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: 264 - 214

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

If enuff flag him he will be gone soon
Member Since: Posts: Comments:
Quoting Jeff9641:


how does he get back on. Once your banned that should be it. I mean they have to know it's him.


All you need to do is use a dif e_mail address
Member Since: Posts: Comments:
259. JLPR2
Quoting btwntx08:

yup i translated it to see what it was and it was really nasty


I dont get it, *scratches head*, does he realize that insult could be used against him too? XD
Member Since: September 4, 2007 Posts: 7 Comments: 8747
221. Reported.
Member Since: Posts: Comments:
255. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
252. JLPR2
Quoting JRRP:

???????????????????????????????????????????????????????


yeah, but dont quote it!
Member Since: September 4, 2007 Posts: 7 Comments: 8747
250. JRRP
Quoting CBS4:


.


???????????????????????????????????????????????????????
Member Since: Posts: Comments:
Quoting CBS4:


Have they've finally recognized it, Teddy?


Yep.
Member Since: Posts: Comments:
246. 7544
97l coming soon stay tuned
Member Since: Posts: Comments:
245. JLPR2
Quoting futuremet:
221. Reported to the admin. It is pointless to say foul words in a foreign language. You can translate anything on Google.


I didn't need to translate it on google, I understand it perfectly, so my finger reported. :P

Hey everyone! :D
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Watching the new spin BP is trying to put on their DH Disaster would be almost funny if it weren't so tragic. The company is following corporate SOP, I suppose: Step 1) Try to convince everyone that there is no oil spill. Step 2) When it becomes obvious to all that there is an oil leak, try to convince everyone that, yeah, sure, oil is leaking, but it's only a little bit. Step 3) When it becomes obvious to all that it's more than "a little bit", try to convince everyone that it's still not as much as they say it is. Step 4) When it becomes obvious to all that there really is a heck of a lot of oil gushing unimpeded into the gulf, try to convince everyone that, okay, yes, there is a lot of hemorrhaging oil, but, given the overall size of the gulf, it's really not that big a deal (this seems to be where we are now; I've read several articles and blog posts in just the past few days throwing around the same statistics some on this very blog have used). Step 5) Hard to tell, but my guess is BP will try to convince everyone that raw crude is actually good for the gulf. Step 6) Even harder to tell, but my guess is BPO will be touting the recuperativce benefits of drinking crude and chewing on tar balls.... ;-)

Speaking of numbers: a mere 100 nanogram (or so) dose of botulinum toxin is enough to kill a 200 pound man. I'll save you the math: that's a ratio of about 1-to-1 trillion. In other words--and to use the breathless prose of the forwarded chain letter repeated in #171--if a man ate a lethal dose of botulinum toxin every day, it would take him more than 2.7 billion years to consume an amount of the toxin equal to his own weight.

As someone else here wrote ealier, numbers can be used in different ways depending on a particular person's agenda. To attempt paint the catastrophe in the gulf as anything but that is disingenuous at best.
Member Since: Posts: Comments:
242. xcool
African wave train Toot toot! is starting
Member Since: September 26, 2009 Posts: 2 Comments: 15684
221. Reported to the admin. It is pointless to use foul words in a foreign language. You can translate anything on Google.
Member Since: Posts: Comments:
The fact we already had a Hurricane with a high ACE shows we are in for an above normal season. People seem to forget that it is only July. They shouldn't just look at 2005 and say this is a slow season, seems to be the problem these days. I'm expecting activity to ramp up in about a week or two.
Member Since: Posts: Comments:
Quoting reedzone:


Yep many smart people came on here last night RIPing the so called hype-2010 season. Yep, guess they must be gods or something, guess this season is really a bust.. Not that I wanted a storm LOL

But it's still July. The hype doesn't start 'til August.
Member Since: Posts: Comments:
TROPICAL WAVE EXTENDS FROM 10N25W TO 19N24W MOVING W AT 15-20
KT. THE WAVE AXIS IS POSITIONED BETWEEN A WEAKENING NORTHERN
VORTEX NW OF THE CAPE VERDE ISLANDS NEAR 18N27W AND A MAXIMUM IN
DEEP LAYER MOISTURE TO THE EAST BETWEEN 18W-24W. BROAD CYCLONIC
TURNING OF THE LOW-LEVEL CLOUD FIELD IS ALSO NOTED ON SATELLITE
BETWEEN 21W-30W IN THE VICINITY OF THE WAVE AXIS. SCATTERED
MODERATE CONVECTION IS FROM 06N-15N BETWEEN 17W-26W.
Member Since: Posts: Comments:
Quoting CybrTeddy:


They pretty much shut up this morning when the Dr's first post in over a week said this season will feature 18-20 named.


