Strengthening Tomas headed for the Lesser Antilles

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

Share this Blog
2
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 878 - 828

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19Blog Index

Member Since: Posts: Comments:
000
WTNT41 KNHC 301501
TCDAT1
HURRICANE TOMAS DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010
1100 AM AST SAT OCT 30 2010

AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING TOMAS
THIS MORNING FOUND MAXIMUM 700 MB FLIGHT-LEVEL WINDS OF 68 KT IN
THE SOUTHEAST QUADRANT ALONG WITH SEVERAL 64-66 KT RELIABLE SFMR
WINDS. IN ADDITION...A DROPSONDE IN THE NORTHEAST EYEWALL INDICATED
A SURFACE WIND OF 72 KT. HOWEVER...THE BOUNDARY-LAYER WIND PROFILES
SUGGEST A SLIGHTLY LESSER SURFACE WIND SPEED ESTIMATE OF AROUND 66
KT. A COMBINATION OF THIS DATA EASILY SUPPORTS A 65-KT HURRICANE...
AND TOMAS HAS BEEN UPGRADED ACCORDINGLY.

THE INITIAL MOTION ESTIMATE IS 290/13. THE LATEST RECON FIX
POSITIONS HAVE COME IN RIGHT ON THE PREVIOUS ADVISORY TRACK.
UPPER-AIR DATA FROM SAN JUAN REVEALED 30-METER 500 MB HEIGHT
INCREASES DURING THE PAST 24 HOURS...WHICH CLEARLY INDICATES THAT
MID-LEVEL RIDGING TO THE NORTH OF TOMAS HAS STARTED AS THE
DEEP-LAYER TROUGH THAT HAS CAPTURED HURRICANE SHARY LIFTS RAPIDLY
TO THE NORTHEAST AWAY FROM THE CARIBBEAN REGION. LOW- TO MID-LEVEL
RIDGING IS FORECAST BY ALL OF THE GLOBAL MODELS TO CONTINUE
BUILDING WESTWARD ACROSS THE LESSER AND GREATER ANTILLES FOR THE
NEXT 72-96 HOURS. THIS SHOULD GRADUALLY FORCE TOMAS ON A MORE
WESTERLY TRACK...ESPECIALLY AFTER 48 HOURS. HOWEVER...BY DAY 5...A
BROAD MID-TROPOSPHERIC TROUGH CURRENTLY LOCATED ALONG THE U.S. WEST
COAST IS FORECAST TO MOVE EASTWARD INTO THE CENTRAL U.S. BY DAYS
2-3 AND THEN DIG MORE SOUTHEASTWARD AFTER THAT...AND INTO THE GULF
OF MEXICO AND SOUTHEASTERN MEXICO BY DAY 5. THIS IS EXPECTED TO
RESULT IN A SIGNIFICANT EROSION OF THE WESTERN PORTION OF THE RIDGE
AND A WEAKENING OF THE STEERING CURRENT ACROSS THE WESTERN AND
CENTRAL CARIBBEAN SEA. THIS WEAK FLOW REGIME SHOULD ALLOW TOMAS TO
SLOW DOWN AND GRADUALLY MOVE NORTHWARD. THE OFFICIAL FORECAST TRACK
IS JUST AN UPDATE AND EXTENSION OF THE PREVIOUS ADVISORY TRACK...
AND REMAINS ALONG THE SOUTHERN EDGE OF THE NHC GUIDANCE ENVELOPE.

TOMAS HAS DEVELOPED A 30-40 NMI DIAMETER EYE NOTED IN RECENT RADAR
IMAGES FROM MARTINIQUE. THE UPPER-LEVEL OUTFLOW PATTERN IS WELL
ESTABLISHED AND CONTINUES TO IMPROVE. A COMBINATION OF THE
AFOREMENTIONED FEATURES ALONG WITH DEEP WARM WATER AHEAD OF THE
CYCLONE SHOULD RESULT IN CONTINUED STRENGTHENING FOR THE NEXT 24
HOURS OR SO. AFTER THAT...HOWEVER...WESTERLY 300 MB WINDS ARE
EXPECTED TO UNDERCUT THE IMPRESSIVE OUTFLOW LAYER AND INDUCE SOME
SHEAR ON TOMAS...WHICH MAY HALT THE INTENSIFICATION PROCESS.
USUALLY WITH WESTERLY SHEAR COMES DRY AIR MID-LEVEL AIR...AND THIS
INHIBITING FACTOR WAS CLEARLY INDICATED IN UPPER-AIR DATA WEST OF
65W LONGITUDE THIS MORNING. BY 72 HOURS...ENVIRONMENTAL CONDITIONS
ARE EXPECTED TO IMPROVE AS TOMAS SLOWS DOWN...AND A INTENSIFICATION
IS EXPECTED TO RESUME. THE OFFICIAL INTENSITY FORECAST IS ABOVE THE
SHIPS/LGEM MODELS...AND IS SIMILAR TO THE PREVIOUS FORECAST AND
LAST TWO GFDL MODEL RUNS...WHICH MAKES A TOMAS A MAJOR HURRICANE
SOUTH OF HISPANIOLA.

