Unusual Chantal Disorganized, but has 65 mph Winds

By: Dr. Jeff Masters , 8:06 PM GMT on July 09, 2013

Share this Blog
72
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 2436 - 2386

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54Blog Index

Out for a bit, back later.
Member Since: Posts: Comments:
I'd say there's still a center (not a good one) but still one. NHC might not need to downgrade to T-wave.
Member Since: Posts: Comments:
this is a tropical wave now new update at 11am
Member Since: Posts: Comments:
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 are 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.



Hurricane Ernesto 2006 looks like a possible track.
Member Since: May 1, 2013 Posts: 0 Comments: 761
2432. SLU
Quoting 2411. Tropicsweatherpr:


Hi SLU. Yes,we have to watch the wave in the next few days. Maybe 96L soon. How did St Lucia did with the quick Chantal passage thru there?


Hey.

She was a complete anti-climax. Some parts of the island got higher gusts to TS force which threw down some trees and they lost power but overall, we are fine. Martinique got the hit. Some damage occurred there.

Member Since: Posts: Comments:
Good morning, afternoon and evening everyone. A warm 79 degrees this morning with a high of 95 expected later. A chance of rain again, but I'll believe that when I see it.

Breakfast's on the sideboard: breakfast burritos, huevos rancheros, Mexican omelets, jalapeno corn cakes, breakfast enchiladas, chorizo, donuts, fried ham, cinnamon oatmeal, yogurt and fresh fruit and orange juice, coffee - regular and decaf. Enjoy!
Member Since: Posts: Comments:
2430. GetReal
Quoting 2408. ProgressivePulse:
Should start to feel the weakness soon.




I do believe that Chantal, or whatever is left, will begin lifting more true WNW near the eastern tip of Jamaica and head towards the Florida Straits.
Member Since: Posts: Comments:
2429. gator23
She isnt moving due west really. More NW or WNW. Look at the forecast points. Also if you look at the steering layer she will begin to feel the weakness soon.

Steering: Link

Satellite with forecats points:Link

Quoting 2418. TylerStanfield:

Looks like they may find that she still has a circulation, but just very ill defined. 1013 Millibars with top winds no at 40 Mph.
She's barely holding on right now, but if she continues west, the Shear is only going to get worse, though trade winds will slow some. Land Interaction, Moderate-Strong Wind Shear, and Moderate Trade winds could still bring her down at this point.
Member Since: Posts: Comments:
Quoting 2417. stormpetrol:
Pressures are high, but enough data gathered to still support a 45-50mph TS.
do you think its still a tropical storm??
Member Since: Posts: Comments:
2427. Drakoen
Quoting 2408. ProgressivePulse:
Should start to feel the weakness soon.



May clip Haiti but moreso Cuba. Even if it were a tropical wave it would be inclined to move more poleward as that's what the low level flow dictates.
Member Since: Posts: Comments:
Wow, that is one weak set of W components. And she has Haiti/Cuba to look forward to?
Member Since: Posts: Comments:
Recon finding that there still is a ill-defined center with Chantal, but she may not be here for much longer, at this rate. Winds around 45 Mph with some barbs a little higher, but pressures are at 1013 MB and she is still gasping for air at this point.
Member Since: Posts: Comments:
2413. wunderkidcayman 2:00 PM GMT on July 10, 2013 +0
Quoting 2400. SouthernIllinois:

You been right this whole time Petrol. You, Rita, and GetReal.

Don't forget me too

Thanks, Moonlightcowboy also.
Member Since: Posts: Comments:
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.

Member Since: Posts: Comments:
It's obvious that Chantal isn't dead, not yet.

The upper level winds are relaxing, she's under some of the hottest water in the Atlantic basin, and the dry air is almost gone. What's left but the shear and a lot lower mountains to cross?

The way I look at it, she avoided the mountains of Hispaniola, so that's to her advantage, despite the temporary setback in development.

Her name origin(Post 1291) worries me.

She could become a mountain that is moved from one place to another as an underline to another argument.

I would watch this one very carefully.
Member Since: Posts: Comments:
Quoting 2410. FIUStormChaser:




I wonder if any of it is actually going to come ashore, or is it just going to hang out there and tease everyone?
Member Since: Posts: Comments:
2420. GetReal
Quoting 2400. SouthernIllinois:

You been right this whole time Petrol. You, Rita, and GetReal.



