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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Further ... I cannot help but reflect on the poor guy who was put in charge of the NHC or whatever and tried to make a case for a QUIKSCAT replacement ... he was torpedoed out of office, BUT while argument was made against his position due to heavy Radar around the US and nearby, we out here still have to wait on (now) ASCAT - I understand that our local Doppler Radar funded by the EU is down at this time. I'll stop here as I don't want to be obscene ...
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Wow!!! Leave the site for a couple of days and now we are close to having a Hurricane Tomas? Uhm, what happened to the season is over...see you next year? I guess no telling mother nature what she can or cannot do! Praying this monster looking thing gets nowhere near Haiti!
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Quoting stormwatcherCI:
That's what it looks like. Is Barbados mountainous ?

No.
Gradually "tilted" from the west coast upward to the east, Atlantic coast.
A couple hundred feet at most.
The east coast is generally rocky with cliffs and reefs.
The surf there is incredible on a CALM day.
Going to be awesome tonight and tomorrow..
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wow....invest to strong tropical storm in just hours
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"AND THE CYCLONE APPEARS AS THOUGH IT IS GOING THROUGH A
PERIOD OF RAPID INTENSIFICATION."




Member Since: June 9, 2007 Posts: 4 Comments: 15877
And so we have another Rapidly Intensifying system:

000
WTNT41 KNHC 300245
TCDAT1
TROPICAL STORM TOMAS DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010
1100 PM AST FRI OCT 29 2010

AS MENTIONED IN THE 0000 UTC SPECIAL ADVISORY...THE AIR FORCE
RECONNAISSANCE AIRCRAFT REPORTED A MAXIMUM FLIGHT-LEVEL WIND OF 61
KT AND SFMR MEASUREMENTS BETWEEN 50-55 KT...ALBEIT IN SOME HEAVY
RAIN...ON THE LAST PASS THROUGH THE CENTER. DEEP CONVECTION HAS
CONTINUED TO INCREASE SINCE THAT TIME WITH A PROMINENT BAND FORMING
OVER THE WESTERN SEMICIRCLE...SO THE INITIAL INTENSITY IS BEING
RAISED TO 55 KT ON THIS ADVISORY.

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. SHIPS RI GUIDANCE IS INDICATING
AT LEAST A 40 PERCENT CHANCE OF A 30-KT INCREASE IN INTENSITY OVER
THE NEXT 24 HOURS...AND IT IS LIKELY THAT TOMAS WILL REACH
HURRICANE STRENGTH WITHIN THE NEXT 12-24 HOURS. AFTER 24
HOURS...NEARLY ALL THE INTENSITY GUIDANCE SHOWS THE INTENSITY
LEVELING OFF OR ONLY INCREASING MORE MODESTLY THROUGH 120 HOURS.
HOWEVER...GLOBAL MODEL FIELDS SHOW THE ENVIRONMENT OVER THE
CARIBBEAN BECOMING FAVORABLE FOR CONTINUED INTENSIFICATION...AND IT
IS NOT OBVIOUS AT THIS POINT WHAT MIGHT LIMIT THAT TREND. THE
OFFICIAL FORECAST CONTINUES TO SHOW STEADY STRENGTHENING TO
CATEGORY 3 STRENGTH BY DAY 4 AND REMAINS ABOVE ALL THE RELIABLE
INTENSITY MODELS.

THE CENTER APPEARED TO HAVE REFORMED TO THE NORTH EARLIER THIS
EVENING...AND THE INITIAL MOTION IS ESTIMATED AT 300/14. THE NEW
OFFICIAL TRACK FORECAST REMAINS LARGELY UNCHANGED FROM THE
PREVIOUS FORECAST...ALTHOUGH THE FIRST 12-24 HOURS OF THE TRACK
FORECAST HAVE BEEN SHIFTED A LITTLE TO THE NORTH AS AN ARTIFACT OF
THE REFORMATION OF THE CENTER. 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. THESE ARE USUALLY THE MOST
TRUSTWORTHY OF THE DYNAMICAL MODELS...AND THE OFFICIAL FORECAST
FAVORS THEIR SCENARIO...LYING JUST TO THE SOUTH OF THE MODEL
CONSENSUS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/0300Z 12.2N 58.4W 55 KT
12HR VT 30/1200Z 13.0N 60.2W 65 KT
24HR VT 31/0000Z 13.7N 62.7W 75 KT
36HR VT 31/1200Z 14.2N 65.0W 85 KT
48HR VT 01/0000Z 14.5N 67.1W 90 KT
72HR VT 02/0000Z 15.0N 71.0W 95 KT
96HR VT 03/0000Z 15.5N 74.0W 100 KT
120HR VT 04/0000Z 16.0N 76.0W 100 KT

