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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Off to work now.

Have a good day everybody.
Member Since: Posts: Comments:
Quoting Stormchaser2007:
This should take about another 24-48 hours to organize. Definitely one of the larger AEWs I have seen.



In what latitud is the low forming?
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3354. IKE
Long-term discussion from Raleigh,NC....

"LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
-- Changed Discussion --
AS OF 425 AM TUESDAY...

WHILE THE MEDIUM RANGE NUMERICAL MODELS REMAIN IN GOOD AGREEMENT
THAT THE SUBTROPICAL RIDGE WILL DEVELOP WESTWARD INTO THE INTERIOR
SOUTHEASTERN US THROUGH EARLY-MID NEXT WEEK... THERE ARE DIFFERENCES
IN THE EVOLUTION OF THE MERGER OF AN UPSTREAM TROUGH ALOFT WITH THE
FORMER THAT WILL PLAGUE THE CAROLINAS DURING THE NEAR/SHORT TERM
PORTION OF THE FORECAST. WILL MAINTAIN CONTINUITY FROM THE PREVIOUS
FORECASTS -- BEST DEPICTED BY THE MORE CONSISTENT ECMWF -- WITH THE
EXPECTATION THAT AT LEAST ONE DMC-FOCUSING S/W-THERMAL TROUGH ALOFT
(EMBEDDED IN THE PROGRESSIVE NORTHERN PORTION OF THE TROUGH AXIS)
WILL CROSS THE MID ATLANTIC REGION SUNDAY OR MONDAY... THEN POSSIBLY
LINGER ALONG THE NC COAST INTO MID WEEK. THUS... WILL MAINTAIN
SLIGHT TO LOW CHANCE POP THROUGH THE PERIOD... HIGHEST EACH
AFTERNOON/EVENING... AND IN THE EASTERN CWA BY MON-TUE (IN CLOSER
PROXIMITY TO THE COLD POOL ALOFT). TEMPERATURES SHOULD INITIALLY
AVERAGE RIGHT AROUND CLIMO FOR MID AUGUST WITH VARIABLY TO MOSTLY
CLOUDY SKIES. A GRADUAL WARMING/CLEARING TREND EXPECTED TO NEAR OR
ABOVE 90 DEGREES BY TUESDAY... AS THE TROUGH AXIS SHIFTS AWAY FROM
THE COAST AND THE SUBTROPICAL RIDGE BECOMES INCREASINGLY DOMINANT.
-- End Changed Discussion --"

Member Since: June 9, 2005 Posts: 23 Comments: 37858
3353. WxLogic
Quoting Cotillion:
Morning Storm!

And query to anyone... for those who have been in say, both - what are the differences in being in a strong Nor'Easter and a hurricane? If there are any.


In my opinion... the only major difference would be the distance they affect a given area. Nor`Eastern are larger in scale than Hurricanes as the latter are more localized disturbances.

Of course as you know you have the core structure in which one is cold and the other one warm and so forth...

At a high level that's my take on it.
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3352. IKE
Quoting homelesswanderer:


Good morning Ike, all. I've had my full nap sleep. Lol. Does anyone think the CMC Rita jr scenario will play out? Or are they overdoing it?


Odds are their overdoing it.


Member Since: June 9, 2005 Posts: 23 Comments: 37858
Interesting setup for Anna. Could possibly
threaten south florida in 10 days or so.
The GFS is taking it thru the Islands and
then slightly North as a very strong storm.

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Quoting Samantha550:


Is that for the wave closest to the Gulf? The one no one here is really talking about?


I think its the one still east of the Carribean.
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Quoting bajelayman2:


Noted. At 35W, I am at 59.4W. Thus, 59.4-35 = 14.6 times roughly 60miles = 876 miles to travel

Moving at say, 15 mph (guess), gives it (the centre) between 50 and 55 hours to get in this area.

That means that the overall system will begin affecting the area in roughly 2 days, which is Thursday.

Bye, I am off, have a good day.


That is why we dont do things first thing am.

Was thinking today was Tuesday, till I looked at my watch while out running.

Ha. Makes it to the islands on Friday, then.
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3348. WxLogic
Quoting StormW:
Recent satellite loop imagery from EUMETSAT indicates the wave near the African coast is becoming slowly better organized.


No kidding... it is wasting no time it taking full advantage of the environment around it.
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Quoting IKE:


ECMWF does.


