Unusual Chantal Disorganized, but has 65 mph Winds

By: Dr. Jeff Masters , 8:06 PM GMT on July 09, 2013

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Unusual Tropical Storm Chantal has strengthened a bit more as it speeds west-northwestwards at 26 mph away from the the Lesser Antilles Islands. Sustained winds of 38 mph, gusting to 52 mph, were observed at Martinique at 10 am AST as the storm passed. However, an automated weather station at the airport measured sustained winds of 60 mph, gusting to 78 mph, according to an official with Meteo-France. The Associated Press reported that Chantal ripped the roofs off of several homes on neighboring Dominica. An Air Force hurricane hunter aircraft measured top winds at their 1,000' flight level of 89 mph at 12:55 pm AST. Top winds seen by the aircraft's SFMR instrument were about 65 mph, in a small area east of Chantal's center. The Hurricane Hunters have departed Chantal, and the next plane is due in the storm at 8 pm EDT. Chantal's winds are unusually high considering the storm's high central pressure of 1006 mb and disorganized appearance on satellite imagery. Chantal is fighting dry air associated with the Saharan Air Layer (SAL), as seen on water vapor satellite loops. This dry air is creating strong thunderstorm downdrafts that are robbing Chantal of moisture and energy. Visible satellite loops show the outflow boundaries of these thunderstorm downdrafts at the surface, spreading to the northwest of Chantal. Martinique Radar shows a large area of heavy rain that is not well-organized, lying mostly to the west of the Lesser Antilles Islands.


Figure 1. MODIS image of Chantal taken at approximately 1 pm EDT Tuesday, July 9, 2013. At the time, Chantal had top winds of 65 mph, but looked very disorganized, due to high wind shear and dry air. Dry air is creating strong thunderstorm downdrafts that are robbing Chantal of moisture and energy. Outflow boundaries from these downdrafts are spreading out to the northwest of Chantal, as seen on this satellite image. Image credit: NASA.

An small-scale easterly jet creating high shear in Chantal
Chantal is not very impressive on satellite images, with a modest amount of heavy thunderstorms that are not well-organized. Only a small amount of upper-level outflow is visible. The reason for Chantal's rather disorganized appearance can be found by looking at this morning's balloon sounding from Guadaloupe. This island was just northwest of the center of Chantal when the balloon was launched at 8 am EDT. The sounding showed typical easterly trade winds at the surface of 12 knots (14 mph.) However, the winds rose quickly aloft, with a jet of easterly winds of 35 - 53 knots between 800 - 600 mb (about 7,000 - 15,000'.) But, by the time the ballon hit 500 mb (18,000'), the winds had died down to 15 knots. A change of wind speed from 12 knots to 53 knots and back down to 15 knots from the surface to 500 mb is a tremendous amount of wind shear, which will make it very difficult for a tropical storm to keep the surface center aligned with the upper level center. The traditional measure of wind shear, the difference in wind between 200 mb and 850 mb, was 44 knots in this morning's Guadaloupe sounding, but was a much higher 56 knots from 200 mb to 700 mb. The powerful easterly wind jet was not apparent at any of the other balloon soundings this morning at adjacent islands (Barbados, Puerto Rico, Saint Martin), and demonstrates that there is a lot going on the atmosphere at small scales we cannot see which makes intensity forecasting of tropical cyclones very challenging. Thanks go to Jason Dunion of NOAA's Hurricane Research Division for pointing out this morning's interesting Guadaloupe sounding.

Forecast for Chantal
Chantal will have difficulty intensifying much more before hitting Hispaniola on Wednesday afternoon. In their 11 am EDT wind probability forecast, NHC gave Chantal a 29% chance of becoming a hurricane before hitting Hispaniola. Working against intensification will be the high wind shear from the strong mid-level easterly jet discussed above, plus the fast forward speed of the storm--tropical storms moving faster than 20 mph in the deep tropics usually have trouble intensifying. In addition, the Eastern Caribbean is an area where the trade winds accelerate, helping drive sinking air that discourages tropical storm intensification. Dry air will also slow down the intensification process. Interaction with the high mountains of Hispaniola and high wind shear may be able to destroy Chantal by Thursday. The 2 pm EDT Tuesday wind shear forecast from the SHIPS model calls for shear to rise to the high range, 20 - 35 knots, Tuesday night through Friday. On Saturday, when Chantal is expected to be in the Bahamas, moderate wind shear of 10 - 20 knots is predicted. If Chantal survives until Saturday, it will then have the opportunity to re-strengthen. The latest 12Z run of the European model (ECMWF) dissipates Chantal as it crosses Hispaniola. The 12Z run of the American GFS model has Chantal barely surviving.

