of 204, which is about double the average ACE index.
I have high hopes for the UK Met Office forecast, since it is based on a promising new method--running a dynamical computer model of the global atmosphere-ocean system. The CSU forecast from Phil Klotzbach is based on statistical patterns of hurricane activity observed from past years. These statistical techniques do not work very well when the atmosphere behaves in ways it has not behaved in the past. The UK Met Office forecast avoids this problem by using a global computer forecast model--the GloSea model (short for GLObal SEAsonal model). GloSea is based on the HadGEM3 model--one of the leading climate models used to formulate the influential UN Intergovernmental Panel on Climate Change (IPCC) report. GloSea subdivides the atmosphere into a 3-dimensional grid 0.86° in longitude, 0.56° in latitude (about 62 km), and up to 85 levels in the vertical. This atmospheric model is coupled to an ocean model of even higher resolution. The initial state of the atmosphere and ocean as of June 1, 2010 were fed into the model, and the mathematical equations governing the motions of the atmosphere and ocean were solved at each grid point every few minutes, progressing out in time until the end of November (yes, this takes a colossal amount of computer power!) It's well-known that slight errors in specifying the initial state of the atmosphere can cause large errors in the forecast. This "sensitivity to initial conditions" is taken into account by making many model runs, each with a slight variation in the starting conditions which reflect the uncertainty in the initial state. This generates an "ensemble" of forecasts and the final forecast is created by analyzing all the member forecasts of this ensemble. Forty-two ensemble members were generated for this year's UK Met Office forecast. The researchers counted how many tropical storms formed during the six months the model ran to arrive at their forecast of twenty named storms for the remainder of this hurricane season. Of course, the exact timing and location of these twenty storms are bound to differ from what the model predicts, since one cannot make accurate forecasts of this nature so far in advance.
The grid used by GloSea is fine enough to see hurricanes form, but is too coarse to properly handle important features of these storms. This lack of resolution results in the model not generating the right number of storms. This discrepancy is corrected by looking back at time for the years 1989-2002, and coming up with correction factors (i.e., "fudge" factors) that give a reasonable forecast.
The future of seasonal hurricane forecasts using global dynamical computer models is bright. Their first three forecasts have been good. Last year the Met Office forecast was for 6 named storms and an ACE index of 60. The actual number of storms was 9, and the ACE index was 53. Their 2008 forecast called for 15 named storms, and 15 were observed. Their 2007 forecast called for 10 named storms in July - November, and 13 formed. A group using the European Center for Medium Range Weather Forecasting (ECWMF) model is also experimenting with some promising techniques using that model. Models like the GloSea and ECMWF will only get better as increased computer power and better understanding of the atmosphere are incorporated, necessitating less use of "fudge" factors based on historical hurricane patterns. If human-caused climate change amplifies in coming decades, statistical seasonal hurricane forecasts like the CSU's may be limited in how much they can be improved, since the atmosphere may move into new patterns very unlike what we've seen in the past 100 years. It is my expectation that ten years from now, seasonal hurricane forecasts based on global computer models such as the UK Met Office's GloSea will regularly out-perform the statistical forecasts issued by CSU.
2010 Atlantic hurricane season forecast from Florida State University
Last year, another group using dynamical computer forecast models entered the seasonal hurricane prediction fray. A group at Florida State University led by Dr. Tim LaRow introduced a new model called COAPS, which is funded by a 5-year, $6.2 million grant from NOAA. This year, the COAPS model is calling for 17 named storms and 10 hurricanes. Last year's prediction by the COAPS model was for 8 named storms and 4 hurricanes, which was very close to the observed 9 named storms and 3 hurricanes.
Summary of 2010 Atlantic hurricane season forecasts
Here are the number of named storms, hurricanes, and intense hurricanes predicted by the various forecasters:
23 named storms: PSU statistical model
20 named storms: UKMET GloSea dynamical model
18.5 named storms, 11 hurricanes, 5 major hurricanes: NOAA hybrid statistical/dynamical model technique
18 named storms, 10 hurricanes, 5 intense hurricanes: CSU statistical model (Phil Klotzbach/Bill Gray)
17.7 named storms, 9.5 hurricanes, 4.4 intense hurricanes: Tropical Storm Risk (TSR), hybrid statistical/dynamical model technique
17 named storms, 10 hurricanes: FSU dynamical model
10 named storms, 6 hurricanes, 2 intense hurricanes: climatology
Only four hurricane seasons since 1851 have had as many as nineteen named storms, so 5 out of 6 of these pre-season forecasts are calling for a top-five busiest season in history. One thing is for sure, though--this year won't be able to compete with the Hurricane Season of 2005 for early season activity--that year already had five named storm by this point in the season, including two major hurricanes (Dennis and Emily.)
