Tropical Depression Two forms from Invest 98L

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

Share this Blog
0
+

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

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: 175 - 125

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 | 25Blog Index

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.
Member Since: Posts: Comments:
Ciao for now...

Member Since: Posts: Comments:
No problem swirl...

weatherxtreme ITS 93L from june....
i though 98L was going to pull the same thing 93L did, vincent
Member Since: Posts: Comments:
Quoting caneswatch:
I do know the NHC has their "bad" moments, and I think this track is going to be one of them. There's absolutely no way that Bret is going NE with those very weak steering currents. It's going to continue to head south, and there will be TS Warnings for the Bahamas, and I won't be surprised if there's a TS Warning for some of Florida too.
There are already warnings for the Bahamas, canes. Northern Abaco actually is currently in the area of high TS winds potential right now, and most of the rest of the northern Bahamas is somewhere in the zone. I'd not be surprised to see the centre drift as far south as mainland Abaco before it takes off to the NE, either. I do think it's headed that way, but I don't think it'll happen for about 24 hours.
Member Since: October 25, 2005 Posts: 19 Comments: 20742
Quoting GeoffreyWPB:
Miami NWS Discussion

ALTHOUGH THE BROAD LOW CURRENTLY HAS LITTLE MOVEMENT...THE
GUIDANCE CONTINUES TO INDICATE A SLOW EASTWARD TO NORTHEASTWARD
DRIFT BEGINNING ON MONDAY...BUT THERE IS STILL A LOT OF UNCERTAINTY
IN THE MOVEMENT OF THIS BROAD LOW...WILL HAVE TO MONITOR IT CLOSELY.
Member Since: Posts: Comments:
170. JLPR2
You guys remember 94E right? XD

1. A VIGOROUS LOW PRESSURE SYSTEM LOCATED ABOUT 225 MILES SOUTH OF
EL SALVADOR IS PRODUCING WIDESPREAD CLOUDINESS AND SCATTERED
THUNDERSTORMS. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR FURTHER
DEVELOPMENT OF THIS LARGE DISTURBANCE AS IT MOVES WEST-NORTHWESTWARD
AT 5 TO 10 MPH. THIS SYSTEM HAS A MEDIUM CHANCE...40 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
Member Since: Posts: Comments:
Quoting Vincent4989:

Hint: tiny speedy blob that got to 30% before it made landfall


Ahh, got it LoL
Member Since: Posts: Comments:
Quoting HurricaneDean07:
hurricaneswirl that's my forecast for the winds IMO.

Recon bound for home after successful day


Oh I thought you were predicting what the NHC was gonna predict XD
Member Since: Posts: Comments:
T.C.F.W.
02L/TS/B/CX
MARK
27.77N/77.67W
Member Since: Posts: Comments:
Quoting weatherxtreme:


??

Hint: tiny speedy blob that got to 30% before it made landfall
Member Since: November 13, 2009 Posts: 2 Comments: 728
hurricaneswirl that's my forecast for the winds IMO.

Recon bound for home after successful day
Member Since: Posts: Comments:
Quoting angelafritz:
To illustrate the usefulness of an ensemble prediction system, a few of the ensemble members from various models (mostly ECMWF) were playing around with this notion for the past week or so, ever since the boundary was forecast to drop into favorable warm waters. So although deterministic runs were ruling it out, the models, in a grander sense, were forecasting a low probability of this event to actually occur. And it is a low prob event - not very many of these tropical transitions actually come to fruition. Which is why it takes everyone by surprise! :)

Hey, kewl that u have ur own id for the blog.... I agree with the model ensembles... we've talked some here last year about how something will show in GFS long range, to give an example, say 10 days out, then disappear in the shorter range forecasts. Sure enough, around 10 days later, we get something in the area, even the the short range forecast may still be saying nada. IIRC, pple were pointing to NAM and CMC, which seem to do well with these types of systems because they are generally better at baroclinic stuff. [I have no problem being corrected if I'm wrong on the baroclinic stuff... lol]
Member Since: October 25, 2005 Posts: 19 Comments: 20742
Quoting CybrTeddy:


Well Taz, it isn't. This is the last mission of the Space Shuttle.


I know a Florida landing is very important for the KSC employees on an emotional level so it does matter to some.
Member Since: Posts: Comments:
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*
Member Since: Posts: Comments:
Quoting Vincent4989:
Pre-Bret looks like the failed invest that preceded the huge but failed invest.


