Tomas significantly weaker; damage very heavy on St. Lucia and neighboring islands

By: Dr. Jeff Masters , 6:38 PM GMT on October 31, 2010

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Hurricane Tomas dealt a punishing blow to the Caribbean island of St. Lucia, with the neighboring islands of St. Vincent, Dominica, and Barbados also suffering heavy damage. St. Lucia received the full brunt of the northern eyewall of Tomas as it intensified into a Category 2 hurricane with 100 mph winds early this morning. The St. Lucia weather service reported that sustained winds of 90 - 95 mph affected the island. A state of emergency has been declared on the island, and there are island-wide power outages on both St. Lucia and Dominica. Heavy flooding affected St. Lucia, washing out many bridges, and the airport is closed due to flooding. Damage to structures is considerable, with many roofs gone, and damage reported to hospitals, schools, and businesses.


Figure 1. Torrential rains from Tomas triggered massive flooding on St. Lucia that destroyed several bridges and severely damaged roads. Image credit: Caribbean Hurricane Network.

Tomas significantly weakens
An Air Force hurricane hunter aircraft arrived at Tomas at 2pm this afternoon, and found a much weaker storm. The 2pm EDT center fix found that the pressure has risen to 994 mb, and the strongest surface winds were barely Category 1 hurricane strength, 74 mph. The aircraft found the the eyewall had mostly collapsed. Satellite loops of Tomas also show a significant degradation in the appearance of the storm in recent hours. The storm is highly asymmetric with very little heavy thunderstorm activity or upper level outflow on the west side, and the hurricane has only one prominent spiral band, on the east side. Wind shear is a high 20 knots due to strong upper level west-southwest winds, and these winds are driving dry air at mid-levels of the atmosphere into Tomas' west side, as seen on water vapor satellite imagery.


Figure 2. MODIS satellite image of Tropical Storm Tomas taken at 10:30am EDT Saturday October 30, as the storm began lashing the Lesser Antilles. At the time, Tomas was a Category 1 hurricane with 75 mph winds. Image credit: NASA.

Track forecast for Tomas
The ridge of high pressure pushing Tomas to the west-northwest will weaken by Tuesday, as a trough of low pressure approaches the eastern U.S. and breaks down the ridge. This will result in Tomas slowing from its current 9 mph forward speed to 5 mph by Tuesday. By Thursday, the trough to Tomas' north should be able to pull the storm to the north. The exact timing and location of this turn is still very uncertain. The computer model solutions from the latest set of 8am EDT (12Z) runs include a strike on Haiti on Friday (GFS and GFDL models), a strike on the Dominican Republic on Friday (NOGAPS model), a strike on Haiti on Saturday (UKMET model), a strike on Jamaica and eastern Cuba on Thursday (Canadian), or a strike on Puerto Rico on Friday (HWRF).

Intensity forecast for Tomas
Wind shear is forecast to remain in the high range, 20 - 25 knots, through Monday night, then decline to the moderate range, 10 - 20 knots, for the remainder of the week. Tomas will struggle with the shear and the dry air to its west through Tuesday, and I expect it will weaken to a tropical storm tonight, and remain a tropical storm until Tuesday, when the shear finally relents. At that point, re-intensification is likely, though with the storm's inner core gone, I expect it will take Tomas two days before it can re-establish a complete eyewall. Hindering that process will be the slow motion of the storm, which will allow cooler waters from the depths upwell to the surface and cool the SSTs. Still, the waters are very warm in the Caribbean and these waters extend to great depth, so the upwelling cool water may not impede intensification as much as might ordinarily be expected. The intensity Tomas might have as landfall in Hispaniola or Jamaica is highly uncertain, and a strength anywhere between a tropical storm and Category 3 hurricane would not be surprising. The HWRF model predicts Tomas will be a borderline tropical storm/Category 1 hurricane on Friday, while the GFDL foresees Tomas will be a strengthening Category 3 hurricane as it bears down on Haiti Friday afternoon. I predict Tomas will have trouble reorganizing, and will be a strengthening Category 1 hurricane on Friday as it makes landfall in Haiti or the Dominican Republic.


