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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Quoting KEEPEROFTHEGATE:
well sorry stormw but i have to disagree with your claim to be honest no one not even those that think they know can predict what is to happen we can assume we can hope but the cane season will be whatever its going to be and no one can predict how it will turn out no one we casn all see what things are pointing too but i remember in 05 when the same thing was said and we all know how that turned out

my only advice be prepare better safe then sorry

While no one can say for sure what is going to happen, we can look at indicators and predict what will probably happen. Such indicators as lower SST's, neutral-El Nino conditions, and likely higher shear values in the MDR all indicate that this year will be an average to slightly below average hurricane season. With that said, all it takes is one!
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Quoting Levi32:


The GFS actually shows that happening in the last 2 runs that I've looked at. I think the reason why is because TD 1 is thrown out way in front of the upper trough over the eastern US, and is kinda stuck on the nose of the ridge between that trough and another trough in the NE Atlantic. The GFS forecasts TD 1 to continue to stay under the nose of the ridge, and as it makes its way eastward the southeasterly flow on the SW flank of the NE Atlantic trough will start to influence it, pulling it southward. This would wind up getting it stuck out in the middle of the Atlantic as a very weak feature.

However, the system will likely be almost if not already completely dissipated by the time this happens, and even if it survives the environment would be pretty hostile so re-development here is unlikely.


Thanks Levi! Would be a very interesting track...
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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.


Great information Dr.; we just have to wait and see, forget numbers predictions except as a general proposition based upon present conditions based climatology, and it will either be an average season or above average season based upon a reasonably certain ENSO neutral season.....
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Quoting StormW:


None.


StormW, you are verbose today aren't you?
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting KEEPEROFTHEGATE:
well sorry stormw but i have to disagree with your claim to be honest no one not even those that think they know can predict what is to happen we can assume we can hope but the cane season will be whatever its going to be and no one can predict how it will turn out no one we casn all see what things are pointing too but i remember in 05 when the same thing was said and we all know how that turned out

my only advice be prepare better safe then sorry


True, but if you said the same thing about one single hurricane, would that make any sense? It's our job to look for the most likely outcome and make a prediction based on what we know. It won't always come true, but that's how we learn.
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Wow, that first line of storms heading for SWFL really died out fast.
Member Since: May 15, 2009 Posts: 0 Comments: 33
well sorry stormw but i have to disagree with your claim to be honest no one not even those that think they know can predict what is to happen we can assume we can hope but the cane season will be whatever its going to be and no one can predict how it will turn out no one we casn all see what things are pointing too but i remember in 05 when the same thing was said and we all know how that turned out

my only advice be prepare better safe then sorry
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Quoting LightningCharmer:
Thank you for the update. Looks like Florida is in for more rain.

NOAA Radar

SFWMD Radar


Great more rain. I wouldnt mind just one day of full sunshine. Im tired of the flooding!
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Quoting BaltOCane:
Some of the computer models suggest that this could swing back around again later...

What are the (remote) chances of this sort of thing happening?


The GFS actually shows that happening in the last 2 runs that I've looked at. I think the reason why is because TD 1 is thrown out way in front of the upper trough over the eastern US, and is kinda stuck on the nose of the ridge between that trough and another trough in the NE Atlantic. The GFS forecasts TD 1 to continue to stay under the nose of the ridge, and as it makes its way eastward the southeasterly flow on the SW flank of the NE Atlantic trough will start to influence it, pulling it southward. This would wind up getting it stuck out in the middle of the Atlantic as a very weak feature.

However, the system will likely be almost if not already completely dissipated by the time this happens, and even if it survives the environment would be pretty hostile so re-development here is unlikely.
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Storm W, the NHC, Dr Gray & others have predicted bad, awful active hurricane seasons over the past few years. Sometimes they were right & sometimes they were not. Even though there is nothing out there to suggest that the season will be above average, you never know.

What are your predictions for the number of named storms, hurricanes, & intense hurricanes?
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Hey StormW,
What kind of chance do you give TD one looping around the Burmuda High and taking another swipe at us?
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40. IKE
Who says the Atlantic season shouldn't begin May 15th?

TD1 is born!
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Quoting Levi32:


It should track eastward over the gulf. There is next to no chance of it developing into a tropical system. There is 60 knots of shear over it and the rest of the gulf is just as hostile. It could turn into another MCC like the blob last night, but it isn't a threat except for more heavy rainfall for some people.


