First Category 5 storm of the year is Choi-Wan

By: Dr. Jeff Masters , 1:38 PM GMT on September 16, 2009

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The remains of Hurricane Fred continue to generate sporadic bursts of heavy thunderstorm activity over the middle Atlantic Ocean. These thunderstorms were generating winds up to 30 mph, according to this morning's QuikSCAT pass. However, QuikSCAT also showed that the remains no longer have a surface circulation. Water vapor satellite loops show that ex-Fred has moved beneath an upper-level low pressure system. This low features dry air on all sides, and this dry air will interfere with any redevelopment of Fred. While wind shear is now moderate, 10 - 15 knots, and is expected to remain in the moderate range for the next five days, the presence of so much dry air will require at least three days for the remains of Fred to overcome and regenerate a surface circulation. Only the HWRF model redevelops Fred, predicting it will develop on Sunday as it approaches the Bahama Islands. NHC is giving ex-Fred a low (less than 30% chance) of developing into a tropical depression by Friday. Fred's remains will be near the Bahamas on Sunday, and near Florida on Monday night. It is possible that a strong trough of low pressure expected to develop over the eastern U.S. early next week will turn Fred's remains northwards into South Carolina/North Carolina on Monday/Tuesday.

This morning's QuikSCAT pass shows a surface circulation near 13N 32, with a small region of heavy thunderstorms to the north. This region is about 450 miles west of the Cape Verdes Islands, and is headed west at about 10 mph. Satellite imagery shows a decrease in the amount of heavy thunderstorm activity this morning, and high wind shear of 20 knots is interfering with development. A band of high wind shear lies just to the north of the disturbance, and will continue to interfere with the system's development over the next three days. NHC is giving the system a low (less than 30% chance) of developing into a tropical depression by Friday.

The GFS model is predicting development of a new tropical wave coming off the coast of Africa early next week.


Figure 1. The remains of Hurricane Fred (left) keep on chugging across the Atlantic. A tropical wave is 450 miles west of the Cape Verdes Islands (right). The thunderstorms of the Inter-Tropical Convergence Zone (ITCZ) are far to the south, off the coast of Africa.

Super Typhoon Choi-Wan hits Category 5 strength
This year's first Category 5 tropical cyclone is Super Typhoon Choi-Wan, which intensified into a Category 5 storm with 160 mph sustained winds yesterday afternoon. Choi-Wan is over the open ocean south of Japan, and is not expected to impact any land areas. It is unusual to have to the globe's first Category 5 storm form this late in the year. Indeed, global tropical cyclone activity as measured by the ACE index, which measures destructive potential, has been near historic lows over the past two years. Only one Category 5 storm was recorded in 2008--Super Typhoon Jangmi, which attained winds of 165 mph at 06 GMT on September 27, as it approached the north coast of Taiwan. The last time so few Category 5 storms were recorded globally was in 1974, when there were none.

We got a rare treat yesterday when the Cloudsat satellite caught a perfect cross section through Choi-Wan when it was a Category 4 super-typhoon with 150 mph winds (Figure 2). The CloudSat satellite, launched in 2006, carries the first satellite-based millimeter wavelength cloud radar. It is the world's most sensitive cloud-profiling radar, more than 1000 times more sensitive than current weather radars. It collects data about the vertical structure of clouds, including the quantities of liquid water and ice, and how clouds affect the amount of sunlight and terrestrial radiation that passes through the atmosphere. The satellite has a narrow field of view, so can image only a small portion of the planet each day. About once per year, CloudSat happens to slice through the eye of an Atlantic hurricane. This happened last month, when Cloudsat caught a remarkable view of Hurricane Bill.


Figure 2. Top: conventional visible satellite image of Super Typhoon Choi-Wan at 3:57 UTC Tuesday, 9/15/09 from Japan's MTSAT. Bottom: cross section through Choi-Wan's eye taken at the same time, from the CloudSat cloud radar instrument. The CloudSat pass occurs along the red line in the top image. The CloudSat pass runs from south (left side of CloudSat image) to north (right side of CloudSat image). At the time of the image, Choi-Wan was strengthening into a Category 4 Super Typhoon (150 mph winds, 928 mb pressure), and reached Category 5 strength fourteen hours after this image was taken. In the CloudSat image, one can see 6+ isolated towers, marking the positions of spiral bands on the south side of the center. The eye is remarkably well-defined, with symmetric "hot towers" extending up to 55,000 feet, sloping outward with height. The thin solid grey line at 5 km marks the 0°C temperature line. Ice particles falling inside the hurricane melt at an altitude just below the 0°C line, creating a "bright band" of orange echoes throughout most of the hurricane. This is one a few inner eye images CloudSat has captured of an Category 4/5 tropical cyclone. Image credit: NASA/Colorado State University/Navy Research Lab, Monterey.

