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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Kman, yes indeed.

Looks like their target position from yesterday was spot on as a starting point. 17.5N/83.5W.
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Quoting CosmicEvents:
Everytime that red exclamation mark is hit then someone from admin looks at the post. It's meant for more serious offenses...not to be used because a member doesn't like a post, etc. If a member keeps making posts that annoy, the best idea given by WU is to utilize the ignore feature. I'd recommend reading what WU posts down below on "How to Ignore a Blogger".


1) The red exclamation is meant to be used for comments that don't comply with the rules and standards of the blog. 2) Rule #1 of this blog states in part "general trollish behavior will not be tolerated". 3) Repeatedly posting the same question or statement with the sole intentions of provoking a response, wasting other users' time and energy, or creating confusion is the very definition of "trollish behavior". 4) As such, clicking the red exclamation to call the admin's attention in this case is not merely allowable, but mandated.

The problem with merely putting the troll on ignore, especially in a case such as this, is that newer/unfamiliar visitors who come here for information and education likely aren't aware that a particular comment is intentionally false and misleading. So, yes, please put them on ignore...but only after clicking the red exclamation.

Thanks!
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Good morning all.

Tropical Tidbit for Tuesday, October 19th, with Video
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16:24:00Z 26.933N 88.200W 392.6 mb
(~ 11.59 inHg) 7,645 meters
(~ 25,082 feet)
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Quoting Seastep:
They are flying.

Anyone have any idea when can can expect to start receiving some initial date from recon?
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120. flsky
Article re Megi

Link
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Quoting reedzone:
Just 5 years ago today....



With all the talk this year about the fifth anniversary of Katrina, I almost forgot about that one!
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Quoting reedzone:


Morning REAL Jeff, I think the chances should be bumped to 60-70%. I don't think it's quite at depression status yet, it needs more convection to sustain itself. Maybe yesterdays GFDL run wasn't so far off, TS tomorrow? Possibly.


I agree, this system is better organized, but is very limited with convection. When the HH get some data on this we will have much better idea of the detail of the system, until then it still looks to be fighting off the dry air.
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Quoting TampaSpin:
Who will be hit # 100,000 on my site. That person will get a cookie.......let me know.....LOL


Thank you all for visting my Blog,
Tim...

VISTORS CURRENTLY ONLINE VIEWING.

2

View My Stats
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100000

Cookie please!

Hope that big blocking high does its job.
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Quoting Seastep:
They are flying.


Just saw that. Good news
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting Neapolitan:


Shear might be a limiting factor, but with the exception of a thin sliver at the top, temps are warm enough throughout the GOM and Caribbean. Yes, temps are cooler than they were a month ago, but there's a big difference here between "cooler" and "cold":

Click for larger image:

Appropriate tropical weather-related image



I think it is possible that a minimal hurricane could move fairly far north in the GOM, if the shear profile is favorable when it comes up.

But I doubt that the water temps in the Gulf are warm enough to support a major 'cane any longer. And it would probably be at least a week before anything related to the current 99L could make it this far north.

Looking back in history, there have not been many major hurricanes moving above latitude 25N after the middle of October. My guess is that those which did happened in years when cold fronts had not yet penetrated that far to the south.

When people see a developing cyclone in the Caribbean these days in mid to late October, they usually think of Wilma. My own personal opinion is that a better analog for the current situation may be Hurricane Mitch in 1998, which became a Cat 5 and wobbled around down near Honduras for days before moving north. Mitch bounced off the Yucatan and eventually made landfall in SW Florida as a moderate to strong tropical storm, if my memory is accurate.

We could actually use a weak TS this year, since it has been almost desert-like for about three weeks and without a drop of rain since sometime in late September.
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They are flying.
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Quoting Jeff9641:
I think Richard will be our 5th major cane of the season. What concerns me is the GFDL seems to have a better handle of the placement of 99L. also the NAM is latching on to the northern placement as well. It will be interesting to see what the GFS does on the 12Z run because this moisture will have to be accounted for later this weekend and into next week as a trough dips into the SE US. Today in the C FL it is the most humid it's been in awhile and it's starting to feel like summer again. Highs are forecast to be near 90 in orlando for days with rain increasing early next week as a frontal trough approaches.


That increase was predicted for now in the forecast as I recall and then expected to move out in a few days and return to the dryer cooler air again, I can't find my source at the moment it was also placed on the blog here about 4-5 days ago.
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111. 7544
so is recon going today ?
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Hmmmm...where's DJ? Where's Patrap? I can't decide on my own if we need a jaws theme post yet or not...
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Quoting Neapolitan:


Tampa: Oracle28 is a particularly annoying troll; he or she brings up the XTRP model a dozen or so times a day, apparently in the childish belief that wasting people's time and goodwill is somehow humorous. I suggest you just hit the red exclamation mark, and ignore.
Everytime that red exclamation mark is hit then someone from admin looks at the post. It's meant for more serious offenses...not to be used because a member doesn't like a post, etc. If a member keeps making posts that annoy, the best idea given by WU is to utilize the ignore feature. I'd recommend reading what WU posts down below on "How to Ignore a Blogger".
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Closed circulation at 17.5N 84W
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"Richie" is starting to get his swerve on. I think HH should at least take a look :)
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NHC meeting going on now on closed doors, they are speculating T.S. by today, they are compiling all the data from this blog and making a decision by 2pm advisory.
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Quoting FLWaterFront:


OK, sorry. As I said, I am fairly new here so I didn't know that "it" had been doing that for so long. I saw other comments though besides just the XTRP thing and which were a bit more humorous.

