CSU predicts highly active hurricane season; Cyclone Phet approaching Oman

By: Dr. Jeff Masters , 2:00 PM GMT on June 03, 2010

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A very active Atlantic hurricane season is on tap for 2010, 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 18 named storms, 10 hurricanes, and 5 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 185% 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 14 named storms, 8 hurricanes, and 4 intense hurricanes per year. The new forecast is a step up from their April forecast, which called for 15 named storms, 8 hurricanes, and 4 intense hurricanes. The new forecast calls for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (51% chance, 31% chance is average) and the Gulf Coast (50% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also high, at 65% (42% is average.) This is the most aggressive early June forecast ever issued by the CSU group; the previous most aggressive such forecasts were for the 2006 and 2007 seasons, when the CSU team predicted 17 named storms, 9 hurricanes, and 5 intense hurricanes. Both of these forecasts did poorly, particularly the 2006 forecast, as only 10 named storms, 5 hurricanes, and 2 intense hurricanes were observed.

The forecasters cited four main reasons for an active season:

1) Weak La Niña conditions should develop by the most active portion of this year's hurricane season (August-October). The expected trend towards weak La Niña conditions should lead to reduced levels of vertical wind shear compared with what was witnessed in 2009.

2) Current SST anomalies are running at near-record warm levels. These very warm waters are associated with dynamic and thermodynamic factors that are very conducive for an active Atlantic hurricane season.

3) A weaker-than-normal Azores High prevailed during April-May. Weaker high pressure typically results in weaker trade winds that are commonly associated with more active hurricane seasons.

4) We are in the midst of a multi-decadal era of major hurricane activity, which began in 1995. Major hurricanes cause 80-85 percent of normalized hurricane damage.

Analogue years
The CSU team picked four previous years when atmospheric and oceanic conditions were similar to what we are seeing this year: weak El Niño to neutral conditions, well above-average tropical Atlantic SSTs, and above-average far North Atlantic SSTs during April - May. Those four years were 2005, the worst hurricane season of all time; 1969, the 3rd worst hurricane season of all time, featuring Category 5 Hurricane Camille which hit Mississippi; 1966, a relatively average year that featured Category 4 Inez that killed 1,000 people in Haiti; and 1958, a severe season with 5 major hurricanes. The mean activity for these five years was 17 named storms, 10 hurricanes, and 5 intense hurricanes, almost the same as the 2009 CSU forecast.

How accurate are the June forecasts?
The June forecasts by the CSU team over the past 12 years have had a skill 19% - 30% higher than a "no-skill" climatology forecast for number of named storms, number of hurricanes, and the ACE index (Figure 1). 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. Unfortunately, the CSU June 1 forecasts do poorly at forecasting the number of major hurricanes (only 3% skill), and major hurricanes are what do 80 - 85% of all hurricane damage (normalized to current population and wealth levels.) This year's June forecast uses the same formula as the past two years, 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) and 2009 hurricane season (prediction: 11 named storms, 5 hurricanes, 2 intense hurricanes; observed: 9 named storms, 3 hurricanes, 2 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 1. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 1999-2009 (May) and 1998-2009 (August), using the Mean Squared Error. The British firm Tropical Storm Risk (TSR) will issue their outlook for the 2010 Atlantic hurricane season on June 4. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

NOAA's 2010 hurricane season forecast
NOAA issued their forecast for the upcoming Atlantic hurricane season last week. As I discussed in my post on their forecast, NOAA is calling for very active and possibly hyperactive season. They give an 85% chance of an above-normal season, a 10% chance of a near-normal season, and just a 5% chance of a below-normal season. NOAA predicts a 70% chance that there will be 14 - 23 named storms, 8 - 14 hurricanes, and 3 - 7 major hurricanes, with an Accumulated Cyclone Energy (ACE) in the 155% - 270% of normal range. If we take the midpoint of these numbers, NOAA is calling for 18.5 named storms, 11 hurricanes, 5 major hurricanes, and an ACE index 210% of normal. A season with an ACE index over 175% is considered "hyperactive."


Figure 2. Visible satellite image of Tropical Cyclone Phet on Thursday, June 3, 2010.

Tropical Cyclone Phet the 2nd strongest Arabian Sea storm on record
Record heat over southern Asia in May has helped heat up the Arabian Sea to 2°C above normal, and the exceptionally warm SSTs helped fuel Tropical Cyclone Phet into the second strongest tropical cyclone ever recorded in the Arabian Sea. Phet peaked at Category 4 strength with 145 mph winds yesterday, and has weakened slightly to 135 mph winds this morning. Only Category 5 Cyclone Gonu of 2007, which devastated Oman, was a stronger Arabian Sea cyclone.

