Average hurricane season foreseen by CSU, NOAA, and TSR

By: Dr. Jeff Masters , 4:45 PM GMT on June 02, 2009

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A near-average Atlantic hurricane season is on tap for 2009, according to the seasonal hurricane forecast issued June 2 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 11 named storms, 5 hurricanes, and 2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 88% of average. Between 1950 - 2000, the average season had 10 named storms, 6 hurricanes, and 2 intense hurricanes. But since 1995, the beginning of an active hurricane period in the Atlantic, we've averaged 15 named storms, 8 hurricanes, and 4 intense hurricanes per year. The new forecast is a step down from their April forecast, which called for 12 named storms, 6 hurricanes, and 2 intense hurricanes. The new forecast calls for a near-average chance of a major hurricane hitting the U.S., both along the East Coast (28% chance, 31% chance is average) and the Gulf Coast (28% chance, 30% chance is average). The Caribbean is also forecast to have an average risk of a major hurricane.

The forecasters cited several reasons for an average season:

1) Sea surface temperature (SST) anomalies in the tropical Atlantic are quite cool. In fact, these SST anomalies are at their coolest level since July 1994. Cooler-than-normal waters provide less heat energy for developing hurricanes. In addition, an anomalously cool tropical Atlantic is typically associated with higher sea level pressure values and stronger-than-normal trade winds, indicating a more stable atmosphere with increased levels of vertical wind shear detrimental for hurricanes. Substantial cooling began in November 2008 (Figure 1), primarily due to a stronger than average Bermuda-Azores High that drove strong trade winds. These strong winds increased the mixing of cool waters to the surface from below, and caused increased evaporational cooling.

2) Hurricane activity in the Atlantic is lowest during El Niño years and highest during La Niña or neutral years. This occurs because El Niño conditions bring higher wind shear over the tropical Atlantic. The CSU team expects the current neutral conditions may transition to El Niño conditions (70% chance) by this year's hurricane season. I discussed the possibility of a El Niño conditions developing this year in a blog posted Friday.


Figure 1. Change in Sea Surface Temperature anomaly between November 2008 and 2009. Most of the Atlantic has cooled significantly, relative to normal, over the past 7 months. Image credit: NOAA/ESRL.

Analogue years
The CSU team picked five previous years when atmospheric and oceanic conditions were similar to what we are seeing this year: neutral to slightly warm ENSO conditions, slightly below-average tropical Atlantic SSTs, and above-average far North Atlantic SSTs during April-May. Those five years were 2002, which featured Hurricane Lili that hit Louisiana as a Category 1 storm; 2001, featuring Category 4 storms Michelle, which hit Cuba, and Iris, which hit Belize; 1965, which had Category 3 Betsy that hit New Orleans; 1960, which had two Category 5 hurricanes, Ethyl and Donna; and 1959, which had Category 3 Hurricane Gracie, which hit South Carolina. The mean activity for these five years was 10 named storms, 6 hurricanes, and 2 intense hurricanes, almost the same as the 2009 CSU forecast.

How accurate are the June forecasts?
The June forecasts by the CSU team have historically offered a skill of 20 - 30% higher than a "no-skill" forecast using climatology (Figure 2). This is a decent amount of skill for a seasonal forecast, and these June forecasts can be useful to businesses such as the insurance industry and oil and gas industry that need to make bets on how active the coming hurricane season will be. This year's June forecast uses the same formula as last year's June forecast, which did quite well predicting the 2008 hurricane season (prediction: 15 named storms, 8 hurricanes, 4 intense hurricanes; observed: 16 named storms, 8 hurricanes, 5 intense hurricanes). An Excel spreadsheet of their forecast skill (expressed as a mathematical correlation coefficient) show values from 0.44 to 0.58 for their June forecasts, which is respectable.


Figure 2. Accuracy of long-range forecasts of Atlantic hurricane season activity performed at Colorado State University (CSU) by Dr. Bill Gray's team (colored squares) and Tropical Storm Risk, Inc. (TSR, colored lines). The skill is measured by the Mean Square Skill Score (MSSS), which looks at the error and squares it, then compares the percent improvement the forecast has over a climatological forecast of 10 named storms, 6 hurricanes, and 2 intense hurricanes. TS=Tropical Storms, H=Hurricanes, IH=Intense Hurricanes, ACE=Accumulated Cyclone Energy, NTC=Net Tropical Cyclone Activity. Image credit: TSR.

