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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608. Halyn
Quoting hurricanehanna:

*bolts up from nap* whoa....someone toss an offering into the Atlantic quick!



Where is WS when you actually have a use for him ??
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Quoting Tejano72:
As we begin our 11th consecutive sunless day and our 10th inch of precipitation, I'd like to posit: "If this was over the GOM, what would it be?" - Signed, Damp in DFW

Nice "eye" over Texarkana...

Link


hey, where are you from? I was born in Atlanta
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been extremely busy. We are doing a group of properties for the local bank. Comercial properties are hot right now so all the locals are getting their assests in order!
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Quoting Floodman:


It seems that I've seen someone in here post IR images showing the cooler areas after passage...the answer, I think, is yes and no...the wave action tends to blend the edges a little but the track is apparent for some time after passage. again, I could be wrong, but I remember someone posting images of what you're talking about in '05


How long do you think it takes for the SST's to recover to "normal" after Bill? I live in Nova Scotia and we've already had two 'canes pass overhead here. Cat2 Juan slammed us in 03, although that was a direct hit.

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As we begin our 11th consecutive sunless day and our 10th inch of precipitation, I'd like to posit: "If this was over the GOM, what would it be?" - Signed, Damp in DFW

Nice "eye" over Texarkana...

Link
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Hey Floodman - How did you do sacrifices back in the Mayan empire days?
Member Since: March 10, 2006 Posts: 0 Comments: 10034
Quoting JupiterFL:


"Swirls Gone Wild"


coming soon to the virgin islands
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Just checking in for the day....

Anything new trying to stir up? or is it still quiet?
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Quoting weathermanwannabe:
Getting ready to head out for the day but in looking at the "big picture" WV loop for the Atlantic it looks to me like the following headline: "Multiple Naked Swirls, Surrounded by Dry Air and ULLs, headed WEST in the Atlantic and Caribbean toward the US and Caribbean!".....Where they go and what happens to them over the next several days is anyones guess.... :)


"Swirls Gone Wild"
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Quoting Floodman:


Are you saying that Tim Tebow is a poofter?

bTW, someone with a Jerry Garcia like icon should know better than to use a pejorative term like "poofter,"..they risk being called rednecks and hillbillies
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Quoting ElConando:


"Yo Dakster-ster whats a Diepaur I heard babies need them?"

lol remember when he started to spell wrong on purpose, the whole blog wanted to kill him...


Yep... to quote Bugs Bunny, what a maroon.
Member Since: March 10, 2006 Posts: 0 Comments: 10034
Quoting Dakster:


After reading his posts here, would he even know how to have a kid?

He may ask here for instructions...

LOL.
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The eye of Choi-Wan looks very similar to Katrina's eye.






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Quoting Dakster:


After reading his posts here, would he even know how to have a kid?

He may ask here for instructions...


"Yo Dakster-ster whats a Diepaur I heard babies need them?"

lol remember when he started to spell wrong on purpose, the whole blog wanted to kill him...
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Thanks for the comments on my blog guys!
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Quoting Floodman:


Oh man, it's pretty obvious you've never been there...LOL


The ISLANDS are virgins, not necessarily the people that live on them! lol...
Member Since: March 10, 2006 Posts: 0 Comments: 10034
590. JLPR
Quoting OracleDeAtlantis:
Watching the last few frames of the visible imagery of Freddy, it appears as if the lower level circulation has moved ahead of the ULL, which is now sitting to the southeast side. It's hard to tell if he still has a closed circulation, however. My guess is, that it's not a closed low at the surface, but at the mid levels.

Whether it can regenerate or not remains to be seen, but let's face it, if it hadn't stayed this weak for this long, it would have been a fish. It's current weakness may end up being our Achilles heel.



There is no closed circulation anymore
Member Since: September 4, 2007 Posts: 36 Comments: 5223
588. jipmg
Any latest imagery of choi wang
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Quoting StormChaser81:


WS JR NOOOOOOOOOOOOOOOOOOOOOOOOOOOO!!! He should have to file a certain document to the government, so they can debate the issue.


After reading his posts here, would he even know how to have a kid?