??
Member Since: Posts: Comments:
Hurricane Hunters are now ascending and leaving what will soon be Tropical Storm Bret.

I'm in firm belief that Florida should keep a watchful eye on this storm.
Member Since: Posts: Comments:
Quoting HurricaneDean07:
Next Advisory Prediction:
Advisory 1A:
45 Mph
27.1 N ; 78.0 W
Moving South at 3mph
1009 MB

Forecast Strength:
3 hours: 55 mph ; Hurricane chance: 18%
6 hours: 60 mph ; Hurricane Chance: 28%
9 hours: 60 mph ; Hurricane chance: 26%
12 hours: 60 mph ; Hurricane Chance: 25%
18 hours: 65 mph ; Hurricane Chance: 32%
24 hours: 65 mph ; Hurricane Chance: 32%
30 hours: 65 mph ; Hurricane Chance: 34%
36 hours: 70 mph ; Hurricane Chance: 39%
42 hours: 70 mph ; Hurricane Chance: 40%
48 hours: 70 mph ; Hurricane chance: 45%(Peak)
54 hours: 65 mph ; Hurricane chance: 31%
60 hours: 60 mph ; Hurricane chance: 20%
72 hours: 50 mph ; Hurricane chance: 12%
84 hours: 40 mph ; Hurricane chance: 1%(post-tropical)


The strength and movement is reasonable, but the NHC doesn't change their forecast part during Intermediate Advisories.
Member Since: Posts: Comments:
Quoting neutralenso:

Levi your saying there is a very small possiblity for this to move westward right? and also in one of your tidibts when you talked about the pattern setting up dangerous for the US, did you mention it was going to change in July because right now the US once again has dodged 2 bullets


Just because a pattern is in place doesn't mean storms can't dodge it. High pressure is constantly shifting, and during these shifts storm can break from the pattern that is in place when they are in not in transition.
Member Since: Posts: Comments:
Typhoon Ma-on has finally made the long predicted turn from heading Northwest to NorthNorthwest along with the accompanying slowing of travel-speed down to 10mph(16.1k/h)

The curvature of the turn is much tighter than predicted 24hours ago, and Ma-on is now expected to miss landfall on the Japanese coastline.
Copy&paste 20.8n139.6e, 21.1n138.7e, 21.1n137.9e, 21.8n137.1e, 22.7n136.3e-23.4n135.6e, 23.4n135.6e-24.4n134.6e, 24.4n134.6e-25.2n133.8e, 25.2n133.8e-26.0n133.4e, koj, hnd, sdj into the GreatCircleMapper for more information about the most recently reported 24hours
Member Since: August 21, 2007 Posts: 0 Comments: 4860
The big picture...

Member Since: Posts: Comments:
Next Advisory Prediction:
Advisory 1A:
45 Mph
27.1 N ; 78.0 W
Moving South at 3mph
1009 MB

Forecast Strength:
3 hours: 55 mph ; Hurricane chance: 18%
6 hours: 60 mph ; Hurricane Chance: 28%
9 hours: 60 mph ; Hurricane chance: 26%
12 hours: 60 mph ; Hurricane Chance: 25%
18 hours: 65 mph ; Hurricane Chance: 32%
24 hours: 65 mph ; Hurricane Chance: 32%
30 hours: 65 mph ; Hurricane Chance: 34%
36 hours: 70 mph ; Hurricane Chance: 39%
42 hours: 70 mph ; Hurricane Chance: 40%
48 hours: 70 mph ; Hurricane chance: 45%(Peak)
54 hours: 65 mph ; Hurricane chance: 31%
60 hours: 60 mph ; Hurricane chance: 20%
72 hours: 50 mph ; Hurricane chance: 12%
84 hours: 40 mph ; Hurricane chance: 1%(post-tropical)
Member Since: Posts: Comments:
Pre-Bret looks like the failed invest that preceded the huge but failed invest.
Member Since: November 13, 2009 Posts: 2 Comments: 728
All of this being said, the process of TD 2 moving around will be very slow during the next day or two. It will be around our back yard for a while and should be watched carefully.
Member Since: Posts: Comments:
Quoting ncstorm:
I just want to state for the record that I called this storm every since last week..toot!! yeah, I'm tooting my own horn..I said TS for tomorrow morning but it seems to want to intensify quicker which is now scary because it hasnt even had DMAX yet..However as I said this morning, I can see this becoming a hurricane and I still believe that..remember, Dr. Masters said, the stronger it gets, the more northward it will go
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.
Member Since: October 25, 2005 Posts: 19 Comments: 20742
If we monitor it any closer someone might get bumped in da head with a sonde.