NOAA's 2009 hurricane season forecast
The National Oceanic and Atmospheric Administration (NOAA), issued its 2009 Atlantic hurricane season forecast on May 21. NOAA anticipates that an average season it most likely, giving a 50% chance of a near-normal season, 25% chance of an above-normal season, and a 25% chance of a below-normal season. They give a 70% chance that there will be 9 - 14 named storms, 4 - 7 hurricanes, 1 - 3 major hurricanes, and an Accumulated Cyclone Energy (ACE) in the 65% - 130% of normal range. The forecasters cited the following main factors that will influence the coming season:

1) We are in an active period of hurricane activity that began in 1995, thanks to a natural decades-long cycle in hurricane activity called the Atlantic Multidecadal Oscillation (AMO).

2) There will either be an El Niño event or neutral conditions in the Equatorial Eastern Pacific. An El Niño event should act to reduce Atlantic hurricane activity. However, our skill at predicting an Niño in late May/early June is poor, so there is high uncertainty about how active the coming hurricane season will be.

3) Cooler-than-average SSTs are currently present in the eastern tropical Atlantic. These cool SSTs are forecast to persist through into August-September-October (ASO). ASO SSTs in the eastern tropical Atlantic have not been below average since 1997. Cooler SSTs in that region are typically associated with a reduction in Atlantic hurricane activity.

Thus, they expect that even though we are in an active hurricane period, the presence of an El Niño or cool SSTs in the eastern Atlantic could easily suppress activity, making a near-average season the most likely possibility. They note that two promising computer models, the NOAA CFS model and the European Center for Medium-Range Weather Forecasts (ECMWF) Global Climate Model System 3, both forecast the possibility of a below-average hurricane season.

2009 Atlantic hurricane season forecast from Tropical Storm Risk, Inc.
The British private forecasting firm Tropical Storm Risk, Inc. (TSR) has joined the ranks of NOAA and Colorado State University in calling for near-average activity. The latest TSR forecast issued June 4 calls for 10.9 named storms, 5.2 hurricanes, 2.2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 72% of average. The storm numbers are close to the 50-year average of 10 named storms, 6 hurricanes, and 2 intense hurricanes, and are sharp reduction from their April forecast of 15 named storms, 7.8 hurricanes, and 3.6 intense hurricanes. TSR predicts a 50% chance that this season will be in the bottom 1/3 of years historically, and a 40% chance that U.S. landfalling activity will be in the lowest 1/3 of years historically. TSR gives a 32% chance of a near-normal season, and a 17% chance of a below normal season. TSR rates their skill level as 26% above chance at forecasting the number of named storms, 15% skill for hurricanes, and 19% skill for intense hurricanes.

TSR projects that 3.2 named storms will hit the U.S., with 1.3 of these being hurricanes. The averages from the 1950-2008 climatology are 3.2 named storms and 1.5 hurricanes. Their skill in making these April forecasts for U.S. landfalls is 7 - 18% above chance. In the Lesser Antilles Islands of the Caribbean, TSR projects 0.9 named storms, 0.4 of these being hurricanes. Climatology is 1.1 named storms and 0.5 hurricanes.

TSR cites two main factors for their reduced forecast: a large and unexpected cooling of sea surface temperatures in the tropical Atlantic, and warmer SSTs in the Equatorial Eastern Pacific (which might lead to an El Niño event that will bring high wind shear to the Atlantic). TSR expects faster than than normal trade winds from July - September over the Main Development Region (MDR) for hurricanes over the Atlantic (the region between 10° - 20° N from Central America to Africa, including all of the Caribbean). Trade winds are forecast to be 0.83 meters per second (about 1.7 mph) faster than average in this region, which would create less spin for developing storms, and allow the oceans to cool down, due to increased mixing of cold water from the depths and enhanced evaporational cooling. TSR forecasts that SSTs will cool an additional 0.3°C compared to average over the MDR during hurricane season.

