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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any one think will make it too the W storm
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Good Night All. Grenada, what were the effects of Tomas up there. In Trinidad we had hot sun, not a drop of rain.
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Good Night All. Grenada what were the effects of Tomas up there...Here in Trinidad was hot sun...not a drop of rain.
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splitted in two storms? it appears to be.

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Quoting Tazmanian:
am voteing for my dog on NOV 2nd


Taz,..your so funny.....just as long as you DO vote :)
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638. amd
eye even beginning to appear on satellite. Latest imagery from Ramsdis:

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Quoting MarcoIslandCat5:
wow tomas is moving alot more west than i expected just hope he hooks ne before 80w/85w my 16 yo son is on his first vacation abroad in the caymans... what a crazy huricane season this is turning into,
hears the live radio link from st lucia the pm is about to adress the nation..
You do not need to be overly worried about him. The building codes are higher than Florida's and flooding is not a big issue. I cannot say I do not fear hurricanes because since Ivan I do but thank God we only had two deaths and both could have been prevented. One man decided to ride it out on his boat and another man went outside to see what was going on and flying debris hit him in his chest. Had a few afterwards from improper use of generators.
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impressive video coming from barbados
Member Since: September 11, 2010 Posts: 1 Comments: 4332
Quoting Grenada:



I think he/she was probably a bit frightened and thought if he stayed still I wouldn't see it. I took a couple of other shots too one you could see bits of white stuff all over his body as if he was a really new baby.


Not an expert but we have MANY of those here the white pieces you saw was probably dead skin and the iguana was shedding.
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Call me paranoid but I bought my plywood today and did the supermarket.
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wow tomas is moving alot more west than i expected just hope he hooks ne before 80w/85w my 16 yo son is on his first vacation abroad in the caymans... what a crazy huricane season this is turning into,
hears the live radio link from st lucia the pm is about to adress the nation.. http://www.ustream.tv/channel/hurricanecity-stream
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Quoting Grenada:



I think he/she was probably a bit frightened and thought if he stayed still I wouldn't see it. I took a couple of other shots too one you could see bits of white stuff all over his body as if he was a really new baby.
I like them and have one for a pet. They can grow big and are easily tamed.
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Quoting islandblow:
Hewanorra International Airport Terminal in south St. Lucia has lost its roof and further damage there is being reported.
Which island are you on again ?
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It's definately not summer in SW Florida. It's nice a warm, but the humidity is very low.

86 °F
Mostly Cloudy
Humidity: 35% Dew Point: 55 °F
Wind: 5 mph from the North

Pressure: 30.01 in (Steady)
Heat Index: 84 °F
Visibility: 10.0 miles
UV: 0 out of 16
Pollen: 3.70 out of 12
Pollen Forecast new!
Clouds: Mostly Cloudy 7000 ft
(Above Ground Level)
Elevation: 30 ft
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I think a lot of Europe falls back this weekend. It makes meetings next week a guessing game for us at work....
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Quoting stormwatcherCI:
Off topic but how did you manage to get so close to that iguana for such a close-up picture ?



I think he/she was probably a bit frightened and thought if he stayed still I wouldn't see it. I took a couple of other shots too one you could see bits of white stuff all over his body as if he was a really new baby.
Member Since: August 21, 2010 Posts: 0 Comments: 96
Hewanorra International Airport Terminal in south St. Lucia has lost its roof and further damage there is being reported.
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Quoting goldmind:
thanks grenada
Im sorry tazz about the yelling i forgot to press the caps lock key



ok
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thanks grenada
Im sorry tazz about the yelling i forgot to press the caps lock key
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Quoting Grenada:
:)
Off topic but how did you manage to get so close to that iguana for such a close-up picture ?
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Quoting CybrTeddy:
Quite a significant pressure drop too in an hour.
SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.5N 61.4W
ABOUT 35 MI...55 KM SW OF ST. LUCIA
ABOUT 20 MI...30 KM NW OF ST. VINCENT
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/HR
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 10 MPH...17 KM/HR
MINIMUM CENTRAL PRESSURE...992 MB...29.29 INCHES



SUMMARY OF 600 PM AST...2200 UTC...INFORMATION
----------------------------------------------
LOCATION...13.5N 61.6W
ABOUT 45 MI...75 KM WSW OF ST. LUCIA
ABOUT 30 MI...50 KM WNW OF ST. VINCENT
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/HR
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 10 MPH...17 KM/HR
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES
Teddy, if he continues to intensify at the rate he is going what effect would the ridge and the trough have on his track ?
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:)
Member Since: August 21, 2010 Posts: 0 Comments: 96
Quoting Tazmanian:




no its not daylight saveing times at all any where not in tell nov 7th now plzs stop yelling

it is in Great britain :)
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Quoting Grenada:



The UK fall back an hour on 31st October.





now you tell me
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Quoting Tazmanian:




no its not daylight saveing times at all any where not in tell nov 7th now plzs stop yelling



The UK fall back an hour on 31st October.

