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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Chantal looks ragged right now due to 15 to 20knts of NWLY wind shear.
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Using two different handles are we?

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Quoting 812. Chicklit:

You keep doing your thing Cowboy.
We enjoy reading your prognostications.
There's nothing wrong with 'the ole fashion way'



Thank you, Chick! :) I know you believe in a WV loop too! Seen you post 'em several times.
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San Juan
NEXRAD Radar

Velocity Azimuth Display Wind Profile ° Elevation
Range 124 NMI

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Quoting 763. indianrivguy:


my girlfriends phone just did the noise when Sammy krinkles her nose.. its her text alert...



My ring tone and text alert were the horn at 44 seconds into this vid. After three days my friends said they would have me drawn and quartered if I didn't change it.
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Quoting 818. JRRP:

Further west and slightly south
Member Since: September 2, 2011 Posts: 0 Comments: 1148
Taz, mods would do their job much better if you minuses or report their posts instead of engaging with them. Mods told me that it's the fastest way they're gone. It's how they do their job.
Member Since: August 1, 2011 Posts: 28 Comments: 8027
Quoting 820. will40:


i only see him when someone quotes him




i wounder why they have not fixes the : Quote too where you have some one on Ignore you cant seem them when they get Quoteed
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San Juan
NEXRAD Radar

Base Reflectivity 0.50° Elevation
Range 248 NMI

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looks to me based on the 8pm coordinates that the nhc crossed the supposed center and found only east winds

guess the center is further south then
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Lets get back on track and focus on the storm,thanks.
Member Since: July 2, 2013 Posts: 0 Comments: 1521
i see a yellow dot

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Quoting 819. Chicklit:

I don't see it anymore



lol good girl
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At 23:57:30Z (last observation), the observation was 233 miles (375 km) to the SSE (163°) from San Juan, Puerto Rico (USA).


Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 10th day of the month at 00:04Z
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: 08

23:57:30Z 15.183N 65.050W 843.0 mb
(~ 24.89 inHg) 1,604 meters
(~ 5,262 feet) 1014.8 mb
(~ 29.97 inHg) - From 111° at 27 knots
(From the ESE at ~ 31.0 mph) 16.0°C
(~ 60.8°F) 15.8°C
(~ 60.4°F) 33 knots
(~ 37.9 mph) 40 knots
(~ 46.0 mph) 2 mm/hr
(~ 0.08 in/hr) 32.7 knots (~ 37.6 mph)
121.2%
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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Quoting 813. will40:
if you guys would stop feeding it it will go away


Clearly, you've never met a "good" troll, have you?
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Quoting 817. Tazmanian:



or if the mods do there job and get the ban hammer out this troll would be gone


i only see him when someone quotes him
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Quoting 813. will40:
if you guys would stop feeding it it will go away

I don't see it anymore
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818. JRRP
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Quoting 813. will40:
if you guys would stop feeding it it will go away



or if the mods do there job and get the ban hammer out this troll would be gone
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Still looks like crap :(



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Quoting 811. Tazmanian:



yep hes nothing but a anyouing troll


I reported him
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never seen the term "hot tower" misused as much I have on here the last two days
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if you guys would stop feeding it it will go away
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Quoting 792. moonlightcowboy:
Don't get me wrong, please. Now these models have gone and gotten dawg-gone smart, they have. Last couple of years I've been fairly impressed. And, I've been taken aback at how sharp, accurate some of the newer and younger bloggers that have come along are - quite impressive, and I look forward to their posts, and mostly why I've just mostly lurked the past couple years. They've had it all covered pretty good. :)

This season's atmospheric setup with ENSO and the potential position and strength of the B/A High has had me tuned in particularly. I'm not liking what I see in as far as the potential seriousness of this season.

And, with Chantal, I've just read the charts, mostly use a sfc map and a water vapor loop, and relate what I think is happening. Not scientific at all, just old-school observations and thoughts. I'm prolly wrong about Chantal, but we'll see. Nonetheless, even weak and possibly dissipating, she'll still bring some hurt to some folks in her path.

You keep doing your thing Cowboy.
We enjoy reading your prognostications.
There's nothing wrong with 'the ole fashion way'
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Quoting 808. WDEmobmet:


You no i have never put anyone on iggy but gessss i am right there with you taz. Getting old very old



yep hes nothing but a anyouing troll
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Quoting 788. Slamguitar:
So I'm in the kitchen making cookies, and when I cook I like to watch or listen to something, I decide to flip it to TWC and see Cantore giving the tropical update. WOW, he's not good at this at all, you can tell he never does anything with tropical weather except stand in it.


He is the meathead at the weather channel, not that that is bad thing but it is funny to see him in a suit.
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Recon heading near 15N 64W
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Quoting 800. Tazmanian:




ok poof you go


You no i have never put anyone on iggy but gessss i am right there with you taz. Getting old very old
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Quoting 791. Camille33:
Hot towers are exploding right now they signify extreme ascending motion in the inner core and the formation of an eye wall.



there is no eyewall fourming we may not even have a name storm but the HH is out there now so will see
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Quoting 794. jeffreeysweetypie:
ok this sums it up ..... anyone from maine to california needs to watch chantal... that is about accurate as it gets from hour to hour.... gotta love the models and forcasters a true science


Troll....Bye Bye
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Quoting 786. Chicklit:

wow, this is surprising:
MAXIMUM SUSTAINED WINDS ARE NEAR 65 MPH...100 KM/H...WITH HIGHER GUSTS. THESE WINDS ARE CONFINED TO A SMALL AREA TO THE EAST THE CENTER. CHANTAL IS FORECAST TO BE NEAR HURRICANE STRENGTH BEFORE REACHING HISPANIOLA.



