TD 2 forms in the Atlantic; hundreds feared dead from Typhoon Morakot; Felicia hits

By: Dr. Jeff Masters , 1:55 PM GMT on August 11, 2009

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Tropical Depression Two has formed out of the strong tropical wave off the coast of Africa we've been watching, and has a good chance of becoming the Atlantic hurricane season's first named storm. Satellite loops of the storm show that heavy thunderstorm activity is increasing near the storm's center, and low-level spiral bands are getting better established. However, dry air to TD 2's north is interfering with this process, and the storm is being slow to organize. This morning's QuikSCAT pass missed TD 2.


Figure 1. Current satellite image of TD 2.

Wind shear over the storm is low, 5 knots, and is expected to remain low to moderate, 5 - 15 knots, through Thursday. Sea Surface temperatures are a marginal 26 - 27°C, and there is plenty of dry, stable air from the Saharan Air Layer (SAL) to to TD 2's north. The relatively cool SSTs and dry air mean that TD 2 will not be able to intensify quickly. However, does appear likely that TD 2 has enough going for it that it will be able to become Tropical Storm Ana later today or on Wednesday. Most of the computer models show some weak development, but none of them predict TD 2 will become a hurricane. It is unusual for storms forming this far north to make it all the way across the Atlantic to hit the Lesser Antilles Islands, and the current NHC forecast track aiming TD 2 north of the islands appears to be a good one.

Elsewhere in the Atlantic
Two other tropical waves, one passing through the Lesser Antilles Islands, and one about 600 miles east of the islands, are mentioned in NHC's Graphical Tropical Weather Outlook. Both of these waves have very limited heavy thunderstorm activity that is not increasing, and are not a threat to develop over the next two days. None of the computer models develop either of these waves.

A large, disorganized tropical wave is just leaving the coast of Africa, south of the Cape Verdes Islands. The GFS and ECMWF models continue to predict the possible development of this wave late this week.


Figure 2. Track and total rain amount from Typhoon Morakot. Image credit: NASA/GSFC.

Death toll from Typhoon Morakot in the hundreds
The death toll from Typhoon Morakot continues climb, as a landslide triggered by the storm's heavy rains hit the small town of Shiao Lin in southern Taiwan. Shiao Lin has a population of 1,300, and 400 - 600 people are missing in the wake of the landslide. Morakot killed an additional 41 elsewhere on Taiwan, with 60 missing. Earlier, the storm killed 22 in the Philippines, and went on to kill 6 in mainland China, which it hit as a tropical storm with 50 mph winds and heavy rain. Morakot's heavy rains caused an estimated $1.3 billion in damage to China.

Morakot moved very slowly as it passed over Taiwan, dumping near world-record amounts of rain. Alishan in the mountains of southern Taiwan recorded 91.98" of rain over a two-day period, one of the heaviest two-day rains in world history. The world 2-day rainfall record is 98.42", set at Reunion Island on March 15 - 17, 1952. Alishan received an astonishing 9.04 feet of rain over a 3-day period. The highest 1-day rainfall total ever recorded on Taiwan occurred Saturday at Weiliao Mountain in Pingtung County, which recorded 1.403 meters (4.6 feet or 55 inches) or rain. Nine the ten highest one-day rainfall amounts in Taiwanese history were reached on Saturday, according to the Central Weather Bureau.

Felicia continues to weaken, but is a flash flooding threat to Hawaii
Tropical Storm Felicia continues to steadily weaken, thanks to high wind shear of 30 knots. Recent satellite loops show that almost no heavy thunderstorm activity remains, and what little there is has been pushed to the northeast side of the center, exposing the surface center as a swirl of low clouds.


Figure 3. Tropical storm Felicia appeared as a swirl of low clouds with one spot of heavy thunderstorm activity to the northeast as it approached Hawaii yesterday evening.

High wind shear will continue to weaken Felicia today, and the storm is unlikely to cause major flooding problems as it moves over the islands today. The greatest danger of flooding will be over the northern islands, where Felicia's main moisture is concentrated.

Link to follow:
Wundermap for Hawaii

Blog comments not recommended
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I'll have an update Wednesday morning.

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Quoting weathersp:


I am pleasently supprised on how willingly you ask questions.. this is what the blog is here for!

Ok here goes..

A wind barb is like a wind vane on top of a farm house roof.. The "stick" points into the wind, its the oppsite of a flag.

For wind speeds a long "barb" is 10 kts a "short barb" is 5 and a triange is 50 kts..

Here is a great website for you.. lots of learning here:

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/home.rxml

Heres the page about wind barbs:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/maps/sfcobs/wnd.rxml


Thank you, this is great info.

