More pre-season predictions of a very active Atlantic hurricane season

By: Dr. Jeff Masters , 3:02 PM GMT on July 12, 2010

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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

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A general statement to all my friends here on WU and the little trolls parading around.

We are all family, we respect one another here, we talk tropical weather during Hurricane Season.

Many folks add much here, we have real meteorologists, tropical weather specialists, meteorology students, several very astute young folk under 18. We have folks who love weather here and share and learn.

Those who want to disrespect my family will be reported and Admin will deal with you, as they see fit.

Thanks!
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Quoting Grothar:
Sorry dragonfly, but my image has scarier color.



The Saw the movie version of the smiley face. That actually could be appropriate .. Hurricanes do look like buzz saws...
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anyone still think we'll see 15 plus storms this season ??? been a quiet July so far
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CAUTION - 20 mb animation .... you're about to enter THE spin zone.

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Those are from the St. Olaf Satellite Service.
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Quoting Dakster:


I hope he doesn't have cable or satellite... 1000's of channels to choose from.



LOL
Member Since: May 21, 2006 Posts: 5091 Comments: 114696
Geez, EDL, it's getting more defined, if anything! And why is that other Twave still there????
Member Since: October 25, 2005 Posts: 19 Comments: 21392
Its not contained yet, they're just lowering the cap onto it.
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1197 LOL!!!! "Wall-Mart marketing plan..."

Could be "The spirit of the cape verde season" smiling at the favorable conditions this season... (shudder, bad thought that was...)
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Quoting GeoffreyWPB:


That short subject flick...Men In Black...was nominated for an Academy Award!


it sure was. one of their best!

g'nite :)
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1204. Grothar
Sorry dragonfly, but my image has scarier color.

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1203. Patrap
Skandi_ROV 2

Oil Spill ROV Windows
Member Since: July 3, 2005 Posts: 420 Comments: 127512
The numbers don't seem right with cyclone conson, the 12 hour do not increase the storms intensity even at its rate of speed it will be just offshore over 30 to 32 degree water temps, in a low wind shear environment for the time being and no real land interaction, hmm i'm no pro by any means but i think i would consider fueling up another plane to fly in there before 12 hours, some of those people may need to get to higher ground and soon anyone have a bead on this storm?
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Quoting Baltimorebirds:
They capped it?.Yes.


This could be a really good day!!! With a lot of hard work in front of all of us!
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Quoting zoomiami:
Hi Baha -- I'm with you on the Sudoku, not much going on.

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)
Hey, zoo, just saw you came on. I'm enjoying the last few hours of the Independence holiday... barely hit a lick the entire time.... lol

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....
Member Since: October 25, 2005 Posts: 19 Comments: 21392
1198. fishcop
Good evening fellow weather nerds - muggy and still in Grand Cayman. Africian coast looks like its picking up
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Look the Earth is happy now that the Oil spill got capped. or Walmart Starts a new unprecedented marketing plan of sky writing over Africa??? Or it could be the Cape Verde Season give us a smile..

Hmmmmmmmmm... it is kinda freaky

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Good evening all,

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?
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Quoting fatlady99:


For Duty and Humanity!!!


That short subject flick...Men In Black...was nominated for an Academy Award!
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1193. Grothar
Quoting CybrTeddy:
Grothar and StormW investigating Climate Change.


Sorry, last time LOL. Back on topic.


(Theme from Jaws playing)
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1192. beell
Quoting BahaHurican:
They did request for Stan that same year to be retired, though. There was some very bad flooding with Stan and subtantial loss of life.

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.


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
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1191. bappit
Quoting zoomiami:
Hi Baha -- I'm with you on the Sudoku, not much going on.

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)

I think it is a bit like discussing who should be in the hall of fame in sports.
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1190. Dakster
Quoting Tazmanian:




shhhhh dont give JFV any new names PLZs


I hope he doesn't have cable or satellite... 1000's of channels to choose from.
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1189. bappit
Quoting MiamiHurricanes09:
Hehehehehehehehehe...


