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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At 22:57:30Z (last observation), the observation was 147 miles (236 km) to the ESE (120°) from San Juan, Puerto Rico (USA).


Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 9th day of the month at 22:56Z
Date: July 9, 2013
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number: 03
Storm Name: Chantal (flight in the North Atlantic basin)
Mission Number: 3
Observation Number: 02

22:57:30Z 17.350N 64.133W 845.6 mb
(~ 24.97 inHg) 1,603 meters
(~ 5,259 feet) 1017.4 mb
(~ 30.04 inHg) - From 125° at 45 knots
(From the SE at ~ 51.7 mph) 16.2°C
(~ 61.2°F) 12.2°C
(~ 54.0°F) 46 knots
(~ 52.9 mph) - - - -
Time Coordinates Aircraft
Static Air Pressure Aircraft
Geopotential Height Extrapolated
Surface Pressure D-value Flight Level Wind (30 sec. Avg.) Air Temp. Dew Point Peak (10 sec. Avg.)
Flight Level Wind SFMR
Peak (10s Avg.) Sfc. Wind SFMR
Rain Rate Estimated Surface Wind (30 sec. Avg.)
Using Estimated Reduction Factor Peak Wind at Flight Level to
Est. Surface Reduction Factor
HDOB Observations
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I think the "tilt" or misalignment of COC has finally taken its toll ....let's see what the recon data says...
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When will we see our first photogenic storm?
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Probably will amaze or shock some what the HHs will find on this mission, just sayin....
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Quoting 573. weatherlover94:
there is no way Chantal is a 65 mph open wave
I have a hard time believing she is even a tropical storm right now, just my opinion tho of course
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Hello everyone from Louisiana!!! Watching Chantal...I have a question...how can you keep this blog from automatically refreshing on ya?!?! It is hard to read anything when your page keeps refreshing.....UGH....


TIA!

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Quoting 573. weatherlover94:
there is no way Chantal is a 65 mph open wave


Irene was a 60 mph open wave prior to naming
Member Since: June 17, 2011 Posts: 11 Comments: 6493
Quoting 573. weatherlover94:
there is no way Chantal is a 65 mph open wave




yes it can i think we say some in like this with dolly i think dolly was a open wave and had 50mph winds if i recall and i think dr m all so called that storm a joker
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Also... GFS please stop with the ghost storms.. Thanks.
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Time: 22:53:00Z
Coordinates: 17.45N 64.3W
Acft. Static Air Press: 845.6 mb (~ 24.97 inHg)
Acft. Geopotential Hgt: 1,602 meters (~ 5,256 feet)
Extrap. Sfc. Press: 1017.6 mb (~ 30.05 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 116° at 47 knots (From the ESE at ~ 54.0 mph)
Air Temp: 15.5°C (~ 59.9°F)
Dew Pt: 13.6°C (~ 56.5°F)
Peak (10s) Flt. Lvl. Wind: 47 knots (~ 54.0 mph)
SFMR Peak (10s) Sfc. Wind: -
SFMR Rain Rate: -
(*) Denotes suspect data

yep recon will be there in 45 min to 1 hour.
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I am changing my track,track will be out shortly.
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Quoting 570. wunderkidcayman:

hmm not too shabby


yes it was a typo error by Hunter crew



no they moved tomorrows task to today and are going to write up tomorrows task

if you check the nhc page, they are both the same
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there is no way Chantal is a 65 mph open wave
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Lol how can I describe the "Chantal event" over me : another huge bust! We were supposed to get rain from it... and of course haven't got a drop today....

Whuut... :)
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Sure don't need any more rain here in coastal SC....
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Quoting 559. stormpetrol:

hmm not too shabby

Quoting 561. TropicalAnalystwx13:

That says 11/0000z, which is this time tomorrow night, but not now.

But apparently the plane is enroute.

So confused lol.

yes it was a typo error by Hunter crew

Member Since: June 13, 2009 Posts: 2 Comments: 12019
Quoting 561. TropicalAnalystwx13:

That says 11/0000z, which is this time tomorrow night, but not now.

But apparently the plane is enroute.

So confused lol.
Oops my bad.
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Quoting 548. TropicalAnalystwx13:
Why is everybody saying recon is going into the storm?

I don't see a mission scheduled.

they say seeing is believing
Member Since: June 17, 2011 Posts: 11 Comments: 6493
567. FOREX
Quoting 562. stormwatcherCI:
Link

On the way.

yellow crayon coming.
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Yee-haw, there goes recon! Goin out to investigate our thingy-mc-blob, Chantal


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i think they find a open wave
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Quoting 548. TropicalAnalystwx13:
Why is everybody saying recon is going into the storm?

I don't see a mission scheduled.
Link

On the way.
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Quoting 554. GTstormChaserCaleb:
Should be in an hour, TA 8 PM EDT.

I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM CHANTAL
FLIGHT ONE -- TEAL 71 FLIGHT TWO -- TEAL 72
A. 11/0000Z,0600Z A. 11/1200Z,1800Z
B. AFXXX 0503A CHANTAL B. AFXXX 0603A CHANTAL
C. 10/2215Z C. 11/0945Z
D. 20.0N 71.4W D. 21.3N 73.6W
E. 10/2330Z TO 11/0600Z E. 11/1130Z TO 11/1800Z
F. SFC TO 10,00 FT F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES WHILE
CHANTAL REMAINS A THREAT.

That says 11/0000z, which is this time tomorrow night, but not now.