: )
Member Since: Posts: Comments:
Quoting TxHurricanedude11:
vortex says ts


Gotta expect a TS upgrade at 8pm, or 11pm latest.
Member Since: Posts: Comments:
Quoting cchsweatherman:


Something that I'm keeping in mind is that the computer models always tend to overestimate troughs and underestimate ridges. Just in analyzing water vapor imagery and the upper level pattern, this is a rather weak, very low amplitude shortwave trough and I doubt its gonna have much influence on the storm.


Not all models do that. The GFS and CMC tend to overestimate troughs. The ECMWF and sometimes the NOGAPS tend to overestimate ridges, but both take TD 2 northeast.
Member Since: Posts: Comments:
Miami NWS Discussion

ALTHOUGH THE BROAD LOW CURRENTLY HAS LITTLE MOVEMENT...THE
GUIDANCE CONTINUES TO INDICATE A SLOW EASTWARD TO NORTHEASTWARD
DRIFT BEGINNING ON MONDAY...BUT THERE IS STILL A LOT OF UNCERTAINTY
IN THE MOVEMENT OF THIS BROAD LOW...WILL HAVE TO MONITOR IT CLOSELY.
Member Since: Posts: Comments:
AL 02 Rainbow

Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting Levi32:


The ridge is pretty close to that tipping-point, between wanting to drag TD 2 westward and push it eastward. The straw that breaks the camel's back will likely be the shortwave trough currently over Southern Canada that will be moving out over the NW Atlantic during the next couple days, re-developing the weakness to the northeast that will tug on TD 2. Once it starts moving towards the weakness, the ridge will just help push it in that direction.


Something that I'm keeping in mind is that the computer models always tend to overestimate troughs and underestimate ridges. Just in analyzing water vapor imagery and the upper level pattern, this is a rather weak, very low amplitude shortwave trough and I doubt its gonna have much influence on the storm.
Member Since: Posts: Comments:
Quoting BahaHurican:
Google Earth tells me that the 5 p.m. position of TD2 is only 20 miles away from Grand Cay, the nearest Abaconian cay of note... and it's drifting S at 2mph. I really think the "fish" designation is moot at this point, though I do admit this is not the usual angle from which a storm normally approaches Grand Cay... lol



To be expected w/ Dmin in effect. Expect storms to rebuild around 2 a.m.


No upgrade, yet, right? Prolly happen at 5 a.m., unless Dmax has less of an effect than I'd expect...


Stay safe down there!
Member Since: August 19, 2006 Posts: 13 Comments: 13481
BTW, all the pple thanking the doc should also thank Angela... better get on her good side so when the doc is on vacation she will still love us enough to give us the 2 updates a day we may actually need in early August.... lol
Member Since: October 25, 2005 Posts: 19 Comments: 20742
Notice that TD #2 is already directly south of the very eastern-most edge of the U.S. ridge, or even slightly east of there. This is not a very favorable situation for the ridge to nose in and bring TD 2 westward. The ridge is also more circular than elongated, which makes it hard for a long "nose" to develop to the north of TD 2. With the trough not really leaving the western Atlantic, and soon to get reinforced by a new shortwave, it is likely that the NE tug will win out and take TD 2 out to sea.

Member Since: Posts: Comments:
Quoting Levi32:


The ridge is pretty close to that tipping-point, between wanting to drag TD 2 westward and push it eastward. The straw that breaks the camel's back will likely be the shortwave trough currently over Southern Canada that will be moving out over the NW Atlantic during the next couple days, re-developing the weakness to the northeast that will tug on TD 2. Once it starts moving towards the weakness, the ridge will just help push it in that direction.


Thanks. I think it will depend on exactly how strong the ridge is. I'm looking at the 500mb heights on the GFS and it shows the shortwave grabbing Bret in a few days. But if the subtropical ridge becomes stronger than forecast it could block the shortwave from penetrating far enough south, right?
Member Since: Posts: Comments:
Google Earth tells me that the 5 p.m. position of TD2 is only 20 miles away from Grand Cay, the nearest Abaconian cay of note... and it's drifting S at 2mph. I really think the "fish" designation is moot at this point, though I do admit this is not the usual angle from which a storm normally approaches Grand Cay... lol



Quoting hurricanehunter27:
Thunderstorms need to re fire, starting to look a little ragged.

