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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Quoting SugaCane:


Does anyone think it is possible for TD2/Bret to be pulled under that ridge despite model consensus being against that solution?


In a situation like this, the possibility cannot be discounted, however, an escape to the northeast seems more likely. It should be monitored closely just in case, though.
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Quoting neutralenso:

haha image wont load what does it show?
Check the link.


Quoting ackee:
which area of the carrib and us are most at risk now base on where high is right now
Well, I've learned to watch that 1016 line. That's usually the hardest edge of the high that lows will "roll" along... more or less. IOW, if u have the 1014 line running through your part of the Car, Atl, or GoM, u've got a hurricane highway.... of course nothing is written in stone when it comes to 'canes, and stronger systems can have lots of influence on any weakness in that controlling high. The other thing I look at is the strength of the high at its centre, because from my experience how strong the high is to begin with can also impact how quickly a recurvature can happen.

To sum up: with this current high so strong over the Azores, we're much more likely to see whatever rolls off AFrica get closer to our area of the MDR. Then whatever happens depends on where the edge of the high is, what weaknesses - troughs, other low pressure systems - are impacting the high. It's all pretty fluid.
Member Since: October 25, 2005 Posts: 19 Comments: 20730
218....dear Lord: please don't let me say what I'm thinkin'
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ATCF Imagery Portal 98L
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Does anyone think it is possible for TD2/Bret to be pulled under that ridge despite model consensus being against that solution?
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I like Lixion Avila,,he has moxie..
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98L has a blinker on, but will it Bob, den weave ?


Hmmm, hmmmmm,..?
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Possible decoupling of TD 2's surface center may be underway as it drifts SSW with the current surface flow, while the thunderstorms and the mid-level circulation drift eastward.

GOES-13 Rapid-scan visible loop of TD 2
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Quoting pbeachbaby:
ok, just a question if somebody doesn't mind please.
at a earlier model I saw, it showed TD2 looking like it was going into GOM then up thru the panhandle, what changed so quickly ? was it the Hurricane Hunters ?


ok, really, sorry that was kinda mean of me.

The models did not have a GOOD starting point yesterday, last night, early today. The models are just computer runs, ok? I mean they are good, but they are only math, expressed visually.
As more accurate info becomes available (yes, from recon aka TheHurricaneHunters), then the MATH going into the computer gets better, and the results become more accurate.

Very simplified, yes.
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214. 7544
lots of red over so fl is this from td2 ?
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Quoting Guaricandilla2011:


That's a Cuban word, ROFL!!!!!!!!!!!!!
Pardon me Doctor. I was thinking of Dr Guarry Candilla, the Argentinian whiz kid. Here, have a cigar.
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We need the Funktop to really Rally..

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123 JLPR2 "Could TD2/Bret have a little Fujiwara effect with the spin to its NW?"

Nothing classically Fujiwhara. TD2's spin is more likely to catch the much closer and heavier mass of convection to its ENE; shoving TD2 southward and possibly slightly westward in the short term, instead of immediately following those clouds out to fish heaven.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
earlier,

18z Early Cycle NHC model tracks
TD #2
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)
Dynamic Models (More sophisticated models)




Dynamic Models (More sophisticated models)




Early Model Wind Forecasts

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The hurricane hunters wind map almost looks like it is showing two COCs. Or am I reading it wrong?
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sigh...

Yes, the Hurricane Hunters re-aimed the storm in a different direction. We're just not ready to have a storm hit the east coast of Florida yet.

Hurricane Hunters are cool like that.
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TD2 definitely going to hit NOLA as a cat 5...RUN!!!

ha! thought i'd make my first post of the year with a bang. seriously, though, it would be nice if brett would come and put out the wildfires burning down east in NC. tired of breathing that smoke.
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Is Pre-Bret gonna be able to suck in that moisture blowin up over Florida? Just askin...
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Bermuda could be in play for Bret, if it goes that direction.
Member Since: May 27, 2009 Posts: 0 Comments: 4355
AL 02


Dvorak

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ok, just a question if somebody doesn't mind please.
at a earlier model I saw, it showed TD2 looking like it was going into GOM then up thru the panhandle, what changed so quickly ? was it the Hurricane Hunters ?
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198. JLPR2
Quoting aquak9:


I'm in charge of the ducks!


Aye Boss. :P
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I think at this point the most important thing to keep in mind here is this line from Angela's OP. There tends to be a lot of uncertainty involved with tropical cyclones that form under these circumstances
.
.
.
.