That is a cool color scheme.
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Hi Baha -- I'm with you on the Sudoku, not much going on.

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)
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Grothar and StormW investigating Climate Change.


Sorry, last time LOL. Back on topic.
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Quoting Chicklit:
There is still a Bahama Blob.

Caribbean - Rainbow Loop

Looks to be headed for Caymans.
Chick, I think this is the rainiest July 1-15 we've had in a decade or two, maybe even 3. Normally it's super dry here, with persistent high, easterlies at 10 - 25 mph, and the occasional p.m. thunderstorm.

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....
Member Since: October 25, 2005 Posts: 19 Comments: 21392
Quoting ElConando:
1164. WFOR comes next.




shhhhh dont give JFV any new names PLZs
Member Since: May 21, 2006 Posts: 5091 Comments: 114696
1184. Grothar
Quoting GeoffreyWPB:


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
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Quoting GeoffreyWPB:


You forgot Dr. Howard and Dr. Howard :)


For Duty and Humanity!!!
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Quoting fatlady99:


Calling Dr. Fine....


You forgot Dr. Howard and Dr. Howard :)
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Quoting Tazmanian:
1132. FLdewey 1:53 AM GMT on July 13, 2010 Hide this comment.

Quoting Tazmanian:
you guys skip right ovee commet 1096



We were trying not to notice you can't even spell NOSE. ;)



POOF



would any one like too joine him???



i will not have none of that


Evening Taz -- that's too funny


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Quoting ElConando:
1164. WFOR comes next.
We've already had Local 10, CBS 4, and now 7 news. Nevermind, I got the comment. LMAO!
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These African waves have been like plop-plop…fizz-fizz once they hit the water.
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Quoting Grothar:


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.


Calling Dr. Fine....
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Quoting Tazmanian:




well said
.
Your family here, people don't like it, they can go elsewhere.
Quoting FLdewey:


It's not a spelling bee, but it would be nice not to have to try and decipher what every post means. BOLD me all you want but I still poke occasional fun at his horrible grammar. I mean really... nose vs nos? comment vs commet. LOL.

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.
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1164. WFOR comes next.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
1174. Grothar
Quoting fatlady99:


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.....


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.
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Good points Bordanaro. It looks like Cape Verde season is about to start early.
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Quoting sailingallover:
Someone must be paying ASCAT and WINDSAT to miss the areas I want to look at.
It's times like this when u really miss QUIKscat.... not that it caught everything, but it usually would catch the whole of something, intead of always catching only a small part...
Member Since: October 25, 2005 Posts: 19 Comments: 21392
There is still a Bahama Blob.

Caribbean - Rainbow Loop

Looks to be headed for Caymans.
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Quoting FLdewey:


Well that's no fun. :-p
LOL! I just don't want him annoying us.
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the commets on this blog are still being re move
Member Since: May 21, 2006 Posts: 5091 Comments: 114696
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1166. TxKeef
Quoting MiamiHurricanes09:
It shouldn't be upgraded to a category 3 because recon clearly did not find category 3 strength winds. The low pressure can be attributed to the large size of Alex (skater effect). And, I do think Alex will be retired. For example, Lili in 2002 caused less money in damage and killed less people but was still retired.


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.
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Quoting ElConando:


WHO normally does not retire storms that primarily affect Haiti. Due to the fact that most of the damage that is done to Haiti could be prevented. As an example deforestation has probably contributed to storms that have killed many people in Haiti from landslides as well as fast moving flood waters such as Gordon from 1994 and Hanna in 2008.
Does Haiti normally request the retirement?
Member Since: October 25, 2005 Posts: 19 Comments: 21392
WARNING! JFV has returned yet again with the username "WSVN". Please ignore and report him immediately when he sign on to avoid any problems.
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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.