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 reedzone:


Look at the phrase..

"Fred COULD be the talk of 2009 Hurricane Season. "LOL"

I was just having fun yesterday, this wasn't really a prediction. However, it will probably be the talk of the season as the most longest and annoying storm this year.


Most longest??????
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Quoting ElConando:
Note: To 456 Northern Mariana islands has a population of about 80 thousand people. Just an FYI


cool
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Note: To 456 Northern Mariana islands has a population of about 70 thousand people. Just an FYI
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Radar Doppler punta cana, Republica Dominicana a las 9:46 am
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It will be interesing to see if this ridge does what it is forecasted to do and keeps Fred on more westerly track.
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Quoting reedzone:
Point is, I wasn't wishcasting storms. I was banned and called a wishcaster on Flhurricane for predicting Humberto in 2007 to at least get up to 65 mph. and look what it did. With the conditions it was in, there was no reason for me to keep it as a 45 mph. storm with the rate it was growing. I was called a "Newcaster" for predicting Bill this year to possibly brush Cape Cod, in which it did with heavy rain bands and some wind. How did I make the predictions? Steering and patterns! I didn't just draw the map out for fun, it was accurate; however, and I'll admit, Bill did not hit Nova Scotia as I predicted.


Boy I wish I knew you in 2007. :) The unexpected 90mph was quite an eye opener. Especially since out locals said it was no big deal.

Where are my manners? Good morning Reed. Good morning all. :) Can't stay sad to say. Y'all play nice. And be greatful things are slow enough for you to have time to bicker.
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54. JRRP
i see the clouds is moving SE to NW here in santo domingo
and a few cumulonimbi.. looking east
Link
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Quoting jipmg:


and CMC

@weather456

Why is it moving West again, its supposed to be moving NW-NNW


it could be a jog.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
With a trough reaching the east coast in 7-8 days, we may not see the last of Fred.
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Time to go to work.... play nice.



AOI

AOI

AOI

AOI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting rwdobson:
"Only the HWRF model redevelops Fred"

the same model that brought us Major Hurricane Danny and Major Hurricane Erika strikes again...


and CMC

@weather456

Why is it moving West again, its supposed to be moving NW-NNW
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The latest HWRF still keeps a little activity around Fred for awhile.
Member Since: July 17, 2009 Posts: 71 Comments: 26156
2009/259 - 09/16 at 01 :25 UTC
Super Typhoon Choi-wan (15W) west of the Mariana Islands, Pacific Ocean
Satellite: Terra



Member Since: July 24, 2005 Posts: 407 Comments: 19076
"Only the HWRF model redevelops Fred"

the same model that brought us Major Hurricane Danny and Major Hurricane Erika strikes again...
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Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting SeniorPoppy:


hmmm... nice spin southwest of Puerto Rico


Its an upper level low..
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43. JRRP
Quoting SeniorPoppy:


hmmm... nice spin southwest of Puerto Rico

ULL..
as 456 said... this is being caused by upper diffluence south of the upper low
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Children, children. It's ok to agree to disagree.
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Quoting TheDawnAwakening:
It looks like an upper level low southwest of Puerto Rico and could be trying to work to the surface. I certainly am not sure about that though.


Its a tight one as 456 said on the previous blog. It is moving at a rather fast clip and with the situation in the Western Caribbean I hope it doesn't get there.
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Quoting TampaSpin:
Looks like our Trough protection will be gone for the next 7 days or more...as the Bermuda high builds west into the ConUs.


You may be on to something Tampa with the system south of Hisp.
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It looks like an upper level low southwest of Puerto Rico and could be trying to work to the surface. I certainly am not sure about that though.
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That was an amazing cloudsat image of Choi-Wan. Just an amazing tool to use when it hits the hurricane head on. Choi-Wan is a massive storm and I really like the Hugo stories and pictures, thanks Dr. Masters.
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Quoting JRRP:


hmmm... nice spin southwest of Puerto Rico
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Quoting Nolehead:
so nothing about the 5 year anniversary of Ivan?? granted Hugo was big also, but can't forget about this storm that almost came back twice.....or did i miss it in the last blog??
hard to beleive it has already been five years since I woke up to ivan's devastation!
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34. LBAR
Ah, yes, "Iris". I remember hearing some rumors of another big hurricane coming in after Hugo along roughly the same path. (We had no power...just wild rumors). Thankfully that didn't happen.

Fred's remnants would be a welcome sight in central South Carolina and North Carolina. Dry as a bone, especially in South Carolina.
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Point is, I wasn't wishcasting storms. I was banned and called a wishcaster on Flhurricane for predicting Humberto in 2007 to at least get up to 65 mph. and look what it did. With the conditions it was in, there was no reason for me to keep it as a 45 mph. storm with the rate it was growing. I was called a "Newcaster" for predicting Bill this year to possibly brush Cape Cod, in which it did with heavy rain bands and some wind. How did I make the predictions? Steering and patterns! I didn't just draw the map out for fun, it was accurate; however, and I'll admit, Bill did not hit Nova Scotia as I predicted.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
32. JRRP
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30. JRRP
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Looks like our Trough protection will be gone for the next 7 days or more...as the Bermuda high builds west into the ConUs.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting TampaSpin:


Reed i have to disagree with you about Erika! Some did get it right on the money!


I dont know why that has been circulating that no one got Erika right. Some did. It was not perfect but there is no perfect forecast.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting reedzone:


Again and again and again I stated Bill will probably brush New England, not directly hit. I said watch for any changes. Everybody was wrong on Erika, she was a storm that nobody got right, I was right on Dannys path, but not his strength. I don't think I slammed anyone with a category 5 hurricane yet, will not until something like that is coming which is very low for another month.


