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: 528 - 478

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

528. JRRP
no puedo dormir sabiendo que hay un ciclon amenazandonos
Member Since: Posts: Comments:
So we still in for another set of pounding...
Member Since: Posts: Comments:
can someone please post the link to the barbados radar - have looked everywhere - can't find it.
Member Since: Posts: Comments:
Getting a bit of rain now and the mind stirrings of a gentle breeze.
Member Since: August 21, 2010 Posts: 0 Comments: 96
Thanks Kori!!

All I got is WOW!!
Member Since: Posts: Comments:
523. JLPR2
Well, back to bed. :]
Member Since: September 4, 2007 Posts: 7 Comments: 8506
522. JLPR2
LOL! I came to check on Tomas and find out Shary is a cane? O.o LOL

That was the last thing I expected.
Member Since: September 4, 2007 Posts: 7 Comments: 8506
Quoting SherwoodSpirit:
Between watching various links on Tomas, watching his pressure bomb out via HuracandelCaribe's updates (thanks!), and now gazing at Shary in amazement, because I really thought she couldn't do what she's doing... I'm staying up WAY TOO LATE! haha
This blog eats up a lot of my life during hurricane season. :)


Likewise...it's addictive. Just one more advisory... :P
Member Since: Posts: Comments:
0k 994
Member Since: August 12, 2007 Posts: 0 Comments: 97
Between watching various links on Tomas, watching his pressure bomb out via HuracandelCaribe's updates (thanks!), and now gazing at Shary in amazement, because I really thought she couldn't do what she's doing... I'm staying up WAY TOO LATE! haha
This blog eats up a lot of my life during hurricane season. :)
Member Since: Posts: Comments:
the official pressure will be between 991 and 994
Member Since: August 12, 2007 Posts: 0 Comments: 97
000
WTNT41 KNHC 300849
TCDAT1
TROPICAL STORM TOMAS DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL212010
500 AM AST SAT OCT 30 2010

THE SATELLITE PRESENTATION OF TOMAS HAS IMPROVED OVERNIGHT. AN
EARLIER GAP IN THE DEEP CONVECTION NEAR THE CENTER HAS FILLED IN
...AND THE OUTFLOW REMAINS EXCELLENT. ALSO...IMAGERY FROM THE RADAR
ON MARTINIQUE AND A 0624 UTC TRMM PASS SUGGEST THAT AN EYEWALL
MAY BE FORMING. BASED ON THESE TRENDS...THE INITIAL INTENSITY IS
RAISED TO 60 KT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS
SCHEDULED TO INVESTIGATE TOMAS LATER THIS MORNING TO GET BETTER
INFORMATION ON THE STRUCTURE AND INTENSITY OF THE CYCLONE. DURING
THE NEXT DAY OR SO...CONDITIONS APPEAR FAVORABLE FOR CONTINUED
INTENSIFICATION. IN FACT...THE SHIPS MODEL RAPID INTENSITY INDEX
SHOWS A NEARLY 60 PERCENT CHANCE OF A 25-KT INCREASE IN 24 HOURS.
BEYOND THAT TIME...THE SHIPS MODEL...BASED ON GFS MODEL FIELDS...
SHOWS AN INCREASE IN SOUTHWESTERLY SHEAR...WHICH SHOULD SLOW THE
RATE OF INTENSIFICATION SOMEWHAT. AFTER 72 HOURS...THE SHEAR MAY
RELAX AND ALLOW FOR FURTHER INTENSIFICATION. THE NEW OFFICIAL
FORECAST REFLECTS THIS THINKING AND IS ABOVE ALL OF THE RELIABLE
INTENSITY MODELS THROUGH THE PERIOD.

