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

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

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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

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Link

This is the closest Radar we have till next year whaen one is "supposed" to be operational here...Island Time though not holding my breath lol
Member Since: October 21, 2009 Posts: 0 Comments: 362
Quoting EricSFL:


Thanks for the link. Do you know of any other link to a radar of the Cayman Islands?
Wind farm dropped for radar
Posted on Thu, 10/14/2010 - 19:39 in Headline News

(CNS): Proposals for a possible wind farm in East End have been stopped in its tracks as a result of the government’s plans to erect a Doppler radar in the same area. Hopes of opening up Cayman’s first an alternative energy source with a 200ft wind tower in the High Rock area have been dashed in favour of the radar project which government says will fill an important weather tracking black hole. The government said in a statement on Thursday evening that despite the need to find alternative energy sources the Ministry of Works said it was supporting the radar as a priority and could risk losing the funding if it didn't
Member Since: October 9, 2008 Posts: 0 Comments: 8347
Quoting stormwatcherCI:
No radar here.


Oh, OK.
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Tropical Update From Texas!
Tropical Update: Invest 99L Likely to become Richard; Shary Possible; Western Pacific Firing Up, With Video!
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I don't think the NHC will call it a TD until it is aleast a weak ts. They dont want many storms to olny be tropical for 6 hours or so.
Member Since: August 29, 2008 Posts: 0 Comments: 461
shear seems to have backed off a bit.
Member Since: August 14, 2008 Posts: 0 Comments: 1002
Quoting EricSFL:


Thanks for the link. Do you know of any other link to a radar of the Cayman Islands?
No radar here.
Member Since: October 9, 2008 Posts: 0 Comments: 8347
Quoting Saltydogbwi1:
just saw NNE on Savannah link also
South Sound reporting E winds.
Member Since: October 9, 2008 Posts: 0 Comments: 8347
Quoting Saltydogbwi1:
Winds now ENE here in grand cayman...savannah
Link


Thanks for the link. Do you know of any other link to a radar of the Cayman Islands?
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Quoting Saltydogbwi1:
Winds now ENE here in grand cayman...savannah
Link
I think when recon gets out there again the will find a TD or TS. Looks very good now compared to earlier today.
Member Since: October 9, 2008 Posts: 0 Comments: 8347
just saw NNE on Savannah link also
Member Since: October 21, 2009 Posts: 0 Comments: 362
Quoting Saltydogbwi1:
Winds now ENE here in grand cayman...savannah
Link
East End is reporting NNE.
Member Since: October 9, 2008 Posts: 0 Comments: 8347
Quoting beell:
Maybe one of these days ya'll will figure out the proper time and place to use the "dislike" and "report" tools.

Very effective if used correctly.
Best wishes, lol.

... plus 1
As admin intended, the ! is not meant to report trolls. It is meant to report offensive content, spam, or copyright violation. It worked here.
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One more storm for 2010 season?
Might get busy in here soon, based on possible USA landfall.
(snicker)
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Quoting NCHurricane2009:


Yeah, I am hooked. What's supposed to happen in the E Caribbean?


A storm could develop in the SE caribbean Sea then heads N then NNE crossing DR/PR... at least according to the GFS and 300Hrs away lol
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Winds now ENE here in grand cayman...savannah
Link
Member Since: October 21, 2009 Posts: 0 Comments: 362
Tropical Update From Texas!
Tropical Update: Invest 99L Likely to become Richard; Shary Possible; Western Pacific Firing Up, With Video!
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Quoting NCHurricane2009:


But only the HWRF is suggesting it moving into Florida, the rest suggest it going further west than that into th GOM, or even WSW across Central America and ending up in the E-Pac.

I agree...I just thought he was seeing something I wasn't since I am not a Meterologist :)
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Quoting NCHurricane2009:


I don't see this as an option, where's the choice for 5 AM tomorrow morning? That's when I am guessing this'll become TD 19.

sorry, typo, its suppose to be 5 am not 5 pm
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Quoting Orcasystems:
Complete Update

Florida appears to be the target of choice in the new model runs.



AOI
AOI AOI AOI

AOI AOI AOI

TS BUSTED FORECAST ALIBI


But only the HWRF is suggesting it moving into Florida, the rest suggest it going further west than that into th GOM, or even WSW across Central America and ending up in the E-Pac.
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302. beell
Maybe one of these days ya'll will figure out the proper time and place to use the "dislike" and "report" tools.

Very effective if used correctly.
Best wishes, lol.
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Quoting hurristat:
If this thing was located at 17.2N, 79.2W, I'd call it a tropical storm, based on satellite. (It kind of looks like it's centered there, as you can't see the actual COC :P)


LOL, yep. Sheared systems can look strong if you ID the center in the wrong spot. I remember that on here with Bonnie earlier this year.
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If this thing was located at 17.2N, 79.2W, I'd call it a tropical storm, based on satellite. (It kind of looks like it's centered there, as you can't see the actual COC :P)
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Quoting CaribBoy:


What could happen there?


Yeah, I am hooked. What's supposed to happen in the E Caribbean?
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Quoting 954FtLCane:

Dude, really? Who TF do you think you are.
Go to your TEA party rally and leave this blog now.


