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 Hurricanes101:
98L will likely run out of time unless it stalls

20.7N 95.8W is the 18Z coordinates and that is not far offshore


Yep, been saying that today. The NHC said the same thing at the 2pm TWO.
Member Since: July 15, 2006 Posts: 17 Comments: 10157
Not you newbie, the person who answered you...sorry.
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Quoting Hurricanes101:
1143. AlexEmmett 7:09 PM GMT on July 22, 2010

dry air can also cause a center to become exposed

i know that but the upperlevel low is moistening up the area like miami said wait till tonight but i could for a short period of time become exposed
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1168. leo305
Quoting BenBIogger:


Dry air....


there isn't much of it
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Lookin' like imma get wet...!...Soon...LOL.

Member Since: September 2, 2009 Posts: 130 Comments: 21032
I'd say the big $ 64,000 $ ?? is what kind of oil surge can we expect on our bayoufront property?? A washboard GOM may surge to break some of this crud up*** B.P.(Bull poop) should want to suck the oil up so they can make some jack $$$$!!
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Quoting Grothar:
Anyone think this will change a little at 5PM?



Hey Grothar, I wouldn't be surprised if it all shifts a bit north of the current forecast. In less than 2 hours we'll know fer sure.

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1164. Drakoen
TD3 looks like it is heading for the southern mainland of Florida. Turn on the forecast track and you can see it is well north of them.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
1163. unf97
Quoting Grothar:
Anyone think this will change a little at 5PM?



I don't forsee a major shift. If there is a minor deviation, there may be a slight shift east, where I mentioned the target zone for a probable landfall on the Gulf Coast from Central Louisiana to Biloxi, MS.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting StormW:
Is that a pinhole eye?


Oh Lord!! I know YOU were joking, but I'll bet there will be people saying that before long!
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Quoting robinvtx1215:
Cantore was in Galveston when Ike came ashore.

I think that is the only eye he has actually seen, although he sure has seen some nasty eyewalls...
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Quoting ecflweatherfan:
You got stuck in that one too, palmbaywhoo??? LOL

it became a ghost town around here except for that road it seemed.... it was cool to see all the news trucks up and down the beach from all over
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12z ECMWF takes 03L into southern Dade (in line with that I'm thinking) in about 24 hours. It later takes it into Louisiana as a rather weak system.

Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting HurricaneNewbie:

I said logical.. Not definition.


Explain the Salton Sea in California then.
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Quoting Tazmanian:



this time mix oil

lol shes a crude girl lol pun was intended
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Quoting AlexEmmett:

i disagree there no reason for that to happen shear is decreesing


Dry air....
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Am i seeing things or does it look like a very small "eye" forming?
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1143. AlexEmmett 7:09 PM GMT on July 22, 2010

dry air can also cause a center to become exposed
Member Since: March 10, 2010 Posts: 1 Comments: 7233
Quoting StormW:
Is that a pinhole eye?


It looked like an eye! Just an island tho! lol
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Quoting oracle28:
Are the storms along the SE Texas coast related to 98L or just the afternoon heating type?


We are getting some outer "bands"...been hitting all day here in CC TX. Brownsville about to get slugged.
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Doug,
With sheer decreasing, it is much more likely what Drak is hinting at in his posts....center will relocate under the strongest convection

Quoting PensacolaDoug:
LLC is gonna become exposed, I'm thinking.
Member Since: June 28, 2010 Posts: 0 Comments: 706
1147. Grothar
Quoting smmcdavid:


Probably everyone... in all different directions. ;-)


Big LOL!
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1146. Times2
Link

Very Cool Look! Zoom in!
Select the enhancement Feature! color water vapor
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Quoting quante:
Recon has disappeared from my Google Earth. Are they finished already?

show another plane in Gulf, measuring upper air I suppose?


Click on "Mission 02 into Second Suspect Area"
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i know that hurricanes mix up the water column as the pass over head but has there ever been a study of how much the water mixes?

i was thinking that if a hurricane went over the oil disaster area and the cameras were left down around the BOP would they record any difference in conditions? ie. currents or sediment off the bottom?

before anyone takes this the wrong way...i am not wishing it goes over that area just thinking what it would do and if there was ever camera in place to capture that type of event.
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Quoting PensacolaDoug:
LLC is gonna become exposed, I'm thinking.

i disagree there no reason for that to happen shear is decreesing
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1142. xcool
AlexEmmett ha
Member Since: September 26, 2009 Posts: 2 Comments: 15603
Quoting AlexEmmett:

oh crap its katrinas little sister



this time mix oil
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Quoting jscs:


You really should stop watching Faux News.
Never let it be said that I watch any news whose name begins with F...

Current Conditions


Nassau, BS (Airport)
Updated: 9 min 20 sec ago
88 °F / 31 °C
Mostly Cloudy
Humidity: 70%
Dew Point: 77 °F / 25 °C
Wind: 17 mph / 28 km/h / 7.7 m/s from the East
Pressure: 29.97 in / 1015 hPa (Falling)
Heat Index: 100 °F / 38 °C
Visibility: 6.2 miles / 10.0 kilometers
UV: 8 out of 16
Clouds: Mostly Cloudy 1500 ft / 457 m


New update.
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Quoting IKE:
Overall appearance has improved with TD3 since this morning...nice outflow to it. Track looks further north then the NHC had as the track.
Yep. Good to see you on IKE!
Member Since: September 2, 2009 Posts: 130 Comments: 21032
You got stuck in that one too, palmbaywhoo??? LOL
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1136. Ossqss
Just peeked in -- not good



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LLC is gonna become exposed, I'm thinking.
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Quoting PensacolaDoug:



And the GFDL didnt kill it on this run.


Link please. I only see the 12Z (8am runs) on the FSU site. GFDL and HWRF for those show a very lame event.
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1133. quante
Recon has disappeared from my Google Earth. Are they finished already?

show another plane in Gulf, measuring upper air I suppose?
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Quoting Tazmanian:
well now looks like LA is the land fall point

oh crap its katrinas little sister
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Quoting robinvtx1215:
Cantore was in Galveston when Ike came ashore.


So was OZ.
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Quoting ecflweatherfan:
Yeah, I thought so too, neon... but he came to Palm Bay, FL, in the same spot, back in 2004 for Frances and Jeanne... they both came ashore at the same spot 80 miles to the south.

Parked on top of the 95 overpass lol... man that caused a bit of a traffic jam!
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Quoting Grothar:
Anyone think this will change a little at 5PM?



Probably everyone... in all different directions. ;-)
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I think Jeff is trying to put this thing in a wheelbarrel and carry it to his part of town....lol
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well now looks like LA is the land fall point
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Quoting jlp09550:


Nice convection at the center.
The littlr engine that could comes to mind
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98L will likely run out of time unless it stalls

20.7N 95.8W is the 18Z coordinates and that is not far offshore
Member Since: March 10, 2010 Posts: 1 Comments: 7233
1124. IKE
Overall appearance has improved with TD3 since this morning...nice outflow to it. Track looks further north then the NHC had as the track.
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Quoting Tropicaddict:
all of the models have significantly shifted East. All call for a LA landfall....

Link

and all those models are quite far off on initialization. they are way south and west of the coc
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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.