99L a threat to develop; damage from Typhoon Megi still largely unknown

By: Dr. Jeff Masters , 1:38 PM GMT on October 19, 2010

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Heavy thunderstorm activity has increased and grown more organized this morning over the southwestern Caribbean between Honduras and the Cayman Islands, in association with a tropical disturbance (Invest 99L). The storm is bringing heavy rain to the Cayman Islands; two inches has fallen so far this morning at Savannah on Grand Cayman Island. Recent satellite imagery shows that 99L has some rotation, and the winds on the northeast coast of Honduras at Puerto Lempira have shifted to the west-northwest, implying that 99L may be developing a surface circulation. Wind shear is a moderate 10 - 20 knots, which is low enough to allow some slow development. Water vapor satellite loops reveal that the atmosphere in the Western Caribbean is moist enough to support development, and the waters beneath are plenty warm, at 29°C. The latest SHIPS model forecast predicts that wind shear over the Western Caribbean will mostly remain in the moderate range, 10 - 20 knots, for the remainder of the week. The current north-northwest motion of 99L should continue until Wednesday, when a strong ridge of high pressure is forecast to build in, forcing 99L to the south or west. However, steering currents will be weak Wednesday through Friday, making it difficult to predict where 99L may wander to. The only models that develop 99L are the GFDL and HWRF. The GFDL model predicts that 99L will spend enough time over water to develop into a hurricane, and brings the storm to the coast of Mexico's Yucatan Peninsula on Sunday morning. The HWRF model has 99L making landfall over Honduras late this week, before the storm has a chance to develop into a hurricane. NHC is giving 99L a 40% chance of developing into a tropical depression by Thursday. I believe the odds are higher, near 60%. The Hurricane Hunters are on call to investigate 99L this afternoon.


Figure 1. Morning satellite image of Invest 99L.

Damage from Super Typhoon Megi still largely unknown
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 extent of the destruction wrought by the great storm is still largely unknown. Preliminary news reports indicate that at least 10 people died, and the northern Philippine province of Isabela suffered severe damage. 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. Baguio near the west coast of northern Luzon received 7.72" of rain from the storm, and many mountainous regions likely received over a foot of rain.


Figure 2. Rainfall rates in excess of 1 inch per hour (orange colors) were observed by the polar-orbiting F-18 satellite in association with Megi at 00:40 UTC October 19, 2010. Image credit: Navy Research Lab, Monterey.

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 built a formidable new eyewall. At the same time, 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 intensify into a very dangerous Category 4 storm by Thursday. 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 near 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,bringing a significant storm surge, high winds, and widespread torrential rains that will likely make this a multi-billion dollar disaster for China.

"Daily Downpour" airing this afternoon
Our live Internet radio show, "Daily Downpour", will be airing today at 4pm EDT. The call in number is 415-983-2634, or you can post a question to broadcast@wunderground.com. You can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml, and I'll be discussing the latest info on Invest 99L with hosts Shaun Tanner and Tim Roche.

Jeff Masters

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675. Jeff9641
11:35 PM GMT on October 19, 2010
Quoting weatherlover94:


let me ask could we see a cat 2-3 going into Florida? is this the thinking?


If it stays over water then I think the GFDL is a good bet.
Member Since: November 4, 2009 Posts: 0 Comments: 6577
674. Dakster
11:34 PM GMT on October 19, 2010
8pm - still 70%
Member Since: March 10, 2006 Posts: 0 Comments: 10567
673. Dakster
11:33 PM GMT on October 19, 2010
Kinda looks like a TD has formed.. I doubt it will get classified until AT LEAST 11pm, but I've been wrong many times before.
Member Since: March 10, 2006 Posts: 0 Comments: 10567
672. Bordonaro
11:33 PM GMT on October 19, 2010
Typhoon Megi

Member Since: August 25, 2009 Posts: 20 Comments: 6785
671. weatherlover94
11:33 PM GMT on October 19, 2010
Quoting Jeff9641:


No, NW then NE rapidly in the eastern Gulf as a strong trough approaches.


let me ask could we see a cat 2-3 going into Florida? is this the thinking?
Member Since: September 8, 2010 Posts: 0 Comments: 2218
670. Jeff9641
11:32 PM GMT on October 19, 2010
Quoting stormwatcherCI:
Please tell me if I am understanding this correctly. Going NE until it reaches just south of Eastern Cuba and then back West ?


