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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1622. centex
2:26 AM GMT on July 23, 2010
Commenting on lots of post will make my own. Bonnie all depends on ULL. If ULL give it half a chance it will take advantage of it. This system has lots of moxy, you will not find this in reviewed literature. While high will push west and be big story tomorrow and model will shift a little left, I would still not focus on 2nd land fall, too early. They will shift again on Saturday. But it does look like eventual SE TX or LA landfall. This will push the oil around. Some new areas will get oil. S. Fl will get lots of rain tomorrow maybe someone post the estimates. Bonnie is about to hit the eastern edge of ridge which will push it west. It’s only ULL and dry air which is keeping Bonnie down. In a way Bonnie will follow the ULL west. The only part I don’t understand is how the ULL will affect track in this situation.
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1621. centex
2:10 AM GMT on July 23, 2010
Quoting OracleDeAtlantis:
It looks to me like this ULL is beginning to outpace the surface low. Not good news ... for the Gulf Coast. These people are crazy to underestimate this one, and by "these people," I mean the same people who underestimated that killer back in 2005.
I would believe that except people have been saying that for two days. Our local texas mets said last night the ULL wouod be in TX sunday, that not far behind Bonnie.
Member Since: August 10, 2007 Posts: 0 Comments: 3217
1620. HarleyStormDude52
11:34 PM GMT on July 22, 2010
Quoting theBlur:


It's like baseball - if it were not for drinking beer and second guessing (umps, pitchers, coaches, etc), nobody would watch. ☺


Kind of like IKE... It wobbled a bit and changed course a few times before it got on a path to Hou/Galv
Member Since: July 8, 2010 Posts: 0 Comments: 345
1619. Chucktown
10:17 PM GMT on July 22, 2010
wtnt63 knhc 222214
tcuat3

tropical depression three tropical cyclone update
nws tpc/national hurricane center miami fl al032010
615 pm edt thu jul 22 2010

...depression becomes tropical storm bonnie...

data from an air force hurricane hunter reconnaissance aircraft during the past hour indicate that surface winds associated with the depression have increased to 40 mph...65 km/hr...and that the depression has become a tropical storm.


summary of 615 pm edt...2215 utc...information
--------------------------------------------------
location...22.9n 75.4w
about 200 mi...320 km se of nassau
about 415 mi...670 km ese of key west florida maximum sustained winds...40 mph...65 km/hr present movement...nw or 315 degrees at 14 mph...22 km/hr minimum central pressure...1005 mb...29.68 inches
Member Since: August 27, 2006 Posts: 0 Comments: 1664
1618. Chucktown
10:16 PM GMT on July 22, 2010
Bonnie !!
Member Since: August 27, 2006 Posts: 0 Comments: 1664
1617. OracleDeAtlantis
10:00 PM GMT on July 22, 2010
It looks to me like this ULL is beginning to outpace the surface low. Not good news ... for the Gulf Coast. These people are crazy to underestimate this one, and by "these people," I mean the same people who underestimated that killer back in 2005.
Member Since: August 27, 2009 Posts: 0 Comments: 489
1616. theBlur
9:50 PM GMT on July 22, 2010
Quoting TexasGulf:

Yet, as guys, we will sit here drinking a beer and second-guessing the computer models based on instinct.


It's like baseball - if it were not for drinking beer and second guessing (umps, pitchers, coaches, etc), nobody would watch. ☺
1615. Baybuddy
9:03 PM GMT on July 22, 2010


I guess I have it made, my wife does my second guessing for me.
Member Since: June 26, 2006 Posts: 0 Comments: 1115
1614. 1fromnovasscotia
8:55 PM GMT on July 22, 2010
Chad Meyers stated a few minutes ago that this storm has 0% chance of developing into a hurricane according the NHC, well i hope not those that it will affect but at the same time its a bold statement considering the fetch or distance it has to travel, there reasonning the amount of windshear inside the gulf. what are your thought's about that bloggers
1613. GetReal
8:53 PM GMT on July 22, 2010


TD#3 is continuing to slowly become better organized... There is new convection blowing up on the SW side of the COC...
Member Since: July 4, 2005 Posts: 204 Comments: 8802
1612. Clearwater1
8:45 PM GMT on July 22, 2010
Quoting hurricanejunky:
It's absolutely north of the forecast points:

Link


The 5pm track is out and if you go to the archive of tracks for this storm they are kind of interesing. Run the loop and see
Member Since: August 26, 2006 Posts: 0 Comments: 1547
1611. hurricanejunky
8:44 PM GMT on July 22, 2010
This may be the most tightly clustered I've seen the models in quite some time. How about you guys?
Member Since: August 28, 2006 Posts: 6 Comments: 2895
1610. TampaTom
8:44 PM GMT on July 22, 2010
Quoting hurricanejunky:
It's absolutely north of the forecast points:

Link


Gotta sign in...
Member Since: June 20, 2005 Posts: 22 Comments: 1050
1609. hurricanejunky
8:42 PM GMT on July 22, 2010
It's absolutely north of the forecast points:

Link
Member Since: August 28, 2006 Posts: 6 Comments: 2895
1608. Clearwater1
8:37 PM GMT on July 22, 2010
Quoting TexasGulf:


That goes against our nature as guys.

