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

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

Share this Blog
95
+

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

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: 2883 - 2833

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 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70Blog Index

2883. nigel20
Quoting Dakster:


Interesting statistics. Thanks for sharing.

Here's to a remaining season of Fish storms. (if only that would work)

Yeah, no problem!
Member Since: Posts: Comments:
Quoting 2880. GTstormChaserCaleb:
I'm willing to bet they even have higher per capita than some places in the US. By the way RGB is showing Chantal weaker tonight as it is not as symmetrical as just even a few hours ago.


Do you think this will make it to the Gulf?
Member Since: Posts: Comments:
2881. hu2007
Quoting 2866. Dakster:


I agree.... And then there will always be another one after that. This is just July - August and September should be quite interesting.
it will be like hell august and septiembre
Member Since: Posts: Comments:
Quoting 2874. nigel20:

I live an island (Jamaica) as well and the overall residential (houses) as well as the road and bridge infrastructure is improving. You'll find most of the poor infrastructure in the squatter settlements where they tend not to follow the building codes.

It's very likely that the infrastructure in Barbados is superior to that in Jamaica. Barbados is the only country in the Caribbean with very high human development...They also have one the highest per capita income PPP in the Caribbean...in excess of US$20 000. I would assume that they have a better housing stock that most of the region.
I'm willing to bet they even have higher per capita than some places in the US. By the way RGB is showing Chantal weaker tonight as it is not as symmetrical as just even a few hours ago.

Member Since: Posts: Comments:
Chantal at 13.0N/13.1N 58.0W/58.1W via radar and Satellite
Member Since: Posts: Comments:
Quoting 2877. Dakster:


Interesting statistics. Thanks for sharing.

Here's to a remaining season of Fish storms. (if only that would work)


You were my friend.

Kidding. :P
Member Since: Posts: Comments:
2877. Dakster
Quoting 2874. nigel20:

I live an island (Jamaica) as well and the overall residential (houses) as well as the road and bridge infrastructure is improving. You'll find most of the poor infrastructure in the squatter settlements where they tend not to follow the building codes.

It's very likely that the infrastructure in Barbados is superior to that in Jamaica. Barbados is the only country in the Caribbean with very high human development...They also have one the highest per capita income PPP in the Caribbean...in excess of US$20 000. I would assume that they have a better housing stock that most of the region.


Interesting statistics. Thanks for sharing.

Here's to a remaining season of Fish storms. (if only that would work)
Member Since: Posts: Comments:
I think Chantale going to 60 mph soon.
Member Since: July 2, 2013 Posts: 0 Comments: 1307
2875. SLU
While Chantal's LLC is rather weak and ill-defined on satellite derived winds, it is still closed as one can see westerlies on the radar which only extend about 20 miles south of the center indicative of a very tight circulation. Besides, with 50kts winds barbs on OSCAT, the NHC will never downgrade to an open wave regardless with the system about to make landfall. What's most important now is the strength of the damaging winds and not the closed LLC. After it clears the islands then they will downgrade if needed.
Member Since: Posts: Comments:
2874. nigel20
Quoting Dakster:


I don't wish a storm on anyone - just thinking out loud that usually those islands are pretty resilient. They have to be, there is nowhere to run!

I live an island (Jamaica) as well and the overall residential (houses) as well as the road and bridge infrastructure is improving. You'll find most of the poor infrastructure in the squatter settlements where they tend not to follow the building codes.

It's very likely that the infrastructure in Barbados is superior to that in Jamaica. Barbados is the only country in the Caribbean with very high human development...They also have one the highest per capita income PPP in the Caribbean...in excess of US$20 000. I would assume that they have a better housing stock that most of the region.
Member Since: Posts: Comments:
Quoting 2865. AtHomeInTX:
EURO even has less love for Chantal this run. And has dropped the entire idea of Dorian. Lol. Couldn't find Pat's picture of the little guy saying "Nuttin'!"
The Euro seems to be in la la land it had the storm recurving up towards Bermuda the other day.
Member Since: Posts: Comments:
Quoting 2868. KoritheMan:


0z GFS had it about 175 miles south in the 10 - 14 day period, but keep in mind the GFS suffers from convective feedback/resolution issues beyond the 200 hour timeframe.
Yeah thats LA LA LAND! LOL Thats Like 300+ hours out i think
Member Since: Posts: Comments:
Quoting 2865. AtHomeInTX:
EURO even has less love for Chantal this run. And has dropped the entire idea of Dorian. Lol. Couldn't find Pat's picture of the little guy saying "Nuttin'!"


I really don't like the Euro for tropical cyclogenesis. I don't know why so many people do, lol.
Member Since: Posts: Comments:
Quoting 2861. Stormchaser2007:


I'm saying it's more than likely partially exposed and loosely organized. It may degenerate into an open wave eventually given the strong flow seen on satellite as well as observed at TBPB.

That's all.