THE CENTER APPEARS TO BE LOCATED A LITTLE NORTH OF THE PREVIOUS
FORECAST TRACK BASED ON THE RECENT TRMM PASS...AND THE INITIAL
MOTION ESTIMATE IS 300/13. TOMAS IS CURRENTLY BEING STEERED
WEST-NORTHWESTWARD TO THE SOUTH OF A MID-LEVEL RIDGE THAT EXTENDS
FROM THE CENTRAL ATLANTIC INTO THE NORTHEASTERN CARIBBEAN. AS A
MID-LEVEL TROUGH CURRENTLY SITUATED OVER THE SOUTHWESTERN ATLANTIC
LIFTS OUT...ANOTHER RIDGE WILL BUILD IN NORTH OF TOMAS...WHICH
SHOULD IMPART A WEST-NORTHWESTWARD OR WESTWARD MOTION THROUGH 72
HOURS. BEYOND THAT TIME...THE GLOBAL MODELS SHOW A LONGWAVE TROUGH
MOVING INTO EASTERN NORTH AMERICA AND A CUTOFF LOW DEVELOPING IN
THE GULF OF MEXICO. THIS SHOULD WEAKEN THE RIDGE AND CAUSE A
DECREASE IN FORWARD SPEED LATE IN THE PERIOD...AND POTENTIALLY A
NORTHWARD TURN. THE TRACK MODEL ENVELOPE HAS SHIFTED NORTHWARD WITH
THIS CYCLE...BUT THE FORECAST IS ADJUSTED ONLY SLIGHTLY NORTHWARD
OUT OF RESPECT FOR THE GFS...UKMET...AND ECMWF MODELS WHICH REMAIN
FARTHER SOUTH. LATE IN THE PERIOD...THE FORWARD SPEED IS QUITE SLOW
DUE TO THE LARGE UNCERTAINTY IN THE TIMING AND SHARPNESS OF THE
POTENTIAL NORTHWARD TURN.

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/0900Z 12.9N 59.5W 60 KT
12HR VT 30/1800Z 13.5N 61.3W 70 KT
24HR VT 31/0600Z 14.1N 63.7W 80 KT
36HR VT 31/1800Z 14.6N 65.9W 85 KT
48HR VT 01/0600Z 15.1N 68.1W 90 KT
72HR VT 02/0600Z 15.5N 71.5W 90 KT
96HR VT 03/0600Z 16.0N 73.5W 100 KT
120HR VT 04/0600Z 16.5N 74.5W 100 KT

$$
FORECASTER BRENNAN
Member Since: Posts: Comments:
Interesting NHC discussion on classifying Shary as a hurricane:

000
WTNT45 KNHC 300836
TCDAT5
HURRICANE SHARY DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL202010
500 AM AST SAT OCT 30 2010

SHARY POSES A BIT OF A CONUNDRUM THIS MORNING. THE LATEST SATELLITE
IMAGES SHOW THAT DEEP CONVECTION HAS CONTINUED TO GROW AND BECOME
MORE SYMMETRIC NEAR THE CENTER. IN ADDITION...TRMM PASSES FROM
OVERNIGHT INDICATED THE DEVELOPMENT OF A SMALL EYE FEATURE IN THE
37-GHZ CHANNEL. WHILE DVORAK T-NUMBERS ARE HIGHER THAN EARLIER
...THEY ARE FAR FROM SUPPORTING HURRICANE INTENSITY...ALTHOUGH
THESE SATELLITE ESTIMATES ARE CLEARLY NOT HANDLING THIS SYSTEM WELL.
THE DEEPENING OF CONVECTION AND THE EYE FEATURE IN MICROWAVE IMAGERY
SUGGEST A FURTHER ORGANIZATION OF SHARY AND AT LEAST A NOMINAL
INCREASE IN WIND SPEED FROM THE 60 KT OBSERVED FROM THE AIRCRAFT.
NORMALLY A 5-KT WIND ADJUSTMENT WOULD NOT REQUIRE THIS MUCH
DISCUSSION...BUT A CHANGE IN STATUS DOES COMPLICATE MATTERS. IT IS
HARD TO DISCOUNT THE LARGE CONVECTIVE INCREASE AND THE SIGNIFICANT
IMPROVEMENT ON MICROWAVE IMAGES SINCE THE AIRCRAFT DEPARTED...THUS
THE INITIAL WINDS ARE NUDGED UPWARD TO 65 KT. THIS IS A GOOD CASE
OF A SMALL HURRICANE THAT WAS VERY UNLIKELY TO BE OBSERVED BEFORE
THE RECENT ERA WHEN MICROWAVE SATELLITE IMAGERY WAS AVAILABLE.

