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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Quoting all4hurricanes:
Poll: Who think Alex will
:Be Upgraded to a Category three in post season considering it's pressure at 947
: Retire considering it caused over a billion dollars in damage

sorry accidently hit quote
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Quoting all4hurricanes:
Poll: Who think Alex will
:Be Upgraded to a Category three in post season considering it's pressure at 1947
: Retire considering it caused over a billion dollars in damage
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.
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agree fat lady wish they still had movies like that.
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1060. help4u
Night everyone,stay safe.No killing tonight.
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Quoting Bordonaro:
Oh, please tropical Atlantic, please, we need at least 1 or 2 Invest's to track, so the bickering will stop!!


I second that.

Quoting all4hurricanes:
Poll: Who think Alex will
:Be Upgraded to a Category three in post season considering it's pressure at 1947
: Retire considering it caused over a billion dollars in damage


1. Possibly.

2. Doubtful.
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i did not start the obermann mess cffin just my opinion.For many years in the past this blog had no problem bashing bush or any conservative.Now the shoe gets put on the other foot and paople complain double standard?
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Quoting Chicklit:


Hang 'em High is an old Clint Eastwood movie.
Called "spaghetti western' genre. Is that before your time?
Clint went around the wild west, rounded up the bad guys, and got rid of them because they were hurting a lot of good, honest, hard working people, not their wives.


Great movie reference!

One of my favorite quotes that might work here is Clint's Dirty Harry line, "Ya know, opinions are like a$$h0lz. Everybody has one."

or

"Ya got kids? No? Lucky them."

LOL!!!
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Quoting Chicklit:


Well, if I didn't get that exactly right, I'm sorry. I went to those movies (drive in) with my boy-friend-at-the-time who liked them. This is what I got from it. Clint was the good guy, rounding up the bad guys, and making the world safer for everyone who works hard and just wants to be happy to live in.


I think you meant High Plains Drifter, my friend.
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Poll: Who think Alex will
:Be Upgraded to a Category three in post season considering it's pressure at 947
: Retire considering it caused over a billion dollars in damage
Member Since: Posts: Comments:
Oh, please tropical Atlantic, please, we need at least 1 or 2 Invest's to track, so the bickering will stop!!
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Quoting Baybuddy:

Chicktwit...Hang em' High was a movie about lynch mobs in the west. Go rent it you twit.


Well, if I didn't get that exactly right, I'm sorry. I went to those movies (drive in) with my boy-friend-at-the-time who liked them. This is what I got from it. Clint was the good guy, rounding up the bad guys, and making the world safer for everyone who works hard and just wants to be happy to live in it. You know, make a living without a lot of weird stuff going on. That's it. And this spill has taken that away from a lot of people.
Member Since: July 11, 2006 Posts: 14 Comments: 11390
baybuddy that was not a nice way to talk to a lady now was it.And most folks i know from Mobile are nicer than that.
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1051. help4u
No not before my time.Bp bad guys and your saying hang them.WOW!!
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Quoting gator23:

the comment about Rush Limbaugh and Keith Olberman had zero to do with the oil spill.


Agreed. The oil spill and the effects of tropical weather on it are important topics, but this is not the venue for cheerleading for Rush or any other political TV talking heads. Admin seems to be pretty serious about it.
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1048. beell
Quoting bappit:

From my 1962 copy (eleventh printing) of the Golden Nature Guide to Weather:

Machine forecasting as accurate as human forecasting, or more so, is now being done by electronic computers. The U.S. Joint Numberical Weather Prediction Unit began opeation of the first "electronic brain" for routine weather forecasting in 1955.

They might have been a little cheery in their assessment for the time. Odd that they don't mention goat bones.


Who could forget the "Golden Nature" series?!! I did make a quick check for pre-model forecasting guides. Zippo on the goat bones.

Bats Of The World
Gary Graham
1994

Butterflies And Moths
Robert Mitchell, & Herbert Zim
1962

Herbs And Spices
Julia Morton
1976

Pond Life
George Reid
1967

Hallucinogenic Plants
Richard Schultes
1976

Reptiles and Amphibians
Herbert Zim & Hobart Smith
1953

Spiders & Their Kin
Herbert & Lorna Levi
1968
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one of my favorites chick but not as good as the outlaw josey wales lol
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Quoting weathergeek5:
This is a good vid!!!



Thank u for the video appreciate it watched it all great stuff.
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I was always told by the older folks that i had the opertunity to work with was that the main problem with the oil feild was engineer's
and o-rings combine them and when thing's go wrong it get's bad never really belived it till I saw it with my own eye's the last few month's.
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1033... Damn straight.
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Quoting help4u:
post Chicklit 1012 when you say hang em high,are you calling for violence.A oil exec had a bomb sent to his house today and it blew up in his wife's face.She is lucky to be alive.That quote is sick!!