Good deal, thanks...
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Quoting nolajet:


Hey Storm, that was a pretty definitive answer. Sorry to take up blog space for this, but I must have missed something along the way that showed we would have a weak season? I'm all for that, just curious where I could read more. :)


http://hurricane.atmos.colostate.edu/Forecasts/

Not necessarily weak, but at least not active. Looks to be average.
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good day all i see we are off and running with 3 days left in the pre-season

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Some of the computer models suggest that this could swing back around again later...

What are the (remote) chances of this sort of thing happening?
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Quoting StormW:


No.


Hey Storm, that was a pretty definitive answer. Sorry to take up blog space for this, but I must have missed something along the way that showed we would have a weak season? I'm all for that, just curious where I could read more. :)
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Quoting Gulfsyed:
What are the chances that the surface low coming off of TX develops into a strong storm...anyone have a good idea on the track of this low. Thanks!


It should track eastward over the gulf. There is next to no chance of it developing into a tropical system. There is 60 knots of shear over it and the rest of the gulf is just as hostile. It could turn into another MCC like the blob last night, but it isn't a threat except possibly for more heavy rainfall for some people.
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What are the chances that the surface low coming off of TX develops into a strong storm...anyone have a good idea on the track of this low. Thanks!
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Should be an interesting afternoon in the severe WX department for SFL with the surface trough approaching.
Quoting TheCaneWhisperer:


You should call GM with that technology, lol, maybe they can push the 40 mile barrier.


All they need do is design a car that can operate on 30 watts! ;)

I really like this new Dell Mini-9. No moving parts, no fan...keyboard is cramped, but PenscolaDoug and I use GoToMyPC.com to interface with the unit.

Viva La Statione!
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Quoting CycloneOz:
The XtremeHurricanes.com live webcam / remote hurricane weather station is now in its 30th hour of continuous operation on batteries.

Viva La Statione! :)


You should call GM with that technology, lol, maybe they can push the 40 mile barrier.
NASA High-Resolution Visible Loop of TD 1
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Quoting Ossqss:




KEEPEROFTHEGATE 5-28
Caneaddict 5-29
Presslord 5-29

subject to internal audit :)

Link


I'd like to change mine! LOL
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting TampaSpin:
It can't become a named storm yet.......I didn't pick a named storm until mid June in the Contest.......LOL




KEEPEROFTHEGATE 5-28
Caneaddict 5-29
Presslord 5-29

subject to internal audit :)

Link
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The XtremeHurricanes.com live webcam / remote hurricane weather station is now in its 30th hour of continuous operation on batteries.

Viva La Statione! :)
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22. Storm- Haha... I was wondering who was going to acknowledge that question.

From the Doc's blog:
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.
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Thanks for the update Dr. M. Here's to hoping that all our storms become fish!
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Blog Updated

Good morning all! Looks like the surprises of May never end. TD 1 looking proud out there :)
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21. 7544
on aNOTE it has rain 11 straight days in may for miami today will make 12 the last time this happend was 2005 going for a new record n is this a sign of things to come ?
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Thanks again Doc! So what's been the shortest blog between updates? This is by far the shortest for me!
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Thanks Doc! Interesting formation early in the season, but I'm not going to get all excited about it being a signifier of an active season ahead. If it were a Cape Verde storm I think we'd all be singing a different tune. Still, interesting to watch. NHC expects it will be Tropical Storm Ana in 12 hours.
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It can't become a named storm yet.......I didn't pick a named storm until mid June in the Contest.......LOL
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Quoting WeatherStudent:
Thanks for the latest blog update, Dr. Masters! Ladies and gentlemen, so the 2009 Atlantic Hurricane Season gets underway. May we all have a safe season ahead. :)

i concur with your thoughts.... I wish you all a very safe 2009 hurricane season.
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Thank you for the update, Dr. Masters!
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Could it turn out to be an active hurricane season?
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13. 7544
early start to the 2009 season could we see another td beforew june rolls in stay tuned
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Quoting LightningCharmer:
Thank you for the update. Looks like Florida is in for more rain.

NOAA Radar


We just had a decent shower in Tampa. It doesn't even really show up on that radar.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Wow, that was a quick update. I hope this does become a TS because I want to go ahead and get rid of the "A" storm this year.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting LightningCharmer:
Thank you for the update. Looks like Florida is in for more rain.


Ugg, looks like for a while too.

Figures, I've been craving the beach lately.
Thanks, Doc!


Ain't it pretty?
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thanks for the update
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Thanks for the update Dr. Masters


TD-1
Time of Latest Image: 200905281515
2km Storm Relative IR Imagery with BD Enhancement Curve




Member Since: July 3, 2005 Posts: 426 Comments: 128668

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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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