$$
FORECASTER BERG/BROWN
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Quoting TropicalAnalystwx13:
Right now it does not look like the NHC is expecting it to recurve.
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tomas gonna be one mean sucker, i really am not convinced of that hard right kmanislander, that trough will soon lift out and tomas slip underneath there is a front coming down inthe gulf depending on when it stalls and tomas advancement i feelit will pull him just to the west side of jam and between grand cayman and cayman brac over to cuba and the bahamas.jmo
Member Since: August 14, 2008 Posts: 0 Comments: 1002
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SO is it too early to tell whether Tropical Storm Tomas will affect Costa Rica or central America?
I am from CRC.
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Quoting pottery:
Hi, Snake.
Just a sprinkle of rain here today.
It's all so confounding....


Tomas looks to be a bad one for sure. We recently discovered all five of the fire ant colonies that we had in our yard have moved into the above ground flower gardens I built two years ago. Now what would make a subterranean ant species decide that they needed to get out of the ground and into a garden 18 inches above ground? And Macon, Ga is 167 miles NW of Savannah and the ocean. :)
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...TOMAS NEARING BARBADOS...HURRICANE WARNINGS ISSUED FOR PORTIONS OF THE WINDWARD ISLANDS...
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Quoting TampaSpin:


Bro, yesterday morning there was barely a ripple of a wave in the GOM...UNREAL. I told my brother it was almost scary still....the dang water temp was 81deg...UNREAL. I got the Website graphics up if anyone wants to see the very disturbing models and all the graphics on Tomas. For those of you that read my updates....i told ya all this was coming in my last update 4 days ago.....SORRY!


That's nothing, PsychicMaria told me this 3 months ago. Nice models by the way and yes, disturbing.
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Quoting brohavwx:
Let's face it, Tomas has fooled everyone, models and all. I said that last night ... there is not much precedent (data) for this type of late season, starting low latitude in the mid-Tropics of the Atlantic to go with, and if I were the NHC I would have been a bit more cautious.

On reflection, anyone remember my question a week or so back, asking what could happen in the area of 10N 40W or there about, where the SST's have been warmest for over a month now, if conditions became more favourable for development? I guess we are seeing that now!

I remember that.
I have been watching this for a while as well.
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Action tonight in Barbados... and that is obvious.
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Wow


Member Since: June 9, 2007 Posts: 4 Comments: 15877
I have it there too stormpetrol
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Quoting pottery:

I would expect the main area of convection to pass directly over Barbados.
Not a nice prospect atall atall.
That's what it looks like. Is Barbados mountainous ?
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Complete Update



AOI
AOI AOI AOI

AOI AOI AOI

TS BUSTED FORECAST ALIBI
Member Since: October 1, 2007 Posts: 81 Comments: 26511
65 mph...997 mb.

Hurricane Warnings out.
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WTNT35 KNHC 300237
TCPAT5
BULLETIN
TROPICAL STORM SHARY ADVISORY NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL202010
1100 PM AST FRI OCT 29 2010

...SHARY EXPECTED TO PASS WELL EAST OF BERMUDA SOON...TROPICAL STORM
WARNING DISCONTINUED...



..................

WTNT31 KNHC 300242
TCPAT1
BULLETIN
TROPICAL STORM TOMAS ADVISORY NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010
1100 PM AST FRI OCT 29 2010

...TOMAS NEARING BARBADOS...HURRICANE WARNINGS ISSUED FOR PORTIONS
OF THE WINDWARD ISLANDS...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...12.2N 58.4W
ABOUT 100 MI...165 KM SE OF BARBADOS
ABOUT 205 MI...325 KM ESE OF ST. VINCENT
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/HR
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 16 MPH...26 KM/HR
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES





SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...31.9N 63.3W
ABOUT 85 MI...140 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/HR
PRESENT MOVEMENT...NE OR 50 DEGREES AT 21 MPH...33 KM/HR
MINIMUM CENTRAL PRESSURE...994 MB...29.35 INCHES


....OK got that done, now on to Tomas
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Quoting cat5hurricane:

Not anymore north of Barbados, no. I'm thinking in between them, probably a bit north of the NHC points from the 5pm EDT advisory...but still south of Barbados. Either way, Barbados will still get that ugly NE quadrant of squally weather, with hurricane gusts a possibility. Tobago will probably also see TS force winds, due to the sheer size of this thing.

