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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1362. xcool
buzz
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Quoting CaneAddict:


Your gonna be saying it's too busy in the Atlantic in about a week or so...Everything favors a huge ramp up in activity.


To be honest, I prefer real activity than nothing at all. I'm not wanting anything to hit land, but I just want something to track.
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Quoting jlp09550:
Howdy everyone! It's too quiet in the Atlantic..


Your gonna be saying it's too busy in the Atlantic in about a week or so...Everything favors a huge ramp up in activity.
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1359. JLPR2
Quoting Hurricanejer95:
We are in La Nina now, a weak-moderate La Nina
Link
20100517,20100523,-0.23
20100524,20100530,-0.06
20100531,20100606,-0.19
20100607,20100613,-0.31
20100614,20100620,-0.42
20100621,20100627,-0.41
20100628,20100704,-0.48
20100705,20100711,-0.73



that was quite a plunge O_O
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We are in La Nina now, a weak-moderate La Nina
Link
20100517,20100523,-0.23
20100524,20100530,-0.06
20100531,20100606,-0.19
20100607,20100613,-0.31
20100614,20100620,-0.42
20100621,20100627,-0.41
20100628,20100704,-0.48
20100705,20100711,-0.73
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Quoting 7544:
gem shows 2 system for so fla hmmmm is it right ?

Link



that mode run is more likey being a wishcater
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Quoting Bordonaro:
Twas the night before July 13TH and all through the house, not an Atlantic Tropical disturbance was stirring, no, not even a mouse (like 95L).

The Hurricane tracking charts were hung by the chimney with care, hoping the Cape Verde season soon would be here.

The WU bloggers were all snug in their bed, with visions of Hurricanes dancing through their heads.

And mamma in her kerchief, and I in my cap.
Had just settled our brains for brief summers nap.

When out on the Satellite there arose such a clatter. I sprang to the computer screen to see what was the matter. Out of the bed I flew like a flash, tore open the laptop, threw open the cache.

The moon on the breast of the new-fallen blog.
Gave the lustre of mid-day to objects from the fog. When, what to my wondering eyes should appear, but a new TC and eight tiny Invests..




:)
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1354. xcool
lol
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1352. PasBon
Gosh, I hope we don't end up having 4.4 major storms!

I can deal with 4, but not 4.4. WAYYY too many. :)
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Twas the night before July 13TH and all through the house, not an Atlantic Tropical disturbance was stirring, no, not even a mouse (like 95L).

The Hurricane tracking charts were hung by the chimney with care, hoping the Cape Verde season soon would be here.

The WU bloggers were all snug in their bed, with visions of Hurricanes dancing through their heads.

And mamma in her kerchief, and I in my cap.
Had just settled our brains for brief summers nap.

When out on the Satellite there arose such a clatter. I sprang to the computer screen to see what was the matter. Out of the bed I flew like a flash, tore open the laptop, threw open the cache.

The moon on the breast of the new-fallen blog.
Gave the lustre of mid-day to objects from the fog. When, what to my wondering eyes should appear, but a new TC and eight tiny Invests..


Member Since: August 25, 2009 Posts: 20 Comments: 6785
Howdy everyone! It's too quiet in the Atlantic..
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Quoting TexasHurricane:
Hi everyone, is this area by Florida a potential for development?



Not really
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Quoting Tazmanian:



nop and nop


ok....
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Quoting TexasHurricane:
Hi everyone, is this area by Florida a potential for development?




nop and nop
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tuesday will be the big 50K day
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Hi everyone, is this area by Florida a potential for development?

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Quoting Orcasystems:


That would be a good supposition from the available data, I would have to confirm the model data. I am a canuck, so of course I will go with the CMC or CMC2 track :)



ok
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Comments:

I should take the advice from a wise man.

Its better to have someone believe you are a fool.... then to open your mouth and prove it :)

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3425 comments and 41 entries posted by all members in the last 24 hours.

You have posted 10 entries in your own blog.

You have posted 536 comments in all blogs.

I need to get commenting this all since 2005

lol
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Quoting Tazmanian:



in other words you have posted 15,158 commets


That would be a good supposition from the available data, I would have to confirm the model data. I am a canuck, so of course I will go with the CMC or CMC2 track :)
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Quoting Orcasystems:
Ok, I talk to much... I think most of it is Jokes in my own blog.

You have posted 15158 comments in all blogs.



in other words you have posted 15,158 commets
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Quoting GeoffreyWPB:


WBZT 1230-AM
GOAL!!!!! That's good news. tks Good night all.
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Quoting Orcasystems:
Ok, I talk to much... I think most of it is Jokes in my own blog.

You have posted 15158 comments in all blogs.

I have only posted about 1/3 that. However, I have only been a member for 11 months :o)!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting CosmicEvents:
Phil Hendrie is on down here! I like him. What station?


WBZT 1230-AM
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Ok, I talk to much... I think most of it is Jokes in my own blog.

