CSU predicts highly active hurricane season; Cyclone Phet approaching Oman

By: Dr. Jeff Masters , 2:00 PM GMT en Junio 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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Quoting reid221:
Does anyone know of information available on how the evaporated oil and dispersant is integrating with the atmosphere? Can compounds be carried in rain? In what concentrations? Who monitors this - how and where?


I tell this: I was in Westwego. LA during a rain shower and there was an oily rainbow sheen on my windshield.
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Quoting stillwaiting:
hows about alberto,it formed at first along mex. coastline???


No, the disturbance that spawned Alberto did not come from an MCS over land.
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hows about alberto,it formed at first along mex. coastline???
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Is that wave starting to lift out of the ITCZ.
Member Since: Mayo 27, 2009 Posts: 0 Comments: 4438
I just added 1 more live feed......refresh your page to get it! LIve feeds from the OIL Gusher

Looks like the CAP is on the last live feed!
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573. pottery 11:37 AM PDT on June 03, 2010
Did I hear someboddy say "SPILL BABY, SPILL" ??
Or did I misunderhear that?


no, that was "Grill, Baby, GRILL!!!!"....as in grill my lunch!
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Quoting Jeff9641:


I thought it did. What about Cluadette from last year.?


Everything about Claudette took place over water.
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Did I hear someboddy say "SPILL BABY, SPILL" ??
Or did I misunderhear that?
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Quoting hurricanejunky:


Is there a way to stop clicking the play button on your avatar?


LOL. I thought it was appropriate given the political ranting that was going on earlier. If it's really that obtrusive, perhaps I'll shelve it until the next round of rants.
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Something in the 90s come offshore from LA and MISS. I remember seeing storms blowing up everyday and moving offshore and it eventually spun up a low pressure becoming a tropical storm
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2010060300z ECMWF RUN NAO Values
NAO value for forecast hour 000: -49.3112488
NAO value for forecast hour 024: -29.9639282
NAO value for forecast hour 048: -4.7077179
NAO value for forecast hour 072: 25.3341331
NAO value for forecast hour 096: 30.9347382
NAO value for forecast hour 120: 15.310482
NAO value for forecast hour 144: -33.480629
NAO value for forecast hour 168: -59.340229
NAO value for forecast hour 192: -123.563507
NAO value for forecast hour 216: -176.906708
NAO value for forecast hour 240: -117.006409
NAO value for Day 1-5: 7.38154125
NAO value for Day 6-10: -102.059494

The ECMWF is showing a stronger negative again in mid June.

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Quoting pottery:
What we are seeing with the cut Riser--- that does not look like it was cut with the shears, looks more like a wire-cut.
Not seeing a lot of deformation there, which I would expect with the shears? Strange!
The straight looking cut is from the wire saw. They should just clamp it back on and let it finish.
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Quoting Levi32:


Is that what I keep thinking of? Let me check.


No....didn't come from MCS.
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Does anyone know of information available on how the evaporated oil and dispersant is integrating with the atmosphere? Can compounds be carried in rain? In what concentrations? Who monitors this - how and where?
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Quoting Jeff9641:


Humberto I believe is the best illustration.


Is that what I keep thinking of? Let me check.
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Quoting MrstormX:
Danny of '97 and Beryl of '88 look like sure possabilites.


Danny's formation originated and stayed over water.

Beryl is possible...was over land looking like this 2 days before it was named.



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What we are seeing with the cut Riser--- that does not look like it was cut with the shears, looks more like a wire-cut.
Not seeing a lot of deformation there, which I would expect with the shears? Strange!
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Plug the leak!, "I cannot do that Dave"

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some of these storms in South Florida are just popping up everywhere. The one I am dealing with just west of Margate has hail in it, and basically popped off of nothing.
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post #551

OMG!!!! WTH is with the big graphics today???!!!!
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Now, what does all of this underwater work remind me of...

