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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this just in from walton co. sheriff:

DEEPWATER HORIZON OIL SPILL UPDATE



The Emergency Operations Center remains at a level 3 and we are monitoring the situation in our neighboring counties, states and the gulf.

Recent reports from DEP indicate that a FWC reconnaissance plane spotted oil sheen approximately 6 miles from the Navarre Pier. It is still uncertain if or when oil could reach our beaches.

We are ready to initiate our Coastal Dune Lake Protection Plan, awaiting DEP permit. The 1st stage of the plan is to pre-stage sand (sand will be brought in NOT scrapped from our beaches) close to the lakes which will be used to close the lakes if necessary.


Southwest winds are expected to continue through Sunday with speeds of 10-15 knots. Trajectories show a northeastward movement of oil over the next 3 days, threatening the shorelines of Alabama and possibly the western Florida Panhandle. Forecasted increases in seas and a 50-80% chance of showers and thunderstorms through Friday may hamper surface oil recovery operations. West winds are forecast for early next week, though a rare late season cold front may produce offshore winds as early as next Wednesday.


Oil-water mix recovered: approximately 14.8 million gallons.
There is currently no plan to use dispersants in Florida waters.


If oil is sighted on Florida’s coastline, report it to the State Warning Point at 1-877-2-save-fl (1-877-272-8335) or by dialing #DEP from most cell phones.


Member Since: Posts: Comments:
Quoting auburn:
Hope this dont get me banned..but with all thats going on we all need a laugh...so here goes!!!

" Here's the problem," Doc tells a first-time dad. "This baby badley needs a diaper change."
Looking confused, the man replies, "But the package says its good for eight to ten pounds!"


I've always liked you, Auburn...LOL
Member Since: Posts: Comments:
879. auburn (Mod)
Hope this dont get me banned..but with all thats going on we all need a laugh...so here goes!!!

" Here's the problem," Doc tells a first-time dad. "This baby badley needs a diaper change."
Looking confused, the man replies, "But the package says its good for eight to ten pounds!"
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:
are you ok or are ya a little nuts


RItaEvac? He's a lotta nuts
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OIL SPILL LIVE VIDEO FEEDS

You all gotta see this....very jagged edge on the cut off.....oH BOY
Member Since: September 2, 2007 Posts: 179 Comments: 20450
876. xcool
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Every thing in the Atlantic looks pretty quiet right now, but, soon things are going to get really busy.
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Quoting StormW:


Right now, it would have to sneak under the TUTT axis that it's approaching.


Interesting looking feature for this time of the year but perhaps a clear sign of the rising ITCZ and of how a viable CV wave train might sneak up on us headed towards the Lesser Antilles a little earlier than usual.....
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Quoting RitaEvac:
looking out window, it has become breezy.

Breaking News: Tropical Storm warning in effect for Texas Coast. Massive swirl over Texas has become better organized. Circulation is becoming tighter and bands are beginning to form around the circulation. Later tonight rain shield should shrink closer and tighter around the circulation center with very heavy rains and flooding near and east of center. Winds will also increase and seas will become rough.


FALSE FALSE!!! Don't post bogus stuff!
Member Since: September 2, 2007 Posts: 179 Comments: 20450
872. xcool


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Quoting WPBHurricane05:
Looks like coastal Palm Beach will miss the fun stuff today. Can hear plenty of thunder and we did get a little rain.



Jupiter getting hammered right now.
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OIL SPILL LIVE VIDEO FEEDS
Member Since: September 2, 2007 Posts: 179 Comments: 20450
Quoting RitaEvac:
looking out window, it has become breezy.

Breaking News: Tropical Storm warning in effect for Texas Coast. Massive swirl over Texas has become better organized. Circulation is becoming tighter and bands are beginning to form around the circulation. Later tonight rain shield should shrink closer and tighter around the circulation center with very heavy rains and flooding near and east of center. Winds will also increase and seas will become rough.
are you ok or are ya a little nuts
Member Since: July 15, 2006 Posts: 192 Comments: 59095
Palm Beach and Broward Co. looks pretty stormy.Link
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looking out window, it has become breezy.

