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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1986. GetReal
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Quoting 1982. GetReal:



This brings new meaning to on life support!
LOL! Looked like the trade winds punched chantal right in the face on this image!
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Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting 1978. Kumo:


Wave heights must have been insane, any fish in the area would have been in for one heck of a ride.
try over 30 ft straight washed out!
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1982. GetReal



This brings new meaning to on life support and last gasp!
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Looks interesting,expect to be a new AOI and invest.
Member Since: June 11, 2013 Posts: 20 Comments: 2968
Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting 1975. mikatnight:


Ah, I guess I misunderstood your statement. Just wanted to make sure I wasn't supposed to be ticked-off at Wake for some reason.
LOL!!
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1978. Kumo
Quoting 1960. bigwes6844:
Whatever it is probably is destroyed big time! The eye went almost over it


Wave heights must have been insane, any fish in the area would have been in for one heck of a ride.
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Quoting 1970. Kumo:


Nope, Wake is even further out in the Pacific, about halfway between Taiwan and Hawaii. Southeast of Japan.

The little submerged atoll/reef Soulik passed over is about halfway between Guam and Naha. South of Japan.
k i couldnt find it on the map though
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Member Since: June 11, 2013 Posts: 20 Comments: 2968
Quoting 1972. bigwes6844:
Typhoon Soulki passed over it


Ah, I guess I misunderstood your statement. Just wanted to make sure I wasn't supposed to be ticked-off at Wake for some reason.
Member Since: October 18, 2005 Posts: 4 Comments: 3052
See da dot it passed by dats what i was tryna figure out what was dat?
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Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting 1967. mikatnight:
Mornin' BigWes -

Just curious...what's the beef with Wake Island?
Typhoon Soulik passed over it
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If the 'pink tongue of death' moves left again it'll be over our house.

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1970. Kumo
Quoting 1962. bigwes6844:
Its called wake Island That place should be destroyed



Nope, Wake is even further out in the Pacific, about halfway between Taiwan and Hawaii. Southeast of Japan.

The little submerged atoll/reef Soulik passed over is about halfway between Guam and Naha. South of Japan.
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Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting 1962. bigwes6844:
Its called wake Island That place should be destroyed



Snap! well yeah, whatever it's called, anything that was there may not be now
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Mornin' BigWes -

Just curious...what's the beef with Wake Island?
Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting 1930. bigwes6844:
anybody sees that dot where Soulik passed over? What island is that?


Looks like it's Okinotori-shima looking at the map. Dunno if anything there, looks like a very shallow/below sea level atoll
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1965. emguy
For the record...not a research station...and not just some little island named Wake Island...The place is a WW2 battle site.
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The Hurricane



Some little cloud off the African coast
Crosses the ocean and sometimes it grows.
Forecasters spin it around,
Newscasters stake out the ground
Where they think the cone of death is pointing.

Andrew and Wilma and Frances and Jeanne,
Some of the worst storms South Florida's seen.
What have we learned from them?
We've blown 'em off again and again and again and again and again.

This is the season of the hurricane,
The time of year when they use the name
Of storms we pray won't come,
'Cause if they do we either run,
Hunker down, or batten all the hatches.

The constant battle against apathy,
'Cause most of us think, well, it won't hit me,
But all those in the know
Say that anything goes
And it only takes one storm to blow us all away.

So, stock up on bottled water, batteries too,
Get lots of plywood and drills and screws,
Because you never know
When those summer winds may go
And huff and puff and blow your house down.

This is the season of the hurricane,
The time of year when they use the name
Of storms we pray won't come,
'Cause if they do we either run,
Hunker down, or batten all the hatches.
Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting 1958. Kumo:


Not sure but it looks like an submerged atoll that belongs to the Japanese. You can zoom into it on Google maps. There are some odd looking structures in the lagoon, I am thinking it might be some kind of research station.
Its called wake Island That place should be destroyed

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Weeeeelp

That sat floater is completely broken.


I am going to bed now. Bye.