That's been the same deal since day 1. She's moving 23-26, it's remarkable that she "IS" at this point and could open up an any time an nobody would be surprised.
Member Since: Posts: Comments:
Quoting KoritheMan:


SORRY ACCESS DENIED!!!..

KINDLY GO BACK TO BARBADOSWEATHER.ORG SATELLITE PAGE TO ACCESS SATELLITE IMAGERY

BBB Crawler Police...


What is this, I don't even...


Fixed lol

I'm out.
Member Since: Posts: Comments:
Quoting 2867. bigwes6844:
was there a model that shows Dorian south of LA?


0z GFS had it about 175 miles south in the 10 - 14 day period, but keep in mind the GFS suffers from convective feedback/resolution issues beyond the 200 hour timeframe.
Member Since: Posts: Comments:
Quoting 2860. KoritheMan:


Maybe. It'll be very interesting to see what implications on the track her possible dissipation into a tropical wave has for the Gulf Coast, if any.
was there a model that shows Dorian south of LA?
Member Since: Posts: Comments:
2866. Dakster
Quoting 2862. hu2007:
the one that is most likely to be more interesting is the wave coming out of africa and may be a stronger storm than chantal ever did by the time it gets the antilles ,stay tune for my simple but important comments. thanks


I agree.... And then there will always be another one after that. This is just July - August and September should be quite interesting.
Member Since: Posts: Comments:
EURO even has less love for Chantal this run. And has dropped the entire idea of Dorian. Lol. Couldn't find Pat's picture of the little guy saying "Nuttin'!"
Member Since: Posts: Comments:
Quoting 2863. Stormchaser2007:


Link


SORRY ACCESS DENIED!!!..

KINDLY GO BACK TO BARBADOSWEATHER.ORG SATELLITE PAGE TO ACCESS SATELLITE IMAGERY

BBB Crawler Police...


What is this, I don't even...
Member Since: Posts: Comments:
Quoting KoritheMan:


Those graphics are from WeatherBell, aren't they? lol


Link
Member Since: Posts: Comments:
2862. hu2007
the one that is most likely to be more interesting is the wave coming out of africa and may be a stronger storm than chantal ever did by the time it gets the antilles ,stay tune for my simple but important comments. thanks
Member Since: Posts: Comments:
Quoting ProgressivePulse:


So why was this not an open wave at 2am? Surely the next advisory will be?


I'm saying it's more than likely partially exposed and loosely organized. It may degenerate into an open wave eventually given the strong flow seen on satellite as well as observed at TBPB.

That's all.

Member Since: Posts: Comments:
Quoting 2855. bigwes6844:
Kori I have a feeling we may get something out of Chantal. Maybe not the center of it but at least some rain.


Maybe. It'll be very interesting to see what implications on the track her possible dissipation into a tropical wave has for the Gulf Coast, if any.
Member Since: Posts: Comments:
Quoting 2856. Stormchaser2007:


Satellite derived winds

Also, TBPB has winds out of the east @ 18 knots, so the flow is definitely strong.





Those graphics are from WeatherBell, aren't they? lol
Member Since: Posts: Comments:
Quoting 2856. Stormchaser2007:


Satellite derived winds

Also, TBPB has winds out of the east @ 18 knots, so the flow is definitely strong.





So why was this not an open wave at 2am? Surely the next advisory will be?
Member Since: Posts: Comments:
Quoting 2845. Stormchaser2007:


TRMM

Center is well north of the deep convection

ADT had this at 998mbs which is 12 millibars too high




Nevermind,I see it now,thanks.
Member Since: July 2, 2013 Posts: 0 Comments: 1307
Quoting KoritheMan:


Where do you figure?


Satellite derived winds

Also, TBPB has winds out of the east @ 18 knots, so the flow is definitely strong.



Member Since: Posts: Comments:
Quoting 2843. KoritheMan:


Yeah.
Kori I have a feeling we may get something out of Chantal. Maybe not the center of it but at least some rain.
Member Since: Posts: Comments:
2854. Dakster
Quoting 2841. bigwes6844:
u got da number still right?


867-5309?

-- Showing my age here --
Member Since: Posts: Comments:

Quoting 2836. Camille33:
If this storm was weakening it would be flagged.
Advanced Dvorak Technique isnt really to be trusted in terms of intensity, the weakening flag has gone off and on all day.
Member Since: Posts: Comments:
I still think this thing is TX bound after FL.
Member Since: Posts: Comments:
GFDL:

Member Since: Posts: Comments:
Quoting 2840. Stormchaser2007:


The center isn't close to the center of the convection. It's struggling at best right now with the winds at 1000-850mb around 20 knots.

The amount of stable air on the western side of the circulation certainly isn't helping.


