Little change to 99L, which remains very close to tropical depression status

By: Dr. Jeff Masters , 7:11 PM GMT on October 20, 2010

Share this Blog
2
+

A tropical disturbance (Invest 99L) centered 160 miles southwest of the Cayman Islands is moving south to southeast at 5 - 10 mph. A Hurricane Hunter flight arrived in the storm at about 11am this morning, and found a closed circulation with top winds at flight level (700 feet) of 33 mph. A closed circulation and 30 mph surface winds are necessary conditions for a tropical depression to exist, but the storm must also have a great deal of heavy thunderstorm activity near the center that persists for many hours. In the judgment of NHC, 99L does not qualify as a tropical depression in that regard. The storm is bringing heavy rain to the Cayman Islands; 4.14" inches has fallen over the past 2 1/2 days at Savannah on Grand Cayman Island. Heavy rains have diminished over the Cayman Islands, but have spread to western Jamaica and west-central Cuba this afternoon. Recent satellite imagery shows that the surface circulation center is exposed to view, and 99L has a relatively meager amount of heavy thunderstorm activity. The center is more than 80 miles west of the heaviest thunderstorm activity, and it is likely that 99L's center will relocate itself to the east to be more underneath the heaviest thunderstorms. Wind shear is marginal for development, 15 - 20 knots, due to the clockwise flow of air around an upper-level high pressure system near the coast of Honduras. The high is bringing strong upper-level winds out of the southwest to 99L. Water vapor satellite loops show considerable dry air to the west and north of 99L, and the strong southwesterly winds over the storm are bringing some of this dry into into the core of the storm, keeping all the heavy thunderstorm development confined to the east side of the center. The waters beneath 99L are very warm, 29°C, but 99L will not be able to take advantage of these warm waters until the shear relaxes. A new hurricane hunter aircraft will be in the storm tonight near 8pm EDT.

Forecast for 99L
The current southward movement of 99L is carrying the storm into a region of lower wind shear, and we should see 99L accumulate more heavy thunderstorm activity near its center beginning tonight. The latest SHIPS model forecast predicts that wind shear over the Western Caribbean will decline below 15 knots Thursday afternoon through Saturday afternoon, which should allow the storm to become a tropical depression by Thursday. Steering currents will be weak today through Friday in the Western Caribbean, making it difficult to predict where 99L may go. The models are split into two camps, with the GFDL and HWRF models taking 99L to the west-northwest over the western tip of Cuba or the Yucatan Peninsula on Sunday as a hurricane. The rest of the models take 99L to the south over Honduras on Sunday, and keep the storm below hurricane strength. Given 99L's current southward motion and the possibility that the center will relocate farther to the east later today, this makes a track to the southwest towards Honduras more likely, I predict. NHC is giving 99L a 70% chance of developing into a tropical depression by Friday, which is a reasonable forecast. I expect this will become Tropical Storm Richard by Friday.


Figure 1. Afternoon satellite image of Invest 99L.

Death toll from Super Typhoon Megi in the Philippines remarkably low
The power is still out and communications are down over the majority of the northern portion of the Philippines' Luzon Island blasted by Typhoon Megi yesterday, so the full extent of the destruction wrought by the great storm is still unclear. However, the death toll from the great storm stands at only 19, reflecting the superior effort Philippines officials made to evacuate low-lying areas and get people out of locations prone to flash flooding and mudslides. Previous major typhoons to strike the Philippines have nearly always killed hundreds, and sometime thousands, so the preparation and evacuation efforts for Megi likely saved hundreds of lives. Megi hit Luzon on Monday morning at 3:30 UTC as a Category 5 super typhoon with sustained winds of 165 mph and a central pressure of 914 mb. Severe damage was done to Isabela Province in northern Luzon, and media reports indicate that 200,000 people are homeless.


Figure 2. Visible MODIS satellite image of Megi from NASA's Aqua satellite taken at 1:30am EDT October 20, 2010. At the time, Megi was a Category 4 typhoon with 135 mph winds. Image credit: NASA.

