Unprecedented Hurricane Tomas pounding the Lesser Antilles

By: Dr. Jeff Masters , 3:38 PM GMT on October 30, 2010

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Hurricane Tomas, an unprecedented Lesser Antilles hurricane for so late in the season, is bearing down on the islands of St. Lucia and St. Vincent with Category 1 winds of 75 mph. Recent radar imagery from the Martinique radar shows that Tomas is still in the organizing stage, with an eyewall that just closed off, and a weak area of echoes on the south side, due to modest wind shear of 10 knots caused by southerly upper-level winds. The Hurricane Hunters reported top surface winds in the northern eyewall near 75 mph. St.Lucia figures to get the worst blow from Tomas, as this island will experience the strong right-front quadrant of the storm--the north eyewall. Winds on the island were sustained at 46 mph, gusting to 67 mph, at 11am EDT. Winds at Barbados peaked at 37 mph, gusting to 56 mph, early this morning, and the pressure bottomed out at 994 mb. Satellite loops of Tomas show a large and well-organized Cape Verdes-type hurricane, with good upper level outflow on all sides except the south, and an impressive amount of heavy thunderstorm activity. This is a very dangerous hurricane that is just beginning to get going. You can follow the progress of Tomas through the islands today with our wundermap zoomed in on St. Lucia.


Figure 1. Morning radar image from the Martinique radar shows the eye of Tomas moving between the islands of St, Lucia to the north and St. Vincent and the Grenadines to the south. The southern portion of the eyewall had just closed off with this image. Image credit: Meteo France.

Intensity forecast for Tomas
Now that the eyewall of Tomas has completely closed off, a period of steady and possibly rapid intensification lasting until Sunday afternoon is likely. The intensification rate may then be slowed by an increasing flow of southwesterly upper-level winds, which are expected to bring dry air and a moderate 15 - 20 knots of wind shear to Tomas Sunday through Tuesday, according to the latest SHIPS model forecast. Shear is then expected to relent, allowing more intensification on Wednesday. Water temperatures are a record warm 29.5°C and the Tropical Cyclone Heat Potential--a measure of the total heat content of the ocean--is a very high 100 kJ/cm^2, which is very favorable for rapid intensification. I expect the Tomas will strengthen to a Category 3 or 4 hurricane by Wednesday.


Figure 2. Hurricane specialists Robbie Berg (background) and Dan Brown (foreground) discuss the latest data on Tomas last night at the National Hurricane Center.

Track forecast for Tomas
The computer models have come into better agreement this morning that after Tomas reaches the central Caribbean 4 - 5 days from now, a turn to the north or northeast is likely, in response to a strong trough of low pressure expected to develop over the Eastern U.S. The exact timing of this turn to the north or northeast is difficult to predict at this time, as steering currents will be weak in the Caribbean after Tomas passes through the Lesser Antilles today and Sunday. At this time, is appears that the Dominican Republic and Haiti are most at risk from a strike by Tomas, though the storm could move as far west as Jamaica, or as far east as the northern Lesser Antilles Islands.


Figure 3. Hurricane specialist Dan Brown computes Tomas' radius of tropical storm force winds using the old-fashioned paper track plot and dividers technique. Hurricane specialists at NHC commonly use a paper track plot to mark all storm center fixes and compute the current motion of the storm. A storm's current heading and speed in NHC advisories is usually a 12-hour average of the motion up until the final fix position.

Tomas, Shary, and the 2010 hurricane season in perspective
Tomas' formation ties 2010 with 1995 and 1887 for 3rd place for most number of named storms in an Atlantic hurricane season. Only 2005 (28 named storms) and 1933 (21 named storms) were busier. Atlantic hurricane records go back to 1851, though there were likely many missed named storms prior to the beginning of satellite coverage in the mid-1960s. The intensification of Shary and Tomas into hurricanes today brings the total number of hurricanes this season to twelve, tying 2010 with 1969 and 1887 for second place for most hurricanes in a season. The record is held by 2005 with fifteen hurricanes, and I don't think we'll beat that record this year!

