Tropical Depression Three forms

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

Share this Blog
1
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1222 - 1172

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33Blog Index

Quoting rossclick:
are they having a hard time spotting the center?


no
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting StormW:


Don't ya think the best thing to do is to call the Airport? Or visit their website?

Talk about having to state the obvious to the oblivious.
Member Since: Posts: Comments:
are they having a hard time spotting the center?
Member Since: Posts: Comments:
Quoting StormW:
Is that a pinhole eye?


Now don't you go getting banned right now!! ;-)
Member Since: Posts: Comments:
Quoting ElConando:
Taz seriously how many times to we all have to tell you those are not surface winds. They are way up in the atmosphere.




i no but they are march high then what they found last night
Member Since: Posts: Comments:
Quoting leo305:


there isn't much of it


Somebody posted a T-skew from the Bahamas that showed a moderate amount of dry air in the mid-levels.
Member Since: March 19, 2009 Posts: 0 Comments: 1421
1215. RJT185
Quoting StormW:
Is that a pinhole eye?



lol, i just died a little.
Member Since: Posts: Comments:
Ugh, I wish the track consensus would shift OUT of the DWH area! I side with anyone who has been wishcasting for Central to South Florida -- you guys can have it if you want it!
Member Since: Posts: Comments:
Quoting ElConando:
Taz seriously how many times to we all have to tell you those are not surface winds. They are way up in the atmosphere.


Now now grasshopper... slow down :)
Member Since: Posts: Comments:
Quoting StormW:
About another 2 hours, gonna make a left.


a left turn? so you think it will turn more toward the west again?
Member Since: Posts: Comments:
Taz seriously how many times to we all have to tell you those are not surface winds. They are way up in the atmosphere.
Member Since: September 6, 2009 Posts: 2 Comments: 3784


AOI
Member Since: Posts: Comments:
Here in Boynton Beach, I'm expecting occasional showers/squalls tomorrow with winds of 20-30 MPH, maybe gusting to 35 MPH at the worst, as Bonnie, probably with 50-60 MPH sustained winds, passes near the tip of the S. Florida mainland near Key Largo.

No having to gas up the car, no panic shopping in the supermarket, etc. This system for us is interesting to watch without being clobbered.

I hope nobody else gets "clobbered."
Member Since: Posts: Comments:
1205. IKE
Quoting 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.


Agree with you on the track.
Member Since: Posts: Comments:
They used to close MIA @ 40mph
Member Since: Posts: Comments:
Quoting StormW:
About another 2 hours, gonna make a left.


Excatly i dont see what they're seeing
Member Since: Posts: Comments:
Quoting StormW:
About another 2 hours, gonna make a left.


The storm or you?
Member Since: September 6, 2009 Posts: 2 Comments: 3784
in other news look what noaa is finding

Significant Wind Levels...
Level Wind Direction Wind Speed
1017mb (Surface) 85° (from the E) 14 knots (16 mph)
1006mb 85° (from the E) 17 knots (20 mph)
929mb 85° (from the E) 15 knots (17 mph)
880mb 95° (from the E) 9 knots (10 mph)
850mb 100° (from the E) 11 knots (13 mph)
679mb 120° (from the ESE) 29 knots (33 mph)
556mb 110° (from the ESE) 17 knots (20 mph)
491mb 65° (from the ENE) 13 knots (15 mph)
464mb 15° (from the NNE) 12 knots (14 mph)
447mb 30° (from the NNE) 14 knots (16 mph)
405mb 20° (from the NNE) 20 knots (23 mph)
352mb 35° (from the NE) 27 knots (31 mph)
282mb 35° (from the NE) 36 knots (41 mph)
224mb 55° (from the NE) 65 knots (75
mph)
219mb 45° (from the NE) 38 knots (44 mph)
194mb 25° (from the NNE) 34 knots (39 mph)
190mb 40° (from the NE) 40 knots (46 mph)
187mb 20° (from the NNE) 22 knots (25 mph)
177mb 30° (from the NNE) 28 knots (32 mph)
170mb 55° (from the NE) 59 knots (68 mph)
Member Since: Posts: Comments:
Quoting StormW:
About another 2 hours, gonna make a left.
Agreed, I think some of us are forgetting about the rebuilding ridge.
Member Since: Posts: Comments:
1194. Grothar
Quoting mikatnight:


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.



Go ahead make my day! Two hours in a long time at my age.
Member Since: July 17, 2009 Posts: 71 Comments: 27210
I ain't on here much no more but I say this looks like it got Sarasota wrote all over it.
Member Since: Posts: Comments:
Quoting asgolfr999:


Enclosed saltwater bodies of water are often referred to as seas as opposed to lakes..and don't jump, I said often not always.



Ok. Now explain the "Great Salt Lake".


LOL
Member Since: Posts: Comments:
NHC TWO said that 98L might be inhibited by land interaction.. not landfall. So far however, 98L hasn't been showing that.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting sammywammybamy:
ARE THEY GOING TO CLOSE MIAMI INTERNATIONAL AIRPORT?

HOW WILL THIS CHANGE THE FLIGHT PLAN?


Somebody who lives in Miami answer her question!!!
Member Since: Posts: Comments:
Quoting 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.


you are correct Drakoen !!!
Member Since: Posts: Comments:
Quoting tropicfreak:
So what do you think of 98L? Does it look like a TD? I mean it looks very organized.



i say 98L is a TD most likey they will upgrade it at post season
Member Since: Posts: Comments:
i wouldnt be surprised if ts watches extended much further north at 5pm
Member Since: Posts: Comments:
Quoting jscs:


You really should stop watching Faux News.
we should really stick to weather. no reason to take up space on what news station is worth viewing. i'm sure others on here would say the same about cnn or msnbc or hln.
Member Since: September 10, 2008 Posts: 0 Comments: 1294
Quoting MississippiWx:


Yep, been saying that today. The NHC said the same thing at the 2pm TWO.


2pm TWO says it still has a day or two, so not they did not acknowledge that
Member Since: March 10, 2010 Posts: 1 Comments: 7874
1182. leo305
Quoting weathersp:
1006.4 mb on the recon.. they also went up to 1,500 ft... I guess 500ft was getting a bit to much.


there's an eruption of convection over the center on Visible, so I guess that's why.

Member Since: Posts: Comments:
Quoting 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.


Agreed. Been saying that all morning and afternoon now.
Member Since: Posts: Comments:
So what do you think of 98L? Does it look like a TD? I mean it looks very organized.
Member Since: Posts: Comments:
i see no one on here can take jokes lol
Member Since: Posts: Comments:
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.


appears ECMWF brings TD3 across SFL and loses it? It never really did develop this did it?

looks like 1157 explained it thanks.
Member Since: Posts: Comments:
1006.4 mb on the recon.. they also went up to 1,500 ft... I guess 500ft was getting a bit to much.
Member Since: Posts: Comments:
Quoting Baybuddy:


Explain the Salton Sea in California then.


Enclosed saltwater bodies of water are often referred to as seas as opposed to lakes..and don't jump, I said often not always.
Member Since: Posts: Comments:
Quoting StormW:
Is that a pinhole eye?


Nic try Storm W yoo are re ported.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
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: Posts: Comments:

Viewing: 1222 - 1172

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33Blog Index

Top of Page

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.

Local Weather

Mostly Cloudy
38 °F
Mostly Cloudy

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron