Strengthening Tomas headed for the Lesser Antilles

By: Dr. Jeff Masters , 1:27 AM GMT on October 30, 2010

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Tropical Storm Tomas has exploded into existence in spectacular fashion, becoming the nineteenth named storm of this amazingly active 2010 Atlantic hurricane season. I'm reporting to you live from the National Hurricane Center tonight, where forecasters are working hard to stay abreast of Tomas' intensification. Three hurricane specialists are on duty tonight--Dave Roberts, who is handling Tropical Storm Shary, and Robbie Berg and Dan Brown, who are focusing on Tomas. The Hurricane Hunters have just left Tomas, as of 8pm EDT, and they found a significant increase in winds. Winds at their 1500 foot flight level were 70 mph, and surface winds as measured by the SFMR instrument were near 60 mph. This supports an increase in Tomas' winds to 60 mph in tonight's 8pm EDT public advisory. Since this is such a large increase in intensity from what was forecast--Tomas was not supposed to have 60 mph winds for another 24 hours--this necessitates issuance of a special advisory package. A full set of forecast maps, a marine advisory, wind probability forecast, and a discussion just went out to the world. While all this was occurring, several phone calls to Barbados, St. Lucia, and Martinique were made, alerting the islands to the fact that a Hurricane Warning may be required with the 11pm advisory tonight. NHC has both French speaking and Spanish speaking meteorologists on staff that can coordinate with the islands that don't have English as their main language. I listened in on a 5-minute conversation in French between the weather service in Martinique and NHC meteorologist Mike Tichacek, as they discussed when Martinique may want to issue a Hurricane Warning.


Figure 1. Warren VonWerne (right) of CARCAH presents the latest data from the Air Force Hurricane Hunters to hurricane specialist Robbie Berg.

Intensity forecast for Tomas
The forecasters at NHC are puzzling over the latest intensity forecasts for Tomas. The latest intensity forecast from the GFDL, HWRF, and SHIPS models are not that impressive, and they keep Tomas as a strong tropical storm or weak hurricane for the next five days. The wind shear forecast from SHIPS is particularly odd--the latest 18Z forecast predicts high wind shear of 20+ knots beginning Sunday morning, and the previous SHIPS forecast held wind shear below 15 knots for the next five days. The latest runs by the GFS, ECMWF, and UKMET models all show a very favorable environment for intensification over the next five days over the Caribbean, with Tomas positioning itself beneath an upper level high in a light wind shear environment. The best bet is that Tomas will intensify into a major hurricane over the Central Caribbean by early next week.


Figure 2. NHC meteorologist Mike Tichacek discusses the latest intensity forecast for Tomas with the Martinique weather service (in French.) In the background, hurricane specialist Dave Roberts works on advisories for Tropical Storm Shary.

Track forecast for Tomas
After Tomas reaches the central Caribbean 4 - 6 days from now, there are two possible track scenarios depicted by the models--a continued westerly motion towards Nicaragua, or a sharp turn to the north, with a track over Hispaniola or Puerto Rico. Steering currents will be weak, and we'll just have to wait and see how the steering currents evolve.

Tomas' formation location unprecedented this late in the season
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 formation of a tropical storm 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 (60°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 60°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 60°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 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.

Another unusual aspect of Tomas' formation is that we now have two simultaneous named storms in the Atlantic Ocean on October 29. There have been only four hurricane seasons since 1851 that have had two simultaneous named storms later in the year. 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.

Next update
I'll have more late Saturday morning.

Jeff Masters

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Haven't updated this one in a while, but as it seems we may have some literal-minded visual types on here tonight:

Appropriate tropical weather-related image

;-)
Member Since: November 8, 2009 Posts: 4 Comments: 13549
Quoting JLPR2:
1- 2005 Atlantic hurricane season 28 15 7
2- 1995 Atlantic hurricane season 19 11 5
2- 2010 Atlantic hurricane season 19 10 5
3- 1969 Atlantic hurricane season 18 12 5

Rather impressive, 2010 is tied with 1995 for the second place for the most named storms during a Atl. Hurricane Season.
we still got all of nov and very early dec left in 25 mins we got 31 days to go
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Quoting JLPR2:
1- 2005 Atlantic hurricane season 28 15 7
2- 1995 Atlantic hurricane season 19 11 5
2- 2010 Atlantic hurricane season 19 10 5
3- 1969 Atlantic hurricane season 18 12 5

Rather impressive, 2010 is tied with 1995 for the second place for the most named storms during a Atl. Hurricane Season.


