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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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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73. 7544
recon will fly today we should know more by then
Member Since: May 6, 2007 Posts: 0 Comments: 6857
Quoting Minnemike:
even when it's a question asked by the same person over and over and over and over and over again, ad nauseam? i find this ridiculously stupid, and simply annoying at the very least when people quote this user which i have on ignore, either to give the answer, again, and again, and again, and again, ad nauseam, or to complain yet again at the ridiculousness of it (as i do now, again) and yet some actually quote this blogger to state their support of such humor. well, please stop quoting Oracle's xtrap bs. if this complaint seems excessive and unnecessary, believe me it pales in comparison to weeks worth of this person's one liner, and all the fish caught by the bait.
Some just have a one-track mind. When the blog is busy, yes I ignore it as well but sometimes the overwhelming repetitive ridiculousness is amusing during slow periods. Sorry if this caused you angst. :)
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Quoting pioggiasuper:


You really are a complete idiot. Let the NWS do their job. They are the experts. YOU ARE NOT!


Calm down, this is a place to share opinions as well. Unless you're copying off someone ;)
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Quoting Minnemike:
even when it's a question asked by the same person over and over and over and over and over again, ad nauseam? i find this ridiculously stupid, and simply annoying at the very least when people quote this user which i have on ignore, either to give the answer, again, and again, and again, and again, ad nauseam, or to complain yet again at the ridiculousness of it (as i do now, again) and yet some actually quote this blogger to state their support of such humor. well, please stop quoting Oracle's xtrap bs. if this complaint seems excessive and unnecessary, believe me it pales in comparison to weeks worth of this person's one liner, and all the fish caught by the bait.


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.
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67. 7544
the clip the orange model might be right with the track imo
Member Since: May 6, 2007 Posts: 0 Comments: 6857
Quoting stormpetrol:
I think MIss Piggy is in the air Check Google Earth, non tasked mission


That's a training mission that is not going into 99L.
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Quoting Jeff9641:
This is a TD right now if not Richard. Look at this visible sat of 99L it's about 120 miles off of Honduras and is really increasing in spin. WOW!

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


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.
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Quoting oracle28:


Does the XTRP point to New Orleans or not?

Regarding the "he or she" comment, I prefer to be called "it". :)


Well, that comment did it right there.
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62. 7544
Quoting Jeff9641:
This is a TD right now if not Richard. Look at this visible sat of 99L it's about 120 miles off of Honduras and is really increasing in spin. WOW!

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


agree its shaping up good now
Member Since: May 6, 2007 Posts: 0 Comments: 6857
Quoting Jeff9641:
This is a TD right now if not Richard. Look at this visible sat of 99L it's about 120 miles off of Honduras and is really increasing in spin. WOW!

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


Yes the location is correct, but i certainly don't see a TD yet. Maybe by 11pm
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I think MIss Piggy is in the air Check Google Earth, non tasked mission
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In addition, they added a 12Z and 00Z flight for tomorrow. Maybe they are cancelling today's flight and going in tomorrow morning. Still don't see anything on tropicalatlantic.

000
NOUS42 KNHC 191515
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1115 AM EDT TUE 19 OCTOBER 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 20/1100Z TO 21/1100Z OCTOBER 2010
TCPOD NUMBER.....10-140

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (WESTERN CARIBBEAN)
FLIGHT ONE - TEAL 70
A. 20/1200Z
B. AFXXX 0219A CYCLONE
C. 20/0830Z
D. 18.0N 83.0W
E. 20/1130Z TO 20/2130Z
F. SFC TO 15,000 FT

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

2. SUCCEEDING DAY OUTLOOK: CONTINUE 12-HRLY FIXES
IF SYSTEM DEVELOPS AND IS A THREAT.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
JWP
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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.


Thanks, didn't know that.
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Quoting Neapolitan:

Your relative newness is probably why you appreciate it. Wait until you've seen it a hundred or a thousand times, then let us know how deep that appreciation has grown... ;-)


It has gotten particulary annoying for me, it will mislead a lot who read it.
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Who will be hit # 100,000 on my site. That person will get a cookie.......let me know.....LOL
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Recon plan just updated on NHC site and I do not see the mission as cancelled.
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45. 7544
99l might get further north before the high builds in and the front could catch it first and turn in nore to the ne sorta like paula did if this gets to be a td i think the new model runs will trend this way . imo unless it stalls then that will give more time fro the high to build and it will miss the front . no one knows whre 99l will go yet .
Member Since: May 6, 2007 Posts: 0 Comments: 6857
Quoting oracle28:


The XTRP sends this straight into New Orleans, let's hope it's wrong.