Hmmm




No, still not coming to me...
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556. IKE
They had a report on CNN this morning about the difficulty of doing what they're doing in the GOM. Think they were saying it takes 3 people to do what all they're doing.
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Danny of '97 and Beryl of '88 look like sure possabilites.
Member Since: Mayo 27, 2009 Posts: 0 Comments: 4438
I'm guessing it'll get clogged w/crystal's that will form due to the high pressure enviornment,I doubt the methaine they pump in w/work,but I sure hope it does work!!! and about the line of wx moving across GOM,seriously doubt it w/make it to fl's west coast,we'll get some storms tonight along the coastline but from the seabreeze or land breeze overnight....
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553. Skyepony (Mod)
Kermit is out on a mission named Deepwater05, flying over the gulf current. Looks like back in forth from the south end to toward the north. They are playing in that storm..25kts highest at the surface so far.

Just got a Thunderstorm warning here..
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Quoting IKE:
They trying to cut off a bolt on the BOP?

some kind of stubborn bracket....
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Quoting Hurricanes101:
Or Fay in 2002?


Nope, upper low backing away from a tropical wave......BEAUTIFUL example of that particular situation though. Love it.

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The saw has gone to the Left. Enough of that right-wing stuff.
Now we talkin'....

LOL
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549. IKE
Quoting JamesSA:
No, just that flattened out piece of pipe.


Okay. Looks like they're trying to get that piece off and out of the way.
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thx to whomever replied to my question.. i appreciated..
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GOES-12 Low Cloud Product
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Levi look up Tropical Storm Beryl of 1988 it might be one similiar to this, but idk.
Member Since: Mayo 27, 2009 Posts: 0 Comments: 4438
Quoting IKE:
They trying to cut off a bolt on the BOP?
No, just that flattened out piece of pipe.
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Quoting Hurricanes101:


How about Edouard in 2008?


No just a tail-end of a front.
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Or Fay in 2002?

It developed from an upper level trough that moved off of Texas
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Quoting Hurricanes101:


How about Edouard in 2008?


Maybe but I think it developed a low pressure offshore, where as this one already has it.
Member Since: Mayo 27, 2009 Posts: 0 Comments: 4438
yes,heat lightning is lightning far off in the distance...
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Quoting Levi32:


Stacked low means the upper low, mid-level low, and surface low are all stacked right on top of each other. That's what we mean by "vertically stacked".

Vort lobe is just referring to some sort of vort max that rotated around the low, sort of like a small shortwave trough.


Ah ok. Thank you. :)
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Quoting hurricanejunky:


Is there a way to stop clicking the play button on your avatar?


Yes,,use the HIDE feature,or the ignore as I did.
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Im not sure but maybe Hurricane Danny of 1997? Haven't had a chance to really look though.
Member Since: Mayo 27, 2009 Posts: 0 Comments: 4438
Quoting sirmaelstrom:


OK, Thanks. I can stop clicking the "play" button then.


Is there a way to stop clicking the play button on your avatar?
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Quoting FLPandhandleJG:
Hey everyone.. I'm going to ask a stupid question but here it goes.. Can heat lightning strike anything or is just flashes of lightning in a sky of a nearby storm or a remnants of a storm? and does it usually occur in Florida??

Because I saw very nice heat lightning last night then like 30 or so minutes later i heard some thunder.. But it was very entertaining for awhile..
I believe heat lightning are distant storms.
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Quoting Levi32:


Same here....I keep thinking I should be able to pull up an example.


That D storm over Oklahoma, but it was tropical to begin with.
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Quoting FLPandhandleJG:
Hey everyone.. I'm going to ask a stupid question but here it goes.. Can heat lightning strike anything or is just flashes of lightning in a sky of a nearby storm or a remnants of a storm? and does it usually occur in Florida??

Because I saw very nice heat lightning last night then like 30 or so minutes later i heard some thunder.. But it was very entertaining for awhile..
"Heat lightning" is actually no different than regular lightning, it is just distinguished because it occurs within the cloud (or on the far side of a cloud from the observer).
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Quoting Levi32:


Same here....I keep thinking I should be able to pull up an example.


How about Edouard in 2008?
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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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