Quoting jeffs713:
Wow.. a TD forms, and the bickering slows down, and people actually start to help each other! Whats next? People saying "thank you" or "Please?" ;)


Just seems we have a nice bunch this evening.
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Quoting jeffs713:
Wow.. a TD forms, and the bickering slows down, and people actually start to help each other! Whats next? People saying "thank you" or "Please?" ;)


crazy talk
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AL 02 2009081200 BEST 0 148N 311W 25 1006 TD
Member Since: September 23, 2005 Posts: 15 Comments: 11341
Me say thank you?? Puhleeze =P
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It's all your fault..lol. Kiddn.
When do you think they will finally name TD2 Ana?


Well convection appears to be deepening but the numbers are wacked out right now i would have to say maybe at 11 or sometime early tomorow morning if the deep convection can persist
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Quoting truecajun:
one more question. how do you quote a post, so that it can be a reference for your response? do y'all just copy and paste?


There is a "quote" action at the bottom of each comment. It looks like this:
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duuhhhhh! i never noticed that quote button. thanks.
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Wow.. a TD forms, and the bickering slows down, and people actually start to help each other! Whats next? People saying "thank you" or "Please?" ;)
Member Since: August 3, 2008 Posts: 16 Comments: 5891
Quoting truecajun:
Ok. don't get mad at me. I know we've been through this a MILLION times - wind barbs.
I need a refresher every new hurricane season.
\__ is a westerly wind and __/ is an easterly wind.

extra slashes are 10 more knots and a half slash is 5?


I am pleasently supprised on how willingly you ask questions.. this is what the blog is here for!

Ok here goes..

A wind barb is like a wind vane on top of a farm house roof.. The "stick" points into the wind, its the oppsite of a flag.

For wind speeds a long "barb" is 10 kts a "short barb" is 5 and a triange is 50 kts..

Here is a great website for you.. lots of learning here:

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/home.rxml

Heres the page about wind barbs:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/maps/sfcobs/wnd.rxml
Member Since: Posts: Comments:
Quoting truecajun:
one more question. how do you quote a post, so that it can be a reference for your response? do y'all just copy and paste?


Just hit "quote". Sometimes you have to hit it twice to get it to work. /southwest?
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Quoting louisianaboy444:
missed naps - the WORST!

haha yeah the kid takes naps everyday and i never take naps today i took a 4 hour nap and he didn't even shut his eyes...it has been a weird backwards day....but i was also up at 5 AM on here


It's all your fault..lol. Kiddn.
When do you think they will finally name TD2 Ana?
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I have a really bad feeling this blog will be so full of bloggers screaming their heads off maybe next week if Ana or Bill forms.
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Quoting truecajun:
one more question. how do you quote a post, so that it can be a reference for your response? do y'all just cut and paste?

The "Quote" link on the bottom of each post, next to the other handy-dandy button on the blog, the "ignore user" button. (and for some reason, I have abused the latter link)

When you quote, your comment text box should start out with something like " < blockquote..."
Member Since: August 3, 2008 Posts: 16 Comments: 5891
Quoting Patrap:


Western North Atlantic
Layer Mean Wind Analyses


Thanks much!
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Quoting truecajun:
one more question. how do you quote a post, so that it can be a reference for your response? do y'all just copy and paste?


Hit the quote button under the persons comment you wish to post. You should see it in your comment box. Just write your response underneath.
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Stormsurgeon and Jeff answered. Thanks. No need for more. I should have just googled. so sorry.
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Quoting truecajun:
Ok. don't get mad at me. I know we've been through this a MILLION times - wind barbs.
I need a refresher every new hurricane season.
\__ is a westerly wind and __/ is an easterly wind.

extra slashes are 10 more knots and a half slash is 5?


Always remember, the wind direction is the direction the wind is coming FROM.
Member Since: Posts: Comments:
Quoting truecajun:
Ok. don't get mad at me. I know we've been through this a MILLION times - wind barbs.
I need a refresher every new hurricane season.
\__ is a westerly wind and __/ is an easterly wind.

extra slashes are 10 more knots and a half slash is 5?

You got it. And the flag is 50kt.
Member Since: August 3, 2008 Posts: 16 Comments: 5891
one more question. how do you quote a post, so that it can be a reference for your response? do y'all just copy and paste?
Member Since: Posts: Comments:
Quoting truecajun:
Ok. don't get mad at me. I know we've been through this a MILLION times - wind barbs.
I need a refresher every new hurricane season.
\__ is a westerly wind and __/ is an easterly wind.

extra slashes are 10 more knots and a half slash is 5?


You locked the blog up with that question.