Air France crash
The Air France Flight 447 A330 aircraft that disappeared over the mid-Atlantic Ocean yesterday definitely crossed through a thunderstorm complex near the Equator, according to a detailed meteorological analysis by Tim Vasquez. He concludes that "the A330 would have been flying through significant turbulence and thunderstorm activity for about 75 miles (125 km), lasting about 12 minutes of flight time" but that "complexes identical to this one have probably been crossed hundreds of times over the years by other flights without serious incident". See also the excellent CIMSS satellite blog for more images and analysis of the weather during the flight.

Invest 92
NHC is tracking a storm near the Azores Islands (Invest 92L) that is probably the remnants of the core of an extratropical cyclone that closed off some warm air at the center. The system has developed some heavy thunderstorm activity near its center, making this a hybrid storm. However, with ocean temperatures near 62°F (16°C), this storm has little chance of becoming a named subtropical storm.

Jeff Masters

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662. Floodman
6:59 PM GMT on June 03, 2009
634.

Good to be seen...and I'm glad to see the Keeper is here...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
661. all4hurricanes
6:57 PM GMT on June 03, 2009
Quoting SomeRandomTexan:
92L does look SubTropical in nature... impressive for where it is at...

I was about to say that myself

East pacific looks like it's acting up
Member Since: March 29, 2008 Posts: 0 Comments: 2375
660. IKE
6:57 PM GMT on June 03, 2009
Quoting NRAamy:
IKE...yeah, I almost peed my pants too..thank goodness for Depends...

;)


LOL.

You must to have gotten some from that female Astronaut?
Member Since: June 9, 2005 Posts: 23 Comments: 37860
659. Floodman
6:57 PM GMT on June 03, 2009
651
Good to be back! How have you been?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
658. PensacolaDoug
6:54 PM GMT on June 03, 2009
Quoting StormSurgeon:


Wow! Haven't heard the name Danny Treanor in a long time. He was the weatherman for WALA here in Mobile for many years (maybe a decade)and he also hosted "Diling for Dollars". It's good to know where he is now.



Ditto!

Remember the WALA tagline?

If you know Trainor, (sp?) you know the weather!
Member Since: July 25, 2006 Posts: 0 Comments: 660
657. NRAamy
6:51 PM GMT on June 03, 2009
IKE...yeah, I almost peed my pants too..thank goodness for Depends...

;)
Member Since: January 24, 2007 Posts: 317 Comments: 31946
656. SomeRandomTexan
6:51 PM GMT on June 03, 2009
92L does look SubTropical in nature... impressive for where it is at...
Member Since: August 30, 2007 Posts: 0 Comments: 1857
655. IKE
6:50 PM GMT on June 03, 2009
Quoting NRAamy:
JERRY!!!!!!!!!!!!!

My man! Gald to see you back, dude!!!!!

:)


You so glad you misspelled glad.

OOPS!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
654. MrstormX
6:50 PM GMT on June 03, 2009
Suprised 92L isn't dead yet looking very subtropical in nature

Member Since: May 27, 2009 Posts: 0 Comments: 4438
653. SevereHurricane
6:49 PM GMT on June 03, 2009
Quoting HURRICANECAT5:
LOOKS LIKE NEXT WEEK WILL BE INTERESTIGN IN THE NW CARRIBBEAN. COULD THIS BE ANA?


Wow,
LOL...
Member Since: September 7, 2008 Posts: 17 Comments: 1604
652. SomeRandomTexan
6:49 PM GMT on June 03, 2009
Another strong line of storms approaching the SeTx areas... I guess a repeat of yesterday
Member Since: August 30, 2007 Posts: 0 Comments: 1857
651. NRAamy
6:49 PM GMT on June 03, 2009
JERRY!!!!!!!!!!!!!

My man! Gald to see you back, dude!!!!!

:)
Member Since: January 24, 2007 Posts: 317 Comments: 31946
Just wanted to inform everyone that the CCHS Weather Center website has finally been updated with new forecasts and a new Graphical Tropical Update.
Member Since: Posts: Comments:
649. IKE
Quoting StormSurgeon:


Seems like a long time ago doesn't it. I hope the weather services are right and this gulf mess is shoved on out tomorrow evening by the approaching front and leaves us with a few nice days. I see on radar you're getting hit pretty good about now.


