Tropical Depression Eleven forms

By: Dr. Jeff Masters , 3:13 PM GMT on November 04, 2009

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Tropical Depression Eleven has formed in the Southwestern Caribbean, off the coast of Costa Rica, and appears poised to intensify into Tropical Storm Ida later today. TD 11 has increased its organization and heavy thunderstorm activity this morning, and visible satellite loops clearly show the rotation of TD 11's cloud pattern. The presence of a surface circulation was not evident in this morning's QuikSCAT pass, but the satellite presentation of TD 11 was convincing enough to allow NHC to declare this a tropical depression. QuikSCAT saw top winds in the 25 - 30 mph range this morning, and winds at San Andreas Island, about 80 miles north of the center of TD 11, were easterly at 28 mph at 9am EST.


Figure 1. Morning satellite image of TD 11 over the Atlantic off the coast of Costa Rica, Invest 96E over the East Pacific off the coast of Guatemala, and cloudiness over the Gulf of Mexico's Bay of Campeche associated with the remains of an old cold front.

TD 11 is currently under moderate wind shear, 10 - 15 knots, and shear is expected to remain in the moderate range as long as the storm remains south of 14N latitude (central Nicaragua). Sea Surface Temperatures (SSTs) are 29°C and the Tropical Cyclone Heat Potential is about 40 kJ/cm^2, which is plenty of energy for a hurricane to form, if the center remains over water long enough. There is dry air over the northern Caribbean, but this is too far north to slow down development. A limiting factor for development may be the formation of a tropical disturbance (Invest 96E) 500 miles to its west, over the Eastern Pacific south of Guatemala. If this new disturbance grows strong enough, it may compete with TD 11 for moisture.

The forecast for TD 11
The forecast for TD 11 is highly complex with high uncertainty. Steering currents are weak in the Southwest Caribbean, and TD 11 will move slowly over the next two days. The future steering of TD 11 will strongly depend upon the development and track of the Invest 96E disturbance 500 miles to its west. If 96E develops and tracks northwards towards Guatemala, as suggested by the GFDL model, TD 11 would likely be steered northwards later this week, remaining over water as it approaches the Cayman Islands on Monday. If, on the other hand, 96E moves due west away from 97E, as suggested by the NOGAPS model, 97E might also move due west, over Nicaragua, and emerge over the Eastern Pacific early next week. Another complicating influence might be the development of an extratropical or subtropical storm in the Gulf of Mexico's Bay of Campeche on Saturday or Sunday. The GFS and ECMWF models are predicting the formation of a low pressure system over the Bay of Campeche this weekend, along the remains of an old cold front. This low is expected to track northwards towards Louisiana, and might act to also pull TD 11 northwards. The exact amount of steering influence this extratropical low and 96E might have on TD 11 depends strongly on how large and intense TD 11 becomes. At present, TD 11 is a very small system, and so is only being affecting by steering influences in its immediate vicinity.

If TD 11 intensifies into a tropical storm in the next three days, as seems likely, the storm will probably tap into moisture from the Pacific Ocean. This moisture will flow over Costa Rica, western Panama, and southern Nicaragua into TD 11's circulation, bringing 3 - 6 inches of rain today through Friday. Heavier rains are likely along the east coast of Nicaragua, where an intense spiral band of rainfall has formed this morning. An Air Force Hurricane Hunter mission is scheduled to investigate TD 11 this afternoon to see if it has become Tropical Storm Ida.


Figure 2. Estimated rainfall amounts from Typhoon Mirinae. Rainfall in excess of eight inches (200 mm, red colors) affected portions of central Vietnam. Image credit: NASA TRMM project.

Typhoon Mirinae kills at least 90 in Vietnam
Typhoon Mirinae hit Vietnam Monday as a Category 1 typhoon, dumping rains responsible for at least 90 deaths, with 22 people missing. Over 200,000 people were stranded, 700 homes destroyed, and 13,000 homes damaged by the typhoon. Mirinae intensified suddenly just before landfall, bringing rainfall in excess of 8 inches (200 mm) to portions of central Vietnam (Figure 2). In the Philippines, rainfall amounts were lower--generally less than six inches. Mirinae killed at least 27 people in the Philippines.