THE TRMM PASSES AND GEOSTATIONARY SATELLITE IMAGERY INDICATE THAT
SHARY HAS ACCELERATED CONSIDERABLY AND IS NOW SPEEDING
NORTHEASTWARD AT ABOUT 30 KT. THIS GENERAL TRACK IS EXPECTED TO
CONTINUE WHILE THE SYSTEM REMAINS ENTRENCHED IN SOUTHWESTERLY
MID-LATITUDE FLOW. A COLD FRONT RAPIDLY APPROACHING SHARY IS
EXPECTED TO CAUSE THE HURRICANE TO BECOME AN EXTRATROPICAL LOW
WITHIN 12 TO 24 HOURS BEFORE ABSORBING THE CYCLONE BY 36 HOURS. THE
GLOBAL MODELS ARE IN GOOD AGREEMENT ON THIS TRANSITION...AND THE
NEW FORECAST IS ADJUSTED TO THE RIGHT TO ACCOUNT FOR THE INITIAL
MOTION AND THE LATEST TRACK GUIDANCE. SHARY SHOULD BEGIN TO WEAKEN
SOON DUE TO INCREASING SHEAR AS IT MOVES OVER WATERS COOLER THAN
76F. THE INTENSITY FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS
ONE AFTER ACCOUNTING FOR THE SLIGHTLY HIGHER INITIAL WINDS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 30/0900Z 33.6N 59.4W 65 KT
12HR VT 30/1800Z 35.7N 54.6W 55 KT
24HR VT 31/0600Z 38.5N 48.0W 45 KT...POST-TROP/EXTRATROP
36HR VT 31/1800Z...ABSORBED BY A COLD FRONT

$$
FORECASTER BLAKE
Member Since: Posts: Comments:
Member Since: August 12, 2007 Posts: 0 Comments: 97
991.4
Member Since: August 12, 2007 Posts: 0 Comments: 97
Quoting flibinite:
Thank you both... I'll have to figure out how to convert that to millibars. :-)


Random website, but should help you.
Link
Member Since: Posts: Comments:
Shary's a hurricane!
Member Since: Posts: Comments:
i think wind shift is starting
Member Since: August 12, 2007 Posts: 0 Comments: 97
991.8
Member Since: August 12, 2007 Posts: 0 Comments: 97
Thank you both... I'll have to figure out how to convert that to millibars. :-)
Member Since: Posts: Comments:
992.1
when will it stop
Member Since: August 12, 2007 Posts: 0 Comments: 97
Link, courtesy of Huracandel. :)
Link
Member Since: Posts: Comments:
Link
Member Since: August 12, 2007 Posts: 0 Comments: 97
A stunningly quick drop... where are you getting this information from, HuracandelCaribe?

Thank you for it, though.
Member Since: Posts: Comments:
504. KBH
hey guys what's the latest on the location of centre of Tomas? is it still ESE or moving north?
Member Since: Posts: Comments:
992.4
Member Since: August 12, 2007 Posts: 0 Comments: 97
992.8 still dropping
Member Since: August 12, 2007 Posts: 0 Comments: 97
pressure still dropping 993.1
Member Since: August 12, 2007 Posts: 0 Comments: 97
hey guys I am now in Victoria BC and no longer in Cayman. All my family are still there and we are having a hard time with this one. Can anyone comment on its threat to Cayman? Caymanians are hurricane people and used to some weather but its the recent example of Ivan and its devastation that worries us all...
Member Since: Posts: Comments:
I cant go to bed until the wind shift, till then I will know how strong is this storm, because all this weather stations are located in the south of the island which blocks the wind from the north
Member Since: August 12, 2007 Posts: 0 Comments: 97
wow 993.8
Member Since: August 12, 2007 Posts: 0 Comments: 97
apparently the weather station i was following is down. the other stations are now reporting wnw winds pressure 994.1 and dropping
Member Since: August 12, 2007 Posts: 0 Comments: 97
496. ackee
If Hati get hit buy Tomas it be one for the record books getting hit by equake and disease out break and possible a hurricane in one year cant remember country getting hit by so much disater in a year.
Member Since: Posts: Comments:
Tomas is probably a Hurricane right now
Member Since: Posts: Comments:
Quoting aspectre:
454 HuracandelCaribe " [eastern Caribbean map] "



Copy&paste puj, bqn, pse, vqs, cpx, vij, ngd, axa, sxm, sbh, stx, bbq, sab, eux, skb, nev, anu, mni, ptp, dom, gbj, fdf, uvf, bgi, svd, ciw, gnd, tab, pos, pmv, bla, ccs, bon into the GreatCircleMapper for the names of those airports and where they are located.


