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 CybrTeddy:


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




that part is ture is the last one would be nic too see it land in CA for one last time not too be rude too FL
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123. JLPR2
Question here.

Could TD2/Bret have a little Fujiwara effect with the spin to its NW?
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Quoting Tazmanian:



thats not nic too say


Well Taz, it isn't. This is the last mission of the Space Shuttle.
Member Since: July 8, 2005 Posts: 259 Comments: 24553
Quoting Guaricandilla2011:
Patrick, thank you for all of your updates, they're appreciated it. Do not think that they go unseen, =).
Wipe the brown stuff off of your nose, you are wasting everybody's time and good blog space.
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T.C.F.W.
02L/TD/B/CX
MARK
27.77N/77.67W
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Quoting caneswatch:


What's your opinion on Bret, Geoff?


I agree with the NHC. We may see some stronger winds and perhaps an increase in precip., but I do think it will eventually veer off the northeast. It looks like it is entraining a lot of dry air on its west side.
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Quoting TaylorSelseth:


Thanks Levi!

Why do you think the ridge is too far south to drag Bret westward? Maybe my noobishness is showing, but it looks like just the right place for it to drag Bret south of it.


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.
Member Since: November 24, 2005 Posts: 635 Comments: 26699
see ya, bye bye TD#2
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Quoting bluenosedave:


Not at Kennedy, so they'll land at Edwards. I mean, it hardly matters anymore, right? She's not going up again.



thats not nic too say
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BTW the Shuttle lands on Thursday, so I doubt Bret by then will have an affect.
Member Since: July 8, 2005 Posts: 259 Comments: 24553
Well said and done, Thank You Levi
Quoting Levi32:
Good afternoon.

Blog update:

Special Tropical Tidbit for Sunday, July 17th, with Video
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Convection beginning to build over the circulation.
Member Since: July 8, 2005 Posts: 259 Comments: 24553
No reliable models predicted this. But lets jump on the models now.
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Quoting Tazmanian:
with TD 2 no shutted landing this week


Not at Kennedy, so they'll land at Edwards. I mean, it hardly matters anymore, right? She's not going up again.
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Hey guys, what's the tiny blob doing?
Member Since: November 13, 2009 Posts: 2 Comments: 728
Quoting scooster67:

Excellent explanation, as always.

Thanks Levi


Thank you.
Member Since: November 24, 2005 Posts: 635 Comments: 26699
Quoting Levi32:
Good afternoon.

Blog update:

Special Tropical Tidbit for Sunday, July 17th, with Video


Thanks Levi!

Why do you think the ridge is too far south to drag Bret westward? Maybe my noobishness is showing, but it looks like just the right place for it to drag Bret south of it.
Member Since: August 29, 2008 Posts: 0 Comments: 324
If Bret is gonna go NE why is the system near Mobile still plowing westbound, wouldn't that turn NE first before Bret?! And Bret is farther south than the system along the gulf coast. So somebody is jerking around at the expert desk
Member Since: July 14, 2008 Posts: 2 Comments: 9680
102. ackee
Quoting masonsnana:
A discussion includes questions and answers. Some of us do not have all the answers.
THANKS FRAKLY I think question brings this blog alive show the variety of opinion on this blog
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Quoting GeoffreyWPB:


What's your opinion on Bret, Geoff?
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Quoting stormpetrol:
Time: 20:46:30Z
Coordinates: 27.7833N 77.85W
Acft. Static Air Press: 991.8 mb (~ 29.29 inHg)
Acft. Geopotential Hgt: 185 meters (~ 607 feet)
Extrap. Sfc. Press: 1013.6 mb (~ 29.93 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 60° at 36 knots (From the ENE at ~ 41.4 mph)
Air Temp: 18.0°C (~ 64.4°F)
Dew Pt: 17.3°C (~ 63.1°F)
Peak (10s) Flt. Lvl. Wind: 41 knots (~ 47.1 mph)
SFMR Peak (10s) Sfc. Wind: 54 knots (~ 62.1 mph)
SFMR Rain Rate: 51 mm/hr (~ 2.01 in/hr)
(*) Denotes suspect data

WOW!! no suspect data in this reading



Except for the RR's of 2"/hr
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Quoting masonsnana:
A discussion includes questions and answers. Some of us do not have all the answers.