Jeff Masters

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829. GTcooliebai
10:57 PM GMT on November 04, 2009
Lots of warm water ahead of Ida in fact because of its slow movement and TCHP it could get pretty strong for a Nov. system. Lets wait, watch, and see how everything plays out.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
828. GTcooliebai
10:55 PM GMT on November 04, 2009
Hey wats up everyone, seems the action is starting to heat up in this blog.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
827. markymark1973
9:52 PM GMT on November 04, 2009
Ida is about to make landfall soon and if the forecast track holds with the slow drifting over Nicaragua and Honduras it's most likely toast. It needs to stay on a NNW coarse to have a chance being anything substantial to talk about for the GOM. If the LLC had been located further to the east i would be more worried about this system if i lived in the GOM. I am very surprised this storm managed to get going like it did.
826. tropicofcancer
9:49 PM GMT on November 04, 2009
new blog
Member Since: September 19, 2006 Posts: 0 Comments: 141
825. jipmg
9:48 PM GMT on November 04, 2009
mhm interesting, wasn't GFDL showing a movement to the NNW yesterday after a WNW movement, and upping it into a strong TS around 8PM?
824. xcool
9:44 PM GMT on November 04, 2009
Member Since: September 26, 2009 Posts: 2 Comments: 15603
823. hcubed
9:43 PM GMT on November 04, 2009
Quoting NRAamy:
has tacoman given us his opinion on the TD this afternoon? I need to add it to my analysis.


Last analysis given by tacoman said that it wouldn't be a TS for the next 24 hours.
Member Since: May 18, 2007 Posts: 289 Comments: 1639
822. Orcasystems
9:43 PM GMT on November 04, 2009
Member Since: October 1, 2007 Posts: 81 Comments: 26493
821. BurnedAfterPosting
9:41 PM GMT on November 04, 2009
Quoting 1900hurricane:

I believe the reason that 115 kts is rounded to 135 mph is because the 132.34 mph, while closer to 130 than to 135, lies above the threshold for a Category 4 hurricane, while 130 mph does not.


good post and you are right that is why they round it up to 135mph,

also 170mph is not skipped
820. hydrus
9:39 PM GMT on November 04, 2009
Quoting NRAamy:
has tacoman given us his opinion on the TD this afternoon? I need to add it to my analysis.
Yes, and a few other things.
Member Since: September 27, 2007 Posts: 1 Comments: 19504
819. xcool
9:39 PM GMT on November 04, 2009
i seeing eye ??
Member Since: September 26, 2009 Posts: 2 Comments: 15603
818. hurricanejunky
9:38 PM GMT on November 04, 2009
Quoting tornadodude:


yeah, you guys could use the rain for sure


We're running a 20 inch rain deficit, I'd like a nice 6-8 inches worth of rain!
Member Since: August 28, 2006 Posts: 6 Comments: 2895
817. 1900hurricane
9:38 PM GMT on November 04, 2009
Quoting StSimonsIslandGAGuy:
45 kts converts to 52 mph, so it rounds to 50 mph. 50 kts converts to 58 mph, so it rounds up to 60 mph. 55 mph is skipped. The same thing happens to 95 mph--80 kts converts to 92 mph, and is rounded to 90 mph--85 kts converts to 98 mph and rounds to 100 mph.

30 kts - 34.52 mph, rounds to 35 mph
35 kts - 40.28 mph, rounds to 40 mph
40 kts - 46.03 mph, rounds to 45 mph
45 kts - 51.79 mph, rounds to 50 mph
50 kts - 57.54 mph, rounds to 60 mph (55 mph skipped)
55 kts - 63.29 mph, rounds to 65 mph
60 kts - 69.05 mph, rounds to 70 mph
65 kts - 74.80 mph, rounds to 75 mph
70 kts - 80.55 mph, rounds to 80 mph
75 kts - 86.31 mph, rounds to 85 mph
80 kts - 92.06 mph, rounds to 90 mph
85 kts - 97.82 mph, rounds to 100 mph (95 mph skipped)
90 kts - 103.57 mph, rounds to 105 mph
95 kts - 109.32 mph, rounds to 110 mph
100 kts - 115.08 mph, rounds to 115 mph
105 kts - 120.83 mph, rounds to 120 mph
110 kts - 126.58 mph, rounds to 125 mph
115 kts - 132.34 mph, rounds to 130 mph (for some reason, they round it up to 135 mph, and skip 130 mph)
120 kts - 138.09 mph, rounds to 140 mph
125 kts - 143.85 mph, rounds to 145 mph
130 kts - 149.60 mph, rounds to 150 mph
135 kts - 155.36 mph, rounds to 155 mph
140 kts - 161.11 mph, rounds to 160 mph
145 kts - 166.86 mph, rounds to 165 mph
150 kts - 172.62 mph, rounds to 175 mph (I can't remember if 170 mph is skipped or not)
155 kts - 178.37 mph, rounds to 180 mph
160 kts - 184.12 mph, rounds to 185 mph

