Tropical Depression Three forms

By: Dr. Jeff Masters , 3:42 PM GMT on July 22, 2010

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Tropical Depression Three has formed over the Bahama Islands, and appears poised to become Tropical Storm Bonnie later today. Satellite images of TD 3 show a modest area of heavy thunderstorms that have slowly increased in intensity and areal coverage this morning. The surface circulation center is exposed to view, thanks to strong upper-level winds out of the southwest that are creating about 20 knots of wind shear. This wind shear is due to the counter-clockwise circulation of air around a large upper-level low pressure system over Florida that is moving west at about the same speed TD 3 is. Water vapor satellite loops show a large area of dry air is associated with the upper-level low pressure system, and this dry air is hindering development of TD 3. The storm is attempting to wrap a curved band of clouds around its center, on its west side. If TD 3 is able to do this, the center will be protected from shear and dry air, and more significant strengthening can occur. Surface observations in the Bahamas and several nearby ships have shown top winds in TD 3 of up to 35 mph, so the storm is close to the 40 mph winds needed to be classified as a tropical storm.


Figure 1. Water vapor satellite image showing dry air (brown colors) associated with the upper-level low over Florida. Image credit: NOAA/NESDIS.

Track Forecast for TD 3
The storm is in a fairly straightforward steering current environment, and TD 3 should progress steadily to the west to west-northwest through Saturday. This will bring the storm ashore over the Florida Keys or South Florida on Friday, and into the Gulf of Mexico on Saturday. The latest set of model runs from 2am EDT (6Z) had the advantage of having data from a flight of the NOAA jet last night, so we have higher confidence than usual in the track of TD 3 over the next two days. The location of TD 3's final landfall along the Gulf of Mexico coast has the usual uncertainties for 3 - 4 days, with the various models calling for landfall somewhere between the upper Texas coast and the Florida Panhandle coast. Given the uncertainties, the move halt operations in the Deepwater Horizon blowout recovery effort are probably wise.

Intensity Forecast for TD 3
The primary detriment to development of TD 3 for the next three days will be the presence of the large upper-level low to its west. As long as this low remains in its present location, relative to TD 3, it will bring wind shear of about 20 knots and dry air into the storm. This will limit the intensification potential of TD 3 to no more than about 10 - 15 mph per day. If the upper-level low slow down a bit, relative to TD 3, more shear will affect the storm, potentially weakening it. Conversely, if the upper-level low picks up speed and pulls away from TD 3, the storm may be able to intensify at a faster rate. None of the computer models is calling for that to happen, but it would not take much of an additional separation between TD 3 and the upper level low to substantially reduce shear and allow TD 3 to intensify into a hurricane on Saturday. I put the odds of TD 3 making it to hurricane strength in the Gulf of Mexico at 20%.

98L
An area of disturbed weather (98L) has developed in the Gulf of Mexico's Bay of Campeche. This system is under a low amount of shear, 5 - 10 knots, and may barely have enough time to organize into a tropical depression before making landfall along the Mexican coast a few hundred miles south of the Texas border on Friday.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Next update
I'll have an update between 3 - 4 pm, when the Hurricane Hunters will be in the storm. I'll also speculate on the possible impact the storm will have on the oil spill region.

Jeff Masters

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Quoting MiamiHurricanes09:
The upper low is fading away to the west, doesn't seem like it's having much of an affect on 03L right now. I would put landfall in southern/central Dade county, so a shift towards the right in the 5PM is likely.


What you say makes no sense. The ridge is controlling the track. It is strengthening, driving the westward component of the path faster.
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I'm pretty sure the only hurricane eye that Cantorie has seen is that of Ike, am I correct?
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Quoting mikatnight:
NHC's last pos on 03L was 22.3/74.9........looks like to me it's now (from the 17:45 pic) north of 23 and east of 74.9. I am of course wrong, but, just sayin'...


why does this image give me the creeps lol
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Quoting StormW:
Nice obs Pat...

Folks, let's not freak about the track. Close obs of visible satellite loop imagery indicates that while the center may have shifted somewhat, even if it were to travel more NW than thought, the farthest north it would possibly make it could be Andros Island, before being turned more toward left. So, for a short, it could be a little further right of track, but overall, I feel NHC has a good track at the moment. (36-48 hours)

The ridge is noted building in as we speak.


thank you stormw
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NHC's last pos on 03L was 22.3/74.9........looks like to me it's now (from the 17:45 pic) north of 23 and east of 74.9. I am of course wrong, but, just sayin'...

Member Since: October 18, 2005 Posts: 4 Comments: 3052
Quoting MiamiHurricanes09:
The upper low is fading away to the west, doesn't seem like it's having much of an affect on 03L right now. I would put landfall in southern/central Dade county, so a shift towards the right in the 5PM is likely.
what should i expect in northern broward then if that would happen? also, if the thing really does have 50 mph winds, then it should be a hurricane when it reaches sfla, right?
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Quoting GeoffreyWPB:


Logically...At some point in time, every TS has to be a TD at one point in it's development, however brief. A storm may go from Invest to TS status in the advisories, but that would be because of no recon or insufficient information.


