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: 164 - 114

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

Quoting BFG308:
Tampa Tom- I got similar numbers. It doesn't take a chemical engineer to use wikipedia and a calculator to make some great approximations


I call it 'Kentucky Windage' :-)

Wiki sez 32,000,000 gallons for The Valdez... Ruffly 3.5% of the volume of the Superdome...
Member Since: Posts: Comments:
Hi Jeff, I'm a little north of Bethune, on the treed end of the island (as opposed to North Beach!).
Yes, this is our second good day for rain.
We've needed it.
Member Since: Posts: Comments:
162. MahFL
Quoting StormW
"An area of thunderstorms is noted in satellite imagery this morning over the southern Bahamas. Based on current and forecast wind shear maps, I am not expecting anything to become of this, as well as the large amount of drier air (noted in orange) moving in from the west."

I see no orange coming in from the West towards the Bahamas......
Member Since: Posts: Comments:
Quoting Chicklit:
By the way, anyone care to describe what is going on down in the Bahamas?!

I cannot read back in the blog because I am setting up a new laptop. Crazy. Need I say more.



Upper level divergence assoiciated w/a weakening TUTT...in other words NOTHING!!!
Member Since: Posts: Comments:
Quoting truecajun:


i thouht exxon valdez spilled 10 million and that dwh is already 20 exxon valdez, so we r at 200,000,000 gallons


so no, it hasn't filled the superdome.
Member Since: Posts: Comments:
Quoting btwntx08:
besides theres no vitocity with it either


Just looked at the Shear its....25kts.
Member Since: Posts: Comments:
158. IKE
12Z NOGAPS.....looks like high pressure is over the GOM...weakens and then rebuilds through the next 7 1/2 days.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
The latest Bahamian blob looks like a dandy.
Baha should be on here soon.
Member Since: Posts: Comments:
Quoting TampaTom:


Some quick scratch paper calculations:

There are 264.17 gallons per cubic meter.
The Louisiana Superdome has an an internal volume of 3,500,000 cubic meters

The Exxon Valdez spilled 32,000,000 gallons.

That equals 121,134 cubic meters... less than the Superdome.

Of course, I'm getting my info from Wikipedia and I was an English major. Do the math...


i thouht exxon valdez spilled 10 million and that dwh is already 20 exxon valdez, so we r at 200,000,000 gallons
Member Since: Posts: Comments:
Tampa Tom- I got similar numbers. It doesn't take a chemical engineer to use wikipedia and a calculator to make some great approximations
Member Since: Posts: Comments:
152. IKE
Quoting Jeff9641:


Did you notice the developement of a CV on the last frame?


Yeah.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
NFL opener Invest Sept 9
Member Since: Posts: Comments:
Back on the home front.... this covers most of SE part of The Old North State..



Severe Thunderstorm Watch
Statement as of 1:15 PM EDT on July 12, 2010


Severe Thunderstorm Watch 458 is in effect until 900 PM EDT

NC
. North Carolina counties included are

Anson Bladen Brunswick
Chatham Columbus Cumberland
Davidson Harnett Hoke
Johnston Lee Montgomery
Moore New Hanover Pender
Randolph Richmond Robeson
Sampson Scotland Stanly
Union wake Wayne
Wilson
Member Since: Posts: Comments:
149. IKE
Quoting Jeff9641:


It's about time to buckle up.


Member Since: June 9, 2005 Posts: 23 Comments: 37860
146. IKE
SYNOPSIS FOR THE GULF OF MEXICO
1030 AM CDT MON JUL 12 2010

.SYNOPSIS...A RIDGE ALONG 25N WILL SHIFT N TO ALONG 27N TUE THEN
TO ALONG 29N THU AND FRI.


SYNOPSIS FOR CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W
1130 AM EDT MON JUL 12 2010

.SYNOPSIS...A TROPICAL WAVE ALONG 83W WILL MOVE W THROUGH THE W
CARIBBEAN THROUGH TONIGHT MOVING INLAND TUE. ANOTHER TROPICAL
WAVE WELL E OF THE AREA WILL APPROACH 55W EARLY WED THEN WILL
MOVE ACROSS THE TROPICAL N ATLC WED NIGHT AND THROUGH THE E
CARIBBEAN THU AND FRI.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
145. unf97
Quoting Chicklit:
thanks, unf. we've got thunderboomers here in ecfl again today. yippee. and again, that wave by CV is crazy huge and still vader-like.


You are welcome. Also, we are currently having heavy thunderstorms roll through the Jax metro area. Stormy afternoon for sure.
Member Since: Posts: Comments:
Quoting Neapolitan:


True that. And for further reference purposes: fish can extract oxygen from water; water doesn't need to be scrubbed off of surfaces with detergent and a brush; water doesn't leave blobs of gooey, sticky tar in and on beach sand; birds can fly with water on their wings; fish and turtle eggs layed in and around water will oftentimes hatch; beaches are seldom closed to visitors due to pollution by water; nobody needs a HazMat suit to work with water...


Yes. And this line of argument (the Gulf is so big) has always sounded to me like "the area affected by Chernobyl is nothing compared to the land mass of Asia."
Member Since: July 15, 2005 Posts: 3 Comments: 1270
Quoting Jeff9641:


Just a trough of low pressure with persistant thunderstorms for right now but needs to be watched.


tail end of a trough (dangerdanger)

lovely pouring rain here
Member Since: Posts: Comments:
sorry - duplicate post...
Member Since: Posts: Comments:
139. IKE
12Z CMC aiming another one at the Yucatan.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting 7544:
thanks something tring to brew around the bahammas today that blob tia ?