Hang 'em High is an old Clint Eastwood movie.
Called "spaghetti western' genre. Is that before your time?
Clint went around the wild west, rounded up the bad guys, and got rid of them because they were hurting a lot of good, honest, hard working people, not their wives. That is creepy, cowardly weirdo crap...Clint would never do anything remotely like that.
Member Since: July 11, 2006 Posts: 14 Comments: 11390
thanks earth good to see you and for gator non weather whooodat rollllll tide
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Quoting help4u:
post Chicklit 1012 when you say hang em high,are you calling for violence.A oil exec had a bomb sent to his house today and it blew up in his wife's face.She is lucky to be alive.That quote is sick!!

They (BP) need to be held accountable for their gross negligence.

I am very sorry to hear about the bomb sent to the BP executives home. They need to be punished.
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would you been as mad gator if they had insulted a conservative just curious.
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Quoting StormW:


This is the model I have, the Midland WR-100 works great, easy to understand.

Good place to look is ebay.

WR-100


Just the answer I was looking for, Storm. Thank you, sir!
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1033. help4u
post Chicklit 1012 when you say hang em high,are you calling for violence.A oil exec had a bomb sent to his house today and it blew up in his wife's face.She is lucky to be alive.That quote is sick!!
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1032. Talleck
So I had a question. I was reading about how the Sahara desert is spreading and Africa is in a process of desertification. I also know that dust can diminish a tropical waves chances of developing into a hurricane, I was wondering if anyone is studying the affects of desetification on tropical storm development? I'd be interested in seeing their findings
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1031. gator23
.
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Quoting gator23:

reported. weatherblog


Why? its about the oil spill
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Quoting Baltimorebirds:
Fatlady99 when I've asked a question some people have ignored me and insted responded to more dumdber questions,like focusing their attention on "that man".I had to get used to it.so what I do is ask people directly.


Good suggestion, thanks. I think sometimes folks assume that 'someone else' will answer. ;)
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gator reported ignore. thier is a lot of people interested in this topic because weather is climate and the oil affects the climate.As ike would say another to the list poof.
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Quoting blsealevel:


I'm pretty sure Lowe's, Home Depot, even Wal-Mart and K-Mart and most of your drug stores supply E-Radios that do a good job.
Lowes has been selling some around here they seem to do a good job when the weather gets bad I think it's one you hand crank don't know how long the charge last's though I have a battery operated one w/ tv that works find just need to stock up on the battery's.


Thank you! I'll look into that.
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Quoting Chicklit:
So the folks in Louisiana have been failed by both a Republican and Democrat president.


So what does that tell you? So what of the folly of man?
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gator heres something to ease your uptightness rollllll tideeeeeee.
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1024. gator23
Quoting SAINTHURRIFAN:
oberman is the liberal version of rush limbaugh no objectity at all, no wonder orielly's ratings toast him every night.

reported. weatherblog
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So the folks in Louisiana have been failed by both a Republican and Democrat president.
Member Since: July 11, 2006 Posts: 14 Comments: 11390
1021. gator23
Quoting mcluvincane:


Hard to believe anyone even watches that liberal show. Wow

reported. weather blog
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Quoting SAINTHURRIFAN:
Coast guard omly follows orders just like any branch of the military.They take thier orders from the president the buck stops with him.

Leadership was lacking here for sure.
Member Since: July 11, 2006 Posts: 14 Comments: 11390
Quoting SavannahStorm:


Yikes, don't let the Chief read that!


Failure of command and control from the top...
Nothing more, nothing less.

And dont read into that, i dont care who was in charge, this was eighty four days of five blind men trying to describe an elephant by touch.
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Quoting bappit:
I'm hearing that the Coast Guard passes the buck.

Edit: I don't think that is true. The Coast Guard has a reputation for integrity.


Smooth move, editing that as fast as you did...
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Coast guard omly follows orders just like any branch of the military.They take thier orders from the president the buck stops with him.
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1015. gator23
Quoting Baltimorebirds:
For some odd reason the weather channel continues to try to hype this season to be like another 05.Look at their front page.Go here:Link

maybe not 05 but still VERY active. I mean its onlyh June and we had a strong Cat 2
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1014. Dakster
Quoting TropicalAnalystwx13:


Its a smile :D


Ask KOTG - He seems to have all the smileys around here... But it does look like a sadistic wal-mart smiley.
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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.