But if this has gone on and on and on it would get annoying. As I said, didn't know that part of the story.
Hi Fl, you have to have a thick skin to be on this blog, if you are going to put your opinions up. But it is a great blog with a lot of good imput. Sometimes it helps just to sit back and read for a while to learn the "characters". If you do not like a comment you can click on the - or if you are really offended you can click on the red ! to report to admin. I have put some of the trolls on ignore, which really helps cut out the ----. And hopefully no one will think I am one. I am not quite sure what really consitutes a troll other than making really weird or sometimes just plan horrible comments. Welcome aboard!
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Quoting reedzone:
Just 5 years ago today....



Impressive
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Agree, Rufus, that convection is waning overall, but overall structure continues to improve.
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convection is dissappearing
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Just 5 years ago today....

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Quoting FLWaterFront:


The question though is whether or not the SST's in the GOM, which keep dropping slowly and/or the upper level shear profile at the latitudes above about 22N will prevent anything that comes up this way from doing any real damage.


Shear might be a limiting factor, but with the exception of a thin sliver at the top, temps are warm enough throughout the GOM and Caribbean. Yes, temps are cooler than they were a month ago, but there's a big difference here between "cooler" and "cold":

Click for larger image:

Appropriate tropical weather-related image

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Surface observations around 99L indicate that a closed circulation has formed to the north of Honduras. A due west wind is being reported out of Puerto Lempira, a station just south of the the low pressure center and satellite derived winds support a cyclonic circulation. Water vapor imagery shows the system is located within a rather moist environment despite unfavorable MJO conditions. The TCHP in the Caribbean continues to be supportive of intensification.
Some things to watch for that are inhibiting the system is the dry air push from the west and the wind shear as a result of the upper level trough.
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93. 7544
hmm maybe no recon today they wait till tomorow ?
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Quoting PakaSurvivor:


Did someone let you know it hit the northern Philippines?
No, I just read the post and checked it out afterwards. Thanks.
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Quoting mcluvincane:
The troughs that have spared the us this years my spell doom next week when a strong trough comes down and picks soon to be Richard up towards Florida as depicted in Levi's video yesterday


The question though is whether or not the SST's in the GOM, which keep dropping slowly and/or the upper level shear profile at the latitudes above about 22N will prevent anything that comes up this way from doing any real damage.
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Quoting LightningCharmer:
That model run is all over the place. Give it a couples hours and it'll be heading strait for London, England...LOL


How often does it update?
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Quoting reedzone:
I see a broad low, but no LLC in there. Glad the Hurricane Hunters are going in to investigate it more. Maybe that will jump some of the models that don't develop it.


NHC is thinking cyclone by tomorrow AM.
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Gotta run....TD by 5pm possibly.....TD by 11pm likely! See ya all.....

I have Most Major model loops and 4 differnt interactive satellite loops on the WebSite if anyone needs. EVeryone have a good day!
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Quoting Minnemike:
Hey FLWaterFront,
Really meant nothing personal by my post either, towards you. More or less took the opportunity to attempt educating other bloggers here who may also be new. Humor is good to have here, downright important at times! Good to have you along for the ride, most are good folk with GREAT info here. -Mike


Not a problem. All your points are valid and well-taken.
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I see a broad low, but no LLC in there. Glad the Hurricane Hunters are going in to investigate it more. Maybe that will jump some of the models that don't develop it.
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84. 7544
looks like conv forming around the spin trying to wrap around could see a td here soon
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Quoting Jeff9641:


Hi Reed, I think this goes straight to Richard. In the close visible images those low clouds are hauling on the southside of 99L's circulation. I think the GFDL is on to something here and I would pay close attention if I lived anywhere in the NW Caribbean.


Maybe a closed Surface Low? Don't know for sure but, your being slightly agressive there Jeff IMO.
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.
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im willing to be the hh find a td when they go out,sooooo ......td looks probable sometime today imo......w/the stationary front dissipating,if it drifts far enough north h.into.te gom could be a threater to fl....
Member Since: October 5, 2007 Posts: 20 Comments: 4970
Quoting pioggiasuper:


Oh ok calming, i just ignored him :) I've been on here lurking a while and i just get tired of his opinion always being wrong. Over and out!


Well, some people's opinions are wrong. But don't be ticked at him because he's wrong.
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Hey FLWaterFront,
Really meant nothing personal by my post either, towards you. More or less took the opportunity to attempt educating other bloggers here who may also be new. Humor is good to have here, downright important at times! Good to have you along for the ride, most are good folk with GREAT info here. -Mike
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The troughs that have spared the us this years my spell doom next week when a strong trough comes down and picks soon to be Richard up towards Florida as depicted in Levi's video yesterday
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RAMSDIS just put 99L up on their 1km floater.

Need a few hours to make the loop worthwhile. Although, even in the two frames you can see the overall rotation of the entire area.

Link

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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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