He's a Richard Head!
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Quoting HurricaneDean07:

looks like td 19 on its way.
Poll Time:
Do you think 99L will be TD Nineteen at the
(A) 8 PM today
(B) 11 PM tonight
(C) 2 AM tomorrow morning
(D) 5 PM tomorrow morning
(E) Not until late tomorrow


I don't see this as an option, where's the choice for 5 AM tomorrow morning? That's when I am guessing this'll become TD 19.
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Quoting IgnorantRacistInNOLA:
[Stupid, illiterate, racist and trollish rant deleted]

Go away, would you? Please?
Member Since: November 8, 2009 Posts: 4 Comments: 13526
Quoting Jeff9641:
THe Caymans better get ready as this seems to wanna go straight to Richard. The HWRF and GFDL seems to be right about intensity of this as there is one big convective mass very near the new center now.

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


yeah, this doesn't look that good for the Caymans. Quote from my blog on 99L and the Caymans:

"Cayman Islands: Looks like they will get the most rainfall. It has already rained there heavily with 99L's northern rain bands. Once the NE/stalled track reverses to a WNW track, another round of rain bands will add to the already heavy rainfall totals. Wind could become a problem if a strengthening Richard passes WNW through the islands while it tracks parallel to the S coast of Cuba."
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Quoting stormpetrol:
I thought Recon was flying 99L again this evening, Is it still on?
FLIGHT TWO - TEAL 71
A. 21/0000Z
B. AFXXX 0319A CYCLONE
C. 20/2030Z
D. 18.0N 82.5W
E. 20/2330Z TO 21/0330Z
F. SFC TO 15,000 FT
Member Since: October 9, 2008 Posts: 0 Comments: 8347
Quoting stormpetrol:
I thought Recon was flying 99L again this evening, Is it still on?


http://www.nhc.noaa.gov/text/MIAREPRPD_last.shtml?

Looks like the flight is still on according to the NHC Recon Plan of the Day (see link posted above).
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Quoting Levi32:


Yup. The pattern favors the eastern Caribbean next.


What could happen there?
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Quoting KerryInNOLA:
The Chinamen will be running for the hills soon as Megi approaches. I would stock up on rice and ratmeat if I were them.

Dude, really? Who TF do you think you are.
Go to your TEA party rally and leave this blog now. No spot for such comments on this blog.
This a weather blog and we are here to discuss weather not read your insensitive words.
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I thought Recon was flying 99L again this evening, Is it still on?
Member Since: April 29, 2007 Posts: 0 Comments: 7862
Afternoon all,

My updated forecast on 99L.

However, 99L seems to be really annoying. This updated forecast is the second one I issued on it, and it too (in terms of track) may be wrong. First I thought 99L would go ENE straight into E Cuba. Then I thought it would drift ENE from its current locatoin, and then turn WNW and head toward the west tip of Cuba. But now 99L is going ESE, and looks like it may turn WSW! Argghhh! LOL.
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286. xcool


like 12z gfs i posting
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285. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #6
TROPICAL DEPRESSION 18
6:00 AM JST October 21 2010
=================================

SUBJECT: Tropical Depression Near The Marianas

At 21:00 PM UTC, Tropical Depression (1004 hPa) located at 16.4N 144.0E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west northwest at 12 knots

Dvorak Intensity:

Forecast and Intensity
=======================
24 HRS: 16.0N 139.7E - 35 knots (CAT 1/Tropical Storm)
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283. HadesGodWyvern (Mod)
Hong Kong Observatory

Strong Wind Signal, No. 3


Tropical Cyclone Bulletin

Here is the latest Tropical Cyclone Bulletin issued by the
Hong Kong Observatory.

The Strong Wind Signal, No. 3 is in force.

This means that winds with mean speeds of 41 to 62
kilometres per hour are expected.

At 6 a.m., Severe Typhoon Megi was estimated to be about 480
kilometres southeast of Hong Kong (near 19.2 degrees north
117.4 degrees east) and is forecast to move north at about
10 kilometres per hour across the northern part of the South
China Sea and gradually edge closer to the south China
coast.
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until we have a stacked storm the models cannot fix a path. where are all the experts from yesterday saying the shear I mentioned was "good outflow" ???
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going buggy eyed trying to locate the LLC..
BUT, AFTER numerous runs of the Satellite Loops, and zoom ins and outs, both of Vsible and IR Loops, I would have to say 99L is getting its act together and the COC is at 17N/82W. Now we will have to wait and see if any convection will start building up in the next 12-24 hours or so, and if pre-Rich heads to the West and Northwest. So hard to tell what he may do....JMO
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Quoting PSLFLCaneVet:


Ah, they are twice as sweet when it lands in your lap. Are you sharing with them? LOL
I don't know what you're laughing at.
If you look at the visible satellite you can clearly see the LLC migrating towards the convection, and we see some convection beginning to fire up in the SW quadrant. All directly underneath an anticyclone.
We're entering diurnal max, and we have almost 5 hours for the NHC to make the call. Should convection increase markedly around the LLC, and considering the proximity to Jamaica and moreso the Caymans, the NHC will have to make the call.
.
.
TD at 11.
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Quoting TropicalMan2010:

gfs may turn out wrong this time


2nd storm in a row. Completely utterly failed with Paula and 99L.
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Quoting Tazmanian:




can we plzs stop with the polls plzs


I love the polls!!! - keep 'em coming!
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It won't explode I don't think. It's tightening up though ever so slowly. If the shear relaxes as Dr. M describes above, tomorrow could be an interesting day. Hopefully it doesn't drift north towards CI. Could be a very bad rain event just sitting there strengthening slowly.
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276. beell
Trough digging SSE (maybe not as much SE as modeled) from the central US. Trough base just nosing out into the north central GOM near the end of the WV loop.

Strong enough and deep enough to catch 99L?
Maybe...

PSU e-Wall WV Loop
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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.