Tropical Storm Conson threatens the Philippines
Weather456 has an interesting post on why the Western Pacific typhoon season has been exceptionally inactive this year. It looks like we'll have out first typhoon of the Western Pacific season later today, since Tropical Storm Conson appears poised to undergo rapid intensification, and should strike the main Philippine island of Luzon as a Category 1 or 2 typhoon.
Next post
I'll have an update Wednesday.
Jeff Masters
Reader Comments
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I am still hearing you and others say that the Coast Guard passes the buck. That is disgraceful to the men and women of that service.
well said
Wouldn't have anything to do with him. He was one of those daguerreo types, if you know what I mean. :P
At least post a tropical image if you're going to insult someone. Only joking peoples. We should stay on topic.
850 is generally around 5000ft
Hallucinogenic plants? Cool!
Your family here, people don't like it, they can go elsewhere.
With Alex, I dunno. The flooding in places like Monterrey was quite surprising, and some of the post-storm deaths included some well-known public figures. They may actually consider it, depending on what happens the rest of this season.
yes sir
I havent ignored you. Why would i?
Well, one thing I've learned this summer on the blog is that Mexico would have to request the name be retired.
Don't forget to thank the little people on here. I was put on permanent ignore by someone here and I was complimenting them and they didn't realize it. I was sent a nasty WU mail. That is why I rarely compliment anybody. They might take is an an insult.
ouch. lol
but grothar, jokes is good. jokes is healthy. jokes clear our minds so we can think mighty thoughts and make mighty predictions. ....well... uh.... YOU can make mighty predictions.....
I agree it should be retired, but as it was discussed earlier, for a name to be retired the country where the most damage took place has to send in a request for the name to be retired, and from the past, Mexico has not done this, and chances are they will not do this with Alex either. Just my opinion.
Caribbean - Rainbow Loop
Looks to be headed for Caymans.
If I didn't get insulted by GeoffWPB at least once a night, I wouldn't come on here!
I enjoy a good joke. My mother said the same thing when I was born.
Your family here, people don't like it, they can go elsewhere.
Some people do the absolute best they know how. Some are very very bright in their own way. Maybe some people are weather geniuses and maybe they cannot spell. Maybe we should respect them and remember, some people are are gifted in certain ways, some people are well respected and very sensitive.
Messing with Taz will get you reported to Admin and possibly banned.
Calling Dr. Fine....
Evening Taz -- that's too funny
You forgot Dr. Howard and Dr. Howard :)
For Duty and Humanity!!!
Finally learned how to post an image, he, Geoff. But why the Norwegian version? Trying to be funny. LOL By the way, if you look at Geoffs globe image. mandag means Monday.
Waves do look interesting, though
shhhhh dont give JFV any new names PLZs
I'm not liking the feeling of the persistent low... though I suppose it has the benefit of cloudcover keeping nearby waters from heating massively....
Sorry, last time LOL. Back on topic.
I've never understood the fascination with which names get retired. Year after year people spend hours & hours going over which one should be retired, why, etc? Maybe someone could explain.
(serious question -- not w** remark)
That is a cool color scheme.
I hope he doesn't have cable or satellite... 1000's of channels to choose from.
I think it is a bit like discussing who should be in the hall of fame in sports.
I can just about bet that if Alex had caused similar death and destruction on US soil this would not even be a subject of discussion. So you may be right.
Did not know about Stan's retirement, Thanks. Took a quick refresher course!
Following the severe damage and extensive loss of life in Stan's wake, the World Meteorological Organization retired the name Stan from the circulating list of Atlantic hurricane names. For the 2011 season, Stan was replaced by Sean.[10] Upon being retired, Stan was the first tropical cyclone in the Atlantic basin beginning with the letter "S" to do so since 1954. It was also the fourth of five Category 1 hurricanes to have its name retired.[11]
Stan-Wiki
(Theme from Jaws playing)
That short subject flick...Men In Black...was nominated for an Academy Award!
BP took a major step this weekend. I hope they get it working without risking further damage to the down-hole casing. This is pretty much the fix that was recommended during the first week by a subcontractor (I can't remember if it was Boots&Coots, or Wild-well that recommended it).
Bourbon is over by the ice bucket. help yourselves. Chicklet, can I mix you a White Russian?
Hmmmmmmmmm... it is kinda freaky
On the retirements, all I know is the countries most affected are the ones to make the call. The US seems to make the most calls, IMO and I think that's because US calls on the basis of emotional and economic impact while others tend to do so on the basis of loss of life. I think also there's a sense that a second hurricane bearing a similar name is unlikely to make landfall in the same place more than once, though I don't know how much impact THAT has....
This could be a really good day!!! With a lot of hard work in front of all of us!
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