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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2086. gator23
oh. Is that where you live? Do you want this storm? I find that people's forecast track is often influenced by where they live. It just doesnt seem likely has Texas would be a 1000 plus mile swing which usually never happens

Quoting 2075. Stormchaser121:

Well...I do mean Texas.
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Quoting 2084. indianrivguy:


please speak for yourself, and not for all Floridians...not everyone, including me agrees with this statement. Given that they are dumping more than two BILLION gallons a day of polluted water into Indian River lagoon, and the St. Lucie estuary, we along southern Indian River don't need, nor want any tropical system to add water to any watershed south of Orlando.


yeah, same here in northern Georgia, we don't need rain at all
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Quoting 1999. jeffreeysweetypie:
Here in florida we would rather have chantal then our daily afternoon t storms.... our t storms are so much worse then what chantal will bring


please speak for yourself, and not for all Floridians...not everyone, including me agrees with this statement. Given that they are dumping more than two BILLION gallons a day of polluted water into Indian River lagoon, and the St. Lucie estuary, we along southern Indian River don't need, nor want any tropical system to add water to any watershed south of Orlando.
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2083. Grothar
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2082. KEEPEROFTHEGATE (Mod)
Quoting 2073. IKE:
41m
Chantal became an open wave yesterday as per ideas. NHC holding on to a ghost.NHC will downgrade soon
nice to see ya ike
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2081. MahFL
Quoting 2026. jeffreeysweetypie:
moving 29mph , lots of mountains to go over tons of dry air....... R.I.P. chantal


What dry air, north of Chantal is moist, cept a tiny spot near NE FL.
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Quoting 2068. bigwes6844:
Thats the one! I saw the Typhoon pass almost right over it!


well that island go the very highest destructive power from this typhoon... such a great looking storm that is
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Will need a few frames to really tell what she's up to.

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11:08:00Z 17.867N 67.767W

Recon on the way
Member Since: August 19, 2005 Posts: 5 Comments: 5449
Quoting 2073. IKE:
41m
Chantal became an open wave yesterday as per ideas. NHC holding on to a ghost.NHC will downgrade soon


Hmmm.. I see

just like crappy Emily 2011
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Quoting 2065. KORBIN:
Up the west coast of Florida on a similar path would be much scarier if she developed. Since the majority of a storms strength is in the NE Quad.
Yes, but from a $ and population standpoint...more expensive real estate and people along the east coast of Florida. Could easily be the most expensive storm ever. I should say a major skirting the east coast with the eye wall.
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Quoting 2070. gator23:
Agreed, Freeport Bahamas looks like. Unless you mean Texas in which case no.


Well...I do mean Texas.
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Speaking objectively, I guess if there is no closed LLC to disrupt the mountains will not be as much of an issue?
Member Since: August 19, 2005 Posts: 5 Comments: 5449
2073. IKE
41m
Chantal became an open wave yesterday as per ideas. NHC holding on to a ghost.NHC will downgrade soon
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Quoting 2066. GeoffreyWPB:
Quite surprised when I read the 5am NHC Discussion a few moments ago...

Look at those trade winds! She better put on her wipers or they will wipe her off
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Quoting 2057. CycloneOz:
The ULL is the key to Chantal's track. Keep an eye on it.

Nice!
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2070. gator23
Agreed, Freeport Bahamas looks like. Unless you mean Texas in which case no.

Quoting 1996. Stormchaser121:

I'm still saying freeport.
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2069. KEEPEROFTHEGATE (Mod)
Quoting 2064. stormpetrol:


According to this there is no closed circulation.
she's open may be 12 to 18 hrs before closing off again if she can even do it
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Quoting 2062. AussieStorm:

That is....
Okinotori Islands


Japan Meteorological Agency Okinotori-shima Islands Observatory,Okinotori-shima Islands





I wonder if they evacuated?
Thats the one! I saw the Typhoon pass almost right over it!
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Quoting 2059. ProgressivePulse:
I bet you Chantal decoupled last night looking at satellite. It's the secondary area that we observed last night around 16.2 that is firing convection this morning. I bet the area at 14.9 is the dying MLC

If she's going to make it then she'll have to reform center in the northern part of this, perhaps around 17. The coastline curve may help plus there is shear out front to slow her down. who knows, just speculating on survival scenarios

actually, looking at dvorak white spots that is currently what's happening on a microlevel.
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Quite surprised when I read the 5am NHC Discussion a few moments ago...

Member Since: September 10, 2007 Posts: 0 Comments: 11259
2065. KORBIN
Up the west coast of Florida on a similar path would be much scarier if she developed. Since the majority of a storms strength is in the NE Quad.
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According to this there is no closed circulation.
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I knew...I KNEW Chantal wasnt gonna die. I havent had a feeling about a storm like this since Ike. Idk how i knew it but I KNEW Ike was gonna hit TX. Freeport is still my prediction for Chantal. That Bermuda high and the ULL I believe will push it west rather than north.
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Quoting bigwes6844:
See da dot it passed by dats that i was tryna figure out what was dat?

That is....
Okinotori Islands


Japan Meteorological Agency Okinotori-shima Islands Observatory,Okinotori-shima Islands





I wonder if they evacuated?
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This is yet to come.
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Quoting 2056. unknowncomic:
This is a nightmare path for Florida if it were a Major storm.





Not to contradict, but an obtuse angle like that would be far preferable than head-on.

Time for me & Dexter to take a walk. See y'all in a bit (with the GM pic, don't tell Taz, shhhhhh)...
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I bet you Chantal decoupled last night looking at satellite. It's the secondary area that we observed last night around 16.2 that is firing convection this morning. I bet the area at 14.9 is the dying MLC
Member Since: August 19, 2005 Posts: 5 Comments: 5449
Quoting 2056. unknowncomic:
This is a nightmare path for Florida if it were a Major storm.