Reed i have to disagree with you about Erika! Some did get it right on the money!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting gulfcoastdweller:



BEST POST OF THE SEASON


Look at the phrase..

"Fred COULD be the talk of 2009 Hurricane Season. "LOL"

I was just having fun yesterday, this wasn't really a prediction. However, it will probably be the talk of the season as the most longest and annoying storm this year.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
Thank You for the update Dr. Masters
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Quoting tropicofcancer:
1509. reedzone 9:41 AM EDT on September 16, 2009
I've noticed the NHC dropped Invest Fred (again). They need to keep it, there just not doing good this year with the exception of Bill.

On the orher hand if we had followed YOUR forecasts for all system this year, We would have been boarded up in a cave for the last 6 months!


Again and again and again I stated Bill will probably brush New England, not directly hit. I said watch for any changes. Everybody was wrong on Erika, she was a storm that nobody got right, I was right on Dannys path, but not his strength. I don't think I slammed anyone with a category 5 hurricane yet, will not until something like that is coming which is very low for another month.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
IKE i love your wit. Gotta say you do tend to lean toward the downcast side but, there is nothing wrong with that in my mind. You just like to see more facts before jumping to the other side. I would say 90% of poster on here are Wishcasting bloggers...I wish there was alot more like IKE on here. IKE and i don't always agree but, its never an ill feeling toward us both. He is very good at his analysis! Keep up the good work IKE!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Roger that DOC, I just barely escaped that storm while it was forming Near GUAM.

Iwo Jima area is going to get messed up bad from it. Already planning relief efforts there. And one island north of Siapan got hit hard as well.

Tokyo looks like it'll be spared according to current JTWC track, Upper levels are showing recurvature soon as well.

But ya 90 degree waters, low shear and massive ammount of LLC a few days ago we knew the storm was going to blow up fast here at 7th fleets weather hub.

Well thats my blurb.. See ya guys around!
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Quoting IKE:
Since I was hammered on the other blog, I must respond....




Now remember...you started this, not me.

"Downcast every system"? LOL. When did I downcast the GOM blob? When did I downcast Bill?

"Give it time"...we're talking about the weather here, not someone saying you have 6 months to live because of terminal cancer. It's the weather.


"""please keep it limited on here, you're gonna get people active."""....

I'll say what I want to.


You on the other hand are what I call a wishcaster...

"""reedzone 6:22 PM CDT on September 15, 2009
Fred could be the talk of the 2009 season in the end. LOL"""


Ok, you don't downcast every system, I was wrong on that. and if you read a few posts after that, I said I have respect for you because you went through alot which is why you don't predict much for the USA. I'm sorry IKE, but I'm NOT a wishcaster, sure I'd like a strong TS, but not a major Hurricane. If you also look, I said you base your points with facts unlike others, which makes you a person I can trust. I didn't mean to go all the way to say you downcast every storm, but you do downcast some, but in good ways, nobody wants a Hurricane to hit them, unless they are kids. I predict by patterns and steering, and sometimes go by models. I base my forecasts on facts and you KNOW this. However, you had a right to attack me, I was wrong by stating that paragraph.
Member Since: July 1, 2008 Posts: 13 Comments: 7390
1509. reedzone 9:41 AM EDT on September 16, 2009
I've noticed the NHC dropped Invest Fred (again). They need to keep it, there just not doing good this year with the exception of Bill.

On the orher hand if we had followed YOUR forecasts for all system this year, We would have been boarded up in a cave for the last 6 months!
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I wore Dr. Masters down!!!! It's exactly the same way I got my wife to marry me...sometimes it's just easier to give in and go along...
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Quoting presslord:
Jeff Masters: "...into South Carolina/North Carolina..."

Yes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!



Oh man.... I thought we had slowly gotten everyone to agree.. "Carols"
Member Since: October 1, 2007 Posts: 81 Comments: 26511
13. IKE
Since I was hammered on the other blog, I must respond....


Quoting reedzone:


I'm sorry IKE, but Weather456 has a point. You downcast every system, Fred is still a long time away from destruction, can still organize if it gets to the Bahamas. Calling this dead was premature. Anyone RIPing Fred is premature. Give it time, Fred may or may not do anything. Downcasting the system won't do anything but get people on here mad. Although, nobody wants a Hurricane, some people do, and there most likely kids and have not experienced a Hurricane like you and I. Ivan and Dennis was no joke IKE, I feel you're pain on that. I went through Charley and Frances here in Northeast/Central Florida. I understand why you downcast storms, but please keep it limited on here, you're gonna get people active.
Point is, Fred can redevelop at any time, systems like this have surprised people. It still needs to be watched.


Now remember...you started this, not me.

"Downcast every system"? LOL. When did I downcast the GOM blob? When did I downcast Bill?

"Give it time"...we're talking about the weather here, not someone saying you have 6 months to live because of terminal cancer. It's the weather.


"""please keep it limited on here, you're gonna get people active."""....

I'll say what I want to.


You on the other hand are what I call a wishcaster...

"""reedzone 6:22 PM CDT on September 15, 2009
Fred could be the talk of the 2009 season in the end. LOL"""
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Thanks for the update Dr. M
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so nothing about the 5 year anniversary of Ivan?? granted Hugo was big also, but can't forget about this storm that almost came back twice.....or did i miss it in the last blog??
Member Since: June 3, 2008 Posts: 0 Comments: 1930
Jeff Masters: "...into South Carolina/North Carolina..."

Yes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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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.