Tropical Storm Chantal: a Likely Harbinger of an Active Atlantic Hurricane Season

By: Dr. Jeff Masters , 2:02 PM GMT on July 08, 2013

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Tropical Storm Chantal is speeding westwards at 26 mph towards a Tuesday encounter with the Lesser Antilles Islands. Satellite loops show that Chantal has plenty of spin, with several well-developed low-level spiral bands that have gradually increased their heavy thunderstorm activity this morning. However, Chantal is fighting dry air associated with the Saharan Air Layer (SAL). The heavy thunderstorm activity near Chantal's center is rather thin, and there are virtually no heavy thunderstorms on the storm's north side, where upper-level northwesterly winds are creating light to moderate wind shear of 5 - 15 knots, and driving dry air into the storm. This dry air is readily apparent on water vapor satellite loops. Ocean temperatures are fairly warm, though, at 27.5 - 28°C. There have not been any hurricane hunter missions into Chantal yet, but an Air Force hurricane hunter aircraft deployed to St. Croix on Sunday, and is scheduled to investigate Chantal on Monday afternoon.


Figure 1. MODIS image of Chantal taken at approximately 10 am EDT Monday, July 8, 2013. At the time, Chantal had top winds of 45 mph. Image credit: NASA.


Figure 2. U.S. Air Force Master Sgt. Levi Denham, a WC-130J Hercules aircraft weather reconnaissance loadmaster assigned to the 53rd Reconnaissance Squadron (the Hurricane Hunters), performs pre-engine start-up inspections in St. Croix, Virgin Islands, on Sept. 16, 2010. DoD photo by Staff Sgt. Manuel J. Martinez, U.S. Air Force. Thanks go to wunderground member Patrap for pointing out this photo.

Forecast for Chantal
The 8 am EDT Monday forecast from the SHIPS model predicts that Chantal will experience low to moderate shear through Tuesday afternoon as it heads west-northwest at 25 mph towards Hispaniola. With ocean temperatures expected to warm to 28°C during that time, Chantal has the potential to intensify to a 65 mph tropical storm before hitting Hispaniola. Working against intensification will be 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, and I don't see Chantal making it to hurricane strength before interacting with the mountains of Hispaniola and/or Cuba on Tuesday night and Wednesday. This interaction may be able to destroy the storm, since wind shear is also expected to rise to the high range, 20 - 30 knots, Tuesday night through Thursday. Chantal has the potential to cause big problems for Haiti, which is highly vulnerable to flash flooding due to the lack of vegetation on the deforested mountains. However, there is a lot of dry air to the west of Chantal, which may act to keep rainfall totals in Haiti down to a manageable 2 - 4". Over 300,000 people are still homeless and living in makeshift tent camps in Haiti, three years after the great 2010 earthquake.

Once Chantal crosses Hispaniola and enters the Bahamas late this week, the trough of low pressure pulling the storm to the northwest is expected to lift out. It is unclear at this point whether or not this trough will be strong enough to pull Chantal out to sea, or whether the storm might be forced back to the northwest into the U.S. East Coast by high pressure building in.


Figure 3. There have been only thirteen tropical depressions or tropical storms that have formed July 15 or earlier that have passed through the Lesser Antilles since 1851, an average of one such tropical cyclone every thirteen years. Note that two of these storms, Dennis and Emily, occurred during the notorious Hurricane Season of 2005. There were five other pre-July 16 storms that formed east of the Lesser Antilles Islands, but did not pass through the islands (Bertha of 2009, Barry of 1989, and unnamed tropical depressions in 1967, 1978, and 2001.) Image credit: NOAA's Historical Hurricane Tracks website.

Chantal: an uncommon early-season Cape Verde-type tropical storm
Formation of a tropical storm east of the Lesser Antilles Islands in early July from an African tropical wave is an uncommon occurrence. Since Atlantic hurricane records began in 1851, there have been only thirteen tropical depressions or tropical storms that have formed July 15 or earlier that have passed through the Lesser Antilles, an average of one early-season tropical cyclone every thirteen years. Note that two of these storms, Dennis and Emily, occurred during the notorious Hurricane Season of 2005. There were five other pre-July 16 storms that formed east of the Lesser Antilles Islands, but did not pass through the islands (Bertha of 2009, Barry of 1989, and tropical depressions in 1967, 1978, and 2001 that did not become named storms.)

