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 79. TropicalAnalystwx13:

If by developing an eye you mean developing a dry spot from recently-collapsed thunderstorms, then yes, I guess it is developing an "eye".

If you mean the clear spot at the center of a tropical cyclone with deep thunderstorm activity surrounding it, then you would be incorrect.

Amen.
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Quoting 24. Envoirment:
Re-posting this to confirm there is no eye formation in Chantal. Taken at 19:45 UTC



Compare that to Soulik



;)

Chantal looks more like a highly vigorous tropical wave that just so happens to be speeding along at nearly 30mph. Theoretically a vigorous tropical wave could produce 30mph easterly winds of its own. Add that to its forward speed and you would have one strange storm!
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Quoting 64. Gearsts:
By spamming?


Eh.. yeah you have a point there.. And back to the storm; diddn't the models show Irene plowing into Florida, then South Carolina, and then finally the obx? Chantels really taking on a similar track to that lovable "I" storm in my opinion.. if i remember correctly Irene took awile to get her act together as well?
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Quoting 74. SecretStormNerd:


It would seem youre trolling. Unless you like making the same comment 60 times in one day? All of the models have said Florida for days. I'm sorry this makes you sad. Get over it.
Green Acres is the place to be...Farm livin' is the life for me....Boynton here
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Quoting 75. whitewabit:
During name storms .. keep comments on about the storm or the topic of Dr Msters Blog .. adhere to the Rules of the Road ..

Other off topic comments will not be tolerated ..

It would be a shame for a blogger to be unable to post during a storm ..



How sad! Is there any bloggers that are currently banned?
Member Since: June 14, 2013 Posts: 2 Comments: 1734
Quoting 71. CaribBoy:
12Z GFS .... no Dorian in the MDR, it shows a fish.
the 12z run was scrwed up, wait for the 18z
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Quoting 69. stormpetrol:
Chantal cruising along the 15N Latitude line for now, appears to be developing an eye too.

If by developing an eye you mean developing a dry spot from recently-collapsed thunderstorms, then yes, I guess it is developing an "eye".

If you mean an eye as in the clear spot at the center of a strong tropical cyclone with deep thunderstorm activity surrounding it, then you would be incorrect.
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Quoting 71. CaribBoy:
12Z GFS .... no Dorian in the MDR, it shows a fish.

Its only shown that solution once. Wait for more consistency first.
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Too far north too far south... I'm tired with that.
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Quoting 71. CaribBoy:
12Z GFS .... no Dorian in the MDR, it shows a fish.




what are you smokeing nothing is going out too sea with that strong high we have
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75. whitewabit (Mod)
During name storms .. keep comments on about the storm or the topic of Dr Masters Blog .. adhere to the Rules of the Road ..

Other off topic comments will not be tolerated ..

It would be a shame for a blogger to be unable to post during a storm ..


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Quoting 67. jeffreeysweetypie:
looking at the models its further west and south and staying over alot more land then they said yesterday.... so it might even fall apart in 3 days


It would seem youre trolling. Unless you like making the same comment 60 times in one day? All of the models have said Florida for days. I'm sorry this makes you sad. Get over it.
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Shame on You Chantal, Shame on you ! NOTHING for us in the northern leewards islands !
I'm pretty sure that carib boy will understand me!
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Link
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12Z GFS .... no Dorian in the MDR, it shows a fish.
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That wave off Africa already has nice cyclonic turning.Get ready to start turning heads soon further east.
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Chantal cruising along the 15N Latitude line for now, appears to be developing an eye too.
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Quoting Envoirment:


Thankfully not! Soulik is large enough to cover the entire Caribbean and would cause total devistation.

Although, there may be some very strong and large hurricanes to come later in the season as it is still early days for the Atlantic. Hopefully most will go out to sea, but given the current set up, that seems very unlikely.

Gilbert was a pretty large storm from start to finish. I think that it was in excess of 500 miles across...It covered a large part of the Caribbean.
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By CARLISLE JNO BAPTISTE — Associated Press

ROSEAU, DOMINICA — Tropical Storm Chantal raced across small islands in the eastern Caribbean on Tuesday as officials issued a hurricane watch for the southern coast of the Dominican Republic.

The storm was centered about 335 miles (540 kilometers) southeast of Puerto Rico around 2 p.m. EDT Tuesday, the U.S. National Hurricane Center in Miami said. The storm had maximum sustained winds of 65 mph (100 kph), and was moving west-northwest at 29 mph (46 kph).

Officials in Dominica reported that heavy winds ripped off the roofs of several homes. But no injuries were reported in Dominica, or anywhere else in the region.