You're forgetting 1933 ;) 21 storms formed during that season
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just 27 more posts to get to a new page that is NORMAL SIZE!!!..ahhhhhhhhhhhhhhhhhhhh
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What I've seen so far, is a system that is moving more N than the supposed WNW... Even the forecasted points are SW of where the COC is....
Even local news, like Wapa and Univision are presenting old model diagnostics....

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273. JLPR2
1- 2005 Atlantic hurricane season 28 15 7
2- 1995 Atlantic hurricane season 19 11 5
2- 2010 Atlantic hurricane season 19 10 5
3- 1969 Atlantic hurricane season 18 12 5

Rather impressive, 2010 is tied with 1995 for the second place for the most named storms during a Atl. Hurricane Season.
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Quoting Grothar:


Behave!!

Thanks.
Dont know why he is so squeemish.
They work really well.
Had them hung all around my property all week..
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Quoting Rainwalker:
It is the first time I have ever seen so many people in Jamaica making so much noise over a stom.

I thought I was the only one in Jamaica who heard about it because I haven't heard anyone say anything.
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Quoting Grothar:


Behave!!


Me... behave.. but Mom he started it???
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting KEEPEROFTHEGATE:
the second and with it winter


I took one look at Thomas this morning.. and booked the vacation to Puerto Valarta this afternoon,Jan 7-21 :)

Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting PSLFLCaneVet:


On the right hand side of this page is a section entitled: Recommended Links. Click on "Flying into Hurricane Hugo". You'll be ready to go. And a warm welcome to you!


Thanks..and Pottery as well.
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Nice sat pic of Megi...
Member Since: September 27, 2007 Posts: 1 Comments: 21407
Quoting Orcasystems:



ewwwwww


Behave!!
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It is the first time I have ever seen so many people in Jamaica making so much noise over a storm.
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Quoting aspectre:
TropicalStormTomas's heading turned westward to (7.6degrees west of) NorthWest
from its previous heading of (11.2degrees west of) dueNorth
TS.Tomas's average speed moving between its last 2 reported positions increasedcreased to ~22.7mph(~36.5km/h) from its previous travel speed of ~11.7mph(~18.8km/h)
Invest91L
29Oct 12amGMT - - 8.5n52.0w - 30knots(~55.6km/h) - 1006mb - ATCF
29Oct 06amGMT - - 9.3n53.7w - 30knots(~55.6km/h) - 1006mb - ATCF
TropicalDepression21
29Oct 12pmGMT - 10.0n55.3w - 30knots(~55.6km/h) - 1003mb - ATCF
TS.Thomas
29Oct 06pmGMT - 10.8n56.8w - 35knots(~64.8km/h) - - 998mb - ATCF
29Oct 09pmGMT - 11.1n57.5w - 40mph(~64.4km/h) - . - 998mb - NHC.Adv.#1
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

Copy&paste 8.5n52.0w, 9.3n53.7w, 10.0n55.3w-10.8n56.8w, 10.8n56.8w-11.1n57.5w, 11.1n57.5w-11.6n57.6w, 11.6n57.6w-12.2n58.4w, pmv, uvf, 12.2n58.4w-13.044n59.527w into the GreatCircleMapper for a look at the headings and the distances traveled over the last 18^hours.

Using straightline projection upon the speed&heading averaged
over the 3hours spanning the last two reported positions:
~4hours from now to GreenGardens,Barbados

^ The westernmost line-segment is the straightline projection.
Each of the 3 preceding line-segment spans 3hours between positions.
The easternmost line-segment spans 6hours between positions.

That's a few degrees north of what I was expecting.
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Imbedded in the westerlies, again, very rare to have a big system so far south, let alone the time of year. Even in early summer it's tough to spin one up down where Tomas is right now. This one is a rare event, so the forecasters are going to find it tough to predict the north turn.
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there is no big cold front forecast to move through KS OK, TX on Wednesday or Thursday.

I like the West and Southerly solution with no recurvature solution based upon the Mid Continent forecasts.

This "trough" everyone is discussing is a nothing burger, IMO.




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Quoting hydrus:
What happens when we run out of Greek letters?..Latin maybe..?..


