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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Quoting 1170. stormpetrol:
There is a center it's just not where they expected it to be! Its further south they need to fly around 14.5 N and well west of 65W, they'll find west winds.

hmm could be

Quoting 1173. weatherlover94:
the NHC is going to have to shift everything south and west tonight

yep

Quoting 1181. MechEngMet:


Concur; They are looking too far North.

that make no sense you disagree then you agree

Quoting 1186. Grothar:
Really shifted west.



yep

Quoting 1190. GeoffreyWPB:
A little shift to the east....


nah West

Member Since: June 13, 2009 Posts: 2 Comments: 11215
1235. hydrus
Quoting 1168. Patrap:
Looks like someone dropped an egg.
Soulik is a bona-fide monster.
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1234. Patrap
The Chart


Ahh, ah, ahhhh, ah, ahhhhh....

Member Since: July 3, 2005 Posts: 421 Comments: 127664
Quoting 1206. RTSplayer:


They are in the storm, but for some reason they aren't looking in the right locations to find the center and closed low.

I don't know why they flew the route they did since it wasn't a very good clover shape like normal.


If that is the case they are flying around its environment a little bit to put more data into the model.
Member Since: May 25, 2012 Posts: 0 Comments: 2043


would that be our center showing up on the long range now?
Member Since: September 7, 2005 Posts: 7 Comments: 1494
Quoting 1228. weatherlover94:



Hello and welcome to the blog. It is really to early to tell right now....stick with us for the next few days as we all work together to figure out where it's going and what it might do
good answer.
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Quoting 1216. topgunflightacademy:
Hello All! 1st post for the season and 1st time on wunderground... Been doing some reading on this blog which i find very diverse and very helpful on understanding these tropical systems... Can anyone provide a synopsis on whether south florida may see tropical force winds for the weekend or is to early to tell? We own an aviation business in miami and am contemplating moving our aircraft away from this thing...




To early, but to be honest, unlikely. Any landfall in FL would occur north of WPB. Dont get sucked into the fools posting atm, never the less, stay prepared and stay tuned. Thank You
Member Since: July 21, 2010 Posts: 0 Comments: 1083
Quoting 1219. Astrometeor:


It's still July ya know. Wait till mid-August and if you still have that complaint, then I will agree there's an issue.


I agree, just seemed like it was stacking up, then poof.
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Quoting 1216. topgunflightacademy:
Hello All! 1st post for the season and 1st time on wunderground... Been doing some reading on this blog which i find very diverse and very helpful on understanding these tropical systems... Can anyone provide a synopsis on whether south florida may see tropical force winds for the weekend or is to early to tell? We own an aviation business in miami and am contemplating moving our aircraft away from this thing...



Hello and welcome to the blog. It is really to early to tell right now....stick with us for the next few days as we all work together to figure out where it's going and what it might do
Member Since: September 8, 2010 Posts: 0 Comments: 2141
goodnight everybody ..thank for the information on Chantral
especially weatherchazer3 and scienceman i'm glad it's over
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1225. Patrap
TS Chantal

Dvorak Loop

Member Since: July 3, 2005 Posts: 421 Comments: 127664
Quoting 1218. RTSplayer:


Have they even made a pass on the south side of the previous alleged center fix from the last advisory?

All I saw was they came in from the NE, and then instead of penetrating straight through, they did a 90 to the NW and then went east a few degrees and came back down at about a 60 degree angle from the NW. They never even made it to the alleged center fix, and the real center was probably south of that.


they have not.. and that's information that is valuable
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(singing)..it's just a shift to the west and a jump to the north....

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
729 PM EDT TUE JUL 9 2013

TROPICAL SYSTEMS...
TROPICAL STORM CHANTAL IS CURRENTLY FORECAST BY THE NATIONAL
HURRICANE CENTER TO MOVE TO THE BAHAMAS THIS WEEKEND. AT THIS
TIME...TROPICAL STORM FORCE WINDS CANT BE RULED OUT FOR SOUTH
FLORIDA...PARTICULARLY OVER THE COASTAL AND METRO AREAS OF PALM BEACH COUNTY
ALONG WITH THE ATLANTIC WATERS OF SOUTH FLORIDA FOR SATURDAY.
RESIDENTS AND VISITORS SHOULD CONTINUE TO MONITOR THE LATEST
FORECAST FROM THE NATIONAL HURRICANE CENTER THROUGHOUT THE WEEK AND
INTO THE WEEKEND...AS THE WEATHER OVER SOUTH FLORIDA WILL DEPEND ON
THE LOCATION AND STRENGTH OF CHANTAL.
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Quoting 1192. Grothar:


Gro I am not liking that at all! It has her making landfall right over my house!
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1220. Patrap
Member Since: July 3, 2005 Posts: 421 Comments: 127664
Quoting 1209. bucyouup68:
Everything that comes off the African Coast seems to disappear, What gives?