Passage over Luzon Island destroyed Megi's eyewall and inner core region, and the storm compensated by expanding and intensifying the portions of its circulation that were over water. Now that its center is back over water in the South China Sea, Megi has re-developed its inner core and has intensified into a formidable Category 3 typhoon with 125 mph winds. Megi has been able to maintain its larger size, and is now a much larger typhoon than when it hit the Philippines. This is similar to what happened to Hurricane Ike in 2008 when it passed over Cuba, and helped give Ike a very destructive storm surge when it came ashore over Texas. Wind shear is a low 5 - 10 knots over Megi, and the waters of the South China Sea have a very high total heat content to great depth, so Megi should be able to remain a very dangerous major typhoon through Friday. The larger size of Megi means that it will be able to deliver a significant storm surge in excess of ten feet to the coast of China of Friday or Saturday, when the storm is expected to make landfall north of Hong Kong. As the storm approaches the coast on Friday, wind shear is expected to rise to the moderate or high range, and the total heat content of the ocean will drop significantly, so some weakening is to be expected. Still, Megi will probably hit China as a major Category 3 typhoon, or as a strong Category 2, bringing a significant storm surge, high winds, and widespread torrential rains that will likely make this a multi-billion dollar disaster for China. The outer rain bands of Megi are already affecting the coast of China north of Hong Kong, as seen on Hong Kong radar and Taiwan radar.


Figure 3. Still frame of damage to NE Luzon Island from a video posted to YouTube by storm chaser James Reynolds of typhoonfury.com.

Next update
I'll have an update Thursday morning.

Jeff Masters

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: 226 - 176

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24Blog Index

Yes, I have that one. Crank up the speed & zoom way in - coc is very clear.
Member Since: Posts: Comments:
Quoting FLWaterFront:


Nope. Don't remember that one but that sounds a little like TS Bonnie from earlier this year, if that is what you mean.

Back in 2004, Hurricane Ivan looped around the entire SE quadrant of the CONUS as a TD then a remnant low, then came back through Florida, crossed the Gulf and went into SE Texas as a weak TS, if I am recalling it right.


Yup you're right.

Member Since: Posts: Comments:
Quoting wunderkidcayman:
nice Levi32 by the way how was your B-Day


It was good thanks =)
Member Since: Posts: Comments:
12z ECMWF is catching on now, finally, along with the rest of the models. Amazing how the logical track and development idea is unfolding before our eyes when every computer said otherwise.

Member Since: Posts: Comments:
nice Levi32 by the way how was your B-Day
Member Since: Posts: Comments:
Quoting WeatherNerdPR:

It was 94L, but lol.


LOL!

The "little wave that could"! (Or could not...)

No, it wasn't Bonnie, because this never got named in the ATL.
Member Since: Posts: Comments:
Quoting Levi32:
As mentioned earlier, the dominant surface vortex is being drawn east now because it is not the main center, but is rotating about a mean circulation center that has been northeast of it during the afternoon. On visible imagery you can clearly see the circulation as a whole is trying to tighten eastward towards the convective cluster, and for now is broad with multiple vortices as a secondary one is developing closer to the convection, northeast of what is currently still the most obvious spinner on satellite imagery.

This also shows how 99L was not diving SSE earlier, because the dominant vortex is not the actual center of the system. Considering the circulation as a whole, movement has been nearly stationary or a very slight drift southeastward throughout the day so far.


I had primitive ape-like thoughts in my head about what was going on with 99L right now. Thanks as usual for putting it into words so wonderfully Levi.
Member Since: Posts: Comments:
Quoting BLee2333:


Guess you don't remember the long lived 95L (I could have the # wrong) which crossed nearly the ENTIRE ATL basin, crossed FL into the GOM, LOOKED like a TS over NO, looped through LA, MS, AL, GA, back into the the GOM, crossed MEX, and I believe may have gotten renumbered and eventually named in the PAC...

There were comments joking about it eventually hitting Japan as a supertyphoon!


Nope. Don't remember that one but that sounds a little like TS Bonnie from earlier this year, if that is what you mean.

Back in 2004, Hurricane Ivan looped around the entire SE quadrant of the CONUS as a TD then a remnant low, then came back through Florida, crossed the Gulf and went into SE Texas as a weak TS, if I am recalling it right.
Member Since: Posts: Comments:
Quoting FLWaterFront:


Something just occurred to me..

This could just possibly be a record for the most attention ever paid for so long by so many to a tropical system while it was still just an invest!

"I think I see a little bit more convection off to the right..."

