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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2586. will40
track shifted east
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Quoting 2563. dfwstormwatch:
Time:14:35:00ZCoordinates:16.1667N 71.8667WAcft. Static Air Press:927.6 mb (~ 27.39 inHg)Acft. Geopotential Hgt:774 meters (~ 2,539 feet)Extrap. Sfc. Press:1013.6 mb (~ 29.93 inHg)D-value:-Flt. Lvl. Wind (30s):From 173° at 11 knots (From the S at ~ 12.6 mph)Air Temp:19.1°C (~ 66.4°F)Dew Pt:17.1°C (~ 62.8°F)Peak (10s) Flt. Lvl. Wind:14 knots (~ 16.1 mph)SFMR Peak (10s) Sfc. Wind:69 knots* (~ 79.3 mph*)SFMR Rain Rate:46 mm/hr* (~ 1.81 in/hr*)(*) Denotes suspect data


Wow yeah.

surface wind being higher than flight does happen from time to time, but if that were legit it would be the biggest I've ever seen. Waterspout is most plausible explanation IMO.
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She never shocks me anymore. She has a mind of her own
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2583. IKE

Quoting hurricanes2018:
its a tropical wave CHANTAL now!!
No.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting 2565. SFLWeatherman:
11:01 is late not 10:58


HE posted that message at 10:55 EDT.
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BULLETIN
TROPICAL STORM CHANTAL ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013
1000 AM EST WED JUL 10 2013

...AIR FORCE RECONNAISSANCE PLANE FINDS THAT CHANTAL IS STILL A
TROPICAL STORM...
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Quoting 2423. moonlightcowboy:
Good morning, weathergeeks! :)

Chantal must have had a rough time last night, nearly looks to be an open wave, but there is still cyclonic turning and decent symmetrical inflows. I suspect it's trying to get its act back together. We know there had to be a vigorous low-level spin to survive all the dry air it has passed through already, so I'm doubting that it's willing to give up its ghost yet.

It does appear, at least to me, that it will continue to follow the more westerly track around the periphery of the 1016mb isobar high pressure that I've been mentioning for several days now, barely grazing Hispaniola if interacting with it at all. Mid-level shear is conducive and upper-level shear is forecast to relax in its path ahead.



Now, does it cross over the tip of eastern Cuba directly towards the ULL? Maybe, but present disorganization will only deteriorate more if it does. Idiom still is that weaker is west, still embedded within the still fairly strong, low/mid level easterly flow which means more towards Jamaica, either just south of the island or possibly in between it and the central part of Cuba. It should have time to reorganize by that point as well, especially as it comes into warmer, deeper TCHP waters there.



If it remains weak it'll track even further west where both TCHP values and upper level shear will be stronger. If it gains some strength it'll feel the tug of the retrograding ULL and eventually make the crossing over Cuba and into the GoM and the Gulf Stream. From there, my guess again, would be for it to head towards Apalacicola to Fort Meyers still.

Good analysis... hope u posted this whole thing in your own blog...
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2579. 62901IL
Member Since: June 14, 2013 Posts: 2 Comments: 2004
TROPICAL STORM CENTER LOCATED NEAR 16.5N 72.0W AT 10/1500Z
POSITION ACCURATE WITHIN 70 NM

Horseshoes and handgrandes LOL
Member Since: September 23, 2005 Posts: 15 Comments: 11346
2577. IKE
FORECAST VALID 13/1200Z 30.0N 80.0W...POST-TROP/REMNT LOW
MAX WIND 25 KT...GUSTS 35 KT.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Looks like she is trying to wrap up.

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2575. Dakster
It's out --- Happy now? Still a storm too.
Member Since: March 10, 2006 Posts: 0 Comments: 10815
2574. will40
its out now and im am shocked lol
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Quoting 2554. hurricanes2018:
its a tropical wave CHANTAL now!!

Do you think it will reform again?
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...AIR FORCE RECONNAISSANCE PLANE FINDS THAT CHANTAL IS STILL A TROPICAL STORM...

10:00 AM EST Wed Jul 10
Location: 16.5N 72.0W
Moving: W at 29 mph
Min pressure: 1011 mb
Max sustained: 45 mph
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2571. 62901IL
BULLETIN
TROPICAL STORM CHANTAL ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013
1000 AM EST WED JUL 10 2013

...AIR FORCE RECONNAISSANCE PLANE FINDS THAT CHANTAL IS STILL A
TROPICAL STORM...


