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

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

Share this Blog
5
+

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

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 714 - 664

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61Blog Index

OMG will you kids grow up! This is getting ridiculous. Everyone is entitled to their own opinion. Also, there is no one on this blog who is 100% right all the time. I come here to learn what may be happening now and in the near future. Not to see a bunch of kids fighting among themselves stating "I am right and you are wrong"!
Member Since: Posts: Comments:
Quoting CybrTeddy:


Nah, that's a troll watch. Troll warnings is when you has popcorn in one hand and head-on in the other.


LOL
Member Since: Posts: Comments:
Quoting CybrTeddy:


Nah, that's a troll watch. Troll warnings is when you has popcorn in one hand and head-on in the other.
Teddy's correct...
Member Since: Posts: Comments:
http://www.ssd.noaa.gov/eumet/eatl/flash-ir4.html

During the animation, if you click on HDW-high (upper-level wind vectors), easterly winds aloft aligned with low-level easterlies, there is lots of low wind shear in the E Atlantic right now. It'll be interesting to see if both the wave over Africa right now and the wave that entered the Atlantic yesterday show some signs of slow development over the next couple of days.
Member Since: Posts: Comments:
Hadji wasnt too Shabby either tkeith.

And Bandit can do better than sum here.


Woof!!
Member Since: July 3, 2005 Posts: 424 Comments: 128331
Quoting angiest:


Is a troll warning three red squares with black squares inside them?


Nah, that's a troll watch. Troll warnings is when you has popcorn in one hand and head-on in the other.
Member Since: Posts: Comments:
looks like JFV got lock up
Member Since: May 21, 2006 Posts: 5091 Comments: 115122
684. Patrap 4:15 PM CDT on July 12, 2010

Race Banion...he was an excellant forecaster.

Member Since: Posts: Comments:
706. IKE
Quoting reedzone:


Why waste money at the movies when you have the wunderground blog!


LOL...true.

The fickle finger award goes to.....

Member Since: Posts: Comments:
Quoting BaltOCane:


"funny" Haha or "funny" weird?
As in, "haha". LOL.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting MiamiHurricanes09:
Yeah! It's entertaining watching you! Poof!


LMAO.
Member Since: May 21, 2006 Posts: 5091 Comments: 115122
Quoting sirmaelstrom:


That's what I found when I googled for a solution. The problem is that I have no entries in my blog, and it also won't let me Create Blog or Add New Entry. Both just redirect back to the "show.html" page.


I had the same exact problem and noone here was able to help. After unsucessfully adding my own blog, now all my ignore functions work.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
LMAO, it's been a funny afternoon on here.


"funny" Haha or "funny" weird?
Member Since: Posts: Comments:
Member Since: July 3, 2005 Posts: 424 Comments: 128331
Quoting Jeff9641:
You know it's bad when Storm hits the poof button.
LMAO, it's been a funny afternoon on here.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting hurrkat05:
well reed you have to admit it's entertaining...
Yeah! It's entertaining watching you! Poof!
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting StormW:


Better than Rowan and Martin's Laugh In!


LOL
Member Since: Posts: Comments:
Quoting CybrTeddy:
Well, StormTop's obviously out of ideas to kill off the season so he's resorted to insulting bloggers. A typical troll backup plan. The flags are raising on his posts.


Is a troll warning three red squares with black squares inside them?
Member Since: Posts: Comments:
Well, StormTop's obviously out of ideas to kill off the season so he's resorted to insulting bloggers. A typical troll backup plan. The flags are raising on his posts.
Member Since: Posts: Comments:
Looking at the Best Track data, I don't see a stall at 95W. If anything it slowed down at 90W for 6-12 hours.