The formation of Tomas so far south and east this late in the season is unprecedented in the historical record; no named storm has ever been present east of the Lesser Antilles (61.5°W) and south of 12°N latitude so late in the year. Hurricane Six of 1896 came close--it was also a tropical storm south of 12°N and east of 61.5°W on October 29, but nine hours earlier in the day. That storm recurved to the north and missed the Lesser Antilles. Tomas' track through the southern Lesser Antilles so late in the year is unprecedented. There have been only two other tropical storms that formed after October 15 south of 12°N and east of 61.5°W: Hurricane Jose, which was a tropical storm in that region on October 18, 1999, and Tropical Storm Nicolas, on October 16, 2003. Tomas most reminds me of a storm I flew into with the Hurricane Hunters--Hurricane Joan of 1988, which was a tropical storm on October 14 near Tomas' current location, and later strengthened into a Category 4 hurricane that hit Nicaragua. According to Chenoweth (2008), Tomas is the first tropical storm to cross through the Lesser Antilles Islands south of 16°N this late in the year since 1724. In that year, a tropical storm on 12 November crossed the islands at 13.7°N 61.5°W, and later became a hurricane that affected Jamaica. There was also a hurricane on 30 October 1671 that crossed 61.5°W at 13.3°N, and did damage on Barbados.

Another unusual aspect of Tomas' formation is that we now have two simultaneous hurricanes in the Atlantic Ocean on October 30. There has been only one hurricane season since 1851 that had had two simultaneous hurricanes later in the year--1932, when Hurricane Ten and Hurricane Eleven both existed November 7 - 10. Today is also the 5th latest date in the season that there have been two simultaneous named storms in the Atlantic. The record was set way back in 1887, when Hurricane Eighteen and Tropical Storm Nineteen were both active on December 8. There were three years that had simultaneous November named storms: 1932, 1961, and 2001.

References
Chenoweth, M. and D. Divine (2008), "A document-based 318-year record of tropical cyclones in the Lesser Antilles, 1690-2007", Geochemistry, Geophysics, Geosystems, 9, doi:10.1029/2008GC002066.

Next update
I'll have more on Sunday by 3pm EDT. I'm headed home to Michigan today, after a very valuable week here at the National Hurricane Center. The experience gave me a new appreciatation for just how good the forecasters are at what they do. NHC's hurricane experts are truly world-class, and we are very fortunate to have such a talented group of hard-working forecasters keeping us informed on the dangers we face from Atlantic hurricanes.

Jeff Masters

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you too bro! going to jam tomorrow evening for business meeting monday and tuesday hope he stays at that slow speed.
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Quoting aspectre:
HurricaneTomas's heading turned to due West
from its previous heading of (8.1degrees west of) WestNorthWest
TS.Tomas's average speed moving between its last 2 reported positions decreasedcreased to ~4.3mph(~7km/h) from its previous travel speed of ~9.3mph(~15km/h)
TS.Thomas
30Oct 12amGMT - 11.6n57.6w - 60mph(~96.6km/h) - . - 999mb - NHC.Adv.#2
30Oct 03amGMT - 12.2n58.4w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3
30Oct 06amGMT - 12.4n58.8w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3A
30Oct 09amGMT - 12.9n59.5w - 70mph(~112.7km/h) - - 994mb - NHC.Adv.#4
30Oct 12pmGMT - 13.1n60.1w - 70mph(~112.7km/h) - - 993mb - NHC.Adv.#4A
30Oct 03pmGMT - 13.3n60.7w - 75mph(~120.7km/h) - - 993mb - NHC.Adv.#5
30Oct 06pmGMT - 13.4n61.0w - 75mph(~120.7km/h) - - 992mb - NHC.Adv.#5A
30Oct 09pmGMT - 13.5n61.4w - 75mph(~120.7km/h) - - 992mb - NHC.Adv.#6
31Oct 12amGMT - 13.5n61.6w - 90mph(~144.9km/h) - - 982mb - NHC.Adv.#7

Copy&paste 11.6n57.6w, 12.2n58.4w, 12.4n58.8w, 12.9n59.5w, 13.1n60.1w-13.3n60.7w, 13.3n60.7w-13.4n61.0w, 13.4n61.0w-13.5n61.4w, 13.5n61.4w-13.5n61.6w, cur, eux into the GreatCircleMapper for a look at the headings and the distances traveled over the last 12^hours.