Member Since: August 21, 2010 Posts: 0 Comments: 96
dos any one think 90L stans a ch of being upgraded at post seasone
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pretty much everyone knows john hopes rule but only the old timers know the second line " if its developed it can bomb out just past the windwards"
Member Since: September 11, 2010 Posts: 1 Comments: 4332
Didn't anyone else find it odd that every storm so far this month has reached hurricane strength? I just noticed it.
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Quoting goldmind:
SORRY TAZZ, YOUR RIGHT. LET ME REFRASE:
IN SOME COUNTRIES OF THE NORTHERN HEMISFERE DON'T FORGET, THE DAYLIGHT SAVING TIME ENDS TONIGHT




no its not daylight saveing times at all any where not in tell nov 7th now plzs stop yelling
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Quoting Stormchaser2007:



i think an eye is ready to pop out of all that
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Tomas defiantly looking stronger
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Quoting Stormchaser2007:

Hurricane Omar




I mean a westward traveling hurricane from the Central Atlantic like Dean, Felix, Emily, ect.
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who thinks this could go north and pull a hazel track to the carolinas?
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607. mbjjm
Live radio from St. Vincient







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SORRY TAZZ, YOUR RIGHT. LET ME REFRASE:
IN SOME COUNTRIES OF THE NORTHERN HEMISFERE DON'T FORGET, THE DAYLIGHT SAVING TIME ENDS TONIGHT
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10MB pressure drop in an hour shows that the eye is forming and/or is about to show up on the sat's.
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Quoting stormpetrol:
A very serious situation is developing in the Caribbean, hope everyone is prepared and ready! Please be safe!!


it could go any were now
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Quoting CybrTeddy:


Nah, totally different conditions than Dean.

Although, we haven't seen a hurricane in the Eastern Caribbean since Dean and Felix.
Hurricane Omar


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Quite a significant pressure drop too in an hour.
SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.5N 61.4W
ABOUT 35 MI...55 KM SW OF ST. LUCIA
ABOUT 20 MI...30 KM NW OF ST. VINCENT
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/HR
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 10 MPH...17 KM/HR
MINIMUM CENTRAL PRESSURE...992 MB...29.29 INCHES



SUMMARY OF 600 PM AST...2200 UTC...INFORMATION
----------------------------------------------
LOCATION...13.5N 61.6W
ABOUT 45 MI...75 KM WSW OF ST. LUCIA
ABOUT 30 MI...50 KM WNW OF ST. VINCENT
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/HR
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 10 MPH...17 KM/HR
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES
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Quoting Dakster:
I am having blog freeze... But basically if Tomas becomes a major or is a major next week that could break an official record for the latest forming (or occuring) Cat 5?


A major and a CAT 5 are not the same thing
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600. MZT
There are some flecks of white in the rainbow image... that is very rare. There must be some intense towers in that thing. Some *light green* in the JSL image too. Not just the dark green, which is impressive enough...
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I am having blog freeze... But basically if Tomas becomes a major or is a major next week that could break an official record for the latest forming (or occuring) Cat 5?
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Quoting hurricanehunter27:
This could be dean part 2. =(


Nah, totally different conditions than Dean.

Although, we haven't seen a hurricane in the Eastern Caribbean since Dean and Felix.
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Quoting goldmind:
DON'T FORGET, THE DAYLIGHT SAVING TIME ENDS TONIGHT



hmmmm no it dos not it end NOV 7th i looked this AM
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Quoting goldmind:
DON'T FORGET, THE DAYLIGHT SAVING TIME ENDS TONIGHT
For Who???
Member Since: June 13, 2009 Posts: 0 Comments: 6732
Quoting goldmind:
DON'T FORGET, THE DAYLIGHT SAVING TIME ENDS TONIGHT


Got another week!
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Welcome to the world of climate change kids.
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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.