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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about three hours ago
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check out the vis floater,click on fronts,the trough is doing a figure 8 near the low!!!!,i've nevr seen any thing like it....
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216. JRRP
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Quoting FLstormwarning:
That's a cat 3 heading for SW FL on the GFDL. Now we need the Euro and GFS to get onboard.

Ah I get it. You are using GFDL and HWRF probably, two models that are built to help track storms AFTER they form.
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1. AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT INVESTIGATING THE
AREA OF LOW PRESSURE OVER THE NORTHWESTERN CARIBBEAN SEA...ABOUT
MIDWAY BETWEEN HONDURAS AND THE CAYMAN ISLANDS...HAS NOT YET
COMPLETED ITS MISSION. ALTHOUGH PRELIMINARY DATA FROM THE AIRCRAFT
AND SATELLITE IMAGERY INDICATE THE SYSTEM HAS NOT IMPROVED IN
ORGANIZATION...ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN
CONDUCIVE FOR SOME DEVELOPMENT OF THIS DISTURBANCE OVER THE NEXT
COUPLE OF DAYS. THERE IS A MEDIUM CHANCE...50 PERCENT...OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT
MOVES TOWARD THE NORTH AT 5 TO 10 MPH.
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Quoting FLstormwarning:
There seems to be model consensus building now for a FL landfall at 180 hours to 196 hours.

Haha I can only laugh at this. First off the models are in consensus? GFS and CMC as well as a few others do not even have 99L forming into anything but a rain maker. Second off how can the models be in consensus of landfall of a storm that doesnt even exist yet?
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210. Ookla
I'm guessing we're going to see the models all over the place for the next 5 days. Maybe we'll get something more definite sometime this weekend.
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B wins...
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Quoting Stormchaser2007:
Gonna have to go with 50%


THERE IS A MEDIUM CHANCE...50 PERCENT...OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT
MOVES TOWARD THE NORTH AT 5 TO 10 MPH.
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Quoting Stormchaser2007:
Gonna have to go with 50%


you win, 50%
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204. HadesGodWyvern (Mod)
Typhoon "JUAN" is continuously moving slowly in a northwestward direction.

At 10:00 PM PhST, Typhoon Juan (Megi) located at 16.9°N 117.8°E or 270 km west northwest of Dagupan City has 10 minute sustained winds of 95 knots with gustiness up to 110 knots. The cyclone is reported as quasi-statinary

Signal Warnings
==============

Signal Warning #2 (60-100 kph winds)

Luzon Region
--------------
1.Ilocos Sur
2.La Union
3.Pangasinan

Signal Warning #1 (30-60 km/h winds)

Luzon Region
----------
1.Ilocos Norte
2.Abra
3.Mt. Province
4.Benguet
5.Tarlac
6.Pampanga
7.Zambales
8.Bataan
9.Cavite
10.Metro Manila

Additional Information
========================
Public Storm Warning Signals elsewhere are now lowered.

Residents living in low lying and mountainous areas under Public Storm Warning Signals are alerted against possible flash floods and landslides.

Residents along the coastal areas of Western Luzon are alerted of possible storm surges.

The public and the disaster coordinating councils concerned are advised to take appropriate actions, monitor the hourly updates and watch for the next bulletin to be issued at 5 AM tomorrow.
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Quoting Jeff9641:
CMC is now latching onto this solution as well. although it is west of the HWRF and GFDL but the end result seems to be the same and that is FL landfall at 196 hours.

But Jeff...the season is supposed to be over.lol..IMO..which is just my opinion, this season will carry on through mid to 3rd week of November..just an opinion though.
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Quoting weatherman12345:
POLL TIME!!
What will the NHC have 99L at the 2:00 PM TWO
A. 40%
B. 50%
C. 60%
D. 70%
E. HIGHER %


My question would be, and excuse me because I haven't looked much at all today, has there been any increase in organization since 8am to warrant raising the odds?

In looking at the 8am discussion, the NHC thought this flight was necessary, so, I will go with C 60%.
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Quoting kmanislander:
Good afternoon. The HH should soon be starting the descent into 99L.

I doubt the NHC would go higher than 60% being this close to having real onsite data to work with. They can always raise it later today or go to TD status if warranted but I don't see them getting aggressive on the formation potential when the next two hours will tell them precisely where matters stand.