Yup...rain and 71 degrees.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
648. IKE
Quoting sporteguy03:


He works at Central Florida News 13, A quirky weather man always makes weather sound interesting. He also supports pet adoption good man!


He is good on-air.

Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:


I remember him...brown hair...thin man.


Seems like a long time ago doesn't it. I hope the weather services are right and this gulf mess is shoved on out tomorrow evening by the approaching front and leaves us with a few nice days. I see on radar you're getting hit pretty good about now.
Member Since: September 1, 2007 Posts: 0 Comments: 1793
Quoting IKE:


I remember him...brown hair...thin man.


He works at Central Florida News 13, A quirky weather man always makes weather sound interesting. He also supports pet adoption good man!
Member Since: July 7, 2005 Posts: 0 Comments: 5417
645. IKE
Quoting StormSurgeon:


Wow! Haven't heard the name Danny Treanor in a long time. He was the weatherman for WALA here in Mobile for many years (maybe a decade)and he also hosted "Diling for Dollars". It's good to know where he is now.


I remember him...brown hair...thin man.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting Floodman:
I'm glad to see the usual suspects are here: NEwx, stillwaiting, atmoaggie...

Hey, atmo, have you heard the bootleg "Teddy Bear's Picnic" live with Zappa and Captain Beefheart?


No, but that sounds very interesting. Link, perchance?
Member Since: Posts: Comments:
Hey Flood, I'm here too! Good to see ya!
Member Since: September 3, 2007 Posts: 3 Comments: 1519
I'm glad to see the usual suspects are here: NEwx, stillwaiting, atmoaggie...

Hey, atmo, have you heard the bootleg "Teddy Bear's Picnic" live with Zappa and Captain Beefheart?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
I'm good, guys...I get very busy in the winters when there's been a hurricane make landfall; things are slowing enough now that I can jump back in, at least for a litlle while...I'm doing a number of tech upgrades soon that should burn up my spare time LOL
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Hey Casey Jones. Been driving that train or what?

We have been having a teddy bear's picnic almost daily in here.
Member Since: Posts: Comments:
Quoting leftovers:
danny traner from our cent. florida weather station said he's watching the low near panama. he said it could hang around and gather some precip. happy weather


Wow! Haven't heard the name Danny Treanor in a long time. He was the weatherman for WALA here in Mobile for many years (maybe a decade)and he also hosted "Diling for Dollars". It's good to know where he is now.
Member Since: September 1, 2007 Posts: 0 Comments: 1793
Anybody know what's happening over at the NationalSnow&IceDataCenter?
I keep getting a "taking too long to respond" message.
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Quoting IKE:


LOL.

Yeah a Cat 6 headed for New Orleans lol
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636. IKE
Quoting KEEPEROFTHEGATE:
maybe a cat 6 then you can write in all caps 24 hrs aday

lol


LOL.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Flood!!!,how the heck have you been????,we've missed the humor during the off-season,everything OK???
Member Since: Posts: Comments:
good to see the floodman
Member Since: Posts: Comments:
Quoting HURRICANECAT5:
LOOKS LIKE NEXT WEEK WILL BE INTERESTIGN IN THE NW CARRIBBEAN. COULD THIS BE ANA?
maybe a cat 6 then you can write in all caps 24 hrs aday

lol
Member Since: Posts: Comments:
Floodman,good to see you,how has life been treating you.
Member Since: September 6, 2007 Posts: 888 Comments: 15984
This is the most compact I've seen 92L looking, looks tropical in nature , if it doesn't get named by 5-8 pm tonight well its lost its chance though I doubt it will get named.
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Howdy folks...covering a lot of ground in here today, huh?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
LOOKS LIKE NEXT WEEK WILL BE INTERESTIGN IN THE NW CARRIBBEAN. COULD THIS BE ANA?
Member Since: Posts: Comments:
Quoting palmbaywhoo:
Link

FEMA is looking at putting Florida's Foreclosure Crisis to good use. Intresting article on what may happen if a Katrina type storm hits Florida and what their options are for keeping people close to their homes....


