Season's first tropical depression forms

By: Dr. Jeff Masters , 3:43 PM GMT on May 28, 2009

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Nature is jumping the gun a bit this year, with the season's first tropical depression forming four days before the official start to hurricane season. The area of disturbed weather (91L) that we've been watching, about 250 miles east-northeast of Cape Hatteras, North Carolina, has developed enough heavy thunderstorm activity and spin to be classified as a tropical depression. QuikSCAT imagery from last night revealed a closed surface circulation, but top winds of only 20 - 25 mph. Satellite estimates (using a cloud pattern recognition method called the "Dvorak" technique) were saying this was a tropical depression this morning, though, so the NHC elected to upgrade the system.

The disturbance is over the relatively warm waters of the Gulf Stream (25°C) and has wind shear of 5 - 10 knots over it, and these conditions are marginally favorable for some slow development to occur until Friday, when the system will likely move over waters too cold to support intensification. TD One is not a threat to any land areas. I give the storm a 60% chance of becoming Tropical Storm Ana.


Figure 1. Latest satellite image of TD One.

Is the formation of TD One a harbinger of an active hurricane season?
Probably not. Early season storms occurring near the U.S. coast have not been shown to be correlated with an active main portion of hurricane season during August - October. However, the situation is different if we start getting June and July storms in the deep tropics between Africa and the Lesser Antilles Islands. This was the case last year, when the formation of Hurricane Bertha in the deep tropics in July presaged an active 2008 hurricane season. According to the Hurricane FAQ, "as shown in (Goldenberg 2000), if one looks only at the June-July Atlantic tropical storms and hurricanes occurring south of 22°N and east of 77°W (the eastern portion of the Main Development Region [MDR] for Atlantic hurricanes), there is a strong association with activity for the remainder of the year. According to the data from 1944-1999, total overall Atlantic activity for years that had a tropical storm or hurricane form in this region during June and July have been at least average and often times above average. So it could be said that a June/July storm in this region is pretty much a "sufficient" condition for a year to produce at least average activity."

Portlight.org offering relief to Florida flood victims
Tropical disturbance 90L dropped as much as two feet of rain over Northeastern Florida last week, causing severe flooding. In Volusia County, at least 1500 homes were damaged by the flooding, and many of these were in low-income housing projects where the residents did not have flood insurance. Portlight Strategies, Inc., is now working to assist in this area by providing durable medical equipment to the disabled, elderly, or injured that have lost equipment due to the flooding. Equipment will also be provided to local shelters and other organizations working with flood victims. To help out, visit the Portlight disaster relief blog..


Figure 2. Rainfall amounts over Florida for the two weeks ending on May 27, 2009. Images credit: NOAA.

Jeff Masters

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Is there such a thing as a recurvature or is it just a curve without a RE ? I am always confused when I hear that a storm is recurving.
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Anyone know any good schools to go to to study atmospheric sciences(mainly hurricanes).
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No posts in almost 15 minutes!

Also, now I give TD 1 a 70-90% chance of it becoming TS Ana by tommorow.
Member Since: September 21, 2008 Posts: 9 Comments: 688
Quoting cg2916:
Back on the last post, how did nrtiwlnvragn get that renaming from 91L to 01L?


The information comes from the Automated Tropical Cyclone Forecast (ATCF) database.
The description of the database is here.
Member Since: September 23, 2005 Posts: 14 Comments: 10875

Preparing for the Journey Home



Space shuttle Atlantis is shown suspended from a sling in the Mate-DeMate Device at NASA's Dryden Flight Research Center during preparations for its ferry flight back to the Kennedy Space Center in Florida. The shuttle landed at Edwards Air Force Base, concluding the 13-day STS-125 mission to service and repair the Hubble Space Telescope.

Image Credit: NASA/Tony Landis
Member Since: July 3, 2005 Posts: 420 Comments: 127546
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Quoting naplesdreamer28:
I see quite a flare up of showers in the GOM?


Associated with a cold front. Link
Member Since: July 31, 2006 Posts: 56 Comments: 8112
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I see quite a flare up of showers in the GOM?
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When it was a INVEST..it was 91L..
since its the 2nd invest,90L was the First.

When it went to TD,.its Labeled as 01L or the FIRST Atlantic Depression.

No magic there,no secret website decoder ring necessary either.
Member Since: July 3, 2005 Posts: 420 Comments: 127546
I think I see the blob you are referring to. The one by Mexico?
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TD-1 IR loop
Member Since: July 3, 2005 Posts: 420 Comments: 127546
Quoting nocaneindy:


It went from invest 91l t.d. 01

What website, though?
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Quoting SomeRandomTexan:


Yes, there was a lot of lightning, I am also very sorry to hear about your house. I know how rough that can be :( ... Also inland counties are just as much at risk due to more wooded areas and tornados. We evacuated to Toledo Bend for Rita and learned that was a Colassal mistake, trees were downed everywhere crushing my aunts brand new Lincoln.