Twenty years ago today
On September 16, 1989, Hurricane Hugo weakened slightly as it underwent an eyewall replacement cycle. The tight inner eyewall that we had flown through the previous day had contracted to the point where it became unstable and collapsed. A new eyewall formed out of an outer spiral band, and Hugo's highest winds dropped to 140 mph--Category 4 strength. As this was occurring, the storm began a more northwesterly path and slowed down, in response to a region of low pressure north of Puerto Rico. By midnight, Hugo was only an hour away from its first encounter with land--the Lesser Antilles island of Guadeloupe.

Back on Barbados, our one undamaged P-3 Orion Hurricane Hunter aircraft flew a mission into Hugo, while the crew of the damaged aircraft remained on the ground. Our plane was grounded until a team of experts from the mainland could fly out and perform a detailed x-ray analysis of the wings to determine if the high g-forces we endured had caused structural damage. This might take a week, so the plan was to fly us back to Miami on a commercial jet. However, Hugo had forced the cancellation of virtually every commercial flight in the eastern Caribbean that day, so we were stuck on the island. Most of us spent a frustrated day touring the island on rented mopeds, getting a look at Hugo from the ground. We got thoroughly drenched by one of Hugo's outermost spiral bands, but the hurricane was too far away to bring any winds more than 20 mph to the island.

That night, our already jangled nerves got a new jolt--a tropical depression had formed due east of Barbados, and was headed right for us. In two days time, it seemed likely that Tropical Storm Iris would be paying us a visit.


Figure 3. AVHRR visible satellite image of Hurricane Hugo taken on September 16, 1989. Image credit: Google Earth rendition of the NOAA HURSAT data base.

Jeff Masters

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Quoting antonio28:


Welcome back Kman! Unussual low 70 sept night here in PR.


Hi there

Sounds really nice. Flew over you last Friday on the way back from Barbados LOL

Nice smooth ride.
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Quoting kmanislander:
Good evening all

I have not been on for the past 10 days or so due to travel obligations and the absence of activity. Just thought I would stop by to say hello.

Not a lot out there to speak of and little on the horizon. An unbelievably quiet peak season.

Looks like some rain on the way for the NW Caribbean when the ULL gets here.
You don't think there is any chance for something to develop from the blob west of the Antilles ?
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Quoting stormwatcherCI:
You know, I don't remember half of these but remember some really bad Nor'westers where the whole waterfront in GT was severely damaged.

Mitch in 98,Michelle 2001,Wilma 2005, and Dean 2007 affected us worst than some of those listed even though Mitch, Michelle and Wilma was like 140-160 miles at closest approach, Dean was like 80-100 miles. The Nor'wester of Christmas Day 1989 destroyed Northwest point , WestBay and did plenty damage downtown.
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Quoting kmanislander:
Good evening all

I have not been on for the past 10 days or so due to travel obligations and the absence of activity. Just thought I would stop by to say hello.

Not a lot out there to speak of and little on the horizon. An unbelievably quiet peak season.

Looks like some rain on the way for the NW Caribbean when the ULL gets here.


Welcome back Kman! Unussual low 70 sept night here in PR.
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Quoting hydrus:
I am curious to know how powerful were the winds there with charlie in gusts.
12 / 1200 19.2 80.7 984 80This is winds about 60 miles off Grand Cayman
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Good evening all

I have not been on for the past 10 days or so due to travel obligations and the absence of activity. Just thought I would stop by to say hello.

Not a lot out there to speak of and little on the horizon. An unbelievably quiet peak season.

Looks like some rain on the way for the NW Caribbean when the ULL gets here.
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Quoting Weather456:


I stand to be corrected but I agree.
Check out the link stormpetrol posted. It is an eye opener for me and a big surprise since I don't remember some of them.
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All quiet in the Atlantic Basin at the peak of the hurricane season no storm in the horrizon, not know and not likely for the rest of Sept. As predicted by almost all experts of this science. 6-2-2 will end 8-3-2 IMO.
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1001. hydrus
Quoting Weather456:


I stand to be corrected but I agree.
I am curious to know how powerful were the winds there with charlie in gusts.
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Quoting stormpetrol:
Link
Interesting site regarding the frequency of hurricane/storm hits.
Very interesting, I like that information. Alot of the storms that effected the islands effected s.w.Fl. like the 1873 storm, that one leveled us...
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Quoting stormwatcherCI:
I don't know where they get the info from and I have been living here since 1973 and I know I remember quite a few but for some reason there are only a few that really stand out. Ivan(of course), Michelle, Charley, Gilbert, Wilma, Emily, Dean, Gustav,Paloma and a few more but not enough that I would say most strikes. Then again, I am no expert.