Figure 3. Hurricane specialists Robbie Berg (background) and Dan Brown (foreground) discuss the latest data on Tomas Friday night at the National Hurricane Center.

Next update
I'll have an update Monday morning.

Jeff Masters

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Quoting DoverWxwatchter:
I did not know that Victoria BC qualified as a Mediterranean climate. I thought the summers were too cold. Learned something new.

I know...I just read a whole article on Victoria....now I wanna go there.
Member Since: October 31, 2007 Posts: 2 Comments: 884
If you are driving down a road you have never been on before and you see a "curve ahead" sign, would you slow down?...If you suspected that human activity was damaging the environment....would you at least examine that activity so you could understand the repercusions?
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Quoting alfabob:
Up in Michigan the average max temperature during summer has been 5F over average, about 8F over average for the minimal temperatures (According to data taken from several sources). Pretty sure the great lakes have also had near record surface temperatures also. Don't really mind discussing GW, as long as anyone involved supplies sources or something interesting to read. Keeps pointless comments out of the forums while still educating others.

On the other hand, convection seems to be on the rise for Tomas. Intensity and steering is in the air for now, a lot of things could happen.



I'm shocked by this informative and reasonable responce.;^)
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535. WXTXN
Quoting jasoniscoolman2010xo:
high winds shear hitting this storm storm!!!

You should check out Levi's Vid for today... he explains the psudo shear
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Quoting flsky:

Can you tell me the time/date for this image. The text is too small to read.


Click "Ctrl +" on your keyboard several times to zoom in. Press "Ctrl -" to go back to the original zoom level.
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532. flsky
Quoting sunlinepr:

Can you tell me the time/date for this image. The text is too small to read.
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zzzzz
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Haiti can't catch a break. Weak or not, it's still going to rain like mad.

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Quoting EricSFL:


What was expected? The SW movement or the formation of 93L?


The S of due west. I don't know anything of 93L.
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528. xcool
freeze for the Northshore on friday and satdayy
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Quoting CyclonicVoyage:


Expected and mentioned in the NHC advisories.


What was expected? The SW movement or the formation of 93L?
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Quoting jasoniscoolman2010xo:
high winds shear hitting this storm storm!!!


The 300-400mb level is the same that plagued Richard. Shear accompanied by dry to the bone air undercutting the pretty cirrus outflow. Glad to see the NHC paying extra attention to the cross sections this time.
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Quoting jasoniscoolman2010xo:
high winds shear hitting this storm storm!!!
Hey! No CAPLOCKS!...very nice!
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Quoting Orcasystems:


We hit 100 this summer... not fun
Normally its about 24-28 during the summer... we hit 40+ a few times this summer... way to hot.
That's weird, we usually get a few 100 degree days here but we only had a few mid 90' days.((be careful....we may wake the GW debate team with this line of conversation!:^)
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Quoting 7544:
hi was this south west movement expected ? tia t

and could that be pre 93l right behind tomas ?


Expected and mentioned in the NHC advisories.
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Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting EricSFL:


The CoC is located at 14N 67W. Apparently moving due west or maybe even a little south of due west.


Thanks...
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Quoting DoverWxwatchter:
I did not know that Victoria BC qualified as a Mediterranean climate. I thought the summers were too cold. Learned something new.


We hit 100 this summer... not fun
Normally its about 24-28 during the summer... we hit 40+ a few times this summer... way to hot.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Sleepy Time...


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Recon showing steady 39mph surface winds

16.517N 65.350W
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516. 7544
hi was this south west movement expected ? tia t

and could that be pre 93l right behind tomas ?
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Quoting sunlinepr:


The CoC is located at 14N 67W. Apparently moving due west or maybe even a little south of due west.
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Quoting DoverWxwatchter:
I did not know that Victoria BC qualified as a Mediterranean climate. I thought the summers were too cold. Learned something new.
That's whats makes me put up with the trolls on this site. There are some smart, interesting folks that frequent this blog.
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Quoting sunlinepr:
Convection East of COC?? Or COC has reformed East???



Center of Thomas is moving S of due W, @ 14N 66.9W

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510. Relix
Quoting sunlinepr:
Convection East of COC?? Or COC has reformed East???