Link


Na...nothing there to worry about......Shear is 30kts.....with no Vorticity really at all with mainly upper level Divergence caused by a trough that extends NNE of the blob. No worries.
Member Since: Posts: Comments:
Quoting truecajun:


someone told me that the amount of oil released into the GOM wouldn't fill the superdome. i find this hard to believe. has anyone else heard this?


Some quick scratch paper calculations:

There are 264.17 gallons per cubic meter.
The Louisiana Superdome has an an internal volume of 3,500,000 cubic meters

The Exxon Valdez spilled 32,000,000 gallons.

That equals 121,134 cubic meters... less than the Superdome.

Of course, I'm getting my info from Wikipedia and I was an English major. Do the math...
Member Since: Posts: Comments:
Quoting DestinJeff:


another case of the classic promise of "next week" from the tropics.


Sort of 'Tune in next week when we all start ooooooh and aaaaaaah.'

But it does seem like the real season will soon be here. i do not like what i see coming off Africa now but it is too early to place any faith in cyclogenesis per the modesl. Time will tell though.
Member Since: Posts: Comments:
thanks, unf. we've got thunderboomers here in ecfl again today. yippee. and again, that wave by CV is crazy huge and still vader-like.
Member Since: Posts: Comments:
bbl. i'm going school uniform shopping. mixed feelings - glad they are going back, but it's not fun dropping almost a grand on uniforms : 0
Member Since: Posts: Comments:
By the way, anyone care to describe what is going on down in the Bahamas?!

I cannot read back in the blog because I am setting up a new laptop. Crazy. Need I say more.
Member Since: Posts: Comments:
130. unf97
Quoting 7544:
thanks something tring to brew around the bahammas today that blob tia ?

Link


The showers and thunderstorms in the SE Bahamas is associated with an upper level trough. Development is not expected in that region for the short term.
Member Since: Posts: Comments:
Quoting Chicklit:
I am so glad to see Dr. Masters is back!
I must admit Dr. Carver's last blog was a little bit like putting the children in front of the tv set...rofl. Anyway, he's a good sport but there is no one like JM!

Very interesting post, particularly the following:
...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.


LOL! agreed - he just gave us something to chew on. i don't blame him since there was not much to talk about
Member Since: Posts: Comments:
I am so glad to see Dr. Masters is back!
I must admit Dr. Carver's last blog was a little bit like putting the children in front of the tv set...rofl. Anyway, he's a good sport but there is no one like JM!

Very interesting post, particularly the following:
...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.
Member Since: Posts: Comments:
Quoting BFG308:


Nah, that'd be misleading, because of course the oil is not equally distributed through, or even on top of, the entire GOM. DWH has surpassed Ixtoc 1 spill from '79-'80. That gusher took 10 months to stop, and the effects of the oil are still being determined. Wikipedia says some of the oil is still out there. Of course that was Pemex (national oil company not financially responsible for claims), and the 70's, so I personally doubt clean-up efforts were very intensive.


someone told me that the amount of oil released into the GOM wouldn't fill the superdome. i find this hard to believe. has anyone else heard this?
Member Since: Posts: Comments:
ECMWF 00z 72 hours out. Hinting at cyclogenesis off CV.


Nothing too well organized, but shows a well organized wave.
Member Since: Posts: Comments:
122. 7544
thanks something tring to brew around the bahammas today that blob tia ?

Link
Member Since: Posts: Comments:
Quoting LightningCharmer:
I guess, someone will now determine, calculate or estimate how many parts per billion, million perhaps thousand, the spill is in comparison the GOM.


Nah, that'd be misleading, because of course the oil is not equally distributed through, or even on top of, the entire GOM. DWH has surpassed Ixtoc 1 spill from '79-'80. That gusher took 10 months to stop, and the effects of the oil are still being determined. Wikipedia says some of the oil is still out there. Of course that was Pemex (national oil company not financially responsible for claims), and the 70's, so I personally doubt clean-up efforts were very intensive.
Member Since: Posts: Comments:
if the average is right, 13 hurricanes will surely keep us busy, unless a lot of them are fish storms
Member Since: Posts: Comments:
The CMC and NGP both develop a Cyclone in the SW Caribbean in 4-5 days.....while the GFS also tried to develop something but, the energy got transferred into the Pacific by a developing system......SOMETHING TO WATCH over the next few days.
Member Since: Posts: Comments:
116. unf97
Good afternoon everyone.

Welcome back Dr. Masters and thanks for your update. I hope everyone is having a great Monday. The tropics are quiet for the moment, but I anticipate this lull ending within the next week or so.
Member Since: Posts: Comments:
the average of the 7 forecasts listed by dr. masters is 17.7 named storms and 12.6 hurricanes. for the hurricanes, i averaged only the last five forecasts because the first 2 predicted total named storms only.
Member Since: Posts: Comments:
114. 7544
Quoting TampaSpin:
Tropical Update
Posted by TampaSpin on July 12, 2010 at 12:30 PM




The blue circles are areas of Interest by me and not by the NHC!!!


looks right with the cmc showing is tyhe africa wave the one the cmc shows for so fla at 144 tia tampa

Link
Member Since: Posts: Comments:

Viewing: 164 - 114

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.

Local Weather

Overcast
47 °F
Overcast

JeffMasters's Recent Photos

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