Chantal's fast west-northwest forward speed of 26 mph will slow to 20 mph by Wednesday morning and then 10 mph by Thursday night, as the storm "feels" the presence of a trough of low pressure over the U.S. East Coast. This trough will steer Chantal to the northwest and then north-northwest across Hispaniola and into the Bahamas. The trough of low pressure pulling Chantal northwards is expected to lift out the the northeast over the weekend, leaving Chantal behind off the coast of Florida. High pressure will likely build in, potentially forcing Chantal westwards into the Florida or Southeast U.S. coast, with a possible Sunday landfall.

Jeff Masters

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Quoting 1884. lobdelse81:
Any word on that tropical wave that came off Africa? Is it still possible that this wave could perform better than Chantal as she probably moistened and paved the way for a better environment for this wave to develop?


Dry air didn't kill Chantal. Low-level speed shear did.
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Chantal looks like a bomb got dropped on her and her convection, structure, and everything resembling a TS got vaporized. She's as dead as dead gets it's looking. Hard to see her ever coming back from this.
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Any word on that tropical wave that came off Africa? Is it still possible that this wave could perform better than Chantal as she probably moistened and paved the way for a better environment for this wave to develop?
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Quoting 1878. AussieStorm:
Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 10th day of the month at 06:32Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 301)
Storm Number: 03
Storm Name: Chantal (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 04

Mandatory Data...

Observation Time: Wednesday, 6:22Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 16.1N 67.2W
Location: 177 miles (284 km) to the SSW (205°) from San Juan, Puerto Rico (USA).
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 1,530 meters
Flight Level Wind: From 150° at 39 knots (From the SSE at ~ 44.8 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 17°C
Flight Level Dew Point: 17°C
Weather (within 30 nautical miles): Unknown, either due to darkness or some other cause
850 mb Surface Altitude: 1,580 geopotential meters

Remarks Section...

Surface Wind Speed (likely by SFMR): 26 knots (~ 29.9mph)
Mission Status: Concluded (Last Report)


Hmmm...29 mph not looking too good right now.
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1882. sar2401
Quoting Tribucanes:




Sar always such the sarcastic contrarian. You wouldn't be you if your weren't though. Chantal's death mask hasn't been secured just yet. While your logic is good and your most likely right here, Chantal could find life again. If she's dead and only a wave that is. Gotta be virtually no chance she still a TS though based on imagining. Should change your name to WishcastingdreamCrusher. Pretty amazing story you dropped last night about your fateful avoidance of being caught out in the open seas in a sailboat in the face of a Cat.5.

Yeah, well, I'm only a oontrarian (and sometimes sarcastic) when I don't see evidence to support things like models wanting to put 987 mb hurricanes over Florida in five days for a 1011 weak TS. I'm not ready to write off Chantal yet, since I'm not smart enough to know what will really happen, but the probability of Chantal getting any bigger than what she has already been is dropping by the hour. OTOH, we tend to "what if" ourselves to death on the blog. What if Chantal got caught up in that ULL low (which isn't doing anything it was supposed to), what if Chantal could follow an Ivan path into the Gulf....what if...what if. There are a lot of things that might happen, but there are only a few things that are likely to happen. Believe me, when I see a storm that's likely to be bad, I'll be right among all the other panic forecasters but, this early into the season, I certainly lean toward downcasting until there's evidence to the contrary. However, when I see a continual line of drivel from people who joined two days ago about what Chantal was gong to do, that made me even more skeptical that Chantal wasn't going to be "the Storm of the Century".

Indeed, Ivan taught me that hurricanes can do things they've never done before, and I would be dead today if I was on my boat and followed the conventional hurricane logic. It's not that it was ever impossible that Chantal could have become a significant hurricane, it just wasn't likely. I will always err on the side of likely compared to "what if". :-)
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The NHC isn't apt to terminate systems at night, but in this particular instance I think they will.
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No way this is cyclone at 5 am. Night.
Member Since: August 1, 2011 Posts: 28 Comments: 8030
Quoting 1877. allancalderini:
Nights everyone-


Night Allan. :)
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Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 10th day of the month at 06:32Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 301)
Storm Number: 03
Storm Name: Chantal (flight in the North Atlantic basin)
Mission Number: 4
Observation Number: 04

Mandatory Data...