Ok my last post, but I gotta say, Aspectre, you and that Great circle mapper are top flight! I've loved your input through this season and through your input I've learned to use that site well!! Props to you!
Member Since: Posts: Comments:
Quoting HuracandelCaribe:
pressure still dropping 997.9

Link
now 995.1 still dropping
Member Since: Posts: Comments:
pressure still dropping 996.8
Member Since: August 12, 2007 Posts: 0 Comments: 97
pressure still dropping 997.2
Member Since: August 12, 2007 Posts: 0 Comments: 97
Quoting KoritheMan:


No immediate poleward movement is likely. Water vapor imagery shows the southward extension of a broad mid-oceanic trough is quickly retreating northeastward, which will allow for continued extension of the subtropical ridge to the north.

Granted, I highly doubt Tomas makes it all the way into the Gulf of Mexico, but it could easily reach the latitude of eastern Jamaica before making the recurvature.


My thoughts as well. Jamaica, and god forbid hispainola should keep a very close eye on Tomas. My thoughts are that we all should make a donation to Portlight Strategies, Inc, and possibly save a life! Those folks in Haiti have sure seen their share of calamity in 2010, and it is my deepest hopes and prayers they somehow make it thru Tomas unscathed! But if not, at least Portlight will be there!! Give what ya can, and if ya can't give any cash or other necessities,.. at least give a prayer to those poor souls! Well there's my pedestal moment, now off to bed! Goodnight Tom, Reed, and Alfa, and whomever else may still be on at this ungodly hour:-)
Member Since: Posts: Comments:
Also to note, there is a "eye" like feature. I believe visible will show an actual eye when the time comes this morning.

Member Since: Posts: Comments:
pressure still dropping 997.5
Member Since: August 12, 2007 Posts: 0 Comments: 97
I believe we have a very good chance at getting Hurricane Tomas at 5 a.m.

Member Since: Posts: Comments:
pressure still dropping 997.9
Member Since: August 12, 2007 Posts: 0 Comments: 97
http://www.wunderground.com/cgi-bin/findweather/getForecast?query=13.063%2C-59.504#PWS


barbados stations
Member Since: August 12, 2007 Posts: 0 Comments: 97
pressure is dropping fast
Member Since: August 12, 2007 Posts: 0 Comments: 97
Quoting Bubu77:
Je sens que demain en Martinique on va avoir une très mauvaise surprise !!

La population est à peine prévenue par Météo France !!!!


Very very bad !!!

Perhaps
Member Since: Posts: Comments:
454 HuracandelCaribe " [eastern Caribbean map] "



Copy&paste puj, bqn, pse, vqs, cpx, vij, ngd, axa, sxm, sbh, stx, bbq, sab, eux, skb, nev, anu, mni, ptp, dom, gbj, fdf, uvf, bgi, svd, ciw, gnd, tab, pos, pmv, bla, ccs, bon into the GreatCircleMapper for the names of those airports and where they are located.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
center over Barbados winds just dropped to 12kmh pressure 998 and dropping
Member Since: August 12, 2007 Posts: 0 Comments: 97
479. ackee
Quoting KoritheMan:


No immediate poleward movement is likely. Water vapor imagery shows the southward extension of a broad mid-oceanic trough is quickly retreating northeastward, which will allow for continued extension of the subtropical ridge to the north.

Granted, I highly doubt Tomas makes it all the way into the Gulf of Mexico, but it could easily reach the latitude of eastern Jamaica before making the recurvature.
agree dont but into quick turn NE either notice Ecmwf westerly movement seem best bet guess we see
Member Since: Posts: Comments:
Quoting thegoldenstrand:
Anyone buying almost all the models now turning Tomas into sharply to the north and northeast a couple days from now at 2AM EST update 10302010?

That would be great news for Belize and the Gulf, but... thinking it is not going to make that sharp right turn, especially if trough does not reach that far south to grab Tomas. and it should otherwise move more to the west.

Thoughts?


No immediate poleward movement is likely. Water vapor imagery shows the southward extension of a broad mid-oceanic trough is quickly retreating northeastward, which will allow for continued extension of the subtropical ridge to the north.

Granted, I highly doubt Tomas makes it all the way into the Gulf of Mexico, but it could easily reach the latitude of eastern Jamaica before making the recurvature.
Member Since: Posts: Comments:

Viewing: 528 - 478

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.