No, NW then NE rapidly in the eastern Gulf as a strong trough approaches.
Member Since: November 4, 2009 Posts: 0 Comments: 6577
669. weatherlover94
11:31 PM GMT on October 19, 2010
this is from 4 pm

1. OBSERVATIONS FROM AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT
INVESTIGATING THE AREA OF LOW PRESSURE...ABOUT MIDWAY BETWEEN
HONDURAS AND THE CAYMAN ISLANDS...INDICATE THAT A BROAD LOW-LEVEL
CIRCULATION HAS FORMED. CONDITIONS APPEAR CONDUCIVE FOR SOME
DEVELOPMENT...AND ANY INCREASE IN THE ORGANIZATION OF THE
ASSOCIATED SHOWERS AND THUNDERSTORMS COULD LEAD TO THE FORMATION OF
A TROPICAL DEPRESSION. INTERESTS IN THE NORTHWEST CARIBBEAN SEA
SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. THERE IS A HIGH
CHANCE...70 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES TOWARD THE NORTH AT 5 TO 10
MPH.
Member Since: September 8, 2010 Posts: 0 Comments: 2218
668. Stormchaser2007
11:29 PM GMT on October 19, 2010

Member Since: June 9, 2007 Posts: 4 Comments: 15946
667. weatherlover94
11:29 PM GMT on October 19, 2010
Quoting stormwatcherCI:
I don't think he can help being sarcastic.


some people just cant i guess
Member Since: September 8, 2010 Posts: 0 Comments: 2218
666. stormwatcherCI
11:27 PM GMT on October 19, 2010
Quoting weatherlover94:


i could tell by the way he said it....i say if your not going to be serious and have serious questions and answers dont join this discussion dont you agree?
I don't think he can help being sarcastic.
Member Since: October 9, 2008 Posts: 0 Comments: 8424
665. weatherlover94
11:26 PM GMT on October 19, 2010
Quoting stormwatcherCI:
No he is not serious. He is being his usual sarcastic self.


i could tell by the way he said it....i say if your not going to be serious and have serious questions and answers dont join this discussion dont you agree?
Member Since: September 8, 2010 Posts: 0 Comments: 2218
664. shikori
11:26 PM GMT on October 19, 2010
Quoting kmanhurricaneman:
yessssssss!


NOOOOOOOOO!!!!! :(
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663. kmanhurricaneman
11:25 PM GMT on October 19, 2010
yessssssss!
Member Since: August 14, 2008 Posts: 0 Comments: 1002
662. stormwatcherCI
11:24 PM GMT on October 19, 2010
Quoting weatherlover94:


i hope your being serious.....if you are dont do any thing yet just wait and see when the models begin to cluster on track and strength then we need to worry if they forecast a big storm headed to the gulf coast or Florida or ucitan
No he is not serious. He is being his usual sarcastic self.
Member Since: October 9, 2008 Posts: 0 Comments: 8424
661. pilotguy1
11:24 PM GMT on October 19, 2010
Quoting weatherlover94:


i hope your being serious.....if you are dont do any thing yet just wait and see when the models begin to cluster on track and strength then we need to worry if they forecast a big storm headed to the gulf coast or Florida or ucitan


That is exactly what I am saying. I want to see where this thing is going before I start telling the world where it's going. The models are all over the place so let's just keep our powder dry until we have some idea instead of just blatting out all kinds with no idea of what's really going to happen.
Member Since: November 18, 2007 Posts: 0 Comments: 1030
660. shikori
11:23 PM GMT on October 19, 2010
Quoting kmanhurricaneman:
This just came in on my email from cayman hazard management-
Special Bulletin

4.pm.



Weather charts indicate that the broad area of low pressure covering the northwest Caribbean is becoming better organized. In response, the National Hurricane Center in Miami Florida has increased the possibility of a tropical depression forming over the northwest Caribbean.



Satellite pictures show a large area of heavy thunderstorms moving into the Cayman area in association with this system. Weather models and rainfall predictions indicate that another 2 to 4 inches are likely during the next 24 hours. Flooding of low lying areas is expected during the next 24 hours and residents should take necessary precautions.



The CI National Weather Service will continue to monitor the progress and development of this system. All residents are urged to stay tuned to the local media for further updates.



Weather conditions for the Cayman area can be found in the local weather forecast.



The next bulletin will be issued 7 a.m. tomorrow.