By the travel speed of 12hours ago, shoulda been past this point 9hours ago. Picked heck of a spot to slow down to organize&strengthen.
I wonder how long is going to stay moving so slow, because the U.S.front is speeding down... good for Jamaica and Cuba bad for Dominican Republic or Puerto Rico...
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Quoting kmanhurricaneman:
aaah ha it sure is stormp

I'm very concerned about Tomas, the one plus is its slow movement, plenty of time to prepare here at least! But one never knows that could change also! Be safe Bro!
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see that what i was saying ealier that TOMASwas gonna slow there by missing that pull north
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Why is the NHC so slow to move Tomas to the N?
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Reports from St. Lucia that the Choc River bridge is failing.
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A Halloween hurricane

Last one was Hurricane Noel in 2007


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aaah ha it sure is stormp
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Tomas is creeping due west , dangerous dude!!!
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Quoting flsky:

OK, but I don't want to hear ANY complaints from until the next election.



my dog will rais Taxs up higher what a good boy
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mmmmmmm.........???????? !!!!!!!
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780. flsky
Quoting Tazmanian:
am voteing for my dog on NOV 2nd

OK, but I don't want to hear ANY complaints from until the next election.
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Tomas maintains its strength.

AL, 21, 2010103100, , BEST, 0, 135N, 617W, 80, 982, HU
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Tomas might be catergory 4 by morning, watch for it!!!
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Sounds like St Lucia is going to have a lot of cleaning up to do, lets hope for no loss of life. I am not so worried about Castries and the North...but Soufriere worries me. I miss the island :(
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774. mbjjm
Quoting clwstmchasr:
I don't know if this has been said today or not but kudos to Levi for predicting Tomas a week ago. He said that the SE Caribbean was primed for development and look what happened. The guy really knows his tropical weather.

There were also many weather blogs especially crown weather which had been warning the Caribbean for the past two weeks.
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Quoting clwstmchasr:
I don't know if this has been said today or not but kudos to Levi for predicting Tomas a week ago. He said that the SE Caribbean was primed for development and look what happened. The guy really knows his tropical weather.


Yeah, Levi's a guy I really respect.
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Hello!

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770. JLPR2


Second tropical cyclone of the south hemisphere 2011 season.
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Quoting Tazmanian:



yes that 90L not being rude but it seen it had it there for some time i evere saw a T # of STS 2.5 at one time i think


Nah you're not being rude. I value your input, as well as a good bit of others here.

We cannot learn if we do not test one another through rigorous, good-spirited debate. Nothing wrong with that, and certainly nothing to regret or apologize for.
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Quoting Bobbyweather:

sorry, I believe you are wrong on the special advisory, which was issued 10pm UTC.



well the new one now is 8pm
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Quoting aspectre:
HurricaneTomas's heading turned to due West

[]ward to (degrees [] of) estNorthWest

from its previous heading of (8.1degrees west of) WestNorthWest
TS.Tomas's average speed moving between its last 2 reported positions decreasedcreased to ~4.3mph(~7km/h) from its previous travel speed of ~9.3mph(~15km/h)
TS.Thomas
30Oct 12amGMT - 11.6n57.6w - 60mph(~96.6km/h) - . - 999mb - NHC.Adv.#2
30Oct 03amGMT - 12.2n58.4w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3
30Oct 06amGMT - 12.4n58.8w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3A
30Oct 09amGMT - 12.9n59.5w - 70mph(~112.7km/h) - - 994mb - NHC.Adv.#4
30Oct 12pmGMT - 13.1n60.1w - 70mph(~112.7km/h) - - 993mb - NHC.Adv.#4A
30Oct 03pmGMT - 13.3n60.7w - 75mph(~120.7km/h) - - 993mb - NHC.Adv.#5
30Oct 06pmGMT - 13.4n61.0w - 75mph(~120.7km/h) - - 992mb - NHC.Adv.#5A
30Oct 09pmGMT - 13.5n61.4w - 75mph(~120.7km/h) - - 992mb - NHC.Adv.#6
31Oct 12amGMT - 13.5n61.6w - 90mph(~144.9km/h) - - 982mb - NHC.Adv.#7