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/1500Z 13.3N 60.7W 65 KT
12HR VT 31/0000Z 13.8N 62.5W 75 KT
24HR VT 31/1200Z 14.4N 64.8W 80 KT
36HR VT 01/0000Z 14.8N 67.2W 80 KT
48HR VT 01/1200Z 15.2N 69.2W 85 KT
72HR VT 02/1200Z 15.6N 72.3W 90 KT
96HR VT 03/1200Z 16.0N 74.0W 100 KT
120HR VT 04/1200Z 16.5N 75.0W 100 KT

$$
FORECASTER STEWART
Member Since: Posts: Comments:
The eye isn't perfect but definitely discernibleLink
Member Since: Posts: Comments:
The ECMWF does not show Tomas very well..Link
Member Since: September 27, 2007 Posts: 1 Comments: 21416

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Quoting Patrap:
12z Early Cycle NHC model tracks
Tomas
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)







They're flip-flopping again..........Here we go.
Member Since: Posts: Comments:
Theres a few more TOMAS striking Barbados Vids on Utube this morning,,,
Member Since: Posts: Comments:
12z Early Cycle NHC model tracks
Tomas
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)





Member Since: Posts: Comments:
Quoting Patrap:
Tomas in Barbados





Great video Pat, our first peek of Tomas' fury.
Member Since: Posts: Comments:
Quoting afj3:
Anybody want to guess what's in store for Jamaica?

Tropical Storm Tomas is expected to become a major Hurricane east of Jamaica on Thursday.
All interests are, therefore, advised to pay close attention to Releases issued by the Meteorological Service. From Met service JA
Member Since: Posts: Comments:
Quoting hydrus:
Wuzup Gro..!983 was a cool year for me though. Traveled a lot and met some great people...If there is an eye it is not well formed..


Cat 1 canes don't have fully developed eyes yet, once it gets to Cat 2 we will see one.
Member Since: Posts: Comments:
Quoting afj3:
Anybody want to guess what's in store for Jamaica?


DOOM
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting Grothar:


Wow, all the way to 1983? Everthing must have still been in black & white. (Morning, hydrus)
Wuzup Gro..1983 was a cool year for me though. Traveled a lot and met some great people...If there is an eye it is not well formed..
Member Since: September 27, 2007 Posts: 1 Comments: 21416
858. afj3
Quoting cat5hurricane:

Not bright sunshine filled days, that's for sure. lol

Oh Lord. Not good!
Member Since: Posts: Comments:
Path shifted south a bit.
Member Since: Posts: Comments:
854. afj3
Anybody want to guess what's in store for Jamaica?
Member Since: Posts: Comments:
Quoting goldmind:
the eye approaching Saint Vincent and the Grenadines

http://www.meteo.fr/temps/domtom/antilles/pack-public/animation/animMOSAIC2.html


Thanks for the Address, I couldn;t pick out the eye on sat loops.
Member Since: Posts: Comments:
Quoting hydrus:
What makes me laugh is back in 1983, I would wait for what seemed like a year for one of these storms to form so I could track and observe it. Now it is hard sometimes just to keep up with the current readings. There were only 3 hurricanes and one tropical storm that year..Tomas looking a little off kilter at the moment..


Wow, all the way to 1983? Everthing must have still been in black & white. (Morning, hydrus)
Member Since: Posts: Comments:
Quoting reedzone:


Lenny with the big ear traveled, east. I was talking about storms moving west :P


LOL. Strange, storm that one. and powerful, too.
Member Since: Posts: Comments:
Quoting cat5hurricane:
Two canes simultaneously a day before Halloween. How about that.
What makes me laugh is back in 1983, I would wait for what seemed like a year for one of these storms to form so I could track and observe it. Now it is hard sometimes just to keep up with the current readings. There were only 3 hurricanes and one tropical storm that year..Tomas looking a little off kilter at the moment..
Member Since: September 27, 2007 Posts: 1 Comments: 21416
I wonder what happened to Recon? They haven't reported any HDOB data since 10:01a.m EDT.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Grothar:


How could you forget Lenny?