We already use Latin, so I dunno. Cyrillic, or maybe Arabic?
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Quoting Orcasystems:


I don't know which one... but I am sure tired of them running over my house to get there.
the second and with it winter
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TropicalStormTomas's heading turned westward to (7.6degrees west of) NorthWest
from its previous heading of (11.2degrees west of) dueNorth
TS.Tomas's average speed moving between its last 2 reported positions increased to ~22.7mph(~36.5km/h) from its previous travel speed of ~11.7mph(~18.8km/h)
Invest91L
29Oct 12amGMT - - 8.5n52.0w - 30knots(~55.6km/h) - 1006mb - ATCF
29Oct 06amGMT - - 9.3n53.7w - 30knots(~55.6km/h) - 1006mb - ATCF
TropicalDepression21
29Oct 12pmGMT - 10.0n55.3w - 30knots(~55.6km/h) - 1003mb - ATCF
TS.Thomas
29Oct 06pmGMT - 10.8n56.8w - 35knots(~64.8km/h) - - 998mb - ATCF
29Oct 09pmGMT - 11.1n57.5w - 40mph(~64.4km/h) - . - 998mb - NHC.Adv.#1
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

Copy&paste 8.5n52.0w, 9.3n53.7w, 10.0n55.3w-10.8n56.8w, 10.8n56.8w-11.1n57.5w, 11.1n57.5w-11.6n57.6w, 11.6n57.6w-12.2n58.4w, pmv, uvf, 12.2n58.4w-13.044n59.527w into the GreatCircleMapper for a look at the headings and the distances traveled over the last 15^hours.

Using straightline projection upon the speed&heading averaged
over the 3hours spanning the last two reported positions:
~3&1/2 hours from now to GreenGarden,Barbados

^ The westernmost line-segment is the straightline projection.
Each of the 3 preceding line-segment spans 3hours between positions.
The easternmost line-segment spans 6hours between positions.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
Quoting Stormchaser2007:
Really pulling together



Looks like Tomas is getting tight there.
Wet and Windy night in Barbados.

no rain here as yet, light overcast.
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Member Since: September 27, 2007 Posts: 1 Comments: 21407
Quoting flsky:

What can one say about this post. Sheesh


Agreed. The blog may have at it. How are ya, Sky?
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Gotta have that one runner that zooms out the whole image, blahh.

Member Since: January 30, 2010 Posts: 0 Comments: 3259
Member Since: September 27, 2007 Posts: 1 Comments: 21407
251. flsky
Quoting uncljbnd:
I will give my left nut to have this go to Nicaragua. I apologize to any Nicaraguans to might get screwed, but damnit, I have a carribean cruise leaving next friday from Miami and the first stop is the DR.

Further west suits me just fine.


What can one say about this post. Sheesh
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Really pulling together


Member Since: June 9, 2007 Posts: 4 Comments: 15920
Quoting TORMENTOSO83:
I don't understand,if there's a trof affecting PR, then TS Shary and behind it is a cold front,..., why the projected path is almost due WEST?

THE GFS...ECMWF...AND GFDL ALL
SUPPORT A RELATIVELY STRONG MID-LEVEL RIDGE NORTH OF THE GREATER
ANTILLES AND SHOW TOMAS MOVING GENERALLY WESTWARD ACROSS THE
SOUTH-CENTRAL CARIBBEAN SEA.
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Member Since: September 27, 2007 Posts: 1 Comments: 21407
Quoting pottery:

Oh Yeah!
Genuine with a Capital i to boot.
Little snappers and angels all over.
Only slightly used....



ewwwwww
Member Since: October 1, 2007 Posts: 81 Comments: 26511
I don't understand,if there's a trof affecting PR, then TS Shary and behind it is a cold front,..., why the projected path is almost due WEST?
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Quoting hydrus:
According to the long range forecasts, those are just the little ones you have been getting...Wait until the medium and large troughs come to your house, you will need a steam shovel just to step through your front door...:0


Its ok as long as the temp stays around 10C. The ski slopes are getting hammered already.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting hydrus:
According to the long range forecasts, those are just the little ones you have been getting...Wait until the medium and large troughs come to your house, you will need a steam shovel just to step through your front door...:0

Will serve him right too.
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Quoting bluenosedave:


I said it in July, and I will say it again. This season is headed for Greek letters. Look at the next wave heading off of Africa, if you have any doubt. It's all phenomenal, and I continue to give my best wishes to the people of Haiti, who don't need any more grief.
What happens when we run out of Greek letters?..Latin maybe..?..
Member Since: September 27, 2007 Posts: 1 Comments: 21407
241. kwads
Quoting stormwatcherCI:
That's what it looks like. Is Barbados mountainous ?


Barbados is very Flat
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Quoting Grothar:


Boy, you can't say anything on this blog without getting ripped. LOL How you doing PSL?


