Tomas gradually strengthening; 14 dead in St. Lucia from the storm

By: Dr. Jeff Masters , 2:58 PM GMT on November 02, 2010

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The islands of St. Lucia, Barbados, and St. Vincent and the Grenadines continue to assess damage and clean up after Hurricane Tomas pounded the Lesser Antilles as a strengthening Category 1 hurricane with 90 - 95 mph winds on Saturday. St. Lucia was hardest hit, with fourteen people dead, many more missing, and damage estimated at $100 million--about 10% of the nation's GDP. Damage on neighboring St. Vincent was estimated at $62 million, which is 4% of that nation's GDP. The storm damaged 1,200 houses, and the northern half of the island, where most of the crops are, was badly hit, with no banana trees left standing and the plantain crop wiped out. Banana production employs 60% of the workforce on St. Vincent, and accounts for more than 50% of their exports. Also hard-hit was Barbados, where damage estimates are at $55 million, 1.5% of the nation's GDP. Tomas may be the most damaging storm to affect the island since Hurricane Janet of 1955. The havoc wreaked by Tomas in the Lesser Antilles makes is likely that the name Tomas will be retired from the list of active hurricane names in the Atlantic.


Figure 1. Torrential rains from Tomas triggered massive flooding on St. Lucia that destroyed several bridges and severely damaged roads. Image credit: St. Lucia Star.

Tomas gradually strengthening
Satellite loops of Tomas show a considerably more organized storm than yesterday, with a modest but increasing amount of heavy thunderstorm activity. However, low-level spiral bands are limited, and upper-level outflow is weak, and Tomas is not in danger of building an eyewall today. Curacao radar shows that the echoes from Tomas are disorganized, with no spiral banding apparent. Wind shear has declined to a moderate 10 -15 knots and the atmosphere in the Caribbean has moistened over the past day, allowing Tomas to re-organize. A hurricane hunter aircraft is on its way to Tomas this morning, and will have a better estimate of the storm's strength by early this afternoon.


Figure 2. Curacao radar at 10:07am EDT on Tuesday, November 2, 2010, showed a large area of rain associated with Tomas over the central Caribbean, but these echoes were poorly organized.

Track forecast for Tomas
The ridge of high pressure pushing Tomas to the west has weakened, allowing Tomas to slow down slightly to a forward speed of 10 mph this morning. This speed will decrease further to 5 mph tonight, as a trough of low pressure approaches the eastern U.S. and breaks down the ridge. By Wednesday, the trough to Tomas' north should be able to pull the storm to the northwest. Tomas' outer spiral bands will bring heavy rains to southwestern Haiti and eastern Jamaica beginning on Thursday night. The computer models have come into better agreement that Tomas will turn more to the north-northeast by Friday, with Haiti or Jamaica the most likely landfall locations. NHC is giving Port-au-Prince, Haiti, a 50% chance of receiving tropical storm force winds, and a 6% chance of hurricane force winds. These odds are 45% and 7%, respectively for Kingston, Jamaica, and 23% and 3% for Santo Domingo in the Dominican Republic.

Tomas may stall
The models are increasingly suggesting the once Tomas begins moving to the north-northeast, the trough pulling the storm that direction will lift out, stranding Tomas in a region of weak steering currents. Tomas may then wander and dump heavy rains for several days, Saturday through Monday. Given recent model trends, I believe this is likely, but the exact location where Tomas might be stranded is uncertain. The NOGAPS model gives a nightmare scenario for Haiti, with Tomas remaining stationary just off the coast from Port-Au-Prince as a hurricane for many days. The UKMET stalls Tomas over the Turk and Caicos Islands, while the GFS, GFDL, and ECMWF models predict Tomas will stall several hundred miles north of Hispaniola and drift eastwards. It's reasonable to go with the model consensus and predict Tomas will pass over western Haiti and stall far enough north of the nation so that heavy rains will not linger over Hispaniola for many days. The uncertainties in the track forecast are greater than usual, though.