The U.S. has spent $Billions on the NHC, NOAA, NASA, NWS on satellites, radar systems, weather buoys, computer modeling systems, research planes and compiling a 100-years worth of research on tropical storm systems. All of that has culminated in producing the sophisticated models that are now telling us where the TD3 is projected to go and how strong it will be.

Yet, as guys, we will sit here drinking a beer and second-guessing the computer models based on instinct.


That's what makes a blog of this nature intersting and fun. If we all just agreed with one another it would be boring. If we agreed with the NHC (which of course we should do) then we would really have no one to second guess at 5, 8, 11 and so on.
Member Since: August 26, 2006 Posts: 0 Comments: 1547
1607. catastropheadjuster
8:35 PM GMT on July 22, 2010
Just thought I would throw this in. My son just called he in Grand Isle,LA working and he just told me that tommorrow morning there suppose to start evacuating grand isle, he want be leaving until 20yrs before it comes in, there take the cranes apart and everything. He called me to let me know, I told him I didn't think it was gonna get bad. Heck I just don't know what to think.
Sheri
Member Since: August 24, 2006 Posts: 21 Comments: 3648
1606. Edisonian
8:35 PM GMT on July 22, 2010
WSVN ch 7 just said that as of 5:00 per NHC TD3 has NOT strengthened, still a depression.
Member Since: July 20, 2010 Posts: 0 Comments: 17
1605. tomas5tex
8:35 PM GMT on July 22, 2010
Issued at: 4:31 PM EDT 7/22/10 (gateway).


Air force reconnaissance plane finds that the tropical depression has not strengthened,

Summary of 500 pm edt, 2100 utc, information ---------------------------------------------- location, 22.7n 75.4w about 205 mi, 325 km se of nassau about 425 mi, 685 km ese of key west Florida maximum sustained winds, 35 mph, 55 km/hr present movement, nw or 310 degrees at 14 mph, 22 km/hr minimum central pressure, 1006 mb, 29.71 inches

Watches and warnings -------------------- changes with this advisory,

Member Since: August 31, 2006 Posts: 0 Comments: 119
1604. TexasGulf
8:32 PM GMT on July 22, 2010
Quoting leelee75k:
Can't you guys just admit at this time none of you are certain and you could either be right or wrong?



That goes against our nature as guys.

The U.S. has spent $Billions on the NHC, NOAA, NASA, NWS on satellites, radar systems, weather buoys, computer modeling systems, research planes and compiling a 100-years worth of research on tropical storm systems. All of that has culminated in producing the sophisticated models that are now telling us where the TD3 is projected to go and how strong it will be.

Yet, as guys, we will sit here drinking a beer and second-guessing the computer models based on instinct.
Member Since: April 28, 2008 Posts: 0 Comments: 354
1603. bohonkweatherman
8:27 PM GMT on July 22, 2010
Quoting TexasGulf:
I was just North of Houston for T.S. Allison. The flooding was due to the tropical storm / depression circling back over the Houston area twice during a 4-day period, in some areas raining over 25" during that time.

You can never discount a storm based on category or wind speed. Each has the potential to spawn tornadoes, cause flash flooding, cause power outages or even loss of life & property damage. While most tropical storms or depressions are relatively mild... some can pack a serious punch.

TD3 (Bonnie) may be just such a storm. It may not seriously intensify beyond TS strength... but it could cause serious environmental damage due to the oil spill in it's path. Based on wind and wave patterns and how far it moves the oil on-shore, particularly into the Louisiana coastal marsh land, this small TS could cause environmental devastation on a large scale.

Not everything about a storm's destructive power is about houses, property or lives. In this case, the oil spill being an extenuating factor, it could be an ecological disaster for the western Louisiana coastal marsh land, which so far has been relatively untouched by the oil.
Very true, my wife lived in Jersey Village at the time and it was unbelievable, hopefully this system never stalls. Let it keep moving at a good rate of speed then it will not be so bad anywhere.
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1602. wayfaringstranger
8:24 PM GMT on July 22, 2010
Quoting bohonkweatherman:
No the dude is stating the way it is.