That is how I am reading it as well.
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T.C.F.W
RI/21L/H/T/C1
MARK
12.13n/58.24w
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Quoting RTLSNK:


Dr. Masters covered that in his blog comments above. Paragraph 3, "Track forecast for Tomas". It gets a little busy in here during an active storm season. Sometimes questions just get overlooked, or it is still too early to tell. :)
I know, but I just wanna to know you guys opinions!!!!
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Let's face it, Tomas has fooled everyone, models and all. I said that last night ... there is not much precedent (data) for this type of late season, starting low latitude in the mid-Tropics of the Atlantic to go with, and if I were the NHC I would have been a bit more cautious.

On reflection, anyone remember my question a week or so back, asking what could happen in the area of 10N 40W or there about, where the SST's have been warmest for over a month now, if conditions became more favourable for development? I guess we are seeing that now!
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Quoting alfabob:


That image is insane. Thomas is a true oddity.
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I'm out for now.
Member Since: August 19, 2006 Posts: 0 Comments: 15807
Quoting stormwatcherCI:



Looks very menacing.

I would expect the main area of convection to pass directly over Barbados.
Not a nice prospect atall atall.
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Quoting Grothar:


You picked a heck of a time to go fishing?


Bro, yesterday morning there was barely a ripple of a wave in the GOM...UNREAL. I told my brother it was almost scary still....the dang water temp was 81deg...UNREAL. I got the Website graphics up if anyone wants to see the very disturbing models and all the graphics on Tomas. For those of you that read my updates....i told ya all this was coming in my last update 4 days ago.....SORRY!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
143. MZT
What a strange year. No strong landfalling US storms, yet many storms being named, and possibly the most storm names ever from one year becoming retired.
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142. flsky
Quoting TX2FL:
Wow this is nuts..

My best friend is living in Barbados right now, told me that at 5pm it took her 2 hours to make a 5 mile drive home from work...that the sea looked pretty angry. She lives in a first floor apartment right on the ocean..wondering what I should tell her she's from Port of Spain T&T so has never had a hurricane knocking on her door..

Tell her to get off the first floor and into a strong structure. Maybe a hotel or a government building.
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Looks very menacing.
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Quoting whybminor:
Does the 8PM fix look too far S to anyone other than me? 8PM fix has it at 11.6N but center of circ on the sat image looks to be just about even with Barbados, ie lat 13. Motion seems to have quite a northward component in it, though that may just reflect a still somewhat disorganized center. I live in SW PR so 100 NM farther north could make a big difference to us.


I have COC around 11.8N/58W displaced slightly SW from the heaviest convection, jmo tho.
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Quoting JLPR2:
AL, 21, 2010103000, , BEST, 0, 119N, 578W, 50, 999, TS

ready to break 12N before schedule
12HR VT 30/0600Z 12.0N 59.5W 55 KT


Tomas is top heavy on the NE side now and that is likely exerting some frictional pull to the North of the points a bit. Once the deep convection wraps around the track should settle down back on the points.
Member Since: August 19, 2006 Posts: 0 Comments: 15807
Quoting pottery:
Hi, Snake.
Just a sprinkle of rain here today.
It's all so confounding....


Your right... and it was not part of the plan.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting cat5hurricane:

Earlier, it exhibited a slight northwestward jog. Since then, that appeared to have ceased. I am seeing a much more west-northwesterly track now. The speed however, remains the same.

I think it's a bit deceiving looking at the Infrared loops which would make it look that way, since a lot of the heavy convection is moving to the north. But the surface center is heading WNW right now. And as the system becomes more organized, the deep thunderstorm activity should begin to wrap around the center more to form a tighter, more defined core.

So, you are seeing a track between Barbados and Tobago?
Or north of that?
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Member Since: August 14, 2008 Posts: 0 Comments: 1002
Hi, Snake.
Just a sprinkle of rain here today.
It's all so confounding....
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Quoting cat5hurricane:

The center is becoming more defined and established, as illustrated from the Microwave signatures. Earlier center reformations/jumps would have been more of an option. Now that he really tightened up, it's just a matter of time before that deep intense band of convection begins to wrap itself around the LLC to establish a nice inner-core. Should happen overnight.

Then it would become quite a different kettle of fish....
(fish being the wrong word, in this context)
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Just got a personal tweet from Jim Cantore, says he don't how far west Tomas will go, but Grand Cayman is in play!
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Quoting TORMENTOSO83:
What's the scenario for PR ???


Dr. Masters covered that in his blog comments above. Paragraph 3, "Track forecast for Tomas". It gets a little busy in here during an active storm season. Sometimes questions just get overlooked, or it is still too early to tell. :)
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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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