I believe the reason that 115 kts is rounded to 135 mph is because the 132.34 mph, while closer to 130 than to 135, lies above the threshold for a Category 4 hurricane, while 130 mph does not.
Member Since: August 2, 2006 Posts: 45 Comments: 11556
816. atmoaggie
9:38 PM GMT on November 04, 2009
I think I am going to ignore the 18 Z models completely...they will have a bad, non-representative initialization...
The 0 Z models will be the first cycle with an actual system initialized, thanks to the recon.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
815. Stormchaser2007
9:37 PM GMT on November 04, 2009
AMSUB
Member Since: June 9, 2007 Posts: 4 Comments: 15718
814. msinformed
9:37 PM GMT on November 04, 2009
Quoting atmoaggie:
Okay, Ida, it is fine if you want to not develop all that well and follow the BAMS route rather than the BAMD route...



I'll say ... considering I just recently arrived to spend some "quiet-time" at my camp on Belle River in Pierre Part, LA.

On the other hand, puh-leeze don't let it go anywhere near Galveston, which is 20 miles south of my residence!!!!
Member Since: September 8, 2008 Posts: 0 Comments: 26
813. Cavin Rawlins
9:37 PM GMT on November 04, 2009
It kinda did what it did over minimal heat content

Member Since: July 24, 2005 Posts: 407 Comments: 19076
812. xcool
9:37 PM GMT on November 04, 2009


Member Since: September 26, 2009 Posts: 2 Comments: 15603
811. tornadofan
9:36 PM GMT on November 04, 2009
NEW BLOG
Member Since: April 5, 2007 Posts: 83 Comments: 12345
810. MiamiHurricanes09
9:36 PM GMT on November 04, 2009
Ida looking well organized. Could be our next hurricane (In the next 6 hours). After Ida goes into the western Caribbean/GOM it should intensify rapidly and on from there.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
808. Cavin Rawlins
9:34 PM GMT on November 04, 2009
Quoting BurnedAfterPosting:


well people in Nicaragua would disagree lol, but for everyone else yea your right


well yea, lol, something is given and taken.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
807. Grothar
9:34 PM GMT on November 04, 2009
Quoting StormW:
634. hurricanejunky 3:45 PM EST on November 04, 2009
Quoting Grothar:


A drop of one millibar per hour is considered “rapid intensification.” I believe this to be true. Could be wrong, often am.


Thanks Grothar. That's what I was thinking of.


No...a drop of 3mb per hour is considered a rapid drop in barometric pressure


Hey Storm, thought you were by buddy. Go ahead embarrass me on the blog. I was trying to help hurricanjunky. This is what I found on the NHC Glossary of terms. I know it is not really important, but is there a difference between "rapid intensification" and rapid deepening"?

Glossary of NHC Terms:
Rapid Deepening:
A decrease in the minimum sea-level pressure of a tropical cyclone of 1.75 mb/hr or 42 mb for 24 hours.
Member Since: July 17, 2009 Posts: 63 Comments: 23703
806. tornadofan
9:34 PM GMT on November 04, 2009
Quoting Stormchaser2007:


Yep it even had eye.


Yeah - but was 18 hours late.
Member Since: April 5, 2007 Posts: 83 Comments: 12345
805. xcool
9:34 PM GMT on November 04, 2009
GFDL NAIL IT 100% ,I SEEING A 75H COMEING SOON IMO.!!! opps cap lock
Member Since: September 26, 2009 Posts: 2 Comments: 15603
804. NRAamy
9:33 PM GMT on November 04, 2009
has tacoman given us his opinion on the TD this afternoon? I need to add it to my analysis.
Member Since: January 24, 2007 Posts: 316 Comments: 31944
803. Cavin Rawlins
9:33 PM GMT on November 04, 2009
Quoting tornadofan:


Didn't the model call for this much strengthening in 6 hours yesterday afternoon?