He may ask here for instructions...
Member Since: March 10, 2006 Posts: 0 Comments: 10034
Quoting Hurricane009:
I know. I spell checked it. Did my best anyway


Caribbean

Other than that the spelling was good
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Choi-wan has one big round eye and good outflow. Yesterday, I viewed an image in NRL and Choi-wan looks somewhat similar to Katrina.
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Quoting Dakster:


ROFLMAO. I never knew you had it in you Floodman.


Thank you...I saw the opening, and as you well know, in comedy one must srike while the iron is hot...LOL
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Hey Flood whats up anything popping out there today?
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Getting ready to head out for the day but in looking at the "big picture" WV loop for the Atlantic it looks to me like the following headline: "Multiple Naked Swirls, Surrounded by Dry Air and ULLs, headed WEST in the Atlantic and Caribbean toward the US and Caribbean!".....Where they go and what happens to them over the next several days is anyones guess.... :)
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Quoting Floodman:


LMAO...I hear them saying that in the Tropics Update:

Here's a little song I wrote
About the MJO down-stroke
Don't Worry
Be Happy!

The wind may be blowing hard outside
Your house is filling with the rising tide
Don't Worry
Be Happy!


ROFLMAO. I never knew you had it in you Floodman.
Member Since: March 10, 2006 Posts: 0 Comments: 10034
http://www.accuweather.com/mt-news-blogs.asp?partner=accuweather&blog=Weathermatrix&pgurl=/mtweb/cont ent/Weathermatrix/archives/2009/09/amazin_satellite_images_of_typhoon_choiwan.asp

I have this picture comparing if this storm was put over the US, can't figure how to post but will put in my pictures
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Quoting Hurricane009:
I know. I spell checked it. Did my best anyway


good job, I only noticed 2 words
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Watching the last few frames of the visible imagery of Freddy, it appears as if the lower level circulation has moved ahead of the ULL, which is now sitting to the southeast side. It's hard to tell if he still has a closed circulation, however. My guess is, that it's not a closed low at the surface, but at the mid levels.

Whether it can regenerate or not remains to be seen, but let's face it, if it hadn't stayed this weak for this long, it would have been a fish. It's current weakness may end up being our Achilles heel.

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Good evening everyone!
Interesting AOI in the Caribbean.

AOI and ex-Fred.


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Quoting Hurricane009:
Blog Posted earlier for people that did not know. I talked about Ex - Fred, The Tropical Wave off the coast of africa, the distrubance south of Puerto Rico, and the Strong Cold front coming. You should see it. Very informative.


I commented
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Quoting hurricanehanna:

thy shear and thy ridge, they protect thee...

okay, I know, it's reaching a little


LOL
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Quoting canehater1:
Saw QMS in Mobile, AL at Ladd Stadium in the 70's They opened for Wet Willie and Allman Bros.---great show!


They're a great band, but in the late 60s, when everyone was going more and more grunge, they were long haired but clean cut, you know?
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Quoting JLPR:
that ULL is very interesting
it has now a strong 500mb(mid levels) vorticity



It does appear to be trying to transition to the surface...
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566. JLPR
that ULL is very interesting
it has now a strong 500mb(mid levels) vorticity

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


Yes. You can see broad tracks of cooler SST's in the wake of large hurricanes on the SST maps provided on the tropical resources page on this site. Bill left a clear path in the days/weeks following his passage. And yes, this cool water can and does interfere with the intensity of storms that follow.


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Quoting Floodman:
It's a well known fact that Quick Silver Messenger Service were all virgins until 1980
Saw QMS in Mobile, AL at Ladd Stadium in the 70's They opened for Wet Willie and Allman Bros.---great show!
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Quoting tfhoward:
The Atlantic hurricane scene is a bit slow right now, and this seems like a good time to ask a question I've had for a long time. We always hear that warm sea surface temperatures are the fuel for hurricanes. A hurricane removes heat from that surface through evaporation and then conveys it to higher altitudes and/or latitudes where it is released through condensation. The sea surface is thus cooled. My question is whether the cooled surface shows up in infrared satellite images. Does a hurricane leave a track behind it, or does wave action immediately mix the cooled surface water downward and erase any trace of the hurricane's passage?


Yes. You can see broad tracks of cooler SST's in the wake of large hurricanes on the SST maps provided on the tropical resources page on this site. Bill left a clear path in the days/weeks following his passage. And yes, this cool water can and does interfere with the intensity of storms that follow.
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Waterwitch, the link you have at the top of the post results in a 404 error
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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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