"It might be able to get its COC underneath the coldest cloud tops within a few hours."

"Hey! Is that a new swirl I'm seeing forming near Grand Cayman??"

"OK it's nothing yet but just wait, in six days it's gonna be a Cat 4 or a Cat 5 closing in on Naples!"

"I say it becomes a TD by 5PM."

"No, I say it becomes one by 11."

(LOL)

Believe it or not, there was once a time when no one at all except for professional meteorologists paid any attention to these things at all until they were at least officially a tropical cyclone and not usually until they were a hurricane that was posing a direct threat to somebody.

Ahh, the Information Age!



the information age is the age of peole losing their minds. Have you ever tried using a computer that is loaded with too much junk? Well we usually yell at those computers and call them stupid.

The same is happening with people today. To avoid losing your mind, just because we have the technology to be aware of everything occurring in the world doesn't mean we should embrace it. Our brains our designed to know a lot focused on what we do, that we might become masters of that skill. Our brains are not designed to be packed full of meaningless junk like a computer that has too many downloads.
Member Since: Posts: Comments:
As mentioned earlier, the dominant surface vortex is being drawn east now because it is not the main center, but is rotating about a mean circulation center that has been northeast of it during the afternoon. On visible imagery you can clearly see the circulation as a whole is trying to tighten eastward towards the convective cluster, and for now is broad with multiple vortices as a secondary one is developing closer to the convection, northeast of what is currently still the most obvious spinner on satellite imagery.

This also shows how 99L was not diving SSE earlier, because the dominant vortex is not the actual center of the system. Considering the circulation as a whole, movement has been nearly stationary or a very slight drift southeastward throughout the day so far.
Member Since: Posts: Comments:
Quoting BLee2333:


Guess you don't remember the long lived 95L (I could have the # wrong) which crossed nearly the ENTIRE ATL basin, crossed FL into the GOM, LOOKED like a TS over NO, looped through LA, MS, AL, GA, back into the the GOM, crossed MEX, and I believe may have gotten renumbered and eventually named in the PAC...

There were comments joking about it eventually hitting Japan as a supertyphoon!

It was 94L, but lol.
Member Since: Posts: Comments:
Good Afternoon.

Member Since: Posts: Comments:
yep stormpetrol so it seems that the HWRF is right hope you are ready for it when it comes
Member Since: Posts: Comments:
Quoting FLWaterFront:


Something just occurred to me..

This could just possibly be a record for the most attention ever paid for so long by so many to a tropical system while it was still just an invest!

"I think I see a little bit more convection off to the right..."

"It might be able to get its COC underneath the coldest cloud tops within a few hours."

"Hey! Is that a new swirl I'm seeing forming near Grand Cayman??"

"OK it's nothing yet but just wait, in six days it's gonna be a Cat 4 or a Cat 5 closing in on Naples!"

"I say it becomes a TD by 5PM."

"No, I say it becomes one by 11."

(LOL)

Believe it or not, there was once a time when no one at all except for professional meteorologists paid any attention to these things at all until they were at least officially a tropical cyclone and not usually until they were a hurricane that was posing a direct threat to somebody.

Ahh, the Information Age!


Guess you don't remember the long lived 95L (I could have the # wrong) which crossed nearly the ENTIRE ATL basin, crossed FL into the GOM, LOOKED like a TS over NO, looped through LA, MS, AL, GA, back into the the GOM, crossed MEX, and I believe may have gotten renumbered and eventually named in the PAC...

There were comments joking about it eventually hitting Japan as a supertyphoon!
Member Since: Posts: Comments:
I highly doubt this disturbance will head for Florida. These are early model tracks, and if this disturbance develops enough to become a tropical storm or hurricane, the models will shift away from Florida. The overall long term pattern does not support a hurricane making landfall in Florida.

For those who have short memories, early model guidance has shown this multiple times in the last 2 weeks to a month. But as time draws close, the models back off.

I also don't think whatever is down there will become much of anything. But that I'm not too confident on because predicting intensity of tropical systems is very poor.
Member Since: Posts: Comments:
Quoting whadat:
Yep. gregmerren. This system is killing me - don't know whether to do all out prep with the big boat or just expect marginal TS winds. If it does get going I probably won't have anytime to do much.