It called for a tropical storm in 6 hrs, but it also called for strong tropical storm in 24 hrs and that was valid 18Z today. That is the part we were pointing to.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
802. tornadodude
9:32 PM GMT on November 04, 2009
Quoting hurricanejunky:


No doubt. It's interesting we're finally seeing a storm that has favorable conditions.
This one has been pretty aggressive.
I think land will knock it back down so I don't know that it's necessarily a big deal. I'm wishcasting a weak storm passing over us for the rain event!


yeah, you guys could use the rain for sure
Member Since: June 28, 2006 Posts: 24 Comments: 8185
801. StormChaser81
9:31 PM GMT on November 04, 2009
Quoting hurricanejunky:


It was in response to a response about the storm. Quit trying to stir trouble. Jeez...


Just poof her, I did and everything is better now.lol

Member Since: August 11, 2008 Posts: 0 Comments: 2315
800. BurnedAfterPosting
9:31 PM GMT on November 04, 2009
Quoting Weather456:
I will go with the NHC track but would not leave a NNW turn out of the question. Key facts in intensity obviously is land and how long it stays over. Worst case scenario would be it skirted the landmass. Best case scenario would be in moves inland too far.


well people in Nicaragua would disagree lol, but for everyone else yea your right
799. atmoaggie
9:31 PM GMT on November 04, 2009
Quoting DrNo:
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog entry itself. Please do not engage in personal attacks or bickering. Material not conforming to these standards should be flagged with the button and ignored.

Like this post? Ok, done.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
798. Stormchaser2007
9:31 PM GMT on November 04, 2009
Quoting tornadofan:


Didn't the model call for this much strengthening in 6 hours yesterday afternoon?


Yep it even had eye.
Member Since: June 9, 2007 Posts: 4 Comments: 15718
797. KEEPEROFTHEGATE (Mod)
9:31 PM GMT on November 04, 2009
Member Since: July 15, 2006 Posts: 163 Comments: 52216
796. hurricanejunky
9:31 PM GMT on November 04, 2009
Quoting tornadodude:


HJ,

it should definitely be interesting to watch what it does in the next 12 hrs our so


No doubt. It's interesting we're finally seeing a storm that has favorable conditions.
This one has been pretty aggressive.
I think land will knock it back down so I don't know that it's necessarily a big deal. I'm wishcasting a weak storm passing over us for the rain event!
Member Since: August 28, 2006 Posts: 6 Comments: 2895
795. MiamiHurricanes09
9:31 PM GMT on November 04, 2009
Looking at Ida's steering currents is like finding a pin in a haystack. Latest currents mostly rely on 96E and where it moves to. At this moment in time Ida will continue to move WNW. As it leaves the area of land to its' northwest it should continue N. Intrests in (except Nicaragua and surronding areas) the Cayman Islands, Western Cuba, Yucatan Peninsula, Florida, and Gulf coast should monitor Ida.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
794. reedzone
9:31 PM GMT on November 04, 2009
Quoting Stormchaser2007:


Recon shows it moving NNW.


Wait.. wouldn't that give Ida more time to... umm.. oh boy :/

Tonights gonna be an interesting night, Hurricane Ida anyone? Maybe rapid intensification is occuring while the Hurricane Hunters are investigating after all. Went from a 35 mph. TD, maybe a 40 mph. TS to a whopping 60 mph. Tropical Storm with a developing eye. That says something right there..
Member Since: July 1, 2008 Posts: 13 Comments: 7334
793. atmoaggie
9:31 PM GMT on November 04, 2009
Okay, Ida, it is fine if you want to not develop all that well and follow the BAMS route rather than the BAMD route...

Member Since: August 16, 2007 Posts: 6 Comments: 12461
791. DrNo
9:30 PM GMT on November 04, 2009
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog entry itself. Please do not engage in personal attacks or bickering. Material not conforming to these standards should be flagged with the button and ignored.
790. WxLogic
9:30 PM GMT on November 04, 2009
Another bad initialization on GFS. Has the system as a 1010MB still...

Member Since: August 14, 2008 Posts: 4 Comments: 4881
789. Drakoen
9:30 PM GMT on November 04, 2009
Quoting Weather456:
I will go with the NHC track but would not leave a NNW turn out of the question. Key facts in intensity obviously is land and how long it stays over. Worst case scenario would be it skirted the landmass. Best case scenario would be in moves inland too far.


Agreed. Right now I am with the NHC track and the eastern guidance.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
788. tornadofan
9:29 PM GMT on November 04, 2009
Quoting Weather456:


I am speechless and the model was laughed at...


