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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2083. hu2007
well well we have a tropical warning,but my forecast is calling for 2 scenario.(1) if get above 60 mph a more wnw to nw should resume as early overnight during dmax (2) if get weaker should then continue a more west and even wsw and should die cause of the expected upper wsw shear from the upper low over bahamas, the most likely at this moment is the #1. i will keep my update from puerto rico and weather observation
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Chantal if she interacts with land interaction could look like Bonnie from 2010 who also had a ULL in it's vicinity.

Member Since: August 14, 2010 Posts: 10 Comments: 16725
2081. FOREX
Quoting 2065. HurricaneAndre:
Agreed.


Hopefully won't come near Panama City beach. We just had a lot of flooding.
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Quoting 2062. MiamiHurricanes09:
Overall trend seems to be a rightward shift with a sharp left turn in the long range.


BAMD looks to be the most realistic solution there.
/s
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hey folks... just tuning in..

was the discussion of why such a high pressure (1010 mb) for a 50 mph storm already had?...

this storm is very shallow
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Quoting 2062. MiamiHurricanes09:
Overall trend seems to be a rightward shift with a sharp left turn in the long range.



NHC has not gone with the left hand turn..... yet.
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Quoting 2062. MiamiHurricanes09:
Overall trend seems to be a rightward shift with a sharp left turn in the long range.




The two historical analogs which initially turned north then turned west and hit the east coast.


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2076. will40
Quoting 2072. HurricaneAndre:
I think that's old info.


look at C the date it leaves
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Quoting 2031. midgulfmom:
Sorry Tyler. Seriously hope someone can help. Clueless here. :(
Quoting 2032. BrowardJeff:

No problem. Yeah..the internet's a pretty cool place, if you know some of the tricks. :)

Glad I could give something back, since normally all I do is lurk and read people's forecasts..like yours.


ETA: It's really true that once it's on the internet, it's impossible to delete it. :)
Quoting 2035. lostinohio:
Tyler ------does this help?
http://web.archive.org/web/20130621225040/http:// www.wunderground.com/blog/TylerStanfield/show.html

Thanks for all the help guys... I got my 2013 Hurricane Season blog back :)
I might just say to hell with the other two... They were only about Andrea and Barry and a June/July Outlook... Not as big of a deal. :P
Member Since: June 2, 2013 Posts: 8 Comments: 1219
2074. GetReal



Very impressive expansion in size over the past 12 hours. Chantal is putting the weight on!!!
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Quoting 2052. weatherlover94:
Ships model now forecasts an 82 mph Hurricane heading for Florida in 5 days
Is that all?
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Quoting 2066. will40:


I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM CHANTAL
FLIGHT ONE -- TEAL 72 FLIGHT TWO -- TEAL 70
A. 10/0000Z,0600Z A. 10/1200Z,1800Z
B. AFXXX 0303A CHANTAL B. AFXXX 0403A CHANTAL
C. 09/2300Z C. 10/1100Z
D. 15.2N 64.1W D. 16.8N 68.2W
E. 09/2330Z TO 10/0600Z E. 10/1130Z TO 10/1800Z
F. SFC TO 10,00 FT F. SFC TO 10,000 FT
I think that's old info.
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Quoting 2062. MiamiHurricanes09:
Overall trend seems to be a rightward shift with a sharp left turn in the long range.



I don't like that path through GA... we don't need a drop of rain for a while...

meh... me complaining!
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Chantal: "I think I can", "I think I can"...

THE LITTLE STORM THAT COULD :)
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Quoting 2047. AussieStorm:


@BTSmith1 Brando
@spann awesome water spout in Clearwater, FL
That's in the Oldsmar/Safety Harbor area. Very nice area. Cool shot!
Member Since: June 30, 2013 Posts: 12 Comments: 8059
Quoting 2064. wxchaser97:

By going with a blend between SAB, TAFB, and UW-CIMSS ADT, I think it's at 50mph.

IIRC, recon goes back out tomorrow, though I wish they would've stayed in Chantal longer tonight.
what time.
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2066. will40
Quoting 2053. HurricaneAndre:
When will the next recon go out.I think it is now a 60 mph storm now.What do you think.