It was a joke - Im sure you understand?
Member Since: July 12, 2010 Posts: 0 Comments: 235
1601. Clearwater1
8:23 PM GMT on July 22, 2010
Quoting MiamiHurricanes09:
Wobble? It's north of the cone and has been moving NW for a a couple hours. And of course when you know you are wrong you resort to my age. Typical.
You could be right. If is heading at an angle, say n w from the offical track, then the longer it moves in that direction the greater the spread from the nhc track.
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1600. TexasGulf
8:20 PM GMT on July 22, 2010
I was just North of Houston for T.S. Allison. The flooding was due to the tropical storm / depression circling back over the Houston area twice during a 4-day period, in some areas raining over 25" during that time.

You can never discount a storm based on category or wind speed. Each has the potential to spawn tornadoes, cause flash flooding, cause power outages or even loss of life & property damage. While most tropical storms or depressions are relatively mild... some can pack a serious punch.

TD3 (Bonnie) may be just such a storm. It may not seriously intensify beyond TS strength... but it could cause serious environmental damage due to the oil spill in it's path. Based on wind and wave patterns and how far it moves the oil on-shore, particularly into the Louisiana coastal marsh land, this small TS could cause environmental devastation on a large scale.

Not everything about a storm's destructive power is about houses, property or lives. In this case, the oil spill being an extenuating factor, it could be an ecological disaster for the western Louisiana coastal marsh land, which so far has been relatively untouched by the oil.
Member Since: April 28, 2008 Posts: 0 Comments: 354
1599. TropicalNonsense
8:19 PM GMT on July 22, 2010
Quoting Jeff9641:


Miami, I wouldn't respond to some of these fools. Obvisouly this is coming to SE FL and people want to argue that because they want it to come to where they live in TX or LA. LA after FL looks like the next landfall.


you have to be kidding. you dont really believe this i hope.
[TD/Bonnie] will not impact Florida other than the key's Jeff.

i know you were just joking but dont scare the Florida
folks they cant take it after the 2004 season!

Member Since: July 3, 2007 Posts: 0 Comments: 524
1598. bohonkweatherman
8:17 PM GMT on July 22, 2010
Quoting wayfaringstranger:


Shrink casting?
No the dude is stating the way it is.
Member Since: July 5, 2009 Posts: 0 Comments: 1348
1597. TampaTom
8:16 PM GMT on July 22, 2010
Quoting StormHype:


That goes against the NHC and models in both track and intensity, but then again, any kid with a photo of the NHC for their avatar must know what they are doing. I'm just a monkey.


Wait a minute.. I thought I had the monkey avatar...
Member Since: June 20, 2005 Posts: 22 Comments: 1050
1595. leelee75k
8:14 PM GMT on July 22, 2010
Can't you guys just admit at this time none of you are certain and you could either be right or wrong?

TD3/Bonnie center could go through the Keys but the blob of convection could affect Miami/Broward and if you are paying attention to official sources, ie the flood watch and tropical storm warning, then that is what is to be expected.

agree to disagree and move on, please!
Member Since: September 9, 2005 Posts: 0 Comments: 557
1594. StonedCrab
8:13 PM GMT on July 22, 2010
Quoting cchsweatherman:


I am still sticking with my forecast from earlier with a moderate tropical storm making landfall in Southern Miami Dade county tomorrow afternoon.


Good call! Let's Party! Two people agree on the blog!
Member Since: October 30, 2007 Posts: 0 Comments: 270
1593. wayfaringstranger
8:13 PM GMT on July 22, 2010
Quoting HurricaneFCast:
NHC's coordinates at 2pm were 22.3N, 74.9W...
Latest coordinates from recon: 22.4N, 75.1W... 2 tenths west, 1 tenth north.. The steering has been and will continue to be a straightforward WNW motion... Not a single hurricane expert has every wavered from that forecast.. What is happening on this blog is called an extremely overactive imagination driven by a subconscious desire for a landfall closer to home.. That's all.. To deny it is dishonest.


Shrink casting?
Member Since: July 12, 2010 Posts: 0 Comments: 235
1592. caribbeantracker01
8:13 PM GMT on July 22, 2010
based on infared sat i believe the center has just improved with a small burst of convection notice the small convection and not the othe blob i think bonnie will be born soon and in my opinion it supports a steady north western movemement but notice the ull rapid sw movement
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1590. PensacolaDoug
8:11 PM GMT on July 22, 2010
Yall do know there is a NEW BLOG up?
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1589. rmbjoe1954
8:11 PM GMT on July 22, 2010
Quoting StormHype:


That goes against the NHC and models in both track and intensity, but then again, any kid with a photo of the NHC for their avatar must know what they are doing. I'm just a monkey.