Me no likie.....
morning all. So, 3 yellow circles and a red X. Who has the crayons???? lol
Member Since: September 5, 2007 Posts: 0 Comments: 3488
The 00z gfdl showed something trying to form headed nw n the gom

http://moe.met.fsu.edu/cgi-bin/gfdltc2.cgi?time=2009081200-two02l&field=Sea+Level+Pressure&hour=Ani mation
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Morning Storm!

And query to anyone... for those who have been in say, both - what are the differences in being in a strong Nor'Easter and a hurricane? If there are any.
Member Since: Posts: Comments:
Quoting homelesswanderer:


Good morning Ike, all. I've had my full nap sleep. Lol. Does anyone think the CMC Rita jr scenario will play out? Or are they overdoing it?


Is that for the wave closest to the Gulf? The one no one here is really talking about?
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Quoting StormW:


I just did some quick satellite loop analysis...what we are seeing, is the convection being slightly displaced by the upper level flow. The COC is just to the east, right on the edge of the convection. The actual LLC is stil moving west. That would coincide with the 14.6N on the 5:00 a.m. update. It's the same as yesterday eve.


Thanks.
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Quoting IKE:


ECMWF does.


Good morning Ike, all. I've had my full nap sleep. Lol. Does anyone think the CMC Rita jr scenario will play out? Or are they overdoing it?
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Atlantic is hopping now!
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It's hoppin' now!

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3338. WxLogic
Quoting futuremet:


Yes.

I personally don't think these trough will be as strong as expected. Watch out for that second one, for it might be that one that drives billy into the U.S.


Indeed... GFS needs to be smoothed out a bit.
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SAL looks to be significantly less dense than a few days ago.

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Um...err..456

Member Since: July 19, 2008 Posts: 43 Comments: 4051
3335. IKE
Quoting tarpontexas:
It appears that the Canadian model is taking the wave E of the Antilles into the GOM next week. For what it is worth, it shows a landfall on upper TX to LA coast. That is the only model I have seen that does this.


ECMWF does.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Stormchaser2007:
ADT doesnt think 02L looks impressive.

Final T# Adj T# Raw T#
(3hr avg)
2.9 2.6 2.4

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +19.1C Cloud Region Temp : -5.7C

Scene Type : SHEAR (0.47^ TO DG)

Positioning Method : FORECAST INTERPOLATION

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

Tno/CI Rules : Constraint Limits : 0.5T/hour
Weakening Flag : ON
Rapid Dissipation Flag : FLAG



rofl. It had it at 3.3 last night, and it looks better organized than last night. Its either out of wack or just going back to what it should.
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3333. WxLogic
Quoting futuremet:


Another trough is expected to form out of no where along the eastern seaboard by sunday, and than pull Ana out to sea.

500MB

200MB....more apparent


I doubt it will sharpen it that quick without any other enhancing factors... should be good to take a blend of the ECMWF and GFS... ECMWF is not that aggressive with the trough development.
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Good Morning.

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It appears that the Canadian model is taking the wave E of the Antilles into the GOM next week. For what it is worth, it shows a landfall on upper TX to LA coast. That is the only model I have seen that does this.
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Quoting WxLogic:
06Z GFS is trying to make this a repeat of 04.


Yes.

I personally don't think these trough will be as strong as expected. Watch out for that second one, for it might be that one that drives billy into the U.S.
Member Since: July 19, 2008 Posts: 43 Comments: 4051
3329. WxLogic
06Z GFS is trying to make this a repeat of 04.
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Quoting IKE:


Can you explain the 2nd sentence? Not understanding you?


Another trough is expected to form out of no where along the eastern seaboard by sunday, and than pull Ana out to sea.

500MB

200MB....more apparent
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Quoting Claudette1234:


Hello 456,

Do you think TD2 can reach antilles?



not impossible, but not likely right now. If it continues to trend the way it has over the next day or 2 in could.
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I did a quick update and have TD2 heading toward the Northern Islands
Member Since: September 2, 2007 Posts: 178 Comments: 20443
3325. WxLogic
Quoting Weather456:
TD 2 also moved slightly south of due west over the past 12 hrs. Some indications of what the wave behind will be experiencing.


