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.

Sign In or Register Sign In or Register

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: 1233 - 1183

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

Quoting 1227. Tazmanian:
i think we sould see 96L soon

With the new African wave? It doesn't even have a yellow crayon around it yet
Member Since: Posts: Comments:
Time: 21:17:30Z
Coordinates: 11.7667N 54.7333W
Acft. Static Air Press: 966.4 mb (~ 28.54 inHg)
Acft. Geopotential Hgt: 395 meters (~ 1,296 feet)
Extrap. Sfc. Press: 1011.1 mb (~ 29.86 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 33° at 17 knots (From the NNE at ~ 19.5 mph)
Air Temp: 22.5°C (~ 72.5°F)
Dew Pt: 21.0°C (~ 69.8°F)
Peak (10s) Flt. Lvl. Wind: 18 knots (~ 20.7 mph)
SFMR Peak (10s) Sfc. Wind: 21 knots (~ 24.1 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
Member Since: Posts: Comments:
1230. Grothar
Quoting 1203. ProgressivePulse:
I am surprised at the model agreement in the longer range.


Yo, P. They all look like they want to go in the same direction.

Member Since: July 17, 2009 Posts: 71 Comments: 27519
1228. will40
now recon is updating
Member Since: September 19, 2005 Posts: 2 Comments: 4266
when a system is putting a hurting on a local community i like to listen to their music i think its a form of respect. http://www.youtube.com/watch?v=1befV_ai-Ls love this group a barbados one off a yatube
Member Since: Posts: Comments:
Quoting 1216. PalmBeachWeatherBoy:
When will warnings be issued for DR and haiti? I think the govt. in DR handles its own warnings...if I'm not mistaken.

Yes, the Dominican Republic issues their own watches/warnings... you can see that in the advisory when it says, "The government of the Dominican Republic has issued a Tropical Storm Watch for..." but as for when a warning is issued, I believe its the same standards as when the US issues watches/warnings
Member Since: Posts: Comments:
Yes they do!
Quoting 1214. hurricanewatcher61:
Does the Hurricane Center usally follow the TVCN model?
Member Since: Posts: Comments:
Timing of the Hunters is great as the sun is setting and we are losing the visible loops for the day.
Member Since: Posts: Comments:
1221. will40
Quoting 1213. MiamiHurricanes09:
Yeah, it's updating on the Tropical Atlantic website.

The NHC page is behind though, which is weird.

http://www.nhc.noaa.gov/text/URNT15-USAF.shtml

Edit: And it updated as soon as I made this post LOL.


still at 21:07:30Z here so may be prob with both sites
Member Since: September 19, 2005 Posts: 2 Comments: 4266
Quoting 1216. PalmBeachWeatherBoy:
When will warnings be issued for DR and haiti? I think the govt. in DR handles its own warnings...if I'm not mistaken.


yeah ----------->Link
Member Since: June 20, 2012 Posts: 0 Comments: 2178
Quoting 1200. RTLSNK:
It might be time to drop the adult themed jokes before
someone exceeds the community standards policy. Some
of you may want to talk about the storm. Thanks.

I agree, this is typical when we are all anticipating the latest updates especially from the HH, anything to quickly pass the time before all the data can be annualized and placed into the models, as soon as that happens it will be all business, believe me. The next set of models will provide some important additional information. I'm hoping this run will but some light on the TS trying to outrun it's cloud cover and thunderstorm activity. If this happens all eyes will shift right.
Member Since: Posts: Comments:
1217. Grothar
Quoting 1211. Dakster:


I know Grothar, you've been saying the same thing for 3 days now. You really did give a great call on this one.


Thanks, Dak.
Member Since: July 17, 2009 Posts: 71 Comments: 27519
When will watches be issued for DR and haiti? I think the govt. in DR handles its own warnings...if I'm not mistaken.

EDITED* TO WATCHES
Member Since: Posts: Comments:
1215. Dakster
Quoting 1206. MechEngMet:



Just because you disagree with me doesn't
make it a valid argument.

Yes it does, No it doesn't, Yes it does, No it doesn't,

Now see here!! I'm not here for an argument! Yes you are. No I'm not. yes...

-God bless Monty Python.


Sometimes I think this blog is stuck in a Monty Python episode.
Member Since: March 10, 2006 Posts: 0 Comments: 11290
Does the Hurricane Center usally follow the TVCN model?
Member Since: Posts: Comments:
Quoting 1210. will40:


last one i see is 21:07:30Z
Yeah, it's updating on the Tropical Atlantic website.

The NHC page is behind though, which is weird.

http://www.nhc.noaa.gov/text/URNT15-USAF.shtml

Edit: And it updated as soon as I made this post LOL.
Member Since: Posts: Comments:
Quoting 1200. RTLSNK:
It might be time to drop the adult themed jokes before
someone exceeds the community standards policy. Some
of you may want to talk about the storm. Thanks.


Roger that! Sorry..
Member Since: Posts: Comments:
1211. Dakster
Quoting 1193. Grothar:


Actually, I thought it read to the right, which would indicate a movement to the east. All the models seem to be acting like I thought they would. Moving across or over Hispaniola then through the Windward Passage and into the Bahamas. As Levi pointed out earlier, as the high moves back in, it could move whatever is left of Chantal strongly to the west.


I know Grothar, you've been saying the same thing for 3 days now. You really did give a great call on this one.
Member Since: March 10, 2006 Posts: 0 Comments: 11290
1210. will40
Quoting 1205. MiamiHurricanes09:
Recon data delayed.


last one i see is 21:07:30Z
Member Since: September 19, 2005 Posts: 2 Comments: 4266
1209. pcola57
Link for larger Image..