You have posted 15158 comments in all blogs.
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Not a big Bogart fan...Although that is my nickname because of my impersonation of him...However, I did like Key Largo.
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Quoting GeoffreyWPB:
Almost time for Phil Hendrie. Hope Bobbie Dooley is on this morning.
Phil Hendrie is on down here! I like him. What station?
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here you go


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3413 comments and 41 entries posted by all members in the last 24 hours.

You have posted 5075 entries in your own blog.

You have posted 48009 comments in all blogs.
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Almost time for Phil Hendrie. Hope Bobbie Dooley is on this morning.
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This is very interesting for week 2



Text note says

There is a slight chance for tropical development in the tropical North Atlantic. Large scale conditions(SSTs, wind shear, and tropical waves from Africa) are forecasted to be favorable during the later portions of this period but the threat is considered low at the current time.
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Quoting Tazmanian:
this a little update


3614 comments and 40 entries posted by all members in the last 24 hours.

You have posted 5075 entries in your own blog.

You have posted 48000 comments in all blogs.

Taz, where do you find this info?
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Tazmanian:
yup thats for sure you can call me the talking taz


Where do you find that anyway?
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1325. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #10
SEVERE TROPICAL STORM CONSON (T1002)
12:00 PM JST July 13 2010
============================

SUBJECT: Category Two Typhoon In Seas East Of The Philippines

At 3:00 AM UTC, Severe Tropical Storm Conson (975 hPa) located at 14.3N 124.2E has 10 minute sustained winds of 60 knots with gusts of 85 knots. The cyclone is reported as moving west at 14 knots.

Storm Force Winds
=================
60 NM from the center

Gale Force Winds
=================
150 NM from the center

Forecast and Intensity
========================
24 HRS: 15.7N 119.7E - 70 knots (CAT 3/Strong Typhoon)
45 HRS: 17.3N 117.2E - 75 knots (CAT 3/Strong Typhoon)
69 HRS: 19.3N 113.9E - 80 knots (CAT 3/Strong Typhoon)
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1324. HadesGodWyvern (Mod)
Philippines Atmospheric Geophysical Astronomical Service and Administration
TYPHOON "BASYANG" (CONSON)
Tropical Cyclone Bulletin #6
==============================================

"BASYANG" has intensified into a Typhoon as it moves towards Aurora-Northern Quezon Area.

At 10:00 AM PhST, Typhoon Basyang (Conson) located at 14.3°N 124.4°E or 90 km north of Virac, Catanduanes has 10 minute sustained winds of 65 knots with gusts of 80 knots. The cyclone is reported as moving west at 11 knots.

Signal Warnings #3
===================

Luzon Region
------------
1.Catanduanes
2.Camarines Norte
3.Northern Quezon
4.Polillo Island
5.Aurora

Signal Warnings #2
=======================

Luzon Region
------------
1.Camarines Sur
2.Southern Quezon
3.Laguna
4.Rizal
5.Bulacan
6.Nueva Ecija
7.Nueva Vizcaya
8.Quirino
9.Ifugao
10.Isabela

Signal Warnings #1
=======================

Luzon Region
------------
1.Metro Manila
2.Albay
3.Marinduque
4.Batangas
5.Cavite
6.Bataan
7.Pampanga
8.Zambales
9.Tarlac
10.Pangasinan
11.La Union
12.Benguet
13.Mt. Province
14.Ilocos Sur
15.Kalinga
16.Apayao
17.Abra
18.Cagayan Ifugao
19.Abra

Additional Information
========================
Residents living in low lying and near mountain slopes under signals # 3,2 and 1 are advised to take all the necessary precautionary measures against flashfloods and landslides.

Those living along the coast in areas under signal # 2 and 3 are advised to be on alert against big waves generated by the typhoon.

The public and the disaster coordinating councils concerned are advised to take appropriate actions and watch for the next bulletin to be issued at 5 PM today.
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1323. 7544
gem shows 2 system for so fla hmmmm is it right ?

Link
Member Since: May 6, 2007 Posts: 0 Comments: 6690
yup thats for sure you can call me the talking taz
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Quoting Tazmanian:
this a little update


3614 comments and 40 entries posted by all members in the last 24 hours.

You have posted 5075 entries in your own blog.

You have posted 48000 comments in all blogs.


Decoded.... you talk a lot :)
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AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
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this a little update


3614 comments and 40 entries posted by all members in the last 24 hours.

You have posted 5075 entries in your own blog.

You have posted 48000 comments in all blogs.
Member Since: Posts: Comments:
1318. xcool
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Link
The scene
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1315. 47n91w
Quoting Baltimorebirds:
I don't think theirs a walmart in africa.LoL.


Southern Africa has 'Game' stores, which reminded me a bit of Shopko.

Instead of Wal-mart, how 'bout... got Game??


Edited: I just found the Game website. Their motto is "you always WIN"
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1314. Grothar
Quoting Grothar:


Cantinflas?? What is wrong with you Geoff. It is one of the greatest lines from "Treasure of the Sierra Madres" you must be slipping. LOL


His name was Alfonso Bedoya!
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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.

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