Observation Time: Wednesday, 6:22Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 16.1N 67.2W
Location: 177 miles (284 km) to the SSW (205°) from San Juan, Puerto Rico (USA).
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 1,530 meters
Flight Level Wind: From 150° at 39 knots (From the SSE at ~ 44.8 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 17°C
Flight Level Dew Point: 17°C
Weather (within 30 nautical miles): Unknown, either due to darkness or some other cause
850 mb Surface Altitude: 1,580 geopotential meters

Remarks Section...

Surface Wind Speed (likely by SFMR): 26 knots (~ 29.9mph)
Mission Status: Concluded (Last Report)
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Nights everyone-
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Quoting 1744. GTstormChaserCaleb:
The CMC hasn't given up yet.



I think that is where the GEM had it about 1 week ago....Consistent at least
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Quoting 1872. CaicosRetiredSailor:
Try this for 05:45 UTC




that is pathetic to say the least.
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Quoting 1856. sar2401:

No, it won't. 94L had an entire week in the Gulf, when conditions were much better, and it never become more than an invest.

If I may correct you the trough was still in place over TX and shear was still pretty high. KFDM 6 confirmed that and so did the NWS.
Member Since: September 2, 2011 Posts: 0 Comments: 1148
Try this for 05:45 UTC




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Quoting 1867. CaicosRetiredSailor:
Interesting, when I first posted the loop in #1852 it ran until 5:45 UTC as seen below:



[edit]
Aaaaaaaargghh!
now this is fetching an earlier plot.

Itsa conspiracy!


I'm with you: Major conspiracy!

We demand the original images back now

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Quoting 1863. ackee:
I am surprise the wave in the eastern Atlantic has been painted yellow by the NHC as yet. chantal is Rip she really bought a lot of drama tracking her just my view
maybe they will mention it on the 8am two at least thats my prediction if im wrong so be it.
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Quoting 1866. cwf1069:
Plane is living. No coc. Chantal for now is dead. Let see what tomorrow bring with it.
Good Night everybody.


Tomorrow's not going to bring anything. Deceleration isn't going to help its chances after 500 mg of westerly shear and Hispaniola.

The real fun begins later on.
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Quoting 1861. sar2401:

What's more interesting to me is that, except for the data from the Hurricane Hunters, Chantal probably would have become a hurricane, based on satellite presentation and Dvorak numbers. I wonder how many other Chantals were out there in the days before Hurricane Hunters were able to provide the kind of real-time data they do today.
I am still skeptical about the 1914 season only having one storm and a TD. There just had to be more storms way out in the Atlantic.
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Interesting, when I first posted the loop in #1852 it ran until 5:45 UTC as seen below:



[edit]
Aaaaaaaargghh!
now this is fetching an earlier plot.

Itsa conspiracy!
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1866. cwf1069
Plane is living. No coc. Chantal for now is dead. Let see what tomorrow bring with it.
Good Night everybody.
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1865. sar2401
Quoting Camille33:

Is it me or r u wishing for storms? We need don't want to provoke storms by wanting them.

It's you. He made a simple statement that Chantal being able to develop as TS so far south has only happened a few times in modern history. It seems to me from some of your posts that you are the one who's doomcasting stoms, not people like GT. Finally, I don't think any of us have the ability to "provoke" a storm.
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Quoting 1851. sar2401:

It's really hard to face reality when you've been forecasting (wanting) something else. There's nothing in the Gulf to make it go "BAM", assuming Chantal makes it there as anything more than a remnant low. Water temperatures are cooler than average courtesy of last blob that sucked water and energy out of the Gulf or the past week. The trade winds are blowing, there's lots of dry air about, and wind shear is still high enough to disrupt anything as weak as ex-Chantal. Juat watch what happens over the next two days and learn something about waves that come out of 9N and don't develop before they hit 15N while traveling at the speed of an aircraft carrier.




Sar always such the sarcastic contrarian. You wouldn't be you if your weren't though. Chantal's death mask hasn't been secured just yet. While your logic is good and your most likely right here, Chantal could find life again. If she's dead and only a wave that is. Gotta be virtually no chance she still a TS though based on imagining. Should change your name to WishcastingdreamCrusher. Pretty amazing story you dropped last night about your fateful avoidance of being caught out in the open seas in a sailboat in the face of a Cat.5.
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1863. ackee
I am surprise the wave in the eastern Atlantic has been painted yellow by the NHC as yet. chantal is Rip she really bought a lot of drama tracking her just my view
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Quoting 1860. AtHomeInTX:


And Texas wouldn't be in drought anymore. LOL!


And I would've gotten my Gustav redux! :P
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1861. sar2401
Quoting GTstormChaserCaleb:
Once last thing considering how early it is still in the season, for Chantal to develop where she did and make it into the Caribbean is impressive in its own, so regardless of what happens here on out, not bad.