You know the old saying about blind squirrels and broken clocks???
Member Since: Posts: Comments:
Quoting 2334. tj175:



Glad I have accordion shutters here in Miramar. I use to put up the panels but they are a pain in the rear if you know what I mean.
You are so right... lol
Member Since: Posts: Comments:
Quoting 2370. Levi32:
Recon found the most pronounced wind shift yet, but pressures are 1013mb.


Looks like they may find that she still has a circulation, but just very ill defined. 1013 Millibars with top winds now at 45 Mph.
She's barely holding on right now, but if she continues west, the Shear is only going to get worse, though trade winds will slow some. Land Interaction, Moderate-Strong Wind Shear, and Moderate Trade winds could still bring her down at this point.
Member Since: Posts: Comments:
Pressures are high, but enough data gathered to still support a 45-50mph TS.
Member Since: Posts: Comments:
Are there any major Models now showing Chantal threading the Jamaica Cuba needle and staying south of Cuba?
Member Since: Posts: Comments:
morning

SLU you beat me to it. how was the weather by you. notice in the north of the island from marisule up had gust of about 50mph in squalls. looking at that area in the eatl, quite interesting.
Member Since: Posts: Comments:
2414. SLU
Amazing how this system has been able to maintain its circulation while moving westwards at 30mph. Incredible.

SHEAR (KT) 35 30 29 37 30 19 17 2 6 12 13 28 34
Member Since: Posts: Comments:
Quoting 2400. SouthernIllinois:

You been right this whole time Petrol. You, Rita, and GetReal.

Don't forget me too
Member Since: June 13, 2009 Posts: 2 Comments: 11829
If she gets out of the shear and the ULL ventilates, new ballgame.
Member Since: Posts: Comments:
Quoting 2389. SLU:
11n 28w



Hi SLU. Yes,we have to watch the wave in the next few days. Maybe 96L soon. How did St Lucia did with the quick Chantal passage thru there?
Member Since: Posts: Comments:
Quoting 2401. forecaster1:
The blob is heading towards WPB seems to have circulation east of Ft Lauderdale

"http://radar.weather.gov/ridge/radar.php?rid=AMX &product=N0Z&overlay=11101111&loop=yes " target="_blank">Link
Quoting 2401. forecaster1:
The blob is heading towards WPB seems to have circulation east of Ft Lauderdale

"http://radar.weather.gov/ridge/radar.php?rid=AMX &product=N0Z&overlay=11101111&loop=yes " target="_blank">Link


Member Since: May 1, 2013 Posts: 0 Comments: 761
Ironic, regardless of what the Hunters determine in the short-term, that Chantal or Artist Formerly Known as Chantal is still on track for a brush with Haiti from the looks of the loops.
Member Since: Posts: Comments:
Should start to feel the weakness soon.

Member Since: Posts: Comments:
Member Since: Posts: Comments:
re.2398:The convection around the coc at this time is a great display of updraft-vs-downdraft dominant convection in the tropics.

The northern ball of convection has more surface convergence and upper level outflow and would be 'healthy' tropical convection from a TC point of view.

The southern ball; Not so much. Lots of low level outflow/gust fronts/arc clouds point to downdrafts and collapsing convective cells. Not nearly as 'healthy'
.

Image:

Member Since: Posts: Comments:
Quoting 2378. A4Guy:


Fay was no joke. Much of the State received flooding rains - she was very slow moving, and crossed the state a few times.

Isaac (last yr) was also a vigorous trop storm. Reat the NHC reports...parts of SoFla had 50+ winds, and quite a bit of rain. Neither was a Wilma, for sure, but they were meaningful events for a lot of poeple.


I remember Fay well, and I have gone back and checked my records. The reported center was about 40 miles from us at its closest point (SW Florida), with reported winds of 55 knots. If it had not been on the news we never would have suspected that a storm existed.

The impact was much worse for northern Florida due to the heavy rains.
Member Since: Posts: Comments:

Quoting 2351. tj175:




Fay was a Joke, lol. We have rainstorms that are way worse here in South Florida than she was and Hurricane Georges was nothing but a rain and wind event for mainland South Florida with the Florida Keys getting the bulk of the action. The last big event that we had was Katrina and Wilma back in 2005.
Fay may have not had much wind, but she certainly wasn't a joke. There was widespread flooding in Florida and many people had severe damage to their homes.
Member Since: Posts: Comments:
2403. gator23
For this to remain a tropical storm and not an open wave you need to have a low level circulation. The HH have found a low level circulation

Quoting 2362. FIUStormChaser:


I'm a first year Meterology student, so I'm still learning, could you explain to me what does it mean?