To be expected w/ Dmin in effect. Expect storms to rebuild around 2 a.m.


No upgrade, yet, right? Prolly happen at 5 a.m., unless Dmax has less of an effect than I'd expect...
Member Since: October 25, 2005 Posts: 19 Comments: 20742
....caster's beau-coup,cher
Member Since: Posts: Comments:
Quoting TxHurricanedude11:
Gotta love people with ignorant posts like bye bye td 2...relax it just formed and you all fall for the track and say "fish" i just dont see this being a fish right now!



Is not an ignorant post because I'm based on what the NHC said about the track.
Member Since: Posts: Comments:
HPC Discussion on the shortwave..
If I am understanding correctly, it dosen't look there is agreement on it?

WHILE FARTHER EWD A LEADING SHORTWAVE SHOULD TRACK
FROM THE NRN ROCKIES ACROSS SRN CANADA DURING WED-FRI. WHILE
RECENT GFS RUNS BEFORE THE 00Z VERSION SET UP THE ERN PAC MEAN
TROF EWD OF THE CURRENT CONSENSUS THAT INCLUDES THE 00Z
GFS...RECENT OPERATIONAL ECMWF RUNS HAVE BEEN PARTICULARLY ERRATIC
WITH THE 00Z RUN ESTABLISHING THE ERN PAC TROF WWD OF CONSENSUS
WHILE THE 12Z/16 ECMWF WAS TO THE EAST OF CONSENSUS.
THE
CANADIAN/NOGAPS MAY BE A LITTLE EXTREME...BUT AT LEAST THEIR ERN
PAC TROF POSITIONS ARE NOT FAR FROM THE 12Z ECMWF FROM YESTERDAY
AND THE 00Z GFS/CANADIAN ENSEMBLE MEANS. QUESTIONABLE ECMWF
EVOLUTIONS OVER THE PACIFIC LEAD TO DOWNSTREAM FEATURES TRENDING
OUT OF PHASE WITH CONSENSUS AS WELL.
Member Since: August 19, 2006 Posts: 13 Comments: 13481
Quoting MiamiHurricanes09:
000
URNT12 KNHC 172204
VORTEX DATA MESSAGE AL982011
A. 17/21:51:20Z
B. 27 deg 32 min N
078 deg 01 min W
C. NA
D. 35 kt

E. 137 deg 29 nm
F. 164 deg 36 kt
G. 137 deg 29 nm
H. EXTRAP 1009 mb

I. 20 C / 214 m
J. 24 C / 213 m
K. 23 C / NA
L. NA
M. NA
N. 1234 / 01
O. 0.02 / 0 nm
P. AF304 01BBA INVEST OB 19
MAX OUTBOUND AND MAX FL WIND 44 KT NW QUAD 21:55:00Z
SLP EXTRAP FROM BELOW 1500 FT
;



i say we have a TS
Member Since: May 21, 2006 Posts: 5089 Comments: 114072
Starting to get some decent storms trying to wrap around the center
Member Since: August 7, 2010 Posts: 0 Comments: 1933
000
URNT12 KNHC 172204
VORTEX DATA MESSAGE AL982011
A. 17/21:51:20Z
B. 27 deg 32 min N
078 deg 01 min W
C. NA
D. 35 kt

E. 137 deg 29 nm
F. 164 deg 36 kt
G. 137 deg 29 nm
H. EXTRAP 1009 mb

I. 20 C / 214 m
J. 24 C / 213 m
K. 23 C / NA
L. NA
M. NA
N. 1234 / 01
O. 0.02 / 0 nm
P. AF304 01BBA INVEST OB 19
MAX OUTBOUND AND MAX FL WIND 44 KT NW QUAD 21:55:00Z
SLP EXTRAP FROM BELOW 1500 FT
;
Member Since: Posts: Comments:
Quoting PcolaDan:


I have all the answers!


(99% incorrect though when it comes to weather)
Then I know who to ask from now on! lol
Member Since: Posts: Comments:

Viewing: 175 - 125

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 | 25Blog 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.