COC is evident in microwave imagery
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Quoting sunlinepr:
Convection East of COC?? Or COC has reformed East???

Die! Tomas, Die!
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Convection East of COC?? Or COC has reformed East???

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HH is feet wet
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Pocatello Precipitation Annual Precipitation (inches) 12.1
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Quoting PrivateIdaho:
You guys have crazy differences in weather due to topography.


Yup... we are one of the very few places that are actually considered to have an official "Mediterranean Climate"

Total annual precipitation is just 608 mm (23.9 in) at the Gonzales weather station in Victoria, contrasted to nearby Seattle, (137 km/85 mi away to the southeast), with 970 mm (38.2 in) of rainfall, or Vancouver, 100 km (62 mi) away, with 1,219 mm (48 in) of rainfall. Perhaps even more dramatic is the difference in rainfalls on Vancouver Island. Port Renfrew, just 80 km from Victoria on the wet southwest coast of Vancouver Island receives 3,671 mm (144.5 in). Even the Victoria Airport, 25 km (16 mi) north of the city, receives about 45 per cent more precipitation than the city proper. One of the most striking features of Victoria's climate is the distinct dry and rainy seasons. Nearly two thirds of the annual precipitation falls during the four wettest months, November to February. Precipitation in December, the wettest month (109 mm/4.3 in) is nearly eight times as high as in July, the driest month (14 mm/0.55 in). During the summer months, Victoria is the driest major city in Canada.

Victoria averages just 26 cm (10.2 in) of snow annually, or about half that of Vancouver. Every few decades, Victoria receives very large snowfalls, including the more than 100 cm (39.4 in) of snow that fell in December 1996. On the other hand, roughly one third of winters will see virtually no snow, with less than 5 cm (1.97 in) falling during the entire season. When snow does fall, it rarely lasts long on the ground. Victoria averages just 2–3 days per year with at least 5 cm (1.97 in) of snow on the ground.
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Quoting geepy86:
one tenth of a inch?
Yeah all the moisture is being shunted to the north. A tenth of an inch of rain equals 1-2 inches of snow depending on temperature.
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As of the last observation at 04:33:30Z, the plane's...

Direction of Travel: W (270°)
Location: 95 miles (154 km) to the ESE (121°) from San Juan, Puerto Rico (USA).

and they are off
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Morning All.

Didn't expect to see Thomas in this kinda shape tonight, sheesh.

Recon getting ready to take off.

04:33:30Z 17.700N 64.817W 1012.3 mb*
(~ 29.89 inHg*) - 1010.6 mb*
(~ 29.84 inHg*)
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Quoting Orcasystems:


I am on the Southern most part of the Island... we are protected by the Olympic Mountain rain shadow... and the Island Mountain Range :)
You guys have crazy differences in weather due to topography.
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It looks like the wind shear may be weakening a bit over Tomas. It also appears as if the high pressure that was over him, is building back to the west and north. At least that's what appears to be happening, in the satellite imagery.

Shear remains a problem for the foreseeable future, however.
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brrr.
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one tenth of a inch?
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coldest night of the year so far my are may go down to 25 or 26 f with chills in high teens by daybreak
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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
201 PM MDT SUN OCT 31 2010


.SHORT TERM...TONIGHT THROUGH TUES NIGHT...RAIN AND SNOW SHOWERS
OVER THE EASTERN HIGHLANDS WILL EXIT INTO WYOMING THIS AFTERNOON.
ANOTHER UPPER LEVEL SHORTWAVE TROUGH OVER SOUTHWEST IDAHO WILL
SWING THRU EASTERN IDAHO LAT THIS AFTERNOON AND EVENING...BRINGING
ANOTHER ROUND OF RAIN AND SNOW SHOWERS FOR MOST AREAS. PRECIP
AMOUNTS ARE EXPECTED TO BE ONE TENTH OF AN INCH OR LESS WITH SNOW
LEVEL REMAINING AROUND 6500 TO 7000 FEET. SNOW AMOUNTS AT HIGHER
ELEVATIONS UP TO 1 TO 2 INCHES POSSIBLE WITH THIS SYSTEM. THIS
SYSTEM WILL QUICKLY EXIT THE STATE WITH PRECIPITATION ENDING
DURING THE EARLY MORNING HOURS. HIGH PRESSURE RIDGE BUILDS IN
BEHIND THIS SYSTEM ON MONDAY BRINGING A DRYING AND WARNING TREND.
DSH