I look at this cyclone as the tail on the end of a rattlesnake. The rattlesnake in this case being the trough running SW to NE. I get nervous when we have a meandering cyclone stewing in the area this storm is in. The current NHC track and intensity looks most probable, but the tail could detach, or the cyclone may meander long enough for the steering to change, and possibly change again. This one bears watching as they all do, but maybe watch this one closer.
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Quoting wolftribe2009:


The GFS showed the low forming almost a week ago. It was showing the low a good 120 hours before it formed just a bit further north than it is.


and the NAM and ECWMF..
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Quoting BahaHurican:
All right, I did give u ur props on the last blog.... lol.... though I though u were expecting it to develop closer to the GA / SC border than where it did actually pop up. Good on you... u beat out the models AND NHC.... I agree with u on the TS in the a.m. [prolly early] since I think Dmax is not going to be particularly kind to it...

I want to see what NHC will say about it at 8 p.m.


LOL..I had to toot..
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Quoting HurricaneDean07:
jason its not out of the question, remember two more dmax's.... though i get why you mention it....
that's my "out there" forecast, my safer forecast would be...
65 mph, and 27% chance of a hurricane out of bret...
dont get why all of you ppl are saying a weak TS... you guys said the same thing with Arlene, and what happened? a 65 Mph storm that if had an extra 6 to 10 hours of time over water wouldve likely been a hurricane.


If it stays weak than we are going to have a huge problem. It will miss the ride out and head more westward. Than everything changes. My intensity forecast is for a storm 50-60 MPH. It is the track that I am unsure on. I even think this could become a minimal hurricane or that just might be the fact that I like the name "Hurricane Bret"
Member Since: July 22, 2010 Posts: 6 Comments: 752
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Why is everybody picking on Dr Guaricandilla? Don't any of you know he is one of Argentina's foremost Theorists?
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Quoting TxHurricanedude11:

ok ok sorry about that nevermind


apology accepted
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189. ackee
Quoting BahaHurican:
Pple interested in the high setup might want check this out...


which area of the carrib and us are most at risk now base on where high is right now
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Quoting CybrTeddy:


No models developed TD2.


The GFS showed the low forming almost a week ago. It was showing the low a good 120 hours before it formed just a bit further north than it is.
Member Since: July 22, 2010 Posts: 6 Comments: 752
jason its not out of the question, remember two more dmax's.... though i get why you mention it....
that's my "out there" forecast, my safer forecast would be...
65 mph, and 27% chance of a hurricane out of bret...
dont get why all of you ppl are saying a weak TS... you guys said the same thing with Arlene, and what happened? a 65 Mph storm that if had an extra 6 to 10 hours of time over water wouldve likely been a hurricane.
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Quoting JLPR2:


Yeah, we know, the Caribbean is a sitting duck for CV systems. -_-


I'm in charge of the ducks!
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Well it looks like all the "nay" sayers will be eating crow. Where is the weather channel's Doctor Knabbs now? I had said in my blog almost a week ago that this area would be our next main concern.

I also am leaning on it not going north east. I think it will remain too weak and move more west or north west towards the carolinas. It might even mouth south and than west.
Member Since: July 22, 2010 Posts: 6 Comments: 752
Quoting muddertracker:
Levi, what's going on with that mess off the coast of LA? Is there any chance tht gets out into the water and does something..like move west and bring Texas some precip? *wishing really hard*


There is a small disturbance there at the very tail-end of the old front that TD 2 is attached to. This is what is generating those showers. It is on the south side of the big ridge, and thus should drift westward in the direction of Texas, hopefully destabilizing the atmosphere for you guys. Some weak showers are already propagating westward into eastern Texas.



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Quoting neutralenso:

haha image wont load what does it show?




its onthe blog lol
Member Since: May 21, 2006 Posts: 5089 Comments: 114054
Quoting Cotillion:
Any models pick up on this in the days before?

Quite a contrast to Arlene's sizeable circulation, TD2/soon to be Bret looks pretty tiny.


No models developed TD2.
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Quoting weatherxtreme:
It has cleared up here in NE Florida this afternoon/evening. Sun is out with some clouds and some heavy breeze but nice! I guess we may be in the clear now at this point according to models. Bret eventually heads to sea as it appears although a little hard to believe.


may I ask where in NE Fla you are? I'm three miles inland from JaxBeach. And it IS a gorgeous evening, eyeshadow-blue skies and a great breeze.
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179. JLPR2
Quoting BahaHurican:
Pple interested in the high setup might want check this out...




Yeah, we know, the Caribbean is a sitting duck for CV systems. -_-
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Pple interested in the high setup might want check this out...


Member Since: October 25, 2005 Posts: 19 Comments: 20730
Any models pick up on this in the days before?

Quite a contrast to Arlene's sizeable circulation, TD2/soon to be Bret looks pretty tiny.
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It has cleared up here in NE Florida this afternoon/evening. Sun is out with some clouds and some heavy breeze but nice! I guess we may be in the clear now at this point according to models. Bret eventually heads to sea as it appears although a little hard to believe.
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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.