Phet is over very warm waters of 30 - 31°C, and is under moderate wind shear of 10 - 20 knots. However, the storm is wrapping in dry air from the Arabian Peninsula, which has caused weakening. Visible satellite imagery from this morning (Figure 2) shows that the heavy thunderstorms on the north side of Phet have been eroded away by dry air. Phet is a small storm, and could fall apart fairly quickly if dry air can penetrate into its core. This should happen later today, since wind shear is on the increase, and the shearing winds should be able to disrupt the circulation enough that dry air can force its way into Phet's eyewall. Phet is fairly small, will miss the most heavily populated areas of Oman, and will likely undergo significant weakening before landfall, so the storm is unlikely to cause the kind of catastrophic flooding that Category 5 Cyclone Gonu of 2007 brought to Oman. Gonu killed 50 people and did $4.2 billion in damage. Phet's heaviest rains will be confined to a relatively sparsely populated region of Oman's coast. Rainfall amounts in excess of 6 inches in 18 hours (Figure 3) can be expected along Oman's coast today, which will likely cause extreme flooding.

After Phet's encounter with Oman, the storm will probably be at tropical storm strength when it makes its second landfall in Pakistan. Heavy rains from Phet will be the major danger for Pakistan, and serious flooding can be expected over southern Pakistan.


Figure 3. Forecast rain amounts for the 18-hour period ending at 2am EDT June 3, 2010. Image credit: NOAA/NESDIS.

Oil spill update
Onshore winds out of the south, southwest, or west are expected to blow over the northern Gulf of Mexico over most of the next week, resulting increased threats of oil to Alabama, Mississippi, and the Florida Panhandle, according to the latest trajectory forecasts from the State of Louisiana. The latest ocean current forecasts from the NOAA HYCOM model show that these winds will generate a 0.5 - 1 mph current flowing from west to east along the Florida Panhandle coast Sunday and Monday. If this current develops as predicted, it will be capable of bringing light amounts of oil as far east as Fort Walton Beach, Florida, by Monday. If you spot oil, send in your report to http://www.gulfcoastspill.com/, whose mission is to help the Gulf Coast recovery by creating a daily record of the oil spill.

Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
My post Wednesday with answers to some of the common questions I get about the spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

I'll be back Friday with an analysis of the new TSR hurricane forecast and a new forecast by a promising Florida State University model.

Jeff Masters

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Hydrate icing occurs at deep water pressure and not close to the surface where instead hydrate become gas and does not crystalize. Methane hydrate deposits under the Deepwater Horizon were found to be the largest ever encountered in a drilling operation. There have been repeated failures of PB drill equipment during their drill operations because of the unusually high releases of hydrate they encountered. If the pipe above the cap becomes hopelessly clogged, it might be disconnected by the ROV to keep back pressure from blowing the pipe within the BOP below.
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Quoting AstroHurricane001:


The blob north of the Virgins should be labelled an invest.

Hi Astro...it's called a surface trough right now..."THIS SURFACE TROUGH IS EXPECTED TO SLOWLY MOVE EASTWARD AS THE CONVECTION WEAKENS OVER THE NEXT 24 HOURS."
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Waterwith, yes, there were 2 quakes in the Gulf in 2006 - one in February, and a stronger one in September that year, In fact, in the Sept. 11 National Geographic online info, there were two linked articles. One discussed the earthquakes, and in this article it mentioned that it "had not affected" the deep water oil drilling project. Click on that link, and you will be taken to the other article, same date. In it, BP boasts of just how deeply they are drilling and how much oil there is at that level. It is defnitely the same well that is leaking enormously here. So which came first, the quake or the drilling? My money is on the drilling, because they cut through a layer of rock thousands of feet down.
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Here's Phet. It's got an area of moisture ahead of it:



Looks like it's not going to encounter any shear higher than 20-25 kt.
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1764 thanks Patrap!
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1825. gator23
Quoting Clearwater1:
Does anyone know if BP could file bankruptcy walk away from this? Is that possible? Anyone in the legal profession know the answer?