Ah, that explains it it LOL

Run this loop and you will see the old center virtually disappear from view into the deep convection located at 17 N and 81 W. This strongly suggests that a center relocation is underway but I won't know for sure until I see another 4 frames or so load and run. Regardless, the steering will remain weak for the next couple of days so this is unlikely to come up on us quickly even if it develops.

From where it is now the more likely track is to the WNW but we are not out of the woods yet.
Hard to say whether to prep or not because this time of year they can go anywhere but all indications are for very slow motion at least through 24 hours.

Member Since: Posts: Comments:
Quoting Seastep:


Naaahhhh. This is nothing. Haven't been around long, huh? ;)


I just joined up recently but have been lurking here regularly for years.

What is different this time is that one, single, tropical system is getting so much attention and for so long while still just an invest.

Usually there's more to look at and more going on. Right now, this is the only show in town except for Megi/Juan but that is in the W PAC.
Member Since: Posts: Comments:
convection trying to fire up south of the COC
Member Since: Posts: Comments:
Pressure fell another 0.5mb to 1006.3 at 42057

Member Since: Posts: Comments:
COC of 99L getting underneath the convection now, TD/TS by 11 pm tonight IMO
Member Since: April 29, 2007 Posts: 0 Comments: 7663
so old COC is at 17.0N 82.0W and the new one forming NNE of the old COC and this is going to be bad news for us
Member Since: Posts: Comments:
Quoting FLWaterFront:


Something just occurred to me..

This could just possibly be a record for the most attention ever paid for so long by so many to a tropical system while it was still just an invest!

"I think I see a little bit more convection off to the right..."

"It might be able to get its COC underneath the coldest cloud tops within a few hours."

"Hey! Is that a new swirl I'm seeing forming near Grand Cayman??"

"OK it's nothing yet but just wait, in six days it's gonna be a Cat 4 or a Cat 5 closing in on Naples!"

"I say it becomes a TD by 5PM."

"No, I say it becomes one by 11."

(LOL)

Believe it or not, there was once a time when no one at all except for professional meteorologists paid any attention to these things at all until they were at least officially a tropical cyclone and not usually until they were a hurricane that was posing a direct threat to somebody.

Ahh, the Information Age!


Naaahhhh. This is nothing. Haven't been around long, huh? ;)
Member Since: Posts: Comments:
Yep. gregmerren. This system is killing me - don't know whether to do all out prep with the big boat or just expect marginal TS winds. If it does get going I probably won't have anytime to do much.
Member Since: Posts: Comments:
Quoting FLWaterFront:


Something just occurred to me..

This could just possibly be a record for the most attention ever paid for so long by so many to a tropical system while it was still just an invest!em>


You kidding me? This happens anytime an invest even has a remote chance of maybe possibly remotely heading towards FL or the Gulf.
Member Since: Posts: Comments:
Quoting reedzone:
BOTTOM LINE, we don't really know where this will go, we have clues and maps showing us the possibilities. This could and is likely to ramp up to a strong storm at best as it stalls in the Western Caribbean. Another thing is we need a TC to develop before we can pinpoint a track.


Something just occurred to me..

This could just possibly be a record for the most attention ever paid for so long by so many to a tropical system while it was still just an invest!

"I think I see a little bit more convection off to the right..."

"It might be able to get its COC underneath the coldest cloud tops within a few hours."

"Hey! Is that a new swirl I'm seeing forming near Grand Cayman??"

"OK it's nothing yet but just wait, in six days it's gonna be a Cat 4 or a Cat 5 closing in on Naples!"

"I say it becomes a TD by 5PM."

"No, I say it becomes one by 11."

(LOL)

Believe it or not, there was once a time when no one at all except for professional meteorologists paid any attention to these things at all until they were at least officially a tropical cyclone and not usually until they were a hurricane that was posing a direct threat to somebody.

Ahh, the Information Age!
Member Since: Posts: Comments:
Quoting whadat:
Thanks D.


??. You know me ?. Sounds familiar
Member Since: Posts: Comments:
back later this eve have a good eve yall
Member Since: Posts: Comments:
Dr. M also is favoring the track consensus towards the southern Yucatan.