Isn't it necessary to find west winds?
Member Since: Posts: Comments:
Remote sensing folks might like this link.
http://oceanexplorer.noaa.gov/okeanos/media/exstr eam/exstream_04.html
Member Since: Posts: Comments:
The blob is heading towards WPB seems to have circulation east of Ft Lauderdale

Link
Member Since: Posts: Comments:
See if we get a VDM soon.
Member Since: Posts: Comments:
The convection around the coc at this time is a great display of updraft-vs-downdraft dominant convection in the tropics.

The northern ball of convection has more surface convergence and upper level outflow and would be 'healthy' tropical convection from a TC point of view.

The southern ball; Not so much. Lots of low level outflow/gust fronts/arc clouds point to downdrafts and collapsing convective cells. Not nearly as 'healthy'.

These features are most visible on RGB floater images, IMO.
Member Since: Posts: Comments:
Chantal further south and west, I don't think she will have a problem with Hispaniola !
Member Since: Posts: Comments:
Quoting 2352. Grothar:
I've got to run. I hope it's good news. If not, you won't have old Grothar to kick around anymore. :)


Quoting 2339. Grothar:
Fay survived and so did Georges








And so will Grothar! Positive Mental Attitude (PMA) my man. You've got scores of newbies to amaze and astound yet!
Member Since: Posts: Comments:
I don't know why the GFS does this.It'll develop a system and then drop it.Just like it did with Andrea and Barry.
Member Since: Posts: Comments:
T.S. Fay impacted central Florida with flooding and damage as bad as any of the 2004 and 2005 hurricanes that crisscrossed the state. Speed Direction and Area all have an impact.
Chantal seems fast and disorganized with inconsistent thunderstorm activity so far. Keep it up.
Member Since: Posts: Comments:
Up the Spine of Florida

Member Since: May 1, 2013 Posts: 0 Comments: 761
Just waiting for NHC to update on Chantal now...
Member Since: Posts: Comments:
Looks like it may be tilted with height as well due to the shear.
Member Since: Posts: Comments:
2390. StormWx
Chantal following the XTRP model, most likely headed to Mexico.
Member Since: Posts: Comments:
2389. SLU
11n 28w

Member Since: Posts: Comments:
Time: 13:37:00Z
Coordinates: 16.0667N 71.5833W
Acft. Static Air Press: 968.9 mb (~ 28.61 inHg)
Acft. Geopotential Hgt: 401 meters (~ 1,316 feet)
Extrap. Sfc. Press: 1014.2 mb (~ 29.95 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 193° at 5 knots (From the SSW at ~ 5.8 mph)
Air Temp: 22.3°C (~ 72.1°F)
Dew Pt: 22.3°C (~ 72.1°F)
Peak (10s) Flt. Lvl. Wind: 8 knots (~ 9.2 mph)
SFMR Peak (10s) Sfc. Wind: 36 knots* (~ 41.4 mph*)
SFMR Rain Rate: 14 mm/hr* (~ 0.55 in/hr*)
(*) Denotes suspect data

Appears to be a closed circulation.
Member Since: Posts: Comments:
Time: 13:35:30Z
Coordinates: 16.1167N 71.65W
Acft. Static Air Press: 968.5 mb (~ 28.60 inHg)
Acft. Geopotential Hgt: 397 meters (~ 1,302 feet)
Extrap. Sfc. Press: 1013.5 mb (~ 29.93 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 358° at 7 knots (From the N at ~ 8.0 mph)
Air Temp: 22.2°C (~ 72.0°F)
Dew Pt: 22.1°C (~ 71.8°F)
Peak (10s) Flt. Lvl. Wind: 8 knots (~ 9.2 mph)
SFMR Peak (10s) Sfc. Wind: 46 knots (~ 52.9 mph)
SFMR Rain Rate: 10 mm/hr (~ 0.39 in/hr)
(*) Denotes suspect data
Member Since: Posts: Comments:
Quoting 2352. Grothar:
I've got to run. I hope it's good news. If not, you won't have old Grothar to kick around anymore. :)


You are strong and it will be good news. Check back in when you get home.
Member Since: Posts: Comments:

Viewing: 2436 - 2386

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Mostly Cloudy
73 °F
Mostly Cloudy