1)their share holders would have to approve their chapter 11 request and that isn't likely
2)A court would have to approve a chapter 11 hearing and they wont touch it
3)they are still making money hand over fist
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Quoting gator23:

I understand why people are focused on the oil spill as it involves all of us. That said I dont entirely disagree with his sentiment. It seems the same folks who complain when we talk about politics or GW because it is "off topic" are also off topic themselves about the Oil Gusher.

So wrong ... this isnt opinion .. this isnt debatable. This is a disaster of epic proportions and demands the attention of any media outlets, not excluding a "weather" blog. I do not think the Doc would have any problems with the majority of what is being said (though I dont know if he approves of us setting Mr "I want my life back" adrift in the oil slick .... but oh well)
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Quoting btwntx08:
ok yes im kidding im like this cause it sometimes gives me headaches


We all get headaches from time to time. It's all a part of too much information:

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Quoting Acemmett90:


his new home going be a 4 by 4 cell in a federal penitentury, oh yah make sure he drops the soap


They can screw him just like he screwed our gulf!
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My Cheasepeak Bay is already on the down slope, and an "Isabel" situation (not even landfalling here, just flooding us) would be devestating for our waters and DC's waters as well...
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1819. KEEPEROFTHEGATE (Mod)
Quoting MrstormX:
Tampa was banned?
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1817. gator23
Quoting CaneWarning:


The oil spill is on topic, Dr. Masters mentioned it in his post.


Excellent point. But hr regularly references politics and GW and we can still be banned for that.
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THE ATLANTIC OCEAN...
BROAD UPPER LEVEL ANTI-CYCLONIC FLOW COVERS THE FAR EASTERN AND WESTERN ATLANTIC AREA OF DISCUSSION THIS EVENING. HOWEVER...AN UPPER LEVEL LONGWAVE IS OVER THE CENTRAL ATLANTIC, RIGHT IN BETWEEN THESE TWO AREAS OF ANTI-CYCLONIC FLOW, SUPPORTING AN AREA OF WEAK SURFACE TROUGHINESS FROM 20N TO 30N BETWEEN 34W AND 48W. WEAK TO ISOLATED MODERATE CONVECTION IS WITHIN THIS REGION.
COMPUTER MODELS SHOW THIS AREA OF CONVECTION WILL DIMINISH OVER THE NEXT 24 TO 36 HOURS. A SURFACE TROUGH IS ANALYZED OVER THE WESTERN ATLANTIC ALONG 25N68W 23N72W 20N74W. MODERATE TO ISOLATED MODERATE CONVECTION IS FOUND EAST OF THE SURFACE TROUGH...FROM 21N TO 26N BETWEEN 65W AND 71W. WEAK UPPER LEVEL DIVERGENCE EAST OF THE BAHAMAS IS FURTHER SUPPORTING THE CONVECTION IN THIS REGION. THIS SURFACE TROUGH IS EXPECTED TO SLOWLY MOVE EASTWARD AS THE CONVECTION WEAKENS OVER THE NEXT 24 HOURS. NO SIGNIFICANT WEATHER IS OCCURRING OR EXPECTED TO DEVELOP ELSEWHERE ACROSS THE ATLANTIC.
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1815. leo305
There is a huge amount of oil spewing down there.. looks to me like it's far more than it was originally spewing before the cuts..
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Does anyone know if BP could file bankruptcy walk away from this? Is that possible? Anyone in the legal profession know the answer?
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Pottery - YGM
Quoting pottery:

Not sure that the flow has doubled. 25% more was expected. Double that for error (or PR), and lets say 50% more.
Still a crazy amount....
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Quoting Chicklit:


The blob north of the Virgins should be labelled an invest.
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Quoting KoritheMan:


Congrats for displaying a complete lack of understanding of the situation...


That was to btwntx08

Because this needs to be said twice. He might miss it on page 36. No way I'm letting that happen.
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Quoting gator23:

I understand why people are focused on the oil spill as it involves all of us. That said I dont entirely disagree with his sentiment. It seems the same folks who complain when we talk about politics or GW because it is "off topic" are also off topic themselves about the Oil Gusher.


The oil spill is on topic, Dr. Masters mentioned it in his post.
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1809. Ossqss
Quoting btwntx08:

well u cant understand but i can this oil stuff is giving me a headache


We can always change the channel
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In normal drilling operations don't they normally pump seawater or something into the well to replace the oil?
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so, this oil gets into the Gulf Stream, like they're predicting, and then we have landfalling Tropical Storms or Hurricanes along the Gulf Coast and The East Coast and everyone is screwed from Texas to Maine.