AL 02 2010070306 159N 760W
AL 02 2010070312 162N 775W
AL 02 2010070318 150N 799W
AL 02 2010070400 154N 808W
AL 02 2010070406 157N 816W
AL 02 2010070412 160N 822W
AL 02 2010070418 164N 826W
AL 02 2010070500 168N 831W
AL 02 2010070506 174N 837W
AL 02 2010070512 180N 845W
AL 02 2010070518 186N 854W
AL 02 2010070600 191N 863W
AL 02 2010070606 196N 873W
AL 02 2010070612 201N 883W
AL 02 2010070618 206N 892W
AL 02 2010070700 211N 901W
AL 02 2010070706 216N 911W
AL 02 2010070712 221N 920W
AL 02 2010070718 228N 929W
AL 02 2010070800 236N 936W
AL 02 2010070806 245N 949W
AL 02 2010070812 257N 964W
AL 02 2010070818 260N 978W
Member Since: Posts: Comments:
For those of you who are talking about african waves eating dry dust, just look at this water vapor image:

http://www.ssd.noaa.gov/eumet/eatl/wv-l.jpg

Whites and blues show moist air, there is moist air in the belt where the tropical waves are, no dry air to me.
Member Since: Posts: Comments:
Quoting StormW:


Oh darn, I just hit the POOF button!
LMAO.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting IKE:
*popcorn ready....salt it and sit back*


Why waste money at the movies when you have the wunderground blog!
Member Since: Posts: Comments:
Quoting hurrkat05:
miami you are a good kid but you need a better attitude..you need to look up the definition of opinion...that's your first assignment
Since everyone is doing I guess I'll join the party!

Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting Patrap:


The Apollo 13 analogy for the 3rd time.

Thats a 15 minute No blogging penalty.

In da box ya go CT.

Hand me yer keyboard.


LOL Pat.
Member Since: Posts: Comments:
Quoting StormW:


Measures the strength and position of the upward motion (or upward vertical velocity) of the MJO.


Thanks Storm! Getting time for me to head out.
Member Since: Posts: Comments:
679. IKE
*popcorn ready....salt it and sit back*
Member Since: Posts: Comments:
hey keep i sent you mail
Member Since: May 21, 2006 Posts: 5091 Comments: 115122
Quoting StormW:


Measures the strength and position of the upward motion (or upward vertical velocity) of the MJO.


thank you!

<--- starting to get it
Member Since: Posts: Comments:
Quoting angiest:


I'm trying to extrapolate from what is interesting to the Atlantic basin to what is interesting to any given basin. :)
Ah, I see.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting MiamiHurricanes09:
Our area is octant 1 and 8, but for development you look for octant 1 and 2.


I'm trying to extrapolate from what is interesting to the Atlantic basin to what is interesting to any given basin. :)
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
I'm sure I will, but not from you.


lol
Member Since: July 6, 2010 Posts: 113 Comments: 32068
Quoting hurrkat05:
miami just sit back and learn...you will learn lots this season..


Member Since: July 6, 2010 Posts: 113 Comments: 32068
Quoting hurrkat05:
miami just sit back and learn...you will learn lots this season..
I'm sure I will, but not from you.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting sirmaelstrom:


Yeah. Mine works now after refreshing about twenty times. I went ahead and created a test blog just in case too. Hopefully it's fixed. Thanks to both StormGoddess and angiest for replying.

Oh wow, maybe that's the way to get it to work then! Glad you got it working, yay! Well everybody you guys have a great day and I just hope that no one gets hurt anymore this season more than has already happened from storms and everyone's houses are safe. Check back later. Have a good one. :)
Member Since: Posts: Comments:
StormW, what does that graph measure anything (heat content, pressure, etc) or is it just "measuring" the potential, due to all these ingrediants?
Member Since: Posts: Comments:
Quoting angiest:


So for conditions to be (conducive to? better for? able to enhance?) TC development, you would "want" the MJO to be east of where your basin actually develops its storms?
Our area is octant 1 and 8, but for development you look for octant 1 and 2.
Member Since: September 2, 2009 Posts: 130 Comments: 21193

Viewing: 714 - 664

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61Blog Index

Top of Page

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.