Breaking News: Tropical Storm warning in effect for Texas Coast. Massive swirl over Texas has become better organized. Circulation is becoming tighter and bands are beginning to form around the circulation. Later tonight rain shield should shrink closer and tighter around the circulation center with very heavy rains and flooding near and east of center. Winds will also increase and seas will become rough.
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our worst fears are coming true,really pisses me off:(
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http://radar.weather.gov/radar.php?rid=HGX&product=NCR&overlay=11101111&loop=yes
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863. xcool
insurance companies will not pay...if hurricane hit.wt;;;;
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Looks like coastal Palm Beach will miss the fun stuff today. Can hear plenty of thunder and we did get a little rain.

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Quoting Zhills:
I'm in Plant City. We got three rain drops and the sun in back out. So much for the rain.
I feel ya, meanwhile just 15 miles to my east has over 5' in two days.
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858. xcool
TampaSpin .hey
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What's going on over Houston right now??
Looks like a eye?
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Quoting MississippiWx:


Not enough time over water, if it moved over water at all. People have to consider that this system is not warm-core and would take several days over a warm body of water to turn warm core. This disturbance won't have that opportunity.


Warm Core or Cold Core which it is! It makes no difference as its still gonna blow the OIL onshore in the Panhandle and into the Shores of Louisiana, Mississippi, and Alabama too. Cold core, Warm core makes no difference the stuff is now coming.

Nice Convergence also at 10N50W thats needs monitoring now.




Member Since: September 2, 2007 Posts: 179 Comments: 20450
I'm in Plant City. We got three rain drops and the sun in back out. So much for the rain.
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Quoting Jeff9641:
Storms have just down right exploded here north of Orlando. Reports of small hail all over the place I just had a 50 mph wind gust. Also, Very strong storms moving quickly toward Tampa Bay in several hours.


Had some real nasty ones in Melbourne as well!
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853. xcool
7 People in Weather Chat!
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Quoting Funkadelic:
All in all pretty quiet in the Atlantic. This season is going to be off and running towards the ladder parts of June, up until the last day of the season. There is so much warm water and energy in the Atlantic that something is bound to burst. The next MJO pulse should officially get the action started. Just bought all my hurricane stuff today, hope everyone is prepared.


I concur. Conditions just aren't ripe yet, but around they end of the month when they are, the season will truly get going and we're going to wish we still had another month or so.
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heh
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting MrstormX:
It appears to me the Tropical Wave associated with the ITCZ is trying to break free,


How about the TropicalWave associated with the shower curtain? (Sorry. I tried resisting and just couldn't help myself.)
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50w 10n does look interesting I think something besides a purple hippo is closing in on Pottery.
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Quoting StormW:


Yea...steering should take it just north of the coast.


Could a TC form potentially, or is that highly unlikley.
Member Since: May 27, 2009 Posts: 0 Comments: 4454
Quoting StormW:


Yea...steering should take it just north of the coast.


This wave could spark something in the SW Caribbean in a few days
Member Since: March 10, 2010 Posts: 1 Comments: 8091
Quoting Jeff9641:


The blob moving quickly from the Central Gulf. Lots of lightning noted with this cluster. THis is the remaining squall that went through Texas.


Do you have a radar on that?
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting Jeff9641:


The blob moving quickly from the Central Gulf. Lots of lightning noted with this cluster. THis is the remaining squall that went through Texas.


I am seeing outflow boundaries coming from that line, not sure there will be much left of it by the time it gets to the West coast of Florida
Member Since: March 10, 2010 Posts: 1 Comments: 8091
It appears to me the Tropical Wave associated with the ITCZ is trying to break free, or at least the convection from it is starting to shift NorthWest.
Member Since: May 27, 2009 Posts: 0 Comments: 4454
Afternoon StormW, how's the Mustang runnin'?
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Quoting CycloneOz:


I guess I will.

/me looks at calendar and scratches head.


or just wait til I see you which will likely be relatively soon...
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Quoting Jeff9641:
Storms have just down right exploded here north of Orlando. Reports of small hail all over the place I just had a 50 mph wind gust. Also, Very strong storms moving quickly toward Tampa Bay in several hours.


Not sure about that.. all radar shows rain blowing to the ENE...
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832. xcool


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831. xcool
StormW :)
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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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