It's still July ya know. Wait till mid-August and if you still have that complaint, then I will agree there's an issue.
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Quoting 1202. Patrap:
At 01:47:30Z (last observation), the observation was 171 miles (275 km) to the SSE (166°) from San Juan, Puerto Rico (USA)


Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 10th day of the month at 01:47Z
Date: July 10, 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: 19


01:47:30Z 16.017N 65.433W 842.5 mb
(~ 24.88 inHg) 1,622 meters
(~ 5,322 feet) 1015.7 mb
(~ 29.99 inHg) - From 140° at 42 knots
(From the SE at ~ 48.3 mph) 16.5°C
(~ 61.7°F) 15.0°C
(~ 59.0°F) 43 knots
(~ 49.4 mph) 34 knots
(~ 39.1 mph) 0 mm/hr
(~ 0 in/hr) 33.2 knots (~ 38.2 mph)
79.1%
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


Have they even made a pass on the south side of the previous alleged center fix from the last advisory?

All I saw was they came in from the NE, and then instead of penetrating straight through, they did a 90 to the NW and then went east a few degrees and came back down at about a 60 degree angle from the NW. They never even made it to the alleged center fix, and the real center was probably south of that.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
1217. hulakai
Station 42060
NDBC
Location: 16.332N 63.24W
Date: Wed, 10 Jul 2013 00:50:00 UTC

Winds: ESE (110°) at 19.4 kt gusting to 23.3 kt
Significant Wave Height: 12.5 ft
Dominant Wave Period: 9 sec
Mean Wave Direction: SE (137°)
Atmospheric Pressure: 30.00 in and rising
Air Temperature: 82.4 F
Dew Point: 74.7 F
Water Temperature: 82.4 F


Station 42059
NDBC
Location: 15.058N 67.528W
Date: Wed, 10 Jul 2013 00:50:00 UTC

Winds: NE (50°) at 15.5 kt gusting to 19.4 kt
Significant Wave Height: 5.2 ft
Dominant Wave Period: 7 sec
Mean Wave Direction: NE (55°)
Atmospheric Pressure: 29.96 in and rising
Air Temperature: 78.8 F
Dew Point: 75.6 F
Water Temperature: 82.9 F
Member Since: Posts: Comments:
Hello All! 1st post for the season and 1st time on wunderground... Been doing some reading on this blog which i find very diverse and very helpful on understanding these tropical systems... Can anyone provide a synopsis on whether south florida may see tropical force winds for the weekend or is to early to tell? We own an aviation business in miami and am contemplating moving our aircraft away from this thing...
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Quoting 1194. Hurricane12:


Which one is it?



It did shift west since this morning, why people fight and give themselves headaches after each one is insane, compare the mornings runs to tonights and there ya go.
Member Since: July 21, 2010 Posts: 0 Comments: 1083
1214. beell
I think a betting person would have to favor/consider a track over at least part of Cuba. Chantal is going to get disrupted to a certain extent over Hispaniola.

Chantal will probably get ripped up pretty good by shear getting across 20N. A shallow system should follow low-level steering and track farther west in a weak steering regime before the trough begins tugging it to the north.

And then, maybe the remnants tracking through the southern Bahamas and along the east coast of FL. And then back towards the coast towards the GA coast as the A/B ridge rebuilds. The upper trough will probably still be in place just inland of the east coast and extending back to the SW into the Gulf. Lower shear above 20N but still less than perfect.
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Quoting 1194. Hurricane12:


Which one is it?


I am looking at south Florida.
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Quoting 1198. moonlightcowboy:


Taz, right now it only shows about 20kts of shear if I'm reading the CIMSS chart correctly, which is not totally inhibiting, but probably accurately reflects Chantal not being able to build any significant cold tops right now. Plus, if I understand the anti-cyclonic flow, it's starting to tighten up a bit further west and making its way over Chantal too. At some point we may see a full overhead anti-cyclone over the system.

That's about as good as I can prognosticate at this point, my friend. Let's just keep the CAT 5's away, ok? ;P

Catch you later! :)



ok thank for the info
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Looks like Haiti to the Yucatan for the recurve.
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Quoting 1167. opal92nwf:

Wow. It was really compact when it made landfall. Many people said it wasn't as bad as Ivan. I assume those people weren't in the eyewall of Dennis. Because it was a major hurricane..
It was a small Hurricane and was moving at 20-25mph lasted about 2 to 3 hrs. I was in the eyewall of Ivan from 9:00pm to 9:00am.Dennis hit during the day Ivan at night I will take a day time Hurricane every Time!!
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Everything that comes off the African Coast seems to disappear, What gives?
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Quoting 1170. stormpetrol:
There is a center it's just not where they expected it to be! Its further south they need to fly around 14.5 N and well west of 65W, they'll find west winds.


Was just looking at the images and thinking around the same location but 14 N....just a very uneducated guess.
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Quoting 1203. cchsweatherman:
Hurricane Hunters are now moving southward. Should hopefully be entering the southern half of the storm where we should get the most important data either confirming or denying an organized tropical storm within the next half hour or so.


radar out of San Juan shows a pretty nice circulation
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Quoting 1193. Hurricanes305:
Where is Recon they should've been in the storm by now it they aree experiencing Instrument difficulties then by the time they go into the storm it maybe stronger.