Which is extremely reasonable, and if I may add they were the closest on their prediction for the 2006 season. I remember because Adrian (killer, as they call him) showed us this back in May of 2006 when everybody was hyping another 2005 season.
Member Since: Posts: Comments:
Quoting btwntx08:
also the carribean waters are much warmer now than last yr but the gom is a tad cooler than last yr which is wierd


Anomalous warm in the Gulf is common during El Nino years.
Member Since: Posts: Comments:
Quoting reedzone:


Yep many smart people came on here last night RIPing the so called hype-2010 season. Yep, guess they must be gods or something, guess this season is really a bust.. Not that I wanted a storm LOL


They pretty much shut up this morning when the Dr's first post in over a week said this season will feature 18-20 named.
Member Since: Posts: Comments:
Hello,

Have you noticed that the Atlantic Basin Tracking Map is not working?

Member Since: Posts: Comments:
230. 7544
Quoting Chicklit:
Re: Bahama Blob @ 2 p.m.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE TROUGH IS LOCATED OFF THE EASTERN U.S. SEABOARD AND EXTENDS AN UPPER LEVEL TROUGH AXIS TO NEAR 30N74W.
THIS UPPER LEVEL TROUGHING ALONG WITH A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE W ATLC AND GULF OF MEXICO IS PROVIDING FOR AN AREA OF INCREASED MOISTURE AND INSTABILITY GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 20N BETWEEN 65W-80W. THE MOST INTENSE AREA OF ACTIVITY CURRENTLY IS LOCATED OVER THE SE BAHAMAS AND TURKS AND CAICOS ISLANDS FROM 21N-24N BETWEEN 68W-74W.



they note it hmm is moving ne as more convection is building tia
Member Since: Posts: Comments:
Quoting IKE:

The area of disturbed weather in the Southern Bahamas bears watching, IMO.
Member Since: Posts: Comments:
Quoting Baltimorebirds:
Yeah it does.Remember 2009.LoL.


Yep many smart people came on here last night RIPing the so called hype-2010 season. Yep, guess they must be gods or something, guess this season is really a bust.. Not that I wanted a storm LOL
Member Since: Posts: Comments:
Quoting WatchingThisOne:


If your house falls in, you will have bigger problems. I store most of the water in a walk-in space underneath an interior stairwell. Food in a large pantry. First aid kit with the water. And a few bottles of water scattered about the house. I have nothing stored outside. Wouldn't hurt, but rotate any water out there often and protect it from sunlight with a light-colored tarp. High quality filtered water will last longer than tap water.

I do keep some water and food, and a smaller first aid kit, in my vehicle. That is probably the best choice for "outside" if you have room ... you may not be at home when the "big one" hits and getting home may be a challenge.


I have heard of some people who make up a "food torpedo" (a 4 to 6 inch PVC pipe, packed with dry food, first aid stuff, and water purification supplies) and bury that in the yard. As long as the area can be cleared, the "torpedo" should be safe.

I believe they mentioned it at this site...

http://www.theepicenter.com/tow04166.html
Member Since: Posts: Comments:
226. HadesGodWyvern (Mod)
904
TCNA21 RJTD 121800
CCAA 12180 47644 CONSON(1002) 02143 11265 12244 245// 92712=


TY Conson (T1002) System #2
14.3N 126.5E
Dvorak Intensity: T4.5

greater than 65 knots.
Member Since: Posts: Comments:
Re: Bahama Blob @ 2 p.m.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE TROUGH IS LOCATED OFF THE EASTERN U.S. SEABOARD AND EXTENDS AN UPPER LEVEL TROUGH AXIS TO NEAR 30N74W.
THIS UPPER LEVEL TROUGHING ALONG WITH A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE W ATLC AND GULF OF MEXICO IS PROVIDING FOR AN AREA OF INCREASED MOISTURE AND INSTABILITY GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 20N BETWEEN 65W-80W. THE MOST INTENSE AREA OF ACTIVITY CURRENTLY IS LOCATED OVER THE SE BAHAMAS AND TURKS AND CAICOS ISLANDS FROM 21N-24N BETWEEN 68W-74W.
Member Since: Posts: Comments:
Quoting btwntx08:
oh no guess who's back once again ughhh


Dont talk about it...back to weather!
Member Since: Posts: Comments:
Looks like the SAL is weakening, and may be too far to the north to impede development on the impressive wave off of Africa, 97L may be coming soon with this. Other then that, doesn't get any more quieter than this!
Member Since: Posts: Comments:

Viewing: 264 - 214

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.

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron