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 winter123:


hahaha, tilt your head a bit left and yeah i agree


Glad im not crazy. Well sorta :)
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Quoting winter123:


hahaha, tilt your head a bit left and yeah i agree
OMG!!! it is a face
Quoting NWHoustonMom:


why "lol" on that?

you put "lol" on almost everything you post... I'm confused???

fixed i put a link of my radar
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Anyone thinks exFred maybe developing a surface circulation again. Still think the ULL/MLC SW of PR bears watching.
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Quoting NWHoustonMom:


why "lol" on that?

you put "lol" on almost everything you post... I'm confused???


Not even freud could figure him out lol

or is that no lol?
Quoting btwntx08:
well today our nws said no chance of rain yet showers/t-storms developing they got it wrong lol


why "lol" on that?

you put "lol" on almost everything you post... I'm confused???
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503. JLPR
Well the ULL definitely has left a good amount of rain behind =P
its raining here, and quite hard, although there is no thunder :)
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting alaina1085:


Holy cow it looks like a face! The swirls are the eyes... im serious, check it out.


hahaha, tilt your head a bit left and yeah i agree
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WaveTrak Winds and Vorticity
Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting sailingallover:
There is a tropical wave associated with all the convection near the upper level low SW of PR..
Question is will the upper level low enhance the waves ability to developt into a TS or simply enhance the convection while keeping it from organizing...it is heading towards a lot of really warm water..
http://www.goes.noaa.gov/pr1.html


There is no tropical wave in the East Caribbean
Afternoon,to all,dropping in briefly.Not much going on,hope everyone's got their autumn clothes ready,very deep trough for the central part of the country next week is going to chill things all the way to the gulf.
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Quoting BurnedAfterPosting:


If I am not mistaken the saying goes

"Give a man a fish, feed him for one night."

"Teach a man to fish, and feed him for a lifetime."


What happens if you give him a sardine? I mean, you couldn't eat for one night on a sardine, huh? Guess it depends on the size of the sardine...or the person...
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Quoting BurnedAfterPosting:


I actually liked your saying lol, I was agreeing with you
Oh, I know you were. It was just after reading the parable in your post I had the mental image of GWB reading mine. I was just sharing the thought.

You doin' alright today?
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There is a tropical wave associated with all the convection near the upper level low SW of PR..
Question is will the upper level low enhance the waves ability to developt into a TS or simply enhance the convection while keeping it from organizing...it is heading towards a lot of really warm water..
http://www.goes.noaa.gov/pr1.html
Member Since: Posts: Comments:
Quoting btwntx08

i was first in posting he should be thanking me lol

congrats, here is a cookie
well today our nws said no chance of rain yet showers/t-storms developing they got it wrong lol
Link
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Caribbean GOES-12 WV False Color CH-3



Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting seminolesfan:
Congratulations you've won the internet!!!


compliments of Al Gore!!!
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Quoting Patrap:


CHillin,looking at the ESL Site,..thinking about fall,and sweaters.

Love sweaters..Harumph,..


LOL


There's nothing wrong with sweaters...now that Isaac Hayes cape, on the other hand...LOL
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Quoting btwntx08:

i was first in posting he should be thanking me lol
Congratulations you've won the internet!!!
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Quoting seminolesfan:
What's the matter BAP? Didn't like how I ran that one through the "GWBush Parable-izer 3000"?


I actually liked your saying lol, I was agreeing with you
Quoting JLPR:
When there is a floater on a ULL you know its quiet lol xD

Link


When theres a floater on a ULL,..its Usually Mid September
Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting BurnedAfterPosting:


If I am not mistaken the saying goes

"Give a man a fish, feed him for one night."

"Teach a man to fish, and feed him for a lifetime."
What's the matter BAP? Didn't like how I ran that one through the "GWBush Parable-izer 3000"?
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Low Cloud Product GOES-12

Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting hurricanehanna:


Duct tape - one roll, many uses.
j/k


LMAO, yea im pretty sure I would need more then 1 roll for mine.
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Quoting hurricanehanna:

works great on roommates!


glad to hear that! now, time to make a wal-mart run! jk
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483. JLPR
When there is a floater on a ULL you know its quiet lol xD

Link
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting tornadodude:


LOL

can I use it on my roommate? he tends to snore a lot!

works great on roommates!
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ESL GOES-12 Atmospheric Imagery

These images are primarily for use in tropical storm monitoring. There are several areas to choose from providing a large-scale view of the Atlantic, down to the Gulf of Mexico. During hurricane season, the hurricanes page provides a variety of GOES atmospheric products to help monitor the active storms
Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting hurricanehanna:


Duct tape - one roll, many uses.
j/k


LOL

can I use it on my roommate? he tends to snore a lot!
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Quoting seminolesfan:
Every hear the story about teaching a man to fish?

Why did you give him such a small fish anyways?

i was first in posting he should be thanking me lol
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Quoting Floodman:


Am I really incrive? I have to say, I have the cape he's wearing there; it's a bad mutha...LOL

Where yat, Pat?


CHillin,looking at the ESL Site,..thinking about fall,and sweaters.

Love sweaters..Harumph,..


LOL
Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting alaina1085:


Holy cow it looks like a face! The swirls are the eyes... im serious, check it out.


haha yeah I see it
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Quoting alaina1085:


Tell that to my 2 year old who refuses to nap
:(


Duct tape - one roll, many uses.
j/k
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Quoting Patrap:
Atlantic Ocean View (Updated ~3 hours)

GOES-12 Channel 3 (WV)


Holy cow it looks like a face! The swirls are the eyes... im serious, check it out.
Member Since: Posts: Comments:
Quoting seminolesfan:
Every hear the story about teaching a man to fish?

Why did you give him such a small fish anyways?


If I am not mistaken the saying goes

"Give a man a fish, feed him for one night."

"Teach a man to fish, and feed him for a lifetime."
Quoting hurricanehanna:

*jumps* what???? it's quiet - we should be taking naps while nothing serious to monitor...cause it could come later. *closes eyes*


Tell that to my 2 year old who refuses to nap
:(
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Atlantic Ocean View (Updated ~3 hours)

GOES-12 Channel 3 (WV)
Member Since: July 3, 2005 Posts: 427 Comments: 129400
Quoting jipmg:


... wow thank you.. o-o
Very welcome, not a problem. I like helping people.
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Quoting alaina1085:


LOL.. *Taps Hanna on the shoulder, WAKE UP!!*

*jumps* what???? it's quiet - we should be taking naps while nothing serious to monitor...cause it could come later. *closes eyes*
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Quoting Patrap:
wu-stock 09 opener for Floodman


Am I really incrive? I have to say, I have the cape he's wearing there; it's a bad mutha...LOL

Where yat, Pat?
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Quoting btwntx08:
i posted a image no need to look at the link lol
Every hear the story about teaching a man to fish?

Why did you give him such a small fish anyways?
Member Since: Posts: Comments:
467. jipmg
Quoting seminolesfan:
Link


... wow thank you.. o-o
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Quoting hurricanehanna:
*stretches back, yawns...* Nothin' goin' on, eh?


LOL.. *Taps Hanna on the shoulder, WAKE UP!!*
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i posted a image no need to look at the link lol
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Quoting jipmg:
anyone have a rainbow satellite of the entire atlantic?here ya go...Link
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Quoting jipmg:
anyone have a rainbow satellite of the entire atlantic?
Link
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Quoting alaina1085:


Already read it, so far so good!


thanks!
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Quoting tornadodude:


It is a good idea ha

oh btw, I posted a new blog, your input is welcomed! thanks!


Already read it, so far so good!
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*stretches back, yawns...* Nothin' goin' on, eh?
Member Since: Posts: Comments:

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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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