Meanwhile, Jeff9641 thinks the GFDL is the most accurate model right now and Florida should watch out, Reed seems to be going with the Euro, with a weakening TS possibly turning towards the NE eventually. Most agree the HWRF is unrealistic.

Kman is closely watching data that may support a center reformation further east. The impostor impersonated StormW today. Oracle is closely watching the XTRP model. And ParanoidAndroid is having a very very slow day at work.
Member Since: Posts: Comments:
Back later
Member Since: Posts: Comments:
Thanks D.
Member Since: Posts: Comments:
Quoting Dakster:


Just as long as it goes away and doesn't become Wilma's evil brother.


some models are pointing to that but others not so much dont worrya bout it right now
Member Since: Posts: Comments:
194. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Disturbance Summary
TROPICAL DEPRESSION XX
3:00 AM JST October 21 2010
==============================

At 18:00 PM UTC, Tropical Depression (1008 hPa) located at 17.0N 161.0E has 10 minute sustained winds of 25 knots with gusts of 40 knots. The depression is reported as moving west northwest at 10 knots.
Member Since: Posts: Comments:
Quoting whadat:
http://www.ssd.noaa.gov/goes/flt/t1/flash-bd.html

COC near 17 & 82, drifting ese?


Exactly, and the steering has weakend further in the past 3 hours so expect the motion to start slowing to being almost stationary in the next few hours. A shift of the center due to relocation would not, of course, represent motion of the system itself if that were to happen.

Member Since: Posts: Comments:
Quoting weatherlover94:


let this thing take as long as it needs


Just as long as it goes away and doesn't become Wilma's evil brother.
Member Since: Posts: Comments:
http://www.ssd.noaa.gov/goes/flt/t1/flash-bd.html

COC near 17 & 82, drifting ese?
Member Since: Posts: Comments:
http://pulliamjr.com/sat/WESTERN_ATLANTIC%20_INFRA.htm
Member Since: Posts: Comments:
Quoting Dakster:
Taking its time I see... Not complaining...


let this thing take as long as it needs
Member Since: Posts: Comments:
Quoting Dakster:
Soooo.. What is the deal with 99L?

I thought it was supposed to be named by now?


Same old story. Shear, dry air. But Dr. M says:

"The current southward movement of 99L is carrying the storm into a region of lower wind shear, and we should see 99L accumulate more heavy thunderstorm activity near its center beginning tonight. The latest SHIPS model forecast predicts that wind shear over the Western Caribbean will decline below 15 knots Thursday afternoon through Saturday afternoon, which should allow the storm to become a tropical depression by Thursday."
Member Since: Posts: Comments:
MANILA, Philippines - The death toll from typhoon Juan rose on Wednesday to 15 with 20 injuries, civil defense authorities said.
Member Since: Posts: Comments:
Taking its time I see... Not complaining...
Member Since: Posts: Comments:
Quoting Dakster:
Soooo.. What is the deal with 99L?

I thought it was supposed to be named by now?


it looks to me like its trying hard to get that name
Member Since: Posts: Comments:
Quoting reedzone:
BOTTOM LINE, we don't really know where this will go, we have clues and maps showing us the possibilities. This could and is likely to ramp up to a strong storm at best as it stalls in the Western Caribbean. Another thing is we need a TC to develop before we can pinpoint a track.


you hit the nail on the head
Member Since: Posts: Comments:
Quoting Jeff9641:


Hey buddy keep us posted!


Will do.
Member Since: Posts: Comments:
Soooo.. What is the deal with 99L?

I thought it was supposed to be named by now?
Member Since: Posts: Comments:
Quoting Jeff9641:


I just posted the links and there is a new center forming just ene of the old one. The old one is wraping into the new one now.


It is possible that the center will migrate underneath the deep convection and I posted just recently that there was some suggestion it might be happening from looking at the visible loops. There are no surface obs as yet supporting that though.
Member Since: Posts: Comments:
Quoting Jeff9641:
The old COC is now wraping into a new center forming west of Jamaica. Kman you updates will be key tonight to see if this is the case.

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html


If the center relocates to the SE of us then NE winds would show up later this evening here.
Member Since: Posts: Comments:
so what are the approximate coordinates of where you think the low/coc is centered?
Member Since: Posts: Comments:

Viewing: 226 - 176

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24Blog 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.

Local Weather

Overcast
72 °F
Overcast