Didn't the model call for this much strengthening in 6 hours yesterday afternoon?
Member Since: April 5, 2007 Posts: 83 Comments: 12345
787. Cavin Rawlins
9:29 PM GMT on November 04, 2009
I will go with the NHC track but would not leave a NNW turn out of the question. Key facts in intensity obviously is land and how long it stays over. Worst case scenario would be it skirted the landmass. Best case scenario would be in moves inland too far.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
786. hurricanejunky
9:29 PM GMT on November 04, 2009
Quoting NRAamy:
776. hurricanejunky 1:26 PM PST on November 04, 2009
Quoting TheCaneWhisperer:


Or dinner time maybe?


Ya never know!


still off topic....tsk tsk tsk....


It was in response to a response about the storm. Quit trying to stir trouble. Jeez...
Member Since: August 28, 2006 Posts: 6 Comments: 2895
785. KEEPEROFTHEGATE (Mod)
9:29 PM GMT on November 04, 2009
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 04 NOV 2009 Time : 201500 UTC
Lat : 11:57:11 N Lon : 82:36:33 W


CI# /Pressure/ Vmax
2.7 /1003.0mb/ 39.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.7 3.0 3.5

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : -59.7C Cloud Region Temp : -58.1C

Scene Type : CURVED BAND with 0.58 ARC in BLACK

Positioning Method : FORECAST INTERPOLATION

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

Tno/CI Rules : Constraint Limits : 0.2T/hour
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

****************************************************
Member Since: July 15, 2006 Posts: 163 Comments: 52216
784. tornadodude
9:29 PM GMT on November 04, 2009
Quoting hurricanejunky:
Maybe a hurricane after Dmax?


HJ,

it should definitely be interesting to watch what it does in the next 12 hrs our so
Member Since: June 28, 2006 Posts: 24 Comments: 8185
783. TheCaneWhisperer
9:28 PM GMT on November 04, 2009
The Western Caribbean was hungry, sheeesh
782. NRAamy
9:28 PM GMT on November 04, 2009
776. hurricanejunky 1:26 PM PST on November 04, 2009
Quoting TheCaneWhisperer:


Or dinner time maybe?


Ya never know!


still off topic....tsk tsk tsk....
Member Since: January 24, 2007 Posts: 316 Comments: 31944
781. hurricanejunky
9:28 PM GMT on November 04, 2009
Quoting reedzone:
BIG shift in what direction?? I'm confused..


I don't see much shift, it looks to be moving NW to NNW. Agree?
Member Since: August 28, 2006 Posts: 6 Comments: 2895
780. KEEPEROFTHEGATE (Mod)
9:28 PM GMT on November 04, 2009
11L
TROPICAL DEPRESSION ELEVEN 18:00UTC 04November2009
UW-CIMSS Experimental Vertical Shear and TC Intensity Trend Estimates

Current Conditions (from TPC) :
Latitude : 11:44:02 N
Longitude : 82:08:02 W
Intensity (MSLP) : 1009.0 hPa

Max Pot Int (MPI,from Emanuel) : 908.2 hPa
MPI differential (MSLP-MPI) : 100.8 hPa

CIMSS Vertical Shear Magnitude : 4.6 m/s
Direction : 259.4 deg

Outlook for TC Intensification Based on Current
Env. Shear Values and MPI Differential
Forecast Interval : 6hr 12hr 18hr 24hr
F F F F

Legend : VF-Very Favorable F-Favorable N-Neutral
U-Unfavorable VU-Very Unfavorable

-- Mean Intensity Trend (negative indicates TC deepening) --
6hr 12hr 18hr 24hr
VF <-3.0mb/ 6hr <-6.0mb/12hr <-9.0mb/18hr <-12.0mb/24hr
F -3.0 - -1.0 -6.0 - -2.0 -9.0 - -3.0 -12.0 - -4.0
N -1.0 - +1.0 -2.0 - +2.0 -3.0 - +3.0 -4.0 - +4.0
U +1.0 - +3.0 +2.0 - +6.0 +3.0 - +9.0 +4.0 -+12.0
VU >+3.0 >+6.0 >+9.0 >+12.0

Member Since: July 15, 2006 Posts: 163 Comments: 52216
779. Drakoen
9:27 PM GMT on November 04, 2009
Quoting Stormchaser2007:


Wow the GFDL was right.



Yea.
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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.