SUMMARY OF 1000 AM EST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.5N 72.0W
ABOUT 335 MI...535 KM ESE OF KINGSTON JAMAICA
ABOUT 145 MI...235 KM S OF PORT AU PRINCE HAITI
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 29 MPH...46 KM/H
MINIMUM CENTRAL PRESSURE...1011 MB...29.85 INCHES
Member Since: June 14, 2013 Posts: 2 Comments: 2004
2570. IKE
WTNT23 KNHC 101457
TCMAT3

TROPICAL STORM CHANTAL FORECAST/ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013
1500 UTC WED JUL 10 2013

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

THE GOVERNMENT OF JAMAICA HAS ISSUED A TROPICAL STORM WATCH FOR
JAMAICA

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
* JAMAICA

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

TROPICAL STORM CENTER LOCATED NEAR 16.5N 72.0W AT 10/1500Z
POSITION ACCURATE WITHIN 70 NM

PRESENT MOVEMENT TOWARD THE WEST OR 280 DEGREES AT 25 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1011 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 90NE 0SE 0SW 0NW.
12 FT SEAS.. 60NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 16.5N 72.0W AT 10/1500Z
AT 10/1200Z CENTER WAS LOCATED NEAR 16.5N 71.3W

FORECAST VALID 11/0000Z 18.1N 75.5W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 90NE 0SE 0SW 0NW.

FORECAST VALID 11/1200Z 20.0N 78.2W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 12/0000Z 22.5N 80.0W
MAX WIND 25 KT...GUSTS 35 KT.

FORECAST VALID 12/1200Z 25.0N 80.5W
MAX WIND 25 KT...GUSTS 35 KT.

FORECAST VALID 13/1200Z 30.0N 80.0W...POST-TROP/REMNT LOW
MAX WIND 25 KT...GUSTS 35 KT.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 14/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 16.5N 72.0W

NEXT ADVISORY AT 10/2100Z

$$
FORECASTER AVILA
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting 2559. StormTrackerScott:
Worst case track IMO now that she is missing Haiti to the south. FL better be on gaurd!!


I am sorry but actually that's the best thing that could've happened. I'd rather see a minimal Hurricane hit Florida than a tropical storm hit Haiti. This could've caused well over 100 deaths in Haiti, while in Florida we will probably just see some minor damage.
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She is not dead yet.
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2567. Dakster
Quoting 2560. boltdwright:


It is not even 11am yet...


We get spoiled because the NHC typically releases the advisories early. I bet they are waiting for some recon to come back before releasing it on time.
Member Since: March 10, 2006 Posts: 0 Comments: 10815
2566. jeebsa
Very interesting for sure
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11:01 is late not 10:58
Quoting 2555. FIUStormChaser:
11am is late....
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Quoting 2560. boltdwright:


It is not even 11am yet...


No, but they are usually 20 minutes ahead of time so news media has time to prep for the advisory at the top of the hour.
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Time:14:35:00ZCoordinates:16.1667N 71.8667WAcft. Static Air Press:927.6 mb (~ 27.39 inHg)Acft. Geopotential Hgt:774 meters (~ 2,539 feet)Extrap. Sfc. Press:1013.6 mb (~ 29.93 inHg)D-value:-Flt. Lvl. Wind (30s):From 173° at 11 knots (From the S at ~ 12.6 mph)Air Temp:19.1°C (~ 66.4°F)Dew Pt:17.1°C (~ 62.8°F)Peak (10s) Flt. Lvl. Wind:14 knots (~ 16.1 mph)SFMR Peak (10s) Sfc. Wind:69 knots* (~ 79.3 mph*)SFMR Rain Rate:46 mm/hr* (~ 1.81 in/hr*)(*) Denotes suspect data
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2562. LargoFl
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Quoting 2555. FIUStormChaser:
11am is late....


I think NHC is baffled about what they need to post for the advisory. They can't over play it, but if they downplay the intensity everyone will throw a fit again. It's understandable, because nothing makes sense about this storm anyway.
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Quoting 2555. FIUStormChaser:
11am is late....


It is not even 11am yet...
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Worst case track IMO now that she is missing Haiti to the south. FL better be on gaurd!!
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Quoting 2510. fabian171017:
I expect Chantal to move into the Gulf strenghtening into an upper end Cat. 2 Hurricane. Then it should move over Florida and up the East Coast steadily strenghtening into Cat. 4 Hurricane striking NYC with 150 mph.

This is sarcasm I am pretty sure
only one Cat 4 has made it to North Carolina one in NYC would be near impossible to pull of especially in July
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Flight level
From 147° at 17 knots
(From the SSE at ~ 19.5 mph)

SFMR
66 knots
(~ 75.9 mph)

Rain
61 mm/hr
(~ 2.40 in/hr)

Totally bogus SFMR
Member Since: September 23, 2005 Posts: 15 Comments: 11346
Quoting 2545. will40:


did flight level verify that it wasnt suspect?


