Tropical Storm Don forms in the Gulf of Mexico

By: Dr. Jeff Masters , 9:29 PM GMT on July 27, 2011

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Tropical Storm Don, the fourth tropical cyclone of the 2011 season, has formed in the Gulf of Mexico just north of the Yucatan Peninsula. Hurricane Hunters began investigating the system earlier this afternoon and quickly found a closed surface circulation. As the mission continued to gather data from what was thought to be a tropical depression at the time, winds of around 39 mph were found, as well as a 1001 mb central pressure, bringing the system up to tropical storm strength.


Figure 1. Satellite loop of Tropical Storm Don. This loop will stay current.

The official forecast for Don agrees with what most of the models have been suggesting over the past 24 hours. Don will make its way toward the northwest over the next 48 hours before making landfall somewhere between Brownsville and Galveston. The statistical models tend to suggest a more southerly track toward Brownsville, and the dynamical models are forecasting anything from Corpus Christi to Galveston. They all tend to agree landfall will occur late on the 29th (Friday night). Whether or not Don will reach hurricane status is still in question. The Hurricane Center's initial forecast is that Don will remain a tropical storm until landfall. Today some models were intensifying Don to a strong tropical storm, but none crossed the hurricane threshold. Now that we have data from aircraft reconnaissance, the models will be able to get a better handle on potential intensity. The runs that occur later tonight and early tomorrow will have much less uncertainty than those from today.


Figure 2. Model forecast tracks for Tropical Storm Don as of Wednesday afternoon.

I believe Jeff will be back tomorrow for an update.

Angela

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876. CanesfanatUT
1:17 AM GMT on July 28, 2011
Quoting KoritheMan:


Well, the northeastern side is rather disheveled at the moment. There's no denying that.


Disheveled - that's my new word for the week. It was tepid.
Member Since: September 3, 2007 Posts: 0 Comments: 519
875. KoritheMan
1:17 AM GMT on July 28, 2011
Quoting louisianaboy444:


I'm not overly impressed with this really strengthening much..to be quite honest


It has some obstacles to overcome, to be sure. But I honestly think current convective trends are entirely irrelevant to the long term intensity of the system. He is going through the diurnal minimum, northeasterly shear, as well as interaction with the Yucatan Peninsula. This is to be expected.
Member Since: March 7, 2007 Posts: 521 Comments: 19109
874. Hurricanejer95
1:17 AM GMT on July 28, 2011
CIMSS showing 999mb pressure

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 28 JUL 2011 Time : 001500 UTC
Lat : 22:27:13 N Lon : 87:29:53 W


CI# /Pressure/ Vmax
3.0 / 999.5mb/ 45.0kt


Final T# Adj T# Raw T#
3.0 3.1 3.1

Center Temp : -30.7C Cloud Region Temp : -49.3C

Scene Type : CURVED BAND with 0.58 ARC in LT GRAY

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 40km
- Environmental MSLP : 1013mb

Satellite Viewing Angle : 29.8 degrees

Member Since: August 30, 2008 Posts: 1 Comments: 224
872. floridaboy14
1:16 AM GMT on July 28, 2011
Quoting Levi32:


Same kind of deal. The steering is very similar above about 700-600mb.

whats causing convection to wain by the center but fire up over the yucatan? Diurnal minimum?, shear? dry air? land proximity?
Member Since: July 25, 2011 Posts: 0 Comments: 1102
871. GHOSTY1
1:16 AM GMT on July 28, 2011
Now I'm officially leaving to go to dinner and will be back later!
Member Since: July 25, 2011 Posts: 0 Comments: 453
870. KoritheMan
1:16 AM GMT on July 28, 2011
Quoting stormwatcherCI:
Kori, the crow is ready whenever you are :) Now, thoughts on the wave in the eastern Caribbean and the one around 35W ?


The one around 35W could be a big player down the road. The GFS keeps an anticyclone more or less collocated with it until it reaches the Caribbean, enabling it to escape the strong belt of zonal (westerly) shear forecast to lie to the north of the system.

The other wave also needs to be watched, but if it does develop, it's going into Central America most likely, as the ridge steering Don restrengthens.
Member Since: March 7, 2007 Posts: 521 Comments: 19109
869. MississippiWx
1:16 AM GMT on July 28, 2011
Convergence is still weak and broad with Don, telling us that the low still has a lot of work to do before it can become strong enough to be a hurricane:

Member Since: July 15, 2006 Posts: 17 Comments: 10156
868. TropicalAnalystwx13
1:15 AM GMT on July 28, 2011
Quoting mojofearless:


Ahead of themselves? I start stocking up a little at a time the first week of January every year. Now that Cape Verde season is here, I only need to get shelf stable milk and shelf stable bacon. And some decent vodka. And when Halloween approaches, I rotate/use what needs to be used, finish it off by Christmas, and start all over again in January.
It's never too early.