But apparently the plane is enroute.

So confused lol.
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Quoting 545. will40:


yes and when Raleigh has to release their Dam it makes things worse downstream in the Neuse River


Totally agree, the flood control lakes. Falls-Neuse River and Jordan-Cape Fear are 6ft over as of this weekend. Flooding is sporadic all down these systems to the coast, not to mention the damage from the stagnate waters in the swamps would have on Marine life due to the lack of oxygen.
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Quoting 551. weatherlover94:
Is it just me or is Chantal moving due west again ?

Look that way

Quoting 552. Tazmanian:



recon up


Link

Wow what really already hmm
Member Since: June 13, 2009 Posts: 2 Comments: 12019
Quoting 548. TropicalAnalystwx13:
Why is everybody saying recon is going into the storm?

I don't see a mission scheduled.


earlier i saw 8:00 PM tonight bur havnt looked at POTD
lately
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Quoting 534. Gearsts:
System is looking worst in every new loop, Levi nailed this system very well.



Circulation is outside the range of the radar, so I'm not sure what your point would be.
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555. FOREX
Quoting 551. weatherlover94:
Is it just me or is Chantal moving due west again ?


yes it is.
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Quoting 548. TropicalAnalystwx13:
Why is everybody saying recon is going into the storm?

I don't see a mission scheduled.
Should be in an hour, TA 8 PM EDT.

I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM CHANTAL
FLIGHT ONE -- TEAL 71 FLIGHT TWO -- TEAL 72
A. 11/0000Z,0600Z A. 11/1200Z,1800Z
B. AFXXX 0503A CHANTAL B. AFXXX 0603A CHANTAL
C. 10/2215Z C. 11/0945Z
D. 20.0N 71.4W D. 21.3N 73.6W
E. 10/2330Z TO 11/0600Z E. 11/1130Z TO 11/1800Z
F. SFC TO 10,00 FT F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES WHILE
CHANTAL REMAINS A THREAT.
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Quoting 525. weatherlover94:


What would it take for a charley track and would conditions be more or less favorable if it where to pull a charley track ?

Hmm I'm thinking maybe weakening of the ULL building of Bermuda high as well building of NE GOM high this however is highly dependant on what chantal does it's pressure it's organisation it's location it's
I'd say the conditions could be better IMO


Quoting 533. Stormchaser121:
Are the models getting confused?? Whats going on?

Nope their not they are just shift off westward
Member Since: June 13, 2009 Posts: 2 Comments: 12019
Quoting 548. TropicalAnalystwx13:
Why is everybody saying recon is going into the storm?

I don't see a mission scheduled.



recon up


Link
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Is it just me or is Chantal moving due west again ?
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She's dead, Jim.
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i believe it was the 18z GFS brought her ashore on Fla Ga border
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Why is everybody saying recon is going into the storm?

I don't see a mission scheduled.
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Quoting 544. weatherlover94:



It may not even pass over the most highest mountain region of Hispaniola. Does anybody think if all models drop it that the NHC will drop it to a 3 day cone and call for dissipation there after ?


Off of one model run? That would be foolish. It would need several runs showing consensus. Quite honestly, waiting until Chantal pops off the mountains is the best course of action.
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Quoting 542. ncstorm:


I have said from day one that the GFS and the other models have been inconsistent with Chantal..the CMC constantly has been showing a storm affecting the SE coast..I'm going with the CMC on this one..
It has been the most consistent. I am waiting to see what the GFDL and HWRF show as they have been fairly consistent in showing a strengthening storm in the Bahamas.
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Quoting 541. crzyboutncweather:


No doubt, if for some reason we do get a storm, this year seems to be setting up like 96 when Fran ran up the Cape Fear in that we had a ton of rain prior and the ground was really soft. Trees down and mass damage all the way past Raleigh. Not that anyone in the SE states would fare any better.


yes and when Raleigh has to release their Dam it makes things worse downstream in the Neuse River
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Quoting 542. ncstorm:


I have said from day one that the GFS and the other models have been inconsistent with Chantal..the CMC constantly has been showing a storm affecting the SE coast..I'm going with the CMC on this one..



It may not even pass over the most highest mountain region of Hispaniola. Does anybody think if all models drop it that the NHC will drop it to a 3 day cone and call for dissipation there after ?
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Models are tightly clustered in agreement out 24-30 hrs, then they diverge as they should..with uncertainly still downstream.

Models are tools, never gospel.

Look for "consensus", as they all have a role in a solution.

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Quoting 535. GTstormChaserCaleb:
Honestly the CMC model is the only model yet to really drop Chantal after its passage over Hispaniola. I guess we will see what tonight brings.


I have said from day one that the GFS and the other models have been inconsistent with Chantal..the CMC constantly has been showing a storm affecting the SE coast..I'm going with the CMC on this one..
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Quoting 517. will40:


I agree some rivers are running over as it is


No doubt, if for some reason we do get a storm, this year seems to be setting up like 96 when Fran ran up the Cape Fear in that we had a ton of rain prior and the ground was really soft. Trees down and mass damage all the way past Raleigh. Not that anyone in the SE states would fare any better.
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the track is about as certain as Debbys was last year
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Quoting 531. MechEngMet:


What happened to 456?


Family obligations, as far as I know.
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537. JRRP
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Quoting 533. Stormchaser121:
Are the models getting confused?? Whats going on?


They haven't known what to do with it since it formed both intensity and track wise
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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.