10 bucks says open wave later.
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Quoting 1958. Kumo:


Not sure but it looks like an submerged atoll that belongs to the Japanese. You can zoom into it on Google maps. There are some odd looking structures in the lagoon, I am thinking it might be some kind of research station.
Whatever it is probably is destroyed big time! The eye went almost over it
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1958. Kumo
Quoting 1930. bigwes6844:
anybody sees that dot where Soulik passed over? What island is that?


Not sure but it looks like an submerged atoll that belongs to the Japanese. You can zoom into it on Google maps. There are some odd looking structures in the lagoon, I am thinking it might be some kind of research station.
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Good morning Chantal
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Quoting 1952. Stormchaser121:

The smell of Bacon and Waffles woke her up! haha
DR must be cooking some fresh breakfast LOL! thats probably y we see this burst. could be orange juice?
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Quoting 1949. DataNerd:
Huh. The sattilite page just screwed itself up.

Now its showing nothing there and is stuck without the most recent imagery. Any of the loops drop back to 1 hour old imagery instead of the new shots.



Bizzare. Well lets see what it looks like after this issue is fixed.
yeah i know it did that to me about an hour ago. something must be wrong
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Quoting 1951. bigwes6844:
maybe she finally woke up it is almost 5 am. its her breakfast time lol

The smell of Bacon and Waffles woke her up! haha
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Quoting 1946. Stormchaser121:
Welcome back Chantal!
maybe she finally woke up it is almost 5 am. its her breakfast time lol
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Quoting 1948. bigwes6844:
yeah if it fires up the morning bloggers are gonna go nuts!

I cant wait to see that hahaha
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Huh. The sattilite page just screwed itself up.

Now its showing nothing there and is stuck without the most recent imagery. Any of the loops drop back to 1 hour old imagery instead of the new shots.



Bizzare. Well lets see what it looks like after this issue is fixed.
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Quoting 1945. DataNerd:



Not quite dead.


Looks like it probably discarded its old LLC and formed this thing.

Its certainly trying to come back despite the odds.
yeah if it fires up the morning bloggers are gonna go nuts!
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Chantal is trying to make a comeback with new bursts of convection near the center:

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Welcome back Chantal!
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Not quite dead.


Looks like it probably discarded its old LLC and formed this thing.

Its certainly trying to come back despite the odds.
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Dang. Some very cold cloud tops with this burst:

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Link



I would like to say this is over and shut the book on it. But the latest burst of thunderstorms is spreading rapidly and growing in intensity. It would appear the forward speed of chantal or whatever is left of it has dropped by anywhere from 10 to 15 mph over the last hour or so and may still be falling.

Hard to tell what is left if anything.


I don't think its going to matter. The center or whatever that is will be over mountainous land soon and increased shear.

This should be a shut case. Lets find out.
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new track
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Quoting 1934. DataNerd:


going to do a tremendous amount of damage wherever it ends up.
its got 5 mph to go till super typhoon
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Really
5:00 AM AST Wed Jul 10
Location: 16.5°N 69.5°W
Moving: WNW at 29 mph
Min pressure: 1011 mb
Max sustained: 45 mph
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G'mornin' -
I go to bed last night with "a burst of convection firing near the center" then wake up to...a blob? Where's Grothar when you need him?
Member Since: October 18, 2005 Posts: 4 Comments: 3052
BULLETIN
TROPICAL STORM CHANTAL ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013
500 AM AST WED JUL 10 2013

...CHANTAL WEAKENING...
...MAY BE DEGENERATING INTO A TROPICAL WAVE...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...16.5N 69.5W
ABOUT 260 MI...420 KM WSW OF SAN JUAN PUERTO RICO
ABOUT 140 MI...225 KM S OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 29 MPH...46 KM/H
MINIMUM CENTRAL PRESSURE...1011 MB...29.85 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE TROPICAL STORM WARNING FOR PUERTO RICO...AND THE TROPICAL STORM
WATCH FOR THE U.S. VIRGIN ISLANDS...VIEQUES...AND CULEBRA ARE
DISCONTINUED.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* ENTIRE COAST OF THE DOMINICAN REPUBLIC
* ENTIRE COAST OF HAITI
* TURKS AND CAICOS
* SOUTHEASTERN BAHAMAS