Copy&paste 11.6n57.6w, 12.2n58.4w, 12.4n58.8w, 12.9n59.5w, 13.1n60.1w-13.3n60.7w, 13.3n60.7w-13.4n61.0w, 13.4n61.0w-13.5n61.4w, 13.5n61.4w-13.5n61.6w, cur, eux into the GreatCircleMapper for a look at the headings and the distances traveled over the last 12^hours.

sorry, I believe you are wrong on the special advisory, which was issued 10pm UTC.
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Quoting KoritheMan:


Depends on which 90L you're talking about. If you mean the one we thought would get the name Shary, then it's because convection was never persistent enough. The organization was there, it just never persisted due to strong vertical shear.



yes that 90L not being rude but it seen it had it there for some time i evere saw a T # of STS 2.5 at one time i think
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Quoting Saltydogbwi1:
Link

for anyone interested here is a pic of Deans brush with cayman and a wave shooting over 150 feet into the air I took the pic about half mile from the sea.


Phenomenal. Thanks for sharing.
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Quoting Tazmanian:



no thats it this no???


can you tell me more in why you are saying NO it will not be upgraded


Depends on which 90L you're talking about. If you mean the one we thought would get the name Shary, then it's because convection was never persistent enough. The organization was there, it just never persisted due to strong vertical shear.
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Link

for anyone interested here is a pic of Deans brush with cayman and a wave shooting over 150 feet into the air I took the pic about half mile from the sea.
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HurricaneTomas's heading turned to due West
from its previous heading of (8.1degrees west of) WestNorthWest
H.Tomas's average speed moving between its last 2 reported positions decreased to ~6.7mph(~10.7km/h) from its previous travel speed of ~9.3mph(~15km/h)
TS.Thomas
30Oct 12amGMT - 11.6n57.6w - 60mph(~96.6km/h) - . - 999mb - NHC.Adv.#2
30Oct 03amGMT - 12.2n58.4w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3
30Oct 06amGMT - 12.4n58.8w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3A
30Oct 09amGMT - 12.9n59.5w - 70mph(~112.7km/h) - - 994mb - NHC.Adv.#4
30Oct 12pmGMT - 13.1n60.1w - 70mph(~112.7km/h) - - 993mb - NHC.Adv.#4A
H.Tomas
30Oct 03pmGMT - 13.3n60.7w - 75mph(~120.7km/h) - - 993mb - NHC.Adv.#5
30Oct 06pmGMT - 13.4n61.0w - 75mph(~120.7km/h) - - 992mb - NHC.Adv.#5A
30Oct 09pmGMT - 13.5n61.4w - 75mph(~120.7km/h) - - 992mb - NHC.Adv.#6
31Oct 12amGMT - 13.5n61.7w - 90mph(~144.9km/h) - - 982mb - NHC.Adv.#7A

Copy&paste 11.6n57.6w, 12.2n58.4w, 12.4n58.8w, 12.9n59.5w, 13.1n60.1w-13.3n60.7w, 13.3n60.7w-13.4n61.0w, 13.4n61.0w-13.5n61.4w, 13.5n61.4w-13.5n61.6w, cur, eux into the GreatCircleMapper for a look at the headings and the distances traveled over the last 12^hours.

By the travel speed averaged over the previous day, shoulda been past this point 9hours ago.
Picked heck of a spot to slow down to organize&strengthen.
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Quoting KoritheMan:


No.



no thats it this no???


can you tell me more in why you are saying NO it will not be upgraded
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Quoting kmanhurricaneman:
hello all, back on now after a hectic day, what did i miss??