Actually, that 12+ hr stint in GA would be a nightmare for parts of GA and the Carolinas...Have already had copious amounts of rain and rivers have been running high.
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The ULL is the key to Chantal's track. Keep an eye on it.

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This is a nightmare path for Florida if it were a Major storm.



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Quoting 2051. stormwatcherCI:
She seems once again to be trying to make a comeback. Firing convection again.

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3/4" of rain last night at about 4am. This makes the biggest rain event here since June 1st. Data available at Rainlog.org (scroll map over to Lantana, FL - click on the gauge reading).


Quoting 2036. trunkmonkey:


I need a case of repellent, where can I get some????


There's several brands available...





Check your local Web Supply store...
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Quoting 2042. ProgressivePulse:
I saw the prior satellite frames for Chantal, ugly. Good thing I chose not to stay up later. Once she lost the red ball last night I knew she was going to have a rough ride for a while.


Morning all

Yep, just a couple hours ago she looked pretty rough. Looks a little more healthy now, but still not a pretty woman by any means.

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24 west!
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Quoting 2048. ProgressivePulse:


I hope so. The prior convection free satellite frames and corresponding death call from the NHC was rather depressing this morning.
She seems once again to be trying to make a comeback. Firing convection again.
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wishing chantel got beaten looks like she is in for the long haul.
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watching 24 west nice red is round..
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Quoting 2046. stormwatcherCI:
Good morning. Recon seem to be on their way again.


I hope so. The prior convection free satellite frames and corresponding death call from the NHC was rather depressing this morning.
Member Since: August 19, 2005 Posts: 5 Comments: 5449
2047. KEEPEROFTHEGATE (Mod)
Quoting 2044. Chicklit:
The shear out in front of the storm is not friendly.


but to the north its sayin come on over for a BBQ
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Good morning. Recon seem to be on their way again.
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2045. WxLogic
Quoting 2041. KEEPEROFTHEGATE:


may track a little to the right of current projections
cross the narrow end of east cuba
enter the sw atlantic
to the left of the passage

once there RI may occur in less than 6 hrs



Quite possible.
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The shear out in front of the storm is not friendly.

I don't see how she makes it west through that; much better to reform her center and go north of course through the Windward Passage.
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Quoting 2021. BahaHurican:
Good morning all.

I have to say I had no intention of being awake at this hour... lol... however the thunder woke me up. Seems the western edge of the ULL is kicking up a storm or two.

I think this ULL has been a kink in the NHC forecast, since its behaviour has been more difficult to forecast than Chantal's the last couple of days. I expected it would have scooted over into the GoM by now, but it seems it will be still drifting over the Keys tomorrow.

Furthermore, instead of Chantal slowing down, I see it has sped up! No wonder it's the next best thing to an open wave. And with the high as strong as it is, it's starting to look like Chantal may be a Brownsville darling after all.

We'll see if Chantal falls in behind the upper trough and turns up along the FL coast. That GA landfall is unusual, even in a forecast. I gotta say, just about the only place that is more overdue for a landfalling storm than FL is GA... be interesting if Chantal does end up there, and then sets a trend for landfall in that area...



I Doubt it....but we'll see... this very may well come ashore in GA but i doubt it sets the trend....but you never know
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I saw the prior satellite frames for Chantal, ugly. Good thing I chose not to stay up later. Once she lost the red ball last night I knew she was going to have a rough ride for a while.
Member Since: August 19, 2005 Posts: 5 Comments: 5449
2041. KEEPEROFTHEGATE (Mod)
Quoting 2031. ProgressivePulse:
Chantal wanted to go over the less mountainous Central Cuba. Seems to be "trying" to make another comeback this morning. She's down but I sure wouldn't count her out. She is a tenacious little "B" and conditions could become very favorable once north of Cuba.



may track a little to the right of current projections
cross the narrow end of east cuba
enter the sw atlantic
to the left of the passage

once there RI may occur in less than 6 hrs

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GFS Ensemble consensus, if there is rain on the north side of the remnants of Chantal, might not be good for N GA



Fortunately I'm not in N GA

The other models may be trying to move Chantal more west though, (unless this is a mistake)




After talking to Dr. Louis Ucellini yesterday, we're going to NCEP today along with UMD.

Should be gone all day, so have a good day everybody.
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Quoting 2027. StormTrackerScott:
Folks don't count Chantal out yet as there is almost no shear close to fl. Chantal has been fighting some westerly shear the last 24 hours but once Chantal emerges in the sw Atlantic then conditions will be very favorable for regeneration.


What a journey for Chantal. Thankfully she may not become the threat she once posed to the SE USA but this speaks for the rest of the season. Florida may be in in deeply.
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2038. WxLogic
Quoting 2027. StormTrackerScott:
Folks don't count Chantal out yet as there is almost no shear close to fl. Chantal has been fighting some westerly shear the last 24 hours but once Chantal emerges in the sw Atlantic then conditions will be very favorable for regeneration.


For now HWRF & GFDL are calling for it. Interesting enough most models never really intensified Chantal enough in the Caribbean, but they sure did love the conditions once it goes into the Bahamas.

We'll see the evolution of it in the next couple of days. I do believe that Chantal or her remnants will have less interaction with Hispaniola than previously forecasted and therefore more changes to hold her self together.
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2037. vis0
Quoting 1954. bigwes6844:
DR must be cooking some fresh breakfast LOL! thats probably y we see this burst. could be orange juice?


Dr. Master's Rhubarb pie ...strawberry?!, ... mmm
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Quoting 2024. StormTrackerScott:
It's too early in the am for trolls. May have to get some troll repellent if this keeps up.


I need a case of repellent, where can I get some????
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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.