Even though I am relatively new here, I have learned to appreciate this particular brand of comic relief.
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Quoting oracle28:


The XTRP sends this straight into New Orleans, let's hope it's wrong.
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


The XTRP is not a model but just a straight line direction the system has been moving.
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I have not seen them cancel the 1800Z mission, but at the same time, no recon data available, which they usually turn on at mission start time of 1500Z, which is 10 minutes ago.

Hope they fly, but all in the dark, unless someone has additional info.
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Quoting Waltanater:
Thanks for the compliment there. Someone last week (don't remember who) made the comment that Megi was going to threaten "their" country, but never actually stated which country it was. Since I am just now seeing that this was a massive typhoon, I was just curious as to where it hit. No offense intended to anyone, nor do I wish it upon anyone. Just trying to curiously ask the question, lightly, without being to direct. Sorry if it was offensive to anyone out there. :)
'Might want to edit your comment then. I took it in an offensive way. Joking about non-landfalling tropical systems is usually safe; that is if you want to joke about tropical systems.
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Also, the convection is increasing throughout the system.

While I agree that they like to see convection and a closed center, proximity to land should win out, imo.

With the lack of obs down there, HH would confirm or discount the formation of a true surface low.
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Quoting Waltanater:
Thanks for the compliment there. Someone last week (don't remember who) made the comment that Megi was going to threaten "their" country, but never actually stated which country it was. Since I am just now seeing that this was a massive typhoon, I was just curious as to where it hit. No offense intended to anyone, nor do I wish it upon anyone. Just trying to curiously ask the question, lightly, without being to direct. Sorry if it was offensive to anyone out there. :)


Did someone let you know it hit the northern Philippines?
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Quoting oracle28:


The XTRP sends this straight into New Orleans, let's hope it's wrong.
That model run is all over the place. Give it a couples hours and it'll be heading strait for London, England...LOL
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Quoting kmanislander:


The one aspect that needs to improve some is that there is very little in the way of deep convection near or over the center as seen in this image. The NHC may want to see that improve before making any major change in their call on this so far. Winds are fairly light now and pressures nearby not very low which indicates that the surface feature is relatively weak but improving steadily.

I think the rotation is better established from 2500 feet up than at the surface as seen in the loops.



Looking at RGB, there appears to be some banding started. For SLP, it has dropped significantly and consolidated. That's a large (yet consolidating) area of 1010. Was 1012 and much broader yesterday.

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Quoting TampaSpin:
Tropical and Severe/Winter Weather Update

I projected 16 Named storms, 10 Hurricanes, 4 Major Hurricanes on June 7th. Its gonna be close.




your forcast is a little off we had 5 Major Hurricanes not 4
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Quoting kmanislander:
99L showing good vorticity all the way up to the 500 mb level ( 18,000 feet ) and surface obs indicating that a surface low has also formed. Shear is low and water temps high. Conditions aloft show an upper level high almost right on top of the center.

I don't see any inhibitors to this developing and we could have a TD within the next 12 to 18 hours IMO. Hopefully the HH will investigate later today and confirm what we have out there.


Big blocking High to the NOrth will steer 99L and yes probably a TD SW in a couple of days. You should be ok unless something freaky happens.
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Tropical and Severe/Winter Weather Update

I projected 16 Named storms, 10 Hurricanes, 4 Major Hurricanes on June 7th. Its gonna be close.
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My thoughts and prayers with all those in the path of Megi. Very impressive storm
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29. JRRP


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Quoting Seastep:


I think they will definitely fly. Should, at least. It meets the threshold, imo.


The one aspect that needs to improve some is that there is very little in the way of deep convection near or over the center as seen in this image. The NHC may want to see that improve before making any major change in their call on this so far. Winds are fairly light now and pressures nearby not very low which indicates that the surface feature is relatively weak but improving steadily.

I think the rotation is better established from 2500 feet up than at the surface as seen in the loops.

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Quoting kmanislander:
99L showing good vorticity all the way up to the 500 mb level ( 18,000 feet ) and surface obs indicating that a surface low has also formed. Shear is low and water temps high. Conditions aloft show an upper level high almost right on top of the center.

I don't see any inhibitors to this developing and we could have a TD within the next 12 to 18 hours IMO. Hopefully the HH will investigate later today and confirm what we have out there.


I think they will definitely fly. Should, at least. It meets the threshold, imo.
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Quoting Buhdog:
you been looking for that west wind Kman?


I have and it's there.

At buoy 42057 this is what we have:

Wind Direction (WDIR): SE ( 130 deg true )

No doubt that there is a surface low but not enough data to say whether it is closed or not. The ASCAT pass for this morning will download around 1 pm today and if it catches enough of that area in the swath will give a better indication of the state of the low ( ie. open, closed or close to closed )
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you been looking for that west wind Kman?
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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.