Lenny with the big ear traveled, east. I was talking about storms moving west :P
Member Since: Posts: Comments:
Quoting reedzone:
This is the best storm I could find that traveled across the Caribbean so late in the season, this is 1895


It's just rare and not likely for Tomas to reach the Western Caribbean without getting pulled.


How could you forget Lenny?

Member Since: Posts: Comments:
Member Since: Posts: Comments:

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Forecast Discussion for Shary:

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM
HURRICANE SHARY DISCUSSION NUMBER 7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL202010
1100 AM AST SAT OCT 30 2010

SHARY REMAINS A SMALL TROPICAL CYCLONE LOCATED JUST TO THE EAST OF A
STRONG COLD FRONT. RECENT MICROWAVE IMAGES INDICATE THAT
SHARY HAS MAINTAINED A SMALL EYE...ESPECIALLY IN THE 85-GHZ
CHANNEL. ALTHOUGH INFRARED IMAGERY SUGGESTS THAT DEEP CONVECTION
HAS BECOME LESS SYMMETRIC DURING THE PAST FEW HOURS...SHARY IS BEING
HELD AT HURRICANE STRENGTH FOR THIS ADVISORY DUE TO THE MICROWAVE
PRESENTATION AND THE FAST FORWARD SPEED OF THE SYSTEM. THE CYCLONE
WILL LIKELY WEAKEN TODAY AS IT MOVES INTO EVEN STRONGER SHEAR AND
OVER COOLER WATER. THE GFS AND ECMWF MODELS SHOW SHARY INTERACTING
WITH THE FRONT BY THIS AFTERNOON AND BECOMING ABSORBED ALONG THE
BOUNDARY IN ABOUT 24 HOURS. ON THE OTHER HAND...THE UKMET AND
NOGAPS MODELS SHOW LESS INTERACTION WITH THE FRONT AND MOVE SHARY
SLOWLY EASTWARD. THE LATTER SOLUTIONS APPEAR UNREALISTIC GIVEN THE
CURRENT PROXIMITY TO THE FRONT...AND THE OFFICIAL FORECAST FOLLOWS
THE USUALLY MORE RELIABLE GFS/ECMWF MODELS.

THE TROPICAL CYCLONE IS RACING NORTHEASTWARD WITHIN DEEP-LAYER
SOUTHWESTERLY FLOW...AND THE LATEST INITIAL MOTION ESTIMATE IS
055/35. THIS MOTION IS FORECAST TO CONTINUE UNTIL SHARY BECOMES
ABSORBED ALONG THE FRONT. THE OFFICIAL TRACK FORECAST IS ADJUSTED
A LITTLE TO THE LEFT OF THE PREVIOUS ONE AND IS NEAR THE
MULTI-MODEL CONSENSUS...TVCN.

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/1500Z 35.9N 55.6W 65 KT
12HR VT 31/0000Z 38.0N 50.5W 55 KT...POST-TROP/EXTRATROP
24HR VT 31/1200Z...DISSIPATED

$$
FORECASTER CANGIALOSI

NNNN
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Th NAM is rather interesting.I noticed a spin over Colombia yesterday, and the NAM develops it..LinkLink
Member Since: September 27, 2007 Posts: 1 Comments: 21416

Member Since: June 9, 2007 Posts: 4 Comments: 15921
19/12/5
Member Since: Posts: Comments:
...SHARY RACING NORTHEASTWARD...EXPECTED TO TRANSITION TO A
POST-TROPICAL STORM BY TONIGHT...

SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...35.9N 55.6W
ABOUT 580 MI...935 KM ENE OF BERMUDA
ABOUT 755 MI...1220 KM S OF CAPE RACE NEWFOUNDLAND
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/HR
PRESENT MOVEMENT...NE OR 55 DEGREES AT 40 MPH...65 KM/HR
MINIMUM CENTRAL PRESSURE...989 MB...29.21 INCHES
Member Since: September 2, 2009 Posts: 130 Comments: 21194




Finally updated.. :)
Member Since: Posts: Comments:
Tomas in Barbados



Member Since: Posts: Comments:

Viewing: 878 - 828

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Overcast
65 °F
Overcast