I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM CHANTAL
FLIGHT ONE -- TEAL 72 FLIGHT TWO -- TEAL 70
A. 10/0000Z,0600Z A. 10/1200Z,1800Z
B. AFXXX 0303A CHANTAL B. AFXXX 0403A CHANTAL
C. 09/2300Z C. 10/1100Z
D. 15.2N 64.1W D. 16.8N 68.2W
E. 09/2330Z TO 10/0600Z E. 10/1130Z TO 10/1800Z
F. SFC TO 10,00 FT F. SFC TO 10,000 FT
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Quoting 2062. MiamiHurricanes09:
Overall trend seems to be a rightward shift with a sharp left turn in the long range.

Agreed.
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Quoting 2053. HurricaneAndre:
When will the next recon go out.I think it is now a 60 mph storm now.What do you think.

By going with a blend between SAB, TAFB, and UW-CIMSS ADT, I think it's at 50mph.

IIRC, recon goes back out tomorrow, though I wish they would've stayed in Chantal longer tonight.
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2063. whitewabit (Mod)
To contact support its at the very bottom of the page under Contact us you will see Support .. click it and then its at the very top right of the page ..

Hope that helps !!
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Overall trend seems to be a rightward shift with a sharp left turn in the long range.

Member Since: September 2, 2009 Posts: 130 Comments: 21102
2061. Gearsts
Quoting 2026. Relix:
AL, 03, 2013070900, , BEST, 0, 120N, 550W, 45, 1010, TS
More north
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Quoting 2052. weatherlover94:
Ships model now forecasts an 82 mph Hurricane heading for Florida in 5 days

...without land interaction.

Given its interaction with Hispaniola, the SHIPS forecasts a 59 kt (68 mph) tropical storm.
Member Since: July 6, 2010 Posts: 113 Comments: 31862
Quoting 2010. TropicalAnalystwx13:
Huge disagreement within the GFS ensembles for the surface pressure in 10 days, located over or just north of the northeastern Caribbean. Means some ensembles depict a significant tropical cyclone.



East Coast may have to watch out, but that's a long way out (and note the eastern Atlantic lighting up again):



...and I find it funny how only one GFS ensemble shows a system near Jamaica in 15 days, but it is apparently very strong because of the significant disruption in the surface pressure field:



do you have some specific model images of the possible 'dorian' and/or 'erin'?
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Quoting 2034. FIUStormChaser:
Hey everyone, I have been busy studying for my summer B midterms. But I just wanted to come in and check on you guys and Chantal. Unfortunately Haiti is still in the forecast cone and we all know the dreadful situation that has been ongoing in that country since the major earthquake, with any type of system weak or small their are major landslides and to be quiet honest it does not take that high of a wind to collapse a tent. Anyways, It is also unfortunate that it looks like Florida is still in the cone, I expected to see a shift towards the left or right, but I assume because of the forward speed of this storm, the models will have a hard time reading the outcome. Earlier I finished removing excess debris from my back yard and just checking on the overall condition of my house.

For a storm to across the Atlantic this fast in July is very interesting, and the path it will take will be an indication of what could possibly be to come.



For all of you in the Islands in harms way:


And for those of you in the United States who do not recognize the existent of the Islands of the Carribean:



- FIUStormChaser
A noble and very thoughtful post...+1000!
Member Since: June 30, 2013 Posts: 12 Comments: 8059
Updated...

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2056. Thrawst
Quoting 2048. SFLWeatherman:


MAHAHA Chantal doesn't like the Northwest Bahamas ;)
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2055. vis0
i wonder (sadly) if anyone has the © for "stronger than the stormS"
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When will the next recon go out.I think it is now a 60 mph storm now.What do you think.
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Ships model now forecasts an 82 mph Hurricane heading for Florida in 5 days
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2051. Thrawst
Quoting 2041. AussieStorm:


28storms.com
The pics keep on coming..waterspout near Tampa Bay, FL (via Anne-Marie Filipinski-Townes) ‎#flwx


Okay I have to admit that picture is pretty freaking awesome.
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Quoting 2046. eyewallblues:
Chantal will go down as he brave soul who paved the way for Hurricane Dorian and Major Hurricane Erin.


