Strengthening Tomas headed for the Lesser Antilles
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
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Kman now it will only go over 1 island, not much impeding him.
BTW....My stepfathers name was Tomas and I hated him!!!
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AOI
TS BUSTED FORECAST ALIBI
we were listening to the radio feed, it sounded like a bunch of trees down and aluminum roofs off but not much else.
I also wouldn't completely trust the validity of this data.
The 995mb reading for minimum surface pressure was based off a dropsonde that was supposedly dropped in the eye. They found 29mph surface winds in the eye.
000
URNT12 KNHC 301515 CCA
VORTEX DATA MESSAGE AL212010
A. 30/1406Z
B. 13 deg 03 min N
060 deg 26 min W
C. 700 mb 3047 M
D. 53 KT
E. 124 deg 07 NM
F. 244 deg 45 KT
G. 134 deg 37 NM
H. 995 MB
I. -
J. -
K. -
L. -
M. -
N. -
O. -
P. AF300 0222A TOMAS OB 16
MAX FL LVL WIND OUT BOUND 67 KT N QUAD 1416Z
MISSING DATA I THRU O BECAUSE OF COM PROBLEMS
Right now, a close call for Jamaica, possibly turning North as near as 50 miles East and swinging North near the tip of the Tiburon peninsula. This is very far out in time as you know and will depend on the evolution of the trough / ridge interaction late next week.
As you know long range track forecast errors by even the professionals can be off by hundreds of miles so take this with a grain of salt for now. I do however see Tomas making it quite deep into the central Caribbean before lifting out. The high over the GOM continues to push East and the last few satellite frames seem to suggest that the heading may have flattened a bit to 285 from 290 degrees.
The eye is clearing out quickly and headed directly for St Vincent. They will take a hard blow from this.
That's what the NHC is thinking, but the possible curve at the end of the forecast period is leaving things very ify.
Thanks, will keep an eye on it for now.
St Vincent has 4000 foot peaks. Some disruption to the core will result but not enough to do a lot of damage to the circulation.
Hurricane Tomas' Eye is about ready to hit St Vincent
(Hope I'm OK posting this stuff here :) )
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