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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Quoting Stormchaser2007:
Extremely hostile.




looks mabie like the atmosphere is trying to moisten up a little but cant tell yet
Member Since: September 8, 2010 Posts: 0 Comments: 2187
724. IKE
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Hi Wunderfolks,
Models are all over the place with 99L

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...SPECIAL FEATURE...
AS OF 2100 UTC...A 1008 MB LOW IS CENTERED BETWEEN HONDURAS AND THE CAYMAN ISLANDS NEAR 17N83W. PATCHES OF SCATTERED MODERATE CONVECTION ARE FROM 16N-20N BETWEEN 76W-84W. UPPER LEVEL ANTICYCLONIC OUTFLOW IS OVER THE SURFACE LOW. THERE IS A CHANCE FOR THIS SYSTEM TO BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT DRIFTS NORTHWARD.

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Why did nhc drop the wave from CATL, I think should be at least a invest,convection is starting to fire up.



has good spin too.

Link
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Meh:

Member Since: September 10, 2007 Posts: 0 Comments: 11102



Member Since: June 9, 2007 Posts: 4 Comments: 15872
Quoting Stormchaser2007:
Extremely hostile.


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Evening Everyone,

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Quoting Stormchaser2007:
Extremely hostile.




GOOD! Let's hope it stays that way!
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Quoting Tazmanian:




my mother in law

LOL XD
Member Since: July 7, 2010 Posts: 0 Comments: 5672

Member Since: June 9, 2007 Posts: 4 Comments: 15872
It's a long shot to go north (those clouds down there). The wishcasters should look at Megi and re-think what could happen if you wishcast to much. Wishcasting is not a good thing to do , don't try it at home.
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Quoting Tazmanian:




my mother in law
. Lol + 1000
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Extremely hostile.


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Quoting pilotguy1:

Not at this time.


i am not sure there are so may models that show weakening as the storm gets close to Florida and several that show other stuff the thing to do is to watch and monitor dont jump to conclusions yet
Member Since: September 8, 2010 Posts: 0 Comments: 2187
Quoting Jeff9641:


Oh you will and it could move fas past Cuba toward FL. You will see landfall Tuesday in SW FL.
Looks to me like it heads towards the Yucatan after it goes NE to just south of Eastern Cuba.
Member Since: October 9, 2008 Posts: 0 Comments: 8322
Quoting Jeff9641:


Oh you will and it could move fas past Cuba toward FL. You will see landfall Tuesday in SW FL.


wow you are going out on a limb here, the damn thing has yet to form, lets wait and see
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Quoting Jeff9641:


Oh you will and it could move fas past Cuba toward FL. You will see landfall Tuesday in SW FL.


May I ask what region of Florida are you from?
Member Since: June 9, 2007 Posts: 4 Comments: 15872
Quoting Jeff9641:


Oh you will and it could move fas past Cuba toward FL. You will see landfall Tuesday in SW FL.


Why is it always south FL why not west central FL??
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Jeff, I live in Lake Worth, just south of West Palm Beach. Should I be getting my shudders ready and stock up on supplies?
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Quoting Stormchaser2007:
18z GFDL




im not sure does this show weakening or continued strengthening at the end of the period?
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99L has continued to get better organized though it still lacks organized and deep convection. Just a minor increase in organization will likely result in the formation of a tropical depression. My best guess as to when this will occur is during the morning hours of Wednesday.
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Quoting WeatherNerdPR:

What's that, well east of Megi?




my mother in law
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Quoting IKE:


You can see what's going on with 99L on water vapor...Link



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696. IKE
Quoting pilotguy1:


Looks pretty sparse.


You can see what's going on with 99L on water vapor...Link
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Quoting Bordonaro:
Typhoon Megi


What's that, well east of Megi?
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693. IKE
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Quoting stormwatcherCI:
That is not what I see on GFDL.
Exactly.

Same story different storm.

Not surprised at all.
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18z GFDL


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If we do get Richard tomorrow, we'll be up to 17-9-5.. given the unlikelihood that 'Richard' will be our last storm.. I think we'll see 2 more after 'Richard'
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Quoting Jeff9641:


No, NW then NE rapidly in the eastern Gulf as a strong trough approaches.
That is not what I see on GFDL.
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Member Since: July 8, 2005 Posts: 259 Comments: 23880
Perhaps by tomorrow morning, I will be saying good mornin' to Richard. And perhaps he makes some wicked eggs and bacon.

Looks like he's going to soon enough; not like Megi, mind you - Megi is making an epic breakfast (in the future!).
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only marginally favorable upper level winds that is not to good for a tropical system
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" ...UPPER-LEVEL WINDS ARE MARGINALLY CONDUCIVE FOR
DEVELOPMENT...AND THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION...."
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NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT TUE OCT 19 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A NEARLY STATIONARY AREA OF LOW PRESSURE IS CENTERED ABOUT 175 MILES
SOUTHWEST OF GRAND CAYMAN. SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH THE LOW HAVE CHANGED LITTLE IN ORGANIZATION OVER THE PAST
SEVERAL HOURS. UPPER-LEVEL WINDS ARE MARGINALLY CONDUCIVE FOR
DEVELOPMENT...AND THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION AT
ANY TIME TONIGHT OR WEDNESDAY AS IT REMAINS NEARLY STATIONARY.
INTERESTS IN THE NORTHWEST CARIBBEAN SEA SHOULD CONTINUE TO 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.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
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What time does elementary school start?
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18z GFDL

AL, 99, 2010101918, 03, GFDI, 0, 174N, 834W, 30, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 12, 182N, 828W, 41, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 24, 190N, 821W, 42, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 36, 196N, 813W, 46, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 48, 200N, 804W, 58, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 60, 203N, 800W, 74, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 72, 205N, 800W, 83, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 84, 207N, 806W, 85, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 96, 212N, 815W, 89, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 108, 219N, 826W, 92, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 120, 229N, 835W, 84, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 99, 2010101918, 03, GFDI, 132, 241N, 843W, 65, 0, , 34, NEQ, 0, 0, 0, 0,

Member Since: June 9, 2007 Posts: 4 Comments: 15872
I think we'll have something official tomorrow morning, I hope I'll get to see it before I go to school
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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.