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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2314. Dakster
Quoting MiamiHurricanes09:
Typhoon Tip, if it were making landfall along the eastern U.S coastline affects will be felt from Miami to New York. Something like this will likely never be seen in the Atlantic unless we have the monsoonal type development by the Cape Verde's, similar to Alex in the Caribbean.



Thanks for cursing us...

If we get a Typhoon Tip in the Atlantic this year...
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2313. Dakster
Quoting MiamiHurricanes09:
That's why we don't use the NAM for determining cyclogenesis.


and the CMC - although it has gotten better.
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2312. xcool
joe b so mad lolol
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting MiamiHurricanes09:
Look back through the posts to around last night's comments. We explained the influences things such as the La Ni�a, NAO, AO, etc... have on the upcoming winter.
I just did some research on climate prediction page..and from what I read la Nina tends to produce dry n mild winters.. I know this past winter down this way was wet n cold when El Nino was present,,we even had snow here in panhandle!!!
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Quoting StormW:


Yes,
The NAM model tries to spin up something from the weather that's near the Bahamas

That's why we don't use the NAM for determining cyclogenesis.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Typhoon Tip, if it were making landfall along the eastern U.S coastline affects will be felt from Miami to New York. Something like this will likely never be seen in the Atlantic unless we have the monsoonal type development by the Cape Verde's, similar to Alex in the Caribbean.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
G'Nite all...cigar calling and she says "enough" with my blogitude. Patrick, still love the Department of the Navy symbol avatar, miss Ironman II, asume he's rusty and needed a shine...
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2303. hydrus
I want to be a colored circle-caster. I will predict where, when and what color the suspected area will be.
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Link
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I see the Big Enormous Wave continues to come off the coast of Africa.


Into the Great Wide Open
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Quoting stormhank:
Not trying to fast forward to winter or anything,,but does anyone know since were goin into the La Nina phase how LaNina's affect the winter?? warm n dry or cold n wet etc???
Look back through the posts to around last night's comments. We explained the influences things such as the La Nia, NAO, AO, etc... have on the upcoming winter.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
The Sat24 really shows the potential of the CV system.
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2297. Ossqss
Lets hope we don't see an

Alabaster Master Disaster Aristo-caster :)
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Quoting stormhank:
Not trying to fast forward to winter or anything,,but does anyone know since were goin into the La Nina phase how LaNina's affect the winter?? warm n dry or cold n wet etc???

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Quoting StormW:


Not ignoring you, looking at some updated stuff.


Was that meant for me?
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Not trying to fast forward to winter or anything,,but does anyone know since were goin into the La Nina phase how LaNina's affect the winter?? warm n dry or cold n wet etc???
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Quoting F4PHANTOM:
Which station?


Channel 2, kprc.
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Quoting Dakster:


It was the CMC, but it dropped in on subsequent runs. Not sure what the latest run will show.


Thanks Dakster!
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Weather getting worse...Sig doesn't like what he sees
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Quoting fldude99:
My prediction is nothing in the GOM in 2010...all these so called experts are off the mark


All of our systems have gotten into the Gulf so far including a near-Major Hurricane.
Member Since: July 8, 2005 Posts: 259 Comments: 24512
Storm, admit it, you were whistlin after reading my slow casters line ;)
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2288. xcool
huh 39 stoms
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting fldude99:
My prediction is nothing in the GOM in 2010...all these so called experts are off the mark


huh? we already had Alex...
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Quoting StormW:


Ahhh...a Mark caster


I believe the word your looking for is maroon :)
The colour of course :)
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Quoting CybrTeddy:


39 named, 26 hurricanes, 7 Category 5s. This blog would collapse if that was the Atlantic.


If we had 39 named in the atlantic, it will go up to TS/Hurricane Sigma (18th greek letter)!
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You posted the Eumetsat satellite.
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2282. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #17
SEVERE TROPICAL STORM CONSON (T1002)
9:00 AM JST July 14 2010
============================

SUBJECT: Category Two Typhoon In The South China Sea

At 0:00 AM UTC, Severe Tropical Storm Conson (990 hPa) located at 14.8N 119.8E has 10 minute sustained winds of 50 knots with gusts of 70 knots. The cyclone is reported as moving west at 14 knots.

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

Forecast and Intensity
========================
24 HRS: 17.2N 116.2E - 55 knots (CAT 2/Severe Tropical Storm)
48 HRS: 19.3N 112.8E - 70 knots (CAT 3/Strong Typhoon)
72 HRS: 21.1N 110.0E - 55 knots (CAT 2/Severe Tropical Storm)
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well storm one thing i can predict lol tampa will finish last in the nfc south in 2010 bad coach caster.
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Final episode for Capt Phil now showing on Discovery for the Deadliest Catch(DCT)...weather looks OK so far
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Mostly created this for the Amateurs on my Webiste to read but take a look if interested...

Why the wind blows?
Link
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2278. xcool
hmmm
Member Since: September 26, 2009 Posts: 2 Comments: 15684
My prediction is nothing in the GOM in 2010...all these so called experts are off the mark
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Quoting MiamiHurricanes09:
1964 was the most active Western Pacific typhoon season, it consisted of 39 named storms, 26 typhoons, and 7 super typhoons.


39 named, 26 hurricanes, 7 Category 5s. This blog would collapse if that was the Atlantic.
Member Since: July 8, 2005 Posts: 259 Comments: 24512
StormW: There's a link to the SAL on the main page of tropical weather. It's from the University of Wisconsin. One page back from this one. It has a five day movie of the SAL progress and/or regress. That's why you're noticing the development tonight.
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2271. Dakster
Quoting PtownBryan:
Hey everyone. Hope all is well. I had a question. Tonight on the local news here in Houston, they showed a model that brought something tropical from the Caribbean into the gulf towards Texas for this coming weekend. Does anyone have any knowledge of that? The model had it spinning as if it were a tropical storm. Thanks!


It was the CMC, but it dropped in on subsequent runs. Not sure what the latest run will show.
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Hey everyone. Hope all is well. I had a question. Tonight on the local news here in Houston, they showed a model that brought something tropical from the Caribbean into the gulf towards Texas for this coming weekend. Does anyone have any knowledge of that? The model had it spinning as if it were a tropical storm. Thanks!
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No wonder the NFL and the President partenered up for the nfl's play 60. They must have seen all the teens sitting on a computer on this blog when thier is zilch out there.Maybe a lot of adults on here should consider the play 60 lol.Just a little humour folks lol.
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AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
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2267. xcool
Atlantic and Caribbean Tropical Satellite Imagery

work for me
Member Since: September 26, 2009 Posts: 2 Comments: 15684
2266. Grothar
Look at Central Africa, copious amounts of precipitation!

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Quoting Grothar:
Hey, MiamiHurricane09; :P

ROFL!
Member Since: September 2, 2009 Posts: 130 Comments: 21194

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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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