Thank you about the house. It was an experience. Sounds like you went thru more of the storm itself though. We were in Kilgore nearly in Dallas. Took us 19 hours to get there. LOL. But I'm glad we went. And yes the inland counties were devestated by the winds. And they were without power for weeks. And aid was longer getting to those areas as well.
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91L is a INVEST Designation.

01L is a TD designation.
Member Since: July 3, 2005 Posts: 420 Comments: 127546
Quoting sammywammybamy:
What the Heck.. there's a blob over florida?!????!?!?!?!? ... is the center of this blob off ft.myers?


Ummm....its the afternoon T-storms that we've been getting everyday this week.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
The Ts would certainly indicate TD-1s almost Ana. An explosion of convection would cause Ana to be named. Remember Marco from last year? Well TD-1 is atleast one of the top 5 smallest systems I've ever seen. This has a tight circulation and it wouldn't surprise me that this might be at TS strength already. We'd need a recon though. Also TD-1's flaring from the north.
Member Since: July 8, 2005 Posts: 259 Comments: 23568
The creepy sounds of Ike.
TWC in a blacked out Hotel in Galveston. As the eyewall passed through the building.

Link

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286. SRQfl
Quoting cg2916:
Back on the last post, how did nrtiwlnvragn get that renaming from 91L to 01L?

I was wondering how that process goes myself...invest 91L to Depression 01L
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Quoting homelesswanderer:


That is true. From what I could see after the transformers blew. But that did answer the question about whether or not there is lightning in a hurricane. There was a lot in Humberto.


Yes, there was a lot of lightning, I am also very sorry to hear about your house. I know how rough that can be :( ... Also inland counties are just as much at risk due to more wooded areas and tornados. We evacuated to Toledo Bend for Rita and learned that was a Colassal mistake, trees were downed everywhere crushing my aunts brand new Lincoln.
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Lightning in hurricane Felix- Link
Member Since: July 31, 2006 Posts: 56 Comments: 8112
Quoting cg2916:
Back on the last post, how did nrtiwlnvragn get that renaming from 91L to 01L?


It went from invest 91l t.d. 01
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A magnitude 7.1 earthquake struck offshore Honduras this morning. Shaking reported in Honduras, Guatemala, Belize, Mexico, El Salvador, Nicaragua, and Cuba. At least 5 people are killed, although the death toll is expected to rise much higher.
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Quoting SomeRandomTexan:


Well, I'm not saying that at times I wasn't scared...lol because then I would be lying, but Just watching the pure brutality of the storm was awesome...


That is true. From what I could see after the transformers blew. But that did answer the question about whether or not there is lightning in a hurricane. There was a lot in Humberto.
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Quoting homelesswanderer:


LOL. Two completely opposite views.


Well, I'm not saying that at times I wasn't scared...lol because then I would be lying, but Just watching the pure brutality of the storm was awesome...
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Back on the last post, how did nrtiwlnvragn get that renaming from 91L to 01L?
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Quoting SomeRandomTexan:


having experienced Humberto, with big pine trees snapping, it leaves you with a new respect. Likewise, I can only imagine those who stayed for Rita. That pretty much left my area over in Orange leveled.
Yeah She and the trees took my house. So after seeing that destruction guess why I'm a lil jumpy. I did live north of Vidor almost on the Jasper county line then. Thats why I always tell people inland to evacuate.
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DDR,

the activity across Africa is being caused by a variety of factors, but ITCZ instability and AEJ seems to the main caused. There does not seem to be wave-like feature at the moment but because the convection is being generated along the AEJ, I would not rule out the formation of one. The is a good amound of vorticity along West Africa but it maybe associated with a secondary circulation. Upper air observastions not showing much cyclonic turning, but any bulge in the low level moisture field over the Atlantic ocean over the next few days would signify one has/had emerge/emerged.
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Quoting DDR:
Could someone please post a map showing the current atlantic itzc position


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Quoting SomeRandomTexan:
HUMBERTO was one for the record books....lol! it was still strenghting over land... crazy storm... It was fun to sit outside and watch though


LOL. Two completely opposite views.
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Quoting homelesswanderer:


