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: 2486 - 2436

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

2486. LargoFl
my best guess is folks in florida had better keep a good eye on this storm, we all know just how much rain we have been getting the last few weeks..every day..now IF this system comes into florida..imagine the added rainfall it will bring...we surely do NOT need this system coming anywhere near us ...now texas does indeed need its rains..and its nice to see ( and its way early yet) but its nice to see several tracks now Going to texas..so texans this IS a slight chance you can get some of this...we'll see what the maps look like say friday..its way too early yet to tell where she is going....good luck over there
Member Since: Posts: Comments:
Did they forget the center fix, lol.
Member Since: Posts: Comments:
This is getting comical at this point
Member Since: Posts: Comments:
2483. RevInFL
Is Chantal strengthening again? Am I off the hook on the east central FL coast? I am just trying to understand what this little trickster is doing.
Member Since: Posts: Comments:
Quoting 2477. ProgressivePulse:


Vortex Data Message. It's the center fix that was found by the hurricane hunters.

Thanks
Member Since: Posts: Comments:
CoC is 16.6n and 72w
Member Since: Posts: Comments:
2480. WxLogic
Whattt... I take a break and now recon find something. I really thought she was gone but I guess she's playing a joke on us.
Member Since: Posts: Comments:
looks like they are heading back to Chantal

14:18:00Z 16.800N 71.767W 925.4 mb
(~ 27.33 inHg) 785 meters
(~ 2,575 feet)
Member Since: Posts: Comments:
I think Chantal was just playing possum.
Member Since: Posts: Comments:
Quoting 2472. CaptDanny:
What is a VDM


Vortex Data Message. It's the center fix that was found by the hurricane hunters.
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 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.


Great Post and Great analysis MLC. Enjoyed reading!! Going a second round. :)

SouthernIllinois/Natalie
Member Since: Posts: Comments:
large area of disturbed weather in the eastern tropical atlantic. there is some cyclonic turning with this wave. if we have to go with forward speed and track, it could get here for St Lucia carnival this weekend
Member Since: Posts: Comments:
Tips
Do not enter games of oneupmanship with trolls or bloggers you find to be annoying. You will be banned along side them, as your verbal jousts consume the space and time everyone else is sharing. If you come across a troll or another blogger whom you find to be irritating, please use the site reporting tools and your ignore list.



Member Since: Posts: Comments:
Quoting 2431. aislinnpaps:
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!

OMG. THANK YOU. *Licks Lips* I need the fuel this morning. And never have I had myself in such a conundrum with food. I mean I just don't know where to start!!??? Think the burrito and jalapeno corn cake may be for starters. Wow! :)

Natalie
Member Since: Posts: Comments:
What is a VDM
Member Since: Posts: Comments:
2470. RTLSNK
OK, I will say this one last time.

Talk about the storm, and not about each other.

Member Since: Posts: Comments:
2469. wxmod
North pole web cam today.

Member Since: Posts: Comments:
Quoting 2459. ricderr:


I see the NHC has the upper hand on this storm.....Haha....J/K!
Member Since: Posts: Comments:
Wonder why no VDM was issued. I wonder if they indeed found a closed circulation.
Member Since: Posts: Comments:
2466. gator23
Based on facts. It was way to early to call for a DC threat.
Member Since: Posts: Comments:

Member Since: Posts: Comments:
2464. ricderr
my map is better than yours rita :-)
Member Since: Posts: Comments:
2463. gator23
I didnt post that to troll or to anger anyone. I have been on this blog for a long time and I have noticed that people tend to have location bias when forecasting. I am guilty of it too which is why I try to overcome it. I have seen location bias a lot on this blog. Debby last years comes to mind.
Member Since: Posts: Comments:
Quoting 2453. washingtonian115:
The hypocrite speaks..


Quoting 2455. gator23:
You sure did...



Classy. :)
Member Since: Posts: Comments:
Mmmp I was judged and run down for saying I don't want Chantal to come to D.C which looked like a possibility if the trough was faster.Now you admitted that you have location bias your self after putting me down.
Member Since: August 14, 2010 Posts: 10 Comments: 17480
2460. SLU
There must have been gusts to over 80kts in Martinique.