I don't like the idea.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Link

FEMA is looking at putting Florida's Foreclosure Crisis to good use. Intresting article on what may happen if a Katrina type storm hits Florida and what their options are for keeping people close to their homes....
Member Since: Posts: Comments:
626. IKE
I have a thunderstorm outside my house...inland Florida panhandle.

Thunderstorm and 72.3 degrees.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
625. Skyepony (Mod)
I saw where a 3 mile long debri field was found. No coordinates but there is a cluster of ships around where the ITCZ had gone off.

Around 0-5N 30W
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What a mess! Not good sail boat weather.
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Photobucket
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Quoting Vortex95:
with inflation the average hosue would cost a million in 2080 heh...


Try 2012
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Latest TPC surface forecasts:






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617. MahFL
Patrap....2080 ? I'll be dead by then, lol.
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616. MahFL
If it was a bomb someone would have claimed responsibility.
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Hurricane Berry strikes Brownsville during a preparedness drill

June 2, 2009 - 9:23 PM

This year is the drill called for a Catergory 3 hurricane named Berry to strike Brownsville with 120-mph winds and cause significant structural damage and casualties both human and animal, said Cameron County Emergency Management Coordinator Johnny Cavazos.

"Basically Dolly and Ike changed the way we look at Category 2 hurricanes," Cavazos said referring to hurricanes relatively low in the severity scale. "The rules have changed."

Dolly and Ike where both Category 2 hurricanes; Dolly caused extensive water damage in the Rio Grande Valley and Ike ravaged the Galveston area, he said.

"Everyone, from the National Weather Service to the local emergency management officers, no longer takes Category 2 hurricanes lightly, anymore," Cavazos said.
Member Since: July 3, 2005 Posts: 428 Comments: 129780
Gov. Crist urges Floridians to get ready for hurricane season
By Stephen D. Price • Florida Capital Bureau • June 3, 2009

Gov. Charlie Crist gave a pep talk to workers at the Florida Emergency Operations Center today and reminded Floridians to update their disaster plans.
Member Since: July 3, 2005 Posts: 428 Comments: 129780
Quoting Patrap:
Oil Companies Prepared Despite Mild Hurricane Outlook


The 2009 Atlantic hurricane season officially began Monday and runs through Nov. 30. According to Reuters, experts predict it will be a quieter season than last, when 16 tropical storms and hurricanes formed in the Atlantic, Caribbean and Gulf of Mexico.


But, Shell, the largest natural gas producer and second largest oil producer in the Gulf region, isn’t betting on the forecast. "We prepare for the worst and hope for the best," said Frank Glaviano, vice president of Shell's U.S. offshore operations. The Gulf accounts for 15 percent of U.S.-produced natural gas and 25 percent of domestic crude oil output, according to Reuters.

Analysts told Reuters the oil industry learned vital lessons since Hurricanes Ivan in 2004, Katrina and Rita in 2005, and Gustav and Ike in 2008. And a global recession has relieved pressure on what for much of 2008 was a drum-tight U.S. oil and refined product distribution system with virtually no extra supply, according to the Reuters report.


I was very glad to see Citgo and Starbucks were kicked off the Florida Turnpike rest stops. They will be replaced entirely by Shell Oil and Dunkin Doughnuts.
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Study: Warming to worsen hurricane damage in Texas
Posted 6/1/2009 5:38 PM

By Juan A. Lozano, Associated Press Writer


The study projected that rising sea levels and more intense hurricanes, due to global warming, will increase structural damage to homes and buildings from a major hurricane in Corpus Christi by 60% to 100% in about 20 years and by more than 250% by the 2080s.

Such a catastrophic storm surge event would translate into projected damage increases of between $100 million to $250 million in around 20 years and of between $250 million and more than $1 billion by the 2080s.

But Irish said such potential damage could happen anywhere along the Texas Gulf Coast and even the rest of the U.S. Gulf Coast due to global warming, in which carbon dioxide and other gases added to the air by industrial and other activities have been blamed for rising global temperatures. This has increased worries about possible major changes in weather and climate.
Member Since: July 3, 2005 Posts: 428 Comments: 129780

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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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