Great. A Monkey-caster!
Member Since: June 16, 2005 Posts: 0 Comments: 1015
1588. StadiumEffect
8:10 PM GMT on July 22, 2010
In terms of structure, the depression seems like it is better organized. However, heavy thunderstroms are still not properly co-located with the center of circulation and the system is having trouble developing bands on its western side due to shear. The center looks like it may become exposed again if convection is not able to persist over it.
1587. StormHype
8:09 PM GMT on July 22, 2010
Quoting TropicalNonsense:


haha. that is also where the hurricane center is.
Bonnie is unlikely to affect Miami by virtually
everyone's forecast except Miami's. LOL


The miami 'me' casters must be latching on the Clipper 5 model run. lol why do they even plot that?
Member Since: May 31, 2007 Posts: 0 Comments: 1189
1586. TropicalNonsense
8:09 PM GMT on July 22, 2010
Quoting MiamiHurricanes09:
Wobble? It's north of the cone and has been moving NW for a a couple hours. And of course when you know you are wrong you resort to my age. Typical.


Not if you believe Gator23! [Laughs]
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1585. shfr173
8:09 PM GMT on July 22, 2010
1st time weather geek whats new with TD3?
Member Since: September 4, 2008 Posts: 0 Comments: 74
1584. ElConando
8:08 PM GMT on July 22, 2010
Remember so you know google earth does not show surface winds only flight level.
Member Since: September 6, 2009 Posts: 2 Comments: 3709
1583. xcool
8:08 PM GMT on July 22, 2010
new blog
Member Since: September 26, 2009 Posts: 2 Comments: 15603
1582. MrJoeBlow
8:08 PM GMT on July 22, 2010
Quoting btwntx08:

according to this yep


Now look at that it got the XTRP model all over it and it got Sarasota on it for certain. Ya'll was pulling my leg!
1581. HurricaneFCast
8:07 PM GMT on July 22, 2010
NHC's coordinates at 2pm were 22.3N, 74.9W...
Latest coordinates from recon: 22.4N, 75.1W... 2 tenths west, 1 tenth north.. The steering has been and will continue to be a straightforward WNW motion... Not a single hurricane expert has every wavered from that forecast.. What is happening on this blog is called an extremely overactive imagination driven by a subconscious desire for a landfall closer to home.. That's all.. To deny it is dishonest.
Member Since: April 20, 2007 Posts: 7 Comments: 1482
1580. TropicalNonsense
8:07 PM GMT on July 22, 2010
Quoting galvestonhurricane:
Miami Hurricane: td 3 is not going to hit Miami. You need to stop wishcasting; we all know that you want a tropical storm or hurricane.


haha. that is also where the hurricane center is.
Bonnie is unlikely to affect Miami by virtually
everyone's forecast except Miami's. LOL
Member Since: July 3, 2007 Posts: 0 Comments: 524
1579. louisianaboy444
8:07 PM GMT on July 22, 2010
Quoting Jeff9641:


Miami, I wouldn't respond to some of these fools. Obvisouly this is coming to SE FL and people want to argue that because they want it to come to where they live in TX or LA. LA after FL looks like the next landfall.


I give up! lol
Member Since: August 29, 2006 Posts: 22 Comments: 1339
1578. Hurricanes12
8:07 PM GMT on July 22, 2010
Bill Read, director of the National Hurricane Center said that they do expect it to become a weak tropical storm within the next 24 hours and that the NHC does not expect the storm to intensify rapidly. Also, Bill said that the storm itself looks better organized.
Member Since: June 21, 2010 Posts: 0 Comments: 528
1576. vortextrance
8:07 PM GMT on July 22, 2010
I think a slight shift to the north will come next advisory. As for the development I don't think she is doing is great as some do. Shear has relaxed, and even though their is less dry air to the west it is still causing problems. If the current trends continue then tonight might give her a better chance to get her act together. Hopefully she/it will keep choking on the dry air.
Member Since: October 5, 2005 Posts: 0 Comments: 700
1575. chrisdscane
8:06 PM GMT on July 22, 2010
Quoting Patrap:
NEXRAD Radar
Miami, Velocity Azimuth Display Wind Profile Range 124 NMI





plz plz link the site
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1574. tropicfreak
8:06 PM GMT on July 22, 2010
NEW BLOG
Member Since: September 2, 2006 Posts: 110 Comments: 6814
1573. MiamiHurricanes09
8:06 PM GMT on July 22, 2010
NEW BLOG!
Member Since: September 2, 2009 Posts: 130 Comments: 21032
1572. TankHead93
8:06 PM GMT on July 22, 2010
This little bugger may be a big problem for someone down the road. It is VERY persistent... and systems that are persistent in the face of unfavorable conditions (which this one WAS in) become a problem when faced with favorable conditions... JMHO ;)
Member Since: August 12, 2009 Posts: 0 Comments: 203

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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.