They are in the storm, but for some reason they aren't looking in the right locations to find the center and closed low.

I don't know why they flew the route they did since it wasn't a very good clover shape like normal.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
1205. Patrap


Member Since: July 3, 2005 Posts: 421 Comments: 127664
Quoting 1162. cwf1069:
Hello everybody. Lurking most of the time. First entry this season. Chantal its giving a headache since the begining. Neither NHC and models know where she go. Looks like she's putting the brakes. LLC may be further down to the sw of the first path. Around 15n and 65.3


LOL how many times have we all heard these same phrases for every storm or hurricane on this blog over the years. Lets face if we could predict that a storm or hurricane 10 days out this blog would get boring as we would all know what will happen.
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Hurricane Hunters are now moving southward. Should hopefully be entering the southern half of the storm where we should get the most important data either confirming or denying an organized tropical storm within the next half hour or so.
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1202. Patrap
At 01:47:30Z (last observation), the observation was 171 miles (275 km) to the SSE (166°) from San Juan, Puerto Rico (USA)


Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 10th day of the month at 01:47Z
Date: July 10, 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: 19


01:47:30Z 16.017N 65.433W 842.5 mb
(~ 24.88 inHg) 1,622 meters
(~ 5,322 feet) 1015.7 mb
(~ 29.99 inHg) - From 140° at 42 knots
(From the SE at ~ 48.3 mph) 16.5°C
(~ 61.7°F) 15.0°C
(~ 59.0°F) 43 knots
(~ 49.4 mph) 34 knots
(~ 39.1 mph) 0 mm/hr
(~ 0 in/hr) 33.2 knots (~ 38.2 mph)
79.1%
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
Member Since: July 3, 2005 Posts: 421 Comments: 127664
Not liking the westward drift!
Quoting 1195. Patrap:




Stop it,yer scaring the dogs here.


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1200. hydrus
Quoting 1186. Grothar:
Really shifted west.

The blue track looks like the worst for Eastern Florida.
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Quoting 1169. Tazmanian:
this wind shear map is showing that chantal sould be under 20kts or higher wind shear but right now am starting too wounder if there is is some in thats keeping a way the high wind shear



Taz, right now it only shows about 20kts of shear if I'm reading the CIMSS chart correctly, which is not totally inhibiting, but probably accurately reflects Chantal not being able to build any significant cold tops right now. Plus, if I understand the anti-cyclonic flow, it's starting to tighten up a bit further west and making its way over Chantal too. At some point we may see a full overhead anti-cyclone over the system.

That's about as good as I can prognosticate at this point, my friend. Let's just keep the CAT 5's away, ok? ;P

Catch you later! :)
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Quoting 1176. moonlightcowboy:


;P I said I was going to be quiet. LOL. I am. I'm tired and have a long few days ahead. I'm thinking with that tongue of GoM high pressure, and with the Atlantic high filling in behind the ULL, we could see a blocking high with Chantal stuck, stalled, and having to find another route out - probably more westwards eventually in the GoM.

Yeah, ok, I've looked at loops, circles, and lines on a map too long. Y'all enjoy figuring this one out. She's a challenge, but I don't think she's going to Georgia! :)


Looks like more and more people agree with post #1053. (hee he)
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Send me an email... Catch me up!
Quoting 1179. CycloneOz:


Yep...directly underneath the ITCZ. It is both ironic and wonderful.

I evacuated the USA. It is unlikely I will ever return.
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1195. Patrap
Quoting 1186. Grothar:
Really shifted west.





Stop it,yer scaring the dogs here.


Member Since: July 3, 2005 Posts: 421 Comments: 127664
Quoting 1186. Grothar:
Really shifted west.

Quoting 1190. GeoffreyWPB:
A little shift to the east....



Which one is it?
Member Since: August 26, 2012 Posts: 0 Comments: 142
Where is Recon they should've been in the storm by now it they aree experiencing Instrument difficulties then by the time they go into the storm it maybe stronger.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
1192. Grothar
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What's up with the ULL off the southern tip of Florida? what happens it it moves toward Chantal...would it make Chantal move more east or go west underneath it?
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A little shift to the east....

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Quoting 1183. chrisdscane:



wishcasters are strong tonight boys, strap up.


How does concurring with the NHC make me a wishcaster?

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20+ inches of rain... Hoping they bloom tomorrow. Today was first real day of sun. I will take photos!
I am certainly watching the tropics, don't want another 20 inches anytime in the near future....
Quoting 1180. spathy:
Hi Beach.
With all that rain,are your rain Lilys blooming yet?
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Quoting 1163. Patrap:


Maybe the split model scenario gets cleared up tomorrow. Maybe Chantal starts acting like a historical norm storm, and the models get some sort of real fix on it.

I just don't expect a model to get the forecast right when the storm's stats are so atypical.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
1186. Grothar
Really shifted west.

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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.