Not necessarily. An open wave can have maximum winds of TS strength, but it is still an open wave. At the point it closes off the circulation it will be a TS without having been a TD. I believe Claudette a number of years ago did just that.
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Hey guys..Storm!! Been a year since I have been on, wanted to say hi to all...missed you guys, looking forward to some tracking!!
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Quoting dwpearson:
Anyone have a link to the live plane data
NHC Aircraft Reconnaissance
Member Since: September 2, 2009 Posts: 130 Comments: 21032
IMO... the latest imagery I have shows the center near 22.6N 74.8W
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Was supposed leave PC Beach to head over to see my mother for a couple days in Orange Beach, AL tomorrow and still plan to but am a little concerned about leaving the wife without a little more certainty as to track and intensity. I assume by tomorrow the models will have a real good grip on it?
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Will StormW be on with Barometer Bob anytime soon?
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Anyone have a link to the live plane data
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Quoting sarahjola:
so where would that put the path and would that change mean that the ull will have less effect on the strength?:)
The upper low is fading away to the west, doesn't seem like it's having much of an affect on 03L right now. I would put landfall in southern/central Dade county, so a shift towards the right in the 5PM cone is likely.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
I think what I am reading on here is that as soon as the recon plane gets back with data, the NHC may update even though it is not the regular time. So, I should check the NHC even before the next regular update, right?
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Well, we know this.. if Cantore shows up in your area.. you are safe! So please post if you see him so we know where the storm is NOT going and we can take it out of the equation. LOL
Member Since: September 18, 2007 Posts: 0 Comments: 1073
Quoting nolauptowngirl:


Nawlins here ... and just as nervous too! Although, I must say, I am a bit more nervous about the oil impact than anything else


Lurking in New Orleans as well...Garden District here. Keeping an eye on this one.
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Quoting AlexEmmett:

no its because the storms are afriad of cantoris pervertness


I thought it was because the storms were scared of 4'11 guys ? j/k I have met Jim before and he a super nice guy
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Quoting mcluvincane:


No Levi. He was wrong on his tidbit yesterday so probably hiding out.


lol
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting StormW:


I think he's recuperating from Calculus!


Ekkkkkk.....yukky! LOL!
Member Since: June 16, 2008 Posts: 0 Comments: 505
Quoting Hurricanes101:
866. mcluvincane 6:26 PM GMT on July 22, 2010

Levi is one of the best on this site from what I have seen over the last few months, no need to point out if a forecast of his doesn't pan out



I know that and look forward in what he has to say. I was joking. Geez
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it was just said on the radio that t.d.3 will be t.s. bonnie tonight
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From the visible images every time a cluster of ts's evolve they get blown off to the NE rapidly.

This will be a very slow developing storm at best.
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Quoting CybrTeddy:


Both are true. I suspect though judging by recon.. 03L might never have been a TD.


Logically...At some point in time, every TS has to be a TD at one point in it's development, however brief. A storm may go from Invest to TS status in the advisories, but that would be because of no recon or insufficient information.
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Quoting Hurricanes101:
866. mcluvincane 6:26 PM GMT on July 22, 2010

Levi is one of the best on this site from what I have seen over the last few months, no need to point out if a forecast of his doesn't pan out

Where's Levi?
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Quoting Patrap:


They pulled the Cantore Cartoon Pic from google. I should of saved dat sucka.



I saved it, let me look for it
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Quoting MiamiHurricanes09:
Under the deepest convection, signs of a strengthening system.
so where would that put the path and would that change mean that the ull will have less effect on the strength?:)
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Quoting StormHype:


No, but if I see Roker I'll be sure to push him off the pier at the height of the storm.


No Cantore sightings yet that I know of... but Abrams is supposed to be in S FL tomorrow starting at 6am
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Quoting Hurricanes101:


or his pic of Jim Cantore?

he did that with Alex lol


They pulled the Cantore Cartoon Pic from google. I should of saved dat sucka.

Member Since: July 3, 2005 Posts: 414 Comments: 125418
Quoting weatherportricheyfl:
BUT IM WORRIED ABOUT a slow track will this be the cASE or will it gain speed


15mph+ Will be here and gone faster than a FL summer time seabreeze tstorm.
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866. mcluvincane 6:26 PM GMT on July 22, 2010

Levi is one of the best on this site from what I have seen over the last few months, no need to point out if a forecast of his doesn't pan out

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Quoting neonlazer:
Hehe...visual satellite *grins* (and low cloud product satellite)


I thought maybe I been missing something for 4 years,LOL
Member Since: July 3, 2005 Posts: 414 Comments: 125418
the latest hwrf plot thru 48hrs looks appropriate IMO....
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Quoting Patrap:
I got a message LSU ESL Server is overloaded.

I WUnder why?



CPU, network or too many connections?
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About JeffMasters

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