Awwww man! Now I want bacon!

Darn it...We don't have any. Now I'm sad :(
Member Since: July 6, 2010 Posts: 108 Comments: 30237
867. JLPR2
1:15 AM GMT on July 28, 2011
There is another weak spin to the SE of the CV islands.



Those little spins are becoming more frequent.
Member Since: September 4, 2007 Posts: 7 Comments: 8459
866. sunlinepr
1:15 AM GMT on July 28, 2011
Blog Posting in High: Peaking 12 posts per minute

Member Since: August 2, 2010 Posts: 21 Comments: 9648
865. FLWeatherFreak91
1:15 AM GMT on July 28, 2011
We may see a weakening of the low level circulation if this trend continues. It needs convection to carry into nighttime or it will start over closer to the yuc.
Member Since: December 1, 2006 Posts: 2 Comments: 3616
864. Tazmanian
1:14 AM GMT on July 28, 2011
Quoting CanesfanatUT:


LOLZ - Taz, you are a devil. Keep on keepin' on main.



ok
Member Since: May 21, 2006 Posts: 5089 Comments: 114024
863. CanesfanatUT
1:14 AM GMT on July 28, 2011
Quoting Tazmanian:



hi eek nic too meet you am Emily lol this kinding


LOLZ - Taz, you are a devil. Keep on keepin' on main.
Member Since: September 3, 2007 Posts: 0 Comments: 519
862. mojofearless
1:13 AM GMT on July 28, 2011
Quoting TxHurricanedude11:

those people might be getting ahead of themselves


Ahead of themselves? I start stocking up a little at a time the first week of January every year. Now that Cape Verde season is here, I only need to get shelf stable milk and shelf stable bacon. And some decent vodka. And when Halloween approaches, I rotate/use what needs to be used, finish it off by Christmas, and start all over again in January.
It's never too early.
Member Since: August 13, 2009 Posts: 0 Comments: 172
861. OracleDeAtlantis
1:13 AM GMT on July 28, 2011
Quoting 1900hurricane:
In the short term, Don needs to move away from the Yucatan Peninsula to begin strengthening. The daytime heating over the landmass is robbing some of Don's instability. This can be seen in the AVN IR loop, which shows the warming of Don's core while the band over the Yucatan remains intense with cold cloud tops. The transition into nighttime may be a temporary solution to this.



Click on the image to view it as an animated flash loop.
As I recall from memory, the Yucatan tip has never been overly friendly to any system that has passed too close by.
Member Since: August 27, 2009 Posts: 0 Comments: 489
860. Levi32
1:13 AM GMT on July 28, 2011
Quoting TropicalAnalystwx13:


What if it becomes a hurricane?


Same kind of deal. The steering is very similar above about 700-600mb.
Member Since: November 24, 2005 Posts: 628 Comments: 26452
859. stormwatcherCI
1:13 AM GMT on July 28, 2011
Quoting KoritheMan:


Well, the northeastern side is rather disheveled at the moment. There's no denying that.
Kori, the crow is ready whenever you are :) Now, thoughts on the wave in the eastern Caribbean and the one around 35W ?
Member Since: October 9, 2008 Posts: 0 Comments: 8242
858. louisianaboy444
1:12 AM GMT on July 28, 2011
Quoting KoritheMan:


Well, the northeastern side is rather disheveled at the moment. There's no denying that.


I'm not overly impressed with this really strengthening much..to be quite honest
Member Since: August 29, 2006 Posts: 22 Comments: 1339
857. Tazmanian
1:12 AM GMT on July 28, 2011
Quoting toasterbell:
Heh, sorry guys, but I have to announce that it'll hit Galveston fair and square, but only because I am supposed to move to a new apartment there on Friday and Saturday :-P. It figures that since people think I'm crazy for moving to a town that gets tropical storms, I'll end up moving IN a tropical storm! Hehehe... I'm just hoping that wherever it hits (near or far), somebody who needs it will get the rain.

-Gypsy (generally just a lurker)

P.S. - I also just washed my car.




if you guys want rain in TX wash your Care
Member Since: May 21, 2006 Posts: 5089 Comments: 114024
856. toasterbell
1:11 AM GMT on July 28, 2011
Heh, sorry guys, but I have to announce that it'll hit Galveston fair and square, but only because I am supposed to move to a new apartment there on Friday and Saturday :-P. It figures that since people think I'm crazy for moving to a town that gets tropical storms, I'll end up moving IN a tropical storm! Hehehe... I'm just hoping that wherever it hits (near or far), somebody who needs it will get the rain.