"It's getting rough out there," said Conrad Ceasar, an emergency management official for Dominica's southern region. "Some parts of the island are without electricity."

The government cancelled the country's ferry service and closed airports, and National Security Minister Charles Savarin said government offices would close at noon. "Chantal is a serious storm," he said.
...

Read more here: http://www.newsobserver.com/2013/07/09/3018639/tro pical-storm-chantal-heading.html#storylink=cpy

Member Since: July 12, 2007 Posts: 0 Comments: 6067
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Quoting 61. HurricaneWeatherDan:
People need to calm down about the count downs, its kind of been a slow couple of hours, so who cares if they wanna kill some time
By spamming?
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Quoting 45. GTstormChaserCaleb:
Umm the whole count down thing is really unnecessary and a waste of blog space, it is like spamming. Please stop. Thanks

It is spamming and I just "-" and "!" those posts. Those options are there for a reason.
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...TROPICAL WAVES...
TROPICAL WAVE IS ANALYZED ALONG 18W FROM 8N-18N DRIFTING W. WAVE
IS EMBEDDED WITHIN A SURGE OF DEEP MOISTURE AS DEPICTED ON THE
TOTAL PRECIPITABLE WATER IMAGERY. A MID LEVEL CYCLONIC ROTATION
IS NEAR THE BASE OF THE TROPICAL WAVE. NO ASSOCIATED DEEP
CONVECTION.
Member Since: March 12, 2013 Posts: 54 Comments: 84421
People need to calm down about the count downs, its kind of been a slow couple of hours, so who cares if they wanna kill some time
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I'm already more excited for Dorian lol going out now to get spaghetti o's (organic of course) and some water just in case it decides to get here as a hurricane
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Quoting 31. GTstormChaserCaleb:
At least we have 2 storms going on at the same time to compare. Thankfully Soulik is not the one in the Eastern Caribbean or we would be talking BIG problems.


Thankfully not! Soulik is large enough to cover the entire Caribbean and would cause total devistation.

Although, there may be some very strong and large hurricanes to come later in the season as it is still early days for the Atlantic. Hopefully most will go out to sea, but given the current set up, that seems very unlikely.
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Quoting 56. PalmBeachWeather:
GT.I think it's an attempt to raise their comments the easy way...

We have stopped.
Member Since: June 14, 2013 Posts: 2 Comments: 1734
Quoting 45. GTstormChaserCaleb:
Umm the whole count down thing is really unnecessary and a waste of blog space, it is like spamming. Please stop. Thanks
GT.I think it's an attempt to raise their comments the easy way...
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55. whitewabit (Mod)
Quoting 51. islander101010:
heard stories about birds that get caught in the eye of these monsters and fly whereever it goes. is this a fallacy?


no during the eye of Camille there were hundreds of birds flying in the eye ..
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Quoting 44. Thrawst:
40 something minutes until I ignore every one of you that says how many minutes until the next advisory, every minute.
Why wait? LOL
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Quoting 49. Tazmanian:
i think this will be come 96L soon



It will be as soon as the wave axis exits and it starts to consolidate.
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..
Member Since: June 14, 2013 Posts: 2 Comments: 1734
heard stories about birds that get caught in the eye of these monsters and fly whereever it goes. is this a fallacy?
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.
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i think this will be come 96L soon


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Quoting 29. weatherh98:
my 7 day forecast for Chantal


EVEN after the models long term shifted eastward towards SC and GA.. not making just a hard left?
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Ok, we will stop, it never was a good idea.
Member Since: June 14, 2013 Posts: 2 Comments: 1734
Umm the whole count down thing is really unnecessary and a waste of blog space, it is like spamming. Please stop. Thanks
Member Since: June 30, 2013 Posts: 12 Comments: 8706
40 something minutes until I ignore every one of you that says how many minutes until the next advisory, every minute.
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Thanks Dr Masters...It seems as if was a bit of Damage in Dominica. Is SLU around? Maybe he'll be able to give us an update on Chantal's impact on St Lucia.
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Quoting 36. 62901IL:
44 minutes!!!!!!!!!!!!

We all know what time the next National Hurricane Center advisory comes out. Please stop spamming the blog with worthless posts. Dang.
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nice tropical wave to watch
Member Since: March 12, 2013 Posts: 54 Comments: 84421
Would be nice if RAMSDIS repositioned their floater.
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Quoting 34. weatherh98:
I don't even understand how you could think that's an eye....
they just confirmed No eye.
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Wow, people are seriously taking the joke abouth eye forming... it was a satellite mistake. It's a joke.
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Dang Doc.Slow ya row.0
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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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