Intensity forecast for Tomas
Wind shear as diagnosed by the SHIPS model has dropped to the moderate range, 10 - 15 knots, and is predicted to stay low to moderate, 5 - 15 knots, for the remainder of the week. The relaxation of shear should allow Tomas to continue to re-organize over the next few days. Aiding this process will be an increasingly moist atmosphere. Dry air has decreased significantly over the past 24 hours, as seen on water vapor satellite imagery, and the models predict a very moist atmosphere will surround Tomas for the remainder of the week. With SSTs at a record warm 29.5°C and a very high ocean heat content, there is a substantial danger that Tomas will undergo a period of rapid intensification once it rebuilds its inner core and establishes an eyewall. This is not likely to happen today, but could occur as early as Wednesday night. This may give Tomas sufficient time to intensify into a major hurricane before landfall in Haiti or Jamaica, as predicted by the GFDL model. The most reasonable intensity forecast at this point is to call for a landfall on Friday at Category 2 strength, but Tomas could easily be anywhere from Category 1 to Category 3 hurricane strength on Friday. NHC is giving Tomas a 19% chance of reaching Category 3+ strength; I believe these odds are higher, 40%. With the atmosphere expected to be very moist, it is likely that Tomas will dump very heavy rains of 4 - 8 inches over much of Haiti, even if Tomas strikes as a tropical storm. Rains of this magnitude are capable of causing heavy loss of life due to extreme floods running down Haiti's deforested mountain slopes. Portlight.org is preparing to send their mobile kitchen with enough food to feed 500 people per day, if Tomas continues on its current forecast path.


Figure 3. Plot of all Category 1 and stronger hurricanes to pass within 50 miles of Barbados since reliable record keeping began in 1851. Image credit: NOAA Coastal Services Center.

Barbados hurricane history
Tomas is the strongest hurricane to affect Barbados since Category 3 Hurricane Allen of 1980, which passed just north of the island. Allen did $4 million in damage, compared to Tomas' $55 million. The deadliest hurricane in Barbados history was the Category 5 Great Hurricane of 1780, which killed approximately 4500 people on the island, and leveled every building, including the stone governor's mansion. The Great Hurricane of 1780 was also the Atlantic's deadliest hurricane of all-time, with 22,000 fatalities, mostly in the Lesser Antilles Islands.

Next update
I'll have an update Wednesday morning.

Jeff Masters

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858. Skyepony (Mod)
Looks like they've about Xed that one spot, 2nd time even less pretty & there is another wind shift to the NE of there. A bit a mess overall but rolling away from South America which has been impeding Tomas pretty good. Structure looks improved, convection beginning to rapidly build from just south of center & still hours to D-max.. I'm guessing we might not get a Vortex message from this flight.

JRRP~ HAha..well only cause the NOGAPS has been lost as to where Tomas will go so far..
Member Since: August 10, 2005 Posts: 174 Comments: 38172
would it be possible for the western half to split off and become a separate storm?
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856. JLPR2
Quoting JRRP:
jajajajaaja LOLASO
Link


LOL! Seriously? That's nuts!
Member Since: September 4, 2007 Posts: 7 Comments: 8733
855. JRRP
jajajajaaja LOLASO
Link
Member Since: August 16, 2007 Posts: 0 Comments: 5974
000
WTNT31 KNHC 030544
TCPAT1
BULLETIN
TROPICAL STORM TOMAS INTERMEDIATE ADVISORY NUMBER 20A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010
200 AM EDT WED NOV 03 2010

...TOMAS BARELY A TROPICAL STORM...BUT EXPECTED TO RESTRENGTHEN...


SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...13.2N 75.2W
ABOUT 415 MI...670 KM SSW OF PORT-AU-PRINCE HAITI
ABOUT 350 MI...560 KM SSE OF KINGSTON JAMAICA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/HR
PRESENT MOVEMENT...WSW OR 250 DEGREES AT 6 MPH...9 KM/HR
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WATCH IS IN EFFECT FOR...
* JAMAICA

INTERESTS IN HAITI...THE DOMINICAN REPUBLIC...AND SOUTHEASTERN CUBA
SHOULD ALSO MONITOR THE PROGRESS OF TOMAS. TOMAS COULD POSE A
SIGNIFICANT THREAT TO THOSE AREAS LATER IN THE WEEK.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 AM EDT...0600 UTC...THE CENTER OF TROPICAL STORM TOMAS WAS
LOCATED NEAR LATITUDE 13.2 NORTH...LONGITUDE 75.2 WEST. TOMAS HAS
BEEN MOVING TOWARD THE WEST-SOUTHWEST NEAR 6 MPH...9 KM/HR. A TURN
TOWARD THE WEST-NORTHWEST...NORTHWEST...AND NORTH IS EXPECTED
DURING THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS ARE ESTIMATED TO BE NEAR 40 MPH...65
KM/HR...WITH HIGHER GUSTS. REPORTS FROM AN AIR FORCE HURRICANE
HUNTER PLANE INDICATE THAT TOMAS MAY BE WEAKENING TO A TROPICAL
DEPRESSION
. HOWEVER...THE SYSTEM IS EXPECTED TO BEGIN
RESTRENGTHENING LATER TODAY OR TONIGHT.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 105 MILES...165 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB...29.71 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 AM EDT.

$$
FORECASTER PASCH/ROBERTS
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how could a vorticity map be created with no instruments around to measure?
just a guess?
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Nada.. I am off to bed.. its getting late for someone my age.




Member Since: October 1, 2007 Posts: 81 Comments: 26511
The only thing not looking good is that S shape that it acquired..... We'll se tomorow.... Gnite All

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>thanks for explaining this seemingly complex wind event
not as easy to understand as i thought
very 3-d with many components
too many new questions for my typing ability
ill be studying this hard for sure
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Quoting medicroc:

Trying to keep the faith but my old lady is in DR and tells me torrential rain has already been falling for the last 12 hours.


Too bad.... Seems like here in PR, we will get quite a lot, as everything moves NE....
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What a huge amount of WV in the Carib & Atl....

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Quoting sunlinepr:


Let's keep the Faith, seems like projected center path is now out to the W, between Haiti and Cuba.... And its still at 45mph.... At least 12 more hours that it keeps moving W... the best would be that it to disipate....


Trying to keep the faith but my old lady is in DR and tells me torrential rain has already been falling for the last 12 hours.
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846. Skyepony (Mod)
PORT-AU-PRINCE, Haiti (AP) — It was the jewel of Haiti's post-earthquake recovery: an organized relocation camp with thousands of tents billed as hurricane-resistant, lined up in neat rows on graded mountain soil.

Now, staring down an expected hit later this week from a hurricane, officials say Corail-Cesselesse is not safe. On Tuesday, the government advised the estimated 7,850 residents of its primary relocation camp to ride out the storm somewhere else.

"We're asking people in Corail to voluntarily move from where they are and go to the houses of family or friends. The places the government has identified are churches and schools that are available for shelter from the storm," Haiti civil protection official Abel Nazaire told The Associated Press.

Camp managers held a "loudspeaker meeting" with megaphones to tell residents about the evacuation order, said Bryant Castro, the American Refugee Committee staffer managing the camp. Residents were told to seek any home they could find and are expected to start leaving as soon as Wednesday.

more
Member Since: August 10, 2005 Posts: 174 Comments: 38172
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Quoting medicroc:

Cholera outbreak will be impossible to contain after this


Let's keep the Faith, seems like projected center path is now out to the W, between Haiti and Cuba.... And its still at 45mph.... At least 12 more hours that it keeps moving W... the best would be that it to disipate....

Member Since: Posts: Comments:
Quoting causesandconditions:
so sheer would go the same direction as the incoming front?
Please forgive my lack of understanding


No. Shear would be southwesterly (blowing from the southwest) in advance of an approaching front, then veer to northwesterly behind it.
Member Since: Posts: Comments:
840. Skyepony (Mod)
Quoting uncljbnd:
They are not calling that the center are they?


Have to wait on a vortex message to answer that. Cernainly had a switch of winds & a drop off in the middle with some sort of lower pressure around. Last run they called the exact spot by the temp rise.. Looks a little like tropical trash so far.
Member Since: August 10, 2005 Posts: 174 Comments: 38172
Quoting sunlinepr:


Catastrophic, worst than the earthquake.... HOPE NOT....
Quoting sunlinepr:


Catastrophic, worst than the earthquake.... HOPE NOT....

Cholera outbreak will be impossible to contain after this
Member Since: Posts: Comments:
They are not calling that the center are they?
Member Since: July 22, 2010 Posts: 0 Comments: 67
Quoting causesandconditions:
so sheer would go the same direction as the incoming front?
Please forgive my lack of understanding


Here you can find info about Wind Shear.... Wikipedia is a good fast resource...

Link
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836. Skyepony (Mod)
That fix looked very broad..~13.183N 75.067W
Member Since: August 10, 2005 Posts: 174 Comments: 38172
Nothing below 1007 so far



Member Since: October 1, 2007 Posts: 81 Comments: 26511
834. Skyepony (Mod)
Recon looks to feeling less threatened tonight, down to 2500'..
Member Since: August 10, 2005 Posts: 174 Comments: 38172
833. Skyepony (Mod)
Storms are steered according to strength... the stronger & taller they are the higher in the atmosphere you'd look at the steering currents. Kinda neat how CIMSS has added the TC storm strength next to each layer selection recently to better pick the steering layer to look at for each storm.. Using Tomas~ at intensity of last HH, if he didn't restrengthen, then westward to (no surprise)~Belize.. But it's dynamic & changing that tells you only the now. The Low over TX in moving & shear is expected to drop & well these things strengthen when they feel a front.. all that pressure gradient.. so bump it up to one stronger & take a gander & again..