/ west.......\ east
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missed naps - the WORST!
Member Since: Posts: Comments:
Ok. don't get mad at me. I know we've been through this a MILLION times - wind barbs.
I need a refresher every new hurricane season.
\__ is a westerly wind and __/ is an easterly wind.

extra slashes are 10 more knots and a half slash is 5?
Member Since: Posts: Comments:
2178. Patrap


Western North Atlantic
Layer Mean Wind Analyses
Member Since: July 3, 2005 Posts: 428 Comments: 129778
Quoting StSimonsIslandGAGuy:
Last year the ECMWF was not conservative. At all. It kept developing Typhoon Tip type storms east of the Bahamas. It was so crazy I put a T behind the F in the model :)


Yea that's true, but I was referring to this year. Never developed anything that the other models did.
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Quoting Relix:
Man.... I am now worried about future Bill. When all these models are in agreement of strength and track... there's something bound to happen. Going to watch out more for this than Ana here in Puerto Rico. Ana seems pretty much out of the woods to the Antilles... but possible Bill is seriously scaring me.


como dicen en la pista...

no te asustes... preocupate

jeje

esta es la parte emocionante de esto... no x que los modelos digan significa que ocurra...
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Quoting Stormchaser2007:
As StormW mentioned...there is a developing anticyclone over the "Bill" wave.

Sounds like something along this lines?

The existence of an upper level ridge allows upper level divergence which leads to surface convergence. If a capping mid-level ridge does not exist, this leads to free convection and the development of showers and thunderstorms if the lower atmosphere is humid. Since tropical cyclones strengthen these ridges, a positive feedback loop develops between the convective tropical cyclone and the upper level high, where the strength of both systems intensifies. This loop stops once ocean temperatures under the system cool sufficiently, under 26.5 °C (79.7 °F),[15] which forces the thunderstorm activity to wane, which then weakens the upper level ridge.

Link
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2174. WxLogic
Quoting Acemmett90:
ahh billy has some fearce winds


Well... its either Die Hard or Live Free... situation.
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2173. Patrap
Quoting KimberlyB:
Hey Patrap? Can you recommend a site(s) to me that has those Surface Wind Analysis-Wind Field graphics?


Wait one,
Member Since: July 3, 2005 Posts: 428 Comments: 129778
There's a lot of dry air out there in front of TD2. May inhibit development.....input.



Sat Image Loop East Atl.
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SouthALWX, good point. Model consensus is key.
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Quoting Acemmett90:

Keep in mind this was from an hour ago



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 11 AUG 2009 Time : 234500 UTC
Lat : 14:36:52 N Lon : 30:52:22 W


CI# /Pressure/ Vmax
3.0 /1000.0mb/ 45.0kt


Final T# Adj T# Raw T#
(3hr avg)
3.0 3.2 3.2

Latitude bias adjustment to MSLP : 0.0mb

Center Temp : 0.5C Cloud Region Temp : -22.7C

Scene Type : SHEAR (0.15^ TO DG)

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF


no way that blob of convection brought it down to 1000mb and 45 kt winds..im thinking we got a bad reading/estimate...do you believe it jumped that fast? with the way it looks?...no way possible...
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2169. Patrap
Thanks for the graphic on that situ 456..always a good idea to show that one.
Member Since: July 3, 2005 Posts: 428 Comments: 129778
Hey Patrap? Can you recommend a site(s) to me that has those Surface Wind Analysis-Wind Field graphics?
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This is why the wave behind Td 2 pose the greatest threat. There a mid-level ridge situated over the SW Atlantic

ecmwf - 168 HRS

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There are no 45Kt winds as of now.
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2162. Patrap
AL022009 - Tropical Depression 02

Time of Latest Image: 200908111935

Multiplatform Satellite Surface Wind Analysis,Wind Field
Member Since: July 3, 2005 Posts: 428 Comments: 129778
Some info on models... looking at the modeling showing 1000mb storms and thinking "oh it's a TS then?" is not bad logic however alot of times when you look at the models they are simply not hi res enough to see what the very center pressure could be. TCs generally have a very quick drop in pressure near the very center, so a circle of 1000mb may have a smaller, unshown center of 950mb or lower. just a thought.. and ECMWTF conservative? Once it has a storm I distinctly remember it blowing some apocalyptocanes up last year...
The key here is model consensus, not just that the euro shows a killer.
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Quoting Nolehead:
2067. serialteg 11:55 PM GMT on August 11, 2009
Quoting Nolehead:
2032. serialteg

lucky dog.....


i know! :D :D :D :D :D :D im as giddy as a kid thrown into a toys r us spree... i know its just models but...

can someone please link me up to the ECMWF forecasts so i can see them? since google and i have epic failed at this tonight XD


Link


I love you, man :D

Also, why are the winds in the QuickSCAT near Africa blowing towards the west? The barbs behind tell you the direction (||____ is 20knot west?) right? Is it low level?
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Quoting Acemmett90:

taht leave td 2 only 22 mph short of a cat one

Where do you get 45kt winds?
Member Since: August 3, 2008 Posts: 16 Comments: 5891
2157. srada
2138. aquak9 12:14 AM GMT on August 12, 2009
srada, you're right, sir. Or ma'am.


Ms...everyone hang in there!
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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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