Thanks for your take, you could be right, but so could I!
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Quoting 2046. eyewallblues:
Chantal will go down as he brave soul who paved the way for Hurricane Dorian and Major Hurricane Erin.
The major hurricane that is depicted by the models is "Dorian"
Member Since: August 14, 2010 Posts: 10 Comments: 16725
Member Since: May 23, 2012 Posts: 0 Comments: 4456


@BTSmith1 Brando
@spann awesome water spout in Clearwater, FL
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Quoting 2033. stormpetrol:


Yep I realised that right after I posted it and posted below to correct, Chantal will pass just south of Barbados IMO and maybe even south of Jamaica, what's your take?
Chantal will go down as he brave soul who paved the way for Hurricane Dorian and Major Hurricane Erin.
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Member Since: May 23, 2012 Posts: 0 Comments: 4456
Quoting 2038. eyewallblues:
Im getting a little worried about Dorian. Shes barely at 6.5 North! Needs to move up a degree or 2 soon. That being said, pre-Erin looks gorgeous!

It may turn out that the troll who projected 24-14-8 is exactly right.
You mean pre Dorian? and I assume your talking about Chantal.
Member Since: August 14, 2010 Posts: 10 Comments: 16725
to the missing blog guy, save a copy of everything on your computer. the amount of space to save a word doc and the images you use has to be small in comparison to all of my photo and design work.
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Quoting 2038. eyewallblues:
Im getting a little worried about Dorian. Shes barely at 6.5 North! Needs to move up a degree or 2 soon. That being said, pre-Erin looks gorgeous!

It may turn out that the troll who projected 24-14-8 is exactly right.

We already have Dorian? Pre-Erin?

And we won't get that high of numbers, and not even 2005 had that many majors.
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28storms.com
The pics keep on coming..waterspout near Tampa Bay, FL (via Anne-Marie Filipinski-Townes) ‎#flwx
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2040. FOREX
Quoting 2033. stormpetrol:


Yep I realised that right after I posted it and posted below to correct, Chantal will pass just south of Barbados IMO and maybe even south of Jamaica, what's your take?


What is it that has the GFS making a sharp left turn into Florida? The Bermuda high?
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2039. Patrap
At 00:57:30Z (last observation), the observation was 111 miles (179 km) to the E (94°) from Bridgetown, Barbados

Product: Air Force High Density (HDOB) Message (URNT15 KNHC)
Transmitted: 9th day of the month at 00:56Z
Date: July 9, 2013
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 302)
Storm Number: 03
Storm Name: Chantal (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 40

00:57:30Z 12.983N 57.967W 392.9 mb
(~ 11.60 inHg) 7,736 meters
(~ 25,381 feet) - 424 meters
(~ 1,391 feet) From 68° at 24 knots
(From the ENE at ~ 27.6 mph) -18.0°C
(~ -0.4°F) -52.4°C
(~ -62.3°F) 24 knots
(~ 27.6 mph) - - - -
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: 423 Comments: 127804
Im getting a little worried about Dorian. Shes barely at 6.5 North! Needs to move up a degree or 2 soon. That being said, pre-Erin looks gorgeous!

It may turn out that the troll who projected 24-14-8 is exactly right.
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Meanwhile the ULL enters the frame.

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Meanwhile, 75mm of rain in Toronto today brings widespread flooding, closing the Don Valley Parkway, and shutting down parts of the TTC.

http://livenews.thestar.com/Event/Severe_thunders torms_in_Toronto
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Tyler ------does this help?
http://web.archive.org/web/20130621225040/http:// www.wunderground.com/blog/TylerStanfield/show.html
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Hey everyone, I have been busy studying for my summer B midterms. But I just wanted to come in and check on you guys and Chantal. Unfortunately Haiti is still in the forecast cone and we all know the dreadful situation that has been ongoing in that country since the major earthquake, with any type of system weak or small their are major landslides and to be quiet honest it does not take that high of a wind to collapse a tent. Anyways, It is also unfortunate that it looks like Florida is still in the cone, I expected to see a shift towards the left or right, but I assume because of the forward speed of this storm, the models will have a hard time reading the outcome. Earlier I finished removing excess debris from my back yard and just checking on the overall condition of my house.

For a storm to across the Atlantic this fast in July is very interesting, and the path it will take will be an indication of what could possibly be to come.



For all of you in the Islands in harms way:


And for those of you in the United States who do not recognize the existent of the Islands of the Carribean:



- FIUStormChaser
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Quoting 2023. wunderkidcayman:

kinda not really



someone hack you and you got screwed but check Admin/mods to help you for sure



they are climbing so its invalid


Yep I realised that right after I posted it and posted below to correct, Chantal will pass just south of Barbados IMO and maybe even south of Jamaica, what's your take?
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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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