Agree , well let's see what ahead towards us PR
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Quoting 759. SLU:
The last few visible frames did show a closed circulation. I expect that the RECON will still find westerlies. Quite remarkable. This really is a storm unlike what we've grown accustomed to in the past.



Right... And when it gets in a more condussive environment, look out. This one may not be the big one, in fact all signs are it will not be, but it will most likely trend further West due to its current weak state. It will not get proofed by high mountains. And it will moisten the environment ahead of the next couple of systems. Get ready GOM... If not this one the next few will be threatening the Gulf.
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Quoting 789. FOREX:


this track is bogus now.


bogus or not it is the NHC track
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Quoting 782. FutureWx6221:
I cannot for the life of me understand how Chantal could have such poor convective structure, and yet contain such a well formed surface circulation accompanied by moderate winds extending outwards a good distance (post 672, yes, I'm aware everyone thinks those are unreliable, but trust me, even if it is partially wrong, the previous HH mission certainly provided evidence of the circulation).

If anyone can explain this phenomenon, it would be greatly appreciated. TIA

-FW6



Well the circulation isn't "well formed" plain and simple
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Quoting 794. jeffreeysweetypie:
ok this sums it up ..... anyone from maine to california needs to watch chantal... that is about accurate as it gets from hour to hour.... gotta love the models and forcasters a true science




ok poof you go
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Quoting 759. SLU:
The last few visible frames did show a closed circulation. I expect that the RECON will still find westerlies. Quite remarkable. This really is a storm unlike what we've grown accustomed to in the past.

the fact that its moving so fast (26 mph) makes the north side winds really only 34mph . I think thats why we are so amazed at the wind speed.
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At 23:47:30Z (last observation), the observation was 221 miles (356 km) to the SSE (155°) from San Juan, Puerto Rico (USA)

Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 9th day of the month at 23:47Z
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: 07

23:47:30Z 15.517N 64.633W 842.9 mb
(~ 24.89 inHg) 1,603 meters
(~ 5,259 feet) 1014.2 mb
(~ 29.95 inHg) - From 150° at 39 knots
(From the SSE at ~ 44.8 mph) 16.4°C
(~ 61.5°F) 12.4°C
(~ 54.3°F) 40 knots
(~ 46.0 mph) 32 knots
(~ 36.8 mph) 0 mm/hr
(~ 0 in/hr) 31.2 knots (~ 35.9 mph)
80.0%
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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Quoting 787. jeffreeysweetypie:
wheres that big left turn right into central east coast florida they were showing the past 4 days? what happened to that track?


track changes with each new set of model runs that come out
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8pm
15.4n 64.9w
65mph
wnw 26mph
1006mb

That would be 0.2n vs 1.2w ratio in the past 3 hours. So yes, the observation that it appeared to be taking a westerly motion are verified by NHC.
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Quoting 777. Tazmanian:




LOL



recon will tell you if its a open wave not by looking at the IR


Understand that Taz come one... doenst hurt to be optimistic
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Don't get me wrong, please. Now these models have gone and gotten dawg-gone smart, they have. Last couple of years I've been fairly impressed. And, I've been taken aback at how sharp, accurate some of the newer and younger bloggers that have come along are - quite impressive, and I look forward to their posts, and mostly why I've just mostly lurked the past couple years. They've had it all covered pretty good. :)

This season's atmospheric setup with ENSO and the potential position and strength of the B/A High has had me tuned in particularly. I'm not liking what I see in as far as the potential seriousness of this season.

And, with Chantal, I've just read the charts, mostly use a sfc map and a water vapor loop, and relate what I think is happening. Not scientific at all, just old-school observations and thoughts. I'm prolly wrong about Chantal, but we'll see. Nonetheless, even weak and possibly dissipating, she'll still bring some hurt to some folks in her path.
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Hot towers are exploding right now they signify extreme ascending motion in the inner core and the formation of an eye wall.
Member Since: July 2, 2013 Posts: 0 Comments: 1521
Quoting 776. indianrivguy:


Deepthroat again?


Ummmmmmm??>???? o wait nevermind :P
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789. FOREX
Quoting 780. Walshy:


this track is bogus now.
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So I'm in the kitchen making cookies, and when I cook I like to watch or listen to something, I decide to flip it to TWC and see Cantore giving the tropical update. WOW, he's not good at this at all, you can tell he never does anything with tropical weather except stand in it.
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Quoting 770. BaltimoreBrian:
Chantal's 8 p.m. advisory by the NHC is out.

wow, this is surprising:
MAXIMUM SUSTAINED WINDS ARE NEAR 65 MPH...100 KM/H...WITH HIGHER GUSTS. THESE WINDS ARE CONFINED TO A SMALL AREA TO THE EAST THE CENTER. CHANTAL IS FORECAST TO BE NEAR HURRICANE STRENGTH BEFORE REACHING HISPANIOLA.

Member Since: Posts: Comments:

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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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