I stand to be corrected but I agree.
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Quoting stormpetrol:
Link
You know, I don't remember half of these but remember some really bad Nor'westers where the whole waterfront in GT was severely damaged.
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993. JLPR
Quoting btwntx08:

its there but not closed lol


there are no north, south or west winds = no circulation
it needs to work on its LLC to try and come back
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Usually I am concerned about the models being wrong, but right now I am concerned about them being right. Most of the models show the low pressure feature currently over the Arklatex region (the one that drenched Texas, Oklahoma, and us in rain for days) moving just off the coast of Louisiana and then up and away to the East coast. Well, my concern is that the steering currents are correct short-term, but incorrect long-term. I don't want that thing to make it into the GoM. It has proven that it is all too happy to tap into the Gulf moisture over land, and I fear it having unrestricted access to the heat stored in the GoM.
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I think Ana was the most talked about storm on this blog this year so far. Wow, Ana beats Bill!
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Link
Interesting site regarding the frequency of hurricane/storm hits.
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Quoting hydrus:
What about Gilbert And Allen?
I don't know about Allen but no deaths from Gilbert and the damage was a lot less than you would think. Some structural damage, a lot of downed trees and road damage but power was up by the following day and some areas were only out for a few hours.
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Quoting Murko:


Help4u is Stormno/Stormt in disguise
lol..Its Sybil all over again..aaahhhh!!
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Link
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Quoting severstorm:
Hey all, I think that Dr Masters had a blog back when about the most hit by hurricanes and i think your right it was the Cayman Islands.
I don't know where they get the info from and I have been living here since 1973 and I know I remember quite a few but for some reason there are only a few that really stand out. Ivan(of course), Michelle, Charley, Gilbert, Wilma, Emily, Dean, Gustav,Paloma and a few more but not enough that I would say most strikes. Then again, I am no expert.
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Quoting JLPR:
Also some winds with the Blob in the E. Caribbean

Yeah, that area just looks nasty anyway.
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Quoting stormwatcherCI:
Well, Ivan was the worst and then there has been quite a few close brushes with some major hurricanes that I can remember but also a few years where nothing much came near and thank God not a lot of deaths since the 1932 hurricane. Only two in Ivan.
What about Gilbert And Allen?
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Night all.
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979. JLPR
Also some winds with the Blob in the E. Caribbean

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Hey all, I think that Dr Masters had a blog back when about the most hit by hurricanes and i think your right it was the Cayman Islands.
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Quoting reedzone:
I'm predicting 2 to 3 more named storms for the rest of the 2009 season
Then 2010?? Probably 12 or more. We'll see I guess


I'm willing to bet that 2010 will have at least 15 named storms. Historically speaking, the year after an El Nino (assuming that El Nino does not persist beyond a single year, of course, as occurred from 1991-1994) is quite an active one. A recent example of this is 2007, and before that, 2005.
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976. JLPR


yep the LLC is definitely gone
but there are still some winds with was is left of Ex-Fred
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Danny was never a real threat I always knew it...but gotta say how much I miss Ana.
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974. CUBWF
Quoting BahaHurican:
Cuba gets 'em from every direction.... N, S, E, W, and all of the lesser compass points.... lol... poor Cuba also seems to be in the recurve zone...

Hi Baha, also Cuba has the longest hurricane season. It stay 365 days a year, has been continue for 50 la niña years, no wind sheer, and waters temp. 40 degrees. All of the impact has been cat 5. Since then no electricity, waters, roof, etcccc. LOL
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Quoting hydrus:
I would say so, I have seen the caymans get hit many times (bad).
Well, Ivan was the worst and then there has been quite a few close brushes with some major hurricanes that I can remember but also a few years where nothing much came near and thank God not a lot of deaths since the 1932 hurricane. Only two in Ivan.
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972. Murko
Quoting BurnedAfterPosting:
2009 season is over?

LMFAO I have never heard anything so stupid in my entire life, its no wonder the joker is blocked by just about everyone LMAO




Help4u is Stormno/Stormt in disguise
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Quoting laflastormtracker:
Weather456-sat of Danny? lol!


comedy is a very tricky art isnt it?
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Quoting laflastormtracker:
Weather456-sat of Danny? lol!


Typhoon Choi-Wan
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Weather456-sat of Danny? lol!
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Quoting stormwatcherCI:
The Cayman Islands have the dubious honor of having experienced the most hurricane strikes in history. Due to the proximity of the islands, more hurricane and tropical systems have affected the Cayman Islands than any other region in the Atlantic basin (brushed or hit every 2.23 years).[4]
I would say so, I have seen the caymans get hit many times (bad).
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Quoting Ameister12:

I'm not saying hurricane season 2009 is other. I'm just discussing about next year. I'm thinking 2 more storms this season.


wasnt talking about you, I was talking about that joker help4u; who is the leader of the trolls

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Quoting Ameister12:

He's probably making new viruses for Windows.
He can just borrow one these days.
Member Since: September 27, 2007 Posts: 1 Comments: 22712
Quoting BurnedAfterPosting:
2009 season is over?

LMFAO I have never heard anything so stupid in my entire life, its no wonder the joker is blocked by just about everyone LMAO



I'm not saying hurricane season 2009 is other. I'm just discussing about next year. I'm thinking 2 more storms this season.
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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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