What's more interesting to me is that, except for the data from the Hurricane Hunters, Chantal probably would have become a hurricane, based on satellite presentation and Dvorak numbers. I wonder how many other Chantals were out there in the days before Hurricane Hunters were able to provide the kind of real-time data they do today.
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Quoting 1859. KoritheMan:


Provoke storms? lolwut? They don't have a mind of their own, or else JFV would have flattened Miami by now. :)


And Texas wouldn't be in drought anymore. LOL!
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Quoting 1858. Camille33:

Is it me or r u wishing for storms? We need don't want to provoke storms by wanting them.


Provoke storms? lolwut? They don't have a mind of their own, or else JFV would have flattened Miami by now. :)
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Quoting 1855. GTstormChaserCaleb:
Once last thing considering how early it is still in the season, for Chantal to develop where she did and make it into the Caribbean is impressive in its own, so regardless of what happens here on out, not bad.

Is it me or r u wishing for storms? We need don't want to provoke storms by wanting them.
Member Since: July 2, 2013 Posts: 0 Comments: 1521
Quoting 1855. GTstormChaserCaleb:
Once last thing considering how early it is still in the season, for Chantal to develop where she did and make it into the Caribbean is impressive in its own, so regardless of what happens here on out, not bad.


True. Night Caleb. Rest up. :)
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1856. sar2401
Quoting Stormchaser121:

If it does that it WILL restrengthen.

No, it won't. 94L had an entire week in the Gulf, when conditions were much better, and it never become more than an invest.
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Once last thing considering how early it is still in the season, for Chantal to develop where she did and make it into the Caribbean is impressive in its own, so regardless of what happens here on out, not bad.
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1853. sar2401
Quoting GTstormChaserCaleb:
Calling it a night, just thinking there will be more nights like this in the coming weeks, so best I save my energy. You guys sleep well.

GN, GT. The nights will come soon enough when there are real storms and real lives at stake.
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1851. sar2401
Quoting Stormchaser121:
If at the 2am advisory Chantal is still a TS...im not giving up on it. Even after that im not giving up because once she gets past the shear...possibly into the Gulf...BAM she will come back.

It's really hard to face reality when you've been forecasting (wanting) something else. There's nothing in the Gulf to make it go "BAM", assuming Chantal makes it there as anything more than a remnant low. Water temperatures are cooler than average courtesy of last blob that sucked water and energy out of the Gulf or the past week. The trade winds are blowing, there's lots of dry air about, and wind shear is still high enough to disrupt anything as weak as ex-Chantal. Juat watch what happens over the next two days and learn something about waves that come out of 9N and don't develop before they hit 15N while traveling at the speed of an aircraft carrier.
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Calling it a night, just thinking there will be more nights like this in the coming weeks, so best I save my energy. You guys sleep well.
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because of Chantal's weak state I think she will continue to move W and will be too weak to move WNW much less NW out of the Caribbean
Member Since: June 13, 2009 Posts: 2 Comments: 12163
NWS San Juan ‏@NWSSanJuan 4m
#Chantal 2 AM Location 15.5 N 68.0 W Maximum sustained winds 50 mph. Moving W at 30 mph

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Quoting 1843. GTstormChaserCaleb:
NOGAPS brings Chantal into the Gulf, very weak.


If it does that it WILL restrengthen.
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Quoting 1834. 7544:
hmmm is this new

Link


Looks a lot like the 12z GFS track anyway.
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@Ameister12 & Aussie
Nice pics and loop there of Soulik, beautiful storm, unlike someone I know.

1:15 AM here, I have senior portraits tomorrow, night WU.
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well i guess the nhc didnt mention the african wave on the 2am two
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NOGAPS brings Chantal into the Gulf, very weak.

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1842. hu2007
good night everyone and nice links and useful informacion i will keep in touch about the next system that forms bye
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Typhoon Soulik True Colour



Inside the eye.

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1839. 7544
idk reforms it?

Link
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Quoting 1834. 7544:
hmmm is this new

Link
Yes that is the latest GGEM or CMC as you can see it wants to redevelop Chantal south of Central Cuba. We will see if there is anything left to track at that point.
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1837. hu2007
Quoting 1828. sar2401:

Maybe if Chantal was a cat but, as a tropical storm, she has just about run out of gas.
right :D
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I say dead, but looking on the shortwave IR channel 2 imagery, I can see some spin around 16N 58W, you have to really slow it down and look close. And there is some moderate (albeit sheared) thunderstorm activity in that general area. But low level winds do not support closed LLC. Perhaps mid levels? IDK.
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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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