Chantal: a likely harbinger of an active Atlantic hurricane season
Chantal's formation on July 8 is an usually early date for formation of the season's third storm, which usually occurs on August 13. A large number of early-season named storms is not necessarily a harbinger of an active season, unless one or more of these storms form in the deep tropics, south of 23.5°N. According to Phil Klotzbach and Bill Gray, leaders of Colorado State's seasonal hurricane forecasting team,

"Most years do not have named storm formations in June and July in the tropical Atlantic (south of 23.5°N); however, if tropical formations do occur, it indicates that a very active hurricane season is likely. For example, the seven years with the most named storm days in the deep tropics in June and July (since 1949) are 1966, 1969, 1995, 1996, 1998, 2005, and 2008. All seven of these seasons were very active. When storms form in the deep tropics in the early part of the hurricane season, it indicates that conditions are already very favorable for TC development. In general, the start of the hurricane season is restricted by thermodynamics (warm SSTs, unstable lapse rates), and therefore deep tropical activity early in the hurricane season implies that the thermodynamics are already quite favorable for tropical cyclone (TC) development."

Two of this season's three storms have formed in the deep tropics--Tropical Storm Barry, which formed in the Gulf of Mexico's Bay of Campeche at a latitude of 19.6°N, and now Tropical Storm Chantal, which formed at a latitude of 9.8°N. With recent runs of the GFS model predicting formation of yet another tropical storm southwest of the Cape Verde Islands early next week, it appears that the Atlantic is primed for an active hurricane season in 2013.

Jeff Masters

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12z Navgem takes whats left of Chantal up the west coast of Florida into the panhandle..
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Quoting 574. weatherlover94:
I believe we should worry more about future Dorian than Chantel
What about Chantal?
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My guess for 2:00 update will be 45 mph ...there is a small chance for an increase to 50 mph but I think that will come after the hurricane hunters check it out
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Quoting 574. weatherlover94:
I believe we should worry more about future Dorian than Chantel

Ignored.
Member Since: July 2, 2013 Posts: 0 Comments: 1523
2 PM TWO about Upper Low.

A VIGOROUS UPPER-LEVEL LOW IS PRODUCING A LARGE AREA OF DISTURBED
WEATHER ACROSS THE CENTRAL AND SOUTHERN BAHAMAS AND ADJACENT
ATLANTIC WATERS. THERE ARE NO SIGNS OF A SURFACE CIRCULATION AND
PRESSURES ARE HIGH IN THE AREA. THIS SYSTEM HAS A LOW CHANCE...
NEAR 0 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT
48 HOURS AS IT MOVES WESTWARD AT 10 TO 15 MPH. HOWEVER...THIS
DISTURBANCE WILL PRODUCE PERIODS OF LOCALLY HEAVY RAINFALL AND
GUSTY WINDS ACROSS THE BAHAMAS THROUGH TOMORROW MORNING...AND
ACROSS PORTIONS OF THE SOUTHERN FLORIDA PENINSULA ON TUESDAY AND
WEDNESDAY.
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Chantal looks likes its growing in size...or maybe its just the convection firing out ahead of it.
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Quoting 570. hurricane23:
12z canadian is right into those cuban mountains then rides it up the florida eastocast. Sure
What do you think that ULL currently over the Bahamas will do to it in terms of track?
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Quoting 410. nrtiwlnvragn:
Same model, different computers..... you decide

They both have a ridge over me so they are the same. QED
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I believe we should worry more about future Dorian than Chantel
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Quoting 566. hurricane23:


Dont see much relaxation in those winds if it ever makes it into the southern bahamas.


Hey 23...........That would be a good thing.
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There is still a chance it could move north of the mountainous islands or thread the middle between Cuba and Hati ..or just go north of it all And charge straight for the US like Irene did however I don't think Chantel will be as strong as Irene , maybe a TS
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There is still a chance it could move north of the mountainous islands or thread the middle between Cuba and Hati ..or just go north of it all And charge straight for the US like Irene did however I don't think Chantel will be as strong as Irene , maybe a TS
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12z canadian is right into those cuban mountains then rides it up the florida eastocast. Sure
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Oh absolutely. I work for a tour company, definitely have to be safer than normal anyway just for that reason. I seem to be struggling with posting youtube videos on here. Oh well :p
Quoting sar2401:


Your YouTube video links don't show up properly in you post. That was a terrible day in El Reno. As has been said, if those three pros can get it, anyone can, so don't try for the absolute "best" shot out there.

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Chantal is currently fighting just to stay alive. The Upper Level Low in the Bahama's look's like it really means business when it passes over South Florida. This is one of the strongest ULLs I've seen in many years. Look's more like a Tropical Storm then Chantal does.
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Quoting tornadodude:
It's been a long and very eventful storm chasing season. My apartment was spared by 7 miles from the Moore ef5 tornado. I lost 3 friends to the El Reno tornado 11 days later.

