Tropical Depression Two forms from Invest 98L

By: Dr. Jeff Masters , 9:33 PM GMT on July 17, 2011

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Tropical Depression Two (TD2) formed from Invest 98L this afternoon. Hurricane Hunters flew into the suspect area and found a surface circulation north of the Bahamas, with maximum sustained winds of 35 mph. They also determined the system had become warm core—a characteristic that must be present in order to declare a tropical cyclone. Satellite imagery continues to show the system is becoming more organized with a stronger circulation. Wind shear is forecast to remain favorable for the system until Tuesday or Wednesday when higher shear will slide in from the north. Sea surface temperatures are warm enough to sustain a tropical storm.


Figure 1. Satellite imagery of Tropical Depression Two in the Atlantic, east of Florida. This graphic will update to the current satellite imagery.


Figure 2. Official 5-day forecast for Tropical Depression Two. This graphic will remain current.

Forecast for TD2

The models are coming into better agreement as TD2 has become more organized. In terms of dynamical forecast models, the HWRF and GFS both forecast TD2 to max out just above tropical storm strenth. HWRF intensifies TD2 to around 47 mph in the next 24 hours, whereas GFS is a bit slower to bring the system up to tropical storm status. Two statistical models, the DSHP (SHIPS model that includes land interaction) and the LGEM (Logistical Growth Equation Model) both intensify TD2 to a moderate tropical storm over the next 2-3 days.

There tends to be a lot of uncertainty involved with tropical cyclones that form under these circumstances, but our forecast remains in line with the National Hurricane Center and the reliable forecast models. TD2 will move slowly to the northeast in weak steering currents over the next few days before eventually becoming an extratropical storm. There is minimal chance that this system will cross over Florida into the Gulf of Mexico. Timing and path depend heavily on how intense the cyclone gets, as Jeff mentioned in his blog earlier today. A weaker storm will tend to stay south, whereas a stronger storm will grow taller in the atmosphere and winds at higher levels will influence it and steer it northeast.

None of the reliable models predict tropical cyclone development over the remainder of the Atlantic through July 23.

Angela

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IMO Bret is alot more organized than he might appear on Satelite, wouldn't surprise me if he became the first hurricane of the 2011 season.
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Quoting CybrTeddy:


There is several problems,
1) Competing low near by.
2) The convergence is spread out from the trough, this is a lot of the time why trough splits aren't very powerful.
3) dry air to the north intruding.



Yep its pretty sickly looking thing!
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426 CybrTeddy "...Shuttle landing...Would be neat to land at Edwards, given that's where the first one landed too."

Since one of the Shuttles was destined for a California retirement, would have made more sense to schedule a landing at Edwards. If one of the earlier retirees had been forced to land on the WestCoast, then the last one could have landed on the East.
Woulda saved millions in the prep&fuel needed for a piggyback flight from Canaveral to SoCal.
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TS Bret Floater - RGB Color Infrared Loop
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Bret seems to be stationary at the moment
Member Since: May 26, 2011 Posts: 0 Comments: 1193
Again, when does the 00Z nam come out? should be soon? will the 00 models have all the input from the 4 aircract and all their dropsonde's?
Member Since: September 18, 2010 Posts: 0 Comments: 5155
Quoting TampaSpin:



Convergence does matter for anything that is really trying to get going.......LOOK at it. If you have no Convergence at the lower levels.....NO Streghtening can happen at any degree at all!


There is several problems,
1) Competing low near by.
2) The convergence is spread out from the trough, this is a lot of the time why trough splits aren't very powerful.
3) dry air to the north intruding.
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Quoting BahaHurican:
We pretty much need the rain here too.
That rotation was noted in this morning's Tropical Weather Discussion on NHC's website. I was interested to see this because before I even looked at any loops the still imagery of this Twave impressed me.



I think there is now three areas to watch in that area. The wave with the circulation ahead of the second larger wave that is over the Cape Verdes, then a third wave is set to come off Africa over the next couple of days.
Member Since: July 22, 2010 Posts: 6 Comments: 752
Dr. Rick Knabb
It's not pretty on satellite but has been declared a tropical storm, although it's unlikely to significantly affect the U.S. or to become a hurricane.
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Click to enlarge
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Maybe the models are going to pull that circulation NE of Bret to the NE and let Bret do what he is supposed to do, End the drought in S Florida??
Member Since: September 18, 2010 Posts: 0 Comments: 5155
Quoting CybrTeddy:


Convergence and divergence doesn't really mean much for classification. Recon found good solid TS winds in those thunderstorms albeit limited.



Convergence does matter for anything that is really trying to get going.......LOOK at it. If you have no Convergence at the lower levels.....NO Streghtening can happen at any degree at all!
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Ma-on outer bands hitting Japan.
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00z Early Cycle NHC model tracks


BRET
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)





Dynamic Models (More sophisticated models)




Early Model Wind Forecasts



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Is it me or is Bret now going almost do South, with maybe a slight East jog.
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Quoting TampaSpin:



Not sure Brit even deserves its name with so little Convergence........There is nothing at all!


