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 StormW:


For development here in our basins, you want the MJO in octants 1 & 2


What I'm getting at is if the MJO is in octants 7 or 8, does that increase development of WPAC storms?
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Quoting TropicalAnalystwx13:


You are a very rude and mean person. You really need to learn to respect people, and a lot of other things. Instead of spending your day torturing us, why dont you go and learn that?


Scottsvb will give him kudos for that one. Again, I will say this, I never predicted a landfall east of Texas.
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Quoting CybrTeddy:


Not even the NHC forecasted Alex to stall like it did. Mother nature is hers alone and cannot be judged by one single person. Currently, there are a 1000 steps that have to be followed in order before the end of Hurricane season and we are on number 8, your off talking about number 692.


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.
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Quoting hurrkat05:
yes i think it matters ta because no one in here including storm w and the nhc did...and reed did say once he saw it stalled for everyone from northern mexico to mobile alabama to watch for this...i even laughed when i read his post...


You are a very rude and mean person. You really need to learn to respect people, and a lot of other things. Instead of spending your day torturing us, why dont you go and learn that?
Member Since: July 6, 2010 Posts: 113 Comments: 33876
Quoting hurrkat05:
reed i ask you one more time did you forecast the stall at 95w like i did on alex...you are avoiding the question guy


Not even the NHC forecasted Alex to stall like it did. Mother nature is hers alone and cannot be judged by one single person. Currently, there are a 1000 steps that have to be followed in order before the end of Hurricane season and we are on number 8, your off talking about number 692.
Member Since: July 8, 2005 Posts: 259 Comments: 24869
Quoting hurrkat05:
yes i think it matters ta because no one in here including storm w and the nhc did...and reed did say once he saw it stalled for everyone from northern mexico to mobile alabama to watch for this...i even laughed when i read his post...
I'm laughing right now reading your posts!
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting StormW:


The chart is broken up into 8 Octants, which correspond to different ocean areas.



8 and 1 cover the western hemisphere (our area) and the index progresses from left to right (counterclockwise to the east). Over in Octant 2 is closer to Africa. Once past 2, you get to the Indian ocean and so on.

I believe the Maritime Continent refers to the areas of Asia, then we get to the WPAC.

The farther from the center of the chart, the stronger the MJO phase.

We usually see development in the Caribbean, or Atlantic when the index is in Octants 1 and 2. This has been proven last season and this season so far.


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?
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Quoting StormW:


img src="" alt="" />


lol storm...
Member Since: July 6, 2010 Posts: 113 Comments: 33876
thanks pat
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Quoting CybrTeddy:


Again and I'm sure this will be ignored by most of the people predicting a slower season, the numbers in July don't matter at all. 1969 had 18 named storms, only 1 in July. 2007 had 15 named storms, 7 in September.
Yep Correct and if you remember 2004 started out slow and look what it produced Some really nasty ones Frances and Jeanne hit within a mile or two of each other three weeks apart. You're right Teddy with the indicators there We'll have to wait and see, But with the SST's and ACE index doesn't look to good for a mild Season
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Quoting angiest:


What format is the video? Firefox on linux can't find a plugin for me and I am not seeing anything indicating what type of video it is.


Its a ROV live Feed from here

BP Live feeds from remotely operated vehicles (ROV)

ROV footage - live stream
Live video links from the ROVs monitoring the damaged riser.
Please be aware, these are live streams and may freeze or be unavailable from time to time.
Live feeds from Ocean Intervention III

ROV 1
ROV 2
Live feeds from Viking Poseidon
ROV 1
ROV 2
Live feeds from Boa Deep C
ROV 1
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Live feeds from Skandi
ROV 1
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Live feeds from Enterprise
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Live feeds from Q4000
ROV 1
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Quoting hurrkat05:
reed i ask you one more time did you forecast the stall at 95w like i did on alex...you are avoiding the question guy


It doesn't really matter now does it?
Member Since: July 6, 2010 Posts: 113 Comments: 33876
Quoting StormW:


The chart is broken up into 8 Octants, which correspond to different ocean areas.



8 and 1 cover the western hemisphere (our area) and the index progresses from left to right (counterclockwise to the east). Over in Octant 2 is closer to Africa. Once past 2, you get to the Indian ocean and so on.

I believe the Maritime Continent refers to the areas of Asia, then we get to the WPAC.

The farther from the center of the chart, the stronger the MJO phase.

We usually see development in the Caribbean, or Atlantic when the index is in Octants 1 and 2. This has been proven last season and this season so far.
Thanks!
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting BDAwx:

Thank you! :D


Your welcome, you showed evidence backing up your statements, very well done.
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Quoting KEEPEROFTHEGATE:
OILCANO

Link


What format is the video? Firefox on linux can't find a plugin for me and I am not seeing anything indicating what type of video it is.
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Quoting TropicalAnalystwx13:


Good Job!


I didn't keep it though, but never had it going to LA or northern Texas. One can argue that I did, but he never posted evidence of me saying it was heading to LA/TX borderline, he is actually a MET believe it or not. I always kept my red line around Northern Mexico and Southern Texas, while I had the outer cone just touching the borderline of LA/TX. This, he failed at proving that I wishcasted the storm to hit LA, thought because he is a MET, people believed him and ignored me. Though, in the end, I moved on.
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Quoting StSimonsIslandGAGuy:
I saw this in Dr. Master's blog

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.


