CSU predicts highly active hurricane season; Cyclone Phet approaching Oman

By: Dr. Jeff Masters , 14:00 GMT le 03 juin 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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1730. IKE
Quoting Nolehead:
1666. IKE 2:03 AM GMT on June 04, 2010
Anderson Cooper is hammering BP as well.



he's been doing that from the gitgo....


He said BP should have a spokesman explaining what is going on, like NASA does with the space shuttle flights. I agree.

BP is not going to survive this.
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1729. pottery
Quoting DestinJeff:
things looked so much better pre-cap

Well thats because the flow before the cap was all nice and contained in one stream. There is no more oil now than before. It looks a whole lot worse though.
Member Since: 24 octobre 2005 Posts: 0 Comments: 24373
Quoting btwntx08:
ok lets go back tropics here

okay:
Nothing going on for the foreseeable future.
Now, back to what matters, the oil.
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Quoting champagnedrmz:
Did anyone see the public service announcement this evening around 7 from BP on channel 25 here in Port Saint Lucie but it is an ABC channel? How pathetic they are!


It played everywhere I think.
Member Since: 26 avril 2009 Posts: 3 Comments: 3667
1725. Ossqss
Quoting pottery:

I was thinking that. Its going to take a while before the "flow" up the pipe is moving along. There is a mile of static fluids in the pipe.


Ya gotta remove the cork. Oh, you know that :)
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Did anyone see the public service announcement this evening around 7 from BP on channel 25 here in Port Saint Lucie but it is an ABC channel? How pathetic they are!
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Well I'm out, I might come back later.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
1666. IKE 2:03 AM GMT on June 04, 2010
Anderson Cooper is hammering BP as well.



he's been doing that from the gitgo....
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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


The oil was being pump out of the earth anyway, and it didn't cause an earthquake, so I doubt it would in this case. But, if one happens, near by, I'm blaming BP, just because.
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Kudos to that
Member Since: 27 mai 2009 Posts: 0 Comments: 4438
Quoting louisianaboy444:


And 343 Firefighters....my Father has been on the job for 28 years their instinct is to go! Ask questions and have fears later...may they all rest in peace
Amen.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
Quoting louisianaboy444:


And 343 Firefighters....my Father has been on the job for 28 years their instinct is to go! Ask questions and have fears later...may they all rest in peace
amen!
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Quoting pottery:

I was thinking that. Its going to take a while before the "flow" up the pipe is moving along. There is a mile of static fluids in the pipe.


Yes but the flow is doubled, im sure there is some going up the pipe but at most half the oil is. And if the flow is doubled, we are no better than when we started.
Member Since: 27 mai 2009 Posts: 0 Comments: 4438
Quoting Levi32:


No, you cannot compare the loss of unintelligent animals to the deaths of 2995 human beings.


And 343 Firefighters....my Father has been on the job for 28 years their instinct is to go! Ask questions and have fears later...may they all rest in peace
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BP = Breaking Point.
Member Since: Posts: Comments:
Quoting Levi32:


No, you cannot compare the loss of non-sentient animals to the deaths of 2995 human beings.
Yeah I agree, I think he may of gone overboard. I think the real number is 2976, I don't think you could call the terrorists "human beings".
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
1708. pottery
Quoting JamesSA:
The oil has to push a mile of seawater out the top of the pipe first before it can begin flowing properly.

I was thinking that. Its going to take a while before the "flow" up the pipe is moving along. There is a mile of static fluids in the pipe.
Member Since: 24 octobre 2005 Posts: 0 Comments: 24373
Quoting WaterWitch11:
1654. CaneWarning 1:59 AM GMT on June 04, 2010
This may be a stupid question, but is it possible that this could cause an earthquake somewhere? I would think losing that much oil this quickly could cause a problem. Bad question I know.

my opinion and probably mine alone but i having been watching almost waiting for an earthquake to occur in the area.
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
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Quoting JamesSA:
The oil has to push a mile of seawater out the top of the pipe first before it can begin flowing properly.

This is my thinking also, isnt going to happin right away. fingers crossed many times!!!!
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Quoting KEEPEROFTHEGATE:
thats a sin man a real sin
(sigh). Facepalm.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
1703. Levi32
Quoting mcluvincane:
My God this is worse than 911


No, you cannot compare the loss of unintelligent animals to the deaths of 2995 human beings.
Member Since: 24 novembre 2005 Posts: 635 Comments: 26652
damn i can't even look at the pictures of the animals without crying this is so bad. i just wish that more was done in the beginning. people screaming for more to be done and no one listened.
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1701. reveler
BP=Butt Plug
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1699. KEEPEROFTHEGATE (Mod)
Quoting mikatnight:


No words...
thats a sin man a real sin
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Quoting Acemmett90:


canes you know its heading towerds us if it gets into the loop thats going ruin of summer
Depressing ain't it? Well let's pray for the best.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
My God this is worse than 911
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Quoting JamesSA:
The oil has to push a mile of seawater out the top of the pipe first before it can begin flowing properly.


Shouldn't take long at that pressure.
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BP = Big Problem
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
I would say we have a frozen clogged pipe...JMO
Member Since: 2 septembre 2007 Posts: 178 Comments: 20443
1691. JamesSA
The oil has to push a mile of seawater out the top of the pipe first before it can begin flowing properly.
Member Since: 17 août 2009 Posts: 0 Comments: 579
Quoting IKE:


Flood lights from behind.


Ok that makes a lot more sense. I couldn't imagine there being fire there really.
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Updated daily
June 3, 2010


Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
This is awful... im very depressed right now
Member Since: 27 mai 2009 Posts: 0 Comments: 4438
Quoting WaterWitch11:
1654. CaneWarning 1:59 AM GMT on June 04, 2010
This may be a stupid question, but is it possible that this could cause an earthquake somewhere? I would think losing that much oil this quickly could cause a problem. Bad question I know.

my opinion and probably mine alone but i having been watching almost waiting for an earthquake to occur in the area.


I'm thinking the same thing.
Member Since: 26 avril 2009 Posts: 3 Comments: 3667
1682. IKE
Quoting champagnedrmz:
Is that fire coming up from the top? I know don't yell at me?


Flood lights from behind.
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Quoting AllStar17:
Clearly some kind of rotation near 10 N 50 W


Saw that also
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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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