More pre-season predictions of a very active Atlantic hurricane season
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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This could be a really good day!!! With a lot of hard work in front of all of us!
Oil Spill ROV Windows
it sure was. one of their best!
g'nite :)
Could be "The spirit of the cape verde season" smiling at the favorable conditions this season... (shudder, bad thought that was...)
LOL
The Saw the movie version of the smiley face. That actually could be appropriate .. Hurricanes do look like buzz saws...
We are all family, we respect one another here, we talk tropical weather during Hurricane Season.
Many folks add much here, we have real meteorologists, tropical weather specialists, meteorology students, several very astute young folk under 18. We have folks who love weather here and share and learn.
Those who want to disrespect my family will be reported and Admin will deal with you, as they see fit.
Thanks!
Funny you've had all that rain - we haven't had that much, relatively speaking.
Do you know how much time JFV has to spend getting new emails, new names, etc? How can anyone spend that much time doing that stuff? And this has been going on for what, 3 years?
Would the SAL keep ocean temp's down a few deg's sure appears that way right now to me anyway.
Nice post -- since we don't have blog police, it would be nice if people stopped thinking that they can come in and correct others.
Yes, Geoff, quite familiar with that station. It has been run by Dr. Geflerken for many years now. There is talk he may retire and Lars Sturlerderken may replace him. It has been quite a stir there, since the volcano and everything as you know.
Very easily. The current quiet period is wholly irrelevant.
Yeah, it does.
Agreed - nerve racking. One of my most vivid memories was sitting at my dining room table listening to the radio broadcasts - about midmorning the first day. They were talking about the zoo being flattened, no food for the animals, the airbase being destroyed. Remember wondering if we would have a business, anyway to support 4 kids, and if everyone we knew was alive. Very eery.
Thought so, that would make since with this.
Yep. But 2006 had very warm SSTs as well, despite this fact. Same with 2005.
It does so by preventing sunlight from reaching the ocean surface.
Sorry, wrong date.
Looks like they're shifting the scale to have a max of 34C now. Things don't "look" quite as bad that way. Don't these sea temp maps usually top out at 32C?
what video link.
I remember waking up the next day and my dad breaking out the battery operated TV and shouting to my mom OMG! They couldnt believe how flat everything was. It was scary as we were isolated where we lived since most all the trees were down. There was a camper on a house nearby no one knew where it came from.
You're right Geoff, shouldn't be talking about the Norwegian satellite station. But thought you might be interested since you posted the image from the St. Olaf obseratory.
The took the SST's off of the Southwest and Southeast coastal waters and they were near 90 deg. Unheard of this early. High temps all the way up to just South of Lake Worth, but nothing really happens up there anyway. Just take a look at the map on WU and you can see the temps.
ST. OLAF?
July 12, 2010 - 10:50 PM EDT - The Atlantic Remains Quiet - Outlook
If you look back in yesterdays blogs, there is about 2 hours worth of Hurricane Andrew videos. They were posting all day. Interesting videos. I was in Old Cutler at the time. (Not yesterday, during Andrew)
But I need to know - will Lars Sturlerderken be a suitable replacement???
well its better than reading 100 post abouy the jv dude lol
you meant 1998
I dont know enough about it to give a correct answer but it looks like 34C
I'm sorry, but that was awesome.
July 12, 2010 - 10:50 PM EDT - The Atlantic Remains Quiet - Outlook
Here ya go Baltimorebirds.... It was a few hours ago and is gone now
137 and Kendall Dr. Just north of Tamiami Airport
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