Does this mean I have to go to skewl
Member Since: October 11, 2010 Posts: 0 Comments: 314
659. stormwatcherCI
11:23 PM GMT on October 19, 2010
Quoting CyclonicVoyage:


That was an educated statement based on the current movement.

GFDL
Please tell me if I am understanding this correctly. Going NE until it reaches just south of Eastern Cuba and then back West ?
Member Since: October 9, 2008 Posts: 0 Comments: 8424
658. utilaeastwind
11:22 PM GMT on October 19, 2010
The MJO seems to be getting sucked into the COC and snuffing out convection along the way.

It will be interesting once the MJO pattern changes.
Member Since: October 12, 2007 Posts: 0 Comments: 192
657. Bordonaro
11:22 PM GMT on October 19, 2010
Member Since: August 25, 2009 Posts: 20 Comments: 6785
656. kmanhurricaneman
11:21 PM GMT on October 19, 2010
This just came in on my email from cayman hazard management-
Special Bulletin

4.pm.



Weather charts indicate that the broad area of low pressure covering the northwest Caribbean is becoming better organized. In response, the National Hurricane Center in Miami Florida has increased the possibility of a tropical depression forming over the northwest Caribbean.



Satellite pictures show a large area of heavy thunderstorms moving into the Cayman area in association with this system. Weather models and rainfall predictions indicate that another 2 to 4 inches are likely during the next 24 hours. Flooding of low lying areas is expected during the next 24 hours and residents should take necessary precautions.



The CI National Weather Service will continue to monitor the progress and development of this system. All residents are urged to stay tuned to the local media for further updates.



Weather conditions for the Cayman area can be found in the local weather forecast.



The next bulletin will be issued 7 a.m. tomorrow.

Member Since: August 14, 2008 Posts: 0 Comments: 1002
655. weatherlover94
11:21 PM GMT on October 19, 2010
Quoting shikori:


agreed


me to
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654. shikori
11:20 PM GMT on October 19, 2010
Quoting CyclonicVoyage:


That was an educated statement based on the current movement.

GFDL


agreed
Member Since: October 11, 2010 Posts: 0 Comments: 314
653. weatherlover94
11:19 PM GMT on October 19, 2010
Quoting pilotguy1:


What are we to do?


i hope your being serious.....if you are dont do any thing yet just wait and see when the models begin to cluster on track and strength then we need to worry if they forecast a big storm headed to the gulf coast or Florida or ucitan
Member Since: September 8, 2010 Posts: 0 Comments: 2218
652. CyclonicVoyage
11:18 PM GMT on October 19, 2010
Quoting weatherlover94:


these models have this storm going all over the place


That was an educated statement based on the current movement.

GFDL
Member Since: January 30, 2010 Posts: 0 Comments: 3259
651. PSLFLCaneVet
11:18 PM GMT on October 19, 2010
Quoting CosmicEvents:
Maybe, butI think they'll more likely hold off till 11.


You're just raking it in.
Member Since: July 23, 2010 Posts: 1 Comments: 12414
Quoting weatherlover94:


these models have this storm going all over the place


What are we to do?
Member Since: November 18, 2007 Posts: 0 Comments: 1030
Quoting CyclonicVoyage:


GFDL?


these models have this storm going all over the place
Member Since: September 8, 2010 Posts: 0 Comments: 2218
looking at last good visible images 99L is starting to tighten up.
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The landfall of Megi

Member Since: June 9, 2007 Posts: 4 Comments: 15946
Quoting stormpetrol:

Personally I always try and be prepared throughout hurricane season, but I'm a bit scared of this as it appears to be drifting/moving slightly E of due north and could be on top of us strenghthening without hardly moving and people get caught offguard though to the NHC credit, the did caution the NW caribbean to monitor this system closely!


GFDL?
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Quoting stormpetrol:

Personally I always try and be prepared throughout hurricane season, but I'm a bit scared of this as it appears to be drifting/moving slightly E of due north and could be on top of us strenghthening without hardly moving and people get caught offguard though to the NHC credit, the did caution the NW caribbean to monitor this system closely!
We had time to prepare for Ivan but none for Paloma.
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TRUE DAT!!!
Member Since: August 14, 2008 Posts: 0 Comments: 1002

Member Since: June 9, 2007 Posts: 4 Comments: 15946
Quoting kmanhurricaneman:
NHC is doing what they do best ITS CALLED "CYA"

Personally I always try and be prepared throughout hurricane season, but I'm a bit scared of this as it appears to be drifting/moving slightly E of due north and could be on top of us strenghthening without hardly moving and people get caught offguard though to the NHC credit, the did caution the NW caribbean to monitor this system closely!
Member Since: Posts: Comments:
Best Track Position and Intensity as of:
Tuesday, October 19, 2010 18:00 Z

Location at the time:
187 statue miles (300 km) to the SW (225°) from George Town, Cayman Islands (GBR).