Brilliant.

BP = BIG PR*CKS!!!

sorry... rage chokes sometimes.
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Quoting CaneWarning:


I don't have an answer to that.


Ok I was just wondering if there was a reason I wasn't aware of so I didn't do it. Thanks
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First I am from the mining industry so my tech knowledge on this is better than most...but then again a little bit of knowledge is dangerous...especially to me..

The current cap for the BOP is different than previous fixtures ("top hat" etc) as it has lines to pump the equivalent of a "de-icer" into the capture area of the cap. The hydrate buid up Patrap discussed is indeed a possible reason for the current blow-by we are seeing. That said, the cap has been under suction since they began lowering it today. It is key to lowering it into place and guiding it as without that suction the cap would bounce side to side and be hard to control. There does seem to be a problem of flow rate which could be due to hydrate "icing" in the tube farther up the suction pipe. The "de-icing" capability has difficulty handing hydrate ice build-up if it occurs too far away from their nozzle in the cap.
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Tampa was banned?
Member Since: May 27, 2009 Posts: 0 Comments: 4454
I think TampaSpin was banned because he linked to his own website?
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1799. gator23
Quoting SouthALWX:

He had best be or an angry WU mob is in his future, for sure.

I understand why people are focused on the oil spill as it involves all of us. That said I dont entirely disagree with his sentiment. It seems the same folks who complain when we talk about politics or GW because it is "off topic" are also off topic themselves about the Oil Gusher.
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1798. JLPR2
After watching innocent animals covered with oil I got the urge to trow a bowl of oil over the people responsible of this ¬¬

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Quoting Patrap:
I'd like to dip The BP Head Dog in the Marsh slowly..from a Cane Pole..,like the worm he is.


The Atlantic Current can take him back to England the Long way..via the Loop.


Pat, If this spill keeps up he can ride back on the oil he brought up to the surface.
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Quoting champagnedrmz:
Can I ask why Tampa would be banned for posting links to the oil spill when it is a subject in Doc's blog?


I don't have an answer to that.
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Quoting btwntx08:

well u cant understand but i can this oil stuff is giving me a headache


Congrats for displaying a complete lack of understanding of the situation...
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1793. IKE
Quoting champagnedrmz:
Can I ask why Tampa would be banned for posting links to the oil spill when it is a subject in Doc's blog?


No reason to be banned from what he was posting unless I missed something.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
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1791. Patrap
Quoting IKE:


You mean the idiot that said..."I want my life back"?


Dat be da one my Good Neighbor to my East
Member Since: July 3, 2005 Posts: 433 Comments: 132798
1789. IKE
Quoting help4u:
Joe Biden on Charlie Rose show said BP has done the best they could possibly do!LOL!


Well you know what Joe, that ain't good enough.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting btwntx08:

well u cant understand but i can this oil stuff is giving me a headache


It's giving us all a headache but it's the only pressing matter right now. What are we to discuss with the tropics? There's nothing happening there.
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1786. Patrap
Quoting mikatnight:
Hi Pat (#1740) -

It seems to me that no President since Harry Truman has had so much on his plate.


Well.. another Plane , another President,another Visit,...


I dont even Look Up at the Damn Thing anymore since Sept 2 ,2005.
Member Since: July 3, 2005 Posts: 433 Comments: 132798
1785. IKE
Quoting Patrap:
I'd like to dip The BP Head Dog in the Marsh slowly..from a Cane Pole..,like the worm he is.


The Atlantic Current can take him back to England the Long way..via the Loop.




You mean the idiot that said..."I want my life back"?
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Can I ask why Tampa would be banned for posting links to the oil spill when it is a subject in Doc's blog?
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Quoting sarahjola:
do you think that a crack or something will force an earthquake? i can see why something like that could happen but i know nothing about earthquakes and that is a thought that scares the hell out of me. could you elaborate? thanks in advance


how to answer this. i know that we have fault lines everywhere. i know that an earthquake occurred in the gulf in 2006, which is a rare event and a fault line was found. there is no place on this earth that needs any extra push in order to have serious consequences, especially in the ocean with tons of pressure put on it.
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Quoting Patrap:
I'd like to dip The BP Head Dog in the Marsh slowly..from a Cane Pole..,like the worm he is.


The Atlantic Current can take him back to England the Long way..via the Loop.



Nah the loop is breaking off . he can just circulate in the eddy along with all of his oil for a while.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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