Light winds at flight level. There was a steady lead up to and then down from the 70mph reading. Was not denoted as suspect, could be however.
Member Since: August 19, 2005 Posts: 5 Comments: 5458
11am is late....
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its a tropical wave CHANTAL now!!
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The little train that could? Looks like she's got that never-say-die attitude.

Member Since: October 18, 2005 Posts: 4 Comments: 3052
Chantal appears to be heading WNW.
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Quoting 2541. ProgressivePulse:
Those 70+MPH readings were in the NE quad just east of the supposed center.


Some of those winds are being verified at the coast now.
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Quoting 2541. ProgressivePulse:
Those 70+MPH readings were in the NE quad just east of the supposed center.


Yeah but was it in the right direction? Was it a waterspout, or was it TS cyclonic winds?
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Winds gusting 50 to 60 mph across the Southern Dominican Coast. Chantal is damm near putting up a fight this morning. Geesh!
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Quoting 2510. fabian171017:
I expect Chantal to move into the Gulf strenghtening into an upper end Cat. 2 Hurricane. Then it should move over Florida and up the East Coast steadily strenghtening into Cat. 4 Hurricane striking NYC with 150 mph.


LOL...ok, just bite your tongue. I'm not doing that again. (from south shore of Long Island)!!!
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2547. LargoFl
Looks OK on the Sat pic..................
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Chantal is phenominal. And yet the season has hardly started. What will happen when the trade winds wind down and the SST gets toasty?

Yikes! for sure.
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2545. will40
Quoting 2541. ProgressivePulse:
Those 70+MPH readings were in the NE quad just east of the supposed center.


did flight level verify that it wasnt suspect?
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Quoting 2537. stormpetrol:
Time: 14:21:00Z
Coordinates: 16.6333N 71.7167W
Acft. Static Air Press: 924.8 mb (~ 27.31 inHg)
Acft. Geopotential Hgt: 802 meters (~ 2,631 feet)
Extrap. Sfc. Press: 1013.3 mb (~ 29.92 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 300° at 6 knots (From the WNW at ~ 6.9 mph)
Air Temp: 21.1°C (~ 70.0°F)
Dew Pt: 19.5°C (~ 67.1°F)
Peak (10s) Flt. Lvl. Wind: 8 knots (~ 9.2 mph)
SFMR Peak (10s) Sfc. Wind: 15 knots (~ 17.2 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)
(*) Denotes suspect data


That helps. I'll call it 16.7n and 72w, w/ 45mph winds.
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I am thinking that if Chantal weakens a little bit, it could become a concern to western portions of the Gulf. If chantal stays weak, it won't feel this trough as much and will move south of forecast track. Shear also drops off slightly to the west of the storm and possible re-intensification could occur. It is an interesting scenario but it is only one of many.
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Those 70+MPH readings were in the NE quad just east of the supposed center.
Member Since: August 19, 2005 Posts: 5 Comments: 5458
2540. Dakster
Quoting 2527. TylerStanfield:
Recon found a closed Circulation. Very, very ill defined. But it's still there, amazingly.


Chantal never ceases to amaze.
Member Since: March 10, 2006 Posts: 0 Comments: 10815
Well, they have at least 42.6mph wind just to the NE of the intuitive center fix, so that would still justify the warning level of TS "near 45mph".
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Quoting 2489. LargoFl:
remember folks this system may look bad right now, but wait till it hits the gulf stream whose waters are very warm its not over til she sings huh


The water it is moving over now is every bit as warm



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Time: 14:21:00Z
Coordinates: 16.6333N 71.7167W
Acft. Static Air Press: 924.8 mb (~ 27.31 inHg)
Acft. Geopotential Hgt: 802 meters (~ 2,631 feet)
Extrap. Sfc. Press: 1013.3 mb (~ 29.92 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 300° at 6 knots (From the WNW at ~ 6.9 mph)
Air Temp: 21.1°C (~ 70.0°F)
Dew Pt: 19.5°C (~ 67.1°F)
Peak (10s) Flt. Lvl. Wind: 8 knots (~ 9.2 mph)
SFMR Peak (10s) Sfc. Wind: 15 knots (~ 17.2 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)
(*) Denotes suspect data
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Quoting 2530. RTSplayer:


Is that surface? Or flight?

If that's surface that would be incredible given the poor presentation.


Estimated Surface Wind (30 sec. Avg.)
Using Estimated Reduction Factor

SFMR
Peak (10s Avg.) Sfc. Wind
64 knots
(~ 73.6 mph)
Member Since: August 19, 2005 Posts: 5 Comments: 5458

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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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