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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Thank you for it, though.
Link
when will it stop
Random website, but should help you.
Link
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
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
This blog eats up a lot of my life during hurricane season. :)
Likewise...it's addictive. Just one more advisory... :P
That was the last thing I expected.
All I got is WOW!!
Hi Julie. What is the situation with Tomas in Barbados? Any damage? How strong are the winds?
north
from its previous heading of (4.5degrees north of) West NorthWest
TS.Tomas's average speed moving between its last 2 reported positions increased to ~19.3mph(~31.1km/h) from its previous travel speed of ~10mph(~16.1km/h)
Invest91L
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
30Oct 06amGMT - 12.4n58.8w - 65mph(~104.5km/h) - - 997mb - NHC.Adv.#3A
30Oct 09amGMT - 12.9n59.5w - 70mph(~112.7km/h) - - 994mb - NHC.Adv.#4
Copy&paste 9.3n53.7w, 10.0n55.3w, 10.8n56.8w, 11.1n57.5w-11.6n57.6w, 11.6n57.6w-12.2n58.4w, 12.2n58.4w-12.4n58.8w, 12.4n58.8w-12.9n59.5w, bla, fdf, 12.9n59.5w-13.888n60.89w into the GreatCircleMapper for a look at the headings and the distances traveled over the last 12^hours.
Using straighline projection upon the speed&heading averaged
over the 3hours spanning the last two reported positions:
~5&1/2 hours from now to AnseCanot,St.Lucia
^ The westernmost line-segment is the straightline projection.
Ok. Stay safe. Part 2 of a hurricane is always the stronger phase and this should begin to affect you guys shortly. It looks like St. Lucia might get the brunt of the system though. I'm in Trinidad now which was initially threatened and persons here did take the warnings seriously enough. However, in St. Lucia, most people seem to be unaware of the situation that it developing this morning and very few if any preparations have been made. Worse yet, it's the annual Creole Day celebrations so many people are actually in a festive mood this weekend. It's basically too late to do anything now since the winds are beginning to increase there already and the radar shows that some awful weather is approaching.
I hope so too!
Ok, I'm gettin' punchy. I'm off to bed. Stay safe all of you in harm's way.
thanks kori
With Shary's improbable rise to hurricane status and the near certainty of Tomas' making it there, that will mean there have been five consecutive hurricanes beginning with Otto. I haven't done an exhaustive search, but a cursory glance shows that's a relatively infrequent occurrence, though not quite a rarity. It happened most recently in 1998 (six in a row, from Ivan through Nicole) and 2005 (Maria through Rita). There were also five consecutive hurricanes in the very active years of 1887 and 1933.
What sets 2010 apart from those other years, however, is that this year's five in a row took place in October, whereas the others were closer to the climatological "peak" of the season: 8/14-9/18 for 1887, 8/28—9/25 in 1933, 9/19—12/1 in 1998, and 9/2—9/24 in 2005. (Note that 1998's six took nearly two-and-a-half months to finish)
To summarize a key point: all five of this October's TCs became (or shortly will have become) hurricanes, and that appears to have never happened before (though I'll keep checking).
Appears Tomas is moving a little more north than expected. I still don't think the models have a good handle on him just yet. Good thing we have competent forecasters on this. (and some incompetent ones keeping them in check)
OMG I don't have my glasses on and I read your name and said to myself "self how did wunderground allow such a name like catpoop on here".
back to weather, the models may not have a good read on Tomas but the NHC has shown time & time again this season to have a good read through the first 3 days at the least.
That being said things don't bode well for Haiti but it looks like Jamaica is in better shape than it was before but all of that is still over 5 days out.
Link
Here ya geaux!
A nail biter Tomas is...
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