Wind (1 min. avg.):
30 knots (~35 mph | 15 m/s | 56 km/h)

Pressure:
1008 mb (29.77 inHg | 1008 hPa)

Coordinates:
17.4N 83.4W

Source:
National Hurricane Center's (NHC)
Automated Tropical Cyclone Forecasting System (ATCF)

99L
Member Since: September 8, 2010 Posts: 0 Comments: 2218
Quoting stormwatcherCI:
It is not too far off from certain Caribbean land masses and we have seen how fast they can develop and we have seen the destruction.


Oh gosh.
Member Since: November 18, 2007 Posts: 0 Comments: 1030
I think the HWRF and the GFDL have done fine so far
Member Since: October 11, 2010 Posts: 0 Comments: 314
Quoting pilotguy1:
Why you all so excited to see a upgrade? It is what it is until it threatens some land mass.
It is not too far off from certain Caribbean land masses and we have seen how fast they can develop and we have seen the destruction.
Member Since: October 9, 2008 Posts: 0 Comments: 8424
Quoting Autistic2:


I am he as you are he as you are me and we are all not JFV.

I am the eggman, they are the eggmen.
I am the walrus, go,go,go, JFV
Boy, you been a naughty little JFV. you let Taz down.
I am the eggman, they are the eggmen.
I am the walrus, goo goo g'joob.

Sitting in an dark room waiting for the NHC.

Expert textpert choking smokers,
Don't you thing JFV laughs at you?



LOL
Member Since: October 9, 2008 Posts: 0 Comments: 8424
Member Since: Posts: Comments:
Quoting Grothar:
You have to agree that the GFS models have the best indication as to where 99L will go!!!!! No doubt in my mind, what little there is left of it.



oh my goodness these models have no idea lol
Member Since: September 8, 2010 Posts: 0 Comments: 2218
Why you all so excited to see a upgrade? It is what it is until it threatens some land mass.
Member Since: November 18, 2007 Posts: 0 Comments: 1030
wont 99 get a little boost as the night gos on?
Member Since: Posts: Comments:
Quoting WeatherNerdPR:
Good Evening (at least here it is...). 99L looks like a TD now.


good eve...it sure does every body is saying this will not threaten the us but i think it has a chance to...any one else agree?
Member Since: September 8, 2010 Posts: 0 Comments: 2218
Quoting stormpetrol:
TD#19 at 8pm I suspect!
Maybe, but I think they'll more likely hold off till 11.
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630. DDR
Quoting Bordonaro:

VERY! Normally drought conditions are "king" during a La Nina event for Southern CA and the SE US.

Hi bordonaro
Strange indeed,perhaps a one time event for them.

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NHC is doing what they do best ITS CALLED "CYA"
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Quoting kmanhurricaneman:
mmmmmmmm, possible!


Actually from all the data provided by HHs this is a TD, basically the NHC was just waiting for a small increase in convection and I personally think it has met that criteria, just my personal take!
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HEHEHEH
Member Since: August 14, 2008 Posts: 0 Comments: 1002
Quoting stormpetrol:
TD#19 at 8pm I suspect!

8 or 11pm. Depends whether or not they issue a Special Advisory.
Member Since: July 7, 2010 Posts: 0 Comments: 5725
Quoting KerryInNOLA:
When I look over my shoulder,What do you think I see ?Some other cat looking over His shoulder at me And he's strange, sure he's strange.You've got to pick up every stitch,You've got to pick up every stitch,Beatniks are out to make it rich,Oh no, must be the season of the witch,Must be the season of the witch, yeah,Must be the season of the witch.You've got to pick up every stitch,The rabbits running in the ditch,Beatniks are out to make it rich,Oh no, must be the season of the witch,Must be the season of the witch,Must be the season of the witch
TROLL
Member Since: August 14, 2008 Posts: 0 Comments: 1002

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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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