.LONG TERM...WEDNESDAY THROUGH SUNDAY...LARGE UPPER LEVEL RIDGE
WILL DOMINATE WEATHER MOST OF THE LONG TERM FORECAST PERIOD.
GENERALLY WELL ABOVE NORMAL TEMPERATURES AND VERY DRY WEDNESDAY
THROUGH FRIDAY. RIDGE PUSHES EAST SATURDAY AND HAVE FIRST CHANCE
FOR PRECIPITATION IN GRIDS ON FRIDAY NIGHT WITH A CHANCE THROUGH
SUNDAY. EUROPEAN REBUILDS RIDGE SUNDAY BUT GFS STAYS MORE ZONAL
AND BRINGS IN ANOTHER PACIFIC SYSTEM SUNDAY NIGHT. FOR NOW KEPT IN
NEAR CLIMATOLOGICAL PRECIPITATION CHANCES. GK
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Quoting SuperTyphoonLionrock:
Hola Tormentoso!

¿Como Esta Tu Madre?
she is dead two years ago! ella murio hace dos años! y la tuya como esta?
Member Since: July 30, 2010 Posts: 0 Comments: 288
Quoting KEEPEROFTHEGATE:

Warnings

Wind warning for
West Vancouver Island continued

Southeast winds of 90 to 120 km/h over the Queen Charlottes will abate near midnight.

Southeast winds of 80 to 110 km/h over coastal sections of the north and central coasts and over exposed sections of North Vancouver Island will develop early this evening.

Southeast winds of 70 to 90 km/h over west/East Vancouver Island and the Sunshine Coast will develop late this evening.

This is a warning that potentially damaging winds are expected or occurring in these regions. Monitor weather conditions..Listen for updated statements.

An intense pacific frontal system just west of the Charlottes will move to the north coast this evening. Strong southeast winds have already developed over the Queen Charlottes and will spread down the coast later this evening. Speeds ranging from 90 to 120 km/h will gradually diminish tonight and early Monday morning as the front moves inland.

Moisture associated with this system will result in rainfall amounts up to 70 mm over Howe Sound this evening through Monday afternoon.


I am on the Southern most part of the Island... we are protected by the Olympic Mountain rain shadow... and the Island Mountain Range :)
Member Since: October 1, 2007 Posts: 81 Comments: 26511
Dang, hate it when I'm right!
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Toronto Pearson Int'l Airport
Date: 12:00 AM EDT Monday 1 November 2010
Condition: Partly Cloudy
Pressure: 30.32 inches
Tendency: rising
Visibility: 15 miles
Air Quality Health Index: 2

Temperature: 30.9°F
Dewpoint: 22.1°F
Humidity: 69 %
Wind: N 6 mph
Wind Chill: 25
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Quoting PrivateIdaho:
Yeah, Orca is Doom!

Warnings

Wind warning for
West Vancouver Island continued

Southeast winds of 90 to 120 km/h over the Queen Charlottes will abate near midnight.

Southeast winds of 80 to 110 km/h over coastal sections of the north and central coasts and over exposed sections of North Vancouver Island will develop early this evening.

Southeast winds of 70 to 90 km/h over west/East Vancouver Island and the Sunshine Coast will develop late this evening.

This is a warning that potentially damaging winds are expected or occurring in these regions. Monitor weather conditions..Listen for updated statements.

An intense pacific frontal system just west of the Charlottes will move to the north coast this evening. Strong southeast winds have already developed over the Queen Charlottes and will spread down the coast later this evening. Speeds ranging from 90 to 120 km/h will gradually diminish tonight and early Monday morning as the front moves inland.

Moisture associated with this system will result in rainfall amounts up to 70 mm over Howe Sound this evening through Monday afternoon.
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Quoting pcola57:

Thanks sunlinepr, I'll work on that.."preciate it..
v/r
Moe


Enjoy it.... Anyone has any ideas or Met. links to share, I'm here to learn....
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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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