Convergence and divergence doesn't really mean much for classification. Recon found good solid TS winds in those thunderstorms albeit limited.
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Quoting BahaHurican:
Yeah, TS, we know u r going to be right one of these days.... just don't tell us WHEN.... lol

Have u noticed our latest TS?


Ya just got home from being away all day.....about to put the graphics up on the website......more frightened of what and where the next storm might come from!
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Quoting Dirtleg:


Yes...in allll his glory! Pre shower curtain!
Could someone enlighten me about the JFV shower curtain incident, legacy, fetish? Is it what turned him to the darkside? Thanks in advance.
Member Since: May 26, 2011 Posts: 0 Comments: 1193
Quoting Levi32:


Very telling that the competing circulation to the northeast is just as strong as Bret himself.
Only real difference is Bret is more symmetrical... what do u think the impact of that circulation is likely to be?
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Quoting TampaSpin:
OMG a Cat 5 Hurricane is gonna hit south florida...........LOOK OUT!


What? I gotta get my shutters out! LOL
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Not sure Brit even deserves its name with so little Convergence........There is nothing at all!
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Quoting Levi32:


Very telling that the competing circulation to the northeast is just as strong as Bret himself.


It is indeed.
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Quoting weatherxtreme:


LoL and the gulf casters dissappeared too I think...J/k


Nope I'm here but was playing Hot Shots on FaceBook.... LOL Standing by in Lurk mode LOL :o)

Taco :o)
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African strong wave... Does models develop it??
Member Since: August 2, 2010 Posts: 21 Comments: 9730

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Quoting TampaSpin:
OMG a Cat 5 Hurricane is gonna hit south florida...........LOOK OUT!
Yeah, TS, we know u r going to be right one of these days.... just don't tell us WHEN.... lol

Have u noticed our latest TS?
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J/K obviously! Don't see this becoming much a threat to the ConUs! Bermuda might get a little rainmaker tho!
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Quoting ProgressivePulse:


Very telling that the competing circulation to the northeast is just as strong as Bret himself.
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446. xcool
lmaoooo
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OMG a Cat 5 Hurricane is gonna hit south florida...........LOOK OUT!
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...SPECIAL FEATURE...

THE SURFACE LOW LOCATED N OF THE NORTHERN BAHAMAS WAS UPGRADED TO TROPICAL DEPRESSION TWO AT 2100 UTC SUN...AND TO TROPICAL STORM BRET AT 0000 UTC MON...WITH A CURRENT POSITION NEAR 27.5N
78.1W...ABOUT 100 MI...165 KM NW OF GREAT ABACO ISLAND. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. THIS SYSTEM IS PRODUCING AN AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS
FROM 25N-29N BETWEEN 75W-79W...WITH SEAS UP TO 9 FT...INCREASING UP TO 20 FT IN 24 HOURS. BRET IS DRIFTING TOWARD THE SOUTH-SOUTHEAST NEAR 2 MPH...4 KM/H...AND LITTLE MOVEMENT IS EXPECTED OVERNIGHT...FOLLOWED BY A SLOW NORTH-NORTHEASTWARD
MOTION ON MONDAY. PUBLIC ADVISORIES ON BRET ARE ISSUED UNDER WMO HEADER WTNT32 KNHC AND UNDER AWIPS HEADER MIATCPAT2.
FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT22 KNHC AND
UNDER AWIPS HEADER MIATCMAT2.

Significant Wave Height and Peak Direction forecast

Link
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Is it still too early for the 0000Z models? Will they have the input from the 4 aircraft in them?
Member Since: September 18, 2010 Posts: 0 Comments: 5155
Flight two takes off in an hour and forty five minutes.

FLIGHT TWO -- TEAL 71
A. 18/0600
B. AFXXX 0202A CYCLONE
C. 18/0300Z
D. 29.0N 78.5W
E. 18/0500Z TO 18/0900Z
F. SFC TO 10,000 FT
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441. Jax82
Hello Bret, now go away :)
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Quoting avthunder:


We need rain in SoFla! A mild tropical storm would be welcome. Oh well, hope it does not hurt the Bahamas.
We pretty much need the rain here too.
Quoting wolftribe2009:


Yea I am interested to see what happens with this wave? It is very large. The one right behind it also looks to be well organized as well. There also is an area just to the South West of the first wave right off Africa that looked to be to have a bit of cyclonic rotation with it. You can see this area I am talking about in the Central Atlantic sats on NOAA now:

Link
That rotation was noted in this morning's Tropical Weather Discussion on NHC's website. I was interested to see this because before I even looked at any loops the still imagery of this Twave impressed me.

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Quoting presslord:


I remember skippin' class my Junior year of college to watch it land...


Good evening, Press. Nice to be able to hear a first-hand recollection. Thanks, Bud!
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431- Is that a shower curtain alert, beachside?
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Quoting presslord:


I remember skippin' class my Junior year of college to watch it land...


