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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759. JLPR
Quoting Weather456:


Georges was the reason. The other reason is that my country is only 2nd to Cuba for the Caribbean with the most hurricane strikes.

I have lived through

Hugo
Luis
Marilyn
Bertha
Georges (the costliest)
Lenny
Omar

Only Bertha wasnt a major when it passed.



Lets see =] I have on my List
Storms that brought winds to PR or made landfall:
H Luis (95)
H Marilyn (95)
H Bertha (96)
H Hortense (96)
H Georges (98)
TS Jose (99)
H Lenny (99)
TS Jeanne (04)

those are the ones in my Lifetime =]
Member Since: Posts: Comments:
756. HadesGodWyvern (Mod)
Tropical Cyclone Advisory
Typhoon 0914 - Choi-wan

1800UTC 16 September 2009
Center Location 19.6N 141.4E
Movement NW 11km/hr
Minimum Pressure 915hPa
Maximum Wind Speed 55m/s
--
oh look the intensity went up to 110 knots from the Central Bureau Weather in Taiwan
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Quoting viman:


<---Another Hugo survivor in the Virgin Islands.
Yeah, I was 23 at the time. It was all over the news how devastating the damage was. I remember all the yachts piled on top of each other, trees and homes leveled, people here in the U.S. were starting to worry.
Member Since: September 27, 2007 Posts: 1 Comments: 21869


AOI

AOI

AOI

AOI
Member Since: Posts: Comments:
Quoting hydrus:
You got whacked by Hugo too? No wonder you study meteorology.


Georges was the reason. The other reason is that my country is only 2nd to Cuba for the Caribbean with the most hurricane strikes.

I have lived through

Hugo
Luis
Marilyn
Bertha
Georges (the costliest)
Lenny
Omar

Only Bertha wasnt a major when it passed.

Member Since: Posts: Comments:
Quoting Ameister12:

What about 90S?

Oh!
This is 90S.
Member Since: August 9, 2009 Posts: 10 Comments: 5077
749. HadesGodWyvern (Mod)
742. Ameister12 11:04 PM GMT on September 16, 2009

90S was Tropical Disturbance 01R-20092010 in the southwest Indian Ocean

It was designated by Mauritius Meteorological Services as a disturbance and numbered.

01-20092010 advisory last month
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748. viman
Quoting hydrus:
You got whacked by Hugo too? No wonder you study meteorology.


<---Another Hugo survivor in the Virgin Islands.
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Quoting BurnedAfterPosting:
What is a hurricant?

is that the opposite of a hurrican?

Lmao!
Member Since: August 9, 2009 Posts: 10 Comments: 5077
Quoting TexasHurricane:
"There will be no Gulf hurricanes this year, as alreay forecast at the start of the season."

There may not be any this year, but still seems odd to say there will be none, when we aren't done with the season yet....

They said development if any would be close to land, but i'm with ya on the "no hurricanes in the gulf".
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Quoting HURRICANECAT5:
Can someone please post the LATEST intesity model predictiond for EX FRED. Thanks.


ZERO - ZIP - NADA - 0
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Quoting HadesGodWyvern:


Australia satellite imagery showing 91S

What about 90S?
Member Since: August 9, 2009 Posts: 10 Comments: 5077
What is a hurricant?

is that the opposite of a hurrican?
Member Since: Posts: Comments:
My thoughts:

AOI near 13N 32W a FAIR(25-40%) chance of tropical development in the next 72 hours.

AOI near 20N 51W a VERY LOW(>10%) chance of tropical development in the next 72 hours.

AOI near 15N 70W a VERY LOW(>10%) chance of tropical development in the next 72 hours.

These are based on current conditions.
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738. IKE
Quoting hunkerdown:
did anyone tell you you are a "coldcaster ? :)

...and, I have heard that forecast before. People can't even forecast today and tomorrow, why believe in anything long term.


Gotta have faith.....it'll happen.
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Quoting Hurricane009:
Dr. Master is predicting a terrible hurricant to hit USA


And where are you reading this? I must have missed it in his blog?
Member Since: March 10, 2006 Posts: 0 Comments: 10572
Unusual El Nino hits Australia
September 16, 2009 - 6:03PM

El Nino is here - but it's a weird one.

The weather bureau says Australia is experiencing an El Nino weather pattern, which sweeps in from the Pacific Ocean and usually brings hot, dry weather to eastern states.

It's expected to last at least until the end of the year.

But the latest El Nino update, issued on Wednesday, says it's an "unusual" cycle because of warm conditions in the Coral Sea, off Australia's north coast, and in the far western tropical Pacific.

These areas are usually cooler than normal during an El Nino.

The update noted the country's east had been dry and very warm recently, as consistent with El Ninos.
Member Since: Posts: Comments:
Quoting IKE:
Nashville,TN. extended says it all....

"LONG TERM...
POLAR TROUGH DROPS SOUTH WITH SCATTERED PCPN THIS WEEKEND. MAJOR
COLD FRONT SWEEPS THOUGH TUE NIGHT...WITH A DECENT AMOUNT OF SUN
RETURNING BY MIDWEEK.".....


and NO,LA extended....

"WILL
SEE DRIER AND COOLER AIR TUESDAY NIGHT AND WEDNESDAY.".....