Member Since: Posts: Comments:
Quoting 1203. ProgressivePulse:
I am surprised at the model agreement in the longer range.
I agree.......For such a long way out it is pretty tightly grouped
Member Since: Posts: Comments:
1207. nigel20
Quoting GTstormChaserCaleb:
That is ok we can take a Tropical Storm, Haiti and Dominican Republic can't.

Hey Caleb!
The Dominican Republic is a lot more resilient to storms than 15-20 years ago. I don't think that a storm will cause much damage to Dom Rep. Infrastructure in the Dominican Republic has been on the improve over the last two decade, so too the economy.
Member Since: Posts: Comments:
Quoting 1198. Dakster:


Yes he IS, Yes he IS!!!!



Just because you disagree with me doesn't
make it a valid argument.

Yes it does, No it doesn't, Yes it does, No it doesn't,

Now see here!! I'm not here for an argument! Yes you are. No I'm not. yes...

-God bless Monty Python.
Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
I am surprised at the model agreement in the longer range.
Member Since: August 19, 2005 Posts: 5 Comments: 5460
Kind of funny when you take a break for a few hours and the same arguments/observations from this AM are repeated by the PM crew...........Even from some of 24/7 folks even though not much has changed from this morning (except the storm having booked a few hundred miles)............. :)

Member Since: Posts: Comments:
1200. RTLSNK
It might be time to drop the adult themed jokes before
someone exceeds the community standards policy. Some
of you may want to talk about the storm. Thanks.
Member Since: Posts: Comments:
TVCN is on board with the trough not being strong enough to pull whatever remains of Chantal out to sea after making its way through the Bahamas


Member Since: August 19, 2005 Posts: 5 Comments: 5460
1198. Dakster
Quoting 1188. MechEngMet:


No he's not! ;p


Yes he IS, Yes he IS!!!!
Member Since: March 10, 2006 Posts: 0 Comments: 11290
..HH beginning to report observations from near-surface as they begin to fully enter T.S. CHANTAL..
Member Since: Posts: Comments:
1196. K8eCane
Quoting 1192. GTstormChaserCaleb:
Or if it will hit the Carolinas?


no you DIHENT
Member Since: Posts: Comments:
Time: 20:57:00Z
Coordinates: 12.5667N 55.45W
Acft. Static Air Press: 966.8 mb (~ 28.55 inHg)
Acft. Geopotential Hgt: 401 meters (~ 1,316 feet)
Extrap. Sfc. Press: 1012.3 mb (~ 29.89 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 45° at 25 knots (From the NE at ~ 28.7 mph)
Air Temp: 22.4°C (~ 72.3°F)
Dew Pt: 21.7°C (~ 71.1°F)
Peak (10s) Flt. Lvl. Wind: 27 knots (~ 31.0 mph)
SFMR Peak (10s) Sfc. Wind: 31 knots (~ 35.6 mph)
SFMR Rain Rate: 4 mm/hr (~ 0.16 in/hr)
(*) Denotes suspect data

Interesting surface winds for being on the NW side.
Member Since: April 29, 2007 Posts: 0 Comments: 8134
1194. Dakster
Quoting 1183. presslord:
Wonder if Chantal will have a substantial enough COC to pump the ridge?


Hey Press - How's Portlight doing? I have a feeling your services may unfortunately, be needed again quite soon.
Member Since: March 10, 2006 Posts: 0 Comments: 11290
1193. Grothar
Quoting 1153. Dakster:


No, same old arguments.

What do you think about the models trending towards the west?


Actually, I thought it read to the right, which would indicate a movement to the east. All the models seem to be acting like I thought they would. Moving across or over Hispaniola then through the Windward Passage and into the Bahamas. As Levi pointed out earlier, as the high moves back in, it could move whatever is left of Chantal strongly to the west.
Member Since: July 17, 2009 Posts: 71 Comments: 27519
Quoting 1183. presslord:
Wonder if Chantal will have a substantial enough COC to pump the ridge?
Or if it will hit the Carolinas?
Member Since: Posts: Comments:
Will Chantal be strong enough to feel the weakness..That's the question..
Member Since: Posts: Comments:
Quoting 1187. K8eCane:
I liked the models at 12Z. Please don't take offense Fla
That is ok we can take a Tropical Storm, Haiti and Dominican Republic can't.
Member Since: Posts: Comments:


Recon getting close!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Quoting 1176. mikatnight:


I believe you're looking for the Argument Blog.


No he's not! ;p
Member Since: Posts: Comments:
1187. K8eCane
I liked the models at 12Z. Please don't take offense Fla
Member Since: Posts: Comments:
1186. Levi32
Transit leg is over. Plot is now reset for near-surface observations. Plane is entering western-most spiral band of Chantal.

Recon data plots

Member Since: November 24, 2005 Posts: 635 Comments: 26731
1185. pcola57
Quoting 1183. presslord:
Wonder if Chantal will have a substantial enough COC to pump the ridge?


**Edited due to mod comment
Member Since: Posts: Comments:
Wonder if Chantal will have a substantial enough COC to pump the ridge?
Member Since: Posts: Comments:

Viewing: 1233 - 1183

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.

JeffMasters's Recent Photos

Carrot Nose in Danger
Deep Snow in Brookline, MA
Sunset at Fort DeSoto
New Years Day Sunset in Death Valley