Well... if you notice SAT and Steering maps... you'll notice the position of the Azores High is almost oriented Sw to NE which would explain the SW jog
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Quoting Weather456:
TD 2 also moved slightly south of due west over the past 12 hrs. Some indications of what the wave behind will be experiencing.


Hello 456,

Do you think TD2 can reach antilles?
Member Since: Posts: Comments:
ADT doesnt think 02L looks impressive.

Final T# Adj T# Raw T#
(3hr avg)
2.9 2.6 2.4

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +19.1C Cloud Region Temp : -5.7C

Scene Type : SHEAR (0.47^ TO DG)

Positioning Method : FORECAST INTERPOLATION

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

Tno/CI Rules : Constraint Limits : 0.5T/hour
Weakening Flag : ON
Rapid Dissipation Flag : FLAG

Member Since: June 9, 2007 Posts: 4 Comments: 15921
3322. IKE
Quoting futuremet:


Yes, that is the Bill-trough,and it should not have any effect on Ana. The Anaian the trough is weaker.


Can you explain the 2nd sentence? Not understanding you?
Member Since: June 9, 2005 Posts: 23 Comments: 37858
3321. WxLogic
Ouch... "B" path as per ECMWF is definitely not good for the Greater Antilles...
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TD 2 also moved slightly south of due west over the past 12 hrs. Some indications of what the wave behind will be experiencing.
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Morning all,

looks like TD2 stay quiet.
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Quoting Weather456:


seems right on track

Here's the 0600Z intial conditions...notice where the low pressure area is.



Alright thanks.
Member Since: June 9, 2007 Posts: 4 Comments: 15921
3317. WxLogic
TD#2 is looking good...
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Quoting IKE:
Good morning to all.

Prognostic discussion from yesterday talked about a strong trough in the eastern USA in the 8-14 day extended.

That trough holds the key to where this goes, assuming "this" forms, which seems very likely.


Yes, that is the Bill-trough,and it should not have any effect on Ana. The Anaian the trough is weaker.
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Becuz the models predicted a disturbance would be along the coast 2day, it is likely they will be right about development and TD 3 seems likely later this week.
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3314. WxLogic
Good Morning...
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3313. IKE
Quoting futuremet:


The GFS does that for two reasons; it expects the positively tilted shortwave somewhat embedded into the ridge to amplify further and drag Ana out to sea. The GFS also somewhat expects Ana to be a little stronger in this run. This enhances the weakness in the region, and Bill moves farther North. Now, this should cause only a minor northern shift on Bill's track; a longwave trough is what will recurve Bill. The problem is: the GFS and the models have been very inconsistent regarding the exact time of this trough, and how strong it will be. This is quite a complicated set up...



Sometimes the GFS overdoes troughs. I remember it had a trough out in the Atlantic 1-2 weeks ago. A significant one. When it got closer to the time it materialized, it wasn't as significant.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
The 55W wave will inevitably refire today, and it should maintain the convection as it crosses the Caribbean.
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Quoting Stormchaser2007:


Does it seem a bit north of what the GFS is showing?


seems right on track

Here's the 0600Z intial conditions...notice where the low pressure area is.

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Quoting Weather456:


I give it 48 hrs. One thing i notice is that the system is large so it would probably take some time to organize.


Does it seem a bit north of what the GFS is showing?
Member Since: June 9, 2007 Posts: 4 Comments: 15921
Quoting IKE:
6Z GFS sends it up the east coast....trough dropping into the SE USA in about 11 days....



The GFS does that for two reasons; it expects the positively tilted shortwave somewhat embedded into the ridge to amplify further and drag Ana out to sea. The GFS also somewhat expects Ana to be a little stronger in this run. This enhances the weakness in the region, and Bill moves farther North. Now, this should cause only a minor northern shift on Bill's track; a longwave trough is what will recurve Bill. The problem is: the GFS and the models have been very inconsistent regarding the exact time of this trough, and how strong it will be. This is quite a complicated set up...
Member Since: July 19, 2008 Posts: 43 Comments: 4051
Quoting Stormchaser2007:


456 when do you think the AEW should begin organizing? How long should it take?


I give it 48 hrs. One thing i notice is that the system is large so it would probably take some time to organize.
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3306. IKE
00Z ECMWF at 10 days had it heading more WNW toward south Florida....don't really see as much of a trough on this map compared to the latest GFS>>>>>

Member Since: June 9, 2005 Posts: 23 Comments: 37858

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.