Image and video hosting by TinyPic
Member Since: Posts: Comments:
2459. ricderr
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Fay, the "joke"















Member Since: Posts: Comments:
2456. DVG
FWIW Dept....Fay was interesting and illuminating to me for a couple reasons. First the strengthening over land ( Lake O ). The second was the ill defined circulation off Titusville. I remember much discussion about where the center was.

Chantal's current situation raises a question from me to those with knowledge. Hispaniola's topography...an ill defined vs a well defined storm and the effect on both. As I imperfectly recall, I seem to recollect Hispaniola's topography could be more easily overcome by a less defined storm.

Should my memory be well served on this, then my thought is that if conditions over the Bahamas permit, Chantal could prove to be more substantial a storm yet.
Member Since: Posts: Comments:
2455. gator23
You sure did...
Member Since: Posts: Comments:
Quoting 2450. SFLWeatherman:
I'm from FL but look at this, i do not see this going to TX




You can clearly see the weakness in between the two highs... It will pull whatever is left of Chantel north into Cuba.
Member Since: Posts: Comments:
The hypocrite speaks..
Member Since: August 14, 2010 Posts: 10 Comments: 17480
2452. beell
06Z GFS takes a weak 700mb circulation to Louisiana.
Member Since: Posts: Comments:
2451. gator23
I get your saying but my point is still valid.

Quoting 2447. ricderr:
Location bias is crazy on this blog. Im guilty of it too though.



yep...i predict every storm is coming to el paso


Member Since: Posts: Comments:
I'm from FL but look at this, i do not see this going to TX


Quoting 2444. gator23:
Interesting... it seems that folks from Florida are calling for a Florida landfall and folks int he Caymens/Texas are saying west. Location bias is crazy on this blog. Im guilty of it too though.
Member Since: Posts: Comments:
She might be alive for now but the question is for how much longer.
Member Since: Posts: Comments:
Quoting 2443. stormpetrol:
Recon headed back to base! Closed circulation found , mission completed.


Questionable, no VDM was issued.
Member Since: Posts: Comments:
2447. ricderr
Location bias is crazy on this blog. Im guilty of it too though.



yep...i predict every storm is coming to el paso


Member Since: Posts: Comments:
Texas maybe?.Shear is favorable in the gulf.
Member Since: August 14, 2010 Posts: 10 Comments: 17480
not much imfo coming out a martinique dang french
Member Since: Posts: Comments:
2444. gator23
Interesting... it seems that folks from Florida are calling for a Florida landfall and folks int he Caymens/Texas are saying west. Location bias is crazy on this blog. Im guilty of it too though.
Member Since: Posts: Comments:
Recon headed back to base! Closed circulation found , mission completed.
Member Since: Posts: Comments:
Quoting 2438. islander101010:
fay was really bad here ceiling were singing for two days and 25inches of rain the sewers were overflowing and spilling into the mosquito lagoon should of got ready of that name
Fay was a storm I will not soon forget.
Member Since: Posts: Comments:
2441. SLU
Chantal in Martinique
Member Since: Posts: Comments:
Quoting 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


Yeah, I see, she's moving WNW.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
fay was really bad here ceiling were singing for two days and 25inches of rain the sewers were overflowing and spilling into the mosquito lagoon should of got ready of that name
Member Since: Posts: Comments:
Couple of points to go with the discussion this morning: Several storms, notably Andrew & Katrina were written off coming into this same area. This is not to suggest that we are going to see that type of storm, just that the ability to regenerate from an almost open wave is well documented.

The second thing is if it does fall apart, the energy is still there, and the areas to be affected will get some awful rains, etc. When a system is open, the weather lasts longer, and is much messier. When it has spun up, the weather has a tendency to wrap around and move with the storm.
Member Since: Posts: Comments:
Out for a bit, back later.
Member Since: Posts: Comments:

Viewing: 2486 - 2436

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

Overcast
48 °F
Overcast