Bring it on!


did anyone tell you you are a "coldcaster ? :)

...and, I have heard that forecast before. People can't even forecast today and tomorrow, why believe in anything long term.
Member Since: Posts: Comments:
Quoting Weather456:


I was 14 months old. But it was the 1st hurricane in my lifetime.
You got whacked by Hugo too? No wonder you study meteorology.
Member Since: September 27, 2007 Posts: 1 Comments: 21869
Quoting seminolesfan:
Nice Guesscast there buddy!


semenolesfan - How do you know this? There are plenty of years without a CONUS Cane hit....
Member Since: March 10, 2006 Posts: 0 Comments: 10572
730. IKE
Nashville,TN. extended says it all....

"LONG TERM...
POLAR TROUGH DROPS SOUTH WITH SCATTERED PCPN THIS WEEKEND. MAJOR
COLD FRONT SWEEPS THOUGH TUE NIGHT...WITH A DECENT AMOUNT OF SUN
RETURNING BY MIDWEEK.".....


and NO,LA extended....

"WILL
SEE DRIER AND COOLER AIR TUESDAY NIGHT AND WEDNESDAY.".....


Bring it on!


Member Since: Posts: Comments:
729. HadesGodWyvern (Mod)


Australia satellite imagery showing 91S
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Quoting ElConando:


What I am also anticipating is the upward pulse of MJO from the end of Sept till mid oct. homegrown Caribbean development is defiantly possible.
My thinking too, PLUS... the bathwater down there,PLUS..the shear could be much less..Maybe,..probably.jmo..
Member Since: September 27, 2007 Posts: 1 Comments: 21869
Can someone please post the LATEST intesity model predictiond for EX FRED. Thanks.
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Quoting ElConando:


Did you experience the wrath of Hugo 456?


I was 14 months old. But it was the 1st hurricane in my lifetime.
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Quoting Weather456:


Happy Independence from Saint Kitts right across the Sea.


Did you experience the wrath of Hugo 456?
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Quoting KEEPEROFTHEGATE:
i kinda like calling it a shot in the dark but who really knows as we progress into late sept early oct be on the lookout for the eastward trackin systems and there is only 3 places they occur normally thats the sw atlantic the nw carb. and the gom the season ends at 11 59 pm est nov 30th 2009 75 days from now


What I am also anticipating is the upward pulse of MJO from the end of Sept till mid oct. homegrown Caribbean development is defiantly possible.
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Member Since: Posts: Comments:
Quoting Nevis1:
"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.



The damage from HUGO is STILL visible on Nevis today. The entire island of Monteserrat was in the eye.


Happy Independence from Saint Kitts right across the Sea.
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Quoting HURRICANECAT5:
Does anybody have the latest intesity forecast from the models on EX Fred?

I have them.
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719. HadesGodWyvern (Mod)


91S near Indonesia
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Some repost from today

Perfect conceptual model of the Tropical Upper Tropospheric Trough (TUTT) and Fred is right in the middle.



Today's Tropical Update

Yesterday's post - Structure of a tropical cyclone: Microwave Imagery of Choi-Wan

2009/259 - 09/16 at 01 :25 UTC
Super Typhoon Choi-wan (15W) west of the Mariana Islands, Pacific Ocean
Satellite: Terra



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Quoting KerryInNOLA:
The long awited KNOLA team forecast for the rest of the hurricane season is out.ExFred will remain FredEX. We are in for fairly smooth sailing. Only 2-3 more hurricanes with no major hurricanes.The shear that has blessed us will ease a little, but the fronts will start next week and keep most action away from the coast. There will be no Gulf hurricanes this year, as alreay forecast at the start of the season. There is a good chance of an October surprise for the mid-Atlantic area. November will be a lamb. KNOLA is proud to be your #1 independent forecast source with no political ties. We accept no government cheese.We will be analyzing new data and if something new pops up we will let you know.

WARNING!! These forecasts in no way relieve the individual from personal responsibility during hurricane season. Always keep up your guard! You could go to sleep one night safe and sound with no hurricanes on the horizon and wake up tomorrow, due to global warming with a CATEGORY 5 HURRICANE only hours away from landfall!


lol, such pride!!!! So what was that website again. You mentioned it a couple days ago. I'm real curious as to what it's all about.
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Quoting KerryInNOLA:
It's called a forecast, an opinion, not etched in stone.
i kinda like calling it a shot in the dark but who really knows as we progress into late sept early oct be on the lookout for the eastward trackin systems and there is only 3 places they occur normally thats the sw atlantic the nw carb. and the gom the season ends at 11 59 pm est nov 30th 2009 75 days from now
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Does anybody have the latest intesity forecast from the models on EX Fred?
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Quoting centex:
That pesky low is moving back into Texas.


It has impressive circulation. It looks like a hurricane that had moved ashore. You can even sort of see a 50 mile diameter eye to it over Texarkana (sort of).
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Quoting katlbeach:


A little more contemporary
"I kissed a swirl and I liked it" :-]
I cannot remember who did that one.
Member Since: September 27, 2007 Posts: 1 Comments: 21869
Quoting iceman55:
TexasHurricane .?


What?
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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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