However, I also witnessed some of the craziest weather I will probably ever see.

I saw my 55th tornado a couple of weeks ago in Wyoming.

I now work for Extreme Tornado Tours (Storm chasing tour company owned by Reed Timmer, Dave Holder, and Kevin Barton).

Anyway, I was editing some of my footage from this season, and here is my video from the record 2.6 mile wide El Reno Tornado:

& nbsp;       & nbsp;       & nbsp;       & nbsp;       G et your own valid XHTML YouTube embed code


Your YouTube video links don't show up properly in you post. That was a terrible day in El Reno. As has been said, if those three pros can get it, anyone can, so don't try for the absolute "best" shot out there.
Member Since: October 2, 2004 Posts: 0 Comments: 16324
Quoting weathermanwannabe:
The critical period for Chantal, in terms of a US impact, will certainly depend on the brush with Hispanola-Cuba before she/it emerges into the Florida Straights/Bahamas as noted by several including Levi.

Too far out (5 days) to speculate as to what could happen but a viable circulation, if combined with a real relaxation in sheer and the warm waters in that Region/Gulf Stream area could make things a little more interesting in the long-term.

Again, a good drill for the folks in South Florida to take adequate preparations this season for what may come their way in August-September.


Dont see much relaxation in those winds if it ever makes it into the southern bahamas.
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Quoting 518. CycloneOz:


Yes! It is good to be back around.

I was unbanned back in May after some years.

Ecuador is my new home. I live up in the Andes Mountains now.




Sup Oz?
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Since it didn't post before, here you go!





El Reno Tornado
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Quoting 545. Stormchaser2007:
GFS Ensembles are on board with EATL development



If that pans out we could have one of the most unique season yet. CV season is a month early climatology is way out the window when a storm develops in EATL and stay west till the Caribbean you know the high wants to do damage. Please prepare for a long season.
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Quoting 521. interstatelover7166:
HH info should start coming in around 2 PM EDT, according to the good ol' NHC [Twitter feed]
Save this link if you haven't already did.
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Soulik is in the process of closing off a pretty large eyewall.
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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.4
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 08 JUL 2013 Time : 161500 UTC
Lat : 11:02:16 N Lon : 52:09:19 W


CI# /Pressure/ Vmax
3.4 /1001.0mb/ 53.0kt


Final T# Adj T# Raw T#
3.2 3.6 3.8
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Tropical Storm Chantal gained wind speed of 45 mph as of the 11am Advisory



Tropical Storm Advisories are up for the Lesser Antilles and Puerto Rico
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Quoting 540. congaline:
I think Chantal will slow down as it enters warmer waters and will undergo RI. RI will bring it to hurricane status and keep it on a more WNW trajectory, right into Cocoa Bch/Titusville area. That's my idea and I'm sticking to it! LOL!
That's fine with me as long as no one starts that " St. Aug./Jax area.." ya'll keep it right down there where it belongs..lol..
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This will be fun to watch.
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Just noting (below) that some vorticity is starting to show up at the 700mb level with the upper level low over the Bahamas; not a surface circulation but you can start to see the outline of some rotation at the lower levels on the vis satt loops due East of Andros Island.

Link
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Quoting 536. Chucktown:


The dry air may linger and not move as fast as the rest of the surrounding environment. This is why SAL can "hang around" for quite awhile and not move in tandem with a system. Read this if you get a chance. Two semesters of Remote Sensing back in college taught me enough about this. :)

Link


Thanks! I'm starting to read it now.
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Quoting 546. tornadodude:
It's been a long and very eventful storm chasing season. My apartment was spared by 7 miles from the Moore ef5 tornado. I lost 3 friends to the El Reno tornado 11 days later.

However, I also witnessed some of the craziest weather I will probably ever see.

I saw my 55th tornado a couple of weeks ago in Wyoming.

I now work for Extreme Tornado Tours (Storm chasing tour company owned by Reed Timmer, Dave Holder, and Kevin Barton).

Anyway, I was editing some of my footage from this season, and here is my video from the record 2.6 mile wide El Reno Tornado:



Your comment has great points as well as some sad ones, Matt.

If you got noticed by Timmer, then you have arrived! :)

I am retired...fully retired...from both work and storm chasing.

It is good that you can do both in your job.

Stay safe out there. If Tim, Paul & Carl can screw up, ANYONE can!
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Quoting 546. tornadodude:
It's been a long and very eventful storm chasing season. My apartment was spared by 7 miles from the Moore ef5 tornado. I lost 3 friends to the El Reno tornado 11 days later.

However, I also witnessed some of the craziest weather I will probably ever see.

I saw my 55th tornado a couple of weeks ago in Wyoming.