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* CENTRAL BAHAMAS

INTERESTS IN EASTERN CUBA AND THE NORTHWESTERN BAHAMAS SHOULD
MONITOR THE PROGRESS OF CHANTAL.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.
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TROPICAL STORM CHANTAL DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013
500 AM AST WED JUL 10 2013

OBSERVATIONS FROM A HURRICANE HUNTER MISSION AND NOAA DATA BUOY
42059 INDICATE THAT CHANTAL MAY NO LONGER HAVE A CLOSED
CIRCULATION. THE SATELLITE PRESENTATION OF THE SYSTEM HAS ALSO
DETERIORATED MARKEDLY THIS MORNING...AND IS BARELY CLASSIFIABLE BY
THE DVORAK TECHNIQUE. FLIGHT-LEVEL AND SFMR SURFACE WINDS DO NOT
SUPPORT AN INTENSITY OF MORE THAN 40 KT...AND THE CURRENT WIND
SPEED IS SET AT THAT VALUE. EVEN IF CHANTAL DOES NOT CEASE ITS
EXISTENCE AS A TROPICAL CYCLONE...DYNAMICAL GUIDANCE SHOWS STRONG
WESTERLY SHEAR OVER THE SYSTEM FOR THE NEXT COUPLE OF DAYS. THE
SHEAR...ALONG WITH LAND INTERACTION...SHOULD CAUSE FURTHER
WEAKENING. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE
STATISTICAL-DYNAMICAL LGEM GUIDANCE AND THE INTENSITY MODEL
CONSENSUS.

ALTHOUGH THE CENTER IS DIFFICULT TO TRACK...THE BEST ESTIMATE IS
THAT CHANTAL MOVED VERY RAPIDLY WESTWARD...NEAR 28 KT...OVER THE
PAST SEVERAL HOURS. A MORE CONSERVATIVE...LONGER-TERM...ESTIMATE
OF INITIAL MOTION IS 285/25. A WELL-DEFINED MID-LEVEL RIDGE TO THE
NORTH OF THE STORM HAS BEEN STEERING IT QUICKLY WESTWARD TO
WEST-NORTHWESTWARD. A WEAKNESS IN THE RIDGE IN THE VICINITY OF THE
EASTERN GULF OF MEXICO AND THE FLORIDA PENINSULA SHOULD RESULT IN
CHANTAL...OR ITS REMNANT...TURNING TOWARD THE NORTHWEST AND NORTH
OVER THE NEXT FEW DAYS. SINCE THE INITIAL POSITION HAS BEEN
SHIFTED SUBSTANTIALLY WESTWARD IN COMPARISON TO THE PREVIOUS
ADVISORY... THIS NECESSITATES A LARGE WESTWARD SHIFT TO THE NHC
FORECAST TRACK. NONETHELESS...THE NEW OFFICIAL FORECAST IS STILL
ON THE EASTERN SIDE OF THE TRACK MODEL GUIDANCE SUITE.

SINCE THE CYCLONE MAY BE OPENING UP INTO A WAVE...ADVISORIES MAY BE
DISCONTINUED LATER TODAY.

FORECAST POSITIONS AND MAX WINDS

INIT 10/0900Z 16.5N 69.5W 40 KT 45 MPH
12H 10/1800Z 17.8N 72.3W 35 KT 40 MPH
24H 11/0600Z 19.5N 75.7W 30 KT 35 MPH
36H 11/1800Z 21.5N 78.5W 30 KT 35 MPH...INLAND
48H 12/0600Z 23.8N 79.5W 30 KT 35 MPH
72H 13/0600Z 27.5N 80.0W 30 KT 35 MPH
96H 14/0600Z 31.0N 81.0W 35 KT 40 MPH
120H 15/0600Z 32.5N 82.0W 25 KT 30 MPH...INLAND

$$
FORECASTER PASCH/BLAKE
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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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