I have all the answers!


(99% incorrect though when it comes to weather)
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Quoting scCane:
I'd give them an A. Right now this thing doesn't really look that great on the visible due to shear and D-min, it needs far more deep convection before it can be upgraded to a TS.
Shear?
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Quoting cchsweatherman:
Some very intense thunderstorms building over the Northern Bahamas. Definitely trying to strengthen further and will help in lowering pressures.


Thunderstorm activity remains quite weak for the moment. Intense would be -70C or colder cloud tops (red colors)

Member Since: November 24, 2005 Posts: 635 Comments: 26699
personally from the data I've seen, I think this a 45-50mph TS, but I'm not an an expert so I don't know, it's just my layman opinion
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Quoting RitaEvac:
KOTG, don't remember you saying anything about it
thats right cause iam a tracker been tracking it since yesterday first to issue T.C.F.A. this am as well and first to declared td right after and now i will be first to declare TS bret as well

but nope i did not say nothing AT ALL
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02L has moved towards the ENE in between the vortex message released at 21:08 UTC and the latest center fix that took place around 8 minutes ago.
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Quoting Levi32:
Good afternoon.

Blog update:

Special Tropical Tidbit for Sunday, July 17th, with Video

Excellent explanation, as always.

Thanks Levi
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Some very intense thunderstorms building over the Northern Bahamas. Definitely trying to strengthen further and will help in lowering pressures.
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Time: 20:46:30Z
Coordinates: 27.7833N 77.85W
Acft. Static Air Press: 991.8 mb (~ 29.29 inHg)
Acft. Geopotential Hgt: 185 meters (~ 607 feet)
Extrap. Sfc. Press: 1013.6 mb (~ 29.93 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 60° at 36 knots (From the ENE at ~ 41.4 mph)
Air Temp: 18.0°C (~ 64.4°F)
Dew Pt: 17.3°C (~ 63.1°F)
Peak (10s) Flt. Lvl. Wind: 41 knots (~ 47.1 mph)
SFMR Peak (10s) Sfc. Wind: 54 knots (~ 62.1 mph)
SFMR Rain Rate: 51 mm/hr (~ 2.01 in/hr)
(*) Denotes suspect data

WOW!! no suspect data in this reading
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Quoting KEEPEROFTHEGATE:
i want a rating as well how did i do forecasting the system


A+
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Quoting masonsnana:
A discussion includes questions and answers. Some of us do not have all the answers.
+1 LOL.
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Anytime I see storms over water hanging around during hurricane season, I dont give a damn what models or experts say. Especially when they say "nothing expected thru the next 5+days"
Member Since: July 14, 2008 Posts: 2 Comments: 9680
Quoting TxHurricanedude11:
Its best to stop asking questions please,it gets annoying sometimes.
A discussion includes questions and answers. Some of us do not have all the answers.
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KOTG, don't remember you saying anything about it
Member Since: July 14, 2008 Posts: 2 Comments: 9680
Quoting Stormchaser2007:


Shortwave will move across the US and drag this to the NE in about 48-72 hours.
How can the shortwave affect the storm with the ridge in the way?
Member Since: August 29, 2008 Posts: 0 Comments: 324
Quoting RitaEvac:
So Wunderground blog gets a D too?!
i want a rating as well how did i do forecasting the system
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Quoting stormwatcherCI:
They were showing development but seems like a little further north. Predictions cannot be an exact science as conditions are constantly changing.


yeah, thats why I'm not bashing the models because I posted those model runs in the blog..the low did set up more south but that was to be expected with the front and the trickery of these types of set ups
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Quoting RitaEvac:
TAZ does Masters get a poor rating too for this?



nop he gets a C
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Quoting ackee:
HOW WOULD U RATE THE NHC HANDLE OF TD#2/Bert SO FAR

A GOOD

B FAIR

C AVERAGE

D POOR


A.

But possible TS Bert...not so good. :)
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I'd give them above average marks, I only question the track.
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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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