Wish I could have been around for that, wasn't born until couple years later.
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Quoting CybrTeddy:
Said about 8 hours ago then-98L would look like this, its to be expected. Though, not going to lie I wasn't expecting Bret this soon.
Agreed. Was kinda expecting it myself. It's enough to make me get up at 2 a.m..... lol
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Quoting JRRP:

is JVF


Yes...in allll his glory! Pre shower curtain!
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Quoting coastaltugcaptain:
I am on a tug heading south to Ft. Lauderdale with an 80,000 barrel oil barge. I am keeping an eye on this as well. I currently have a steady 6’ swell out of the ENE and winds of 15 – 20 knots also out of the ENE. Just thought I would give you some local observations while I am here. Expect to be off Cape Canaveral at 0600 on the 18th and Ft. Lauderdale around 0700 on the 19th.

Time: 1950
Position: 29 30.08 N 81 03.08 W
4 nm East of Flagler Beach, FL.
Course: 156 True
Speed: 6.6 Knots


Thanks 4 the info, capt'n... I'm too far south to be able to observe more than clouds from potential feeder bands...

Quoting weathermanwannabe:


I cannot second guess the call from NHC, as I am sure they had data this afternoon to call a tropical storm based on wind speeds, but looking at this rapid deterioration at the moment, I am thinking we just wasted a "name" on this one...........
Don't agree this is a name waste. I was expecting this deterioration overnight until Dmax, and thus wasn't expecting a name to be applied before the a.m., but I still think it would have ended up as Bret. Don't be surprised if it's got a much more pc TC appearance in the morning.

Quoting sunlinepr:
Contrary to Previous waves from Africa, this one looks that has enough convection to hold together





We've been saying that since it popped off this a.m. sometime... lol... the timing also seems right for the end of the month....
Quoting MrstormX:
I'm starting to think the Bahamas might get a landfall if this goes any farther South.
It's already close enough to qualify as a "brush". I was thinking the last time we had a storm dropping south like this was... Hanna? 2008? Kept going until it hit Haiti before it went north again.

Quoting MrstormX:
Anybody else wondering why there is no TS Warning in the Bahamas, it seriously looks like it might scrape a landfall there.
Warnings went up at 5 p.m.
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Quoting CybrTeddy:


I aint Pat, but Shuttle landing is just before 6 am on Thursday at KSC. If Bret still around, which I don't think it will, landing will be waved off until they either land at Edwards AFB or Bret clears the next day. Would be neat to land at Edwards, given that's where the first one landed too.


I remember skippin' class my Junior year of college to watch it land...
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431. JRRP
Quoting Dirtleg:

We have Janiel on the beach for updates!!!



is JVF
Member Since: August 16, 2007 Posts: 0 Comments: 5482
Quoting brendanjames:
yah know, none of the models called this, so no one thought it would form. now the models point it off to the northeast. but most satellite show steering towards the west. definitely very interesting.

ive been watching this system since it was just a little swirl off SC. absolutely fascinating.


Bret is actually moving to the SSE away from the FL coast. Where will it go after that will depend on how strong it is and how far south the ridge is. So far I don't see why it would not follow the NHC official track so Bret so far is Fish Storm. They should have named it different Bret Farve will prove to be a hard TS to predict. It will change its mind constantly.
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Quoting neutralenso:

Bingo you hit it. its that wave from africa


Yea I am interested to see what happens with this wave? It is very large. The one right behind it also looks to be well organized as well. There also is an area just to the South West of the first wave right off Africa that looked to be to have a bit of cyclonic rotation with it. You can see this area I am talking about in the Central Atlantic sats on NOAA now:

Link
Member Since: July 22, 2010 Posts: 6 Comments: 752
Quoting VirgilSolozzo:
What you're seeing is the higher level convection getting sheared east. The LLC is meandering.



Yeah, looking closer the LLC stayed in position. Interesting though to see the impact on the clouds in the western semi though.
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GULF OF MEXICO...
THE REMNANTS OF A TROPICAL WAVE...NOW INLAND OVER MEXICO... CONTINUE TO GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER THE WESTERN GULF AND BAY OF CAMPECHE S OF 24N W OF 94W. SIMILAR ACTIVITY REMAINS OVER THE COASTAL WATERS OF LOUISIANA...MISSISSIPPI...ALABAMA...AND THE FLORIDA PANHANDLE N OF 26N BETWEEN 84W-92W. THIS AREA OF CONVECTION IS ASSOCIATED TO A BROAD AREA OF MID-UPPER LEVEL CYCLONIC FLOW CENTERED OVER SOUTHERN MISSISSIPPI. THE REMAINDER OF THE GULF IS UNDER THE
INFLUENCE OF A WEAK SURFACE RIDGE KEEPING FAIR WEATHER CONDITIONS ACROSS THE AREA.


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Quoting presslord:
If Pat is around...When is the shuttle due to land? and...What might this mean to the prospects?


I aint Pat, but Shuttle landing is just before 6 am on Thursday at KSC. If Bret still around, which I don't think it will, landing will be waved off until they either land at Edwards AFB or Bret clears the next day. Would be neat to land at Edwards, given that's where the first one landed too.
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Quoting Skyepony:


July 21st


Thanks!
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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.

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