Sheer is the difference in direction & speed the different layers move. Over 20kts can be pretty detrimental to about all but the most determined storms. Sometimes weaker storms can survive in higher shear if the worst of the shear is high up where the storm hasn't built to. Tomas would do best to get back coupled with that anticyclone.. the area nearby with the orange lines spinning away from the 5kt shear center in a clockwise motion.. That's an upper high, the perfect vent & shear blocker for a low level low to explode.
Member Since: August 10, 2005 Posts: 174 Comments: 38172
thanks bordonaro----u da man
i will study this
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Quoting Orcasystems:


I gave it to ice cream about an hour ago.. I think he is answering it


ok just email me if he doesnt know :)
Member Since: September 6, 2007 Posts: 0 Comments: 6598
you all are in for it now
might as well start answering my
questions now
save yourself the trouble later
thanks
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Quoting VAbeachhurricanes:


I got you Orca, if you question has not yet been answered I can.


I gave it to ice cream about an hour ago.. I think he is answering it
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting causesandconditions:
so sheer would go the same direction as the incoming front?
Please forgive my lack of understanding

No a different direction
Link
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Quoting Orcasystems:
Who is a political wizz kid I can WU a question to?


I got you Orca, if you question has not yet been answered I can.
Member Since: September 6, 2007 Posts: 0 Comments: 6598
Station 42056
NDBC
Location: 19.874N 85.059W
Conditions as of:
Wed, 3 Nov 2010 03:50:00 UTC

Winds: E (80°) at 7.8 kt gusting to 9.7 kt
Significant Wave Height: 3.9 ft
Dominant Wave Period: 13 sec
Mean Wave Direction: E (94°)
Atmospheric Pressure: 29.90 in and rising
Air Temperature: 81.3 F
Dew Point: 75.0 F
Water Temperature: 83.8 F
Link
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so sheer would go the same direction as the incoming front?
Please forgive my lack of understanding
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Quoting tornadodude:


oh write on!

thanks (:

:o)
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Quoting Bordonaro:

Click on the "write for us" tab and submit a writing sample :o)


oh write on!

thanks (:
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting tornadodude:


thats awesome!

how does one get involved in that?

Click on the "write for us" tab and submit a writing sample :o)
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Quoting Bordonaro:

Making a little extra cash doing what I love..
The newest on spotlights Portlight in Haiti/Tomas preparation:
Link


thats awesome!

how does one get involved in that?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting sunlinepr:


Catastrophic, worst than the earthquake.... HOPE NOT....

The way Tomas looks maybe it will do everyone a favor and dissipate!!
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http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_4km_ir4_floater_1



poof...no paint needed
Member Since: July 22, 2010 Posts: 0 Comments: 67
Quoting causesandconditions:
thanks for the answer---
usualy called vert shear, what point and why does it turn horizontal ?

Converging air, like ahead of a cold front or an upper level low.
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Quoting tornadodude:


Hey,

how you been?

I've been keeping up with your weather articles, some good stuff!

Making a little extra cash doing what I love..
The newest on spotlights Portlight in Haiti/Tomas preparation:
Link
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Quoting docrod:


ok ok lol

Navy blue; Royal blue; Powder blue !!

which ...




Pick one I guess... I didn't say it

752. uncljbnd 3:09 AM GMT on November 03, 2010 Hide this comment.
I am no meteorologist but if the HH find a tropical storm I will paint my butt blue
Member Since: October 1, 2007 Posts: 81 Comments: 26511
thanks for the answer---
usualy called vert shear, what point and why does it turn horizontal ?
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Quoting KEEPEROFTHEGATE:
i don't know TD in a thunder storm you have great hazards winds hail lightening strikes all fatal to an i pod


You have to build a housing that can withstand those eventualities....
In The ballon proyect they did build a cover for the iphone that went 100,000 ft. up and ended up in a tree more than 60 miles from launch.... One solution is to use a cheap 5-7 mpixel camera.... that has video. Even met. weather ballons have sensitive electronics that are sent into storms and do their job...
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Quoting Bordonaro:

Steering currents are normally at 35,000 feet..Wind shear is the changing with height, normally at 12-18,000 feet


Hey,

how you been?

I've been keeping up with your weather articles, some good stuff!
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting causesandconditions:
new guy on block
long time lurker
KOG,ORCA,anyone
ref:post783
diff between steering current+
sheer direction please
show the love
thanks

Steering currents are normally at 35,000 feet..Wind shear is the changing with height, normally at 12-18,000 feet
Member Since: Posts: Comments:
new guy on block
long time lurker
KOG,ORCA,anyone
ref:post783
diff between steering current+
sheer direction please
show the love
thanks
Member Since: Posts: Comments:
How long does it take for the HH to complete a run?
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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.