Just my view FWIW.


My thoughts exactly
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The sarcasm makes it funny that's all!
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Why do we even go by the XTRP at all when we all know it will be wrong 100% of the time later!? Is this the earliest level of extrapolating its projected path?
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Good afternoon. The HH should soon be starting the descent into 99L.

I doubt the NHC would go higher than 60% being this close to having real onsite data to work with. They can always raise it later today or go to TD status if warranted but I don't see them getting aggressive on the formation potential when the next two hours will tell them precisely where matters stand.

Just my view FWIW.
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XTRP -- I believe is the extrapolated movement based on current forward motion, (basically a straight line)

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It's not even in good format. Each word is on its own line! Not even in paragraph form. Very hard to read.
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Quoting Jeff9641:
You knida get the feeling that what Levi32 and myself have been saying about future Richard impacting FL are becoming real now as the HWRF is getting in line with the GFDL when it comes to track. Richard will have to move NE next week as a strong trough pushes SE from the midwest.

http://www.coaps.fsu.edu/~maue/extreme/hwrf/invest99l.2010101912_wind.png


These Mid-October storms always make my stomach turn. The longer it sits there, your right, it WILL eventually get drawn N & NE in your status quo October cyclone track.

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Gonna have to go with 50%
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Quoting Neapolitan:

This is my last statement on the subject, as I don't want to bore people any further than I probably already have: ;-)

I appreciate your detailed and in-depth analysis. And you're correct, for the most part. However, trollish behavior is not a "difference of opinion". Lemme 'splain:

If I come on this site once and say, "I believe a Cat 5 hurricane is headed toward Miami!", that's okay; it was my opinion, it was just the one time, I was corrected, and we've all moved on. If, however, I come on here every hour for days on end and post the same thing just to get a rise out of people and/or just to confuse them, I would no longer simply be giving my opinion; I would, rather, be engaging in well-known trollish behavior (in fact, it's how the term troll originated), which is expressly forbidden by the rules of the blog, and which I would expect to have reported to the admins. That is, then, what I'll continue to do with Oracle28's incessant and boorish "XTRP" comments, and hope everyone else does the same.

That is, after all, how successful online communites work, no? ;-)

I learned two things from this. One is your spend too much time on your computer and take a blog way way way to serious. Second, based on your picture you are trying to use the force to create this so called Cat 5 hurricane you are talking about haha.

On a side note 99L is at least 48 hours away from TD status. Nice little trough in south central US which will play a factor in the coming days.
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Quoting oracle28:


Lots of people repeatedly refer to the GFS GFDL models on a daily basis. You just don't like my posts. Using the XTRP model to analyze is no different, IMO


I find this hilarious! If soemone doesn't like the XTRP model comments just ignore Oracle28 don't make such a big deal out of it!
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Quoting FtMyersgal:


60%
I think so too.
Member Since: October 9, 2008 Posts: 0 Comments: 8371
Quoting Jeff9641:


Sorry! I will behave now!
promises, promises...lol

:)
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E
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There is also a non-tasked mission underway, looks like an upper air flight in the SEastern GOM.

Non-Tasked Missions in 2010

Date Mission Identifier Agency Aircraft Product(s) Map
10/19 Train NOAA N43RF URNT15
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Quoting weatherman12345:
POLL TIME!!
What will the NHC have 99L at the 2:00 PM TWO
A. 40%
B. 50%
C. 60%
D. 70%
E. HIGHER %


60%
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Legend Of The Seas assist in Rescue so far they have rescued 15 of the 22 crew members from a small downed ship in the Taiwan Straight.

This is from A Cruise Board. News coming from current passengers on ship. 20 foot seas in area of rescue
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176. Jeff9641 12:32 PM CDT on October 19, 2010

Thanks...
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Quoting Ineluki:


Go get 'em, Internet Tough Guy. You might want to look into not taking this stuff too seriously. Just a thought.


Who's worse, Internet Tough Guy or Internet Blog Monitor?

99L will not affect the U.S. gulf coast
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this invest is fighting more windshear than paula. the leftovers of her are trying in the bahamas.
Member Since: September 11, 2010 Posts: 1 Comments: 4587
Hmmm..just like before Paula..where are all those insisting the season was over..Saw a few post yesterday jumping on people for saying this would become a storm.
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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.