I wonder about the error band of a forecast like this. I mean really, a 70% chance of between 13 and 27 storms doesn't sound much more useful than saying "we forecast an above average season"


It is a requirement to participate in the WMO Tropical Cyclone Seasonal Forecast program.

"Another requirement for inclusion on the WMO website is that the forecast group must
provide a measure of uncertainty for any seasonal tropical cyclone forecast variable."

Link
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OILCANO

Link
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Thunderstorm complex approaching just strengthened from 40 mph to 60 mph in 10 minutes!

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR... BIBB COUNTY IN CENTRAL GEORGIA SOUTHERN JONES COUNTY IN CENTRAL GEORGIA SOUTHEASTERN MONROE COUNTY IN CENTRAL GEORGIA

* UNTIL 530 PM EDT

* AT 451 PM EDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS UP TO 60 MPH. THIS STORM WAS LOCATED 9 MILES WEST OF PAYNE CITY... MOVING EAST AT 30 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MACON AND LAKE TOBESOFKEE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU SEE WIND DAMAGE... LARGE HAIL OR SIGNIFICANT FLOODING... WAIT UNTIL THE STORM HAS PASSED... AND THEN CALL THE NATIONAL WEATHER SERVICE TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

It's nearly pitch black outside.
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Member Since: July 1, 2005 Posts: 10 Comments: 1683
Quoting hurrkat05:
ok teddy im saying around the 10th of august as it stands right now definitely nothing in july...


Conditions are not unfavorable for development, I dont know why you dont listen to us. The SAL off Africa is not affecting any of the waves badly at the moment, and if you would stop by StormW's blog, it can take moisture from the south if it needed to to help survive. There is a really good chance of at least 1 named storm by the end of july, with 2, or even 3 possible. Listen to Drak, Levi, Storm, and others, maybe you'll learn something. ;)
Member Since: July 6, 2010 Posts: 113 Comments: 33876
Quoting reedzone:
Not to say who was right or wrong with Hurricane Alex, but this was my forecast before it hit the Yucatan based on the steering and pattern.

Photobucket


Certainly looks like you nailed it.
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Wave over Western Africa will likely be eating dust though

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do i spay a pine hole eye
Member Since: May 21, 2006 Posts: 5093 Comments: 115810
628. BDAwx
Quoting reedzone:


Best post of the day! Kudos.. :)

Thank you! :D
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Quoting reedzone:
Not to say who was right or wrong with Hurricane Alex, but this was my forecast before it hit the Yucatan based on the steering and pattern.

Photobucket


Good Job!
Member Since: July 6, 2010 Posts: 113 Comments: 33876
Im gonna take a nappy.

Current Conditions

Mid City Station, New Orleans, Louisiana (PWS)
Updated: 1 sec ago

Scattered Clouds


98.5 °F


Scattered Clouds
Humidity: 51%
Dew Point: 77 °F
Wind: 2.0 mph from the West
Wind Gust: 4.0 mph
Pressure: 29.89 in (Falling)

Heat Index: 115 °F

Visibility: 10.0 miles
UV: 9 out of 16
Pollen: 3.50 out of 12
Pollen Forecast new!
Clouds:
Scattered Clouds 4200 ft
Scattered Clouds 5500 ft
(Above Ground Level)
Elevation: 25 ft
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Quoting StSimonsIslandGAGuy:
Drakoen it looks like it's trying to form a 400 mile wide eye over land ;)

But its not a pinhole eye!!
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Quoting hurrkat05:
ok teddy i willll be looking for that..so you saying something will form before the end of the month am i right


Nothing is ever 'Will' unless its Will Smith. I do believe we will see atleast 1 storm before July 31st.
Member Since: July 8, 2005 Posts: 259 Comments: 24869
Quoting MississippiWx:


2010 still a good bit warmer in the MDR and GOM (where Alex's wake isn't) than 2005. As soon as the A/B high weakens in about a week or so, it's game time.
The NAO is already on a downturn. Expect the pressure within the B/A high to slowly erode as the NAO turns neutral and then consequently negative.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting StSimonsIslandGAGuy:
I saw this in Dr. Master's blog

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.


I wonder about the error band of a forecast like this. I mean really, a 70% chance of between 13 and 27 storms doesn't sound much more useful than saying "we forecast an above average season"
70% chance of between 13 and 27 is expressing the science of statistics without applying the art of forecasting on top of it (typed with a nod to Senior Chief who often speaks to the difference between the art and science of being a forecaster)...
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620. xcool


look like small rotation at 55 w

hmmm hmm ?
Member Since: September 26, 2009 Posts: 2 Comments: 15705
Not to say who was right or wrong with Hurricane Alex, but this was my forecast before it hit the Yucatan based on the steering and pattern.

Photobucket
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2010 still a good bit warmer in the MDR and GOM (where Alex's wake isn't) than 2005. As soon as the A/B high weakens in about a week or so, it's game time.
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Quoting TropicalAnalystwx13:


weeks?


Like 1-2 weeks, yea and as the MJO wave comes in, we'll see enhanced amounts of moisture so that will help kill off the SAL.
Member Since: July 8, 2005 Posts: 259 Comments: 24869

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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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