-Gypsy (generally just a lurker)

P.S. - I also just washed my car.
Member Since: August 21, 2008 Posts: 0 Comments: 8
855. TropicalAnalystwx13
1:11 AM GMT on July 28, 2011
Quoting HCW:


Why would you BEWARE when everybody knows that Jim Cantorie is the storm shield and he has had only 1 strike since he has been at TWC


You have that backwards. Everyone knows, wherever Jim Cantore is, you better start preparing.
Member Since: July 6, 2010 Posts: 108 Comments: 30237
854. GHOSTY1
1:11 AM GMT on July 28, 2011
I agree with Levi the majority of the models still aim for Corpus Christi region but the models continuously change and its possible that "dare say I" it hits Louisiana but i still feel thats a very dismal chance of happening!
Member Since: July 25, 2011 Posts: 0 Comments: 453
853. HurricaneHunterJoe
1:10 AM GMT on July 28, 2011
Models score on Tropical Storm Don are abysmal!! most didnt even see it. why did the nam pretty much nailit?
Member Since: September 18, 2010 Posts: 0 Comments: 4570
852. KaNaPaPiJoSa
1:10 AM GMT on July 28, 2011
Quoting toasterbell:
Heh, sorry guys, but I have to announce that it'll hit Galveston fair and square, but only because I am supposed to move to a new apartment there on Friday and Saturday :-P. It figures that since people think I'm crazy for moving to a town that gets tropical storms, I'll end up moving IN a tropical storm! Hehehe... I'm just hoping that wherever it hits (near or far), somebody who needs it will get the rain.

-Gypsy (generally just a lurker)

P.S. - I also just washed my car.


that's enough scientific proof for me....
Member Since: June 14, 2010 Posts: 0 Comments: 57
851. animalrsq
1:10 AM GMT on July 28, 2011
Quoting louisianaboy444:
The best tool for any forecaster as he gains experience is Analogue forecasting which is basically saying I've seen this setup before what happened then?..What scares me about modern day Meteorology is that we are not learning from our mistakes as forecasters. The models could be showing something for one setup and then the final result is not what we expected. Instead of saying, man when A is here and B is here this happened so let me not make that mistake again, were basically relying on these computers to not make the same mistake again and most likely we will. Computers have helped the ability to learn but also have hindered it


+++++
Member Since: August 4, 2006 Posts: 0 Comments: 214
Quoting MississippiWx:
With the convection waning like it is, this could be where that center reformation comes into play. The NHC mentioned that a center reformation was possible later tonight because of the elongated nature of the center.

Don has really lost any inner core that he had built, though. Going to have to start all over tonight:

Looks to me like the wave axis from Don and the Yucatan's seabreeze acted in conjunction to lower pressures over land and elongate the circulation. Don should be set for gradual intensification as he pulls away from the Yucatan
Member Since: December 1, 2006 Posts: 2 Comments: 3616
Quoting louisianaboy444:
I look at the pattern and all the possibilities that could ensue so many professional forecasters are getting so wiped by these models(most of you on here)...where's the gut feeling?...where's the experience...i can remember a conversation 2 nights ago when people acted like i was crazy when i said 90L still had a chance because "ooo the models show squat and La la la..let me tell you something that i think everyone is starting to see...our models need serious work because they are trash...I dont need a computer to tell me what's going to happen i can look at things myself and by my own experiences make an educated guess


exactly! I have been saying the same and made a similar statement last week when masters was talking about how none of the reliable computer models developed 90L. I stated the same thing you just said and where are all those reliable models now? The one reliable "so called" model spoken of was forecasting "Don" to form near the Bahamas> I think that was an Epic Fail.

I stated that we need to look at all the models and make our best guess at what will happen. I stated that the computer models are just that "Models" and should not be making the predictions for us.
Member Since: Posts: Comments:
Evening all! Just spoke on the cell to CycloeOz (Brian Osbourne) he is heading toward Corpus Cristi for his live feed. He is going there as we figure that was a good place to start as a possible land fall system.
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Quoting Levi32:


I think those tracks are only possible if Don weakens and falls apart on his journey across the gulf. If it stays a solid tropical storm, then I still think south-central Texas is the target.


Thanks Levi.
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Quoting Chicklit:
The most exciting thing about Don is it's headed for Texas. Other than that, it's a dud.


Oooooh. That's cold. :-)

What I find exciting/interesting about Don Of The Dead is how he was all but written off before making a strong comeback. We don't know just how strong yet, but there's clearly something amiss in the forecasting this year.
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845. jpsb
Quoting MississippiWx:


I'd have a hard time believing anything further east than Houston. I think Houston has just as good of a chance as Corpus Christi. We'll have a really good idea tomorrow after the NOAA jets sample the atmosphere and put the info into the models.