Now I'm having a flashback to Humberto. That was before I started monitoring the tropics. ( that started last year after Edouard, when I finally decided another one would never sneek up on me again.) I never want to go thru another hurricane again either. Especially in the middle of the night. And they always seem to hit here in the darkest hours. Just to add to the creepy and helpless factor. I cant imagine what people who stayed for Rita and Ike went thru. But even with a cat 1 its scary hearing it, feeling the trees come down, hoping they don't come thru the house. One thing for sure...Once they start there is nothing you can do to stop it.


having experienced Humberto, with big pine trees snapping, it leaves you with a new respect. Likewise, I can only imagine those who stayed for Rita. That pretty much left my area over in Orange leveled.
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P-H-I-S-H



Tiny TD-1

Member Since: July 3, 2005 Posts: 420 Comments: 127546
01L might not look that great right now, but remember what happened last night? Don't be surprised if this thing makes one last attempt at Ana.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
Well, this is pretty satisfying for all those who want an active season but don't want to hurt anyone. An early start to the season in which a storm forms that has a very very very small possibility of hurting someone.
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OMG, TD one already! Double OMG, NHC predicts a TS! Triple OMG, some models are predicting a southward recurvature around the Bermuda High!
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Back on the last post, how did nrtiwlnvragn get that renaming from 91L to 01L?
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TD-1 Heading out into the Open Atlantic

Enhanced IR Loop
Member Since: July 3, 2005 Posts: 420 Comments: 127546
Quoting DDR:
Could someone please post a map showing the current atlantic itzc position


I'm looking into the area you asked but it does not look so

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Quoting cg2916:
RANDOM FLASHBACK TIME... Barry '07. I went thorugh it on my vacation as an extratropical storm. Let me say one thing... if that was an extratropical storm, then I don't want to go through a hurricane.


Now I'm having a flashback to Humberto. That was before I started monitoring the tropics. ( that started last year after Edouard, when I finally decided another one would never sneek up on me again.) I never want to go thru another hurricane again either. Especially in the middle of the night. And they always seem to hit here in the darkest hours. Just to add to the creepy and helpless factor. I cant imagine what people who stayed for Rita and Ike went thru. But even with a cat 1 its scary hearing it, feeling the trees come down, hoping they don't come thru the house. One thing for sure...Once they start there is nothing you can do to stop it.
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If we want to have an active hurricane season... have Jeff Masters leave at least twice a month. Every time he leaves, something forms.
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personally i would keep this TD1. My first point is it is not that strong and that it won't effect any land areas. It would be a waste of a name in my opinion by the NHC. This is also one of the reasons why i don't believe that the number of storms have increased drastically the last 15 years during climate change. it is possible between 1930-1950 there were plenty of storms like our TD 1 that would never be classified

I personally don't think it should be named
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proximity to land causes posts
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Quoting charlottefl:
All you have to do is take a look at the 2004 season. It was a neutral season slightly in the warm phase. El Nino didn't kick in until towards the end of the season. Didn't matter much at that point. I personally think neutral conditions are more conducive to more storms IMO. Look at 2005.


I'm off for the day but my current concern is where the A-B High ultimately settles in for the Summer....Right now, it is in a position favoring, so to speak, steering into the Caribbean and East Coast of the US, which is more at greater risk of a potential landfall during an Enso neutral year......Then again, this may be the last series of fronts for now and high pressure, and heat, is going to start to settle back in over the SE US over the next several weeks and the high pressure may start building back eastwards....My point is that ENSO neutral conditions will probably result in one or two hits on the Caribbean and/or Florida/East Coast this year at some point during the season......The actual total number of storms or intensity is anyones's guess..
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260. DDR
Could someone please post a map showing the current atlantic itzc position
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maybe there speechless cause a lot said it had no chance

but everything has a chance its not an exact science we really have no clue when it comes to tropical weather just a shot in the dark NHC will admit this if asked we have some ideas but nothing solid its and ongoing study every time something forms
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Quoting Drakoen:
Almost to tropical storm strength:

CI# /Pressure/ Vmax
2.4 /1005.8mb/ 34.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.4 2.3 3.0


I've been watching it too. I have an idea... if you think TD1 will be Ana say "Ana", if you think it will stay TD1 say "TD1".
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Storm Relative 1km Geostationary Visible Imagery

Time of Latest Image: 200905282132


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256. DDR
Good evening,a question for 456 or anyone,is this feature an AEW or just itzc?
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254. IKE
Quoting hurricanemaniac123:
This is kind of funny. We had 90L which was only an invest and there was 1000+ posts on this blog. And right now there's a TD that might became TS Ana and there's less than 300 posts on this blog!


Because it was affecting a land mass...this TD is only affecting a fish mass.
Member Since: June 9, 2005 Posts: 23 Comments: 37858

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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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