LMBO! Doing good, my friend. And you?
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Tomas is Big!!!
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238. HadesGodWyvern (Mod)
Tropical Cyclone Warning Center Perth
Tropical Cyclone Advice #1
TROPICAL LOW 01U
9:00 AM WST October 30 2010
======================================

At 8:00 am WST, Tropical Low (1002 hPa) located at 7.5S 96.0E or 530 km north of Cocos Island and moving west at 5 knots has sustained winds 30 knots of with gusts of 45 knots.

Dvorak Intensity: D2.5/2.5D1.5/1.5/24HRS

The low is forecast to develop into a tropical cyclone today or early on Sunday. Although it is currently moving westwards, it is expected to take a southwards turn, and is likely to pass close to Cocos Island on Tuesday. Conditions are favorable for intensification and Cocos Island is at risk of impact from a Severe Tropical Cyclone.

Gales are not expected on the islands during the weekend, but may develop by sunrise on Monday as the system moves closer and intensifies.

Tropical Cyclone Watches
========================
A Cyclone WATCH has been declared for a developing tropical low for the Cocos (Keeling) Islands.

Forecast and Intensity
======================
12 HRS: 7.9S 94.9E - 40 knots (CAT 1)
24 HRS: 8.2S 94.5E - 50 knots (CAT 2)
48 HRS: 9.3S 95.2E - 70 knots (CAT 3)
72 HRS: 11.2S 95.9E - 85 knots (CAT 3)

Additional Information
=========================
The system has significantly improved organisation over the last 24 hours, despite continuing moderate shear. High SSTs are likely assisting the low to overcome the shear, and low to mid level curvature of the cloud lines has improved markedly in microwave imagery together with a consolidation of the central overcast. At 00Z I have a position near 7.5S 96.0E. The SSMI/S image at 2231Z was particularly useful but this position also appears to place the LLCC in a position relative to the CDO that is generally consistent with amount of shear indicated in CIMSS satellite wind analyses, and with the 0030 MTSAT VIS image that has become available since I analysed that position.

Using a shear pattern gives a DT of around T3.0 but the MET is at 2.5 based on a D+ 24 hour trend and yesterdays assignment of T1.0 at 00Z. The rules will limit the FT to 2.5 and this is the assigned CI. The 1530Z ASCAT pass indicated 30 knot winds in the SW quadrant [the only sector it sampled but also the sector with the greatest convection], and the intensity is analysed as being 30 knots at 00Z consistent with the Dvorak analysis. Given the rate of development over the last 24 hours the system is likely to reach cyclone intensity later today.
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Quoting hydrus:
Only if there genuine..I am a stickler for quality.

Oh Yeah!
Genuine with a Capital i to boot.
Little snappers and angels all over.
Only slightly used....
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Quoting Orcasystems:


I don't know which one... but I am sure tired of them running over my house to get there.
According to the long range forecasts, those are just the little ones you have been getting...Wait until the medium and large troughs come to your house, you will need a steam shovel just to step through your front door...:0
Member Since: September 27, 2007 Posts: 1 Comments: 21407
"TOMAS IS BENEFITING FROM EXCELLENT UPPER-LEVEL OUTFLOW IN ALMOST ALL
QUADRANTS...AND THE CYCLONE APPEARS AS THOUGH IT IS GOING THROUGH A
PERIOD OF RAPID INTENSIFICATION."
Member Since: June 9, 2007 Posts: 4 Comments: 15920
This does not look good for us in Jamaica. 5 days from now we could be severely affected by Tomas. We still have damaged roads, places underwater and people homeless from just a Tropical Storm Nicole. Now Tomas seems to be heading our way. Most models seems to support this.
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Quoting hydrus:
Those are some ugly damn model runs...


I said it in July, and I will say it again. This season is headed for Greek letters. Look at the next wave heading off of Africa, if you have any doubt. It's all phenomenal, and I continue to give my best wishes to the people of Haiti, who don't need any more grief.
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231. JRRP
to me Tomas is moving W or WNW
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Quoting pottery:

I have a Containerload of a Special Shower curtains available, for Florida residents only.
Interested?
Only if there genuine..I am a stickler for quality.
Member Since: September 27, 2007 Posts: 1 Comments: 21407
Quoting hydrus:
one of these troughs should lift Tomas out of the Caribbean. Which one i,m not sure.


I don't know which one... but I am sure tired of them running over my house to get there.
Member Since: October 1, 2007 Posts: 81 Comments: 26511

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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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