According to the 2am she's still riding the western edge as she has been for some time now. Ripping apart is 100+ miles or so apart. I see nothing different from this afternoon except an increase in storms.
Member Since: Posts: Comments:
2849. Dakster
Quoting 2826. nigel20:

Hey Dakster! I know that the infrastructure in Barbados is a lot better than that of many Caribbean islands, so a TS would not be much of a problem...they've not had a direct hit from an hurricane for sometime now...I think the last one Allen in 1980, so a strong hurricane may pose a serious threat to their infrastructure..


I don't wish a storm on anyone - just thinking out loud that usually those islands are pretty resilient. They have to be, there is nowhere to run!
Member Since: Posts: Comments:
Microwave certainly not impressive:



A similar signature seems evident to me on shortwave infrared satellite loops as well. It may be that Chantal tries to tuck back underneath the convection where conditions are better and sharpen up her already ill-defined center, but it's equally possible she just dissipates.
Member Since: Posts: Comments:


Member Since: Posts: Comments:
Quoting 2840. Stormchaser2007:


The center isn't close to the center of the convection. It's struggling at best right now with the winds at 1000-850mb around 20 knots.

The amount of stable air on the western side of the circulation certainly isn't helping.


Where do you figure?
Member Since: Posts: Comments:
Quoting Camille33:

It is getting stronger per adt...your comment has 0 proof.


TRMM

Center is well north of the deep convection

ADT had this at 998mbs which is 12 millibars too high



Member Since: Posts: Comments:
2844. JLPR2
One last thing before I go...

There's Chantal!

More or less on 13.1N, 57.9W

Member Since: September 4, 2007 Posts: 7 Comments: 8483
Quoting 2841. bigwes6844:
u got da number still right?


Yeah.
Member Since: Posts: Comments:
Quoting 2833. Camille33:

It is getting stronger per adt...your comment has 0 proof.
But it must be closed in order to stay strong. Otherwise, nothing will be left in the morning.
Member Since: August 1, 2011 Posts: 28 Comments: 7890
Quoting 2827. KoritheMan:


We gonna keep in touch if need be, Wes? I expect a lot of texts from you! :D
u got da number still right?
Member Since: Posts: Comments:
Quoting ProgressivePulse:


I wouldn't go that far, why do you say that? Chantal looks to be organizing a bit tonight.


The center isn't close to the center of the convection. It's struggling at best right now with the winds at 1000-850mb around 20 knots.

The amount of stable air on the western side of the circulation certainly isn't helping.
Member Since: Posts: Comments:
2839. Skyepony (Mod)
Chantal has a recent TRMM pass. Click for a large movie..

Member Since: Posts: Comments:
On TPW you can clearly see chantal you can also see its recent westward turn
Member Since: Posts: Comments:
2837. hu2007
hiii, looks like chantal is having hard time keeping it self organize, moderate upper wnw winds is making the system disorganize, i think chantal have peak it intensity of 50 mph and from here out it may stay 50mph all day today and then start weakning starting tonight and in to wednesday, on to puerto rico , is looking better that chantal is small and all winds should stay south of pr, and lastly, it will not survive the shear and may turn more west in too the gulf if the system survive and turn in too a open wave. my forecast came from every source at hands.good morning
Member Since: Posts: Comments:
If this storm was weakening it would be flagged.
Member Since: July 2, 2013 Posts: 0 Comments: 1307
CI# /Pressure/ Vmax
3.5 / 998.8mb/ 55.0kt


Final T# Adj T# Raw T#
3.5 3.6 3.6

Center Temp : -41.1C Cloud Region Temp : -48.3C

Scene Type : CURVED BAND with 0.79 ARC in LT GRAY

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
Member Since: July 2, 2013 Posts: 0 Comments: 1307
2834. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #19
TYPHOON SOULIK (T1307)
15:00 PM JST July 9 2013
=============================

SUBJECT: Category Three Typhoon Named Cyclone In Sea East Of The Philippines

At 6:00 AM UTC, Typhoon Soulik (965 hPa) located at 19.8N 139.4E has 10 minute sustained winds of 70 knots with gusts of 100 knots. The cyclone is reported as moving west at 11 knots.

Storm Force Winds
==================
70 NM from the center

Gale Force Winds
===============
240 NM from the center

Dvorak Intensity: T4.5

Forecast and Intensity
=======================
24 HRS: 21.0N 134.6E - 80 knots (CAT 3/Strong Typhoon) South Of Japan
48 HRS: 22.1N 129.3E - 85 knots (CAT 4/Very Strong Typhoon) South Of Okinawa
72 HRS: 23.6N 124.5E - 90 knots (CAT 4/Very Strong Typhoon) South Of Okinawa
Member Since: Posts: Comments:
Quoting 2828. Stormchaser2007:
There probably won't be much left of Chantal by tomorrow morning if the trends continue.

Something is effectively ripping up the system

Oof


It is getting stronger per adt...your comment has 0 proof.
Member Since: July 2, 2013 Posts: 0 Comments: 1307

Viewing: 2883 - 2833

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 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70Blog 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.