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

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I'll have an update Wednesday morning.

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1406. Patrap
C Atlantic IR loop





Member Since: July 3, 2005 Posts: 423 Comments: 127807
Quoting Weather456:
12Z GFDL also show a strong system SW of TD 2 in 126 hrs





What is that on the west coast of Florida?
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Quoting nrtiwlnvragn:
1379. atmoaggie

They just sent the message out at 1:36 PM EST.

Maybe they don't hit the whole distribution list at once...I didn't yet get that message.
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Quoting WXHEAD:
Here is a quote from a couple of years ago:
957. ustropics 9:10 AM GMT on July 05, 2007
Probably, RL3AO. I don't like when we say it "will" though. There are no wills with weather! It usually does what it wants. 96L is doing what it wants, which is teasing the crap out of us.


The flare up of convection seen during the early morning hours is known as diurnal maximum. I researched this back in 2005 and although information is rather vague and multiple reasons are given I will try to explain it best I can.

During the night the atmospheric profile is moist due to the lack of daytime heating. The temperatures over the tropics fall to the dew point. Given the sufficient forcing for rising motions and the now more moist atmospheric profile convection is expected to be at its maximum right before the sunrise (normally around 2am you can see flare ups of convection). It also helps that SSTs are at a maximum temp for the day as well.

The reason you see 96L lose its convection as the day progresses is the loss of this moist environment and the impeding inhibitor of dry air being entrained into the center of circulation, which warms up the cloud tops, killing the convection.






To sum that up, the air temps at night are cooler than the water temp. The differential is at it's extreem in the moments before sunrise.
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TD2

AOI
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12Z GFDL also show a strong system SE of TD 2 in 126 hrs



Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Stormchaser2007:
12z GFS shows the "Bill" wave at 144 hours with 86KNOT winds. What we were seeing later in the run was probably higher than a Category 3. Unfortunately it doesn't go past this.

Larger image:


I just had one of those feelings... that even though you live for meteorology and how awesome these storms are. You know that it will likely kill someone along the way if it hits land or gets close to land and some poor soul fishing 200 miles out is going to get whacked. It's a rough feeling.
Member Since: January 14, 2007 Posts: 17 Comments: 4140
Advisory on Td 2 will be out within the hour
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Quoting MsBlanch:


Has there been an issue with links that I missed?


Read Dr. M's last paragraph.
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Synopsis of the "Bill" Wave
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Quoting MsBlanch:


Has there been an issue with links that I missed?
yes see Dr Masters blog entry towards the end :)
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Quoting Seflhurricane:
dont even mention a storm to head for the gulf Gas prices are High Enough and the gulf coast is still busted up


True, but we are makin a comeback! lol
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The last several nights there's been big time flare ups of convection during diurnal max with the newly formed TD#2. I fully expect this to occur once again tonight and the end result being TD#2 becoming Ana.
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Quoting CycloneOz:
IMPORTANT ANNOUNCEMENT:

The GoM is no longer closed to TC activity.

WARNING!

The GoM is no longer closed to TC activity!!!
dont even mention a storm to head for the gulf Gas prices are High Enough and the gulf coast is still busted up
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I remember 96L from 2007, never really did have a chance but it looked great.
Member Since: July 8, 2005 Posts: 259 Comments: 23882
Quoting Chicklit:
I'm afraid to click on links in here right now. Did you get your 'puter fixed Drakoen?


Has there been an issue with links that I missed?
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Tropics becoming active
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1379. atmoaggie

They just sent the message out at 1:36 PM EST.
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IMPORTANT ANNOUNCEMENT:

The GoM is no longer closed to TC activity.

WARNING!

The GoM is no longer closed to TC activity!!!
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Quoting Weather456:
Also in that run Td 2 reappears east of the Bahamas.
thats intresting ????
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Working up a storm...
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how are the steering currents looking for next week for TD 2
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Also in that run Td 2 reappears east of the Bahamas.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting nrtiwlnvragn:
1339. atmoaggie

They moved the implementation date up, see #1245.

Hey, thanks. Wonder why I didn't get that message. (y'all pay attention when nrt posts this stuff...always on top of it)

WhyTH are they doing this in season? Of course there is no perfect time, but I would rather they put it off than move it up. Need to give Tolman a call...
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Quoting CybrTeddy:


Cant be all that ridiculous, other model's are also saying the same thing. ;)


I think he means in terms of its strength lol...
Member Since: August 2, 2007 Posts: 19 Comments: 19234
TD 2 will most likely remain at 30MPH Convection is not that impressive and the system is disorganized i think we will se TS ANA Tomorrow Morning if it gets a good DMAX like some have stated
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12z GFS shows the "Bill" wave at 144 hours with 86KNOT winds. What we were seeing later in the run was probably higher than a Category 3. Unfortunately it doesn't go past this.

Larger image:
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Quoting CybrTeddy:


Cant be all that ridiculous, other model's are also saying the same thing. ;)


ridiculous in the sense of how intense it is. And that's not the only model that shows it.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Stormchaser2007:


Well the 18z is important to me becuase I need to know how the "extra" energy will play a role in this waves potential development.

I tend to stray away from 18z runs, since they don't have a drastically different or new data set to work with, and some of their upper-air data may be 18 hours old. I put a lot more faith in the 00z runs.
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1373. WxLogic
Quoting Weather456:
Ridiculous storm in 1 week



Like Zoolander would say... Ridiculously good looking... of course not once it touches land.
Member Since: August 14, 2008 Posts: 4 Comments: 4965
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Quoting CaneWarning:


That's got to have you concerned...


vigilant
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:
Ridiculous storm in 1 week



Cant be all that ridiculous, other model's are also saying the same thing. ;)
Member Since: July 8, 2005 Posts: 259 Comments: 23882
Quoting HadesGodWyvern:
CPHC TC Guidance is going back and forth with 35-40 knots for Maka


I'd say hold it at 35kt. ADT may be higher than that but the intensity estimates are largely 30-35kts.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting Weather456:
Ridiculous storm in 1 week



That's got to have you concerned...
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Quoting Stormchaser2007:


Well you have to take into account that the satellite presentation is poor so they'll likely go with 30knots at 5.


May even stay 25kts if they ignore the ADT.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Ridiculous storm in 1 week

Member Since: July 24, 2005 Posts: 407 Comments: 19076
1365. HadesGodWyvern (Mod)
CPHC TC Guidance is going back and forth with 35-40 knots for Maka
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Quoting Weather456:
5 days



Similar to what the GFS is showing.
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Quoting WxLogic:


Hope you're not interpreting the 35KTS as 35MPH... :)


I'm not, but the NHC will most likely be the typical conservative call and say 35 MPH.
Member Since: July 8, 2005 Posts: 259 Comments: 23882
@1339, that's pretty funny...it's Ed Lorenz' weather computer re-done for 2009...
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I think the NHC will average out the estimates and bump up the winds speeds to 35mph

No Ana yet
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Quoting Acemmett90:
yah that was not cool that was a low blow for us in south florida


A double - no, triple entendre!
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1339. atmoaggie

They moved the implementation date up, see #1245.
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Quoting WxLogic:


Hope you're not interpreting the 35KTS as 35MPH... :)


Well you have to take into account that the satellite presentation is poor so they'll likely go with 30knots at 5.
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1357. HadesGodWyvern (Mod)
NHC Tropical Cyclone Guidance still states 25 knots
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5 days

Member Since: July 24, 2005 Posts: 407 Comments: 19076

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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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