Tomas is up to 90 mph.
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Quoting Tazmanian:





do you think 90L will be upgraded at seasone ends?


No.
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hello all, back on now after a hectic day, what did i miss??
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757. JLPR2
Tomas seems to be stuck again, its not moving.
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Quoting KoritheMan:


Correct.
Quoting KoritheMan:


Correct.





do you think 90L will be upgraded at seasone ends?
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Quoting cat5hurricane:

Granted, they are not the most ideal conditions, but sufficient enough. That's still under 20 knots. It sure doesn't seem to be affecting him too much as it is based on recent ir sat, radar, and microwave data. He's been under those upper-level conditions for most of the day, and their are expected to lessen with time as that shear (associated with the trough that was near Shary) is retreating.
Well you can see the affects of the shear pretty easily. The system is and has been lopsidded for about a day now. Also there appears to be some sort of minor dry or stable parcel intrusion in the southern quadrant that undermines the convection every once in a while. With shear to remain at 15-20 knots for the next 36 hours, I don't really think that rapid intensification is likely.

Just my opinion though.
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754. JRRP
Member Since: August 16, 2007 Posts: 0 Comments: 5805
the storm is not affecting richard branson on his private islands benifit party with the victoria secret girls
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752. SLU
Quoting MiamiHurricanes09:
Based on damage reports, it sounds to me like Tomas is nearing major hurricane strength.


It looks like everyone, including the NHC has totally underestimated the power of this tropical cyclone.

Quoting KoritheMan:


Yikes... Hope it doesn't turn out as bad as that.


Everyone I talk to says that it's really bad.
Member Since: July 13, 2006 Posts: 12 Comments: 5136
Quoting Stormchaser2007:

Where are these damage reports from?

I've only heard of some roof damage and minor structural damage in St. Lucia
Radio stations, news, etc. Here's a CNN iReport showing some pictures taken on the island of Barbados:

a href="http://ireport.cnn.com/docs/DOC-510680?ref=feeds%2Foncnn" target="_blank"CNN iReport

I've also been reading the reports on here, and even though they may not be accurate, they give you a perspective of what's going on.
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750. JRRP
Member Since: August 16, 2007 Posts: 0 Comments: 5805
Quoting SLU:
Just got a call from my brother in St. Lucia and he told me that the rainfall is absolutely torrential accompanied by very strong winds and that there were no lights visible on the island. All the radio stations and television stations have been knocked off air. He sounded very, very concerned about the severity of the hurricane and that he believes the island could be completely devastated. Like nothing we've seen on St. Lucian soil since the passage of Major Hurricane Allen in 1980.



What can anyone say, it is devastating in more ways than one, I remember every minute of Ivan. Our thoughts are with all on all the Islands that were hit.
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Quoting Tazmanian:




from a 40 TS too a 90 mph hurricane in less then 24hrs? thats a RI


Correct.
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Quoting Stormchaser2007:
The conditions aren't really there for this to really take off.

Maybe just steady intensification for now.






from a 40 TS too a 90 mph hurricane in less then 24hrs? thats a RI
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Hatian missionaries are coming home tomorrow...I don't know if it's too early to make that call or not...I wonder when Sanjay Gupta will leave? I hope they are spared.
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Quoting SLU:
Just got a call from my brother in St. Lucia and he told me that the rainfall is absolutely torrential accompanied by very strong winds and that there were no lights visible on the island. All the radio stations and television stations have been knocked off air. He sounded very, very concerned about the severity of the hurricane and that he believes the island could be completely devastated. Like nothing we've seen on St. Lucian soil since the passage of Major Hurricane Allen in 1980.


Yikes... Hope it doesn't turn out as bad as that.
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Quoting MiamiHurricanes09:
Based on damage reports, it sounds to me like Tomas is nearing major hurricane strength.
Where are these damage reports from?

I've only heard of some roof damage and minor structural damage in St. Lucia
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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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