Yes, I agree, models need more-better info and a few runs to sort things out. The strong west, weak north Levi thing sounded good this AM, but I am getting the feeling that conditions are changing in the gulf. That theory may not longer be applicable.
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Quoting TropicalAnalystwx13:


What makes you say that?


Well, the northeastern side is rather disheveled at the moment. There's no denying that.
Member Since: March 7, 2007 Posts: 521 Comments: 19109
Quoting TropicalAnalystwx13:


What makes you say that?


The fact that there are no cold cloud tops over the center anymore.
Member Since: July 15, 2006 Posts: 17 Comments: 10156
842. HCW
Quoting hamla:
where is jim cantorie going to set up BEWARE


Why would you BEWARE when everybody knows that Jim Cantorie is the storm shield and he has had only 1 strike since he has been at TWC
Member Since: Posts: Comments:
In the short term, Don needs to move away from the Yucatan Peninsula to begin strengthening. The daytime heating over the landmass is robbing some of Don's instability. This can be seen in the AVN IR loop, which shows the warming of Don's core while the band over the Yucatan remains intense with cold cloud tops. The transition into nighttime may be a temporary solution to this.



Click on the image to view it as an animated flash loop.
Member Since: Posts: Comments:
Looked outside and seen a green line in the sky now i realize its the old clipper 5 lol...thats the model i'm going with haha :)
Member Since: August 29, 2006 Posts: 22 Comments: 1339
Quoting TropicalAnalystwx13:


What makes you say that?


He's right. It's gone. A new band is developing off of the NE Yucatan, but there is nothing but mid- high-level cloud debris over the center right now.
Member Since: November 24, 2005 Posts: 628 Comments: 26452
Quoting Levi32:


I think those tracks are only possible if Don weakens and falls apart on his journey across the gulf. If it stays a solid tropical storm, then I still think south-central Texas is the target.


What if it becomes a hurricane?
Member Since: July 6, 2010 Posts: 108 Comments: 30237
Quoting yoboi:


old school forcasting they would kick a mule in the azz and see what direction he would run true story


Member Since: Posts: Comments:
T.C.F.W.
04L/TS/D/CX
MARK
22.65N/87.56W


Member Since: July 15, 2006 Posts: 163 Comments: 52096
Heh, sorry guys, but I have to announce that it'll hit Galveston fair and square, but only because I am supposed to move to a new apartment there on Friday and Saturday :-P. It figures that since people think I'm crazy for moving to a town that gets tropical storms, I'll end up moving IN a tropical storm! Hehehe... I'm just hoping that wherever it hits (near or far), somebody who needs it will get the rain.

-Gypsy (generally just a lurker)

P.S. - I also just washed my car.
Member Since: August 21, 2008 Posts: 0 Comments: 8
Quoting MrstormX:


Levi what are your thoughts on the models moving Don towards the TX/LA border?


I think those tracks are only possible if Don weakens and falls apart on his journey across the gulf. If it stays a solid tropical storm, then I still think south-central Texas is the target.
Member Since: November 24, 2005 Posts: 628 Comments: 26452
Quoting atmoaggie:
Can't say I do. The guy I knew that pointed me to a site where I could track it retired 2 years ago. And they changed the website last year.

One would think that a lot more would go into it.

Which one you checking on? GFS?
The link I used to use showed that while GFS is running, the data is being prepared for GFDL and, presumably, HWRF (which run well after GFS, as you well know).


I'm using this site and yes for the GFS. To use HDOB data I would think it would have to be smoothed, to match up with the model resolution. They could be using it in the cyclone models since they have a much higher resolution in the inner nest.
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Quoting MississippiWx:
With the convection waning like it is, this could be where that center reformation comes into play. The NHC mentioned that a center reformation was possible later tonight because of the elongated nature of the center.

Don has really lost any inner core that he had built, though. Going to have to start all over tonight:



What makes you say that?
Member Since: July 6, 2010 Posts: 108 Comments: 30237
Like said in a past post Don is possibly just shedding his thunderstorms to form some stronger thunderstorms, we're gonna have to continue and watch but i still see some intensification in my forecast for the storm
Member Since: July 25, 2011 Posts: 0 Comments: 453
Quoting MiamiHurricanes09:
If that were to occur in the middle of September = apocalypse.

DOOM EVERYONE IS DOOM is what would happen.
Member Since: Posts: Comments:
826. JLPR2
Quoting MississippiWx:
With the convection waning like it is, this could be where that center reformation comes into play. The NHC mentioned that a center reformation was possible later tonight because of the elongated nature of the center.

Don has really lost any inner core that he had built, though. Going to have to start all over tonight:



Needs to pull the convection over the Yucatan into itself.
Member Since: September 4, 2007 Posts: 7 Comments: 8459

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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.