I now work for Extreme Tornado Tours (Storm chasing tour company owned by Reed Timmer, Dave Holder, and Kevin Barton).

Anyway, I was editing some of my footage from this season, and here is my video from the record 2.6 mile wide El Reno Tornado:

That's sad man you have my sympathies. Glad you are ok.
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It's been a long and very eventful storm chasing season. My apartment was spared by 7 miles from the Moore ef5 tornado. I lost 3 friends to the El Reno tornado 11 days later.

However, I also witnessed some of the craziest weather I will probably ever see.

I saw my 55th tornado a couple of weeks ago in Wyoming.

I now work for Extreme Tornado Tours (Storm chasing tour company owned by Reed Timmer, Dave Holder, and Kevin Barton).

Anyway, I was editing some of my footage from this season, and here is my video from the record 2.6 mile wide El Reno Tornado:

El Reno Tornado Video
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TS Chantal

Rainbow Lop

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Chantal is firing some thunderstorms closer to the center again. Let's see if they don't collapse this time.
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Quoting 542. TylerStanfield:

And would be the 5th full tropical forming storm, and no subtropical developments for 2013. A lot different from 2012 and 2011.


very foreboding for later once the thermodynamics improve and the SAL starts to go away
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Quoting 543. Hurricanes305:




Actually slowed down from 25 to around 20-23 mph and pulling convection over the tight LLC. Can't wait to see what Recon finds

Maybe, I dont know, 50 mph winds?
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.
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GFS Ensembles are on board with EATL development

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Quoting 540. congaline:
I think Chantal will slow down as it enters warmer waters and will undergo RI. RI will bring it to hurricane status and keep it on a more WNW trajectory, right into Cocoa Bch/Titusville area. That's my idea and I'm sticking to it! LOL!

NO
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Quoting 525. weatherh98:


just when its about to outrun itself....



Actually slowed down from 25 to around 20-23 mph and pulling convection over the tight LLC. Can't wait to see what Recon finds
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Quoting 538. weatherh98:


also would have 3 deep tropical developments

And would be the 5th full tropical forming storm, and no subtropical developments for 2013. A lot different from 2012 and 2011.
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so when the HH get a good fix on the center..more reliable data gets placed in the models, then we can see what will happen with Chantal..go ahead and cook your popcorn..its going to be a doozy..
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I think Chantal will slow down as it enters warmer waters and will undergo RI. RI will bring it to hurricane status and keep it on a more WNW trajectory, right into Cocoa Bch/Titusville area. That's my idea and I'm sticking to it! LOL!
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Hurricane Preparation 2013

It's time to dust off that family disaster plan, or in many cases, create one.

Keeping your family safe during a hurricane starts with proper planning. One in six Americans live along the eastern seaboard or the Gulf of Mexico, making hurricane preparation a must for many and their families.








Evacuation Considerations for the Elderly, Disabled and Special Medical Care Issues



Your Evacuation Plan


Disaster Supplies Kit


NOAA Alert Weather Radio's


"Think outside the Cone"
hurricanebuddy.com
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Quoting 537. TylerStanfield:
Last thing.
If this Next Cape Verde storm were to pan out, and we get Dorian out of it. That would mean, we still would have a whole half of July to go, and still have the possibility to get a 3rd Cape Verde Storm. That would be insane!


also would have 3 deep tropical developments
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Last thing.
If this Next Cape Verde storm were to pan out, and we get Dorian out of it. That would mean, we still would have a whole half of July to go, and still have the possibility to get a 3rd Cape Verde Storm. That would be insane!
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Quoting 519. BaltimoreBrian:


Why not? what propels a storm through the air around it and not with the air around it?


The dry air may linger and not move as fast as the rest of the surrounding environment. This is why SAL can "hang around" for quite awhile and not move in tandem with a system. Read this if you get a chance. Two semesters of Remote Sensing back in college taught me enough about this. :)

Link
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Quoting 523. tornadodude:


whoa, that's a little different than New Mexico



Hey Dude!

Only a little different. The altitude is about the same, and the culture is similar, too.

But the food is WAY different!

Ok...I've got to go now and see my girl friend at her store in town.

Hasta Luego! :)
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Quoting 525. weatherh98:


just when its about to outrun itself....
It's starting to gain latitude now.
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Quoting 517. BaltimoreBrian:



No to Francis and Jeanne. But to this I say YES. 15 days off the East Coast. The blog would EXPLODE.



Cracking me up Colonel..

we don't need anymore water in south Florida.. they are dumping a billion gallons of polluted water a day into the St. Lucie River right now... sooo, should a Ginney happen, I have to hope that the rain stays offshore..
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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.